JP2001228601A - Method for producing photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the peeling of a mat and the formation of powder by keeping the sphere diameter of mist and the surface temperature of a photosensitive planographic printing plate in an appropriate relation. SOLUTION: When an aqueous fluid is sprayed as mist on each photosensitive layer of a photosensitive planographic printing plate 10, the sphere diameter of mist L in spraying is adjusted to 16-40 μm, the mist is electrostatically stuck and the temperature of the printing plate 10 is regulated to the range of 7-37 deg.C. By the control of both the sphere diameter of the mist L and the temperature of the printing plate 10, the peeling of a mat (m) from the photosensitive layer is prevented and the surface of printer glass is not contaminated. When the photosensitive planographic printing plate and a photographic original plate are overlapped and vacuum-attracted, powder does not clog a vacuum pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a photosensitive lithographic printing plate for forming a mat on a photosensitive layer of the photosensitive lithographic printing plate.

[0002]

2. Description of the Related Art In an image exposing step for forming an image on a photosensitive lithographic printing plate, image blurring occurs unless the photosensitive lithographic printing plate and the photographic original plate are closely overlapped with each other without gaps. Therefore, in general, using a vacuum frame, a photosensitive lithographic printing plate and a photolithographic plate are superimposed between a glass plate and a rubber sheet of the vacuum frame, and a vacuum is applied between the glass plate and the rubber sheet to expose the photosensitive plate. The lithographic printing plate and the photographic original plate are in close contact.

Then, a photosensitive lithographic printing plate 30 shown in FIG.
In order to improve the adhesion between the lithographic printing plate 30 and the lithographic printing plate 32, a fine droplet is spray-coated on the photosensitive layer of the photosensitive lithographic printing plate 30 to form a mat layer M1 with an infinite number of substantially trapezoidal mats m1. Air is easily released from between the lithographic printing plate 30 and the photographic original plate 32.

[0004] As a matting method for improving the adhesion between the mat layer and the photosensitive layer, Japanese Patent Publication No. 61-4899 has been proposed.
No. 4 is mentioned. This technology raises the surface temperature of a photosensitive lithographic printing plate during transport to 65 ° C in a temperature control chamber, wets the photosensitive layer with a wetting device, and then uses an electric field to apply water-soluble The fine droplets are electrostatically attached to the surface of the photosensitive layer.

Incidentally, as the line speed increases, the surface temperature of the photosensitive lithographic printing plate in the temperature control chamber tends to increase. However, when the surface temperature of the photosensitive lithographic printing plate is high and the diameter of the mat (the diameter of the mat attached to the photosensitive layer) is small, the mat is easily peeled off. This tendency also has a problem that, in the electrostatic coating method, the larger the diameter of the liquid jetted from the spray head, the larger the amount of shrinkage on the surface of the photosensitive lithographic printing plate.

[0006] However, in the prior art, a preferable range is defined for the shape and height of the mat attached thereto.
It is not disclosed how the ball diameter of the ejected droplets and the surface temperature of the photosensitive lithographic printing plate affect the peeling of the mat.

[0007] On the other hand, when the mat is peeled off, it becomes powder and stains the surface of the printer glass, and when the photosensitive lithographic printing plate and the photographic original plate are superimposed and vacuum-adsorbed, the powder may clog the vacuum pump.

[0008]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention prevents the mat from peeling off by keeping the spherical diameter of the droplet and the surface temperature of the photosensitive lithographic printing plate in an appropriate relationship. The problem is to prevent the occurrence of

[0009]

According to the first aspect of the present invention, when the aqueous liquid is jetted as fine droplets onto the photosensitive layer of the photosensitive lithographic printing plate, the sphere diameter of the droplets at the time of the ejection is 16 μm. More than 40μ or less, electrostatically adhered, and further temperature-controlled, the temperature of the photosensitive lithographic printing plate at the time of proper liquid jetting was 7 ° C.
To 37 ° C.

As described above, by controlling both the diameter of the ejected droplet and the temperature of the photosensitive lithographic printing plate, the mat does not peel off from the photosensitive layer. Thereby, the surface of the printer glass is not stained, and the powder does not clog the vacuum pump when the photosensitive lithographic printing plate and the photographic original plate are superimposed and vacuum-adsorbed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for producing a photosensitive lithographic printing plate according to the present embodiment will be described with reference to the schematic diagram of FIG.

A photosensitive lithographic printing plate 10 coated with a photosensitive liquid
Is introduced into the temperature control chamber 12. This temperature control room 12
Then, when cool air is blown onto the photosensitive lithographic printing plate 10 and reaches the electrostatic coating device 14 described later, the photosensitive lithographic printing plate 1
The surface temperature of 0 is adjusted to be in the range of 7 ° C to 37 ° C. After that, it is sent to the wetting device 18 by the pass roll 16.

The wetting device 18 sprays and wets the surface of the photosensitive lithographic printing plate 10 or both surfaces with a steam spray tube. The wet photosensitive lithographic printing plate 10 is sent to the electrostatic coating device 14.

[0014] As shown in FIG.
The aqueous liquid in which the resin is dissolved or dispersed is ejected as fine droplets L and adheres to the surface. Here, the average sphere diameter of the droplet L at the time of ejection is 16 μm to 40 μm, and the flying distance is about 600 mm in the case of a negative photosensitive lithographic printing plate and about 750 mm in the case of a positive photosensitive lithographic printing plate. It has been.

As described above, by adhering the droplet L having an average sphere diameter of 16 μm to 40 μm to the photosensitive layer of the photosensitive lithographic printing plate 10 at a relatively low temperature set at a temperature in the range of 7 ° C. to 37 ° C.
It is possible to form a mat which does not undergo rapid temperature shrinkage as in the case of high temperature and is hardly peeled off. Therefore, no powder is generated due to peeling of the mat, and the surface of the printer glass is soiled.In addition, when the photosensitive lithographic printing plate and the photographic original plate are superimposed and vacuum-adsorbed, the vacuum pump may be clogged with the powder. Absent.

Further, there is no problem that the photosensitive layer to which the mat is adhered is peeled off at the same time to cause a film breakage in a fine image portion. Further, when a large number of photosensitive lithographic printing plates are stacked, they are sandwiched between them. It does not cause slippage with the paper and does not deteriorate the transportability of the photosensitive lithographic printing plate as a bundle.

The flying distance is changed between the positive case and the negative case by adjusting the amount of water in the liquid droplets L that evaporates according to the ambient atmospheric temperature during the flight, so that the amount of the liquid at the time of adhering is changed. This is for changing the sphere diameter of the droplet.

Therefore, in the case of the positive, the flying distance is 750
mm, and the moisture becomes extra, so the concentration becomes higher,
As shown in FIG. 2A, a so-called standing mat ma is formed. On the other hand, in the case of a negative, the flying distance is 6
Since it is as short as 00 mm, moisture does not escape much, the concentration is low, and as shown in FIG. 2B, since it adheres in a shading state, a so-called lying mat mb is formed.

As described above, the shape of the mat is changed depending on whether it is positive or negative, in consideration of the ink adhesion at the time of printing, and in response to the demands of the market.

On the other hand, the photosensitive lithographic printing plate 10 on which the mat m is formed is again wet by being sprayed with steam by the wetting device 20 arranged on the downstream side. Then, after wetting, it is sent to the drying chamber 22 and dried in a heated and low-humidity indoor atmosphere, or dried by blowing hot air, and discharged to the outside by the pass roll 24 as a product.

Next, a specific experimental example using the method for producing a photosensitive lithographic printing plate according to the present embodiment will be described.

The web of the aluminum plate used as the support of the photosensitive lithographic printing plate 10 was 0.24 mm thick, was grained on both sides, and was thoroughly washed with water. To this web, 2 parts by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester of polyhydrocyphenyl obtained by polycondensation of acetone and pyrogallol / parts by weight of novolak-type phenol formaldehyde resin was added to 20 parts by weight of 2-methoxyethyl. A photosensitive solution was prepared by dissolving in acetate and 20 parts by weight of methyl ethyl ketone, and the web was coated and dried one side at a time.

Next, steam was applied to the photosensitive layer of the photosensitive lithographic printing plate 10 for about 2.5 seconds, and then an aqueous liquid was applied by a rotary atomizing electrostatic coating method. This aqueous liquid was methyl methacrylate-ethyl acrylate-sodium acrylate (weight ratio 68: 2).
(0:12 (charge ratio)) The aqueous solution of the copolymer was adjusted to a solid concentration of 10%.

The aqueous liquid having such a concentration is discharged into a mist by the centrifugal force of the cup-shaped spray head having a bell rotation speed of 17000 rpm and the electrostatic action of the cup-shaped spray head applied to the bell high voltage: -80 kv. Into fine droplets that are atomized and charged by the action of a high electric field formed between the cup-shaped spray head and the photosensitive lithographic printing plate.
It is set to 0 μm to fly onto the surface of the photosensitive layer and electrostatically adhere.

Approximately 3 seconds after that, the film was dried by passing through a drying room at a temperature of 60 ° C. and a humidity of 10% for 5 seconds. Than this,
The solid portion of the droplet is firmly adhered to the photosensitive layer to form a mat.

The specimens prepared as described above were identified by electron micrographs in the photographs and tables shown in FIGS.

In the discrimination, at least 50 mats were selected at random, their adhesion was evaluated, and the number of mats with peeling was inspected, and the occurrence rate of peeling was expressed by%.
As can be seen from the experimental results, the droplet diameter of the mat is 16 μm to 40 μm, and the surface temperature of the photosensitive lithographic printing plate is 7 ° C.
When the temperature is in the range of -37 ° C, a mat without peeling can be obtained.

Here, the manufacturing process of the PS plate will be described.

The PS plate is a JIS containing 99.5% by weight of aluminum, 0.01% by weight of copper, 0.03% by weight of titanium, 0.3% by weight of iron, and 0.1% by weight of silicon.
-A1050 rolled sheet of aluminum material with a thickness of 0.30 mm was converted to 400 mesh pumice stone (manufactured by Kyoritsu Ceramics).
Weight percent aqueous suspension and a rotating nylon brush (6,10-
(Nylon) and the surface was grained, and then washed well with water.

This was immersed in a 15% by weight aqueous solution of sodium hydroxide (containing 4.5% by weight of aluminum), etched so that the amount of aluminum dissolved was 5 g / m ² , and washed with running water. Furthermore, neutralize with 1% by weight nitric acid,
Next, in a 0.7% by weight nitric acid aqueous solution (containing 0.5% by weight of aluminum), a rectangular wave alternating waveform voltage (current ratio r = 0.9) having an anode voltage of 10.5 volts and a cathode voltage of 9.3 volts was used.
0, a current waveform described in Examples of JP-B-58-5796), and an electrolytic surface roughening treatment was carried out at an anode electricity amount of 160 coulomb / dm ² . After washing with water,
It was immersed in a 0% by weight aqueous sodium hydroxide solution, etched so that the amount of aluminum dissolved was 1 g / m ² , and washed with water. Next, it was immersed in a 50% by weight aqueous solution of 30% by weight sulfuric acid, desmutted and washed with water.

Further, a porous anodic oxide film forming treatment was carried out in a 20% by weight aqueous sulfuric acid solution (containing 0.8% by weight of aluminum) at 35 ° C. using a direct current. That is, electrolysis was performed at a current density of 13 A / dm ² , and the anodic oxide film weight was adjusted to 2.7 g / m ² by adjusting the electrolysis time. To prepare a negative photosensitive lithographic printing plate using a diazo resin and a binder, the support was washed with water, immersed in a 3% by weight aqueous solution of sodium silicate at 70 ° C. for 30 seconds, washed with water and dried.

[0032] The thus-obtained aluminum support, reflection density was measured with Macbeth RD920 reflection densitometer 0.30, the center line average roughness R _a as defined in JIS B00601 is 0.58μm met Was.

Next, methyl methacrylate /
A 1.0% by weight aqueous solution of ethyl acrylate / 2-acrylamide-2-methylpropane sodium sulfonate copolymer (average molecular weight: about 60,000) (molar ratio: 50/30/20) was dried by a roll coater to obtain an applied amount of 1.0% by weight. 0.05g
/ M ² .

Further, the following photosensitive solution-1 was applied using a bar coater and dried at 110 ° C. for 45 seconds. The dry coating amount was 2.0 g / m ² . Photosensitive solution-1 Diazo resin-1 0.50 g Binder-1 5.00 g Stylite HS-2 (manufactured by Daido Kogyo Co., Ltd.) 0.10 g Victoria Pure Blue BOH 0.15 g Tricresyl phosphate 0.50 g Dipicolinic acid 0 .20 g FC-430 (Surfactant manufactured by 3M) 0.05 g Solvent 1-methoxy-2-propanol 25.00 g Methyl lactate 12.00 g Methanol 30.00 g Methyl ethyl ketone 30.00 g Water 3.00 g The above diazo resin-1 Is obtained as follows. First, 29.4 g of 4-diazodiphenylamine sulfate (purity: 99.5%) was added at 25 ° C to 96% sulfuric acid 70%.
ml and stirred for 20 minutes. to this,
3.26 g of paraformaldehyde (purity 92%)
The mixture was gradually added over 0 minutes, and the mixture was stirred at 30 ° C. for 4 hours to allow the condensation reaction to proceed. The condensation molar ratio between the diazo compound and formaldehyde is 1: 1. The reaction product was poured into 2 liters of ice water with stirring, and treated with a cold concentrated aqueous solution in which 130 g of sodium chloride was dissolved. The precipitate is collected by suction filtration, the partially dried solid is dissolved in one liter of water, filtered, cooled on ice and washed with potassium hexafluorophosphate 23.
g was dissolved in an aqueous solution. Finally, the precipitate was collected by filtration and air-dried to obtain 1 g of diazo resin.

Binder-1 is 2-hydroxyethyl methacrylate / acrylonitrile / methyl methacrylate / methacrylic acid copolymer (weight ratio 50/20/26 /
4, average molecular weight 75,000, acid content 0.4 meq /
g) is a water-insoluble, alkaline water-soluble film-forming polymer.

Stylite HS-2 (manufactured by Daido Industry Co., Ltd.)
Is a polymer compound having a higher oil sensitivity than the binder,
It was a copolymer of styrene / mono-4-methyl-2-pentyl maleate = 50/50 (molar ratio), and the average molecular weight was about 100,000.

[0037]

According to the present invention, the mat can be prevented from peeling and no powder is generated by keeping the spherical diameter of the droplet and the surface temperature of the photosensitive lithographic printing plate in an appropriate relationship.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a method for manufacturing a photosensitive lithographic printing plate according to an embodiment.

FIG. 2 is an explanatory diagram showing a mat formed on a photosensitive lithographic printing plate.

FIG. 3 is an explanatory diagram conceptually illustrating a flying state of a droplet.

FIG. 4 is a photograph showing a peeled state of a mat.

FIG. 5 is a table showing a rate of occurrence of peeling of a mat.

FIG. 6 is a conceptual diagram showing a relationship between a photosensitive lithographic printing plate and a photographic original plate.

[Explanation of symbols]

 m matt L droplet 10 photosensitive lithographic printing plate

Claims (1)

[Claims] 1. A method of manufacturing a photosensitive lithographic printing plate, wherein an aqueous liquid is sprayed as fine droplets onto a photosensitive layer of the photosensitive lithographic printing plate to electrostatically adhere to the photosensitive layer to form a mat. When the temperature of the photosensitive lithographic printing plate is 7 ℃ ~
A method for producing a photosensitive lithographic printing plate, wherein the temperature is adjusted so as to be in a range of 37 ° C., and the sphere diameter of a droplet at the time of jetting is set to 16 μm or more and 40 μm or less.