JPS61217292A - Plate blank for electronic photo plate-making process - Google Patents

Abstract

PURPOSE:To obtain a plate blank high in sensitivity and durability in printing and easy to manufacture, by a method wherein an electric charge feeding layer is provided on a conductive base, and an electric charge generating layer comprising an electric charge generating substance and a silylated polyvinyl alcohol or a reaction product thereof with a crosslinking agent is provided thereon. CONSTITUTION:The electric charge feeding layer 2 comprising an electric charge feeding substance as a main constituent is provided on the conductive base 1, and the electric charge generating layer 3 comprising an electric charge generating substance and a silylated polyvinyl alcohol or a reaction product thereof with a crosslinking agent and having a surface which can be made to be hydrophilic is provided thereon. The silylated polyvinyl alcohol or the reaction product, per se, is hydrophobic and has sufficient resistance for holding an electrostatic latent image, but when it is treated with an acidic or alkaline aqueous solu tion, silyl ether groups are hydrolyzed to form original hydroxyl groups, thereby providing hydrophilic nature, which enables printing. Since the surface of the layer 3 becomes hydrophilic but not water-soluble and has sufficient water resistance, durability in printing can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a printing original plate for electrophotographic printing, and more particularly to a printing original plate whose surface is made hydrophilic after forming a toner image by electrophotography.

BACKGROUND OF THE INVENTION Hitherto, as a lithographic printing original plate, a photosensitive material using a photosensitive resin or a silver halide photosensitive material has 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, large-scale equipment is required, and there are 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 io
, ooo sheets.

Further, zinc oxide/resin dispersion printing plates are subjected to dye sensitization 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, there is a drawback that exposure cannot be performed using a low-output and inexpensive He-Ne laser or semiconductor laser.

On the other hand, the special public service No. 37-17162, the special public service No. 38-7758
, JP 46-39405, JP 52-2437, JP 56-107246, JP 55-105254
, JP-A-55-153948, JP-A-56-1612
5, JP-A-57-147656, JP-A-56-146
145, JP-A No. 57-161863, etc., for example, a photoconductive material consisting of an organic photoconductive compound and an alkali-soluble resin on a hydrophilic conductive support such as a grained aluminum plate, or Printing for electrophotographic printing that has 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. The original version is shown.

This persimmon 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.
The M plate has the advantage of producing printing plates with high printing durability, but it has the disadvantages of low sensitivity as a photoreceptor for electrophotography, resulting in slow platemaking speed and the need to use a high-output light source. had.

Further, Japanese Patent Publication No. 5606/1989 discloses a method for preparing a printing plate of a hydrophilic treatment type on the surface of a non-image area, which is easy to make by providing a specific resin layer on an ordinary electrophotographic photoreceptor. That is, a printing plate is disclosed in which a surface layer comprising a vinyl ether-maleic anhydride copolymer and a hydrophobic resin compatible therewith is provided on an electrophotographic photosensitive layer. This layer is a layer that can be made hydrophilic by treating the non-image area with an alkali to open the acid anhydride ring portion with water after the toner image is formed.

However, the vinyl ether-maleic anhydride copolymer used here becomes water-soluble when the acid anhydride ring portion is ring-opened and made hydrophilic, and therefore high rigidity resistance cannot be obtained. If the proportion of hydrophobic resin in the layer is increased in order to improve water resistance, the hydrophilicity of the surface will decrease, causing background stains on printed matter, so it has been difficult to achieve both hydrophilicity and water resistance.

Purpose The purpose of the present invention is to solve the above-mentioned problems of conventional printing plates for electrophotographic printing, and to provide a printing plate that has particularly high sensitivity, high printing durability, and is easy to plate. .

Structure The printing original plate for electrophotographic engraving of the present invention has a charge transporting layer containing a charge transporting substance as a main component on a conductive support, and a charge transporting layer containing a charge generating substance and a silylated polyvinyl alcohol or a silylating agent on the charge transporting layer. It is characterized by providing a charge generation layer whose surface is made of a reaction product of the silylated polyvinyl alcohol and a crosslinking agent and whose surface can be made hydrophilic.

Here, trimethylsilylated polyvinyl alcohol is a typical example of silylated polyvinyl alcohol.
Moreover, a polyisocyanate compound is mentioned as a typical example of a crosslinking agent.

Hereinafter, the present invention will be explained in detail based on the accompanying drawings.

FIG. 1 is a sectional view showing the basic structure of the printing original plate of the present invention. In the figure, 1 is a conductive support, 2 is a charge transport layer, and 3 is a charge generation layer whose surface can be made hydrophilic.

The charge generation layer 3 contains a charge generation substance as described above, and in the image forming process by electrophotography,
At the time of image exposure after charging, the charge-generating material absorbs light in the portion irradiated with light, and electrons and holes are generated.

Electrons and holes are injected by the electric field into the charge transport layer 2, through which they flow to the conductive support, where they neutralize the surface charge and form an electrostatic latent image. At this time,
The surface of the layer 3 that holds the electrostatic latent image must be highly resistive and hydrophobic to the extent that no charge diffusion occurs in the surface direction (
If it is hydrophilic, it will absorb moisture and have low resistance, making it impossible to retain an electrostatic latent image).

The electrostatic latent image is then developed with toner charged to the opposite polarity to the surface charge and fused to form a toner image on layer 3. Since printing is performed based on the difference between the lipophilicity (inkphilicity) of the toner image thus formed and the hydrophilicity of the non-image area, the surface of the layer 3 needs to be hydrophilic during printing.

In this way, the layer 3 is required to have the function of changing from hydrophobicity during electrostatic latent image formation to hydrophilicity during printing, in addition to generating charge. The silylated polyvinyl alcohol or the reactant with the silylated polyvinyl alcohol crosslinking agent used in layer 3 in the present invention is hydrophobic in nature and has sufficient resistance to retain the electrostatic latent image. However, when treated with an acidic or alkaline aqueous solution, the silyl ether group is hydrolyzed and returns to its original hydroxyl group, making it hydrophilic and enabling printing. Moreover, although it is hydrophilic, it is not water-soluble.
High printing durability is achieved due to sufficient water resistance.

Examples of the charge generation substance used in the hydrophilic charge generation layer 3 of the present invention include inorganic compounds such as zinc oxide, titanium oxide, zinc sulfide, selenium, selenium alloys, cadmium sulfide, cadmium selenide, and silicon; Examples include organic compounds as shown in (1) to (141) below.

(1) Triphenylmethane pigments such as malachite green and crystal violet, methylene blue,
Thiazine dyes such as methylene green, Astrazone dyes such as Astrazone Orange R1, Astrazone Yellow 30I, Astrazone Colors such as Astrazone Red 6'B, Cyanine Colors X such as Eisen Astrafuroxin FF, O-Damine B
xanthine dyes such as 2,6-diphenyl-4-(N
, N-dimethylaminophenyl) thiapyrylium nosochlorate, benzobyrylium salts, and other pyrylium dyes.

(2) Perylene pigments such as perylene anhydride and perylene imide.

(3) Indigo pigment.

(4) Quinacridone pigment.

(5) Polycyclic quinones such as anthraquinones, zelenoquinones, anthorthros, and furanoquinones.

(6) Bisbenzimidazole pigment.

(7) Square methine pigment.

(8) Indathlon pigment.

(9) Phthalocyanine pigments such as metal phthalocyanines such as copper phthalocyanine and metal-free phthalocyanines.

αQ A charge transfer type casting body comprising an electron-donating substance such as polyN-pynylcarnozole and an electron-accepting substance such as 2.4.7-dolinitrofluorenone.

01) A eutectic complex formed from a pyrylium salt dye and a polycarbonate resin.

(12) Norrhylic acid derivatives or thionorurbituric acid derivatives.

Group 0 Azo pigments such as monoazo pigments, disazo pigments and trisazo pigments. Examples of monoazo pigments include monoazo pigments having a central skeleton such as anthraquinone and N-7 enylcarnozole; examples of disazo pigments include benzidine pigments such as ``Diamond blue'' and chlordiane blue; N-ethylcarbazole,
Mainly stilbene, distilbenzene, naphthalene, fluorenone, traquinone, 2.5-diphenyl-1,3゜4-oxadiazole, dipenzothiophene, dipenzothiophene dioxite, acridone, phenanthrenequinone, etc. Examples of the disazo pigment having a skeleton include trisazo pigments having a central skeleton of triphenylamine or N-phenylcarnozole.

Silylated polyvinyl alcohol can be obtained by reacting polyvinyl alcohol with a silylating agent in an organic solvent. As the silylating agent, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, t-butyldimethyldichlorosilane, dimethylchlorosilane, cyphenyldichlorosilane, triphenylchlorosilane, triethylfluorosilane, trimethylbromine Norosilanes such as silane; hexamethyldisilazane, N,N-dimethylaminotrimethylsilane, N,N-diethylaminotrimethylsilane, dimethylsilyldimethylamine, dimethylsilyldiethylamine, heptamethyldisilazane, nanomethyltrisilazane,
Silylamines such as tetramethyldisilazane; bis(
trimethylsilyl)acetamide, bis(dimethylsilyl)acetamide, N-methyl-N-)limethylsilylacetamide, bis(trimethylsilyl)trifluoroacetamide, N-methyl-N-)limethylsilylacetamide, N-trimethylsilylacetamide, trimethylsilyl Silylamides such as diphenyl urea and bistrimethylsilylurea; trimethyltrifluoromethylsulfonate, N-trimethylsilylpiperidine, N-
) Limethylsilylimidazole, 1-phenyl-4-drimethylsilyl-5-tetrazolinone, trimethylacetoxysilane, etc. can be used.

Among these, if the hydrophilizable layer 2 is formed of trimethylsilylated polyvinyl alcohol obtained using a trimethylsilylating agent such as trimethylchlorosilane, hexamethyldisilazane, or bis(trimethylsilyl)acetamide, the hydrophilic property can be improved. It has the advantage of being able to be hydrolyzed quickly.

Silylation of polyvinyl alcohol can be carried out using silylating agents such as those mentioned above, for example, as described by Bredereek.

K, 8trunk+ H, MenracL Die
Makromoleculare Ohemie 1
26,139 (1969) or JP-A-55-164
614, the reaction is carried out in the presence of an organic solvent that does not react with the silylating agent, such as N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, toluene, pyridine, triethylamine, etc., or can be easily synthesized by direct reaction without using a solvent.

The raw material polyvinyl alcohol has a saponification degree of 98.
Either ~100 mol% fully saponified polyvinyl alcohol or 70-98 mol% partially saponified polyvinyl alcohol can be used. In addition, in this silylation reaction,
From the relationship between the hydrophobicity and water resistance of the layer, 5 of the hydroxyl groups contained
It is desirable to carry out silylation of 0% or more. If it is less than this, the water resistance of the layer will not be sufficient and the printing durability will also be low. In addition, when reacting with a crosslinking agent, it is recommended to limit the silylation reaction to about 95% of the hydroxyl groups in order to react the hydroxyl groups remaining without being silylated in the silylated polyvinyl alcohol with the crosslinking agent. preferable. If the silylation is 95% or more, crosslinking will not be sufficient and good printing durability will not be obtained.

A typical example of the crosslinking agent is a polyisocyanate compound. Polyisocyanate compounds include toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.
Diisocyanate, naphthylene-1,5-diisocyanate, 3゜3'-dimethylpiphenyl-4,4'-diisocyanate, triphenylmethane-4,4',4'-
) aromatic polyisocyanates such as p-incyanate, tris(p-incyanate phenyl) thiophosphite, polymethylene polyphenyt isocyanate, xylylene diisocyanate, or fats such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate. Examples include polyisocyanates of the group polyisocyanates, or trimers and trimers thereof. The charge transport layer 2 mainly contains a charge transport substance,
It is formed using a binding resin if necessary. Charge transporting substances include hole transporting substances and electron transporting substances, and examples of hole transporting substances include 2.5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, 2.
5-bis(4-(4-diethylaminostyryl)phenyl)-1,3,4-oxacyazole, 2-(9-ethylcarbazole-3-)-5-(4-diethylaminophenyl)-1,3, Oxadiazole compounds such as 4-oxadiazole, 2-vinyl-4-(2-chlorophenyl)-S-(4-diethyl7mi/)oxazole, 2
Oxazole compounds such as -(4-diethylaminophenyl)-4-phenyl'oxazole, 1-phenyl-
3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, 1-phenyl-3-
pyrazoline compounds such as (4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline;
Diphenylmethane compounds such as 2,2'-dimethyl-4゜4'-bis(diethylamino)triphenylmethane, 1,1-bis(,i-dibenzylaminophenyl)furonone, tris(4-diethylaminophenyl)methane , 9-(4-dimethylaminobenzylidene)fluorene, 3-(Q-fluorenonedene)-9-ditylcarnomazole and other fluorene compounds, 9-(4-diethylaminostyryl)anthracene, 9-bromo-10-( 4
styryl anthracene compounds such as -diethylaminostyryl)anthracene, distyrylbenzene compounds such as 1,2-bis(4-diethylaminostyryl)benzene, 1,2-bis(2,4-dimethoxystyryl)benzene, 9-ethylcarbazole- 3-Aldehyde 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde 1,1-diphenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl- Hydrazone compounds such as 1-phenylhydrazone, 4-diphenylaminobenzaldehyde 1-methyl-1-phenylhydrazone, 4-diphenylaminostilbene, 4-dibenzylaminostilbene,
Stilbene compounds such as 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene,
Styrylnaphthalene compounds such as 1-(4-diethylaminostyryl)naphthalene, 4'-diphenylamino-
α-phenylstilbene, α-phenylstilbene compounds such as 4′-methylphenylamino-α-phenylstilbene, 3-styryl-9-ethylcarbazole, 3
A styrylcarnozole compound such as -(4-diethylamino)styryl-9-ethylcarbazole or a polymer compound such as poly-N-vinylcardazole is used.

Examples of the electron transport substance include chloranil, fromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-dolinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4゜5.7-Titranitroxanthone, 2,4.8
-trinitrothioxaton, 2,6.8-trinitro-4I-indeno(x,2-b)thiophen-4-one, 1,3.7-)linitrodibenzothiophene-5,
Examples include 5-dioxide.

Examples of the binding resin include polyester resin, polycarbonate a resin, acrylic resin, polystyrene, polyamide, polyacrylamide, polyvinyl acetal, and polyvinyl butyral.
゛As the conductive support 1, for example, a plastic film having a conductive surface such as an aluminum vapor-deposited film; paper treated with water resistance, solvent resistance, and conductivity treatment; metal plates such as an aluminum plate, a zinc plate, a copper plate, and a stainless steel plate; used.

To produce the electrophotographic printing plate of the present invention, 1.
The above charge transport substance and binding resin are mixed with a suitable organic solvent such as tetrahydrofuran, dioxane, dimethylformamide, acetone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethyl acetate, butyl acetate, toluene, halogenated A solution dissolved in a hydrocarbon or the like is applied onto a conductive support and dried to provide a charge transport layer 2.

Next, a charge generating substance is added to a solution of silylated polyvinyl alcohol dissolved in the same organic solvent as above, and the uniformly dispersed liquid is applied onto the charge transport layer using a dispersing means such as a Zeel mill or an ultrasonic disperser. Dry to form charge generation N3.

In addition, when reacting with a crosslinking agent, a coating solution prepared by adding a crosslinking agent such as a polyincyanate compound to the dispersion is applied onto the charge transport layer, dried, and further heat-treated to cause a crosslinking reaction to form the charge generation layer 3. Form.

When performing a crosslinking reaction, a heat treatment may be performed to cause a crosslinking reaction between the hydroxyl groups remaining without being silylated in the silylated polyvinyl alcohol and the polyincyanate compound. This heat treatment can also be performed simultaneously with drying. Also, the humidity and time of heat treatment are determined by the temperature of the silylating agent.
Type 1, although it varies depending on the degree of silylation, the type of polyisocyanate compound, etc., it can be selected in the range of approximately 50 to 200 C1 from several minutes to several hours.

In order to promote the crosslinking reaction, catalysts such as diptyltin dilaurate, dibutyltin diacetate, lead 2-ethylhexanoate, titanium tetrabutoxide, tin octoate, dibutyltin di(
Metal compounds such as 2-ethylhexoate), O-phenylunda, potassium oleate, bismuth nitrate, 2-ethylhexyl titanate, tin chloride, zinc naphthenate, and antimony trichloride, or amines such as triethylamine and triethylenediamine. can be added in an appropriate amount.

The main material is silylated polyvinyl alcohol, but in order to improve the strength of the layer, other resins such as polyester resin, polyamide resin, polycarzenate resin, acrylic resin, polystyrene resin, vinyl acetal resin or vinyl acetate resin are used. etc. can be added.

However, in this case, the proportion of these resins contained in the entire layer is preferably 50% by weight or less. If it exceeds this range, the rate of hydrophilic treatment of the surface of the non-image area performed after image formation will be slow and the hydrophilicity will be insufficient, and background stains will occur on the printed matter.

The proportion of the charge generating substance in the hydrophilic charge generating layer 3 is as follows:
Preferably 10 to 80% by weight, more preferably 20 to 80% by weight
It is 70% by weight. Below this range, sensitivity is low, and above this range, printing durability is reduced. In addition, the charge generation layer 3
The thickness is preferably 0.05 to 5 μm, more preferably 0.1 to 2 μm. Below this range, the sensitivity is low, and above this range, the residual potential is high and causes staining of the background.

The proportion of the charge transport material in the charge transport layer 2 is from 10 to 95% by weight, preferably from 30 to 90% by weight. Below this range, the sensitivity is low, and above this range, the mechanical strength of the layer decreases and is not practical. Further, the thickness of the charge transport layer 2 is preferably 3 to 50 μm2, more preferably 5 to 2 μm2.
It is 0 μm. Below this range, charging will not be sufficient, and above this range, the residual potential will be high and cause staining of the background.

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.
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 1 (e-No laser, argon laser, or semiconductor laser) is performed to reduce electrostatic potential. An image is formed, 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 original plate on which this toner image has been formed is immersed in an acidic or alkaline parent wood treatment solution, the surface of the non-image area (the surface of the charge generation layer 3) that is not masked by the toner image becomes hydrophilic, resulting in good printing. You can get the version.

Examples of acidic aqueous solutions include aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, oxalic acid, acetic acid, and sulfamino acid, and examples of alkaline aqueous solutions include aqueous solutions of inorganic salts such as sodium silicate, sodium phosphate, and sodium hydroxide, aqueous ammonia, or triethanol. Examples include aqueous solutions containing organic amines such as amines and propatool amines. Organic solvents and surfactants such as ethanol, benzyl alcohol, ethylene glycol, and glycerin may be added to the hydrophilic treatment liquid as necessary.

The rate of hydrophilization of silylated polyvinyl alcohol (
That is, although it varies depending on the type of silylating agent, the degree of silylation) and the formulation of the hydrophilic treatment liquid, it is possible to easily reduce the time to about 20 to 60 seconds/plate by selecting appropriate conditions.

Since the printing original plate of the present invention is subjected to hydrophilic treatment only on the non-image areas, it is preferable that the toner component contains a resin component having resistivity in the hydrophilic treatment liquid.

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, polyethylene, polypropylene and its chloride, polycarbonate, polyester resin, polyamide resin, phenolic resin, These include xylene resin, alkyd resin, wax, polyolefin, and wax.

After completing the plate-making process described above, the printing original plate of the present invention becomes a printing plate having an image area covered with lipophilic toner and a surface of a non-image area that has been made highly hydrophilic. It adheres only to the surface of the paper, resulting in good printed matter with no background stains.

Furthermore, the printing original plate of the present invention has particularly high sensitivity compared to conventional printing original plates, and the selection of charge-generating substances allows fi He
Direct plate making is possible using various light sources such as -Ne laser and semiconductor laser.

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 Polyvinyl alcohol (manufactured by Furan Co., Ltd., Honol 217)
:Saponification degree 87-89 mol%, average degree of polymerization 1700) 4
．． After heating and dissolving 4 parts in 170 parts of N,N-dimethylformamide and cooling it to room temperature, 12 parts of triethylamine and 13 parts of trimethylchlorosilane were added to this,
The mixture was allowed to bend at room temperature for 3.5 hours to obtain 9.6 parts of trimethylsilylated polyvinyl alcohol. The infrared absorption spectrum of this product is 9 as shown in FIG.

Example 2 10 parts of a charge transporting substance represented by the following structural formula (I) and a polycarbonate resin (Panrye) K-
A solution consisting of 10 parts of 130'0 (manufactured by Jojin Kasei Co., Ltd.) and 80 parts of tetrahydrofuran was applied and heated at SOC for 2 minutes.
Subsequently, it was dried at 105C for 5 minutes to form a charge transport layer with a thickness of about 17 μm.

2H5 On this charge transport layer, 1 part of a disazo pigment represented by the following structural formula (It) and 10 parts of a 2% by weight toluene solution of trimethylsilylated polyvinyl alcohol obtained in Example 1 were added.
A dispersion obtained by sufficiently pulverizing and mixing 0 part with a seal mill was applied and dried at 100 C for 5 minutes to form a hydrophilic charge generation layer having a thickness of about 0.8 μm.

The planographic printing original plate thus obtained was positively charged by +6KV corona discharge for 20 seconds using an electrostatic copying paper tester (Model 5P-428 manufactured by Kawaguchi Electric Seisakusho Co., Ltd.), and then positively charged for 20 seconds. Leave it in a dark place, and the surface potential Vp at that time
o (volts), then irradiate the surface with light using a tungsten lamp so that the illumination intensity is 4.5 lux, calculate the time (seconds) until the surface potential reaches % of Vpo, and half-exposure. The amount E% was calculated. The result is V
po=+1650 (volts), Ey6=42 (lux seconds).

Next, this printing original plate was heated to approximately 800% by corona discharge in a dark place.
After being completely charged, the electrostatic latent image was imagewise exposed using a tungsten light source, and the resulting electrostatic latent image was developed with toner and fixed by heating to form a toner image.

Next, in order to make the non-image area of the printing original plate on which the toner image was formed hydrophilic, it was immersed for 30 seconds in a hydrophilic treatment solution consisting of 1 part of 2% hydrochloric acid and 2 parts of ethanol, washed with water, and dried.

When the printing plate thus prepared was printed using a Ricoh offset printing machine model AP-1310 according to a conventional method, more than 3,000 clear prints without background stains were printed.

Example 3 Toluene-2,
The same procedure as in Example 2 was carried out, except that 0.29% of 4-diisocyanate was added and a step of heat treatment at 150C for 30 minutes after coating and drying was added.

The results obtained are shown below.

Vpo = + 1680 gk E% = 4.3 lux Printing durability = 3000 sheets or more Example 4 Charge transport material 10 represented by the following structural formula (1) was placed on a 100 μm thick polyester film coated with aluminum. part, polycarbonate resin (same as Example 2) 1
A solution of 0 parts and 80 parts of tetrahydrone was applied and dried at 80C for 2 minutes, followed by 5 minutes at 105C to form a charge transport layer approximately 18 microns thick.

On this charge generation layer, 1 part of a disazo pigment represented by the following structural formula (6)) and 10 parts of a 2% by weight toluene solution of trimethylsilylated polypinyl alcohol obtained in Example 1 were applied.
A dispersion solution obtained by sufficiently pulverizing and mixing 0 part with a seal mill was coated and dried at 100 C for 5 minutes to form a hydrophilic charge generation layer having a thickness of about 0.8 μm.

Regarding the printing original plate obtained in this way, Vpo and E% were measured in the same manner as in Example 2, and it was found that Vpo = 15
00 (volts), E%=4.0 (lux seconds).

A toner image was formed on this original plate in the same manner as in Example 2, and then the non-image area was made hydrophilic to form a printing plate. When the printing plate was printed on a printing machine, clear prints with no background stains were obtained.
I was able to print 0 or more pages.

Example 5 Toluene-2,
The same operation as in Example 4 was carried out, except that 0.2 part of 4-diisocyanate was added and a step of heat treatment at 150C for 30 minutes after coating and drying was added.

The results obtained are shown below.

Vpo = +1440 Dalt E% = 4.0 lux/second Printing durability = 3000 sheets or more Example 6 A charge transport layer was formed in the same manner as in Example 2 on a 100 μm thick polyester film on which aluminum was vapor-deposited. On top of this, 1 part of a trisazo pigment represented by the following structure and formula (g) and 100 parts of a 2% by weight toluene solution of trimethylsilylated polyvinyl alcohol obtained in Example 1.
Apply a dispersion solution which thoroughly pulverizes and mixes the parts in a dill mill,
] It was dried for 5 minutes at OOC to form a hydrophilic charge generation layer having a thickness of about 0.8 μm.

Regarding the planographic printing original plate thus obtained, Vpo and E% were measured in the same manner as in Example 2.
= +1460 (yf silt E% = 2.5 (lux・
seconds).

Further, when a toner image was formed in the same manner as in Example 2 and the non-image area was made hydrophilic, the printing plate was printed using a printing machine, and more than 3000 clear prints without background stains were printed.

Example 7 Toluene-2,
The same procedure as in Example 6 was carried out, except that 0.2 part of 4-diisocyanate was added and a step of heat treatment at 150° C. for 30 minutes after coating and drying was added.

The results obtained are shown below.

Vpo = + 1670 g Rut E = 2.2 lux / seconds Printing life = 3000 sheets or more Effect As stated above, according to the present invention, high sensitivity, high printing durability, and plate making are possible. A printing original plate that is easy to print can be obtained.

[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. FIGS. 2 and 3 are diagrams explaining the plate-making process of the printing original plate of the present invention. FIG. 2 shows a state in which a toner image has been formed, and FIG. 3 shows a state in which a non-image area has been made hydrophilic. . FIG. 4 is an infrared absorption spectrum diagram of trimethylsilylated polyvinyl alcohol. 1... Conductive support 2... Charge transport layer 3...
Charge generation layer 4 that can be made hydrophilic...Image 5...Charge generation layer P, J partially rendered hydrophilic Figure 1

Claims (1)

[Claims] 1. A charge transporting layer containing a charge transporting substance as a main component is provided on a conductive support, and a charge transporting layer containing a charge generating substance and a silylated polyvinyl alcohol with a silylating agent, or a combination of the silylated polyvinyl alcohol and a crosslinking agent is provided on the conductive support. 1. A printing original plate for electrophotographic engraving, characterized in that a charge generation layer whose surface can be made hydrophilic is formed of a reactant.