JP3606286B2 - Topographic printing device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention, by attaching the ink to the convex portion of the plate having a surface roughness, but regarding the letterpress equipment to transfer the ink to the printing medium.
[0002]
[Prior art]
FIG. 3 is a diagram showing a schematic configuration of a conventional relief printing apparatus.
A plate 16 a is attached to the plate cylinder 16. The plate 16a has surface irregularities formed so that the image line portion becomes a convex portion and the non-image line portion becomes a concave portion. As the material of the plate 16a, zinc, copper, resin, or the like is generally used. The plate 16a is produced by applying a photosensitive solution to the plate surface, baking a negative, etc., and dissolving the non-image area with a nitric acid corrosive solution or the like.
[0003]
When ink is supplied from the ink base roller 12 on the ink key 11 side to the calling roller 13, the ink is kneaded by the plurality of kneading rollers 14 and then supplied to the ink forming roller 15. Here, the reason why the ink is kneaded by the plurality of kneading rollers 14 is to obtain various physical properties of the ink necessary for printing. And ink adheres to the convex part of plate 16a. The impression cylinder 17 applies a printing pressure by pushing the plate cylinder 16 through the printing substrate 20. Thereby, the ink is transferred to the printing substrate 20 and printing is performed.
[0004]
[Problems to be solved by the invention]
However, the above-described conventional relief printing apparatus has the following problems.
FIG. 4 is a diagram illustrating in detail the contact state between the printing plate 16a and the printing substrate 20 during printing. In general, it is difficult to maintain the convex surface of the plate 16a with high accuracy. Therefore, a high printing pressure is applied in order to completely transfer the surface irregularities formed on the plate 16 a to the printing substrate 20. As a result, there is a problem in that the ink attached to the surface of the convex portion of the plate 16a protrudes around the convex portion (outside the convex surface) and a marginal zone occurs in the printed matter. This marginal zone gives a feeling of bordering characters and the like, and is preferred in some cases, but there is a problem that the dot diameter changes in the dot pattern.
[0005]
The present invention has been made to solve the above-described problems, and an object thereof is to improve the print quality by suppressing the occurrence of a marginal zone.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 includes a plate cylinder, a plate provided on an outer periphery of the plate cylinder and having surface irregularities, and an impression cylinder that presses the plate through a printing object. A printing plate printing apparatus that deposits ink on the convex portion of the plate and transfers the ink to the printing object, and reduces printing pressure at the outer edge of the convex portion of the plate. The printing pressure reducing means is a cushion layer provided on the outer peripheral portion of the impression cylinder and elastically deformed by a pressing force during printing, and the cushion layer has an uneven portion on the inner peripheral surface side. An area on the outer peripheral surface side of the convex portion of the cushion layer overlaps with a central portion of the convex portion of the plate during printing, but does not overlap with an outer edge portion of the convex portion of the plate. Device.
According to a second aspect of the present invention, in the relief printing apparatus according to the first aspect, the region on the outer peripheral surface side of the convex portion of the cushion layer overlaps with an area of 80 to 90% of the convex portion of the plate. This is a relief printing apparatus.
[0009]
[Action]
According to the present invention, when the printing object is pressed against the plate by the impression cylinder, the ink attached to the convex portion of the plate is transferred to the printing object. In that case, the pressure which acts on the outer edge part of the convex part of a plate becomes smaller than the pressure which acts on the center part of a convex part. Accordingly, it is possible to reduce the protrusion of ink around the convex portion (generation of a marginal zone). And at the time of printing, the pressure of the outer edge part of the convex part of a plate reduces by the effect | action of a cushion layer.
Further, an area of 80 to 90% of the convex portion of the plate overlaps with the convex portion of the cushion layer. Accordingly, it is possible to reduce the occurrence of the marginal zone while maintaining the entire appropriate printing pressure.
[0010]
【Example】
Hereinafter, an embodiment of a relief printing apparatus and a relief printing method according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an embodiment of a relief printing apparatus according to the present invention. The present invention is different from the relief printing apparatus shown in the conventional example in that a cushion layer 18 is provided on the impression cylinder 17. Other configurations are the same as those in FIG.
The cushion layer 18 is attached to the outer periphery of the impression cylinder 17. The cushion layer 18 is formed of resin, rubber, or the like, and has a hardness of, for example, a Shore D hardness of about 30 ° or a Shore A hardness of about 80 °. Therefore, the cushion layer 18 has a certain degree of elasticity.
[0011]
Concave and convex portions are formed on the inner peripheral surface side of the cushion layer 18. The region on the outer peripheral surface side of each convex portion of the uneven portion overlaps with each convex portion of the plate 16a at the time of printing, and is included in the region of the convex portion of the overlapping plate 16a, for example, It has an area of about 80 to 90% of the area.
[0012]
As a method for producing the cushion layer 18, for example, when exposing the photosensitive resin, the film used at the time of printing the printing plate is turned over so as to have a convex portion smaller than the convex portion of the actual plate 16 a. To form. Alternatively, when exposing the photosensitive resin, a film having a convex portion reduced by turning the film upside down is used. Alternatively, when performing a printing plate by a digital method, a convex portion smaller than the printing plate is formed by correcting image data.
The cushion layer 18 formed in this way is attached to the impression cylinder 17 so that the impression cylinder 17 side is the uneven side. Also, positioning is performed using a register mark or the like.
[0013]
FIG. 2 is a diagram illustrating in detail the contact state between the printing plate 16a and the printing substrate 20 during printing. In FIG. 2, at the time of printing, the cushion layer 18 is pressed against the plate 16a through the printing substrate 20 in a state where ink adheres to the convex portion of the plate 16a. Here, although the convex part of the plate 16a and the convex part of the cushion layer 18 overlap, the region of the convex part of the cushion layer 18 is arranged in the region of the convex part of the plate 16a in the thickness direction. That is, the central portion of the convex portion of the plate 16 a overlaps with the convex portion of the cushion layer 18, but the outer edge portion of the convex portion of the plate 16 a does not overlap with the convex portion of the cushion layer 18. Accordingly, the pressure acting on the outer edge of the convex portion of the plate 16a is reduced. As a result, the ink hardly protrudes from the periphery of the convex portion of the plate 16a, and the occurrence of the marginal zone is reduced.
[0014]
【The invention's effect】
According to the present invention, it is possible to reduce the protrusion of ink around the convex portion of the plate (generation of a marginal zone). Accordingly, the print quality can be improved.
Further, it is possible to reduce the occurrence of the marginal zone while maintaining the entire appropriate printing pressure.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an embodiment of a relief printing apparatus according to the present invention.
FIG. 2 is a diagram showing in detail a contact state between a printing plate 16a and a printing substrate 20 during printing.
FIG. 3 is a diagram showing a schematic configuration of a conventional relief printing apparatus.
FIG. 4 is a diagram showing in detail a contact state between a printing plate 16a and a printing substrate 20 during printing.
[Explanation of symbols]
16 Plate cylinder 16a Plate 17 Impression cylinder 18 Cushion layer 20 Print substrate

Claims (2)

Plate cylinder,
A plate provided on the outer periphery of the plate cylinder and having surface irregularities;
An impression cylinder that presses the plate through a printing object;
A letterpress printing apparatus that attaches ink to the convex portions of the plate and transfers the ink to the printing object,
Printing pressure reducing means for reducing the printing pressure of the outer edge of the convex portion of the plate;
The printing pressure reducing means is a cushion layer provided on the outer periphery of the impression cylinder and elastically deformed by a pressing force during printing,
The cushion layer has an uneven portion on the inner peripheral surface side,
A region on the outer peripheral surface side of the convex portion of the cushion layer overlaps with a central portion of the convex portion of the plate during printing, but does not overlap with an outer edge portion of the convex portion of the plate. . In the relief printing apparatus according to claim 1 ,
An area on the outer peripheral surface side of the convex part of the cushion layer overlaps with an area of 80 to 90% of the convex part of the plate.

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