JPS60238852A - Printing original plate for electronic photoengraving - Google Patents

Abstract

PURPOSE:To obtain a printing original plate having high sensitivity and high printing resistance by providing an electric charge generating layer contg. an azo pigment expressed by the specific general formula and an electric charge transfer layer contg. an electric charge transfer material and alkali-soluble resin on a conductive base. CONSTITUTION:An electrophotographic sensitive layer consisting of the charge generating layer 3 contg. the azo pigment expressed by the formula (where A denotes a residual group of coupler) and the charge transfer layer 4 is formed on the conductive base 1 by which the printing original plate for electronic photoengraving is obtd. For example, a compd. having, a phenolic hydroxyl group such as phenol or naphthol, arom. amino compd. having an amino group or compd. contg. aminonaphthol having an amino group and phenolic hydroxyl group or having an aliphat. or arom. enol-form ketone group is used for the coupler of the azo pigment to be incorporated into the layer 3.

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 eluating and removing a photosensitive layer.

BACKGROUND ART Conventionally, as planographic 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 so-called direct plate making is not possible, and it is necessary to create negatives or positives from the original using silver halide film. For this purpose, it requires complicated equipment and has drawbacks such as 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 an acidic aqueous solution containing, for example, a ferrocyan salt in order to make the non-image area hydrophilic. The printing plates made in this way are free from the mechanical pressure applied during printing and the photosensitive layer of the dampening solution.
Penetration into the conductive treatment layer causes peeling and destroys the hydrophilic layer on the surface, so its printing durability is 5,000 to 10
It was about ,000 teachings.

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, Tokko Sho 37-7758
, JP 46-39405, JP 52-2437, JP 56-107246, JP 55-105254,
JP-A-55-153948, JP-A-55-16125,
JP-A-57-147656, JP-A-56-146145
, JP-A-57-161863, etc., disclose a layer consisting of an organic photoconductive compound and an alkali-soluble resin, or a phthalocyanine pigment, etc. on a hydrophilic conductive support such as a grained aluminum plate. A printing original plate for electrophotographic engraving is disclosed, which has a layer in which a charge-generating 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. . 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 (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 (D N=N-A (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.

The azo pigment Kagura used in the charge generation layer 3 is as follows:
For example, compounds with a phenolic hydroxyl group such as phenols and naphthols, aromatic amino 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 Kaglar residue A has the following general formula (n),
GID, (IV).

(G), (B)1. (7)).

X' [wherein, R4 is hydrogen, an alkyl group, a phenyl group, or a substituted product thereof; a substituent thereof, a heterocyclic group or a substituent thereof, or a styryl group or a substituent thereof, R3 represents hydrogen, an alkyl group, a phenyl group, or a substituent thereof, or R2 and R3 represent Together with the carbon atoms to which they are bonded, they may form a ring. )] (R4 in formula (g) and ω represents 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 carboxylic acid group. 1J 60 (wherein, R6 is a hydrocarbon group or a substituent thereof, Ar
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 for Y or R2, such as insifurane ring, include phenyl group, naphthyl group, anthryl group,
Examples of heterocyclic groups such as pyrenyl group include pyridyl group, chenyl group, furyl group, indolyl group, benzofuranyl group,
Examples of the ring that can be formed by R2 and R5 together with the carbon atoms to which they are bonded include a carbazolyl group, a sopenzofuranyl group, and a fluorene ring.

Furthermore, examples of the hydrocarbon group for R4 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 in the carbocyclic group or heterocyclic group of 2 or the term that can be formed by R2 and R3 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; noarakylamino groups such as dibenzylamino; Examples include halomethyl groups such as fluoromethyl groups, nitro groups, cyano 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, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; nitro; chlorine; and bromine. Examples include halogen atoms such as , and alkylamino groups such as an ano group, a dimethylamino group, and a diethylamino group.

The azo pigment used in the present invention is, for example,
It is described in No. 20737. Examples of these azo pigments are as follows.

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″″′ The charge generation layer 3 is a layer mainly composed of an azo pigment represented by the general formula (I), but it may contain a binder if necessary. can. In this case, the proportion of azo pigment in the charge generating layer is preferably on a 30-weight plate. Since the printing original plate of the present invention elutes the non-image areas during the plate-making process, when using a binder, examples of the binder include alkali-soluble resins such as styrene-maleic anhydride copolymer, /g-lac type tuffenol resin, etc. (described in detail later) is preferable. However, if the proportion of the binder is small, it is also possible to use other resins. The thickness of the charge generation layer 3 is preferably 0.01 to 5 μm, more preferably 0.01 to 5 μm.
05-2 μm. If the thickness is less than 0.001 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-bisC4-C4-diethylaminostyryl)phenyl) -1,3,4-oxadiazole, 2-(9-ethylcarbazolyl-3-)
-5-(4-diethylaminophenyl) -1,3,4
-Oxadiazole compounds such as oxadiazole, 2
-vinyl-4-(2-chlorophenyl)-5-(4-diethylamino)oxazole, oxazole compound of 2-(4-diethylaminophenyl)-4-phenyloxazole, ■-phenyl-3-(4-diethylaminostyryl) -5-(4-diethylaminophenyl)pyrazoline, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline and other pyrazoline compounds, 2,2'-dimethyl-4
, 4'-bis(diethylamino)triphenylmethane,
1. ．． Diphenylmethane compounds such as 1-bis(4,-shihendylaminophenyl)furopane and tris(4-diethylaminophenyl)methane, 9-(4-dimethylaminobendiIJ7')fluorene, 3-(9-fluorene compounds) )-9-ethylcarbazole and other fluorene compounds, 9-(4-diethylaminostyryl)anthracene, 9-7'rom-10-(4-diethylaminostyryl)anthracene and other styrylanthracene compounds, ■,2-bis(4- diethylaminostyryl)benzene, 1,2-bis(2,4-dimethoxystyryl)
Distyrylbenzene compounds such as benzene, 9-ethylcarbazole-3-fuldehyde 1.-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminopenz Aldehyde t,t-diphenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-dibuenylaminobenzaldehyde 1-methyl-1-phenylhydramonofemale hydrazone compound, 4-diphenylaminostilbene, 4 -Stilbene compounds such as dibenzylaminostilbene, 4-ditolylaminostilbene, 1-(4-
Styrylnaphthalene compounds such as diphenylaminostyryl)naphthalene, 1-(4-dibenzylaminostyryl)naphthalene, 4'-diphenylamino-α-phenylstilbene, 4'-#-f ruphenylamino-α-phenylstilbenato α-Phenylstilbene compound, 3-styryl-9-ethylcarbazole, 3-(4
A styrylcarbazole compound such as -cyxf-ylamino)styryl-9-ethylcarbazole is used.

Examples of electron transport substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,417-t! J nitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorene, 2,4,5,7-titranitroxanthone, 2,4.
Examples include 8-trinidrothioxanthone, 2,6.8-trinitro-4H-indeno[j,2-b]]thiophen-4-one, 11317-trinitrocyhenzothiophene-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. Examples of resins having such characteristics include styrene-maleic anhydride copolymers, styrene-methacrylic acid-methacrylate copolymers, methacrylic acid-methacrylate copolymers, and phenol resins.

Examples of the phenolic resin include phenol, 0-cresol, m-cresol, p-cresol, ethylphenol, inzolovylphenol, t-butylphenol, and t-cresol.
-amylphenol, hexylphenol, t-octylphenol, cyclohexylphenol, 3-. 7'
-F-- at least one substituted phenol such as 4-chloro-6-t-butylphenol, isopropyl cresol, t-butyl cresol, t-amyl cresol, hexyl cresol, t-octyl cresol and cyclohexyl cresol, formaldehyde, acetaldehyde, A novolac type resin obtained by condensing aldehyde Ps such as acrolein, crotonaldehyde, and furfural under acidic conditions is used.

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 to 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 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 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, diethyl phthalate, and digtylphthalate, 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 copper-aluminum plate, a copper-stainless steel plate, a chromium-copper plate, a chromium-copper-aluminum plate, a chromium-lead- A conductive support with a hydrophilic surface such as a tri-metal plate such as an iron plate or a chrome-copper-stainless steel plate is used, and its thickness is O6.
1 to 1tIa 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. No. 2,714,066, an aluminum plate which is immersed in a sodium silicate aqueous solution after graining, and JP-A No. 47-5
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 Publication No. 125°.

In the above anodizing treatment, an aluminum plate is anodized 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 passing a current as .

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

The plate making of the original plate for electrophotographic platemaking of the present invention is performed by first uniformly charging the original plate in a dark place with a corona charger, etc. using a corona charger, and then using a tungsten lamp, halogen lamp, xenon lamp, or fluorescent lamp. reflection image exposure using a light source, contact image exposure through a transparency film, or
Scanning exposure is performed using a laser beam such as a He-Ne laser, an argon laser, or a semiconductor laser to form an electrostatic latent image, and this electrostatic latent image is developed with toner.
A toner image is obtained on the electrophotographic photosensitive layer by heating and fixing (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, or an alkaline aqueous solution containing organic amines such as triethanolamine or ethylenenoamine; A solution containing an organic solvent such as benzyl alcohol, ethylene glycol, or glycerin or a surfactant added thereto 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 7 dust 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, borizolopyrene and its chloride,
Polycar? nates, polyester resins, polyamide resins, phenolic resins, xylene resins, Alkyra resins, waxes, polyolefins, waxes, etc.

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 electrophotographic photosensitive layer by full-surface photometry after toner image formation.

In the original printing 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. 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 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 1 part of Azo Pigment Boiled 1 was mixed with 0.0 parts of m-cresol-phenol copolymerized novolak resin (manufactured by Gunei Chemical Co., Ltd.: MP-707).
667 parts of a 74 wt trahydrofuran solution was pulverized and mixed in a sol mill, and the resulting dispersion was mixed to a thickness of about 0.25 mm.
The mixture was coated on a grain-treated 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(
09 parts of 4-diethylaminophenyl)-L3,4-oxadiazole, 09 parts of styrene-maleic anhydride copolymer (manufactured by Aldrich Chemical Co., Ltd., copolymerization molar ratio: 1)
:1) A solution prepared by mixing and dissolving 1.8 parts and 13.2 parts of tetrahydrofuran was coated and dried at 80° C. for 20 minutes to form a charge transport layer with a thickness of about 10 μm. Created the original printing plate.

This original printing plate was tested at 16kV using an electrostatic copying paper tester (newly manufactured by Kawaguchi Denki Co., Ltd.: Model 5P-428).
After performing corona discharge for 20 seconds to make it negatively charged,
Leave it in a dark place for 10 seconds, and the surface potential Vo (+x
The silt is measured, and then the surface is irradiated with light using a tungsten lens at an illuminance of 4.5 lux, and the surface potential is v.

The half-reduced exposure amount EIA (lux seconds) was calculated based on the time required for the difference to occur. The results are shown in Table-1.

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 made of sodium metasilicate 70.9. Glycerin 1
40d, ethylene glycol 550m7! The electrophotographic photosensitive layer was then immersed in a solution consisting of 150 d of ethanol for 1 minute, and was further lightly brushed with water to remove the electrophotographic photosensitive layer in the non-image area to which the washing 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.) was used for printing according to a conventional method, and more than 50,000 clear prints could be printed.

Examples 2 and 3 The electrophotographic plate of the present invention was prepared in the same manner as in Example 1, except that the age pigment used in the charge generation layer and the charge transport material used in the charge transport layer were the compounds shown in Table 1, respectively. Created the original printing plate, and V.

and E1/! was measured.

The above results are shown in Table-1.

(The following is a blank space) Example 4 One part of Azo Pigment Flat 4 was mixed with 0.0 parts 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 0.2
It was coated on a 5 tan grained aluminum plate 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-ethylcarbasol, m-cresol-phenol copolymerized noblack resin (manufactured by Gunei Chemical: MP-
707) A mixed solution of 3.0 parts and 120 parts of tetrahydrofuran was applied and heated at 80°C for 2 minutes, followed by 1
A charge transporting layer having a thickness of about 10 μm was formed by drying at 00° C. for 10 minutes, thereby producing a printing original plate for electrophotolithography of the present invention. Regarding this printing original plate, Vo and E]7% 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 in a solution of 2.5 parts of sodium metasilicate and 100 parts of water for about 45 seconds.
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 were 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. A printing original plate was prepared, and vO and Ey2 were measured.

The above results are shown in Table-2.

(Margin below)

[Brief explanation of the drawing]

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, where 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. . 1... Conductive support, 2... Electrophotographic photosensitive layer, 3...
- Charge generation layer, 4... Charge transport layer, 5... Toner image. Patent applicant Rico Co., Ltd. - Figure 18 - Figures 2 and 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, characterized by being provided with a photosensitive layer. General formula (I) (However, the person in the formula represents a coupler residue.)