JPS60242473A - Original printing plate for electrophotographic engraving - Google Patents

Abstract

PURPOSE:To obtain an original printing plate having especially high sensitivity and high printing resistance by forming on a conductive substate an electrophotographic sensitive layer composed of two layers of an electrostatic charge generating layer contg. an azo pigment represented by formula I and a charge transfer layer contg. a charge transfer material and an alkali-soluble resin. CONSTITUTION:The charge generating layer 3 and the charge transfer layer 4 are laminated on the conductive substrate 1 to form an electrophotographic sensitive layer 2. The layers 3, 4 may be reversely laminated. The azo pigment coupler is represented by formula I, where (A) is a coupler residue, and said coupler is such as compds. having a phenolic OH, e.g., phenols and naphthols, aromatic amino compds. aminonaphthols having NH2 and phenolic OH, compds. having aliphatic ketones or aromatic phenolic ketones (active methylenes), and said coupler residue (A) is, preferably, selected from a specified group. The charge transfer layer is formed of the charge transfer material and the alkali- soluble resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a novel printing plate that can be made by electrophotography. More specifically, in a new printing plate containing a specific azo pigment, an electrostatic latent image obtained by charging and subsequent imagewise exposure is developed with toner, fixed to obtain a toner image, and then a non-image This invention relates to a printing plate that is made by eluting and removing a photosensitive layer.

BACKGROUND ART Conventionally, as master plates for lithographic printing, those using photosensitive resins or silver halide photosensitive materials have been known.

However, although lithographic printing plates using photosensitive resin have high printing durability, they have low sensitivity, and so-called direct plate making is not possible, and it is necessary to first create a cine or I-ji from a silver halide film from an original. However, there are drawbacks such as the need for large-scale equipment and the time required for plate making.

Further, although printing plates using diffusion transfer development or hardening development methods of silver halide photosensitive materials can be directly plate-made, they have the drawbacks of low printing durability and high cost per sheet.

Examples of printing plates for direct plate making using electrophotography include JP-B No. 47-47610 and JP-B No. 48-40.
002, Special Publication No. 48-18325, Special Publication No. 51-157
No. 66, Japanese Patent Publication No. 51-25761 discloses a zinc oxide-resin dispersion printing plate. After a toner image is formed on this printing plate by electrophotography, it is treated with an acidic aqueous solution containing, for example, a ferrocyanate in order to make the non-image area hydrophilic.

Printing plates made in this way tend to peel off due to the mechanical pressure applied during printing and the penetration of dampening water into the photosensitive layer and conductive layer, destroying the hydrophilic layer on the surface. Its printing durability was approximately 5,000 to 1,000 sheets.

In addition, zinc oxide/resin dispersion printing plates are dye sensitized in order to have sensitivity in the visible light region, but even so, they do not exhibit sensitivity sufficient for practical use in the long wavelength light region of 600 nm or more. Therefore, low-power and inexpensive He-Ne
The disadvantage is that exposure cannot be performed using a laser or semiconductor laser.

On the other hand, Tokuko Sho 37-17162, Tokuko Sho 38-775 &
JP 46-39405, JP 52-2437, JP 56-107246, JP 55-105254,
JP-A-55-153'948, JP-A-55-16125
, JP-A-57-147656, JP-A-56-14614
5. JP-A-57-161863 discloses, for example, a layer consisting of an organic photoconductive compound and an alkali-soluble resin on a hydrophilic conductive support such as a grained aluminum plate, or A printing original plate for electrophotographic engraving is provided with a layer in which a charge-generating pigment such as a phthalocyanine pigment is dispersed in an alkali-soluble resin, or a layer sensitized by adding an electron-withdrawing substance or an electron-donating substance to this dispersed layer. It is shown. This type of printing original plate is made by forming a toner image on the photosensitive layer using an electrophotographic method, and then eluting and removing the photosensitive layer in the non-image area with an alkaline solution. Although it has the advantage that a printing plate can be obtained, it has low sensitivity as a photoreceptor for electrophotography, resulting in a slow plate-making speed and the disadvantage that a high-output light source must be used.

Purpose An object of the present invention is to solve the problems of the conventionally known printing original plates for electrophotographic engraving as described above, and to provide a printing original plate having particularly high sensitivity and high printing durability.

Structure The printing original plate for electrophotolithography of the present invention comprises a charge generation layer containing an azo pigment represented by the following general formula (I) and a charge transport layer containing a charge transport substance and an alkali-soluble resin on a conductive support. It is characterized by being provided with an electrophotographic photosensitive layer consisting of two layers.

General formula (1) (However, A represents a Cassiller residue.) The basic structure of the printing original plate for electrophotographic engraving of the present invention is shown in FIG.

Here, 1 is a conductive support, on which a charge generation layer 3 and a charge transport layer 4 are laminated, and an electrophotographic photosensitive layer 2
is formed.

The charge generation layer 3 and the charge transport layer 4 can also be stacked upside down.

Couplers for the azo pigment used in the charge generation layer 3 include:
For example, compounds with a phenolic hydroxyl group such as phenols and naphthols, aromatic amine compounds with an amine group, aminonaphthols with an amine group and a phenolic hydroxyl group, or aliphatic or aromatic enolic ketone groups (active methylene group). ) is used,
Preferably, the coupler residue A has the following general formula (II), (
I[I], (IV), (V), (Vl), (■).

[Wherein, R1 is hydrogen, an alkyl group, a phenyl group, or a substituent thereof; X is a hydrocarbon ring or a substituent thereof; a heterocycle or a substituent thereof; Y is a hydrocarbon ring group or a substituent thereof; cyclic group or substituted product thereof or -
N=CH R2 (wherein, R23 is a hydrocarbon ring group or a substituent thereof, a heterocyclic group or a substituent thereof, or a styryl group or a substituent thereof, R3 is hydrogen, an alkyl group, a phenyl group, or a substituent thereof (Alternatively, R2 and R3 may form a ring together with the carbon atom to which they are bonded.)] (R4 in formulas (I[I) and (IV) is a substituted or unsubstituted carbon (Represents a hydrogen group.) Ar1 (In the formula, R5 represents an alkyl group, a carbamoyl group, a carboxyl group, or an ester thereof, and Ar1 represents a hydrocarbon ring group or a substituted product thereof.) 1"ITJ (In the formula, R6 is a hydrocarbon group or a substituted product thereof, A
r 2 represents a hydrocarbon ring group or a substituted product thereof.

) The hydrocarbon ring for X in the general formula used in the present invention includes a benzene ring, a naphthalene ring, etc.
Examples of the heterocycle include an indo-2 ring, a carbazole ring, and a benzofuran ring. Examples of the hydrocarbon ring group for Y or R2 include a phenyl group, a naphthyl group, an anthryl group, and a pyrenyl group. Examples of the heterocyclic group include a pyridyl group. , chenyl group, furyl group, indolyl group, benzofuranyl group, carbazolyl group, dipenzofuranyl group, etc., and R2
Examples of the ring that R3 can form together with the carbon atoms to which they are bonded include a fluorene ring.

Furthermore, examples of the hydrocarbon group in R4t or R6 include alkyl groups such as methyl, ethyl, propyl, and butyl, aralkyl groups such as benzyl, aryl groups such as phenyl, and substituted products thereof. R4
Alternatively, substituents on the hydrocarbon group of R6 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, chlorine atom, bromine atom, etc. Examples include halogen atoms, hydroxyl groups, and nitro groups. Examples of substituents on the phenyl group of R1 or the ring of X include halogen atoms such as chlorine atoms and bromine atoms, and Y or R
Examples of substituents on the carbocyclic group or heterocyclic group of 2 or the ring formed by R2 and R6 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group,
Alkoxy groups such as methoxy, ethoxy, propoxy and butoxy groups; halogen atoms such as chlorine and bromine; dialkylamino groups such as dimethylamino and diethylamino groups; dialkylamino groups such as dibenzylamino groups; Examples include halomethyl groups such as trifluoromethyl groups, nitro groups, cyan groups, carboxyl groups or esters thereof, hydroxyl groups, and sulfonic acid groups (-so3Na). Furthermore, as the hydrocarbon ring group in Ar1 or Ar2, phenyl group, naphthyl group, etc.
Substituents for these groups include alkyl groups such as methyl, ethyl, propyl, butyl, alkoxy groups such as methoxy, ethoxy, zoropoxy, and butoxy, nitro, chlorine, and bromine. Examples thereof include norogen atoms such as, dialkylamino groups such as cyano group, dimethylamino group, and diethylamino group.

The azo pigment used in the present invention is, for example,
103996 and Japanese Patent Application No. 58-011148. Examples of these azo pigments are as follows.

(12) The charge generation layer 3 is a layer mainly composed of an azo pigment represented by the general formula (I), but may contain a binder if necessary. In this case, the proportion of azo pigment in the charge generating layer is preferably 30% by weight or more. Since the printing original plate of the present invention elutes the non-image area during the plate-making process, when using a binder, for example, an alkali-soluble resin such as a styrene-maleic anhydride copolymer or a novolak type phenolic resin (after ) is preferably used. However, if the proportion of the binder is small, it is also possible to use other resins. Further, the thickness of the charge generation layer 3 is preferably 0.01 to 5μ, more preferably 0.00μ.
05~2 fish. If the thickness is less than 0.01 μm, charge generation will not be sufficient, and if it is more than 5 μm, the residual potential will be too high for practical use.

The charge transport layer 4 is formed of a charge transport substance and an alkali-soluble resin. Charge transport substances include hole transport substances and electron transport substances, and hole transport substances include, for example, 2
,5-bis(4-diethylaminophenyl)-1,3,
4-oxadiazole, 2,5-bis[4-(4-S'
[Dimethylaminostyryl)phenyl]-,1,3,4-
Oxadiazole, 2-(9-ethylcarbasolyl-3)
-)-s-(4-diethylaminophenyl)-1,3,
oxadiazole compounds such as 4-oxadiazole;
2-vinyl-4-(2-chlorophenyl)-5-(4-
diethylamino)oxazole, oxazole compound of 2-(4-diethylaminophenyl)-4-phenyloxazole, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)
Pyrazoline, pyrazoline compounds such as 1-phenyl-3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline, 2,2'-dimethyl-
Diphenylmethane compounds such as 4,4'-bis(diethylamino)triphenylmethane, 1,1-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 9-(4-dimethylaminobenzylidene) Fluorene, fluorene compound of 3-(9-fluorenonedene)-9-ethylcarbazole, 9-(4-diethylaminostyryl)anthracene, 9-bromo-10-(4-diethylaminostyryl)
Styryl anthracene compounds such as anthracene, 1,
2-bis(4-diethylaminostyryl)benzene, 1
, 2-bis(2,4-dimethoxystyryl)benzene and other distyrylbenzene compounds, 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1 -Phenylhydrazone, 4-diethylaminobenzaldehyde 1,1-diphenylhydrazone, 2,4
-Hydrazone compounds such as dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diphenylaminobenzaldehyde 1-methyl-1-phenylhydrazone, 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, etc. Styrylnaphthalene compounds such as 1-(4-diphenylaminostyryl)naphthalene, 1-(4-dibenzylaminostyryl)naphthalene, 4'-diphenylamino-α-phenylstilbene,
α-phenylstilbene compounds such as 41-methylphenylamino-α-phenylstilbene, 3-styryl-
9-ethylcarbazole, 3-(4-diethylamino)
Styrylcarnogzole compounds such as styryl-9-ethylcarbazole are used.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-dolinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4.5.7-Titranitroxanthone, 2.4.8
- Trinidrothioxanthone, 2,6,8-trinitro-4H-indenoC1,2-b')thiophene-4-
1,3,7-dolinitrodibenzothiophene-5
, 5-dioxide, etc.

The alkali-soluble resin used in the charge transport layer 4 refers to a resin that becomes soluble in an aqueous or alcoholic solvent by adding an alkali. For the purposes of the present invention, in addition to properties such as film-forming properties, electrical properties, and adhesion strength to a support, solubility properties are particularly important for these resins. Examples of resins having such a height characteristic include styrene-maleic anhydride copolymers, styrene-methacrylic acid-methacrylate copolymers, methacrylic acid-methacrylate copolymers, and phenol resins.

Examples of phenolic resins include phenol, 0-cresol, m-cresol, p-cresol, ethylphenol, isopropylphenol, t-butylphenol, and t-cresol.
-amylphenol, hexylphenol, L-octylphenol, cyclohexylphenol, 3-methyl-4-10-6-t-butylphenol, isopropylcresol, t-butylcresol, amylcresol, hexylcresol, L-octylcresol and cyclohexyl A noblack type resin is used which is obtained by condensing at least one substituted phenol such as cresol with an aldehyde such as formaldehyde, acetaldehyde, acrolein, crotonaldehyde, or furfural under acidic conditions.

The charge transport layer 4 is a layer mainly composed of a charge transport substance and an alkali-soluble resin, and the ratio of the charge transport substance in the layer is 10 to 10.
70% by weight, preferably 20-60% by weight. When the proportion of the charge transport substance is below this range, almost no charge is transported, and when it is above this range, the mechanical strength of the layer is so poor that it cannot be put to practical use. Further, the thickness of the charge transport layer 4 is 2 to 50 μm, preferably 3 to 20 μm. Below this range, the amount of charge will be insufficient, and above this range, the residual potential will be high and the elution of the layer will take time, which is not practical.

The charge transport layer 4 may preferably contain a plasticizer.

Effective plasticizers include, for example, phthalic acid esters such as dimethyl phthalate, diethyl phthalate, and dibutyl phthalate, and glycol esters such as dimethyl glycol phthalate and ethyl phthalyl ethyl glycolate.

These plasticizers can be contained within a range that does not deteriorate the electrostatic properties and alkali solubility of the photoconductive layer.

The conductive support 1 used in the present invention is an aluminum plate, a zinc plate, a bimetal plate such as a copper-aluminum plate, a copper-stainless steel plate, a chrome-copper plate, or a chromium-copper-aluminum plate, a chromium-lead-iron plate. , chromium-
A conductive support with a hydrophilic surface such as a tri-metal plate such as a copper-stainless steel plate is used, and its thickness is 0.1
~1 kaku is preferred.

In addition, especially in the case of a support having an aluminum surface, surface treatments such as graining, dipping in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate, etc., or anodizing are performed. Preferably. Furthermore, as shown in U.S. Pat.
It is also preferable to carry out an anodic oxidation treatment and then immersion treatment in an aqueous solution of an alkali metal silicate as shown in Japanese Patent No. 5125.

The above anodizing treatment is performed by using an aluminum plate as an anode in an electrolytic solution consisting of a solution of an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid, or boric acid, or an organic acid such as oxalic acid, sulfamic acid, or a salt thereof. It is carried out by passing an electric current.

To produce the printing plate for electrophotographic engraving of the present invention, first, the pigment represented by the general formula (1) and a binder, if necessary, are mixed with, for example, tetrahydrofuran, dioxane, dimethylformamide, acetone methyl ethyl ketone, ethylene glycol monomethyl ether, etc. , ethylene glycol monoethyl ether, ethyl acetate, butyl acetate, toluene, halogenated hydrocarbon, etc., and uniformly dispersed using a dispersing means such as a sol mill or an ultrasonic disperser. The charge generation layer 3 is provided by coating on a conductive support and drying. Next, a solution in which a charge transport substance and an alkali-soluble resin are dissolved in the same organic solvent as above is applied onto the charge generation layer and dried to form the charge transport layer 4.

The plate making of the original printing plate for electrophotographic platemaking of the present invention is performed by first uniformly charging it in a dark place using a corona charger or the like, using a tungsten lamp, halogen lamp, etc., according to the usual electrophotographic method.
Electrostatic latent images are created by reflective image exposure using a light source such as a xenon lamp or fluorescent lamp, contact image exposure through a transparent positive film, or scanning exposure using laser light such as a He-Ne laser, argon laser, or semiconductor laser. This electrostatic latent image is developed with toner and fixed by heating to obtain a toner image on the electrophotographic photosensitive layer (FIG. 2).

Next, when the printing plate on which the toner image has been formed in this way is immersed in an alkaline eluent, the electrophotographic photosensitive layer (charge generation layer and charge transport layer) in the non-image area that is not covered by the toner image is removed. The hydrophilic surface of the conductive support is exposed by dissolution, leaving only the toner image area, and a good printing plate can be obtained (FIG. 3).

The eluent used here is, for example, an alkaline aqueous solution of an inorganic salt such as sodium silicate, sodium phosphate, sodium hydroxide, or sodium carbonate, an alkaline aqueous solution containing organic amines such as triethanolamine or ethylenediamine, or an alkaline aqueous solution containing organic amines such as triethanolamine or benzyl alcohol. , a solution containing an organic solvent such as ethylene glycol or glycerin or a surfactant is used.

In the printing plate of the present invention, after the toner image is formed, the non-image area is dissolved and removed in the eluent, so the toner components include:
It is preferable that this eluate contains a resin component having resist properties.

This resin component may be anything that is insoluble in the eluate, such as acrylic resin using methacrylic acid, methacrylic acid ester, vinyl acetate resin, copolymer of vinyl acetate and ethylene or vinyl chloride, etc. , vinyl chloride resin, vinylidene chloride resin, vinyl acetal resin such as polyvinyl butyral, polystyrene, copolymers of styrene and butadiene, methacrylic acid ester, etc., polyethylene, polypropylene and their chlorides,
Examples include polycarbanates, polyester resins, polyamide resins, phenolic resins, xylene resins, alkyd resins, waxes, polyolefins, and waxes.

The printing original plate of the present invention may also contain a quinonediazide compound such as 0-naphthoquinonediazide or a diazo compound for the purpose of increasing the solubility of the shimiko photosensitive layer upon full-surface exposure after toner image formation.

In the printing original plate of the present invention, after the plate-making process is completed, the conductive substrate with a hydrophilic surface is exposed in the non-image area, and the image area covered with oleophilic toner remains. The ink adheres only to the image area, resulting in good printed matter without scumming.

In addition, the printing original plate of the present invention has the following characteristics compared to conventional printing original plates:
In particular, the sensitivity is high, and direct plate making is possible with various light sources such as He-Ne lasers and semiconductor lasers, and the printing plates obtained thereby have high printing durability.

Next, the present invention will be explained in more detail using examples.

In addition, all "parts" in the examples represent parts by weight.

Example 1 1 part of azo pigment A1, 0 part of m-cresol-phenol copolymerized novolak resin (manufactured by Gunei Chemical Co., Ltd.: MP-707)
．． 667 parts of 74 wt% tetrahydrofuran solution was added to yN
- Grind and mix the resulting dispersion in a Lumir to a thickness of about 0.2
It was coated on a 5wm grained aluminum plate and dried at 80°C for 10 minutes to form a charge generation layer with a thickness of about INrL.

2,5-bis(
4-diethylaminophenyl) -1,3,4-, txadiazole 0.9 parts, 1.8 parts of styrene-maleic anhydride copolymer (copolymerization molar ratio 1:1, manufactured by Aldrich Chemical Kannozoni) and A solution prepared by mixing and dissolving 13.2 parts of tetrahydrofuran was applied and dried at 80° C. for 20 minutes to form a charge transport layer with a thickness of about 10 μm. ! A printing master plate for the plate was created.

This original printing plate was tested using an electrostatic copying paper tester (newly manufactured by Kawaguchi Denki Co., Ltd.: Model 5P-428).
After corona discharge of V was performed for 20 seconds to make it negatively charged, the surface potential was determined by leaving it in a dark place for 10 seconds. (Volts), then irradiate the surface with light using a tungsten lamp at an illuminance of 4.5 lux, measure the time it takes for the surface potential to reach voQμ, and measure the half-life exposure amount E1/2 ( lux seconds) was calculated. The results are shown in Table 1.Next, this printing original plate was applied to an electronic copy plate making machine (Ricoh S-1).
A clear toner image was formed on the charge transport layer by charging, imagewise exposure, development and fixing.

This original plate was treated with 70 g of sodium metasilicate and grise.

It was immersed for 1 minute in a solution of 550 ml of phosphorus 140+n11 ethylene glycol and 150 m/+ ethanol, and then washed with a light stream of water to remove the electrophotographic photosensitive layer in the non-image areas to which toner was not attached.

The printing plate made in this way is then printed on an offset printing machine (
AP-1310 model manufactured by Ricoh Co., Ltd.) and printed using a conventional method, it was possible to print more than 50,000 clear prints.

Examples 2 and 3 Electrophotographic printing of the present invention was carried out in the same manner as in Example 1, except that the compounds shown in Table 1 were used as the azo pigment used in the charge generation layer and the charge transport substance used in the charge transport layer, respectively. An original plate was prepared, and vO and E1/2 were measured.

The above results are shown in Table-1.

(Left below) Example 4 1 part of Azo Pigment 516, 0% of m-cresol-phenol copolymer Noblack resin (manufactured by Gunei Chemical Co., Ltd.: MP-707)
．． 66.7 parts of a 74 wt% tetrahydrofuran solution was pulverized and mixed in a ball mill, and the resulting dispersion was mixed to a thickness of about 0.5 wt%.
It was coated on a 25 m+ grained aluminum plate and dried at 80° C. for 10 minutes to form a charge generating layer about 1 cotton thick.

3-styryl- as a charge transport substance on this charge generation layer.
1.5 parts of 9-ethylcarbazole, m-cresol-phenol copolymerized novolac resin (manufactured by Gunei Chemical: MP-
707) 3.0 parts and 12.0 parts of tetrahydrofuran
A solution obtained by mixing and dissolving the following parts is applied, followed by drying at 80° C. for 2 minutes and then at 100° C. for 10 minutes to form a charge transport layer with a thickness of about 101 I/rrL. It was created. Regarding this printing original plate, Vo and E1/2 were measured in the same manner as in Example 1, and the results are shown in Table 2.

Next, a toner image was formed on the electrophotographic photosensitive layer of this printing original plate in the same manner as in Example 1, and then immersed for about 45 seconds in a solution consisting of 2.5 parts of sodium metasilicate and 100 parts of water. The electrophotographic photosensitive layer in the non-image area was removed by washing while lightly brushing with water.

When the printing plate made in this manner was printed on an offset printing machine, more than 5,000 clear prints could be printed.

Examples 5 to 8 Printing for electrophotographic printing of the present invention was carried out in the same manner as in Example 4, except that the compounds shown in Table 2 were used as the azo pigment used in the charge generation layer and the charge transport substance used in the charge transport layer, respectively. Create the original version, v.

and E1/2 were measured.

The above results are shown in Table-2.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic structure of the printing original plate for electrophotographic engraving of the present invention. Figures 2 and 3 are diagrams explaining the plate-making process of the printing original plate of the present invention, Figure 2 shows a state in which a toner image has been formed, and Figure 3 shows a state in which a non-image area has been eluted and removed. show. 1... Conductive support, 2... Electrophotographic photosensitive layer, 3...
... Charge generation layer, 4... Charge transport layer, 5... Toner image. Patent applicant Rico Co., Ltd. - Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] An electronic device consisting of two layers, a charge generation layer containing an azo pigment represented by the following general formula (I) and a charge transport layer containing a charge transport substance and an alkali-soluble resin, on a conductive support. A printing original plate for electrophotographic engraving, characterized by being provided with a photosensitive layer. General formula (1) (However, the person in the formula represents all Cassilla residues.)'