JPS60242471A - Original printing plate for electrophotographic engraving - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 and fixed to obtain a toner image. The present invention relates to a printing plate that is made by dissolving and removing a photosensitive layer in a non-image area.

BACKGROUND ART Hitherto, as lithographic printing original plates, 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 cannot be used in so-called direct plate making, requiring the operation of first creating negatives or positives from originals using silver halide film. 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 plate.

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. 1973-18'3-25, Special Publication No. 51-1
5766 and Japanese Patent Publication No. 51-25761, printing plates having a zinc oxide-resin dispersion system are known. After forming a toner image on this printing plate by electrophotography, it is treated with, for example, an acidic aqueous solution containing ferrocyanate in order to make the non-image area hydrophilic. Printing plates made in this way 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. Printing durability is 5.000-
It was about 10,000 schools.

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-N
It has the disadvantage that it cannot be exposed using an e-laser or a semiconductor laser.

On the other hand, Japanese Patent Publication No. 37-17162, Special Publication No. 38-7758
, JP 46-39405, JP 52-2437, JP 56-107246, JP 55-10525'4
, JP-A-55-153948, 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 layer consisting of a phthalocyanine. A layer in which charge-generating pigments such as pigments are dispersed in alkali-soluble resin,
Alternatively, a printing original plate for electrophotographic engraving is disclosed in which a layer sensitized by adding an electron-withdrawing substance or an electron-donating substance to the dispersion layer is provided. 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 the disadvantage that it has low sensitivity as a photoreceptor for electrophotography, resulting in slow plate-making speed and the need to use a high-output light source.

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 (1) 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 coupler 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 amino compounds with an amino group, aminonaphthols with an amino group and a phenolic hydroxyl group, or aliphatic or aromatic enolic ketone groups (active methylene group). ) is used,
Preferably, the hakaffler residue A is represented by the following general formula (■), aI
D, (I11/).

(V), CVD, and the group represented by ■.

[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; The ring group or its R2 is a hydrocarbon ring group,
or substituents thereof, heterocyclic groups or substituents thereof,
or a styryl group or a substituent thereof, R5 represents hydrogen, an alkyl group, a phenyl group, or a substituent thereof;
Alternatively, R and R3 may form a ring with the carbon atom to which they are attached. ]] (R4 in the formula (to) and (I) represents a substituted or unsubstituted hydrocarbon group.) r 1 (In the formula, R5 is an alkyl group, carmoyl group, carboxyl group, or its represents an ester, and Ar represents a hydrocarbon ring group or a substituted product thereof.) 60 (wherein, R6 is a hydrocarbon group or a substituted product thereof, A
r 2 represents a hydrocarbon ring group or a substituted product thereof.

) Examples of the hydrocarbon ring for X in the general formula used in the present invention include a benzene ring and a naphthalene ring; examples of the heterocycle include an indole ring, a carbazole ring,
Examples of the hydrocarbon ring group in R2, such as benzofuran rings, include phenyl group, naphthyl group, anthryl group,
Examples of heterocyclic groups such as gyrenyl group include pyridyl group, chenyl group, furyl group, indolyl group, benzofuranyl group,
Carbazolyl group, dibenzofuranyl group, etc., and R2 and R3 are formed together with the carbon atoms to which they are bonded.

Examples of possible rings include fluorene rings.

Furthermore, examples of the hydrocarbon group for R or R6 include alkyl groups such as methyl, ethyl, propyl, and butyl, aralkyl groups such as pennol, aryl groups such as phenyl, and substituted products thereof. Examples of substituents on the hydrocarbon group of R or R6 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group,
Examples include alkoxy groups such as methoxy, ethoxy, propoxy and butoxy groups, halogen atoms such as chlorine and bromine, hydroxyl and nitro groups. As a substituent on the phenyl group of R4 or the ring of
Examples of substituents on the carbocyclic group or heterocyclic group or the ring formed by R2 and R3 include a methyl group,
Alkyl groups such as ethyl, propyl and butyl groups; alkoxy groups such as methoxy, ethoxy, propoxy and butoxy; 7-rhodan atoms such as chlorine and bromine; dialkylamino such as trimethylamino and diethylamino groups. group, a dialkylamino group such as a dibenzylamino group, a halomethyl group such as a trifluoromethyl group, a nitro group, a cyan group, a carboxyl group or an ester thereof, a hydroxyl group, a sulfonic acid group (-803Na), and the like. 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, zorozyl, and butyl; alkoxy groups such as methoxy, nidoxy, propoxy, and butoxy; nitro; chlorine; Examples include halogen atoms such as bromine atoms, dialkylamino groups such as cyano groups, dimethylamine groups, and diethylamino groups.

The azo pigment used in the present invention is, for example,
It is described in No. 21728. Examples of these azo pigments are as follows.

(Leaving space below) To To To To C chin Isoseng D 饗 Ticket ■ ト〈〈国CL) ■ 〈 〈匡〇- １ - chin The charge generating layer 3 is mainly composed of an azo pigment represented by the general formula (1). There is a layer with a binder, but it can contain a binder if necessary. In this case, the proportion of the azo pigment in the charge generation layer is preferably 30% by weight or more. Since the printing original plate of the present invention elutes the non-image areas during the plate-making process, examples of binders used include alkali-soluble resins such as styrene-maleic anhydride copolymers and novolak-type phenolic resins ( (described in detail later) is preferably used. However, it is also possible to use other resins as long as the proportion of the binder is small. In addition, the charge generation layer 3
The thickness is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm. 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-oxanoazole, 2,5-bis(4-(4-diethylaminostyryl)phenyl)-1,3,4-oxanoazole, 2-(9-ethylcarbazolyl-3-
)-5-(4-diethylaminophenyl) -1,3,
oxadiazole compounds such as 4-oxadiazole;
2-vinyl-4-(2-chlorophenyl)-5-(4-
oxazole compounds such as diethylamino)oxazole, 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) birapurine, 2,2'-tumethyl-
Diphenylmethane compounds such as 4,4'-bis(diethylamino)triphenylmethane, 1,1-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 9-(4-dimethylaminobenzylidene) Fluorene, 3-(9-fluorene compound)-fluorene compounds such as -9-ethylcarbazole, 9-(4-diethylaminostyryl)anthracene, 9-bromo-10-(4-diethylaminostyryl)
Styryl anthracene compounds such as anthracene, 1.
2-bis(4-diethylaminostyryl)benzene, 1
．． Distyrylbenzene compounds such as 2-bis(2,4-dimethoxystyryl)benzene, 9-ethylcarbazole-3-fuldehyde 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-bentu-1-phenyl Hydrazone, 4-noethylaminopenzaldehyde 1,1-diphenylhydrazone, 2゜4
-Hydrazone compounds such as dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-nophenylaminobenzaldehyde 1-methyl-1-phenylhydrazone, 4-diphenylaminostilbene, 4-dibenzylaminostilpene, 4-notrylamino Stilbene compounds such as stilpen, styrylnaphthalene compounds such as 1-(4-diphenylaminostyryl)naphthalene, 1-(4-dibenzylaminostyryl)naphthalene, 4'-diphenylamino-α-phenylstilbene,
α-phenylstilbene compounds such as 4'-methylphenylamino-α-phenylstilbene, 3-styryl-
9-ethylcarbazole, 3-(4-diethylamino)
Styrylcar/J sol compounds such as styryl-9-ethylcarbazole are used.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinonomethane, 2,4,7-)linitro-9-fluorein, 2,4,5,7-tetranitro-9-fluorenone, , 4,5.7-titranitroxanthone, 2,4.
8-trinidrothioxanthone, 2.6.8-)dinitro-4H-indeno[1,2-b)thiophene-
4-one, 1,3.7-hlinitronobenzothiophene-5,5-dioxide, and the like.

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. As a resin having such characteristics, for example, styrene-maleic anhydride OL? = polymer, styrene-methacrylic acid-methacrylate copolymer, methacrylic acid-methacrylate copolymer, and phenol resin.

Examples of phenolic resins include phenol, 0-cresol, m-cresol, p-cresol, ethylphenol, isopropylphenol, t-butylphenol, t-cresol, and t-cresol.
-amylphenol, hexylphenol, t-octylphenol, cyclohexylphenol, 3+methyl-4-chloro-6-t-butylphenol, isoprobyl-cresol, t-butylcresol, t-amylcresol, hexylcresol, t-octylcresol and cyclohexyl A Nogilac type resin is used, which is obtained by condensing at least one substituted phenol such as cresol with an aldehyde such as pormaldehyde, 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.
-70 weight range, preferably 20-60 weight range. 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 extremely poor and 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 it will take a long time to elute the layer, making it impractical.

The charge transport layer 4 can contain a plasticizer.

Effective plasticizers include, for example, phthalic acid esters such as dimethyl phthalate, noethyl 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 l used in the present invention is an aluminum plate, a zinc plate, or a bimetallic plate such as a copper-aluminum plate, a copper-stainless steel plate, a chromium-copper plate, or a chromium-copper-aluminum plate, or a chromium-lead plate. −Iron [, chromium−
A conductive support with a hydrophilic surface, such as a trimetal plate of copper-stainless steel plate, is used, and its thickness is 0.1
In addition, especially in the case of a support having an aluminum surface, graining treatment, immersion treatment in an aqueous solution of IJum, potassium fluorozirconate, phosphate, etc. It is preferable to use a surface treatment such as anodic oxidation treatment. In addition, as shown in U.S. Pat. No. 2,714,066, an aluminum plate is immersed in an aqueous solution of silicic acid after graining, and anodized as shown in JP-A-47-5125. It is also preferable that the material is subsequently immersed in an aqueous solution of an alkali metal silicate.

The above-mentioned anodizing treatment is performed by applying an electric current 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 or sulfamic acid, or a salt thereof. It is carried out by flowing.

To produce the printing plate for electrophotographic engraving of the present invention, first, the pigment represented by the general formula (I) and a binder, if necessary, are mixed with, for example, tetrahydrofuran, nooxane, 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 dispersion means such as a ball mill or an ultrasonic dispersion machine. The charge generating layer 3 is provided by coating the charge generating layer 3 on a transparent support and drying it. 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 printing original plate for electrophotographic engraving of the present invention is carried out by first uniformly charging it in a dark place using a corona charger or the like according to the usual electrophotographic method, and then using a light source such as a tungsten lamp, halogen lamp, xenon lamp, or fluorescent lamp. An electrostatic latent image is formed by reflection image exposure using a transparent positive film, contact image exposure through a transparent positive film, or scanning exposure using a laser beam such as a He-Ne laser, an alcohol laser, or a semiconductor laser. The 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, and only the toner image portion remains, allowing a good printing plate to 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 triethanolamine or benzyl alcohol. , ethylene glycol, glycerin, or other organic solvents, or solutions to which surfactants are added are 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 butanoene, methacrylic acid ester, polyethylene, polypropylene and their chlorides,
Examples include polycarbonate, polyester resin, polyamide resin, phenolic resin, xylene resin, alkyd resin, wax, polyolefin, and wax.

The printing original plate of the present invention may also contain a quinonediat compound or a diazo compound, such as 0-naphthoquinone diazide, for the purpose of increasing the solubility of the shimiko photosensitive layer by 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 part, and the image part covered with the lipophilic toner remains. The oil-based ink adheres only to the image area, resulting in good prints without background smudges.

Ru.

In addition, the printing original plate of the present invention has particularly high sensitivity compared to conventional printing original plates (direct plate making is possible with various light sources such as He-Ne laser and semiconductor laser, and the printing plate obtained thereby has a high printing durability). It has a sexual nature.

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

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

Example 1 One part of Azo Pigment Shop 1 was mixed with 0.0 parts of m-cresol-phenol copolymerized novolac resin (MP-707 manufactured by Gunei Chemical Co., Ltd.).
66.7 parts of a 74 wt% tetrahydrofuran solution was pulverized and mixed in a mill, and the resulting dispersion was mixed to a thickness of about 0.2 wt%.
It was coated on a 5 mm grained aluminum plate and dried at 80° C. for 10 minutes to form a charge generation layer with a thickness of about 1 μm.

2,5-bis(
4-diethylaminophenyl) - 0.9 parts of 1,3,4-oxadiazole 1.8 parts of styrene-maleic anhydride copolymer (copolymerization molar ratio 1:1 manufactured by Aldrich Chemical Can/Enie) and Tetrahydrofuran 13.2
A printing original plate for electrophotographic engraving of the present invention was prepared by applying a solution in which the above components were mixed and dissolved and dried at 80° C. for 20 minutes to form a charge transport layer having a thickness of about 10 μm.

For this printing direct sale, using an electrostatic copying paper tester (model 5P-428 manufactured by Rodenki Manufacturing Co., Ltd.), corona discharge of -6 kV was performed for 20 seconds to negatively charge the paper, and then 1
Leave it in the dark for 0 seconds, and the surface potential V at that time. (bolt)
Next, the surface is irradiated with light using a tungsten lamp at an illuminance of 45 lux, and the time required for the surface potential to become 1/2 of vo is determined, and the half-life exposure amount E (lux seconds) was calculated. Table 1 shows the results.
Shown below.

Next, this original printing plate was applied to an electronic copying 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 mixed with 70 g of sodium metasilicate and 14 g of glycerin.
0m1. It was immersed in a solution of 550 ml of ethylene glycol and 150 ml of ethanol for 1 minute, and then washed while gently brushing with water to remove the toner and the electrophotographic photosensitive layer in the non-image areas.

The printing plate made in this way is then printed on an offset printing machine (
When printing was carried out in a conventional manner using the printer (Model AP-1310 manufactured by Ricoh), more than 50,000 clear prints could be printed.

Examples 2 and 3 Electrophotographic engraving 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 using the charge generation layer and the charge transport substance using the charge transport layer, respectively. Create a printing master plate for v. and E1/2 were measured.

The above results are shown in Table-1.

(The following is a blank space) 1゜Example 4 1 part of Azo Pigment Flat 4, 0.0% of m-cresol-phenol copolymerized novolak resin (manufactured by Gunei Chemical Co., Ltd.: MP-7079).
667 parts of a 74 wtl tetrahydrofuran solution was pulverized and mixed in a ball mill, and the resulting dispersion was mixed to a thickness of about 0.25 wtl.
It was coated on a grained aluminum plate of ynrt and dried at 80° C. for 10 minutes to form a charge generation layer with a thickness of about 1 μm.

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-7
07) A mixed solution of 3.0 parts and 120 parts of tetrahydrofuran was applied and heated at 1.80°C for 2 minutes.
A charge transporting layer having a thickness of about 10 μm was formed by drying at 0° C. for 10 minutes to prepare a printing original plate for electrophotolithography of the present invention. Regarding this printing original plate, as in Example 1, V and "
The results of measuring 1A 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 in a solution consisting of 25 parts of sodium metasilicate, x and oo parts of water for about 45 seconds,
Furthermore, the non-image electrophotographic photosensitive layer was removed by washing with water while lightly brushing.

When the printing plate made in this way was printed on an offset printing machine, more than 50,000 clear prints could be printed.

Examples 5 to 8 The electrophotographic plate of the present invention was prepared 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 a printing master plate, v.

and E+//2 were measured.

The above results are shown in Table-2.

(Margin below)

[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 To Figure 2 Figure 3

Claims (1)

[Scope of Claims] A conductive support comprising 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. A printing original plate for electrophotographic engraving characterized by being provided with an electrophotographic photosensitive layer. General formula (I) (However, in the formula, A represents all coupler residues.)