JP2002187373A - Seamless plate applying photosensitive resin plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin printing plate being a sheetlike printing plate capable of easily forming a sleeve-shaped printing plate without using an adhesive substance, easy to accurately hold the continuity of a printing pattern in a joint part and holding bonding force sufficient to stably perform an ordinary printing process in the joint part. SOLUTION: The side surface of the sheetlike photosensitive resin printing plate is formed into a shape shown by Fig 1 by cutting processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless photosensitive resin printing plate having no seams.

[0002]

2. Description of the Related Art In today's printing field, in order to manufacture a printing plate having a seamless pattern using a photosensitive resin printing plate, a sheet-shaped printing plate having a pattern is wound around a plate cylinder of a printing press. Thereafter, a method is generally used in which a liquid photosensitive resin or the like is applied to a joint portion where both ends of the printing plate are in contact with each other to serve as a bonding agent, and then this is light-cured to prepare a seamless printing plate having no joint. .

[0003]

However, the seamless printing plate obtained by the conventional manufacturing method has various problems as described below. (1) It takes time to make the sheet-shaped printing plate seamless. (2) The bonding strength at the joint is insufficient, and if the completed printing plate is bent or the like, the joint is easily peeled off, and sufficient durability cannot be secured as a printing plate. (3) It is extremely difficult to completely and continuously connect complicated patterns such as fine lines and dots at the joints. (4) Since it is difficult to control the thickness of the plate at the joint portion with high accuracy, a difference in height (uneven thickness of the plate) occurs between the joint portion of the printing plate and other portions, and this is the printing quality such as uneven ink density. Leads to a decline. The present invention overcomes the problems associated with the conventional method of manufacturing a seamless photosensitive resin printing plate as described above, is easy to be seamless, has printing durability, and has the continuity and printing quality of a complicated printed pattern. It is an object of the present invention to provide a photosensitive resin printing plate that does not impair.

[0004]

That is, the sheet-shaped photosensitive resin printing plate of the present invention has both sides of the thickness of the printing plate along the circumferential direction of the printing plate cylinder when the printing plate is wound around the plate cylinder of the printing press. (Hereinafter referred to as side surface M) both have a specific shape,
Thus, a seamless printing plate having printing durability sufficient for practical use can be produced by a very simple operation without using a substance having an adhesive action as in the prior art.

More specifically, the present invention relates to a photosensitive resin printing plate whose thickness side surface along the circumferential direction of the plate cylinder surface when installed on the printing plate cylinder is as shown in FIG. a printing plate upper surface, a printing plate plate contact surface length d, a printing plate lower surface, and a printing plate thickness c.
The shape of both ends of the thickness side surface along the circumferential direction of the printing plate cylinder surface when installed on the printing plate cylinder has a downward taper from the printing plate upper surface to the printing plate upper surface angle α, and the printing plate from the printing plate lower surface. The taper has an upward taper of the lower surface angle β, the two tapers intersect at the printing plate upper depth b, and the angle α, the angle β, the thickness c, and the upper depth d are as shown in the following (formula 1) to formula (4). Wherein the photosensitive resin printing plate is within the range described above. 75 ° <α ≦ 90 ° (Equation 1) 105 ° <β ≦ 150 ° (Equation 2) 0.1 ≦ b / c ≦ 0.6 (Equation 3) A ≦ a ≦ 1.1A (Formula 4) In Formula 4, A: printing plate outer peripheral length = 2π (D + c) (D;
Radius of the printing plate cylinder).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 1 shows the shape of the side surface M at the end of the photosensitive resin printing plate of the present invention. FIG. 2 shows the joining shape of the side surface M when the printing plate is wound around and mounted on a printing press plate cylinder. When the side surface M is shaped as shown in FIG. 1, when it is mounted on the plate cylinder, as shown in FIG. 2, the end of the printing plate is compressed and deformed. The seam can be held in close contact with each other with sufficient strength to withstand the printing operation without using an adhesive substance.

Hereinafter, the photosensitive printing plate of the present invention will be described in detail with reference to FIGS. In FIG. 1, the surface including the length direction indicated by d is a lower surface that is in direct contact with the plate cylinder at the time of printing via a support, a film, and the like as necessary, and the characters and designs to be printed are formed as reliefs. Is located on the back side of the upper surface of the printing plate. When the printing plate is mounted on a printing plate cylinder, the length direction of a in FIG. 1 is along the circumferential direction of the plate cylinder (the length direction of a is orthogonal to the plate cylinder cylinder-axial direction). In this manner is wound around the plate cylinder.

In the present invention, a in FIG. 1; the length of the printing plate outer peripheral length is within the range defined by (Equation 4). If the outer peripheral length a is shorter than this, when the printing plate is mounted on the plate cylinder, both ends of the printing plate cannot contact each other, and a seamless printing plate cannot be formed. Further, when the outer peripheral length a ≦ 1.1A, the joint holding force due to an appropriate elastic repulsion is generated at both ends of the printing plate that has been compressed and deformed in FIG. The seam is not exposed due to the bulge, and the formation of the seamless printing plate becomes easy.

The value of the printing plate upper surface angle defined by α in FIG. 1 is in the range of (Equation 1). Angle α> 75
2 stabilizes the joining of the compression-deformed printing plate ends in FIG. 2, and even when an unexpected external force is applied to the joint portion, the joint portion is not easily displaced.
A stable seamless state can be maintained. further,
At an angle α ≦ 90 °, an appropriate elastic repulsion is generated at both ends of the printing plate that has been compressed and deformed in FIG. 2, and a depression or a bulge is generated at a printing plate joint portion due to an excessive repulsion force. It is easy to form a seamless printing plate without fogging.

Further, the value of the printing plate lower surface angle defined by β in FIG. 1 is in the range of (Equation 2). When the angle β is smaller than this range, the elastic repulsive force generated between both ends of the printing plate that has been compressed and deformed in FIG. 2 becomes too strong, and a depression or a bulge is generated at a printing plate joint portion, and the connecting portion is exposed. And a seamless printing plate cannot be formed. When the angle β is larger than this range, FIG.
In this case, the joint holding force between the both ends of the printing plate is weakened, and the joint portion is depressed after several printing steps, resulting in uneven adhesion of printing ink and the like, which is not preferable.

Finally, b: the depth of the printing plate upper part and c; the ratio of the printing plate thickness b /, indicated by the wavy line in FIG. 1 defined by the intersection of the sides in the printing plate thickness direction determined by each of the angles α and β.
c is in the range of (Equation 3). When the ratio of the two, b / c, is within this range, the joint holding force at the joint portion due to the elastic repulsive force generated at the joint portion at both ends of the printing plate that has been compressed and deformed in FIG. As a result, it is possible to prevent the occurrence of depressions, bumps, deviations, and the like at the joint portions, and to easily maintain a seamless form of the printing plate throughout the printing operation. There is no particular limitation on the photosensitive resin and the support that form the printing plate of the present invention, and the printing plate of the present invention can be formed using commonly used materials. A material having a hardness of 30 to 90 degrees of Shore A and having mechanical properties of tensile elongation at break of 100% or more is preferable because the side M shape processing is easy.

The following two are typical methods for producing the printing plate of the present invention. 1. After preliminarily cutting the side surface M of the printing plate made of a photosensitive resin into the shape of the present invention, and exposing, washing, drying and post-exposing the resin plate according to a conventional method, the photosensitive resin printing is performed. Form a plate. 2. A printing plate having a normal shape made of a photosensitive resin is exposed, washed, dried, and post-exposed by a conventional plate-making apparatus, and then cut with heat, or a special knife, or a laser beam or the like to cut the printing plate side surface M. Cut to form the shape of the present invention. The printing plate equipped with the photosensitive resin printing plate molded by any of the above methods, while maintaining the continuity of the pattern by adjusting the displacement of the joint portion in the same manner as a normal sheet printing plate, printing It can be mounted on a printing plate cylinder, for example, by wrapping a printing plate around the cylinder of a printing plate cylinder by pasting it on the cylinder with double-sided tape.

Hereinafter, the molding method of the photosensitive printing plate of the present invention will be described in more detail with reference to examples.

Example 1 A photosensitive resin printing plate according to the present invention having the following specifications and having a continuous pattern of solid white portions (no solid seams) on a plain single-sided tape was formed by the above-mentioned production method 2. Printing plate length; a = 42.4 cm printing plate outer circumference; A = 42.0 cm printing plate upper depth; b = 0.4 mm printing plate thickness; c = 1.70 mm printing plate upper surface angle; α = 85 ° printing plate lower surface Angle; β = 130 °

A negative photosensitive film having a predetermined design is exposed and cured by a conventional plate-making method to produce a sheet-shaped photosensitive resin printing plate having a printing plate length of 1.1a = 46.64 cm. Set the fusing cutter at a set temperature of 15
It was used at 0 ° C. and processed into the shape of the side surface M as shown in FIG. 1 by the following procedure. (A) First, in FIG. 1 obtained by calculation from the values of b, c, α, and β, from the point p in FIG. 1 determined by the length of d (the printing plate cylinder contact surface) and the value of the printing plate length a. At an angle β, chamfer cutting is performed using a thermal fusing cutter. Usually, the point p is determined such that the middle point of d is located at the center of the symbol. (B) Next, chamfering and cutting are performed again by using a thermal fusing cutter at an angle α from the position of the printing plate edge in FIG. 1 determined from the value of a. The other end is also chamfered by the same operation to obtain a printing plate having a cross-sectional shape M shown in FIG.

The printing plate thus obtained was mounted on a flexographic printing press plate cylinder by the following operation to print a continuous pattern of solid white portions (no solid seams). First, a double-sided tape for mounting a plate was stuck to a flexographic printing plate cylinder, and then the printing plate was stuck accurately so that both ends contacted as shown in FIG. To register the plate accurately, attach a register mark for registration to the edge of the plate material, and use an optical lens to place the register mark of the plate around the plate cylinder at the same position at the joint of the pattern with an optical lens. The plate was stuck to. After the printing plate cylinder having the printing plate attached thereto was mounted on the flexographic printing press in a predetermined manner, printing was started. After printing 60,000 meters, the joints of the printing plates were observed, but the joints did not undergo any deformation such as bulging, depressing, and misalignment of the printing plates.
No discontinuity was observed in the pattern corresponding to the printing plate joint.

[0016]

Example 2 The sheet-shaped photosensitive flexo resin before exposure and curing was heated to a temperature of about 25 by the hot fusing cutter used in Example 1.
Except for obtaining a printing plate by exposure hardening after performing chamfering cutting processing at 0 ° C., forming a sheet-shaped flexographic printing plate having a side surface M, mounting the printing plate on a printing machine, according to Example 1. And printing. After printing 60000 meters, the printing plate joint was observed, but no deformation such as uplift, depression, and displacement of the printing plate occurred at the joint, and the portion corresponding to the printing plate joint also appeared on the printing medium. No discontinuity was observed in the pattern of.

[0017]

Comparative Example 1 A printing plate having a cross section M defined by the same values of α, a, b, and c as in Example 2 except that β = 90 ° was formed by cutting described below. except,
Printing plate molding and printing were performed in the same manner as in Example 2. (C) First, in FIG. 1 obtained by calculation from the values of b, c, α, and β, from the point p in FIG. 1 determined by the length of d (the printing plate cylinder contact surface) and the value of the printing plate length a , B are cut vertically to the level of the wavy line in FIG. (D) Next, chamfering is performed along a line determined from the value of a and connecting the end of the printing plate and the point of the cut end in FIG. After printing 20 mails, the printing plate joints were observed. However, along the joints, ups and downs of the printing plates were observed at several places, and the seamless printing plates had an incomplete shape.

[0018]

By using the sheet-shaped photosensitive resin printing plate according to the present invention, it is possible to easily form a seamless sleeve-shaped printing plate in a short time without using an adhesive substance. In addition, it is easy to accurately maintain the continuity of the printed pattern at the joint. The joint portion of the sleeve-shaped printing plate holds a bonding force sufficient to stably perform the printing process.

[Brief description of the drawings]

FIG. 1 is a schematic view of a printing plate side surface M of the present invention before being mounted on a printing plate cylinder.

FIG. 2 is a schematic view of a printing plate side surface M of the present invention when mounted on a printing plate cylinder.

[Explanation of symbols]

a printing plate length b printing plate upper depth c printing plate thickness d printing plate cylinder contact surface length α printing plate upper surface angle β printing plate lower surface angle p printing plate cylinder contact surface length d, printing plate length a, angle α and angle Point determined by the value of β

Claims (1)

[Claims] 1. A photosensitive resin printing plate having a printing plate upper surface having a printing plate length a, a printing plate lower surface having a printing plate cylinder contact surface length d, and a printing plate thickness c, when installed on the printing plate cylinder. The shape of both ends of the thickness side surface along the printing plate cylinder surface circumferential direction has a downward taper from the printing plate upper surface to the printing plate upper surface angle α, and has an upward taper from the printing plate lower surface to the printing plate lower surface angle β. The taper has a shape intersecting at the printing plate upper depth b, and the angle α, the angle β, the thickness c, and the upper depth d are within the ranges of the following (formula 1) to formula (4). Photosensitive resin printing plate. 75 ° <α ≦ 90 ° (Equation 1) 105 ° <β ≦ 150 ° (Equation 2) 0.1 ≦ b / c ≦ 0.6 (Equation 3) A ≦ a ≦ 1.1A (Formula 4) In Formula 4, A: printing plate outer peripheral length = 2π (D + c) (D;
Radius of the printing plate cylinder).