JPS5944060A - Lithographic plate - Google Patents

Abstract

PURPOSE:To obtain a lithographic plate superior in resolution suitable for liquid development, and in printing resistance even after long term storage, by using a printing plate material prepared by forming a layer contg. at least 2 kinds of photoconductive pyrazoline compds. on a conductive substrate. CONSTITUTION:The printing plate material prepd. by forming a layer contg. at least 2 kinds of photoconductive pyrazoline compds. having formula I on a conductive substrate is imagewise exposed and developed to form a toner image, and fixed by the electrophotographic process, and the nonimage parts are removed by the etching method to obtain a lithographic plate. In formula I , R1, R2, R3 may each be same or different, and each is optionally substd. aromatic, alkyl, aralkyl, -(CH=CH)n-Ar, alkoxy, or heterocyclic; Ar is optionally substd. aryl; and n is 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves forming a toner image on a printing original plate having an organic photoconductive compound layer by an electrophotographic method and fixing it, and then fixing the non-image area other than the toner image forming area with an alkaline aqueous esotyinda solution. This invention relates to a lithographic printing plate obtained by removing etching.

The above-mentioned printing plates using organic photoconductive compounds are already known, for example, Japanese Patent Publication Nos. 37-17162 and 38-69.
No. 61, No. 41-2426, No. 46-39405,
JP-A-50-19509, JP-A No. 50-1.9510,
No. 54-1.45588, No. 50-89801, No. 54-184632, No. 54, -19803, No. 5
5-10524.4, Japanese Patent Application No. 56-48150, and Japanese Patent Application Laid-Open No. 56-146145. These printing plates contain styrene maleic anhydride copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-maleic anhydride copolymer, phenolic resin, and acid value soluble in alkaline aqueous solution as binders. A photoreceptor, that is, a printing original plate, is made by coating an acrylic or methacrylic resin, etc., with an organic solvent and an organic photoconductive compound on a conductive metal substrate such as an aluminum plate, and the electrophotographic method is used to corona charge, expose, and toner. Development and fixing are performed to obtain a toner image on the original printing plate.

Furthermore, by using the toner image as a resist layer and removing the non-image area other than the toner image by etching with an alkaline aqueous etching liquid, the hydrophilic metal substrate is exposed in the non-image area.
A lithographic printing plate is produced in which the toner image area is ink receptive. This method has been put into practical use by Kaare under the trade name IHfasol.

The method using dry toner is inferior in terms of resolution.

It is well known that a method using liquid toner is advantageous in order to obtain high resolution. However, methods using liquid toner cannot provide sufficiently high resolution unless etching removal is easier. Moreover, while it must be easy to remove with an etching solution, it must also have sufficiently high printing durability.

Resolution and printing durability largely depend on the type of binder and toner, but also on the type of photoconductive compound used in a relatively large amount relative to the binder.

Various compounds are known as photoconductive compounds. Among these, pyrazoline compounds are preferable as compounds exhibiting good electrophotographic properties.

However, when used in lithographic printing plates, it cannot be said to be sufficient in terms of resolution and printing durability, and especially when lithographic printing plates are stored for a long period of time, the resolution and printing durability sometimes decrease. It has the disadvantage of

An object of the present invention is to provide a lithographic printing plate suitable for liquid development that solves these drawbacks.

The object of the present invention is to form a toner image on a printing original plate having a layer containing an organic photoconductive compound on a conductive substrate by an all-electrophotographic method, and after fixing, remove the non-image area by etching. , the above-mentioned 4-dimensionally conductive compound and 2-C have at least two kinds of compounds represented by the following general formula! One on the lithographic printing plate with the symbol “i”-C
Achieved J'1. Nnnn two.

General formula (wherein, IL+, 112 and loss may be different or the same, respectively, an aromatic group which may have a substituent, an alkyl group, an aralkyl group, -(-Oll-=
011→7. Represents an Ar- group, an alkoxy group, or an atom ring group. Ar represents an aryl group which may have a substituent, and n represents 1 or 2. ) The pyrazoline compound represented by the above general formula has ie7. Preferably, the compound has at least one aryl group having a substituent and optionally containing -C, or HAr group represented by 〇H in -〇〇). Examples of groups that can be substituted for these aryl groups include &2L, an alkyl group, a dialkylamino group, an alkoxy group, a hydroxyl group, and a halogen atom.

At least two of the compounds represented by the general formula 1 are used in combination. A particularly useful combination is one in which all of the IL+-ILs of the above general formula are selected from aryl groups, (- Off = Orl salt Ar groups, and the total number of carbon atoms of the substituents of these aryl groups is 8 or more. The combination of at least one certain pyrazoline compound and at least one other pyrazoline compound is 1%.The combination ratio is:
Lithographic printing that can be varied within any range depending on the type of compound, type of binder, desired properties, etc., and has higher resolution and printing durability even during storage than lithographic printing plates that use each separately. You can get the version.

Said general formula! Representative examples of the represented compounds are shown below.

However, only l'L1 to Rj are shown.

Me represents a methyl group, and Et represents an ethyl group.

These compounds themselves are known and can be easily synthesized by those skilled in the art.

The base material used in the present invention can be used without any restriction as long as it has conductivity and hydrophilicity. For example, aluminum, plate,
Examples include zinc plates, gold B4 plates such as needle plates, aluminum foils, aluminum vapor-deposited films, etc., but photoconductive compounds and ζingo are removed by etching treatment,
Since the non-image area must have hydrophilic properties, the base material having a hydrophobic surface must be subjected to a hydrophilic treatment in advance. A metal plate, particularly an aluminum plate, is most suitable, but it is preferable that the surface has been subjected to a hydrophilic treatment such as graining treatment, alkali treatment, acid treatment, or anodization. In particular, the advantages of the present invention are significantly exhibited in substrates that have been treated to be hydrophilic with phosphoric acid or a salt thereof, or an alkali metal silicate.

To produce a printing original plate, at least two of the photoconductive compounds of the present invention and a ζ inder are dissolved in a solvent;
A sensitizing dye is added and coated onto the support to a thickness of 1 to 30 μm and dried. The ratio of the photoconductive compound to the binder is 0.01 to 50 parts by weight of the binder to 1 part by weight of the total photoconductive compound, preferably 0.2 to IO parts by weight, although it varies depending on the photoconductive compound used. A range of is appropriate.

Those that can be used as solvents include all organic solvents that are capable of dissolving the binder and dissolving or dispersing the photoconductive compound.

For example, alcohols such as methanol, ethanol, alcohol, phthanol, and hexyl alcohol, cellosols such as methyl cellosolve, ethyl cellosolve, and methyl cellosolve, aromatics such as benzene, toluene, and xylene, and dioxane and tetrahydrofuran. Examples include cyclic ethers, esters such as ethinoacetate, butinoacetate, and amyl acetate, ketones such as acetone, methyl in butyl ketone, and methyl ethyl ketone, dimethyl formamide, dimethyl sulfoxide, and halogenated hydrocarbons. For safety reasons, two or more solvents are often used in combination.

As the Nono Ingu, any of the known Nono Ingoes mentioned above can be used as long as it can be etched with an alkaline solution.

The lithographic printing plate of the present invention is particularly useful in a laminated structure in which the birazoline compound cloth layer having the general formula described above is used as a charge carrier transfer layer, and a charge carrier generation layer is provided below the layer. The charge carrier generation layer preferably contains the polyamide resin described in Japanese Patent Application No. 57-1.321. As the charge carrier generation material, various types known as organic photoconductors can be used. There are various types of dyes known as organic pigments and sensitizers. Examples of organic pigments include metal-free and metal-containing phthalocyanine pigments, monoazo and disazo pigments, quinacridone pigments, pinzimiguzole pigments, indigo pigments, polycyclic quinone pigments, beclene pigments, quinoline pigments, cyanine pigments f"l, and biryllium salt pigments. Examples of dyes include triphenylmethane dyes such as methyl violet, crystal violet, ethyl violet, and Victoria blue; thiazine dyes such as methylene blue; quinone dyes such as quinizarin; and xanthene dyes such as rhodamine B.
Cyanine dye, pyrylium salt, thiapyrylium salt,
Infection sensitizers such as indigo IJ and IJum salts and JP-A-1983
There are reinforcing charges described in No. 79541.

There is no particular limit to the amount of these charge carrier generating substances added to Singoo, but if the amount is too large, the adhesion will deteriorate, so it is preferably in the range of 5 to 50 weight percent.

The toner used for image formation is preferably a liquid toner.

Examples of the toner include styrene resin, acrylic resin, styrene-acrylic resin, styrene-methacrylic resin, polyester resin, and epoxy resin. ! In practical use, it is preferable to contain pigments and dyes for coloring, as well as a charge control agent, within a range that does not adversely affect the stability and fixing properties of the toner.

The printing original plate of the present invention is obtained by etching the non-image area with an aqueous alkaline solution after forming a toner image by an electrophotographic method. Examples of the alkali include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium phosphate, potassium phosphate, and anhydride. Further, it is more preferable to add alcohol to the present alkaline aqueous etching solution in terms of etching speed. As the alcohol, lower alcohols such as methanol, ethanol, pronominol, butanol, benzyl alcohol, and phenethyl alcohol, aromatic alcohols, and polyethylene glycols such as ethylene glycone, polyethylene glycol, and celonolbu can be used. Etching treatment can be performed using an alkaline aqueous solution alone, but monoethanolamine 1. It is preferable to use amino alcohols such as jetanolamine and triethanolamine, and from the viewpoint of resolution and image reproducibility, a combination of amino alcohols and alcohols is most preferable.

After this etching treatment, washing with water and treatment with a diluted acid water bath exhibits excellent characteristics in terms of background smearing and image reproducibility during printing.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1: On a mechanically grained and anodized aluminum plate with a thickness of 0.8 microns (with the following formulation, a charge carrier generation layer of 08 micron thickness and a charge carrier transfer layer of 5 micron thickness) An electrophotographic laminated photoreceptor is fabricated by sequentially applying layers to obtain a laminated lithographic printing original plate.

<Charge Carrier Generation Layer Coating Solution Prescription> Charge Carrier Transfer Layer Coating Solution> Eight types of lithographic printing original plates were prepared using the above pyrazoline compounds as shown in the table below.

Evaluation of printing durability and resolution was based on the following criteria.

[Printing life test]

]・・・50,000 sheets or more 2・・・・・・80,0. (10-50,000 sheets 8.
...--s o, o o o or less [resolution] Sharpness of halftone dots e a, irλ Examined with a microscope l...
...Very good 2...Fair (standard) 8...Poor The results are shown in Table 1.

After these lithographic printing original plates were left under natural conditions for 8 months, a continuous tone original was printed using a contact screen and a plate making camera. Caps type 41L liquid toner was used as the toner. Next, it was immersed in the following etching solution for 15 seconds to perform etching treatment.

<Etching treatment liquid> After washing the above-mentioned printing plate with water, the non-image area was treated to make it hydrophilic with a dithiphosphoric acid aqueous solution, and a printing durability test was conducted using an AM-1250 offset printing machine.

Example 2 A coating solution having the following formulation was prepared to obtain a laminated lithographic printing original plate having a charge carrier generation layer with a thickness of 0.7 microns and a charge carrier transfer layer with a thickness of 4 microns.

<Charge carrier generation layer coating liquid formulation><Charge carrier transfer layer coating liquid> As the above pyrazoline compound, 7 as shown in the table below
A lithographic printing original plate of glaze was obtained.

Thereafter, the results of tests conducted in the same manner as in Example 1 are shown in Table 2.

Table 2 Example 8 Butyl methacrylate-methacrylic acid (75:25
) 4p and 6 g of styrene-maleic anhydride copolymer Hafestel (monomer composition ratio 60:40) were dissolved in a mixed solvent of 70 g of ethylene glycol monomethyl needle and 80 g of toluene, and in this solution, a pyrazoline compound of the general formula was dissolved. A total of 8 g was dissolved, 5 di of a 1% DMF solution of ethyl violet was added as a sensitizing dye, and the total amount was adjusted to 150 g with ethylene glycol monomethyl ether.

250 treated with hydrophilic treatment using anodizing and sodium silicate
The mixture was coated onto a μ aluminum plate using a wire glue so that it became a solid layer, and was dried to obtain a printing original plate.

Hereinafter, the results of the test conducted in accordance with Example 1 are shown in Table 8.

Looking at any of the examples in Table 8, it can be seen that by combining the general formula pyrazoline, a lithographic printing plate with excellent printing durability and resolution even after storage can be obtained. Procedural Amendment (Spontaneous) 1 , Middle/Table of Matters/Jζ In 1982 I Special Fraud Application No. /j5; fA 5'
7. No. 2, Name of the invention in plain text, 7 words, and 3, Relation to 11 amendments Patent Applicant fI: Location
Chiyo, Tokyo] Marunouchi, H-ku -: 0-chome [No. 14-2 Name (598)-11kura Co., Ltd. 4, Agent Address: Inside Mitsubishi Paper Mills Co., Ltd., 2-4-2 Marunouchi, Chiyoda-ku, Tokyo 100 5. Amendment Order 1-1 A.1 (1) ``No. 50-898.01'' on page 2, line 13 of the specification is changed to ``No. 54-89801 AI, tT Correction (2) No. 7 of the same.
Page NQ, 7. (3) Same page 10, lines 6 to 7 (Corrected "ethyl cellosolve" to r ethyl cellosolve J (4) Same page 10, line 7, "butyl cellosolve J" (5) Corrected “Cellosolve” on page 10, line 7 to “Cellosolve J” (6) Corrected “Vinz r Midazole Pigment” from page 11, line 10 to line 11 of the specification. Corrected to “Nzimidazole Pigment” (7) Same No. 1
On page 1, line 12, “Korilene pigment” was corrected to “Korilene pigment” (8) On page 12, line 13, “pigment, or dye,” was corrected to “pigment or dye, J” 405-

Claims (1)

[Claims] (1) In a printing original plate 'fr having an organic photoconductive compound-containing layer on a conductive substrate, a lithographic printing plate obtained by forming a toner image on the entire toner image by electrophotography, and removing the non-image area by etching after fixing. , at least 2114 compounds represented by the following general formula as the organic photoconductive compound
A lithographic printing plate characterized by containing i. General formula (wherein, ribs, R2 and ILa may be different or the same, and an aromatic group which may have a substituent,
Represents an alkyl group, aralkyl group, (-OH= OH group, alkoxy group, "fM bare ring group. Ar represents an aryl group which may have a substituent, and n represents 1 or 2. show.)