JP3010403B2 - Lithographic printing plate support and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate support using an aluminum plate and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, an aluminum plate has been widely used as a support for a lithographic printing plate. The lithographic printing plate formed by using the aluminum plate has good adhesion to a photosensitive layer provided thereon. The surface of the aluminum plate is usually roughened for the purpose of improving the water retention of the non-image area of the plate (the area that receives the fountain solution used during printing and repels the oil-based ink). . This roughening treatment is called graining, and is indispensable for a lithographic printing plate support. This graining can be performed by mechanical graining methods such as ball graining, wire graining, brush graining, electrolytic graining method of electrochemically etching in acid or neutral aqueous solution, or special aluminum There is known a chemical surface roughening method of chemically etching with an acid or an alkali using an alloy.

[0003] However, these methods have the following problems. That is, when performing mechanical graining, it is necessary to have skill in adjusting the machine and the abrasive, and it is necessary to remove the abrasive and aluminum debris that have cut into the surface of the roughened aluminum plate. The problem with the chemical graining method is that it is necessary to finely adjust the liquid temperature, electrolysis conditions, liquid composition, etc. to match a narrow range.In the case of the electrochemical graining method, the power consumption is increased in addition to the chemical graining method. Is large, and the ratio to the cost is considerably large. As a method capable of solving such a defect, a method for producing a grain by transferring the rough surface pattern of a roller by rolling and transferring an aluminum plate with a roughened roller is disclosed in Japanese Patent Application Laid-Open No. Sho 55-74898, Japanese Patent Publication No. Sho 55-74898. No. 4,030,358 and JP-A-61-162351. The method of roughening the roller described in these known materials uses sand blast, grid injection, electric discharge machining, and the like.

[0004]

However, the method of rolling-transferring the roughened roller to an aluminum plate is one of the important factors for determining the performance of a lithographic printing plate support. Has the drawback that the range in which the grain can be controlled is very narrow or difficult. This is because sandblasting and grid injection randomly apply fine particles to the roller surface, so that the vertices of the irregularities formed on the roller surface are not uniform in height. For this reason, in order to uniformly transfer the grain on the surface of the transferred object, for example, the aluminum alloy plate, it is necessary to increase the reduction amount or the reduction ratio. As a result, the already formed concave portions are crushed and overlapped. It is difficult to control the grain because it has a grain shape and a shape different from the irregularities formed on the surface of the transfer roller. For example, 4-30
No. 358 describes that concave portions formed by pressing partially overlap each other to form a wavy pattern. Further, the performance of the lithographic printing plate also has a drawback that a partially anchored and corrugated concave portion cannot provide a sufficient anchoring effect between the photosensitive layer and the support, resulting in poor printing performance.

An object of the present invention is to solve the above-mentioned problems, and to provide a good lithographic printing plate support in which the depth of unevenness is uniform and the average diameter of concave portions is uniform, and a method for producing the same.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a lithographic printing plate support using an aluminum plate, wherein the surface of the aluminum plate is uniformly roughened by pressing a transfer roller whose surface has been roughened by a laser. A support for a lithographic printing plate characterized by having a roughened grain, or a transfer roller roughened by the laser having a maximum height of 5 to 3;
0 μm, the average diameter of the protrusions on the transfer roller surface is 2 to 50 μm
This is achieved by a method for producing a lithographic printing plate support, characterized by graining using a transfer roller of m.

In the present invention, the aluminum plate used includes pure aluminum and aluminum alloy.
Various materials can be used as the aluminum alloy. For example, an alloy of aluminum, such as an alloy of silicon, copper, manganese, magnesium, chromium, zinc, lead, nickel, or bismuth, is used. There are various types of aluminum alloys.
In US Pat. No. 6,635, the Fe and Si components are limited, and an intermetallic compound is specified. In addition, Japanese Patent Publication No. 55-28874
In this publication, the cold rolling ratio and the intermediate annealing are performed, and the voltage application method for electrolytic surface roughening is limited. Tokiko Sho 62-4130
4, Tokiko 1-46577, Tokiko-1-46578,
Tokiko 1-47545, Tokiko 1-35910, Tokiko 63-60823, Tokiko 63-60824, Tokiko 4
-13417, 4-19290, 4-19
No. 291, Tokuhei 4-19293, Tokiko 62-5054
0, JP-A-61-272357, JP-A-62-7406
0, JP-A-61-201747 and JP-A-73-1432.
34, JP-A-63-143235, JP-A-63-255
338, JP-A-1-283350, EP272
528, U.S. Patent Nos. 4,902,353 and 4,818,300;
EP394816, U.S. Pat. No. 5,019,188, West German Patent 3,232,810, U.S. Pat.
39959, U.S. Pat. No. 4,822,715, West German Patent 3
507402, U.S. Pat. No. 4,715,903, West German Patent 3507402, EP 289844, U.S. Pat.
722, 495,004, West German Patent 371405
9, US Patents 4,686,083, 4,861,396, EP
It includes not only the aluminum alloys described in the specifications of the 158941 specification, but also all general ones. As a method for manufacturing a sheet material, a method using continuous casting as well as a method using hot rolling has been recently applied for. For example,
In the specification of East German Patent 252799, a plate material made by a twin roll method is introduced. EP22373
7, US Pat. Nos. 4,802,935 and 4,800,950,
The application has been filed with a limited amount of alloy components. EP41
5238 proposes continuous casting, continuous casting + hot rolling.

In the present invention, such an aluminum plate can be subjected to various surface treatments, transfer and the like to obtain a printing original plate having uniform unevenness, and a photosensitive layer such as a diazo compound is provided thereon. And an excellent photosensitive lithographic printing plate can be obtained. In any case, it is necessary to select an appropriate material.

Next, the processing conditions for these aluminum plates will be described. Prior to the present invention (by transfer), pretreatment may be performed to remove the rolling oil on the aluminum surface and to expose a clean aluminum surface. In the former case, a solvent such as trichlene or a surfactant is used. For the latter, a method using an alkali etching agent such as sodium hydroxide or potassium hydroxide is widely used. In Japanese Patent Application Laid-Open No. 2-026793,
It describes a degreasing treatment. For example, solvent degreasing methods include methods using petroleum solvents such as gasoline, kerosene, benzene, solvent naphtha, and normal hexane, and chlorine-based methods such as tolchlorethylene, methylene chloride, perchlorethylene, and 1-1-1 trichloroethane. There is a method using a solvent. Examples of the alkaline degreasing method include a method using a soda salt such as sodium hydroxide, sodium carbonate, sodium bicarbonate, and sodium sulfate, and a silicic acid such as sodium orthosilicate, sodium metasilicate, sodium 2 silicate, and sodium silicate 3. A method using an aqueous solution of a salt, a method using an aqueous solution of a phosphate such as sodium phosphate monobasic, sodium phosphate tribasic, sodium phosphate dibasic, sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate, and the like can be given. When using the alkaline degreasing method, depending on the processing time and processing temperature,
Since there is a possibility that the aluminum surface may be dissolved, it is necessary to prevent the dissolution phenomenon from being involved in the degreasing treatment. As the degreasing treatment with a surfactant, an aqueous solution of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant is used, and various commercially available products can be used. As the degreasing method, the dipping method,
A spraying method, a method in which a liquid is immersed in a cloth or the like, and rubbed can be used. Ultrasonic waves may be used for the immersion or blow-dipping method.

The roughening of the transfer roller by laser is used for an anilox roller used for flexographic printing. For this reason, fine concave portions exist on the transfer roller surface. Therefore, even if the transfer is performed using this roller, only the projections are formed on the surface of the object to be transferred (for example, an aluminum plate), which is not suitable for a lithographic printing plate support. Therefore, in the present invention, as shown in FIG. 1, a convex portion 12 is formed on the roller surface by synthesizing a swelling of a dissolved component generated when the laser is irradiated, thereby forming a concave portion on the transfer object. The laser used is preferably a CO ₂ laser, and may be a YAG laser or an excimer laser. In FIG. 2, 21 is a vertical groove, 22 is a horizontal groove, and the vertical and horizontal grooves are formed by laser irradiation. The vertical grooves and the horizontal grooves are arranged at right angles or at an angle. The non-transferred surface is roughened by the mutually independent convex portions 23 cut by the vertical and horizontal grooves. A YAG laser using the fourth harmonic has a similar range. A YAG laser (wavelength 1.06 μm) is used for a groove width of 10 μm or more. Since the CO ₂ laser has a long wavelength (10.63 μm), it is used for a groove width of about 40 μm or more.

[0011] Transfer is performed on an object to be transferred using such a roughening roller (hereinafter, referred to as a transfer roller). Roller material is SUS304, SUS316, SCM steel, SS
It is desirable to use a metal such as 41 from the viewpoint of strength, cost, chemical resistance and the like. When these metals are directly irradiated with laser, the grooves formed by the first irradiation of the laser are crushed by the molten metal component by the second irradiation of the laser. For this reason, an independent convex portion cannot be obtained clearly, and it is difficult to form a precise convex portion by laser.
This is because the energy density of the laser is high while the melting point of the metal is generally low. In the present invention, in order to prevent this, a ceramic having a melting point higher than that of the metal is formed on the surface layer of the metal roll by a thermal spraying method, and by irradiating a laser to this layer, an independent convex portion is accurately obtained. is there. In order to improve the bond between the metal surface and the ceramic, Ni, Ni is placed between the metal surface and the ceramic layer.
A coupling layer made of Al or the like may be provided.

The thickness of the sprayed film is preferably from 0.1 mm to 0.6 mm. The thermal spraying method is preferably plasma spraying, and the ceramic powder used for thermal spraying is preferably finer. Alternatively, the ceramic may be sintered, rolled, polished, and then irradiated with a laser. Ceramics used include white alumina, gray alumina, a mixture of white alumina and titanium dioxide, a mixture of gray alumina and titanium dioxide, chromium oxide, a mixture of chromium oxide and titanium dioxide, a mixture of chromium oxide and silica, zirconia, and titanium dioxide. , Silicon nitride, nitrides such as aluminum nitride, and carbides. The amount of reduction in the transfer is preferably in an extremely low reduction region of 5 μm to 100 μm.
By performing the transfer in such an extremely low pressure drop region, it is possible to prevent the flatness of the transferred object from being deteriorated. The transfer can be performed not only in one pass but also in a plurality of passes.
It is desirable that the maximum height of the surface of the transfer roller is 5 to 30 μm, and the average diameter of the convex portion of the roller is 2 to 50 μm.

[0013]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by the embodiments without departing from the gist thereof. (Example-1) The surface of an SCM steel roll was roughened by sand blasting, a bonding layer was formed by Ni and Al, and then a mixture of chromium oxide and silica was sprayed on the SU by plasma spraying.
A 0.2 mm thick thermal spray is applied to the S cola. After the thermal spraying, the maximum roughness (Rmax) is about 50 μm on a mirror-finished roller surface with a thickness of 0.2 μm, and on a boundary-finished roll surface with a CO ₂ laser processing machine with a rated output of 400 W.
m concave portions are formed, and convex portions are formed by simultaneously generated dissolved components. By this method, a projection roller was formed by forming 200 lines per 1 mm. In an apparatus in which this is used as an upper roller and a boundary finishing roller made of SCM steel is used as a lower roller, an aluminum plate (JIS1050 material) having a thickness of 0.24 mm is passed between the upper and lower rollers. At this time, the gap between the upper and lower rollers is 10 μm larger than the thickness of the aluminum plate.
m. The aluminum plate is transferred not only once but also five times. The center line average roughness Ra of the aluminum plate after the transfer was 0.85 μm.

This aluminum plate was immersed in an aqueous solution containing 5% of caustic soda at 60 ° C. to remove 1 g / g of the surface of the aluminum plate.
After polishing with m ^2, the aluminum plate was washed with water, further immersed in an aqueous solution containing 25% of sulfuric acid at 60 ° C. to remove hydroxide on the surface of the aluminum plate, and washed with water. The aluminum plate was further placed in an aqueous solution containing 10% sulfuric acid at 33 ° C. with aluminum as an anode, and a current density of 2 A / d was obtained using a continuous DC power supply.
The resultant was subjected to anodizing treatment with m ² , washed with water, and dried. At this time, the center line average roughness Ra was 0.55 μm. A photosensitive solution was applied to the support thus obtained and dried to provide a photosensitive layer. The coating weight after application of the photosensitive layer is 2.0 g / m
^{Was 2} . The lithographic printing plate thus obtained was a printing plate having good performance.

Example 2 A negative photosensitive solution was applied to a support obtained in the same manner as in Example 1 and dried to form a photosensitive layer. The printing plate thus obtained was a printing plate having good performance.

(Embodiment 3) After roughening the surface of a SUS roller by sandblasting, forming a bonding layer of Ni and Al, a mixture of chromium oxide and silica was plasma-sprayed on the SUS roller to a thickness of 0%. Perform 2 mm thermal spraying. After the thermal spraying, a mirror finish with a maximum roughness (Rmax) of 0.2 μm is performed, and the vertical groove width is 10 μm, the horizontal groove width is 10 μm, and the groove interval is 30 μm by an excimer laser processing apparatus having a rated output of 50 W.
Then, a transfer roller having a plurality of 15 μm square independent protrusions was manufactured. The transfer roller thus obtained does not scatter the molten metal particles, has a smooth convex surface, and has a variation in height of irregularities of ± 0.5.
The rollers had a size of not more than μm.

[0017]

A lithographic printing plate support having a grain transferred by a roller roughened by a laser has a surface suitable for a printing plate.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views of unevenness on a surface of a transfer roller used in the present invention, which is synthesized by a molten component by a laser, FIG. 1A is a plan view, and FIG.

FIG. 2 is a diagram showing the relationship between grooves and protrusions of a transfer roller made by a laser used in the present invention.

FIG. 3 is a replica photograph (magnification × 1000) of a roller surface roughened by a CO ₂ laser obtained in Example-1.

FIG. 4 is a photograph (magnification × 34) of a surface of an aluminum plate transferred by a roughened roller obtained in Example-1.
0)

FIG. 5 is a scanning electron micrograph (magnification: × 1000) of the surface of an aluminum plate subjected to chemical and electrochemical surface treatment after transfer obtained in Example-1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Convex part 20 Transfer roller 21 Vertical groove 22 Horizontal groove 23 Convex part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-74898 (JP, A) JP-A-60-36194 (JP, A) JP-A-61-162351 (JP, A) 179796 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41N 3/04

Claims (2)

(57) [Claims] 1. A lithographic printing plate support using an aluminum plate, wherein the surface of the aluminum plate has a grain which is uniformly roughened by pressing a transfer roller roughened by a laser. Lithographic printing plate support 2. The surface roughened by a laser having a maximum height of 5
A method for producing a support for a lithographic printing plate, comprising graining using a transfer roller having a thickness of from 30 to 30 μm and an average diameter of the projections of from 2 to 50 μm.