JP4146946B2 - Method for producing photosensitive lithographic printing plate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive lithographic printing plate, and more particularly to a method for producing a photosensitive lithographic printing plate that is suitably used for newspaper printing without causing stains on the periphery of a printed material.
[0002]
[Prior art]
At present, the mainstream of photosensitive lithographic printing plates is an aluminum plate as a support and a photosensitive layer provided thereon. This photosensitive lithographic printing plate, so-called PS plate, is obtained by subjecting a sheet-like or coil-like aluminum plate to various surface treatments such as graining, anodizing, hydrophilization treatment, and the like. At the time of use, the original image film is brought into intimate contact with the photosensitive layer, irradiated with actinic rays such as ultraviolet rays, and then subjected to a development treatment to obtain a printing plate.
[0003]
When printing using the printing plate obtained in this way, the edge of the printing plate (the edge along the edge) is printed on paper smaller than the printing plate size on a normal sheet-fed printing press. There is no problem if the portion corresponding to the edge does not become the printing surface. For example, when printing continuously on roll paper using a rotary press such as newspaper printing, When the width of the printing plate is smaller than the width of the paper, the printing ink adhering to the end portion is transferred to the paper, and this appears as linear stains on the end portion of the newspaper. This stain may be referred to as edge stain (frame stain).
[0004]
As a method for preventing such contamination, for example, Japanese Patent Publication No. 57-46754 discloses a method of providing a notch along the edge of the edge of an aluminum support, or Japanese Patent Laid-Open No. 7-32758 discloses aluminum. A method has been proposed in which the edge of the support is bent to the opposite side of the printing surface.
Japanese Patent Publication No. 62-61946 discloses a method of applying an end face of an aluminum plate with a desensitizing solution containing a hydrophilic organic polymer compound, and Japanese Patent Application Laid-Open No. 9-211843 discloses two opposing sides or A method of providing a hydrophilic coating layer made of a metal oxide obtained by hydrolysis and polycondensation of an organometallic compound or an inorganic compound on the side surfaces of the four photosensitive layers has been proposed.
Furthermore, Japanese Patent Laid-Open No. 10-35130 discloses that the gap between the upper blade and the lower blade of the slitter device is set to a question of 30 to 100 microns and cut, and the maximum average value of the roughness of the cut surface is obtained. Has been disclosed such that is from 1.2 microns to 12 microns.
[0005]
However, the method of providing a notch along the edge of the edge of the aluminum support described above, or the method of making the edge of the aluminum support bent to the opposite side of the printing surface, both of the edge of the aluminum support. This is a processing of the part, and the cut surface of the slitted aluminum support is not processed at all, and the stain due to the ink adhering to this part cannot be eliminated.
In addition, when a desensitizing solution or a hydrophilic material is applied to the end face, the desensitizing solution or the like is washed away during the development process, and again, the desensitizing solution such as an aqueous gum arabic solution is used. Is desensitized. At this time, if the end surface, which is a cut surface, is cut cleanly and flat like a mirror surface, the desensitizing oil will bounce off or flow down, and the end surface cannot be covered sufficiently. The oiliness is impaired and stains are likely to occur during printing.
Furthermore, in the method of cutting with a gap between the upper and lower blades of the slitter, it is very difficult to set the gap between the upper and lower blades in the micron order, and it is always unstable and workability is improved. For this reason, it is difficult to produce a cut surface having a certain range of roughness, either a very flat surface or an extremely rough surface. If the cut surface is cut and flat, the water retention of the surface becomes poor and the surface tends to become dirty. Conversely, if the surface is extremely rough, ink tends to get tangled on the surface.
[0006]
[Problems to be solved by the invention]
Under such circumstances, the present invention provides a photosensitive lithographic printing plate that is excellent in workability by a simple method and that does not cause frame stains.
In addition, an electrical signal for conveying the plate or bending the plate part of the plate may be activated by contact between the plate end surface and the positioning pin. Is an insulating material such as an aqueous solution of gum arabic, and when it is completely covered, electricity cannot be conducted and a conduction failure may occur, but a printing plate capable of preventing the conduction failure beforehand is provided.
[0007]
[Means for Solving the Problems]
The present invention provides a photosensitive lithographic printing plate characterized in that after the photosensitive lithographic printing plate is cut into a predetermined size with a slitter having at least one pair of cutting blades, the cut surface is grained. The cut surface is grained to the same roughness as the support surface, the center line average roughness (Ra) of the cut surface is 0.2 to 0.7 μm, and the maximum height (Rmax) Is 12 μm or less, and provides a photosensitive planographic printing plate characterized by imparting water retention to the cut surface and preventing poor conduction. Further, the present invention provides a method for producing a photosensitive lithographic printing plate, characterized in that immediately after cutting the cut surface, each sheet is immediately grained one by one, or a plurality of sheets are laminated and then the cut surfaces are grained. is there.
[0008]
The photosensitive printing plate of the present invention makes a flat cut surface by slitter cutting, and then roughens the cut surface to the same roughness as the surface, making it desensitized like gum application in an automatic processor. It is easy to coat the liquid and has an end face with good water retention even during printing. As a result, there is provided a photosensitive lithographic printing plate capable of providing a printing plate particularly suitable for newspaper printing without causing stains around the printed material.
Further, the photosensitive printing plate of the present invention has a grained surface and is uneven, so that the head of the grain protrudes over the application surface of the gum solution, etc., so that the positioning pin contacts there As a result, electricity is conducted, and poor conduction can be prevented.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a photosensitive lithographic printing plate according to an embodiment of the present invention will be described with reference to the drawings.
When the photosensitive lithographic printing plate is cut with a slitter device, the photosensitive lithographic printing plate may be slit in a horizontal state or in a vertical state, but FIG. 1 uses a slitter device 2, It is sectional drawing which cuts the photosensitive lithographic printing plate 1 in a horizontal state.
This slitter device 2 is provided with cutting machines 3 and 4 at the top and bottom, and the upper cutting machine 3 is provided with a pair of left and right upper cutting blades (upper blades) 3b and 3c supported by a rotating shaft 3a. Further, the rotating shaft 4a of the lower cutting machine 4 is provided with lower cutting blades (lower blades) 4b and 4c corresponding to the upper cutting blades 3b and 3c. The upper cutting blades 3b and 3c and the lower cutting blades 4b and 4c are rotated in opposite directions. The photosensitive lithographic printing plate 1 in which the photosensitive layer A is coated on the aluminum support 1a is passed between the upper cutting blades 3b and 3c and the lower cutting blades 4b and 4c and cut into a predetermined width.
[0010]
When the upper cutting blades 3b and 3c are arranged so as to be outside the portion D that is the product of the photosensitive lithographic printing plate 1 with respect to the lower cutting blades 4b and 4c, In some cases, the edge of the front or both sides is crushed and has a curved surface, or the edge may bend toward the back as a whole, but in either case there is almost no burr on the surface, and during printing This is a preferable arrangement method because it prevents ink from accumulating in the edge.
[0011]
The present invention is characterized in that a cut surface (end surface) 11 obtained by cutting a photosensitive lithographic printing plate with the slitter device 2 is grained (polished).
When the cut surface is grained (polished), even the surface of the aluminum support or part of the front and back edges may be grained (polished). Further, when the edge is crushed as described above or is bent in the direction of the back surface, even that portion may be polished. However, this does not impair the object effect of the present invention. In this case, the photosensitive layer at the edge of the surface may be polished and removed, but there is no problem in this case.
[0012]
Graining (polishing) in the present invention is performed by continuously cutting a photosensitive lithographic printing plate with a slitter and then immediately graining or cutting the photosensitive lithographic printing plate, and then stacking a large number of photosensitive lithographic printing plates. There is a method of graining (polishing) the end face in a state.
[0013]
Graining (polishing) methods include: wire brush, nylon brush, nylon brush with abrasive grains, metal file, paper file, buff, abrasive buff, grindstone, grinding stone bar, etc. There are methods such as rubbing mechanically or manually, or etching the end face with corrosive chemicals, but it is not limited thereto.
In the case of this graining (polishing), it is more preferable that the polishing is not only in one direction but also in the vertical and horizontal directions or the cloth is polished into a fine grain.
[0014]
The photosensitive lithographic printing plate of the present invention has an aluminum plate as a support and a photosensitive layer provided thereon, and the roughness of the grained (polished) cut surface (end face) is the same as that of the support surface. In order to maintain the same water retention, it is desirable that the surface has the same roughness as the support surface.
When this roughness is expressed by the method defined in JIS-B0601-1982, the center line average roughness (Ra) is preferably 0.2 to 0.7 μm, more preferably 0.3 to 0.6 μm. And the maximum height (Rmax) is preferably 12 μm or less. If Ra is less than 0.2 μm, the surface becomes too flat, the coverage of gum solution, etc. and water retention during printing tend to be poor, and poor electrical conductivity tends to occur. If it exceeds 0.7 μm, the end face becomes rough. This is not preferable because the ink at the time of printing easily accumulates in the portion and becomes dirty easily. In addition, when Rmax exceeds 12 μm, the end face becomes too rough, and it tends to become dirty.
[0015]
FIG. 2 is manufactured by slitting a wide photosensitive lithographic printing plate 1 using a slitter device 5 using four pairs of upper and lower pair of cutting blades, and simultaneously cutting two portions D as products. It is a schematic diagram. In such a case, an unnecessary portion E is generated in the central portion and both sides.
[0016]
The photosensitive lithographic printing plate of the present invention comprises an aluminum plate as a support and a photosensitive layer provided thereon.
The surface of the aluminum support is subjected to a graining process in order to improve adhesion with the photosensitive layer and to improve water retention.
This graining treatment is generally performed by graining (also called polishing or roughening) by a mechanical method or an electrical method, by chemical etching, or a combination of these treatments. The average roughness Ra of the aluminum support surface at this time is generally 0.2 to 0.7 μm, more preferably 0.3 to 0.6 μm, and the maximum height Rmax is preferably 12 μm or less. . If Ra is 0.2 μm or less, the water retention of the surface and the adhesion to the photosensitive layer will be poor, and the residue of the photosensitive layer will easily remain in the grain of more than 0.7 μm, resulting in scumming during printing. It is not preferable because it becomes easy to do. Also, soiling is likely to occur when Rmax is 12 μm or more.
[0017]
After graining as described above, anodization is performed in a sulfuric acid or phosphoric acid bath, thereby forming an anodized film on the surface of the aluminum plate. After the anodizing treatment is performed in this manner, a sealing treatment or a hydrophilization treatment is performed as necessary.
[0018]
Thereafter, a photosensitive layer is applied to the aluminum plate.
The photosensitive layer is not particularly limited, and is conventionally used as a photosensitive layer in a photosensitive printing plate material, for example, a negative photosensitive composition composed of a diazo resin and a polymer compound, an o-quinonediazide compound and a novolac resin. A positive photosensitive composition, an addition polymerizable unsaturated monomer, a photopolymerizable composition comprising a photopolymerization initiator and a polymer compound, or a negative photosensitive composition comprising a photocrosslinkable composition containing a cinnamic acid or dimethylmaleimide group. A negative or positive photosensitive composition comprising a composition, a heat mode writing compound or the like as a photosensitive material, or an electrophotographic photosensitive composition or a physical material described in JP-A Nos. 55-161250 and 4-100052. A photosensitive layer using a silver complex diffusion transfer method provided with development nuclei and a silver halide emulsion layer can be used.
[0019]
【Example】
Hereinafter, the present invention will be specifically described based on examples.
Example 1 and Comparative Example 1
First, a coiled aluminum plate (material 1050 according to JIS standard) having a thickness of 0.3 mm and a width of 500 mm is prepared. The coiled aluminum plate is degreased with alkali, then the surface is polished with a nylon brush while applying a water suspension of permiston, and then thoroughly washed with water. Next, the surface of the coiled aluminum plate was etched at 4 g / m 2 with a caustic soda solution, and then washed with running water. Subsequently, it was electropolished in a 1 wt% hydrochloric acid bath at an electric quantity of 200 coulomb / dm 2 and washed with water. Next, it was neutralized and washed in a 20% by weight aqueous nitric acid solution and then anodized in a 10% by weight aqueous sulfuric acid solution to form a 2.0 g / m 2 anodic oxide film. After washing with water, it was immersed in an aqueous solution containing 10% by weight of JlS3 sodium silicate at 70 ° C. for 30 seconds, washed with water and dried.
[0020]
On the aluminum plate thus obtained, a photosensitive solution having the following composition was applied and dried so that the coating weight after drying was 1.8 g / m 2, and a coiled negative photosensitive printing plate (negative type) PS plate) was prepared.
Composition of photosensitive solution 2-hydroxy-3-phenoxypropyl methacrylate / 2-hydroxy ethyl methacrylate / methacrylic acid / methyl methacrylate / acrylonitrile = 30/20/5/20/25 copolymer by weight 3.0 kg
2-methoxy-4-hydroxy-5-benzoyl benzene sulfonate 0.3 kg of condensate of 4-diazodiphenylamine and formaldehyde
Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.1kg
Oxalic acid 0.03kg
Ethylene glycol monomethyl ether 11.0kg
N, N'-dimethylformamide 1.0kg
[0021]
Next, using a slitter device 2 as shown in FIG. 1, the clearance (clearance) between the cutting blades 3b, 3c and 4b, 4c is set to 60 μm, the upper and lower bites (overlap) are set to 1.2 mm, and the width is 398 mm. Slit continuously. After that, it was continuously cut to a length of 560 mm, and both sides of the cut width of 398 mm were polished by rubbing several times back and forth with a No. 600 paper file. At this time, the average value of Ra was 0.57 μm, and Rmax was 10.2 μm.
In addition, it is set as the comparative example 1 that the both sides cut | judged are not grind | polished.
[0022]
Next, the photosensitive printing plate obtained in Example 1 and Comparative Example 1 was subjected to image formation exposure, and then 10 g of potassium silicate, 40 g of phenyl glycol, 5 g of potassium isopropylnaphthalenesulfonate, 2 g of potassium sulfite, and 900 g of water. After developing with a developer consisting of the following, and washing with water, gumming was performed to the cut surface of the surface and end face using an aqueous gum arabic solution of 8 ° Baume. When this part was examined carefully, the lacking part of the gum solution was found in the cut surface of Comparative Example 1.
[0023]
Using these plates, newspaper newspaper manufactured by Nihon Shimbun Ink Co., Ltd. and 0.5% Alky Etch solution manufactured by Toyo Ink Co., Ltd. as dampening water on a newspaper rotary machine manufactured by Tokyo Machine Works Co., Ltd. The printing was performed under the printing conditions in which the amount of ink was larger than normal and the amount of dampening water was smaller. As a result, no stain was observed in the longitudinal peripheral portion of the newspaper printed from Example 1 from the start of printing until the end of printing. On the other hand, linear stains were partially generated from the beginning of printing to the end of printing at the peripheral portion in the longitudinal direction of the newspaper printed from Comparative Example 1.
[0024]
Example 2 and Comparative Example 2
In the same manner as in Example 1, a 960 mm-wide coiled photosensitive printing plate was produced. A slitter device 6 as shown in FIG. 2 was used to set the clearance of each upper blade and lower blade to 30 μm, the overlap to 1.0 mm, and two pieces were continuously cut into a width of 398 mm. Next, the product was cut into a length of 1100 mm to obtain two products. After stacking a total of 500 sheet-like photosensitive printing plates each, both side portions of the cut width of 398 mm were polished with a # 1000 paper file. At this time, the average value of Ra was 0.38 μm, and Rmax was 5.6 μm. In addition, the thing which did not grind | polish both the side parts cut at this time is set as the comparative example 2.
When these plates were used to make a plate in the same manner as in Example 1 and printed, edge stains (frame stains) did not occur in the plate of Example 2, but the plate of Comparative Example 2 had linear stains. Occurred.
[0025]
Example 3 and Comparative Example 3
In the same manner as in Example 1, a 960 mm-wide coiled photosensitive printing plate was produced. Using this slitter device 6 as shown in FIG. 2, the upper and lower blades have a clearance of 30 μm and an overlap of 1.0 mm as in Example 2, and the width is continuously 398 mm. I cut two pieces. Subsequently, both slit sections were polished in contact with a rotating grit buff (grade # 600), and then cut into a length of 1100 mm to obtain two products. At this time, the average value of the roughness Ra of the cut surface was 0.42 μm, and Rmax was 6.2 μm.
In addition, the thing which did not grind | polish both the cross-sections slit at this time is set as Comparative Example 3.
When these plates were exposed, developed, and finished with a finisher gum by an automatic plate making machine FNR402II (Fuji Photo Film Co., Ltd.), the plate of Comparative Example 3 was in contact with the positioning pin due to poor contact with the positioning pin. Several accidents occurred when the platemaking machine stopped due to poor continuity.
Further, the plates of Example 3 and Comparative Example 3 were printed in the same manner as in Example 1. As a result, the plate of Example 3 did not generate stains on the periphery, but the plate of Comparative Example 3 was linear from the start of printing. Dirt occurred.
[0026]
【The invention's effect】
From the above results, in the printing plate produced from the photosensitive printing plate of the present invention, even when the printing conditions are severe, the edge stain (frame stain) does not occur in the printing peripheral portion, and the continuity failure also in the plate making machine. No accidents occur.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view when a photosensitive planographic printing plate is cut in a horizontal state using a slitter device.
FIG. 2 is a cross-sectional view when a photosensitive lithographic printing plate is cut using a slitter device using four pairs of upper and lower cutting blades.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive lithographic printing plate 1a Aluminum support body 2 Slitter apparatus 3 Cutting machine 3a Rotating shaft 3b Upper cutting blade (upper blade)
3c Upper cutting blade (upper blade)
4 Cutting machine 4a Rotating shaft 4b Lower cutting blade (lower blade)
4c Lower cutting blade (lower blade)
5 Slitter device 11 Cross section (end face)
A Photosensitive layer D Product part E Unnecessary part

Claims (3)

  A method for producing a photosensitive lithographic printing plate, comprising: cutting a photosensitive lithographic printing plate into a predetermined size with a slitter having at least one pair of cutting blades; Graining been cut surfaces, the manufacturing method of the photosensitive lithographic printing plate according to claim 1, which is similar roughness and the photosensitive lithographic printing plate of the support surface.   A method for producing a photosensitive lithographic printing plate, comprising: cutting a photosensitive lithographic printing plate into a predetermined size with a slitter having at least one pair of cutting blades;

Images