US 20050048403A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2005/0048403 A1 Kuroki (43) Pub. Date: Mar. 3, 2005 (54) PLANOGRAPHIC PRINTING PLATE (57) ABSTRACT MATERIAL AND PLANOGRAPHIC PRINTING PLATE PREPARING PROCESS Disclosed is a planographic printing plate material compris ing a hydrophilic support and provided thereon, a light (75) Inventor: Takaaki Kuroki, Tokyo (JP) sensitive layer and an overcoat layer in that order, Wherein the light sensitive layer contains (a) an alkali soluble poly Correspondence Address: mer, (b) a polymeriZable compound having an ethylenically FRISHAUF, HOLTZ, GOODMAN & CHICK, unsaturated bond, (c) a polymerization initiator, and (d) an PC anionic dye represented by the following formula (1), 767 THIRD AVENUE 25TH FLOOR NEW YORK, NY 10017-2023 (US) Formula (1) (73) Assignee: KONICA MINOLTA MEDICAL & GRAPHIC, INC., Tokyo (JP) (21) Appl. No.: 10/923,415 (22) Filed: Aug. 20, 2004 (30) Foreign Application Priority Data Aug. 29, 2003 (JP) ................................ .. JP2003-306272 Publication Classi?cation (51) Int. Cl? ..................................................... .. G03F 7/00 (52) US. Cl. ............................................................ ..430/300 US 2005/0048403 A1 Mar. 3, 2005 PLANOGRAPHIC PRINTING PLATE MATERIAL there is a method Which increases solubility of light sensitive AND PLANOGRAPHIC PRINTING PLATE layer. Typically, a resin having a high acid value or a PREPARING PROCESS photoinitiator system for accelerating reaction by heating has been studied. HoWever, satisfactory preheating latitude FIELD OF THE INVENTION has not yet obtained considering printing durability. Further, the above negative-Working photopolymeriZation type print [0001] The present invention relates to a planographic printing plate material With high sensitivity Which is capable ing plate material has problem in that sludge is likely to be produced in a developer, and does not have a satisfactory of being exposed With laser, and a process of preparing a planographic printing plate employing the same, and par running property. ticularly to a planographic printing plate material capable of being exposed With loW poWer laser, Which improves stor SUMMARY OF THE INVENTION age stability and preheating latitude, and minimizes sludge, [0006] An object of the invention is to provide a plano and a process of preparing a planographic printing plate graphic printing plate material providing high sensitivity, employing the same. high printing durability, and good preheating latitude, and a process of preparing a planographic printing plate employ BACKGROUND OF THE INVENTION ing the same. [0002] In recent years, as a printing plate for off-set printing, a large number of computer to plate (CTP) systems DETAILED DESCRIPTION OF THE have been developed and put into practical use, Which INVENTION imageWise exposes directly to a planographic printing plate material employing laser light based on digital image data to [0007] The present inventors have studied an extensive study. As a result, they have found that the preheating record an image on the material. As the CTP systems, there latitude is Widened by employing a speci?c anionic dye, are a silver salt system, a radical polymeriZation system and storage stability is greatly improved by employing eosin a thermal system, Which differ in characteristics. having a speci?c structure, and a combined use of a [0003] The radical polymeriZation system has character titanocene compound provides good preheating latitude as istics providing high sensitivity and high printing durability, Well as high sensitivity and printing durability, and com and is Widely applied in printing ?elds such neWspaper pleted the invention. Further, they have found that use of the printing. The general radical polymerization is disclosed in anionic dye in the invention provides a good running prop many literatures such as Japanese Patent O.P.I. Publication erty. No. 10-104835. A composition comprising an arene com [0008] The above object of the invention is attained by the pound as a polymeriZation initiator is disclosed in Japanese folloWing constitution. Patent O.P.I. Publication No. 1-152109. Japanese Patent Publication No. 2755723 discloses, as a composition pro [0009] 1. A planographic printing plate material compris viding high sensitivity and high printing durability, a pho ing a hydrophilic support and provided thereon, a light topolymeriZable composition Which comprises a polymer sensitive layer and an overcoat layer in that order, Wherein binder, a free-radical polymeriZable compound, a photore the light sensitive layer contains (a) an alkali soluble poly duction dye (photo-initiator), and a trihalomethyl compound mer, (b) a polymeriZable compound having an ethylenically and a metallocene compound as another photo-initiator, and unsaturated bond, (c) a polymeriZation initiator, and (d) an discloses in the examples a composition comprising an anionic dye represented by the folloWing formula (1), alcohol soluble eosin, a trihalomethyltriaZine, and a titanocene compound. Acomposition disclosed in this patent document provides excellent sensitivity and printing dura Formula (1) bility, Which is preferred, hoWever, a planographic printing plate material comprising the composition is greatly loWered in storage stability after long term storage, resulting in insuf?cient practical properties. [0004] The radical polymeriZation system generally employs a process comprising exposure, heat treatment, Water Washing, alkali development, and Water Washing in that order. This system is a preferred one to obtain high printing durability by completing the radical polymeriZation. HoWever, When printing plate materials having a different thickness Were processed, the printing plate materials are heated at preheating to different temperature due to the different thickness, producing problem of causing develop ment failure. As the countermeasure, an attempt has been made in Which arrangement of rollers in an automatic processing machine (automatic processor) or pre-determi [0010] Wherein R1 represents a substituted or unsubsti nation (provision) of preheating conditions to each plate tuted alkyl group having a carbon atom number of from 4 to 18, a cycloalkyl group having a carbon atom number of from thickness is examined. 4 to 18, or a substituted or unsubstituted aryl group having [0005] As an effective method to Widen the latitude as a carbon atom number of from 6 to 18; R2 through R11 printing plate materials to various preheating conditions, independently represent a hydrogen atom, a halogen atom, a US 2005/0048403 A1 Mar. 3, 2005 substituted or unsubstituted alkyl group having a carbon [0020] 10. The planographic printing plate material of atom number of from 1 to 6, a cycloalkyl group having a item 9 above, Wherein the light sensitive layer further carbon atom number of from 4 to 6, a substituted or contains a polyhalogenated compound as the polymeriZation unsubstituted aryl group having a carbon atom number of initiator. from 6 to 18 or —N(R12) (R13) in Which R12 and R13 independently represent a substituted or unsubstituted alkyl [0021] 11. The planographic printing plate material of group having a carbon atom number of from 1 to 6, a item 10 above, Wherein the polyhalogenated compound is a cycloalkyl group having a carbon atom number of from 4 to polyhalomethylsulfone, a polyhalomethyl oXadiaZole, or a 6, or a substituted or unsubstituted aryl group having a compound having a polyhaloacetyl structure represented by carbon atom number of from 6 to 18; and Y+ represents a the folloWing formula (2), hydrogen ion, an alkali metal ion or an onium ion. R21—CX2— (c:o) _R22 Formula (2) [0011] 2. The planographic printing plate material of item [0022] Wherein R21 represents a hydrogen atom, a bromine 1 above, Wherein the light sensitive layer contains a metal atom, a chlorine atom, an alkyl group, an aryl group, an acyl locene compound as the polymeriZation initiator. group, an alkylsulfonyl group, an arylsulfonyl group or a [0012] 3. The planographic printing plate material of item cyano group; R22 represents a hydrogen atom or a monova 2 above, Wherein the light sensitive layer further contains a lent organic substituent, provided that R21 and R22 may polyhalogenated compound as the polymeriZation initiator. combine With each other to form a ring; and X represents a bromine atom or a chlorine atom. [0013] 4. The planographic printing plate material of item 3 above, Wherein the polyhalogenated compound is a poly [0023] 12. The planographic printing plate material of any halomethylsulfone, a polyhalomethyl oXadiaZole, or a com one of items 8 through 11 above, Wherein the alkali soluble pound having a polyhaloacetyl structure represented by the polymer has a Weight average molecular Weight of from folloWing formula (2), 15,000 to 500,000, and an acid value of from 30 to 200. R21—CX2— (c:o) _R22 Formula (2) [0024] 13. The planographic printing plate material of any one of items 8 through 12 above, Wherein the alkali soluble [0014] Wherein R21 represents a hydrogen atom, a bromine polymer has repeating a monomer unit having an ethyleni atom, a chlorine atom, an alkyl group, an aryl group, an acyl cally unsaturated bond in an amount of from 5 to 50 mol % group, an alkylsulfonyl group, an arylsulfonyl group or a in the molecule. cyano group; R22 represents a hydrogen atom or a monova lent organic substituent, provided that R21 and R22 may [0025] 14. The planographic printing