US007050725B2

(12) United States Patent (10) Patent No.: US 7,050,725 B2 Jingu (45) Date of Patent: May 23, 2006

(54) IMAGE FORMING APPARATUS 5,373.350 A * 12/1994 Taylor et al...... EMPLOYING TWO PRINTING METHODS 5,563,694. A * 10/1996 Katayama ...... 5,729,785 A * 3/1998 Sakaizawa et al. ... (75) Inventor: Hidehito Jingu, Tokyo (JP) 5,781,823 A * 7/1998 Isobe et al...... 399.2 6,725,770 B1 * 4/2004 Maeda ...... 101 129 (73) Assignee: Oki Data Corporation, Tokyo (JP) FOREIGN PATENT DOCUMENTS (*) Notice: Subject to any disclaimer, the term of this JP 09-169474 6, 1997 patent is extended or adjusted under 35 k . U.S.C. 154(b) by 0 days. cited by examiner Primaryy Examiner—Louis Arana (21) Appl. No.: 10/790,041 (74) Attorney, Agent, or Firm—Rabin & Berdo, PC

(65) Prior Publication Data US 2004/0175191 A1 Sep. 9, 2004 An image forming apparatus has a first image forming unit and a second image forming unit that form images by (30) Foreign Application Priority Data different methods on the same page. The image formed by Mar. 3, 2003 (JP) 2003-055.192 the second image forming unit is used as an identifying • - s 1- w - way - F · · · · · · · · · · · · · · · · · · · · · · · · · · · · · image to distinguish an original document made by the (51) Int. Cl. image forming apparatus from copies of the original docu GO3G I5/00 (2006.01) ment. The second image forming unit may, for example, (52) U.S. Cl 399/2: 39976 emboss or punch holes in the printing medium. The second (58) Field O f Classification search------399A2 image forming unit may accordingly be a serial impact dot ------39976 7 matrix printing unit or a stamping unit, while the first See application file for complete search history s printing unit may be, for example, an inkjet printing unit or an electrophotographic printing unit. One of the two image (56) References Cited forming units is preferably capable of making copies by printing on multiple-ply forms. U.S. PATENT DOCUMENTS 5,323,221 A 6, 1994 Tomimori et al...... 399.2 24 Claims, 37 Drawing Sheets

22

24b SIDM lu 24a PRINTING PRINTING UNIT UNIT U.S. Patent May 23, 2006 Sheet 1 of 37 US 7,050,725 B2

FIG. 1

22 21

24b SDM 24a PRINTING PRINTING UNIT UNIT U.S. Patent May 23, 2006 Sheet 2 of 37 US 7,050,725 B2

FIG.3

U.S. Patent May 23, 2006 Sheet 3 Of 37 US 7,050,725 B2

FIG.4

U.S. Patent May 23, 2006 Sheet 5 Of 37 US 7,050,725 B2

PRINTING PRINTING IMAGE FIG.6A UNIT POSITION INFORMATION (1) (2) (3)

FIG.7

NK-UET PRINTING

SERIAL IMPACT DOT MATRIX PRINTING

23

U.S. Patent May 23, 2006 Sheet 7 Of 37 US 7,050,725 B2

FIG.9A

U.S. Patent May 23, 2006 Sheet 9 Of 37 US 7,050,725 B2

FIG. 11

RECEIVE PRINT DATA S1

PRINTING UNIT SELECTION?

SEND DATA TOU SEND DATA TO SIDM S5 PRINTING UNIT PRINTING UNIT

UDATA PROCESSING SDM DATA PROCESSING S6

ALL, DATA RECEIVED?

WARM UP U AND SIDM S8 PRINTING UNITS U.S. Patent May 23, 2006 Sheet 10 Of 37 US 7,050,725 B2 FIG. 12 GD

DRIVE ROLLERS S9

FRONT EDGEAT 1ST SENSORT RESET UPRINTING POSITION

ANY UDATA TO PRINT ON CURRENT LINE2

PRINT DATA

S14

FRONT EDGEAT YES 2ND SENSORT RESET SDM PRINTING POSITION

ANY SIDMDATA TO PRINT ON CURRENT LINE

PRINT DATA

ALL, DATA PRINTED?

YES EUECT PRINTING MEDUM S19 U.S. Patent May 23, 2006 Sheet 11 of 37 US 7,050,725 B2 FIG. 13

22 72

27b. 27a EP 24a PRINTING 26 2b PRINTING 25 UNIT 23

3.

FIG. 14

74 U.S. Patent May 23, 2006 Sheet 12 Of 37 US 7,050,725 B2

27a 24b

27a OY 24b FIG. 15B / 3

27a 24b

FIG. 15C - O) O) 23

27a 24b O) OY O) 23 FIG. 15D (C) (C)

OY 23 FIG. 15E U.S. Patent May 23, 2006 Sheet 13 Of 37 US 7,050,725 B2

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FIG. 17A FIG. 17B

23a 23b U.S. Patent May 23, 2006 Sheet 15 of 37 US 7,050,725 B2

FIG. 18A FIG. 18B

61 23a 23b

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U.S. Patent May 23, 2006 Sheet 17 Of 37 US 7,050,725 B2

FIG20

RECEIVE PRINT DATA S21

PRINTING UNIT SELECTION?

SEND DATA TO EP SEND DATA TO SIDM S25 PRINTING UNIT PRINTING UNIT

EP DATA PROCESSING SDM DATA PROCESSING S26

ALL, DATA RECEIVED?

WARM UP EP AND SDM S28 PRINTING UNITS U.S. Patent May 23, 2006 Sheet 18 Of 37 US 7,050,725 B2 (2) FIG21

S30

FRONT EDGEAT YES 1ST SENSORT RESET EP PRINTING S31 POSITION

S32 ANY EP DATA YES TO PRINT ON CURRENT DOT LINE PRINT ONE DOT LINE S33

S34

YES TIME ta. ELAPSED2 DRIVE 2ND ROLLERS S35

S36

FRONT EDGE AT YES 2ND SENSORT RESET SDM PRINTING S37 POSITION

S38

ANY SDM DATA YES TO PRINT ON CURRENT LINE PRINT ONE LINE S39

S40

ALL, DATA PRINTED? NO

YES EUECT PRINTING MEDIUM S41 U.S. Patent May 23, 2006 Sheet 19 Of 37 US 7,050,725 B2 FIG.22

81

22 28a Zs28 72

SDM EP PRINTING PRINTING UNIT 26 UNIT

U.S. Patent May 23, 2006 Sheet 20 Of 37 US 7,050,725 B2

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FIG25A FIG.25B

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FIG.27 U.S. Patent May 23, 2006 Sheet 23 Of 37 US 7,050,725 B2

SHETTO}} }HOSNESLS|| ONILN|}}dd'E WSIN\/HOEWN }-}OSNESCINZ U.S. Patent May 23, 2006 Sheet 24 of 37 US 7,050,725 B2

FIG.29

RECEIVE PRINT DATA S51

PRINTING UNIT SELECTION?

SEND DATA TO EP SEND DATA TO SDM S56 PRINTING UNIT PRINTING UNIT

EP PRINTING PROCESS SDM PRINTING PROCESS S57

TURNOVER PROCESS U.S. Patent May 23, 2006 Sheet 25 Of 37 US 7,050,725 B2 FIG.30

START EP PRINTNG PROCESS

ANALYZE PRINTING POSITION S54-1 INFORMATION IN DATA1

TRANSPORT PRINTING MEDIUM S54-2 TO PRINTING POSITION

PRINT IMAGE S54-3

FIG.31

START TURNOVER PROCESS

TURN OVER PRINTING MEDUM S55-1 U.S. Patent May 23, 2006 Sheet 26 of 37 US 7,050,725 B2 FIG.32

START SDM PRINTING PROCESS

ANALYZE PRINTING POSITION S57-1 INFORMATION IN DATA2

TRANSPORT PRINTING MEDIUM us57-2 TO PRINTING POSITION

PRINT IMAGE S57-3

FIG.33

49 39 /

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FIG.34A FIG.34B

38 39 U.S. Patent May 23, 2006 Sheet 28 Of 37 US 7,050,725 B2 FIG.35A FIG.35B 23 91 23

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FIG.35C

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DMATE ISSUER XXXXYY A CORP U.S. Patent May 23, 2006 Sheet 29 Of 37 US 7,050,725 B2

FIG.36A FIG.36E

U.S. Patent May 23, 2006 Sheet 30 Of 37 US 7,050,725 B2 FIG.37A FIG.37B 23 101 23

DMATE XXXXYY

FIG.37C

103 23

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FIG.39

111 1-7 112 72

24b. PRINTING PRINTING UNIT UNIT U.S. Patent May 23, 2006 Sheet 32 Of 37 US 7,050,725 B2 FIG.40A

112 -

U.S. Patent May 23, 2006 Sheet 33 Of 37 US 7,050,725 B2

a spa spaces sessssss

U.S. Patent May 23, 2006 Sheet 34 of 37 US 7,050,725 B2

FIG.42A FIG.42B

23 121 23

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122 U.S. Patent May 23, 2006 Sheet 35. Of 37 US 7,050,725 B2

ONILN|}}dd'E SHETTO?) }}OSNES|S èHETTO?H_LNOO }-}OSNESONZ U.S. Patent May 23, 2006 Sheet 36 of 37 US 7,050,725 B2 FIG.44

S61

EP PRINTING UNIT S62 EP PRINTING PROCEss-S63 FixED PRINTing process-ss

FIG.45

START EP PRINTING PROCESS

ANALYZE PRINTING POSITION S63-1 INFORMATION IN DATA

TRANSPORT PRINTING MEDIUM us3-2 TO PRINTING POSITION

PRINT IMAGE S63-3

U.S. Patent May 23, 2006 Sheet 37 Of 37 US 7,050,725 B2

FIG.46

START FIXED PRINTING PROCESS

TRANSPORT PRINTING MEDIUM S64-1 TO PRINTING POSITION

PRINT FIXED IMAGE S64-2 US 7,050,725 B2 1. 2 IMAGE FORMING APPARATUS unintended hands. The same problems arise if a copying EMPLOYING TWO PRINTING METHODS machine is used, because copying machines are also elec trophotographic, making it difficult to tell a copy from the BACKGROUND OF THE INVENTION original document. Similar problems arise when a document 5 printed by an inkjet printer is copied. 1. Field of the Invention The present invention relates to image forming apparatus SUMMARY OF THE INVENTION Such as printing apparatus. 2. Description of the Related Art An object of the present invention is to provide an image Several different image forming methods or printing 10 forming apparatus that can form images by a plurality of methods are used by commercially available image forming printing methods and can print documents that, when cop apparatus. Ordinarily, the user selects and uses an apparatus ied, are distinguishable from the copies. employing a printing method that Suits the use to which the The invented image forming apparatus has a first image apparatus will be put, as noted in Japanese Unexamined forming unit and a second image forming unit. The first and Patent Application Publication No. 9-169474. 15 second image forming units form images by different meth Electrophotographic image forming apparatus Such as ods on a single page. The second image forming unit forms laser printers and light-emitting-diode (LED) printers, an identifying image; the first image forming unit forms an referred to below as electrophotographic printers, forms a image different from the identifying image. The identifying latent image by illuminating the Surface of a photosensitive image preferably identifies the page as an original document drum, develops the latent image by applying toner, and page, enabling the original document page to be distin transfers the toner image from the photosensitive drum to guished from copies thereof. For example, the second image paper or other printing media. Since electrophotographic forming unit may have an impact mechanism that deforms printers can print at high speed with high quality, they are or punches holes in the page, thus producing an identifying widely used in business work. image that cannot be faithfully copied by a copying Serial impact dot matrix printers have an impact mecha 25 machine. nism with needle pins that strike an inked ribbon, thereby Either the first or the second image forming unit is transferring ink from the ribbon to the printing media and preferably capable of forming images on the multiple sheets forming an image made up of dots. The advantage of a serial of multiple-ply media. impact dot matrix printer is that it can make copies, as the The first image forming unit may be, for example, an ink force of the impact is also transmitted to the lower layers of 30 jet printing unit or an electrophotographic printing unit. The multiple-ply printing media. Disadvantages of serial impact second image forming unit may be, for example, a serial dot matrix printers include slow speed, inferior printing impact dot matrix printing unit or a stamping or marking unit quality, and noisy operation. Serial impact dot matrix print that forms a fixed mark. ers are now used mainly for office work that requires the making of copies. 35 BRIEF DESCRIPTION OF THE DRAWINGS Inkjet printers have a printing head with nozzles from which drops of ink are ejected, each ejected drop forming a In the attached drawings: dot on the printing medium. Inkjet printers can be classified FIG. 1 illustrates communication between an image form as piezoelectric or thermal, depending on the method by ing apparatus and a host device in the described embodi which the drops are ejected. As both types are comparatively 40 ments of the invention; quiet and inexpensive, inkjet printers have become very FIG. 2 shows the general arrangement of the image popular for personal use. forming part of the image forming apparatus in a first Thermal printers have a thermal head with heating ele embodiment; ments that heat an inked ribbon, thereby transferring ink FIG. 3 is a perspective view of the inkjet printing unit in from the ribbon to the printing media. A ribbon of the film 45 the first embodiment; type is normally employed. An advantage of thermal printers FIG. 4 is a perspective view of the serial impact dot matrix is their very high resolution, resulting in sharp printed printing unit in the first embodiment; images. FIG. 5 is a block diagram schematically showing the A problem with conventional image forming apparatus is structure of the image forming apparatus in the first embodi that each apparatus employs only a single printing method. 50 ment; Accordingly, there is no single apparatus that combines, say, FIGS. 6A, 6B, and 6C show the structure of print data in a multiple-ply copy-making capability with the speed and the first embodiment; quality of electrophotographic printing. When copies of an FIG. 7 shows an example of a printout produced accord electrophotographically printed document are required, it is ing to the print data shown in FIGS. 6B and 6C: necessary either to print the document again or to use a 55 FIGS. 8A, 8B, and 8C show unprinted, printed, and separate copying machine. copied media; Printing the document again takes time, however, and FIGS. 9A and 9B show a difference between the original since it is impossible to distinguish between the original in FIG. 8B and the copy in FIG. 8C; document and the printed copy, various problems tend to FIG. 10 is a timing diagram illustrating the operation of arise, especially in an office in which the document and copy 60 different components of the image forming apparatus in the are handled by more than one person. Typical problems first embodiment; include treating both documents as copies, so that the FIGS. 11 and 12 constitute a flowchart illustrating the original document fails to be delivered to its intended operation of the image forming apparatus in the first destination; treating both documents as originals, so that the embodiment; same document is delivered twice to the same destination; 65 FIG. 13 shows the general arrangement of the image failing to make a necessary copy; making unnecessary forming part of the image forming apparatus in a second copies; and losing track of copies, which may then fall into embodiment; US 7,050,725 B2 3 4 FIG. 14 is a perspective view of the electrophotographic FIG. 40B is a top view of the fixed printing unit in the printing unit in the second embodiment; sixth embodiment; FIGS. 15A, 15B, 15C, 15D, and 15E illustrate various FIG. 40C shows a fixed mark printed by the fixed printing stages of media transport in the second embodiment; unit in the sixth embodiment; FIG. 16 is a block diagram schematically showing the FIG. 41 is a block diagram Schematically showing the structure of the image forming apparatus in the second structure of the image forming apparatus in the sixth embodiment; embodiment; FIGS. 17A and 17B show a pair of media sheets that, FIGS. 42A and 42B show media before and after printing when attached, constitute a two-ply pressure-sensitive form in the sixth embodiment; used in the second embodiment; 10 FIGS. 18A and 18B show the same pair of media sheets FIG. 43 is a timing diagram illustrating the operation of after printing in the second embodiment; the image forming apparatus in the sixth embodiment; FIG. 19 is a timing diagram illustrating the operation of FIG. 44 is a flowchart illustrating the operation of the different components of the image forming apparatus in the image forming apparatus in the sixth embodiment; second embodiment; 15 FIG. 45 is a flowchart illustrating the subroutine that FIGS. 20 and 21 constitute a flowchart illustrating the carries out step S63 in FIG. 44; and operation of the image forming apparatus in the second FIG. 46 is a flowchart illustrating the subroutine that embodiment; carries out step S64 in FIG. 44. FIG. 22 shows the general arrangement of the image forming part of the image forming apparatus in a third DETAILED DESCRIPTION OF THE embodiment; INVENTION FIG. 23 is a side view of the image forming apparatus in the third embodiment; Embodiments of the invention will now be described with FIG. 24 is a block diagram schematically showing the reference to the attached drawings, in which like elements structure of the image forming apparatus in the third 25 are indicated by like reference characters. embodiment; The word print, as used herein, includes not only FIGS. 25A and 25B show media before and after printing printing with ink or toner but also printing methods that in the third embodiment; deform the printing media by, for example, punching holes FIG. 26 is an enlarged view of the identifying information or forming an embossed pattern. in the third embodiment; 30 FIG. 27 is a side view of the printed media in the third Referring to FIG. 1, in a first embodiment of the inven embodiment; tion, print data are generated in a host apparatus 11 and sent FIG. 28 is a timing diagram illustrating the operation of to an image forming apparatus 12, which prints an image different components of the image forming apparatus in the according to the received data. The print data include two third embodiment; 35 types of data, shown as DATA1 and DATA2. The host FIG. 29 is a flowchart illustrating the operation of the apparatus 11 is a computing device Such as a personal image forming apparatus in the third embodiment; computer, server, or workstation including a processing unit FIG. 30 is a flowchart illustrating the subroutine that Such as a central processing unit (CPU) or microprocessor carries out step S54 in FIG. 29: unit (MPU), memory devices such as a magnetic disk FIG. 31 is a flowchart illustrating the subroutine that 40 memory and semiconductor memory, a display Such as a carries out step S55 in FIG. 29: cathode ray tube (CRT) or liquid crystal display, input means FIG. 32 is a flowchart illustrating the subroutine that Such as a keyboard, and a communication interface. Any carries out step S57 in FIG. 29: type of computing device may be used as the image forming FIG. 33 is a sectional view of the printing head of the apparatus 12. The image forming apparatus 12 may be serial impact dot matrix printing unit in a fourth embodi 45 connected to a plurality of host apparatuses 11, but it will be ment, assumed below that there is only one host apparatus 11. The FIG. 34A shows the tips of the needle pins used in the image forming apparatus 12 thus receives print data from a print heads of the serial impact dot matrix printing units in single source and prints according to the received data, but the first, second, and third embodiments; some of the print data may also be stored internally in the FIG. 34B shows the tips of the needle pins used in the 50 image forming apparatus 12. Communication between the print head of the serial impact dot matrix printing unit in the host apparatus 11 and the image forming apparatus 12 takes fourth embodiment; place through a printer cable or a wired or wireless com FIGS. 35A, 35B, and 35C show unprinted, printed, and munication network, Such as a local area network (LAN), copied media in the fourth embodiment; wide area network (WAN), intranet, or the Internet. Any type FIGS. 36A and 36B are enlarged views showing the 55 of communication network may be used, and a plurality of difference between the original in FIG. 35B and the copy in communication networks may be combined. FIG. 35C; Referring to FIG. 2, the image forming apparatus 12 FIGS. 37A, 37B, and 37C show unprinted, printed, and comprises an inkjet (IJ) printing mechanism 21, which is copied media in a fifth embodiment; provided as a first image forming unit, a serial impact dot FIGS. 38A and 38B are enlarged views showing the 60 matrix (SIDM) printing mechanism 22, which is provided as difference between the original in FIG. 37B and the copy in a second image forming unit, a pair of rollers 24a, 24b, and FIG. 37C; a pair of sensors 25, 26. FIG. 39 shows the general arrangement of the image The inkjet printing unit 21 has the same mechanism as an forming part of the image forming apparatus in a sixth inkjet printer, and the serial impact dot matrix printing unit embodiment; 65 22 has the same mechanism as a serial impact dot matrix FIG. 40A is a side view of the fixed printing unit in the printer. The sensors 25, 26 detect the position of paper or sixth embodiment; other printing media 23. The rollers 24a and 24b transport US 7,050,725 B2 5 6 the printing media 23 on the basis of the positions detected comprises the rollers 24a, 24b shown in FIG. 2, and a by the sensors 25, 26 in the direction shown by the arrow driving mechanism, not shown in the drawings, for driving from a to b. these rollers. When the printing medium 23 reaches an appropriate The host apparatus 11 creates print data DATA1 and position, the inkjet printing unit 21 prints an image on the DATA2 as specified by the operator, and sends the print data printing medium 23 according to the first print data to the image forming apparatus 12. The print data include (DATA1) received from the host apparatus 11. When the instructions for printing an image in a certain position on the printing medium 23 reaches a further appropriate position, printing medium by means of the inkjet printing unit 21 and the serial impact dot matrix printing unit 22 prints an image serial impact dot matrix printing unit 22. on the printing medium 23 according to the second print data 10 The print data sent from the host apparatus 11 in this (DATA2) received from the host apparatus 11. The images embodiment have three blocks as shown in FIG. 6A: a printed according to DATA1 and DATA2 are thus both printing unit selection block (1) for selecting either the ink printed on a single page. jet printing unit 21 or the serial impact dot matrix printing The structure of the inkjet printing unit 21 will now be unit 22, a printing position information block (2) indicating described with reference to FIG. 3. The inkjet printing unit 15 the X and Y coordinates of the printing position on the 21 comprises a carriage shaft 32 and a carriage 31, which has printing medium 23, and an image information block (3) ink tanks 31a containing different colors of ink and a indicating the image to be printed. printing head. The printing head is disposed at the bottom of In the example of DATA1 shown in FIG. 6B, the printing the carriage 31 and is not visible in the drawing. The carriage unit selection information is set to 1, indicating that the ink 31 is mounted on the carriage shaft 32 in such a manner that jet printing unit 21 is selected. The printing position infor the carriage 31 can travel in the longitudinal direction of the mation is set to (50, 50), and the image information desig carriage shaft 32, as indicated by the double-headed arrow nates the character A. between 'c' and d. Printing takes place as the carriage 31 In the example of DATA2 shown in FIG. 6C, the printing travels in both directions. unit selection information is set to 2, indicating that the The structure of the serial impact dot matrix printing unit 25 serial impact dot matrix printing unit 22 is selected. The 22 will be described with reference to FIG. 4. The serial printing position information is set to (100, 100), and the impact dot matrix printing unit 22 comprises a carriage 40 image information designates the character B. slidably mounted on a carriage shaft 41. A printing head 49 The page printed according to DATA1 in FIG. 6B and is mounted on the carriage 40. A motor (not shown) drives DATA2 in FIG. 6C is shown in FIG. 7. The letter A is the carriage 40 back and forth along the carriage shaft 41. 30 The printing head 49 prints on the printing medium (not printed by the inkjet printing unit 21; the letter B is printed shown) as the carriage 40 travels in both directions. The by the serial impact dot matrix printing unit 22. printing mechanism in the printing head 49 is an impact The data receiving unit 50 receives the print data sent mechanism that physically deforms the printing medium 23 from the host apparatus 11, distinguishes DATA1 from while printing, so that the printed image formed on the front 35 DATA2 by the printing unit selection information, sends side of the printing medium 23 is matched by an embossed DATA1 to the ink jet printing controller 51, and sends image formed on the reverse side of the printing medium 23. DATA2 to the serial impact dot matrix printing controller 55. The image forming apparatus 12 in the first embodiment If the print data sent from the host apparatus 11 do not will be further described with reference to FIG. 5. This include printing unit selection information, the print data are drawing shows that the inkjet printing unit 21 comprises an 40 sent to both control units. inkjet printing controller 51, inkjet printing mechanism 52. The inkjet printing mechanism 52 operates as specified and inkjet printing position memory 53, while the serial by the position information and image information sent to impact dot matrix printing unit 22 comprises a serial impact the ink jet printing controller 51 in DATA1. The serial dot matrix printing controller 55, serial impact dot matrix impact dot matrix printing mechanism 56 operates as speci printing mechanism 56, and serial impact dot matrix printing 45 fied by the position information and image information sent position memory 57. The image forming apparatus 12 also to the serial impact dot matrix printing controller 55 in comprises a data receiving unit 50 and a media transport DATA2. The media transport system 59 operates according system 59. to the position information in both DATA1 and DATA2. The data receiving unit 50 receives print data DATA1 and The inkjet printing position memory 53 is reset to 0 DATA2 from the host apparatus 11, sends the first print data 50 when the first sensor 25 detects the front edge of the printing DATA1 to the inkjet printing controller 51, and sends the medium 23. The serial impact dot matrix printing position second print data DATA2 to the serial impact dot matrix memory 57 is reset to 0 when the second sensor 26 detects printing controller 55. The ink jet printing controller 51 the front edge of the printing medium 23. After being reset, controls the operation of the inkjet printing mechanism 52 the values in the printing position memories 53, 57 are and ink jet printing position memory 53 according to 55 updated each time the rollers 24a, 24b advance the printing DATA1. The inkjet printing mechanism 52 prints on the medium 23 by a distance corresponding to a single printed printing medium. The inkjet printing position memory 53 line. For simplicity, it will be assumed that this distance, stores the current printing position of inkjet printing mecha referred to below as the linefeed distance, is the same for nism 52 on the printing medium. The serial impact dot both the inkjet printing unit 21 and the serial impact dot matrix printing controller 55 controls the operation of the 60 matrix printing unit 22. In both the inkjet and serial impact serial impact dot matrix printing mechanism 56 and serial dot matrix printing units 21, 22, a single printed line includes impact dot matrix printing position memory 57 according to a plurality of simultaneously printed raster lines or dot lines. DATA2. The serial impact dot matrix printing mechanism 56 During the printing process, the linefeed distance may vary prints on the printing medium. The serial impact dot matrix depending on whether lines of text or graphics are being printing position memory 57 stores the current printing 65 printed. The position memories 53, 57 are incremented position of the serial impact dot matrix printing mechanism according to the motion of the printing medium 23, regard 56 on the printing medium. The media transport system 59 less of whether any printing actually takes place. US 7,050,725 B2 7 8 An exemplary page printed by the first embodiment will In step S9 (FIG. 12), the media transport system 59 drives now be described. The printing media 23 used in this the rollers 24a, 24b to advance the printing medium 23, thus embodiment are cut sheets of plain white paper, as shown in performing a linefeed. The values in the inkjet printing FIG. 8A. Each sheet has two printed areas 61 and 62, as position memory 53 and serial impact dot matrix printing shown in FIG. 8B. Text is printed in the first area 61 by the position memory 57 are incremented accordingly. inkjet printing unit 21, and identifying information, such as In step S10, the inkjet printing unit 21 checks whether the the date of issuance, issuer, and a serial number is printed in first sensor 25 has just detected the front edge of the printing the second area 62 by the serial impact dot matrix printing medium 23. If so, that is, if the output of the first sensor 25 unit 22. has just changed from the state indicating that the printing If the printed medium 23 is copied on a copying machine, 10 medium 23 is not present to the state indicating that the which is not shown in the drawings, the copy has two printed printing medium 23 is present, the processing proceeds to areas 63 and 64, as shown in FIG. 8C. At a glance, the step S11. If not, the processing proceeds to step S12. original printed image on the medium 23 shown in FIG. 8B In step S11, the inkjet printing position memory 53 is and the copy made on the medium 23 shown in FIG. 8C reset to 'O'. seem to be the same. 15 In step S12, the inkjet printing unit 21 determines its Side views of the media, however, show a difference current line position on the printing medium 23 by Subtract between the original and the copy. The identifying informa ing a fixed quantity from the value indicated by the inkjet tion printed in area 62 on the original printing medium 23 by printing position memory 53, and checks whether DATA1 the serial impact dot matrix printing unit 22 is embossed, as includes any data to be printed on the current line. If so, the shown in FIG.9A. The copy of the identifying information processing proceeds to step S13. If not, the processing in area 64 of the copy is not embossed, as shown in FIG.9B. proceeds to step S14. The fixed quantity is spatially equiva Therefore, the printing medium 23 on which the original lent to the distance from the first sensor 25 to the ink jet image was printed can be distinguished from the printing printing head, and temporally equivalent to time t1 in FIG. medium 23' on which the copy is printed by checking 10. whether the identifying information is embossed as well as 25 In step S13, the inkjet printing unit 21 reads the necessary printed. number of rasters of stored data and prints the current line. The operation of the image forming apparatus 12 in the In step S14, the serial impact dot matrix printing unit 22 first embodiment will now be described with reference to checks whether the second sensor 26 has just detected the FIGS. 10 to 12. FIG. 10 is a timing diagram illustrating the front edge of the printing medium 23. If so, that is, when the operation of different components of the image forming 30 output of the second sensor 26 changes from the state apparatus 12. In each waveform in FIG. 10, the high level indicating that the printing medium 23 is not present to the indicates that the component is active and the low level state indicating that the printing medium 23 is present, the indicates the inactive state. For example, in the first wave processing proceeds to step S15. If not, the processing form the high level indicates that the rollers are turning proceeds to step S16. (intermittently). In the second waveform, the high level 35 In step S15, the serial impact dot matrix printing position indicates that the first sensor senses the presence of the memory 57 is reset to 0. printing medium. FIGS. 11 and 12 constitute a flowchart In step S16, the serial impact dot matrix printing unit 22 illustrating the printing of a page of the image forming determines its current line position on the printing medium apparatus 12. 23 by Subtracting a fixed quantity, equivalent to the distance In step S1 (FIG. 11), the data receiving unit 50 receives 40 from the second sensor 26 to the dot impact printing head or print data sent from the host apparatus 11. to time t2 in FIG. 10, from the value indicated by the serial In step S2, the data receiving unit 50 reads the printing impact dot matrix printing position memory 57, and checks unit selection information included in the print data. If the whether DATA2 includes any data to be printed on the printing unit selection information is set to 1, the data current line. If so, the processing proceeds to step S17. If receiving unit 50 identifies the print data as DATA1, 45 not, the processing proceeds to step S18. intended for the inkjet printing unit 21, and the processing In step S17, the serial impact dot matrix printing unit 22 proceeds to step S3. If the printing unit selection information reads the necessary number of rasters of stored data and is set to 2, the data receiving unit 50 identifies the print data prints the current line. as DATA2, intended for the serial impact dot matrix printing In step S18, the image forming apparatus 12 decides unit 22, and the processing proceeds to step S5. 50 whether the printing of all data has been completed, that is, In step S3, the data receiving unit 50 sends DATA1 to the whether the printing of both DATA1 by the inkjet printing inkjet printing unit 21. unit 21 and DATA2 by the serial impact dot matrix printing In step S4, the ink jet printing unit 21 receives and unit 22 has been finished. If so, the processing proceeds to processes DATA1 and stores the resulting image information step S19. If not, the processing returns to step S9. in raster data format. 55 In step S19, a media ejection distance is calculated by In step S5, the data receiving unit 50 sends DATA2 to the Subtracting the position indicated by the serial impact dot serial impact dot matrix printing unit 22. matrix printing position memory 57 from a known distance In step S6, the serial impact dot matrix printing unit 22 Substantially equal to the sum of the maximum media length receives and processes DATA2 and stores the resulting and the distance from the second sensor 26 to roller 24b. image information in raster data format. 60 This known distance is equivalent to time t3 in FIG. 10. In step S7, the data receiving unit 50 decides whether all Roller 24b is rotated for a time equivalent to the media print data for the page have been received from the host ejection distance to eject the printing medium 23; then the apparatus 11. If so, the processing proceeds to step S8. If not, processing ends. the processing returns to step S1, and the data receiving unit The processing loop from step S9 to step S18 includes 50 continues receiving the print data. 65 necessary delays for the printing operations in steps S13 and In step S8, the inkjet printing unit 21 and serial impact dot S17, during which the rotation of the rollers 24a, 24b is matrix printing unit 22 start warming up. stopped. Although the two printing steps S13 and S17 may US 7,050,725 B2 10 Sometimes take place simultaneously, the inkjet printing front edge of the printing medium 23 is advancing toward unit 21 can print faster than the serial impact dot matrix roller 27a as shown in FIG. 15A, roller 27a is held stopped. printing unit 22. The loop from step S9 to step S18 is When the front edge of the printing medium 23 reaches therefore repeated at a faster rate when only the ink jet roller 27a, roller 27a remains stopped while roller 24b printing unit 21 prints than when the serial impact dot matrix continues to rotate and transport the printing medium 23, printing unit 22 prints. When the printing steps S13 and S17 creating slack C. as shown in FIG. 15B. After a time are not performed, the rollers 24a, 24b are driven substan equivalent to at least one line printing cycle by the serial tially continuously. impact dot matrix printing unit 22, roller 27a starts rotating The identifying information printed in area 62 by the at a speed faster than roller 24b, and the slack C. is reduced serial impact dot matrix printing unit 22 differs from the text 10 as shown in FIGS. 15C and 15D. After feeding the printing printed in area 61 by the inkjet printing unit 21 in that the medium 23 through a distance equal to one line printed by identifying information is embossed. This difference cannot the serial impact dot matrix printing unit 22, roller 27a stops be copied by a copying machine. The printing medium 23 rotating and the slack C. increases again, as shown in FIG. bearing the original printed image can therefore be distin 15E. While the rollers 27a, 27b are being driven intermit guished from media bearing copies of the original printed 15 tently, rollers 24a, 24b are driven at the same average media image, so that copies can be identified as such and the transport speed. problems associated with unidentified copies can be As shown in FIG. 16, the image forming apparatus 71 avoided. In addition, because the serial impact dot matrix comprises a data receiving unit 50, the electrophotographic printing unit 22 prints on just a part of the printing medium printing unit 72, the serial impact dot matrix printing unit 22, 23, the attendant reduction in printing speed can be mini and a media transport system 59. The electrophotographic mized. printing unit 72 comprises an electrophotographic printing A second embodiment of the present invention will now controller 77, electrophotographic printing mechanism 78, be described. Referring to FIG. 13, the image forming and electrophotographic printing position memory 79; the apparatus 71 in the second embodiment comprises an elec serial impact dot matrix printing unit 22 comprises a serial trophotographic (EP) printing unit 72, which is provided as 25 impact dot matrix printing controller 55, serial impact dot a first image forming unit, a serial impact dot matrix printing matrix printing mechanism 56, and serial impact dot matrix unit 22, which is provided as a second image forming unit, printing position memory 57. a first pair of rollers 24a, 24b, a pair of sensors 25, 26, and The data receiving unit 50 receives print data comprising a second pair of rollers. 27a, 27b. The rollers transport DATA1 and DATA2 from the host apparatus 11, sends printing media 23 in the direction from a to b. 30 DATA1 to the electrophotographic printing controller 77 in Rollers 24a and 24b transport the printing medium 23 the electrophotographic printing unit 72, and sends DATA2 according to the position detected by the first sensor 25. to the serial impact dot matrix printing controller 55 in the When the printing medium 23 reaches an appropriate posi serial impact dot matrix printing unit 22. The electrophoto tion, the electrophotographic printing unit 72 prints an graphic printing controller 77 controls the operation of the image according to DATA1. Rollers 27a and 27b transport 35 electrophotographic printing mechanism 78 and electropho the printing medium 23 further according to the position tographic printing position memory 79 according to DATA1. detected by the second sensor 26. When the printing medium The electrophotographic printing mechanism 78 prints on 23 reaches an appropriate position, the serial impact dot the printing medium 23. The electrophotographic printing matrix printing unit 22 prints an image according to DATA2. position memory 79 stores the current printing position of Images based on DATA1 and DATA2 can both be printed on 40 the electrophotographic printing mechanism 78 on the print a single page. ing medium 23. As shown in FIG. 14, the electrophotographic printing The serial impact dot matrix printing unit 22 and media unit 72 comprises a main unit 73 and a process unit 74. The transport system 59 operate generally as in the first embodi main unit 73 includes a light-emitting-diode (LED) head 75: ment, except that the media transport system 59 controls two the process unit 74 includes a photosensitive drum 76 or 45 pairs of rollers 24a, 24b and 27a, 27b. other image forming member. As in the prior art, the Surface The host apparatus 11 creates print data DATA1 and of the photosensitive drum 76 is electrically charged, then DATA2 as specified by the operator and sends the print data illuminated by the LED head 75, forming an electrostatic to the image forming apparatus 12. The print data include latent image. Atoner image is formed by applying toner (not instructions for printing an image in a certain position on the shown) to the latent image, then is transferred and fused onto 50 printing medium 23 by means of the electrophotographic the printing medium 23. printing unit 72 or serial impact dot matrix printing unit 22. The serial impact dot matrix printing unit 22 provided as The print data have the same structure as in the first a second image forming unit has the same structure as in the embodiment. first embodiment. The data receiving unit 50 receives the print data sent In the second embodiment, rollers 24a and 24b rotate 55 from the host apparatus 11, distinguishes DATA1 from continuously; rollers 27a and 27b rotate in short angular DATA2 by the printing unit selection information, sends steps, that is, rollers 27a and 27b go through repeated DATA1 to the electrophotographic printing controller 77. start-and-stop cycles. While the first pair of rollers 24a, 24b and sends DATA2 to the serial impact dot matrix printing are rotating continuously, the electrophotographic printing controller 55. If the print data sent from the host apparatus unit 72 prints continuously. While the second pair of rollers 60 11 do not include printing unit selection information, the 27a, 27b are stopped, the serial impact dot matrix printing print data are sent to both control units. The printing unit 22 prints a single line. In order to Smooth out temporary algorithm in the second embodiment is the same as in the transport speed discrepancies, slack is provided in the print first embodiment. ing medium 23 between the electrophotographic printing The electrophotographic printing mechanism 78 operates unit 72 and the serial impact dot matrix printing unit 22. 65 as specified by the position information and image informa FIGS. 15A to 15E show an example of how the slack in tion sent to the electrophotographic printing controller 77 in the media changes in the second embodiment. While the DATA1. The serial impact dot matrix printing mechanism 56 US 7,050,725 B2 11 12 operates as specified by the position information and image In step S29 (FIG. 21), the media transport system 59 is information sent to the serial impact dot matrix printing activated. Rollers 24a and 24b begin rotating and continue controller 55 in DATA2. The media transport system 59 to rotate until the trailing edge of the printing medium 23 operates according to the position information in both passes the second sensor 26. Each time rollers 24a and 24b DATA1 and DATA2. advance the printing medium 23 by a distance corresponding An exemplary page printed by the second embodiment to a single dot line printed by the electrophotographic will now be described. The printing media 23 used in this printing unit 72, the value in the electrophotographic print embodiment are two-ply blank pressure-sensitive forms ing position memory 79 is incremented by one. comprising two sheets of paper detachably joined together at In step S30, the electrophotographic printing unit 72 the front edge. For clarity, the two sheets are shown detached 10 checks whether the first sensor 25 has just detected the front in FIGS. 17A and 17B. When pressure is applied to the edge of the printing medium 23. If so, that is, if the output two-ply form, the same image is printed on the top sheet 23a of the first sensor 25 has just changed from the state and the bottom sheet 23b. indicating that the printing medium 23 is not present to the After a form is printed by the image forming apparatus 71, state indicating that the printing medium 23 is present, the the top sheet 23a has two printed areas 61 and 62, as shown 15 processing proceeds to step S31. If not, the processing in FIG. 18A. The text in area 61 is printed by the electro proceeds to step S32. photographic printing unit 72, and identifying information In step S31, the electrophotographic printing position Such as the of date of issuance, issuer, and a serial number memory 79 is reset to 0. are printed by the serial impact dot matrix printing unit 22. In step S32, the electrophotographic printing unit 72 The bottom sheet 23b has only one printed area 65 with the determines its current dot line position on the printing same identifying information as in area 62, as shown in FIG. medium 23 by subtracting a fixed number of dot lines from 18B. Since the text in area 61 is not printed on the bottom the value indicated by the electrophotographic printing sheet 23b, the bottom sheet 23b can be used for document position memory 79, and checks whether DATA1 includes management with a high level of security. any data to be printed on the current dot line. A dot line is The serial impact dot matrix printing mechanism 56 25 equivalent to a single raster line of print data. The fixed provided as a second image forming unit in this embodiment number of dot lines corresponds substantially to the distance has an impact mechanism capable of forming images on from the first sensor 25 to the photosensitive drum 76 in the multiple-ply pressure-sensitive media. electrophotographic printing unit 72, and is equivalent to The operation of the image forming apparatus 71 in the time t1 in FIG. 19. If DATA1 includes data to be printed on second embodiment will now be described with reference to 30 the current dot line, the processing proceeds to step S33. If the following drawings. FIG. 19 is a timing diagram illus not, the processing proceeds to step S34. trating the operation of different components of the image In step S33, the electrophotographic printing unit 72 forming apparatus 71, the high waveform level indicating prints one dot line of stored data on the first sheet of the the active state and the low level the inactive state of the multiple-ply form. corresponding component. FIGS. 20 and 21 constitute a 35 In step S34, the serial impact dot matrix printing unit 22 flowchart illustrating the operation of the image forming decides whether the printing medium 23 has been advanced apparatus 71. far enough to reach roller 27a and produce the slack C. In step S21 (FIG. 20), the data receiving unit 50 receives shown in FIG. 15B. This decision is made by determining the print data sent from the host apparatus 11. the distance traveled by the printing medium 23 after In step S22, the data receiving unit 50 reads the printing 40 detection of its front edge by the first sensor 25. The unit selection information included in the print data. If the necessary distance is equal to the distance from the first printing unit selection information is set to 1, the data sensor 25 to roller 27a plus at least the linefeed distance of receiving unit 50 identifies the print data as DATA1, the serial impact dot matrix printing unit 22, and is equiva intended for the electrophotographic printing unit 72, and lent to time ta in FIG. 19. The decision is thus equivalent to the processing proceeds to step S23. If the printing unit 45 determining whether time ta has elapsed, as indicated in selection information is set to 2, the data receiving unit 50 FIG 21. identifies the print data as DATA2, intended for the serial When the printing medium 23 has advanced the necessary impact dot matrix printing unit 22, and the processing distance, and at fixed intervals thereafter, the processing proceeds to step S25. proceeds to step S35. At other times, the processing pro 50 ceeds to step S36. The fixed intervals are equal to the line In step S23, the data receiving unit 50 sends DATA1 to the printing cycle time of the serial impact dot matrix printing electrophotographic printing unit 72. unit 22, that is, to the time required for the serial impact dot In step S24, the electrophotographic printing unit 72 matrix printing mechanism 56 to print one line and the receives and processes DATA1 and stores the resulting second pair of rollers. 27a, 27b to feed the printing medium image information in raster data format. 55 23 to the next line position. As in the first embodiment, a line In step S25, the data receiving unit 50 sends DATA2 to the printed by the serial impact dot matrix printing unit 22 serial impact dot matrix printing unit 22. comprises a plurality of dot lines. In step S26, the serial impact dot matrix printing unit 22 In step S35, rollers 27a and 27b rotate through an angle receives and processes DATA2 and stores the resulting corresponding to the linefeed distance of the serial impact image information in raster data format. 60 dot matrix printing unit 22, and the serial impact dot matrix In step S27, the data receiving unit 50 decides whether all printing position memory 57 is incremented correspond print data have been received from the host apparatus 11. If ingly. After completing the linefeed, rollers 27a and 27b stop So, the processing proceeds to step S28. If not, the process temporarily. ing returns to step S21, and the data receiving unit 50 In step S36, the serial impact dot matrix printing unit 22 continues receiving the print data. 65 checks whether the second sensor 26 has just detected the In step S28, the electrophotographic printing unit 72 and front edge of the printing medium 23. If so, that is, if the serial impact dot matrix printing unit 22 start warming up. output of the second sensor 26 has just changed from the US 7,050,725 B2 13 14 state indicating that the printing medium 23 is not present to A third embodiment of the present invention will now be the state indicating that the printing medium 23 is present, described, omitting detailed descriptions of aspects of the the processing proceeds to step S37. If not, the processing structure, operation, and effects that are the same as in the proceeds to step S38. first or second embodiment. Referring to FIG. 22, the image forming apparatus 81 of In step S37, the serial impact dot matrix printing position the third embodiment comprises an electrophotographic memory 57 is reset to 0. printing unit 72, which is provided as a first image forming In step S38, the serial impact dot matrix printing unit 22 unit, a serial impact dot matrix printing unit 22, which is determines its current line position on the printing medium provided as a second image forming unit, a pair of rollers 23 by Subtracting a fixed quantity, equivalent the distance 10 24a, 24b, a pair of sensors 25, 26, and a media turnover unit from the second sensor 26 to the dot impact printing head or 28. The rollers 24a, 24b transport the printing medium 23 in to time t2 in FIG. 19, from the value indicated by the serial the direction from a to b. impact dot matrix printing position memory 57, and checks The electrophotographic printing unit 72 has the same whether DATA2 includes any data to be printed on the structure as in the second embodiment, and the serial impact current line. If so, the processing proceeds to step S39. If 15 dot matrix printing unit 22 has the same structure as in the not, the processing proceeds to step S40. second embodiment, except that it does not use an inked In step S39, the serial impact dot matrix printing unit 22 ribbon. Roller 24a transports the printing medium 23 according to reads the necessary number of rasters of stored data and the position detected by the first sensor 25. When the prints the current line on the first sheet of the multiple-ply printing medium 23 reaches an appropriate position, the form. Identifying information printed in area 62 is copied electrophotographic printing unit 72 prints an image accord onto the second sheet of the multiple-ply form. During this ing to DATA1 received from the host apparatus 11. A step, rollers. 27a and 27b remain stationary, while rollers 24a reversing roller 28a and a triangular switchback roller 28b in and 24b continue to rotate and the electrophotographic the media turnover unit 28 then turn the printing medium 23 printing unit 72 continues to print, if it has data to be printed. 25 over for printing on the reverse side. Roller 24b transports In step S40, the image forming apparatus 71 decides the printing medium 23 further according to the position whether the printing of all print data has been completed, detected by the second sensor 26. When the printing medium that is, whether printing based on both DATA1 for the 23 reaches an appropriate position, the serial impact dot electrophotographic printing unit 72 and DATA2 for the matrix printing unit 22 prints an embossed image according serial impact dot matrix printing unit 22 has been finished. 30 to DATA2. The embossed image is visible on both sides of If so, the processing proceeds to step S41. If not, the the printing medium 23, although it does not differ in color processing returns to step S30. from the background of the page. In step S41, a media ejection distance is calculated by The media turnover unit 28 will now be described with Subtracting the position indicated by the serial impact dot reference to FIG. 23. After the electrophotographic printing matrix printing position memory 57 from a known distance 35 unit 72 prints on one side of the printing medium 23, the Substantially equal to the sum of the maximum media length printing medium 23 is transported upward by the switchback and the distance from the second sensor 26 to roller 27b. roller 28b and reversing roller 28a, and stops while still held This known distance is equivalent to time t3 in FIG. 19. by the reversing roller 28a. The switchback roller 28b then Roller 27b is rotated for a time equivalent to the media changes orientation, and the reversing roller 28a rotates in ejection distance to eject the printing medium 23; then the 40 the reverse direction, sending the printing medium 23 to the processing ends. serial impact dot matrix printing unit 22. The image forming apparatus 81 in the third embodiment Although not indicated in the drawings, the rotational will now be further described with reference to FIG. 24. This speed of rollers 24a and 24b is preferably varied during the drawing shows that the electrophotographic printing unit 72 printing of the page. Before the serial impact dot matrix 45 comprises an electrophotographic printing controller 77 and printing unit 22 begins printing, the rollers 24a and 24b are electrophotographic printing mechanism 78, the serial preferably driven at the normal printing speed of the elec impact dot matrix printing unit 22 comprises a serial impact trophotographic printing unit 72. While the serial impact dot dot matrix printing controller 55 and serial impact dot matrix matrix printing unit 22 is printing, rollers 24a and 24b are printing mechanism 56, and the media transport system 59 slowed to match the printing speed of the serial impact dot 50 comprises the media turnover unit 28. The image forming matrix printing unit 22; that is, to match the average rota apparatus 81 further comprises a data receiving unit 50. tional speed of rollers 27a and 27b. When the serial impact The host apparatus 11 creates print data DATA1 and dot matrix printing unit 22 prints on just part of a page, as DATA2 as specified by the operator, and sends the print data in FIG. 18A, this arrangement minimizes the attendant to the image forming apparatus 81. The print data include reduction in printing speed. 55 instructions for printing an image in a certain position on the Regardless of printing speed, the electrophotographic printing medium 23 by means of the electrophotographic printing unit 72 prints at a higher resolution than the serial printing unit 72 or serial impact dot matrix printing unit 22. impact dot matrix printing unit 22, so a high-quality text The print data have the same structure as in the first image can be combined with the printing and copying of embodiment. document management information. 60 The data receiving unit 50 receives the print data sent The printing media 23 used in this embodiment are from the host apparatus 11, distinguishes DATA1 from two-ply forms attached at one edge, and they are transported DATA2 by the printing unit selection information, sends together as if they were a single sheet of paper, but the DATA1 to the electrophotographic printing controller 77. invention is not limited to this very simple type of multiple and sends DATA2 to the serial impact dot matrix printing ply media and media transport. Any type of multiple-ply 65 controller 55. If the print data sent from the host apparatus media may be used. The different sheets may be fed and 11 do not include printing unit selection information, the ejected through different paths. print data are sent to the electrophotographic printing con US 7,050,725 B2 15 16 troller 77. The printing algorithm in the third embodiment is The process in FIG. 29 is repeated until all data for the the same as in the first embodiment. current page have been received and printed. When the The electrophotographic printing mechanism 78 and image forming apparatus 81 receives both DATA1 and media transport system 59 operate as specified by the DATA2, steps S53 to S55 are carried out in the first position information and image information sent to the repetition and steps S56 and S57 in the second repetition. In electrophotographic printing controller 77 in DATA1. The this case, ejection of the printing medium 23 is completed serial impact dot matrix printing mechanism 56 and media after the elapse of time t5 in FIG. 28 from the completion of transport system 59 operate as specified by the position the printing by the serial impact dot matrix printing unit 22. information and image information sent to the serial impact The flowchart in FIG. 30 illustrates the subroutine that dot matrix printing controller 55 in DATA2. If double-sided 10 carries out step S54. printing is carried out, after the electrophotographic printing In step S54-1, the electrophotographic printing unit 72 unit 72 has printed on one side of the printing medium 23, analyzes the printing position information in DATA1. the printing medium 23 is turned over by the media turnover In step S54-2, the media transport system 59 transports unit 28 so that the impact mechanism of the serial impact dot the printing medium 23 to the printing position. matrix printing mechanism 56 strikes the reverse side of the 15 In step S54-3, the electrophotographic printing mecha printing medium 23. nism 78 prints the image described by DATA1; then the An exemplary page printed by the third embodiment will processing ends. now be described. The printing media 23 used in this The flowchart in FIG. 31 illustrates the subroutine that embodiment are cut sheets of plain white paper, as shown in carries out step S55. FIG. 25A. Each sheet has two printed areas 88 and 89, as In step S55-1, the printing medium 23 is transported to the shown in FIG. 25B. The document text, issuer, date of media turnover unit 28 and turned over, then the processing issuance, serial number, and so on are printed in the first area ends. 88 by the electrophotographic printing unit 72, and identi The flowchart in FIG. 32 illustrates the subroutine that fying information is printed in the second area 89 by the carries out step S57. serial impact dot matrix printing unit 22. FIG. 26 is an 25 In step S57-1, the serial impact dot matrix printing enlarged view of the identifying information. The image controller 55 analyzes the printing position information in printed in the second area 89 by the serial impact dot matrix DATA2. printing unit 22 is not printed withink but is only embossed, In step S57-2, the media transport system 59 transports as shown in FIG. 27, by striking from the reverse side. the printing medium 23 to the printing position. The operation of the image forming apparatus 81 in the 30 In step S57-3, the serial impact dot matrix printing third embodiment will now be described with reference to mechanism 56 prints the image described by DATA2; then FIGS. 28 to 32. FIG. 28 is a timing diagram illustrating the the processing ends. operation of different components of the image forming Since the identifying information printed by the serial apparatus in the third embodiment. FIG. 29 is a flowchart impact dot matrix printing unit 22 in this embodiment is only illustrating the operation of the image forming apparatus in 35 embossed, it is only faintly visible but is readily distinguish the third embodiment. FIGS. 30, 31, and 32 are flowcharts able by touch. If a copy is made by a copying machine, the illustrating subroutines included in the operation illustrated original can be distinguished from the copy by touching the in FIG. 29. identifying information. In step S51 (FIG. 29), the data receiving unit 50 receives A fourth embodiment of the present invention will now be the print data sent from the host apparatus 11. 40 described, omitting detailed descriptions of aspects of the In step S52, the data receiving unit 50 reads the printing structure, operation, and effects that are the same as in any unit selection information included in the print data. If the of the first to third embodiments. printing unit selection information is set to 1, the data The image forming units of the image forming apparatus receiving unit 50 identifies the print data as DATA1, in the fourth embodiment have the same general arrange intended for the electrophotographic printing unit 72, and 45 ment as in the second embodiment, shown in FIG. 13. The the processing proceeds to step S53. If the printing unit electrophotographic printing unit 72 provided as a first selection information is set to 2, the data receiving unit 50 image forming unit has the same structure as in the second identifies the print data as DATA2, intended for the serial embodiment. The serial impact dot matrix printing unit 22 impact dot matrix printing unit 22, and the processing provided as a second image forming unit has substantially 50 the same structure as in the first embodiment, but does not proceeds to step S56. have an inked ribbon. The operation of rollers 24a, 24b. 27a, In step S53, the data receiving unit 50 sends DATA1 to the 27b and the overall operation and structure of the image electrophotographic printing unit 72. forming apparatus 71 are the same as in the second embodi In step S54, the electrophotographic printing unit 72 ment. receives and processes DATA1 and prints the resulting 55 The structure of the printing head 49 of the serial impact image information. dot matrix printing unit 22 will now be described. The In step S55, the printing medium 23 is transported into the printing head 49 has needle pins 39, as shown in FIG. 33. media turnover unit 28 and turned over if necessary. If the that move longitudinally to strike the printing medium 23. printing medium 23 does not have to be turned over, it may While the needle pins 39 of the printing head 49 of the serial be ejected from the turnover unit 28 as indicated by the 60 impact dot matrix printing unit 22 in the first to third uppermost arrow in FIG. 23, or fed to the serial impact dot embodiments have flat tips as shown in FIG.34A, the needle matrix printing unit 22. pins 39 in the fourth embodiment have sharply pointed tips In step S56, the data receiving unit 50 sends DATA2 to the as shown in FIG. 34.B. The needle pins 39 of the serial serial impact dot matrix printing unit 22. impact dot matrix printing unit 22 in the fourth embodiment In step S57, the serial impact dot matrix printing unit 22 65 punch holes in the printing medium 23. receives and processes DATA2 and prints the resulting An exemplary page printed by the fourth embodiment will image information. now be described. The printing media 23 used in this US 7,050,725 B2 17 18 embodiment are cut sheets of plain white paper, as shown in shown in FIG.38A. The copy of the identifying image in the FIG. 35A. Each sheet has two printed areas 91 and 92, as second area 104 on the copy is not embossed or printed with shown in FIG. 35B. The document text, date of issuance, ink, but is printed only as a toner image, as shown in FIG. issuer, a serial number, and so on are printed by the 38B. electrophotographic printing unit 72 in the first area 91. The The printing medium 23 on which the original image was identifying information in the second area 92 is printed by printed can be distinguished from printing media 23' on the serial impact dot matrix printing unit 22. which copies are printed because the identifying image on If the printed printing medium 23 is copied by a copying the original is printed by both the electrophotographic machine, the copy has two printed areas 93 and 94, as shown printing unit 72 and serial impact dot matrix printing unit 22, in FIG. 35C. At a glance, the original printed image on the 10 which use different printing mechanisms. A person knowing printing medium 23 shown in FIG. 35B and the copy printed how to tell the difference can readily identify a printed on the printing medium 23' shown in FIG. 35C may seem to document as the original or a copy, by touching the identi be the same. fying information to ascertain whether it is embossed, for Close observation of the media, however, shows a differ example. Copies made with a copying machine are distin ence between the original and the copy. The identifying 15 guishable in the same way. The difference between the image produced in the second area 92 on the original by the original and a copy can easily be overlooked, however, by a serial impact dot matrix printing unit 22 comprises punched person not knowing that any difference exists. Thus the holes, as shown in FIG. 36A. The copy of the identifying difference between the original and a copy can be made image in the second area 94 is not punched but is printed in apparent to intended persons, without making the difference a faint shade of gray, as shown in FIG. 36B. obvious to unintended persons. A high level of document Therefore, in the fourth embodiment, the printing medium security can accordingly be provided. 23 on which the original image was printed can be easily The fifth embodiment is particularly useful when the distinguished from the printing medium 23' on which the identifying information is information Such as a corporate copy was printed by checking whether the identifying infor seal. The serial impact dot matrix printing unit 22 provides mation is printed as a pattern of Small punched holes. The 25 document security by printing and embossing the identify problems associated with unidentified copies can accord ing information on the original document, while the elec ingly be avoided. trophotographic printing unit 72 ensures that the identifying A fifth embodiment of the present invention will now be information is printed with high quality on both the original described, omitting detailed descriptions of aspects of the document and copies thereof, including copies that may be structure, operation, and effects that are the same as in any 30 made Subsequently with a copying machine. of the first to fourth embodiments. A sixth embodiment of the present invention will now be The image forming units of the image forming apparatus described, omitting detailed descriptions of aspects of the in the fifth embodiment have the same arrangement as in the structure, operation, and effects that are the same as in any second embodiment, shown in FIG. 13. The operation and of the first to fifth embodiments. structure of the image forming apparatus 71, including the 35 Referring to FIG. 39, the image forming apparatus 111 structure of the electrophotographic printing unit 72 pro comprises an electrophotographic printing unit 72, which is vided as a first image forming unit, the structure of the serial provided as a first image forming unit, a fixed printing unit impact dot matrix printing unit 22 provided as a second 112, which is provided as a second image forming unit, a image forming unit, and the operation of rollers 24a, 24b, pair of rollers 24a, 24b, and a pair of sensors 25, 26. The 27a, 27b are the same as in the second embodiment. The 40 electrophotographic printing unit 72 has the same structure fifth embodiment addresses the problem of distinguishing an as in the second embodiment. original document printed by the image forming apparatus The sensors 25, 26 detect the position of the printing from copies that may be either printed by the same image medium 23. The rollers 24a and 24b transport the printing forming apparatus or made with a copying machine. medium 23 on the basis of the positions detected by the An exemplary page printed by the fifth embodiment will 45 sensors 25, 26, in the direction shown by the arrow from a now be described. The printing media 23 used in this to b. When the printing medium 23 reaches an appropriate embodiment are cut sheets of plain white paper, as shown in position, the electrophotographic printing unit 72 prints an FIG. 37A. Each sheet has two printed areas 101 and 102, as image on the printing medium 23 according to data shown in FIG. 37B. The document text, date of issuance, (DATA1) received from the host apparatus 11. When the issuer, a serial number, and so on are printed by the 50 printing medium 23 reaches a further appropriate position, electrophotographic printing unit 72 in the first area 101. In the fixed printing unit 112 makes a fixed mark on the the original printout, the identifying information in the printing medium 23. Both the image printed according to second area 102 is printed by both the serial impact dot DATA1 and the mark printed by the fixed printing unit 112 matrix printing unit 22 and the electrophotographic printing can be printed on the same page. unit 72. If further copies are printed by the same image 55 The fixed printing unit 112 in the sixth embodiment will forming apparatus, the identifying information is printed now be further described. Referring to FIGS. 40A and 40B, only by the electrophotographic printing unit 72. the fixed printing unit 112 is a type of Stamping unit A copy printed by the electrophotographic printing unit 72 comprising a plunger with a stamp 113 at its exposed end. has two printed areas 103 and 104 as shown in FIG. 37C. At The fixed printing unit 112 may also comprise an inked a glance, the original printed image on the printing medium 60 ribbon or other means enabling the stamp 113 to print an 23 shown in FIG. 37B and the further copy printed on the inked image on the printing medium 23. Alternatively, the further printing medium 23' as shown in FIG. 37C seem to stamp 113 may only form an embossed image. FIG. 40C be the same. shows an example of a fixed mark that may be formed by the A close observation of the media, however, shows a fixed printing unit 112. difference between the original and the copy. The identifying 65 The structure of the image forming apparatus in the sixth image produced in the second area 102 on the original embodiment will be described with reference to FIG. 41. printing medium 23 is an embossed ink-and-toner image, as This drawing shows that the electrophotographic printing US 7,050,725 B2 19 20 unit 72 comprises an electrophotographic printing controller In step S64-1, the fixed printing controller 114 and media 77 and an electrophotographic printing mechanism 78, and transport system 59 transport the printing medium 23 to the the fixed printing unit 112 comprises a fixed printing con printing position. troller 114 and a fixed printing mechanism 115. The image In step S64-2, the fixed printing controller 114 and fixed forming apparatus 111 also comprises a data receiving unit printing mechanism 115 make the fixed mark on the printing 50 and a media transport system 59. medium 23. The host apparatus 11 creates print data as specified by the Ejection of the printing medium 23 is completed after the operator, and sends the print data to the image forming elapse of time té in FIG. 43 from the completion of the apparatus 111. The print data include instructions for print printing of the fixed mark by the fixed printing unit 112. ing an image in a certain position on the printing medium 23 10 The fixed mark can be used in various ways to distinguish by means of the electrophotographic printing unit 72, and the printing medium 23 on which the original image from may also include instructions for the fixed printing unit 112. copies thereof. For example, the fixed printing unit 112 may The print data have the same structure as in the first be adapted to make an embossed mark: in this case, the embodiment. original will bear an embossed mark and copies made with The data receiving unit 50 receives the print data sent 15 a copying machine will only bear a printed mark. Alterna from the host apparatus 11, distinguishes print data intended tively, the fixed printing unit 112 may be adapted to make for the electrophotographic printing unit 72 from fixed punched holes or other types of marks that cannot be printing instructions intended for the fixed printing unit by faithfully reproduced by a copying machine. If copies are reading the printing unit selection information, sends print made by the image forming apparatus 111 itself, the fixed data to the electrophotographic printing controller 77, and mark can be printed only on the original, and not on the sends fixed printing instructions to the fixed printing con copies. troller 114. A date seal or postmark may be printed as the fixed mark. The electrophotographic printing mechanism 78 and If the fixed mark contains a date, the fixed printing mecha media transport system 59 operate as specified in the print nism 115 should have a dial or some other means with which data sent to the electrophotographic printing controller 77. 25 the operator can manually set a desired date. and an image is printed accordingly on the printing medium In a variation of the sixth embodiment, the fixed mark is 23. Then the fixed printing mechanism 115 and media printed by the serial impact dot matrix printing mechanism transport system 59 operate to print a mark on the printing 56 used in the first to fifth embodiments, instead of the fixed medium 23 if so specified by the instruction data sent to the printing mechanism 115. The fixed printing controller 114 fixed printing controller 114. 30 may store the print data describing the fixed mark internally An exemplary page printed by the sixth embodiment will or may receive the print data from an external Source Such now be described. The printing media 23 used in this as a personal computer or a Smart card. In this variation, embodiment are cut sheets of plain white paper, as shown in accordingly, the fixed printing controller 114 may include a FIG. 42A. Each sheet has two printed areas 121 and 122, as storage unit such as a nonvolatile memory for storing fixed shown in FIG. 42B. The document text, date of issuance, 35 print data, and may operate according to the fixed print data. issuer, a serial number, and so on are printed in the first area In a variation of any of the preceding embodiments, the 121 by the electrophotographic printing unit 72, and the first image forming unit is a thermal printing unit instead of fixed mark is printed in the second area 122 by the fixed an inkjet or electrophotographic printing unit. printing unit 112. Those skilled in the art will recognize that further varia The operation of the image forming apparatus 111 in the 40 tions are possible within the scope of the invention, which sixth embodiment will next be described with reference to is defined in the appended claims. the following drawings. FIG. 43 is a timing diagram illus trating the operation of the image forming apparatus. FIG. What is claimed is: 44 is a flowchart illustrating the operation of the image 1. An image forming apparatus including a first image forming apparatus. FIGS. 45 and 46 are flowcharts illustrat 45 forming unit with a first movable printing head that travels ing Subroutines appearing in FIG. 44. over a printing medium to form a first image and a second In step S61 (FIG. 44), the data receiving unit 50 receives image forming unit with a second movable printing head the print data sent from the host apparatus 11. that travels over the printing medium to form a second In step S62, the data receiving unit 50 sends the print data image, the first and second image forming units forming to the electrophotographic printing unit 72. 50 images by different methods on a single page of the printing In step S63, the electrophotographic printing unit 72 medium, wherein the second image is an identifying image processes the print data and prints the image specified by the and the first image is at least partly different from the print data. identifying image. In step S64, the fixed printing unit 112 prints the fixed 2. The image forming apparatus of claim 1, wherein the mark, if so specified, and the processing ends. 55 identifying image identifies an original image to distinguish The flowchart in FIG. 45 illustrates the subroutine that the original image from copies thereof. carries out step S63 in the sixth embodiment. 3. The image forming apparatus of claim 1, wherein the In step S63-1, the electrophotographic printing unit 72 first image forming unit is an inkjet printing unit and the analyzes the position information in the print data. 60 second image forming unit is an impact printing unit. In step S63-2, the media transport system 59 transports 4. The image forming apparatus of claim 3, also including the printing medium 23 to the printing position. means for transporting the printing medium from the first In step S63-3, the electrophotographic printing controller image forming unit to the second image forming unit, the 77 and electrophotographic printing mechanism 78 print the first image being formed before the second image. image specified by the print data. 65 5. The image forming apparatus of claim 3, also including The flowchart in FIG. 46 illustrates the subroutine that a roller for feeding the printing medium toward the first carries out step S64 in the sixth embodiment. image forming unit and the second image forming unit, US 7,050,725 B2 21 22 wherein the first and second printing units position the first 13. The image forming apparatus of claim 12, wherein image and the second image according to rotation of the one of the first image forming unit and the second image roller. forming unit includes an impact mechanism for forming 6. The image forming apparatus of claim 5, also includ images on multiple-ply pressure-sensitive media. ing: 5 14. The image forming apparatus of claim 12 wherein at a first sensor disposed between the first printing unit and least one of the first image and the second image differs in the roller, for sensing the printing medium; and color from background parts of the page. a second sensor disposed between the first printing unit 15. The image forming apparatus of claim 14, wherein the and the second printing unit, for sensing the printing first image and the second image both differ in color from medium; wherein 10 background parts of the page, the first image forming unit the first printing unit positions the first image according to using a first coloring agent, the second image forming unit the rotation of the roller following sensing of the using a second coloring agent different from the first color printing medium by the first sensor, and ing agent. the second printing unit positions the second image 16. The image forming apparatus of claim 15, wherein the according to the rotation of the roller following sensing 15 of the printing medium by the second sensor. first coloring agent is a toner agent and the second coloring 7. The image forming apparatus of claim 3, wherein the agent is an ink agent. first image overlaps the second image. 17. The image fanning apparatus of claim 12, wherein the 8. The image forming apparatus of claim 7, also including first image forming unit is an electrophotographic printing a data receiving unit for receiving print data with attached unit. selection information and sending the print data to the first 18. The image forming apparatus of claim 12, wherein the printing unit, the second printing unit, or the first and second second image forming unit is a serial impact dot matrix printing units according to the selection information. printing unit. 9. The image forming apparatus of claim 7, wherein at 19. The image forming apparatus of claim 12, wherein at least one of the first image forming unit and the second 25 least one of the first image forming unit and the second image forming unit includes a mechanism that deforms the image forming unit includes a mechanism that deforms the page. page. 10. The image forming apparatus of claim 9, wherein said 20. The image forming apparatus of claim 19, wherein mechanism is an impact mechanism for striking the page. said mechanism is an impact mechanism for striking the 11. The image forming apparatus of claim 9, wherein the 30 page. second printing unit embosses the printing medium. 21. The image forming apparatus of claim 20, wherein the 12. An image forming apparatus comprising: first image forming unit and the second image forming unit a first printing unit for transporting a printing medium form images on mutually reverse sides of the page. and, while transporting the printing medium, forming a 22. The image forming apparatus of claim 20, wherein the first image on the printing medium and fusing the first 35 page includes a first side and a second side, the first iniage image onto the printing medium; forming unit forms an image on the first side of the page, the a second printing unit for forming a second image on the image formed by the first image forming unit differing in printing medium while the first printing unit is forming color from background parts of the first side of the page, and the first image, transport of a part of the printing the second image forming unit forms an image on the first medium on which the second image is formed being 40 side of the page by Striking the second side of the page. halted while the second image is being formed; a slack forming unit disposed between the first printing 23. The image forming apparatus of claim 19, wherein unit and the second printing unit, for forming slack in said mechanism is a punching mechanism for punching the printing medium, the slack forming unit including holes in the page. a first roller that transports the printing medium and a 45 24. The image forming apparatus of claim 19, wherein second roller, said mechanism is a punching mechanism for punching disposed between the first roller and the second printing holes in the page. unit, that turns to reduce the slack and stops turning to increase the slack.