JPH1191072A - Lithographic press and lithographic printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance print dimensions and accuracy while preventing deterioration in workability by forming a plurality of microprotrusions on the surface of a plate cylinder while specifying the height and the surface average number thereof. SOLUTION: A plurality of microprotrusions are formed, while being distributed, on the surrounding surface of a plate cylinder. More specifically, microprotrusions having height of 40 μm or above are formed at a rate of 20 pieces/cm<2> in surface average and microprotrusions having height of 3 μm or above are formed at a rate of 25 pieces/cm<2> . Consequently, distortion suppressing force of a lithographic printing plate acts effectively at the time of printing. The microprotrusion has rod-like, pyramidal or acicular shape. The microprotrusions are formed on the plate surface by (1) direct blasting, (2) pressing with a roll having microprotrusions, (3) spraying, (4) electrical discharge machining, (5) laser etching, (6) electron beam abrasion, (7) direct coating with dispersion liquid of microparicles, or the like. The microprotrusions are preferably made of an inorganic material in view point of mechanical strength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithographic printing press and a lithographic printing method using the same.

[0002]

2. Description of the Related Art In a lithographic printing press, a printing plate is generally wound around a plate cylinder, mechanically fixed, and printing is performed in this state.

However, a lithographic printing plate having a substrate made of a material other than metal (for example, plastic film, paper, etc.) that is easy to handle has a problem in dimensional stability. The friction causes a problem in that the plate is partially distorted, thereby impairing the printing dimensions and printing accuracy.

[0004] Therefore, in the case of a plate using the above-mentioned base material, it is conventionally limited to a simple printing of a small number of sheets which does not require much registration accuracy of a printed matter.
It was not used as it is for multicolor and sophisticated high-end printing or full-scale printing using a large printing machine.

In order to solve such a problem, Japanese Utility Model Application Laid-Open No.
Japanese Patent Application Laid-Open No. 8-1046 proposes a method of directly adhering a plate material to a plate cylinder or an underplate for tailoring using, for example, an acrylic or rubber double-sided pressure-sensitive adhesive sheet or a spray adhesive.

However, in such a method, since the printing plate is firmly adhered to the plate cylinder, fine adjustment of the position of the printing plate on the plate cylinder is not possible, and workability such as plate discharging after printing is extremely low. There is a new problem of deterioration.

Further, Japanese Patent Publication No. 7-425 proposes a method of improving the printing accuracy and the like by providing a specific silicone rubber film on a plate cylinder of a printing press.

However, in this method, since the silicone rubber film does not peel off from the printing press, it is difficult to remove it easily, for example, as in the case of a conventional underlaying material for a printing plate. If you use
It is necessary to replace the tailoring underlay material according to the thickness of the plate, but there is a problem that the workability of the replacement is extremely deteriorated.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the printing plate from being partially distorted during printing, thereby impairing the printing dimensions and printing accuracy, and also to avoid the problems of the conventional printing method. It is an object of the present invention to provide a lithographic printing machine and a lithographic printing method capable of eliminating the deterioration of workability at the time.

[0010]

This and other objects are achieved by the present invention which is defined below as (1) or (2). In lithographic printing press having (1) plate cylinder, 20 / cm ² or less in the average surface that plate cylinder of height 40μm greater, more than height 3μm is in average surface 25 / cm ² or more A lithographic printing press having a surface on which a plurality of microprojections are formed. (2) A lithographic printing method in which a lithographic printing plate is wound around a plate cylinder for lithographic printing described in (1) and printing is performed.

[0011]

According to the present invention, a lithographic printing plate cylinder having a plurality of microprojections formed on its surface is used to oppose the force applied to the lithographic printing plate during printing due to frictional resistance with the lithographic printing plate. Strain (elongation) is suppressed. In addition, since the plate cylinder does not suppress the distortion of the planographic printing plate by the adhesive force as in the related art, it is easy to remove the printing plate material.

Therefore, the planographic printing plate cylinder of the present invention reliably prevents distortion of the printing plate without sacrificing workability.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a specific configuration of the present invention will be described in detail.

[0014] A printing machine which can be used in the present invention comprises an ink supply device for forming an ink film having a constant thickness on at least the surface of an inking roller, an image portion for receiving ink and a non-image portion for which ink is not attached. A printing cylinder comprising a printing cylinder having a printing plate mounted thereon by gripping and fixing the printing plate head of the printing plate, and pulling and pressing the printing plate as needed, and a printing cylinder for pressing a printing material onto the printing cylinder to perform printing. Any printing press may be used, for example, between the plate cylinder and the impression cylinder of the printing press,
An offset printing press or the like to which a blanket cylinder for transferring an image by pressing against the plate cylinder and pressing the image against a printing material to print the image can be used.

Next, a plate cylinder for preventing distortion (elongation) of a lithographic printing plate according to the present invention will be described.

The plate cylinder of the present invention has a plurality of fine projections distributed on the surrounding surface. The height of this microprojection is
1 to 50 μm is preferred. Those having a height of more than 40 μm preferably have a surface average of 20 particles / cm ² or less, particularly preferably zero. 25 pieces having a height of 3 μm or more /
cm ² or more, particularly preferably 400 pieces / cm ² or more. When the distribution of the fine projections is within the above range, the distortion suppressing force of the lithographic printing plate during printing effectively acts.
It should be noted that there is no particular upper limit on the distribution number of the fine protrusions having a height of 3 μm or more.

The shape of the microprojections is not particularly required, but is usually a rod, a pyramid, a needle, or the like.

As a method of forming the fine projections, the fine projections are directly formed on the plate surface.
(1) Blasting treatment to form minute projections, (2) Rolling (pressing) with rolls on which minute projections are formed to form minute projections, (3) thermal spraying, (4) electric discharge machining, (5) laser etching Hour, (6)
Ablation by electron beam, (7) Photoresist coating → exposure of microprojection pattern → removal of developed resist → formation of microprojections by etching, (8) Dispersion of microparticles dispersed in binder is directly applied to plate surface and dried And forming a sheet having fine projections on the surface of the metal plate.

As the latter method, (9) a method in which a dispersion liquid in which fine particles are dispersed in a binder is prepared, and this is applied and dried on the surface of a sheet-like substrate; Is pressed into the binder with mechanical pressure. Here, the above (8) will be described as an example.

The average particle size of the fine particles used is 2 to 5
It is preferably about 0 μm.

The fine particles may be either an organic material or an inorganic material, but are preferably inorganic materials since the mechanical properties of the small projections are required.
This inorganic material includes diamond, emery, spinel, garnet, fluorite (flint), alumina (melt), silicon carbide, boron carbide, other carbides, clays, talc, microcrystalline silicic acid, iron oxide (III), chromium (III) oxide, alumina (calcined product), silica stone, rocks and synthetic composite crystals to which fine particles of other hard minerals are bonded.

Such a material is crushed into fine particles so as to meet the above conditions.

As the binder, silicone resin, polystyrene, polyacrylic acid or polymethacrylic acid ester, polyvinyl acetate, polyvinyl chloride, polyvinyl butyral and derivatives thereof are used.

In this binder, the fine particles are
It is preferable to contain about 80 wt%.

As the material of the surface portion of the plate cylinder itself, stainless steel plated with chromium or the like is generally used, but all materials used for the plate cylinder of a printing press are applied. Since the structure and material of the plate cylinder itself may be the same as those of the conventional one, further description is omitted.

The coating of the fine particle-dispersed coating liquid on the plate cylinder surface may be any method that can apply the coating liquid uniformly and disperse the fine particles as uniformly as possible. For example, a roll coater, a spray gun, a bar coater, or the like may be used. Can be The film thickness of only the binder obtained in this manner is 0.1 μm.
m to 50 μm, preferably 0.3 μm to 10 μm. Then, some of the fine particles protrude from the surface of the binder layer to form fine protrusions.

The method of mounting the printing plate on the plate cylinder of the present invention is exactly the same as the usual method, for example, it is only necessary to fix the printing plate with a crook vise. In this way, by bringing the microprojection forming surface of the plate cylinder and the printing plate back surface into close contact with each other, it is possible to suppress distortion during printing of the printing plate, for example, distortion of the plate caused by friction between the blanket and the plate during printing, As a result, the printing size and accuracy can be maintained.

The plate cylinder of the present invention can withstand repeated use. However, depending on the conditions, dust and moist water components adhered to the back surface of the plate material adhere to the surface on which the fine projections are formed, and the dimensional stability of the plate material is reduced. May lower. In such a case, the performance can be restored by washing with water or an organic solvent or the like, and it can be used repeatedly.

The repetition resistance is determined by measuring the area of contact with the adhesive layer of a cloth (made of cotton) in which the surface on which the projections are formed is impregnated with water or an ink cleaning liquid Daiclean R (released by Dainippon Ink and Chemicals, Inc.). fixed to a dedicated jig such that × 0.5 mm ^2, in parallel to reciprocate the contact portion in the load 0.5kg by the surface property measuring instrument HEIDON-14 type, repeated when the adhesive layer is and lose solubility or membrane The number of reciprocations was measured. If the number of reciprocations is 50 or more, the repetition resistance is good.

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

Example 1 On the surface of a chrome-plated stainless steel plate cylinder, an acrylic resin (Fuji Photo Film Co., Ltd.) was used as a binder for the following five kinds of inorganic particles and the particles shown in Table 1. Excel Auto Homogenizer (manufactured by Nippon Seiki Co., Ltd .; Tg = 37 ° C., 40% toluene solution) in toluene.
After dispersing at 12,000 rpm for 15 minutes, the mixture was applied and dried with a wire bar to a dry coating amount of 10 g / m ² to obtain a sample of a plate cylinder. The coated surface of a series of these samples was measured using a three-dimensional surface roughness meter manufactured by Kosaka Laboratory Co .;
The height of the protrusions and the density of the protrusions were measured using LSE-3F1, PU-DJ2U and MODEL SPA-11 analyzer.

The following five types of inorganic particles were used: FO # 500, FO # 1200, FO # 3000, A #
320, A # 240 (both manufactured by Fujimi Incorporated)

Table 2 shows the composition of each of the above-mentioned inorganic particles and the particle diameter at a cumulative height of 94%.

Table 1 shows the formulations of the coating materials prepared and the densities according to the height of the protrusions on the completed surface.

[0035]

[Table 1]

[0036]

[Table 2]

The printing plate elongation during printing was measured under standard printing conditions using an Oliver 52 printing machine manufactured by Sakurai Machinery Co., Ltd. The printing plate is ELP-5 manufactured by Fuji Photo Film Co., Ltd.
An ELP-2X master made with an 80 plate making machine was used. The ink and fountain solution used were standard materials for this system.

After printing 2000 sheets, the elongation of the plate from the start of printing was actually measured on the printed coated paper. In the measurement, the interval between two ruled lines drawn at intervals of 30 cm in the rotation direction of the plate cylinder as an image on the printing plate was actually measured on the printed matter after the start and after 2,000 sheets, and the difference was defined as the plate elongation.

The 2000th printed matter has large projections due to inorganic particles on the surface of the plate cylinder, and if the number of large projections is large, the printed image is lost, and the printed matter cannot be used in terms of quality. From this, the degree of missing of the image on the printed matter was visually evaluated. Table 3 shows the results.

[0040]

[Table 3]

As is apparent from the above description, when the number of projections on the surface of the plate cylinder is not more than 25 μm / cm ² , the effect of suppressing the distortion (elongation) of the plate material is not sufficient. On the other hand, when the number of particles having a size of 40 μm or more is 20 pieces / cm ² or more, image missing is conspicuous. Therefore, it was confirmed that when the density of the projections having the predetermined height was within the range of the present invention, distortion (elongation) of the plate material could be satisfactorily prevented while maintaining good images.

The printing operation values were good in all samples.

Example 2 A plate cylinder of an automatic printing machine AM1280 manufactured by AM Co., Ltd. was used as much as possible by using a polishing cloth roll [silicon carbide abrasive GC, particle size type P1000 (particle diameter of a cumulative height of 94% point of 7.0 μm)]. After being polished uniformly, thoroughly washed with water and dried, the surface roughness was measured in the same manner as in Example 1. Average surface roughness R after polishing
a is 27 [mu] m, height 40μm than the average 7 / cm ^2, more height 3μm was averaged 8910 pieces / cm ^2. Before polishing, protrusions of 3 μm or more were due to scratches due to impact, and had an average of 1.5 protrusions / cm ² . Elongation of the plate before and after polishing was measured using this plate cylinder in the same manner as in Example 1. The printing plate is ELP-330RX manufactured by Fuji Photo Film Co., Ltd.
An ELP-2X master made by a plate making machine was used. The ink and fountain solution used were standard materials for this system. 2
After printing 000 sheets, the elongation of the plate from the start of printing was actually measured on the coated coated paper. The measurement was performed on the printing plate, starting with the interval between two ruled lines drawn at intervals of 30 cm in the direction of rotation of the plate cylinder as an image on the printing plate, and actually measuring 2,000 sheets after printing.
The difference was defined as plate elongation. Before the polishing, the plate elongation was 1.4 mm, whereas after the polishing, it was 0.2 mm. No deterioration was observed in the printed image during printing, and it was confirmed that elongation of the printing plate could be favorably prevented.

[0044]

As described above, according to the present invention, the dimensional stability and printing workability of a plate material in a lithographic printing press can be improved satisfactorily while maintaining a good printed image.

Claims (2)

[Claims] 1. A lithographic printing press having a plate cylinder, wherein the plate cylinder having a height of more than 40 μm has an average surface area of not more than 20 / cm ² , and the plate cylinder having a height of not less than 3 μm has an average surface area of 25 / cm. ^Two
A lithographic printing press having a surface on which a plurality of minute projections are formed. 2. A lithographic printing method in which a lithographic printing plate is wound around a plate cylinder for lithographic printing according to claim 1 for printing.