JPS60230147A - Original printing plate for electrophotoengraving - 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, with a new printing plate containing a specific azo pigment, an electrostatic latent image obtained by charging and subsequent image exposure is developed with toner and fixed to obtain a toner image, and then the non-image area is This invention relates to a printing plate that is made by elution and removal of a photosensitive layer.

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, and it is necessary to create negatives or positives from the original 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 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 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. The printing durability was about s, ooo to 10,000 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, Special Public Official Publication No. 37-17'l 62, Special Public Official Publication No. 38-77
58, Japanese Patent Publication No. 46-39405, Japanese Patent Publication No. 52-2437
, JP-A-56-107246, JP-A-55-10525
4, JP-A-55-153948, JP-A-55-1612
5, JP-A-57-147656, JP-A-56-1461
45, JP-A-57-161863, etc. disclose a layer consisting of an organic photoconductive compound and an alkali-soluble resin, or a phthalocyanine-based layer on a hydrophilic conductive support such as a grained aluminum plate. A printing original plate for electrophotographic engraving is disclosed which is provided with a layer in which a charge-generating pigment such as a 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. ing.

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.It is a printing plate with high printing durability using direct platemaking. However, it has low sensitivity as a photoreceptor for electrophotography, so
It has the drawbacks of slow plate making speed and the need to use a high output light source.

An object of the present invention is to solve the above-mentioned problems of conventional printing plates for electrophotographic printing, and to provide a printing 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 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, and a charge generation layer 3 is placed on it.
, and a charge transport layer 4 is further laminated to form an electrophotographic photosensitive layer 2.

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 amine group and a phenolic hydroxyl group, or aliphatic or aromatic enolic ketone groups (active methylene A compound having the following general formula aI) is used, preferably the coupler residue A has the following general formula aI),
Selected from the group represented by (g), (goods), (g), (b), and (6).

[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; a cyclic group or a hydrocarbon cyclic group or a substituent thereof, a heterocyclic group or a substituent thereof, a styryl group or a substituent thereof, R5 represents hydrogen, an alkyl group, a phenyl group, or a substituent thereof; , R2 and R5 may form a ring together with the carbon atom to which they are bonded. )] p゛n (Formula (to) and R4 in the ring represent a substituted or unsubstituted hydrocarbon group.) (In the formula, R5 represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, and Ar1 represents a hydrocarbon group or a substituent thereof. (In the formula, R6 is a hydrocarbon group or a substituent thereof, Ar
2 represents a hydrocarbon ring group or a substituted product thereof. ) The hydrocarbon ring represented by X in the general formula used in the present invention includes, for example, a benzene ring, a naphthalene ring, etc.
Examples of the heterocycle include an indole 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, dibenzo7ranyl group, etc., and R
Examples of the ring that 2 and R3 can form together with the carbon atoms to which they are bonded include a fluorene ring.

, Furthermore, as the hydrocarbon group in R4 or R6,
1 II'' Examples include alkyl groups such as a methyl group, ethyl group, globyl group, butyl group, aralkyl groups such as benzyl group, aryl groups such as phenyl group, or substituted products thereof. Substitution in the hydrocarbon group of R4 or R6 Examples of groups include alkyl groups such as methyl, ethyl, glopyl, and butyl; alkoxy groups such as methoxy, ethoxy, propochine, and ethoxy; 710rn atoms such as chlorine and bromine; hydroxyl and nitro. Examples of substituents on the phenyl group of R1 or the ring of X include halogen atoms such as 1, chlorine atom, bromine atom,
Also, yt or R2 carbocyclic group or heterocyclic group or R
Examples of substituents on the ring formed by 2 and R3 include alkyl groups such as methyl, ethyl, globyl and butyl groups, alkoxy groups such as methoxy, ethoxy, propoxy and butoxy groups, chlorine atoms, Norogon atoms such as bromine atoms, dialkylamino groups such as dimethylamino groups and diethylamino groups, dialkylamino groups such as dibenzylamino groups, halomethyl groups such as trifluoromethyl groups, nitro groups, cyano groups, xyl groups or Its ester, hydroxyl group, sulfonic acid group (-
8O5Nm). Furthermore, as the hydrocarbon ring group in Ar1 or Ar2, phenyl group,
Examples of substituents on these groups include alkyl groups such as methyl, ethyl, globyl, and butyl; alkoxy groups such as methoxy, butoxy, noropoxy, and butoxy; nitro; Examples include halokene atoms such as chlorine atom and bromine atom, and dialkylamino groups such as cyano group, dimethylamino group and diethylamino group.

The azo pigment used in the present invention is, for example, JP-A-56-
It is described in No. 143437. Examples of these azo pigments are as follows.

(Margin below)! The hardness generation layer 3 is an azo pigment layer represented by the general formula (I), and may contain a binder if necessary.

In this case, the proportion of pigment in the charge generating layer is preferably 30
% by weight or more, the printing original plate of the present invention dissolves the non-image areas during the plate-making process, so when using a binder, for example, styrene-maleic anhydride copolymer, lac-type phenol resin, etc. It is preferable to use an alkali-soluble fat (described in detail later). However, if the proportion of the binder is small, it is also possible to use other resins. Also, electrogenic layer 3
The thickness is preferably 0.01 to 5 μm and 0.01 to 5 μm.
05-2 μm. When the thickness is less than 1 μm, charge generation is not sufficient, and when it is more than 5 μm, the residual potential is high enough to be practical, and the load transport layer 4 is formed of a charge transport substance and an alkali-soluble material. Charge transport materials include hole materials and electron transport materials, and hole transport materials include, for example,
2,5-bis(4-dietheraminophenyl) -1,
3,4-oxanoazole, 2゜5-bis[4-(4-
diethylaminostyryl)phenyl)-1,3,4-oxadiazole, 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, l-phenyl-3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline and other pyrazoline compounds, 2,2'-dimethyl-4,4'-bis(diethylamino)triphenylmethane , l, 1-bis(4-dibenzylaminophenyl)propane, diphenylmethane compounds such as tris(4-diethylaminophenyl)methane, 9-(4-dimethylaminostylidene)fluorene, 3-(9-fluorenonedene)- 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 12-his(214-dimethoxystyryl)benzene, 9-ethylcarbazole-3-aldehyde l-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde l-benzyl-1-phenylhydrazone , 4-diethylaminobenzaldehyde 1゜1-diphenylhydrazone, 2,
Hydrazone compounds such as 4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diphenylaminobenzaldehyde 1-methyl-1-phenylhydrazone, 4-diethylaminostilbene, 4-dibenzylaminostilbene, 4-ditolyl □amino Stilbene compounds such as stilbene, styrylnaphthalene compounds such as 1-(4-diethylaminostyryl)naphthalene, 1-(4-dibenzylaminostyryl)naphthalene, 4'-diphenylamino-α-phenylstilbene, 4'-methylphenylamino -α-phenylstil,
α-phenylstilpene compounds such as pen, styrylcarbazole compounds such as 3-styryl-9-ethylcarbazole and 3-(4-diethylamino)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-indeno(1,z -b ]]thiophene-4
-one 1,3,7-trinitrodibenzothio7ene-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 characteristics include styrene-maleic anhydride copolymers, styrene-methacrylic acid-methacrylate copolymers, methacrylic acid-methacrylate copolymers, and phenol resins.

The phenolic resins include phenol, 0-cresol, m-cresol, p-cresol, ethylphenol, inzolovylphenol, t-butylphenol, t-cresol,
-amylphenol, hexylphenol, t-octylphenol, cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isozolovircresol, t-ditylcresol, t-amylcresol, hexylcresol, t-octylcresol A noblack type resin is used, which is obtained by condensing at least one substituted phenol such as cyclohexyl 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 charge and transport substance in the layer is 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 carried, 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 is insufficient, and above this range, the residual potential becomes high and it takes a long time to elute the layer, making it impractical.

The charge transport layer 4 can contain a plasticizer.

Effective plasticizers include, for example, glycol esters such as dimethyl 7-talate, diethyl 7-talate, digtylphthalate esters, 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 O,1
~1 m is preferred.

In addition, especially in the case of a support having an aluminum surface, surface treatments such as graining, immersion in an aqueous solution of sodium silicate, potassium zirconate, phosphate, etc., or anodizing are performed. Preferably. Furthermore, as shown in U.S. Pat. No. 2,714,066, an aluminum plate which is immersed in a sodium silicate aqueous solution after graining, and JP-A No. 47-5
After anodizing as shown in Publication No. 125,
Also preferred are those treated by immersion in an aqueous solution of 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 electrophotographic printing plate of the present invention, first, the pigment represented by the general formula (1) and, if necessary, a binder 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 -
A coating solution uniformly dispersed using a dispersing means such as a Lumil ultrasonic dispersion machine is coated on the conductive support and dried to form a charge generation layer 3. 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 a charge transport layer 4t. Plate making begins with the usual electrophotographic method, where it is uniformly charged in a dark place using a corona charger, etc., and then charged using a tungsten lamp, halogen lamp, or
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 with 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. After being dissolved and removed, the hydrophilic surface of the conductive support is exposed, leaving only the toner image portion 9, 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, or 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. The printing plate of the present invention uses a solution containing an organic solvent such as ethylene glycol or glycerin or a surfactant, etc. Since the printing plate of the present invention is one in which the non-image area is dissolved and removed in the eluent after the toner image is formed, It is preferable that the toner component contains a resin component having resist properties in this eluate.

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, styrene and! Copolymers such as butadiene and methacrylic esters, polyethylene, polypropylene and their chlorides, polycarbons? Examples include nates, polyester resins, polyamide resins, phenolic resins, xylene resins, alkyd resins, waxes, polyolefins, and waxes.

The printing original plate of the present invention may contain, for example, a quinone diazide compound such as 0-naphthoquinone diazide or a diazo compound for the purpose of increasing the solubility of the electrophotographic 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 area, and the image area covered with the oleophilic toner remains. It adheres only to the image area, resulting in good printed matter without background stains.

In addition, the printing original plate of the present invention has particularly high sensitivity compared to conventional printing original plates (direct plate making can be performed with various light sources such as He-Ne laser and semiconductor radar, and the printing plate obtained thereby has a high printing durability). have.

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 1 part of azo pigment A8 was mixed with 0.0 parts of m-cresol-phenol copolymerized novolak 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 applied onto a grain-treated aluminum plate with a thickness of 0.25 mm and heated at 80°C.
The mixture was dried for 10 minutes to form a charge generation layer with a thickness of about 1 μm.

2,5-bis(
09 parts of 1,3,4-oxadiazole (4-diethylaminophenyl), 1.8 parts of styrene-maleic anhydride copolymer (copolymerization molar ratio 1:1, manufactured by Aldrich Chemical Kanno-Yaney), and 13 parts of tetrahydrofuran. .2
The mixed and dissolved solution was coated and dried at 80°C for 20 minutes to give a thickness of approximately 10 μm.

A load conveying layer was formed to create a printing original plate for electrophotolithography of the present invention.

This original printing plate was tested using an electrostatic copying paper tester (newly manufactured by Kawaguchi Denki Co., Ltd.: Model 5P-428) at -6k.
After performing corona discharge of V for 20 seconds to make it negatively charged, it was left in a dark place for 10 seconds, and the surface potential v0 (yt
Then, the surface is irradiated with light using a tangent lamp at an illumination intensity of 4.5 lux: ■, and the surface potential is 1vo.
The half-reduction exposure amount EH (lux/second) was calculated based on the time required for the amount to decrease to 1/2. The results are shown in Table-□1.

Next, this original printing plate was transferred to an electronic copying plate making machine (Ricoh MS-1).
A clear toner image was formed on the charge transport layer by charging, imagewise exposure, development and fixing.

Sodium metasilicate 7011 glycerin 14
01M, ethylene glycol 550M, and ethanol 150mJ for 1 minute, and then washed with a water jet while lightly brushing, □ the electrophotographic photosensitive layer in the non-image area to which toner was not attached was removed.

The printing plate made in this way is then printed on an offset printing machine (
AP-1310 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 Printing for 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. Create the original version, v. and 8% were measured.

The above results are shown in Table-1.

(The following is a blank space) Example 4 One part of Azo Pigment Ya8 was mixed with 0.0 parts of m-cresol-phenol copolymerized 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 0.2
Coated on a 5m grained aluminum plate 8
It was dried at 0° 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 noblack resin (manufactured by Gunei Chemical: MP-
707) Applying a mixed solution of 3.0 parts and 12.0 parts of tetrahydrofuran and 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 10 μm, A printing original plate for electrophotographic engraving of the present invention was prepared. This printing original [K'i7, 5J 512 similar to K V
O$! Table 2 shows the results of 11 determinations of D''H.

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.
Furthermore, 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 way was printed on an offset printing machine, more than 50,000 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. Created the original version. and 8% 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. l... 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)

[Claims] An electronic device consisting of two layers, 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. A printing original plate for electrophotographic engraving that is characterized by the provision of a photosensitive layer. (However, in the formula, A represents a coupler residue.)