Method of making letterpress original plate and letterpress printing plate

Abstract

To provide a method of making a letterpress original plate and a letterpress printing plate improved in electroforming releasability, to solve the problem of strain generated on a duplicate plate caused by strong resistance resulting from the duplicate plate's biting into a convex original plate upon releasing the duplicate plate from the convex original plate by an electroforming method.SOLUTION: In the letterpress original plate for use in duplicating a letterpress printing plate by an electroforming method, a plurality of convex patterns are each disposed on a portion of the surface of the base substrate of the letterpress original plate, and the convex patterns each have a pair of tilting sections tilting from the top of the convex pattern toward the surface of the base substrate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a relief original plate and a relief printing plate surface. [Background technology]

[0002] One method for making a relief original plate is the corrosion process. To use the corrosion process, a pattern is first created using a DTP (Desk Top Publishing) system, which uses a personal computer to integrate all the tasks required for print production, such as typesetting, illustration creation, and layout. The film original plate on which the pattern is output using a laser setter is then inverted and attached to a glass plate, which is then attached to a brass plate to print the pattern. The non-printing areas are then corroded and dissolved using the corrosion platemaking process to form the relief print lines.

[0003] However, the etching process is facing problems such as the discontinuation of production of the photosensitive materials required for the process, making them difficult to obtain, and the use of hazardous chemicals in the process makes the process dangerous and environmentally undesirable.

[0004] In addition, patterns created by the corrosion method are prone to errors in line width and depth due to the unique manufacturing process, and it is technically difficult to guarantee quality, so specialized skills are required.

[0005] Therefore, as an alternative to the corrosion method, there is a cutting method using mechanical engraving. Mechanical engraving is a method in which, after creating an engraving program, the image lines within the printing surface are processed using an end mill to form raised image lines, and a raised master plate is produced. If it is necessary to subsequently produce a duplicate plate from the raised master plate, nickel electroforming is used.

[0006] As a manufacturing method for performing electroforming after mechanical engraving, a method has been disclosed for producing an electroformed mold by an engraving process in which an original mold is automatically engraved with a photograph or the like having varying shading in order to faithfully engrave it into the original mold, an electroformed positive mold creation process in which a positive mold is produced by electroforming using the original mold as the cathode, an electroformed negative mold creation process in which multiple negative molds are produced by electroforming from the electroformed positive mold, and an assembly process in which multiple electroformed negative molds are assembled (see, for example, Patent Document 1).

[0007] However, when peeling off the duplicate plate from the convex master plate by electroforming, there is strong resistance to the adhesion to the convex master plate (100) as shown in Figure 1, which interferes with the peeling ability and causes distortion of the duplicate plate, which ends up being treated as a damaged plate, so there were challenges in reducing costs and workload. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2001-115292 A Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above circumstances, the present invention aims to provide a convex master plate with improved electroforming peelability and a method for producing the same, in order to solve the problem of strong adhesion resistance to the convex master plate, causing distortion of the replica plate when peeling the replica plate from the convex master plate by electroforming. [Means for solving the problem]

[0010] The letterpress original plate of the present invention is a letterpress original plate used to replicate a letterpress printing surface by electroforming, and is characterized in that it has a convex pattern portion on a part of the surface of a base substrate, and has an inclined portion that slopes from the convex portion of the pattern portion toward the surface of the base substrate.

[0011] The method for producing a relief printing plate surface according to the present invention is characterized in that a duplicate plate is produced by electroforming using the above-mentioned relief original plate. Effect of the Invention

[0012] By providing an inclined portion to the convex pattern of the letterpress master, the electroforming peelability when making a duplicate plate from the letterpress master by electroforming can be significantly improved. In addition, by suppressing the occurrence of plate waste, costs and workload can be reduced. [Brief description of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams illustrating the bite resistance that occurs when a duplicate plate is produced from a conventional convex master by electroforming. [Diagram 2] FIG. 2 is a cross-sectional view of a relief precursor according to the present invention. [Diagram 3] FIG. 2 is a diagram showing a first inclination angle (α) and a second inclination angle (β) of an inclined portion of a relief original plate. [Figure 4] FIG. 2 is a cross-sectional view of a relief precursor according to the present invention. [Diagram 5] FIG. 2 is a plan view of a relief precursor according to the present invention. [Figure 6] FIG. 2 is a diagram showing an example of a closed figure according to the present invention; [Figure 7] FIG. 2 is a diagram showing a peeling state when a duplication plate is made from a relief master plate in the present invention. [Figure 8] FIG. 1 is a flow diagram of a method for producing a relief precursor according to the present invention. [Figure 9] 1 is a schematic diagram showing a step of processing a relief precursor by mechanical engraving in a method for producing a relief precursor of the present invention. FIG. [Figure 10] 3 shows a process of replicating a plate in the present invention. [Figure 11] FIG. 2 is a plan view of a relief precursor in an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, a convex original plate and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiment described below, and various other embodiments are included within the scope of the technical idea described in the claims.

[0015] FIG. 2 is a cross-sectional view of a letterpress master plate of the present invention. A letterpress master plate (200) is a master plate that is used to produce a duplicate plate by electroforming as described in the prior art. As shown in FIG. 2, a part of the surface of a base substrate (201) made of a metal material is provided with a convex pattern portion (202) corresponding to a pattern to be printed. In the present invention, the pattern of the convex pattern portion (202) is not particularly limited, but in this embodiment, an example in which the pattern portion (202) has an outer ring pattern (204) and a meaningful information pattern (205) as shown in FIG. 2 will be described. As will be described in detail later, each pattern is composed of convex image lines, and the image line widths may be the same or different, and in this embodiment, a case in which the image line widths are different will be described.

[0016] The letterpress original plate (200) of the present invention has an inclined portion (203) inclined from the convex portion (H) of the convex pattern portion (202) toward the surface of the base substrate (201). In the configuration shown in Fig. 2, the inclined portion (203) of the letterpress original plate (200) is provided as a first inclined portion (203a) having a first inclination angle (α) between the convex portion (H1) of the outer ring pattern (204) and the surface of the base substrate (201). Also, in the configuration shown in Fig. 2, a second inclined portion (203b) having a second inclination angle (β) is provided between the convex portion (H2) of the meaningful information pattern (205) and the surface of the base substrate (201).

[0017] The role of the first inclined portion (203a) having a first inclination angle (α) and the second inclined portion (203b) having a second inclination angle (β) is to reduce the biting resistance to the letterpress master (200) when peeling off the replica plate from the letterpress master (200) by electroforming, and to improve peelability. Therefore, any inclination angle may be used as long as it does not impair peelability due to the biting resistance of the letterpress master. Note that, since a larger inclination angle (α, β) increases the biting resistance of the letterpress master, the inclination angles (α, β) are preferably 80 degrees or less, and more preferably 70 degrees or less. Also, when the inclination angles (α, β) are small, the resistance to the letterpress master plate's bite decreases, but in order to prevent clogging (defective printing due to ink residue or other foreign matter accumulating in the recesses between the image lines) caused by interference with other patterns on the surface of the letterpress plate reproduced using the letterpress master plate, the angle is preferably 10 degrees or more, and more preferably 20 degrees or more. Note that the first inclination angle (α) and the second inclination angle (β) may be the same angle or different angles, and may be designed and processed appropriately so as to prevent the letterpress master plate's bite.

[0018] Fig. 3 is a diagram for explaining the detailed configuration of the first inclination angle (α) and the second inclination angle (β). In the letterpress original plate (200) shown in Fig. 3(a), when a first inclined portion (hereinafter referred to as "1-1 inclined portion (23a1)") having a 1-1 inclination angle (α1) and a first inclined portion (hereinafter referred to as "1-2 inclined portion (23a2)") having a 1-2 inclination angle (α2) are present between the convex portion (H1) of the outer ring pattern (204) and the surface of the base material (201), the 1-1 inclination angle (α1) and the 1-2 inclination angle (α2) may be the same angle or different angles.

[0019] Fig. 3(b) is a diagram showing the configuration of the meaningful information pattern (205), and in the letterpress original plate (200), between the convex portion (H2) of the meaningful information pattern (205) and the surface of the base material (201), there is a second inclined portion (hereinafter referred to as "2-1 inclined portion (23b1)") having a 2-1 inclination angle (β1) and a second inclined portion (hereinafter referred to as "2-2 inclined portion (23b2)") having a 2-2 inclination angle (β2), the 2-1 inclination angle (β1) and the 2-2 inclination angle (β2) may be the same angle or different angles. In addition, in the two convex portions corresponding to the meaningful information pattern (205) shown in Fig. 3(b), the second inclination angles may be the same angle or different angles.

[0020] Fig. 4 is a diagram showing the configuration of a letterpress original plate (200) in which the first inclined portion (203a) and the second inclined portion (203b) are in contact with each other at a position higher than the surface of the base material (201) without providing the surface of the base material (201) between the outer ring pattern (204) and the significant information pattern (205). For example, when the distance between the outer ring pattern (204) and the significant information pattern (205) is short, or when the first inclination angle (α) and the second inclination angle (β) are large to reduce the biting resistance, the configuration shown in Fig. 4 is obtained. Although the relationship between the outer ring pattern (204) and the significant information pattern (205) has been described in Fig. 4, the two convex portions constituting the significant information pattern (205) may have a similar configuration (not shown).

[0021] The material used for the convex original plate (200) is not particularly limited as long as it is a material that can be used in electroforming and can be mechanically engraved, and examples of such materials include brass, nickel, brass, etc. Materials that cannot be used in electroforming include aluminum, zinc, etc.

[0022] Fig. 5 is a plan view showing the configuration of a pattern portion (202) in a letterpress original plate (200). As shown in Fig. 5, as an example, the pattern portion (202) is composed of an outer ring pattern (204) and a meaningful information pattern (205).

[0023] In the letterpress original plate (200) of the present invention, the outer ring pattern (204) constituting the pattern portion (202) is formed of a closed figure consisting of convex image lines. A closed figure here refers to a figure having no end points and a spatially closed area. An example of a closed figure is shown in FIG. 6. As shown in the examples of FIGS. 6(a) to (c), any figure may have a closed line that represents the contour of the figure, such as a circle, polygon, figure, etc. The shape of the outer ring pattern (204) in the present invention is not particularly limited as long as it is a closed figure.

[0024] The meaningful information pattern (205) refers to a convex pattern formed inside the outer ring pattern (204). The meaningful information pattern (205) shown in Fig. 5 is an example of a convex pattern for filling in the entire "sun" design, but there is no particular limitation on the information represented by the meaningful information pattern (205) in the letterpress original plate (200) of the present invention, and it may be any information having meaning, such as letters, numbers, symbols, numbers, designs, designs, illustrations, seal impressions, patterns, etc. Note that patterns such as letters, numbers, designs, etc. may be composed of lines.

[0025] Thus, the letterpress original plate (200) of the present invention is composed of a convex-shaped outer ring pattern (204) and a meaningful information pattern (205) formed inside the outer ring pattern (204), and has a first inclined portion (203a) formed between the outer ring pattern (204) and the surface of the base material (201), and a second inclined portion (203b) formed between the meaningful information pattern (205) and the surface of the base material (201).

[0026] The pattern of the design portion (202) shown in this embodiment is an example. There is no limitation on the type and number of patterns, and even if there are two types of patterns as in this embodiment, the image widths of the convex portions may be the same or different.

[0027] FIG. 7 shows an image of peeling off the copy plate from the letterpress master (200) of the present invention. As mentioned above, in the case of the conventional letterpress master described in FIG. 1, when peeling off the copy plate from the letterpress master (100), the bite resistance to the letterpress master (100) was strong, and a large load was applied. In contrast, as shown in FIG. 7, by providing a first inclined portion (203a) between the outer ring pattern (204) of the pattern portion (202) in the letterpress master (200) of the present invention and the surface of the base substrate (201), and a second inclined portion (203b) between the meaningful information pattern (205) of the pattern portion (202) and the surface of the base substrate (201), the load during peeling can be reduced, and the bite can be alleviated.

[0028] Next, a method for producing a relief printing original plate according to the present invention will be described.

[0029] First, an engraving program for forming a convex pattern portion (202) on a letterpress master plate (200) is created, and then the convex pattern portion (202) is formed on the material to be used as the letterpress master plate by mechanical engraving to produce the letterpress master plate (200) (STEP 1). The engraving tool used for mechanical engraving has a tapered cutting edge.

[0030] As for the taper angle, as mentioned above, the first inclination angle (α) and the second inclination angle (β) are appropriately designed so that the letterpress master (200) does not get stuck when the replica plate is peeled off from the letterpress master (200) by electroforming, and the processing is performed using an engraving bit corresponding to the inclination angles (α, β).

[0031] FIG. 9 shows the trajectory of an engraving tool (T) with a tapered cutting edge when machining a convex pattern portion (202) using an engraving tool (T) in the process of producing a letterpress master plate by mechanical engraving in STEP 1, and, for comparison, the trajectory of an end mill (R) when machining a convex pattern portion (302) using an end mill (R) of conventional technology.

[0032] Fig. 9(a) is a diagram showing the trajectory of the tool when machining a convex pattern portion (102) using an end mill (R), in which the end mill (R) moves the distance between the outer ring (104) and the significant information pattern (105) and between the convex portions of the significant information pattern (105). On the other hand, as shown in Fig. 9(b), when machining a pattern portion (202) of the same shape using an engraving tool (T) with a tapered cutting edge, the amount of machining increases by the amount of the taper, so the movement distance (L2) of the engraving tool (T) is shorter than the movement distance (L1) of the end mill (R) between the outer ring pattern (104) and the significant information pattern (105) shown in Fig. 9(a).

[0033] Next, an intaglio master (300) having a concave pattern (302) is produced by electroforming based on the relief master (200) produced by mechanical engraving (STEP 2). Electroforming is a method of precisely replicating the original relief master (200) by using electrodeposition caused by electrolysis, and refers to a technique such as electroplating in which the surface of a material is coated with a thin metal film. Materials for the intaglio master (300) include nickel, its alloys, or compounds thereof, as well as metals consisting of one of copper, silver, gold, chromium, titanium, iron, and zinc, alloys consisting of two or more of these, or compounds containing at least one of these.

[0034] A schematic diagram of the process of producing an intaglio master in STEP 2 is shown in Figure 10. When a letterpress master (200) shown in Figure 10(a) is replicated by electroforming, an intaglio master (300) shown in Figure 10(b) is produced.

[0035] Next, a letterpress plate surface is produced by electroforming (STEP 3) based on the intaglio original plate (300) produced in STEP 2. A letterpress plate surface (400) having a convex pattern portion (402) is produced from the intaglio original plate (300) having a concave pattern portion (302), and this is used as the printing plate surface to be used for letterpress printing.

[0036] In STEP 3, the process of producing a relief printing surface, as shown in FIG. 10(c), a copy is made by electroforming based on the recessed original plate (300), resulting in the production of the relief printing surface (400) shown in FIG. 10(d).

[0037] Hereinafter, a specific example of a relief printing plate surface produced in accordance with the above-described embodiment of the invention will be described in detail, but the present invention is not limited to this example.

[0038] An embodiment of the relief printing plate (200) of the present invention will be described with reference to FIGS. The convex pattern portion (202) of the letterpress original plate (200) of the embodiment is an example composed of a circular outer ring pattern (204) and a meaningful information pattern (205) of the character "マーク" as shown in FIG.

[0039] The outer ring pattern (204) and the significant information pattern (205) shown in Fig. 11 have the same image width throughout the pattern portion (202), with an image width of 200 µm. The first inclination angle (α) of the first inclined portion (203a) shown in Fig. 2 is 45 degrees, and the second inclination angle (β) of the second inclined portion (203b) is 54 degrees. The height from the surface of the base substrate (201) to the convex portion (H) of the pattern portion (202) is 500 µm.

[0040] In order to process the letterpress master plate (200) having the pattern portion (202) configured as described above, a brass plate was mechanically engraved using an engraving tool corresponding to the first inclination angle (α) and the second inclination angle (β) to produce the letterpress master plate (200). The produced letterpress master plate (200) had improved peelability from the letterpress master plate (200) when the letterpress plate surface (400) was replicated by electroforming, and the occurrence of distortion could be suppressed. [Explanation of symbols]

[0041] 100 convex original plate (conventional technology) 200 letterpress master plates 201 Base Material 202 Pattern section 203 Slope 203a first inclined portion 203b Second inclined portion 204 Outer ring pattern 205 Meaningful Information Patterns 300 Intaglio plate 302 Pattern section (intaglio plate) 400 Letterpress edition 402 Pattern section (relief printing surface) H convex part R End Mill T Tapered Tool

Claims

1. A letterpress original plate used to replicate a letterpress printing surface by electroforming, characterized in that the letterpress original plate has a convex pattern portion on a portion of the surface of a base substrate and has an inclined portion that slopes from the convex portion of the pattern portion toward the surface of the base substrate.

2. 2. A method for producing a relief printing plate surface, comprising the steps of: producing a duplicate plate surface by electroforming using the relief original plate according to claim 1.

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