JPH01312556A - Photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To improve developability and image reproducibility by treating the surface of a base with the sol of the compd. of metal. CONSTITUTION:After the surface of the iron material of the iron base is roughened, the surface is subjected to plating or a chemical conversion treatment after the plating and is further treated with the sol of the compd. of the metal. Namely, various ordinary methods, for example, a mechanical method, chemical method, and method by electrolysis are used for the method of roughening the surface of the iron material. Ni, Cr, Cu or Sn having a rust inhibitive effect to the iron material is used in the plating treatment after the surface roughening. A chemical conversion treatment method by immersion into a soln. contg. chromate, dichromate, phosphate or the like or by an electric field in said soln. is used for the chemical conversion treatment to be executed at need after the plating. The sol of the compd. of the metal consists of an oxide or hydrate and the metals to form such sol are preferably Al, Cr, Ni, and Zn. A cathodic electrolysis or immersion treatment is executed in the aq. soln. contg. the sol of the compd. of the metal as such hydrophilicity impartation treatment method. The developability and image reproducibility are improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive lithographic printing plate made by electrophotography.

[Background of the invention]

Various methods are known for producing lithographic printing plates using electrophotography, and aluminum plates are used as supports for the printing plates. For example, Japanese Patent Publication No. 51-25761 discloses that a zinc oxide photoconductive layer is provided on an aluminum plate, a toner image is formed thereon by electrophotography, and then the zinc oxide layer in the non-image area is subjected to a hydrophilic treatment to form a lithographic plate. A method of making a printing plate is disclosed. In addition, special public service No. 46-39405
No., JP-A No. 52-2437, etc. discloses that an oxazole-alkali soluble resin layer is provided on a grained aluminum plate or an anodized aluminum plate after toner image formation, and then the non-image area is coated with a grained aluminum plate. A method is disclosed in which a printing plate is formed by dissolving and removing an alkali solution. Furthermore, Japanese Patent Application Laid-Open No. 54-144203 discloses that a toner image formed on a zinc oxide photoconductive layer is transferred to a transfer printing plate having an epoxy resin layer provided on a brush-polished and anodized aluminum plate, A method is described in which, after heat fixing, the epoxy resin layer in the non-image area is eluted with a solvent to create a lithographic printing plate.

As described above, the conventional technology has the disadvantage of having to use expensive aluminum, and furthermore, after graining using mechanical, chemical, or electrochemical methods,
Because anodizing is an important process, it must be done carefully.
Moreover, it required advanced technology, and at the same time had the drawback of being time-consuming and low production efficiency.

For this reason, iron materials have been developed as supports for photosensitive planographic printing plates, which have characteristics such as being inexpensive, having high mechanical strength, and being magnetic.

For example, JP-A No. 55-145193, JP-A No. 58-220
As described in No. 796 and No. 59-31192, an iron support having a chromium electrodeposited layer, JP-A-56
-130395, 56-130396, 56-
As described in Japanese Patent No. 150592 and Japanese Patent No. 57-64597, iron supports whose surfaces are roughened by electroforming are known.

In addition, in order to improve the hydrophilicity of the iron support,
As described in No. 8-220797 and No. 59-11294, a hydrophilic treatment method is known in which treatment is performed with a mixed aqueous solution of a water-soluble polymer and a water-soluble metal salt or an aqueous potassium permanganate solution.

However, photosensitive plain printing plates produced using these iron supports have the disadvantage of poor appearance and image reproducibility.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide a photosensitive lithographic printing plate which is made by electrophotography and has good developability and image reproducibility.

[Means to solve the problem]

The above-mentioned object of the present invention is to provide a photosensitive planographic printing plate that is plate-made using an electrophotographic method, in which the support of the photosensitive planographic printing plate is a support whose surface is treated with a sol of a metal compound. Accomplished by edition.

The present invention will be explained in detail below.

The iron support of the present invention is obtained by roughening the surface of an iron material, subjecting it to plating or post-plating annealing treatment, and further treating it with a sol of a metal compound.

The iron material in the present invention includes not only pure iron but also alloys of iron and other elements. Other elements that form alloys with iron include carbon,
Examples include manganese and nickel. Examples of alloys include alloys of carbon #i (0.04% to 1.7% carbon) and iron), cast iron, which has a higher carbon content than carbon steel, and other elements (e.g., manganese, 2.7 K). , chromium, cobalt, tungsten, molybdenum) (for example, manganese steel, nickel steel, chromium steel, nickel-chromium steel). The above-mentioned carbon steels include extremely mild steel (carbon 0.25% or less), soft* (0.25-1.0%), hard steel (carbon 0.5-0.1%), and extremely hard steel (carbon 1.0%). .0% or more).

Various conventionally known methods can be used to roughen the surface of the iron material, including mechanical methods, chemical methods, and electrolytic methods. Examples of mechanical methods include a ball polishing method, a brush polishing method, and a polishing method using liquid honing.

Chemical methods include etching with a solution containing sulfuric acid, phosphoric acid, nitric acid, dioxalic acid, pyrophosphoric acid, ferric chloride, etc. The electrolytic method includes an electrolytic etching method and an electrolytic plating method.

In the plating treatment after the surface has been roughened, Ni, Cr, Cu, or Sn, which has a rust-preventing effect on iron materials, is used.

Note that the plating metal is not limited to the above-mentioned single metal, but also includes an alloy containing one or more of these metals, or a composite plating of two or more of these metals.

Chemical conversion treatment performed as necessary after plating is chromate,
dichromate, phosphate, molybdate, borate,
There are chemical conversion treatment methods, such as immersion in a solution containing perborate or the like, or using an electric field in the solution.

The center line average roughness (shown in D I N4768) of the support surface obtained by processing as described above is:
0.1 to 3 μm, preferably 0.3 to 0.5 μm
It is.

The treatment performed after plating with a sol of a metal compound is a hydrophilic treatment, and this treatment may be applied to both the front and back sides of the support.

A sol of a metal compound is composed of an oxide or a hydrate, and examples of the metal that forms such a sol include A.
Il, Ti, Zr, Cr, Ni, Zn, Sn, Mn
, Cu, Go, Fe.

There are Pb, Cd, Mg, Ca, etc., and in the present invention, at least one kind of sols of compounds of these metals is used, and A(2, Cr, Ni, and Zo are preferably used).

As the hydrophilic treatment method, cathodic electrolysis or immersion treatment is preferably performed in an aqueous solution containing a sol of the metal compound. The concentration of sol of metal compound in aqueous solution is 1-100
g/Q is preferred. Additionally, inorganic salts such as chromic acid, phosphoric acid, and sulfuric acid, organic acids such as citric acid and acetic acid, or surfactants can be added to the treatment solution to improve the stability of the sol in an aqueous solution. .

The cathode electrolysis conditions vary depending on the type of sol used, but the current density is 0.5 to IOA/d+a'', the treatment temperature is 5 to 50°C, and the treatment time is 1 to 60 seconds.

The photoconductive layer used in the present invention is a layer containing a photoconductor, and the photoconductor used is at least one of an inorganic photoconductor, an organic photoconductor, or a photoconductive organic pigment. is used. As the inorganic photoconductor, for example, selenium-based, zinc oxide-based, cadmium sulfide, etc., which are known in electrophotography, are used. Examples of organic photoconductors include polyvinylcarbazoles, oxazoles, and biryllium salts. Examples of photoconductive organic pigments used include phthalocyanine pigments and quinacridone pigments.

Dye sensitizers or chemical sensitizers described in Japanese Patent Publication No. 40-7333, Japanese Patent Application Laid-Open No. 54-134632, etc. can be used. The photoconductor (and sensitizer) is dissolved or suspended in a solution containing at least one natural or synthetic polymeric substance (for example, styrene resin, silicone resin, phenolic resin, etc.) using a known method. can be provided on a support. Additionally, various additives can be added to the photoconductive layer. For example, a surfactant to improve coating properties, a plasticizer to impart flexibility and abrasion resistance to the coating film, etc. can be added. Furthermore, an intermediate layer (1, made of, for example, polyvinyl alcohol, ethyl cellulose, polyacrylic acid, etc.) may be provided between the support and the photoconductive layer, if necessary, for the purpose of improving electrophotographic properties.

The photoconductor is prepared by mixing one or more of the above natural or synthetic polymeric substances with ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, toluene, tetrahydro7rane, dimethylformamide, dioxane, or a mixed solvent thereof. 1 to 50 μ, preferably 1 to 15
The coating is coated to a thickness of μ and dried to obtain a photosensitive planographic printing plate.

In the present invention, conventionally known methods can be used to obtain a lithographic printing plate using electrophotography.

Typical methods include: (1) A method in which a photoconductive layer is provided on the support according to the present invention, a toner image is formed by electrophotography, and then the photoconductive layer in non-image areas is subjected to hydrophilic treatment.

(2) A method of providing a photoconductive layer on a support according to the present invention and forming a toner image by electrophotography, and then removing the photoconductive layer in a non-image area; and (3) a method of forming a toner image on the photoconductive layer. After forming the toner image, the toner image is transferred onto a polymer layer provided in advance on the support according to the present invention, and after heat fixing, the resin layer in the non-image area is removed.

The lithographic printing plate of the present invention obtained by the method (1) has a photoconductive layer on the support according to the present invention, and further has a toner image on the photoconductive layer in the image area.

The photosensitive lithographic printing plate obtained above is charged by, for example, an ordinary electrophotographic method, and then charged with a xenon lamp, a halogen lamp, a fluorescent lamp, a tungsten lamp, a semiconductor laser, an Ar
After an electrostatic latent image is obtained by exposure to + or He-Ne laser light, toner development is performed.

In the method (1) or (2) described above, the support according to the present invention is used as the support, and after the toner development,
The non-image area (
A lithographic printing plate can be obtained by subjecting the toner-free portions to hydrophilic treatment or by dissolving and removing them using an appropriate solvent.

In the above-mentioned method (3), it is not essential to use the support according to the present invention as the support, and various conventionally known supports for photoconductive layers can be used. Thereafter, the toner image is transferred onto the polymer layer previously provided on the support according to the present invention, heat-fixed, and then the polymer layer in the non-image area is removed to obtain a lithographic printing plate.

Toner development methods include a developer in which both the toner and carrier are solid, a wet method in which the toner or carrier is a liquid, and an aerosol development method in which an air stream is used as a carrier regardless of whether the toner is solid or liquid. be.

The toner used in the present invention is preferably hydrophobic and ink receptive, and toners of either positive or negative polarity can be used.

Furthermore, when the above photosensitive planographic printing plate is used, two types of planographic printing plates, positive and negative, can be obtained with one type of toner developer by utilizing positive and negative polarity charging.

〔Example〕

EXAMPLES Hereinafter, the present invention will be illustrated by giving Examples, but the embodiments of the present invention are not limited thereby.

Example 1 A flat surface of a steel plate with a thickness of 0 and 1511II was roughened by etching with a Baume 40' ferric chloride solution, and a sulfate bath was used for this, at a temperature of 50° C. and a current density of 5 A/dm'.
After 4μ of Zn was competitively plated under the following conditions, parent wood treatment was performed and 20g/12. Phosphoric acid 10
2 A/di with a steel plate as a cathode in a solution containing g/+2
Electrolysis was carried out for 30 seconds at a current density of 30 seconds, followed by washing with water and drying to obtain Support-1.

Production and printing test of lithographic printing plate sample-1 On the support-1 obtained above, the following composition was dispersed and homogenized in a ball mill at room temperature for 48 hours, and then coated to a film thickness of 5 μm. did.

Composition: 1 part by weight of zinc oxide, 2 parts by weight of m-cresol novolak resin, 0.01 parts by weight of rose bengal, 1 part by weight or more of methyl ethyl ketone. Using a reflective positive on the original and a 20W% IO fluorescent lamp as the light source, image exposure was performed through a lens system to obtain an electrostatic latent image, and then a magnetic brush method was used with polystyrene toner.
Performed toner development. The toner image thus obtained is heated and fixed; after that, it is immersed in an alkaline aqueous solution consisting of sodium silicate and caustic potash, and the photoconductive layer in the non-image area (the area to which toner is not attached) is was dissolved and removed to produce lithographic printing plate sample-1.

Next, this printing plate sample was set in an offset printing machine (Nona Sprint L-25B), and printed using coated paper and Nini Bright G Red (manufactured by Toyo Ink Manufacturing Co., Ltd.) as the printing ink. When we observed the dark part of the halftone image of the lithographic printing plate sample-■ and the printed matter with a 25x magnifying glass, we found that
The dot area ratio of 97% was perfectly reproduced.

Example 2 The surface of a rolled steel foil with a thickness of 0-09n+m was plated with 5μm of Fe to give a surface roughness of 0.4μm, and further using a Sargent bath, the temperature was 45°C and the current density was 40A/d+a.
Cr plating with a thickness of 0.1 ttm was performed under the following conditions, and as a hydrophilic treatment, alumina sol (Alumina Sol-200, 8 manufactured by Sankagaku) with a particle size of 50 N++, 30 g IQ, chromic acid 5
Support-2 is immersed in an aqueous solution containing g/Q and dried.
I got it.

Preparation and printing test of lithographic printing plate sample 2 The following composition was coated and dried to a film thickness of 5 μm on the support 2 obtained above to obtain a photosensitive lithographic printing plate.

Composition 2.5-bis-[4'-diethylaminophenyl (1'
))-1,3,4-oxadiazole 10
Parts by weight Styrene-maleic anhydride copolymer 10 parts by weight Rhodamine B O, 5 parts by weight Ethylene glycol monoethyl ether 40 parts by weight This photosensitive lithographic printing plate was treated in the same manner as in Example 1, and lithographic printing plate sample-2 When a sample was manufactured, printed in the same manner as in Example 1, and observed, it was found that the halftone dot area ratio of 97% was completely reproduced.

Example 3 Fabrication and printing test of lithographic printing plate sample-3 The following composition was dispersed for 5 minutes using an ultrasonic disperser at room temperature.
A photosensitive lithographic printing plate was prepared in the same manner as above and treated in the same manner to produce lithographic printing plate sample-3.

Composition ε-type phthalocyanine 1 part by weight m-cresol phenol novolac resin 6 parts by weight ethylene glycol monoethyl ether 24 parts by weight Then, using this lithographic printing plate sample, printing was carried out in the same manner as in Example 1, and observation was made. A point area ratio of 97% was perfectly reproduced.

Example 4 Preparation and printing test of lithographic printing sample-4 The photosensitive lithographic printing plate obtained in Example 3 was positively charged with a corona charging device, and then exposed using a He-Ne laser. After that, ○ was developed using a liquid developer. Then, Example 1
A lithographic printing plate sample-4 was produced by performing the same geography. When printing was performed, the same results as in Example 1 were obtained.

Comparative Example 1 In the production of Support-1 in Example 1, as a hydrophilic treatment, it was immersed in an aqueous solution of carboxymethylcellulose sodium salt and calcium acetate (0.07% by weight each) at room temperature for about 1 minute, washed with water, and dried. Support 3 was obtained in the same manner as in Example 1 except that.

Preparation of lithographic printing plate sample-5 and printing test A lithographic plate was prepared in exactly the same manner as in Example 1, except that support 3 obtained as described above was used in the preparation of lithographic printing plate sample-1 of Example 1. Printing plate sample-5 was produced. When printing was carried out in the same manner as in Example 1 and observed in the same manner, the dot area ratio was 9.
7% were not reproduced.

Comparative Example 2 In the production of Support 2 in Example 2, as a hydrophilic treatment, a 4% by weight potassium permanganate aqueous solution was heated at 40°C.
Support-4 was obtained in the same manner as in Example 2 except that the support was immersed for 1 minute, washed with water, and dried.

Preparation of lithographic printing plate sample-6 and printing test A lithographic plate was prepared in exactly the same manner as in Example 2, except that support 4 obtained as described above was used in the preparation of lithographic printing plate sample-2 of Example 2. Printing plate sample-6 was produced. Next, printing was carried out in the same manner as in Example 1, and observation was made in the same manner. As a result, the halftone dot area ratio of 97% was not reproduced.

Comparative Example 3 Support-5 was prepared in the same manner as in Example 1, except that no post-treatment was performed in the production of Support-1 in Example 1.
I got it.

Preparation of lithographic printing plate sample-7 and printing test Processed in exactly the same manner as in Example 1 except that support 5 obtained as described above was used in the preparation of lithographic printing plate sample-1 of Example 1. A lithographic printing plate sample-7 was prepared and printed under the same printing conditions. When observed in the same manner as in Example 1, the dot area ratio of 97% was not reproduced.

〔Effect of the invention〕

The photosensitive lithographic printing plate of the present invention has good developability and provides printed matter with good image reproducibility.

Claims (1)

[Claims] 1. A photosensitive planographic printing plate prepared by electrophotography, characterized in that the support of the photosensitive planographic printing plate is a support whose surface is treated with a sol of a metal compound.