United States Patent (19) 11 Patent Number: 4,796,328 Horie (45) Date of Patent: Jan. 10, 1989 54 ERASER Attorney, Agent, or Firm-Hedman, Gibson, Costigan & Fumio Horie, Tokyo, Japan Hoare 75 Inventor: 57 ABSTRACT 73) Assignee: Horie Sangyo Kabushiki Kaisha, Tokyo, Japan An eraser capable of erasing characters and the like written on paper with a ball-point pen, fountain pen, 21 Appl. No.: 133,565 typewriter, word processor, color pencil or the like. 22 Filed: Dec. 16, 1987 The eraser has an integral structure composed of plural types of eraser pieces having different hardnesses and (30) Foreign Application Priority Data an abrasive material, the eraser pieces and the abrasive Dec. 18, 1986 JP Japan ................................ 61-302631 material existing respectively in a particulately dis 51) Int. Cl. .............................................. B43L 19/00 persed state. A method for manufacturing such eraser 52 U.S. C. ...................................................... 15/424 comprises steps of kneading plural types of major eraser 58 Field of Search .......................................... 15/424 materials which have been previously vulcanized and shaped at need with an abrasive material and vulcaniz 56) References Cited ing and shaping the resulting mixture. These plural U.S. PATENT DOCUMENTS types of major eraser materials are such that erasers 328,778 10/1885 Holton .................................. 5/424 having different hardnesses can be produced if each of the major eraser materials is either vulcanized or heated FOREIGN PATENT DOCUMENTS and shaped alone and that particles of the major eraser 1443536 5/1966 France .................................. 15/424 materials exist independently from one another even if 6035063 9/1976 Japan .... ... 15/424 these materials are kneaded. 2042898 2/1987 Japan ..................................... 15/424 Primary Examiner-Chris K. Moore 4 Claims, 3 Drawing Sheets U.S. Patent Jan. 10, 1989 Sheet 1 of 3 4,796,328 U.S. Patent Jan. 10, 1989 Sheet 2 of 3 4,796,328 U.S. Patent Jan. 10, 1989 Sheet 3 of 3 4,796,328 4,796,328 1. 2 need with an abrasive material, and vulcanizing and ERASER shaping the resulting mixture, said plural types of major eraser materials are such that erasers having different BACKGROUND OF THE INVENTION hardnesses can be produced if each of said plural types This invention relates to an eraser, ability of which 5 of major eraser materials is either vulcanized or heated for erasing characters and the like on a paper written and shaped alone and that particles of said plural types with ball-point pen, fountain pen, typewriter, word of major eraser materials exist independently from one processor, color pencils or the like is improved, and to another even if these materials are kneaded. a method for manufacturing such improved eraser. According to the eraser of the present invention, A so-called sand-containing eraser has been hereto O when the eraser is pressed against the surface of a paper fore known as an eraser for erasing characters and the to be erased, soft eraser pieces in said eraser deform in like written on a paper with ball-point pen, fountain pen conformity with a minute irregularity on said paper or the like. A conventional sand-containing eraser is surface resulting in close contact of the entire eraser manufactured in such a manner that a factice (white with paper. In this case, the abrasive material is forcibly factice), a plasticizer, and a mineral oil are mixed homo 15 pressed against the paper surface by means of hard geneously with rubber or plastic, a major component, to eraser pieces to scrape out ink bonded on said paper which is added an abrasive material having a particle surface. Thus, even if there is a minute irregularity on size of...about 150 emery, carborundum (black silicon the paper surface, said paper surface can be sufficiently carbide) or the like, the resulting admixture is kneaded rubbed with the eraser according to the invention along by the use of rolls or the like, and the product thus 20 the irregular surface thereof, so that only the ink can be kneaded is either vulcanized or heated and shaped. removed without substantial damage of the paper sur The structure of the shaped eraser is shown in FIG. 2 face. wherein particles of an abrasive material 12 are dis Furthermore, said improved eraser can be obtained in persed and included in a homogeneous major eraser accordance with the manufacturing method of the pres material 10. 25 ent invention. In said conventional sand-containing eraser, if the major eraser material 10 is a soft material, such major BRIEF DESCRIPTION OF THE DRAWINGS eraser material does not present suitable stiffness to FIG. 1 is an enlarged sectional view showing an sustain particles of the abrasive material 12 as shown in example of the eraser according to the present inven FIG. 3 in the case when the eraser itself is pressed 30 tion; against the surface of a paper 14. Thus, such eraser FIG. 2 is a sectional view as well as a partially en cannot scrape the ink 16 bonded to the paper surface 14 larged view thereof each showing a conventional sand therefrom so that such conventional eraser has poor erasing ability. containing eraser; On the other hand, if the major eraser material 10 is a 35 FIGS. 3 and 4 are sectional views each illustrating a hard material, such hard major eraser material 10 can state of a paper in the case where the sand-containing not be in close contact with the paper surface 14 as eraser of FIG. 2 is pressed against the surface of the shown in FIG. 4. Accordingly, if there is a minute irreg paper; and ularity on the paper surface 14, particles of the abrasive FIG. 5 is a sectional view illustrating a state of a material 12 included in such hard eraser cannot fit into paper in the case where the eraser of FIG. 1 is pressed the minute irregularity so that the abrasive material against the surface of the paper. particles 12 cannot scrape off the ink 16 on the paper DESCRIPTION OF PREFERRED surface 14. In this case, it is required to scrape off the EMBODIMENTS paper 14 itself up to such a depth corresponding to that where the ink 16 exists, so that there is such a disadvan 45 An embodiment of the eraser according to the pres tage that the paper 14 is damaged by such hard eraser in ent invention is shown in FIG. 1 in an enlarged manner the case where a soft paper is used, whilst if a hard wherein an example where the eraser itself is prepared paper is employed, the paper 14 cannot be scraped off from three types of erasers. More specifically, this by the eraser so that the ink 16 on the paper surface eraser is integrally composed of soft eraser pieces 20, remains unerased. 50 medium eraser pieces 22, hard eraser pieces 24, and an In view of the above, the present invention contem abrasive material 26 in a particulately dispersed form. plates to eliminate disadvantages involved in the above When the eraser is pressed against the surface of a described prior art and to provide an improved eraser paper, the front of the eraser comes into close contact through the use of which damage of a paper to be with the paper surface 28 as a result of deformation of erased decreases, besides erasing ability of the eraser is 55 the soft eraser pieces 20 in conformity with a minute elevated, as well as a method for manufacturing such unevenness of the paper surface 28 as shown in FIG. 5. improved eraser. At the same time, the abrasive material 26 is strongly pressed upon the paper surface 28 by means of the hard SUMMARY OF THE INVENTION eraser pieces 24 to scrape off ink 30 which has adhered The present invention relates to an eraser having an to the paper surface 28. Thus, even if there is a minute integral structure composed of plural types of eraser unevenness on the paper surface 28, the surface of the pieces having different hardnesses and an abrasive mate paper can be rubbed with the eraser along the uneven rial, said eraser pieces and said abrasive material existing ness thereof, so that only the ink 30 can be removed in a particulately dispersed state. without damaging significantly the paper surface 28. Furthermore, the present invention relates also to a 65 method for manufacturing an eraser comprising the EXAMPLE 1. steps of kneading plural types of major eraser materials An example of a method for manufacturing the eraser which have been previously vulcanized and shaped at shown in FIG. 1 will be described hereinbelow. 4,796,328 3 4. In Example 1, three types of materials for the eraser, ball-point pen on the paper and the dissolved ink blots i.e. hard, medium, and soft materials are used as the on this paper. However, when ingredient A is kneaded major eraser materials. Material 1 (the eraser 20) is a with the other ingredients in material 1, the ingredient particularly soft material, material 2 (the eraser 22) is A is dispersed into the material 1. Thus, ingredient A one having substantially the same hardness with that of 5 contributes to release rapidly the ink adhered closely to ordinary raw rubber, and material 3 (the eraser 24) is a the surface of a paper, when the paper surface is rubbed hard material. In the case where only two types of hard with such an eraser containing the material 1 after vul and soft materials are used and in addition, there is a canization.