JPH0470658A - Processing method for waterless planographic printing plate - Google Patents

Abstract

PURPOSE:To prevent a stain, the void of a solid part or a pin hole, etc., occurring in printing by eliminating the waste of silicon rubber, etc., attached on a plate by imparting rubbing by a brush after completing developing essentially. CONSTITUTION:In a process to automatically perform the carrying and processing of a waterless planographic printing plate in which a primary layer, a photosensitive layer, and a silicon rubber layer are laminated on a pair of supporting bodies in the above sequence after exposing, the rubbing by the brushes 21-24 is imparted on the plate after exposure and the developing are completed essentially. In such a case, when the rubbing by the brushes 21-24 is imparted, it is enough to set the strength of the brushes at a range not to change picture quality in the reproducibility of a dot and the number of steps of the solid part, etc. Thereby, it is possible to prevent the stain, the void of the solid part, and the pin hole, etc., in the printing occurring by eliminating the waste o the silicon rubber, etc., attached on the plate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for processing a waterless lithographic printing plate, and more specifically, it relates to a method for processing waterless lithographic printing plates, and more specifically, a method for removing scum and the like attached to a silicone rubber layer after development. This invention relates to a method for processing waterless lithographic printing plates.

[Background of the Invention] Conventionally, waterless lithographic printing plates (also referred to as photosensitive lithographic printing plates that do not require dampening water) are known in which a photosensitive layer and an ink repellent layer are sequentially coated on a support. . By exposing and developing this waterless planographic printing plate, a planographic printing plate that can be printed without using dampening water can be obtained.

Such a waterless lithographic printing plate is produced, for example, by
As described in No. 2781, the unexposed area (image area) of the photosensitive layer is dissolved using an aqueous developer, and the upper silicone rubber layer is removed accordingly.
As described in No. 26923, the exposed area (non-image area) is firmly adhered to the photosensitive layer by photoadhesion, and the unexposed area (image area) is removed using an organic solvent that swells only the silicone rubber layer. There is.

With these types of waterless lithographic printing plates, when the lithographic printing plate obtained after completing a series of processes including development is subjected to printing, spot-like ink stains and white spots in solid areas may occur. There was a problem.

Therefore, the inventors of the present invention continued their intensive research in order to solve the above-mentioned problems. As a result, the silicone rubber residue in the image area that had been rubbed off by the brush during the development process re-adhered to the plate surface. It was discovered that when something present on the plate adheres, when it is transferred from a roll, when it is scraped off with a brush and then remains attached, it may re-adhere and remain on the plate surface even after processing. Based on these findings, we were able to complete the present invention.

[Object of the Invention] Therefore, the object of the present invention is to provide a waterless lithographic printing plate which removes silicone rubber residue etc. adhering to the plate surface and prevents the occurrence of stains, white spots in solid areas, bone holes, etc. during printing. The purpose is to provide a processing method.

[Structure of the Invention] The object of the present invention is to automatically transport a waterless lithographic printing plate in which a primer layer, a photosensitive layer and a silicone rubber layer are laminated in this order on a support after exposing the plate to light; This is achieved by a method for processing a waterless lithographic printing plate, which is characterized in that, in the processing step, rubbing with a brush is applied after the development is substantially completed.

Below, the configuration of the present invention will be explained in more detail.

The present invention is characterized in that a waterless lithographic printing plate is exposed and developed, and after the development is substantially completed, it is rubbed with a brush, thereby removing the silicone rubber adhering to the plate surface. It has the excellent effect of preventing stains, white spots in solid areas, bone holes, etc., from occurring during printing.

As used herein, "development is substantially completed" refers to the following cases.

Generally, when developing a waterless lithographic printing plate with a silicone rubber layer coated on the photosensitive layer, the silicone rubber layer in the image area is peeled off and removed by rubbing the silicone rubber layer of the printing plate. be exposed. In this case, the stronger the rubbing, the better the halftone dot reproducibility and the developability of the solid areas, but if the rubbing is applied too much, the halftone dot reproducibility will decrease, and the collapse of the shadow areas will become especially noticeable. . Based on this point, in automatic developing machines for waterless planographic printing plates,
Processing is performed after setting appropriate conditions for brush scrubbing. Here, "development is substantially completed" means that development is completed under the set conditions.

In the present invention, when applying rubbing with a brush,
The strength of the brush is an important factor, but the strength of the brush may be within a range that does not change the image quality in terms of halftone dot reproducibility, number of steps in solid areas, etc.

Specifically, the strength of the brush can be changed depending on the peripheral speed of the outer diameter of the brush roll, the pressure on the plate surface, the length, thickness, and material of the brush bristles, but this brush is used after development is completed. Therefore, the strength of the brush is preferably within a range that does not have the effect of promoting development.

Furthermore, the scrubbing strength of the brush can be varied depending on the following factors:

1) Strength of the bristles Material, length and thickness of the bristles 2) Pressure on the printing plate (brush pressure) Brush pressure = R-L (R: radius of the brush roll, L: distance from the rotation axis of the brush roll to the printing plate 3) Brush roll outer diameter 4) Brush roll rotation circumferential speed Brush roll rotation circumferential speed = 2πrZ (Z: rotation speed) 5) Flocked shape of brush bristles 6) Rubbing time Number of brushes, conveyance speed 7) Brush Flocking density of the bristles In the above, synthetic fibers such as nylon, polyester, polyvinyl chloride, polyvinylidene chloride, polyethylene, polypropylene, and polybutyl terephthalate (PBT) are used as materials for the brush, but they have elasticity, rigidity,
Considering abrasion resistance, heat resistance, chemical resistance, water absorption, hygroscopicity, etc., nylon 6, nylon 6/6, nylon 6/10, nylon 6/12, and PBT are preferable, and nylon 6 is more preferable.・12, PBT.

There are two types of flocked brushes: channel roll brushes in which a channel-shaped roll is wrapped around a pipe, and implantable roll brushes in which small holes are made in a core material such as polyvinyl chloride and the bristles are implanted. Both can be used, but the implantable type is preferable to apply stronger scrubbing. Moreover, it is more preferable to form the implantation pitch in a spiral shape with respect to the roll.

On the other hand, when durability is considered, a channel roll type brush is preferable.

The brush for removing residue used in the present invention has the following differences compared to the brush for development.

Since it is necessary to remove the silicone rubber layer in the image area with a developing brush, it is necessary to rub it strongly enough not to damage the silicone rubber layer in the non-image area.

On the other hand, brushes for removing silicone rubber residue are used to remove silicone rubber residue that has adhered to the plate surface, so although they require a certain degree of strength, they do not have the effect of accelerating development. A certain degree of strength is required, and if it has the effect of accelerating development, it will cause new scum to be generated, which is not preferable.

Here, the preferred embodiments of the rubbing strength factors are shown in the table, but strictly speaking, the selection of the rubbing strength factors varies depending on the peel strength of the silicone rubber layer, the scratch resistance, the characteristics of the developer, etc. The decision must be made after considering the conditions.

The brush process for removing silicone rubber residue used in the present invention can be used between or after any process as long as the silicone rubber in the image area is removed and development is substantially completed. Often, it is preferably provided before and after post-processing steps such as washing with water after development and dyeing, in which case,
Furthermore, it is preferable to provide a filter in the piping system or the like.

The brush for removing silicone rubber residue used in the present invention is preferably rotated in the opposite direction.

In the present invention, as the layer removed by development, there are cases where only the silicone rubber layer is removed and cases where the photosensitive layer and the silicone rubber layer are removed, but the method of the present invention can be carried out using either of these. can do.

As the photosensitive composition used in the present invention, any known photosensitive composition can be used, but diazo resins and photopolymerizable compounds are preferably used, and diazo resins are particularly preferred.

The photosensitive composition will be specifically explained below.

(1) Photosensitive composition containing diazo resin The diazo resin used in the present invention includes various types, but is preferably a diazo resin typified by a condensate of p-diazodiphenylamine and formaldehyde,
Those that are water-insoluble and soluble in organic solvents are used, preferably those that are water-insoluble and soluble in ordinary organic solvents as described in Japanese Patent Publications No. 47-1167 and Japanese Patent Publication No. 57-43890. Particularly preferably, the following general formula [1
] It is a diazo resin shown by.

The following is a general formula [I] in which RI R2 and R3 represent a hydrogen atom, an alkyl group, or an alkoxy group, and R4 represents a hydrogen atom, an alkyl group, or a phenyl group.

X represents PFa or BF4, and Y represents -NH--S- or -0-. ] Examples of the diazo monomer in the diazo resin used in the present invention include 4-diazo-diphenylamine, 3
-methoxy-4-diazodiphenylamine, 3-ethoxy-4-diazodiphenylamine, 3-(n-propoxy)-4-diazodiphenylamine, 3-(isopropoxy)-4-diazodiphenylamine, and the like.

Examples of the aldehyde used as a condensing agent with the diazo monomer include formaldehyde, adetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, and benzaldehyde.

Furthermore, water-soluble diazo resins can be obtained by using chloride ions, tetrachlorozinc acid, etc. as anions, and boron tetrafluoride, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 4.4° -biphenyldisulfonic acid, 2,5-dimethylbenzenesulfonic acid,
By using 2-nitrobenzenesulfonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, etc., an organic solvent-soluble diazo resin can be obtained. Particularly preferably, a diazo resin made of hexafluorophosphoric acid is used.

The diazo resin is preferably used in combination with a film-forming resin, particularly a lipophilic polymer compound having a hydroxyl group. Examples of such lipophilic polymer compounds include copolymers of 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate and other copolymerizable mercury having an aliphatic hydroxyl group in the side chain. can be mentioned. In addition to these, polyvinyl butyral resin, polyurethane resin, polyamide resin, epoxy resin,
Novolak resin, natural resin, etc. may be added.

Various polymeric compounds can be used as the binder used in combination with this diazonium salt, but preferably,
A monomer having an aromatic hydroxyl group as described in Japanese Patent No. 4-98613, such as N-(4-hydroxyphenyl)acrylamide, N-(4-hydroxyphenyl)methacrylamide, o+, m+, or p - copolymers of hydroxystyrene, o+, m+, or p-hydroxyphenyl methacrylate, etc., with other monomers, hydroxyethyl acrylate units as described in U.S. Pat. No. 4,123,276; Polymers containing hydroxyethyl methacrylate units as the main repeating unit Natural resins such as shellac and rosin, polyvinyl alcohol, polyamide resins described in U.S. Pat. No. 3,751,257, and U.S. Pat.
．． 660,097, linear polyurethane resins, polyvinyl alcohol phthalate resins, epoxy resins condensed from bisphenol A and epichlorohydrin, alkali-soluble resins such as novolac resins, and vinyl-based resins having phenolic hydroxyl groups. Examples include polymers, condensation resins of polyhydric phenols and aldehydes or ketones described in JP-A-55-57841, and the like. Examples of the novolac resin include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensation resin as described in JP-A-55-57841, and phenol-cresol-formaldehyde copolycondensation resin as described in JP-A-55-127553. Examples include copolycondensation resins of p-substituted phenol and phenol or cresol and formaldehyde as described above.

In addition to the above-mentioned materials, these photosensitive compositions may also contain colorants such as dyes and pigments, sensitizing agents, plasticizers, surfactants, organic acids, acid anhydrides, and acids that can be removed by exposure to light. Compounds that may be generated can be added.

These binders are present in an amount of 10 to 95% in the solid content of the photosensitive composition.
It is contained in an amount of 40 to 80% by weight. The diazo resin is contained in an amount of 5 to 80% by weight, preferably 15 to 60% by weight.

Other dyes, pigments such as pigments, fat-sensitizing agents, plasticizers, surfactants, etc. can be added to these photosensitive compositions.

(2) Photosensitive composition containing a polymer compound having 10H-C)I-C group in the main chain or side chain of the polymer. Those based on photosensitive polymers such as polyesters, polyamides, and polycarbonates containing 10H-CH-C- as a photosensitive group in the chain (for example, U.S. Pat.
030,208, 343°707.373 and 3,453.237);
Those based on photosensitive polyesters derived from malonic acid compounds and difunctional glycols (e.g., U.S. Pat. No. 2,956.878 and U.S. Pat. No. 3,173.7)
87); cinnamate esters of hydroxyl-containing polymers such as polyvinyl alcohol, starch, cellulose, and the like (e.g., U.S. Pat. No. 2,690,966); , No. 2,752, 3
Photosensitive polymers such as those described in No. 72, No. 2,732,301, and the like.

These photosensitive compositions may contain other sensitizers, stabilizers, plasticizers, pigments, dyes, and the like.

(3) Photopolymerizable composition comprising an addition polymerizable unsaturated compound This composition preferably comprises (a) a vinyl monomer having at least two ethylenically unsaturated double bonds; (b) photopolymerizable It consists of an initiator and (C) a polymer compound as a binder resin.

The vinyl monomer of this component (a) is
No. 5093, No. 35-14719, No. 44-2872
It is described in each publication No. 7.

Acrylic or methacrylic acid esters of polyols, such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, or methylene bis(meth)acrylamide , bis(meth)acrylamides such as ethylene bis(meth)acrylamide, or unsaturated monomers containing urethane groups, such as di(2'-methacryloxyethyl)-2,4-tolylene diurethane, di( Examples include reaction products of diol mono(meth)acrylate and diisocyanate such as 2-acryloxethyl)trimethylene diurethane.

As the photopolymerization initiator of component (b), for example, J
, carbonyl compounds, organic sulfur compounds, perfusates, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, etc., as described in Chapter 5 of "Light Sensitive Systems" by Kosar. . More specifically, British Patent No. 1,459,563
Disclosed in the issue.

Furthermore, various known polymers can be used as the binder resin (binder) of component (C). Furthermore, the polymer compounds mentioned above as binders for the diazo resin can also be preferably used. For details on specific binder resins, see
No. 4,072,527.

These photopolymerizable compositions contain thermal polymerization inhibitors, plasticizers,
It can contain dyes, pigments, etc.

A liposensitizing agent and a surfactant added to the photosensitive composition,
Additives such as sensitizers, stabilizers, thermal polymerization inhibitors, plasticizers, and pigments such as dyes and pigments are generally included in photosensitive coating solutions, although the amount added varies depending on the type. 0.01 to 20% by weight, preferably 0.05 to 20% by weight based on the photosensitive composition
10% by weight is suitable.

The ink repellent layer used in the present invention is not particularly limited as long as it has ink repellency, such as a silicone rubber layer used in this technical field.

In particular, it is preferable to use a condensation crosslinked silicone rubber layer.

The silicone rubber used in the present invention is a linear organic polymer having a repeating unit represented by the following general formula [I] and having a molecular weight of several thousand to several tens of blades and a hydroxyl group in the main chain or at the end of the main chain. Those containing siloxane as a main component are preferred.

General formula [1] % formula % where n is an integer of 2 or more, R is an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, an alkoxyl group, a vinyl group, an aryl group, a silanol group (0) 1 group) and
Preferably, 60% or more of R is a methyl group. The silanol group (O)l group) may be located either in the main chain or at the end of the main chain, but is preferably located at the end.

The silane coupling agent (or silicone crosslinking agent) used in the present invention is nn5jX<-n (wherein, n is an integer of 1 to 3, and R is alkyl, aryl, alkenyl or a combination thereof These groups may have functional groups such as halogen, amine, hydroxy, alkoxy, aryloxy, and thiol.

X is -0H1-〇R2, -0Ac, -o-N-c -C
1), -Br, - represents a substituent such as -, where 62, R
3 represents the same as R above, and R2 and R3 may be the same or different. Ai is also a silane compound represented by ), which represents an acetyl group.

That is, the silicone rubber useful in the present invention is obtained by a condensation reaction between such a silicone base polymer and a silicone crosslinking agent such as those listed above.

Specific examples of the silane coupling agent used in the present invention include )IN[(CHz)ssi(OMe)s]2, vinyltriethoxysilane, C12(C)12)3Sl(O
Me) a, CH35i (OAc) s, R5(CH
2) ssi(OMe)s, vinyltris(methylethylketoxime)silane, and the like.

The silicone rubber described above is also available as a commercial product, such as YE-3085 manufactured by Toshiba Silicone Co., Ltd. Other useful silicone rubbers can be produced by reacting the above-mentioned base polymer with a silicone oil having repeating units represented by the following general formula [II], or by reacting a silicone oil in which about 3% of R is a vinyl group. It can also be obtained by addition reaction of silicone with a base polymer or reaction of the silicone oils with each other.

(In the formula, R has the same meaning as R, which is a substituent of the polymer represented by the general formula [II, m is an integer of 2 or more, and n is an integer of 0 or 1 or more.) Through such a crosslinking reaction, To obtain silicone rubber, a crosslinking reaction is carried out using a catalyst. This catalyst includes tin, zinc, cobalt, lead,
Organic carboxylates of metals such as calcium, manganese, etc.
For example, dibutyltin laurate, tin(II) octoate, cobalt naphthenate, or chloroauric acid may be used.

Additionally, fillers can be mixed in to improve the strength of the silicone rubber and to obtain a silicone rubber that can withstand the frictional forces generated during printing operations. Silicone rubber mixed with filler in advance is commercially available as silicone rubber stock or silicone rubber dispersion, and when it is preferable to obtain a silicone rubber film by coating as in the present invention, RTV
Alternatively, dispersion of LTV silicone rubber is preferably used. An example of this is Syl Off 23.5RX-257,5H manufactured by Toray Silicone.
There are silicone rubber dispersions for paper coating such as 237.

In the present invention, it is preferable to use condensation and crosslinking type silicone rubber.

The silicone rubber layer preferably contains a silane coupling agent having an amino group in order to further improve adhesiveness.

Examples of preferable silane coupling agents include the following.

(a) 82NC82CI(2N)I (CI(2)
3Si (OCHa).

(b) 82NCE2G)12NH(CH2) ssi
(QC)Is) 2 (CL)(c) 82N (C
H2) ssr (OEt) s The silicone rubber layer used in the present invention can further contain a small amount of a photosensitizer.

The silicone rubber layer used in the present invention is prepared by dissolving silicone rubber in a suitable solvent, applying it onto the photosensitive layer, and drying it.

The support of the present invention is preferably one that is flexible enough to be set in a normal lithographic printing machine and that can withstand the load applied during printing, such as metal plates such as aluminum, zinc, copper, and steel, and metal plates such as chromium, zinc, Examples include metal plates plated or vapor-deposited with copper, nickel, aluminum, iron, etc., paper, plastic films, glass plates, resin-coated paper, and paper with exposed metal foils such as aluminum.

Among these, aluminum plates are preferred.

The treatment for the support itself to improve the adhesion is not particularly limited, and includes various surface roughening treatments.

The support has a primer layer, and the primer layer includes, for example, polyester resin, vinyl chloride-vinyl acetate copolymer, acrylic resin, vinyl chloride resin, polyamide resin, polyvinyl butyral resin, epoxy resin, acrylate copolymer. , vinyl acetate copolymers, phenoxy resins, polyurethane resins, polycarbonate resins, polyacrylonitrile butadiene, polyvinyl acetate, and the like.

In addition, as the anchor agent constituting the primer layer,
For example, the above-mentioned silane coupling agent, silicone primer, etc. can be used, and organic titanates and the like are also effective.

The thickness of each layer constituting the plate material of the present invention is as follows. That is, the support has a thickness of 50 to 400 μm, preferably 100 μm.
~300 uttr% photosensitive layer is 0.05-10 μm
, preferably 0.5 to 5 μm. The silicone rubber layer has a thickness of 0.5 μm to 5 μm.
The thickness is 1 to 10 μm, preferably 0.5 to 2 μm.

In the present invention, a protective layer may be provided on the upper surface of the silicone rubber layer, if necessary.

The following margins [Examples] The present invention will be described below with reference to Examples, but the present invention is not limited to these.

In the examples, parts refer to parts by weight.

Example 1 A primer layer with the following composition was coated on a smooth aluminum plate degreased by the usual method so that the film thickness after curing was 4.0 μm. After drying, a high-pressure mercury lamp (output aow/c) was applied.
m).

The curing time is 60 seconds including drying time.

[Primer layer composition] Epoxy 5P-1509 (manufactured by Showa Kobunshi Co., Ltd., bisphenol A-based epoxy acrylate) 100 parts Trimethylolpropane triethoxy triacrylate 80 parts 2,4-diethylthioxanthone 4 parts p-dimethylaminobenzoic acid ethyl ester 4 parts Propylene glycol monomethyl ether 600 parts [Photosensitive composition (1) Diazo resin - 140 parts (2) 2-hydroxyethyl methacrylate, N-(4
-Hydroxyphenyl) methacrylamide and acrylic acid in a molar ratio of 50/47/3 copolymer
50 parts (3) Victoria Pure Blue BOH (dye manufactured by Odugaya Kagaku Co., Ltd.) 1 part (4) Methyl cellosolve 900 parts Synthesis of Diazo Resin-1 Diazo Resin-1 was synthesized as follows.

14.5 g (50 mmol) of p-diazodiphenylamine sulfate was dissolved in 40.9 g of concentrated sulfuric acid under water cooling.

To this reaction solution, 1.35 (45 mmol) of paraformaldehyde was slowly added so that the reaction temperature did not exceed 10°C.

This reaction mixture was added dropwise to 500 ml of ethanol under water cooling, and the resulting precipitate was filtered. After washing with ethanol, this precipitate was dissolved in 100 ml of pure water, and 6.8
A cold concentrated aqueous solution of 1 g of zinc chloride was added. After filtering the resulting precipitate, it was washed with ethanol, and then washed with 150
Dissolved in ml pure water. To this liquid was added a cold concentrated aqueous solution in which 8 g of ammonium hexafluorophosphate was dissolved. The resulting precipitate was collected by filtration, washed with water, and dried to form a diazo resin.
I got 1.

Next, the following silicone rubber composition was coated on the photosensitive layer at a dry weight of 2.0 g/m''.
It was dried at ℃ for 10 minutes to obtain a lithographic printing plate material that did not require dampening water.

[Silicone rubber layer composition] Dimethylpolysiloxane having hydroxyl groups at both ends (molecular weight 52,000) 100 parts Triacetoxymethylsilane, 10 parts Dibutyltin laurate 0.8 parts Isopar G (manufactured by Esso Chemical) 900 parts The above plate material After vacuum-adhering a positive film to the top surface of the film, it was exposed to light using a metal halide lamp as a light source.

Next, development and dyeing were performed using the processing apparatus shown in FIG. Three wooden brush rolls placed during the development process, 21.2
No. 2.23 used rolls with an outer diameter of 80 mm, brush bristles with a thickness of 0.2 o+m, and a bristled length of 12+ nm. In addition, the brush pressure defined in the above specification is 1.5
Adjusted to mm.

The brushes for removing residue are installed at the positions of the last brushes for the washing steps B and D, the dyeing step C, and the developing step. The conditions at this time are, for example, in the case of a water washing process, the roll outer diameter is 4
0 mm, brush bristles thickness 0.08 mm, bristles length 1
A 2mm brush roll 24 is placed and the brush pressure is set to 0.3.
It was set to mm.

The brush bristles are made of nylon 6 in both rolls.
12 was used.

The peripheral speed of rotation of the brush during processing is brush roll 21.22
．． 23, the speed was adjusted to 120 m/min, and the brush roll 24 was adjusted to 30 m/min. Further, the brush rolls 21, 22, and 23 were rotated so as to rub the plate surface in the same direction as the conveyance direction of the printing plate, and the brush roll 24 was rotated in the opposite direction. The conveyance speed of the printing plate during processing was 10 a+m/sec, and the developing time was 70 seconds and the dyeing time was 18 seconds.

The developer is Konica's positive PS plate developer 5DR-1,
3J! The solution was diluted 6 times with water, and the temperature was adjusted to 27°C before use.

Composition 201 below was used as the staining solution.

[Staining solution composition] Crystal violet 0.5 parts Benzyl alcohol 4.5 parts Nonionic surfactant (polyoxyethylene alkyl ether H
L B: 17.0) 3.0 parts water
10
15 J2 of water was prepared in each of the first and second washing parts. The temperature of the washing water and dyeing solution during treatment was 25°C.

When the processing method of the present invention was carried out using the above-mentioned processing apparatus and the Kikuzen size 100 waterless planographic printing plate was processed, the silicone rubber layer and photosensitive layer in the image area were removed and exposed. A good printing plate with a dyed primer layer was obtained.

When this printing plate was observed, no dust, dregs, etc. were observed, and there were no pinhole-like ink stains or white spots on the printed matter.

Example 2 The brush roll 24 shown in FIG. 1 was rotated at a circumferential speed of 30 m.
The process was carried out in exactly the same manner as in Example 1, except that the rotation was performed in the opposite direction to that in Example 1 at a speed of /min.

The image quality of the printing plates after the treatment was the same as in Example 1, and good results were obtained, but out of 100 plates, 5 plates had 1 or 2 small silicone rubber particles attached. However, this was quickly removed after printing started and did not actually become a problem.

Comparative Example 1 Except for removing the brush roll 24 shown in FIG.
The treatment was carried out in exactly the same manner as in Example 1.

The image quality of the printing plates after the treatment was no different from that of Example 1, and good results were obtained, but out of 100 plates, about 70 plates had silicone rubber residue attached to them. In many cases, countless pieces of silicone rubber were attached to solid areas and non-image areas. Approximately 20 of these printing plates remained unremoved during printing, and stains and white spots in solid areas caused by these plates were observed.

Comparative Example 2 The brush roll 24 shown in FIG. 1 was changed to one with a brush roll diameter of 40 mm, brush bristles thickness of 0.2 mm, and bristles length of 7 mm, brush pressure of 0.8 mm, and rotational circumference. The speed was adjusted to 80 m/win.

Otherwise, the same process as in Example 1 was performed, and a printing plate with slightly crushed shadows compared to Example 1 was obtained. Half of the 100 plates had silicone rubber residue attached to them, and about 10 of them had pinhole-like stains or solid white spots in printing.

Example 3 As shown in Fig. s2, the brush roll 24 used in the washing process of Example 1 was removed, and instead, this roll was used in the dyeing process under exactly the same conditions as the brush roll 24 of Example 1. Installed and rotated.

The results of the printing plate after the 100 plate treatment were as good as in Example 1.

Example 4 Brush rolls 23 and 24 shown in FIG. 1 were removed, and a brush roll 24 was installed in the position of brush roll 23.

Brush rolls 21 and 22 have a peripheral rotational speed of 120 m/min.
The brush roll 24 was rotated in the same direction as in Example 1 at a brush pressure of 1.5+am, and the brush roll 24 was rotated in the opposite direction to the brush rolls 21 and 22 at a rotation peripheral speed of 30 m/win and a brush pressure of 0.3+am.

The conveyance speed was 15@m/sec, and the development time was 105 seconds.

The process was carried out in exactly the same manner as in Example 1 except for the above changes.

A printing plate with no difference in image quality from Example 1 was obtained.

Although a small amount of silicone rubber residue adhered to 10 of the 100 plates, this amount of residue was removed during actual printing and did not pose a substantial problem.

Comparative Example 3 The process was carried out in exactly the same manner as in Example 4, except that the brush roll 24 was removed. Although there was no difference in image quality from Example 4, similar to Comparative Example 1, silicone rubber residue was observed adhering to the plate surface, which caused a printing problem.

[Effects of the Invention] The present invention makes it possible to remove residues of silicone rubber, etc. adhering to the printing plate by applying rubbing with a brush in the process after the development is substantially completed. The obtained printing plate can provide excellent printed matter without pinhole stains or solid white spots during printing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an automatic development processing machine having a developing process A, a first washing process B, a dyeing process C, and a second washing process used in the present invention. FIG. 2 is a sectional view showing an automatic processing machine in which a brush for removing residue is installed in the dyeing process. Explanation of symbols 1: Passage of lithographic printing plate or lithographic printing plate 21.22.2
3.24... Brush roll 3... Roller 31.
・Skewer roll 4・・Tray 51・・Developer shower 52.54.55・Wash water shower 53・・Staining solution shower 61.62.63・・Filter 7・・Pump A・・Developing process B・・No. 1 Washing process C... Dyeing process D... 2nd washing process Applicant Koni
Miki Nakajima, Agent Patent Attorney Co., Ltd.
1 Yugai

Claims (1)

[Claims] After exposing a waterless lithographic printing plate in which a primer layer, a photosensitive layer and a silicone rubber layer are laminated in this order on a support, the printing plate is automatically conveyed and processed. A method for processing a waterless lithographic printing plate, which comprises applying rubbing with a brush after the process is substantially finished.