JPH01114861A - Master plate for electrophotographic planographic printing - Google Patents

Abstract

PURPOSE:To improve the electrostatic characteristics of a printing plate and to eliminate the scumming of a copied image so that the sharp image is formed by using a specific binder resin for photoconductive layers. CONSTITUTION:The title master plate is formed by providing >=1 layers of the photoconductive layers contg. photoconductive zinc oxide and the binder resin on a conductive base. >=1 kinds of the resins having the substituents expressed by the formula I and/or II are used as the binder resin. In the formulas, R1, R3 denote H, aliphat. group; R2, R4 denote an aliphat. group, arom. group. For example, the homopolymer of the monomer having the above- mentioned substituent or the copolymer of said monomer and the other monomer (e.g.: the compd. expressed by the formula III) is usable for said resins. A desired dye may be added as a spectral sensitizer to the photoconductive layers.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an original plate for electrophotographic lithographic printing, and in particular, an original plate for electrophotographic lithographic printing that has improved electrostatic properties and does not cause any scumming. Regarding.

[Conventional technology]

As representative electrophotographic photoreceptors, there are photoreceptors having a photoconductive layer formed on a support and photoreceptors having an insulating layer on the surface, which are widely used.

Photoreceptors, consisting of a support and at least one photoconductive layer, are used for imaging by most common electrophotographic processes, ie, charging, imagewise exposure and development, and optionally transfer.

Furthermore, a method of using an electrophotographic photoreceptor as an offset original plate for da/r left plate making is widely used. Particularly in recent years, direct electrophotographic lithography has become important as a method for printing high-quality printed matter with a print count of several hundred to several dozen sheets.

To form the photoconductive layer of the electrophotographic photoreceptor (the binder used has excellent film-forming properties and dispersion ability of the photoconductive powder in the binder, and also It has good adhesion to the substrate, and the photoconductive layer of the recording layer has excellent charging ability, low dark decay, large light decay, and little pre-exposure fatigue. It is necessary to have various electrostatic properties such as stable properties and excellent imaging performance.

Examples of resins traditionally used as binders include silicone resin (Japanese Patent Publication No. 34-6670), styrene-citadiene resin (Japanese Patent Publication No. 35-1960), alkyd resins,
Maleic acid resin, polyamide (Special Publication No. 35-11219
), vinyl acetate resin (Japanese Patent Publication No. 41-2425), vinyl acetate copolymer (Japanese Patent Publication No. 41-2426), acrylic resin (Japanese Patent Publication No. 35-11216), acrylic ester copolymer (e.g. 35-11219, Japanese Patent Publication No. 36-8510, Japanese Patent Publication No. 41-13946, etc.) are known.

However, in electrophotographic photosensitive materials using these resins, 1) the affinity with the photoconductive powder is insufficient, resulting in poor dispersibility of the coating liquid, and 2) the charging property of the photoconductive layer is poor. low, 3
4) The quality of the image area of the copied image (halftone reproducibility and resolution) is poor; 4) The environment at the time of creating the copied image (e.g. high temperature and high humidity;
The problem was that the image quality was easily affected by low temperatures (low temperature, low humidity, etc.).

A number of methods have been proposed to improve the electrostatic properties of the photoconductive layer, and one such method is to use a compound containing a carboxyl group or a nitro group in an aromatic ring or a furan ring, or a dicarboxylic acid. A method of further combining anhydrides and making them coexist in the photoconductive layer is disclosed in Japanese Patent Publication No. 42-6878 and Japanese Patent Publication No. 45-3073. However, even the photosensitive materials improved by these methods do not have sufficient electrostatic properties, and none particularly have excellent light attenuation properties. Therefore, in order to improve the lack of sensitivity of this photosensitive material, a method of adding a large amount of sensitizing dye to the photoconductive layer has been conventionally used, but the photosensitive materials produced by this method have a remarkable whiteness. This has caused problems such as deterioration of the quality of the recording medium and, in some cases, deterioration of the dark decay of the photosensitive material, making it impossible to obtain a sufficient copy image.

On the other hand, JP-A-60-10254 discloses a method of adjusting the average molecular weight of a resin used as a binder resin for a photoconductive layer. That is, an acrylic resin with an acid value of 4 to 50 and an average molecular weight distribution of 103 to 1040;
A technique is described for improving electrostatic properties (particularly repeatability as an RPC photoreceptor), moisture resistance, etc. by using together components having a distribution of 0' to 2×10 5 .

Furthermore, research is being carried out on lithographic printing original plates using electrophotographic photoreceptors, and a binder resin for the photoconductive layer that has both the electrostatic properties of an electrophotographic photoreceptor and the printing properties of a printing original plate has been developed. For example, in Japanese Patent Publication No. 50-31011, My 1.8
03 to 10' and a Tg of 10 to 80°C, and a copolymer consisting of methocacrylate-based 7-maru and other monomers other than 7-maru, and JP-A-53-5
No. 4027 discloses a method using a terpolymer containing a (meth)acrylic acid ester having a substituent having a carboxylic acid group at least 7 atoms away from the ester bond; Kaisho 57-2o2544
This issue uses quaternary or penta-component copolymers containing acrylic acid and hydroxyethyl (meth)acrylate.
Furthermore, in JP-A No. 58-68046, a photoconductive material using a terpolymer containing a (meth)acrylic acid ester having an alkyl group having 6 to 12 carbon atoms as a substituent and a vinyl monomer containing a carboxylic acid is disclosed. It is described that it is effective in improving the desensitization property of the layer.

[Problem that the invention seeks to solve]

However, even if the resin is said to be effective in the electrostatic properties and moisture resistance properties mentioned above, when actually evaluated, it is found that the electrostatic properties such as chargeability, dark charge retention, photosensitivity, photoconductive layer, etc. There were problems with the smoothness, etc., and it was not practically satisfactory.

Furthermore, even when binder resins are said to have been developed as original plates for electrophotographic lithographic printing, when actually evaluated, there were problems with the electrostatic properties, background smearing of printed matter, and the like.

The present invention is intended to improve the problems of conventional electrophotographic photoreceptors as described above.

An object of the present invention is to provide a high-quality electrophotographic photoreceptor that has improved electrostatic properties (in terms of dark charge retention and photosensitivity) and reproduces copied images that are faithful to the original images.

Another object of the present invention is to provide an electrophotographic photoreceptor that produces clear, high-quality images even when the environment during copy image formation fluctuates, such as low temperature and low humidity, or high temperature and high humidity.

Another object of the present invention is to provide a lithographic printing plate that can be used as an electrophotographic lithographic printing original plate and can produce printed matter completely free from scumming.

Another object of the present invention is to provide an electrophotographic photoreceptor that is less affected by the type of sensitizing dye that can be used.

[Means for solving problems]

The above problem is solved in a lithographic printing original plate using an electrophotographic photoreceptor in which a photoconductive layer containing at least one photoconductive zinc oxide and a binder resin is provided on a conductive support. At least one of the binder resins has the following general formula (I
) and/or a substituent represented by the general formula (■).

General formula (I) -CONSO2-R2 General formula (I
t) -CONO8O2-R4 In the formula, R1, R
3 each represents a hydrogen atom or an aliphatic group, and R2 and R4 each represent an aliphatic group or an aromatic group.

To explain the general formula (I) and general formula (I[) in detail, preferably, in formula (I) U), R1, R3
are each a hydrogen atom or an optionally substituted alkyl group having 1 to 12 carbon atoms (e.g. methyl group, ethyl group, propyl group, butyl group, heptyl group, pentyl group, hexyl group,
octyl group, decyl group, 2-chloronityl L2-7' lomoethyl group, 2-methoxyethyl group, 3-chloropropyl group, 3-methoxypropyl group, etc.), optionally substituted aralkyl group having 7 to 12 carbon atoms ( For example, benzyl group, 7
enethyl group, 3-phenylpropyl group, methylbenzyl group, chlorobenzyl group, methoxybenzyl group, etc.).

R2 and R4 are each an optionally substituted alkyl group having 1 to 12 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group, dodecyl group, 4-chlorobutyl group, 4 -methoxybutyl group, 3-
Bromopropyl group, 6-)0 Mohexyl group, 6-methoxyethyl group, 4-methoxycarbonylbutyl group, 1
0-bromodecyl group, etc.], an optionally substituted aralkyl group having 7 to 12 carbon atoms (e.g. benzyl group, phenethyl group, 3-phenylpropyl group, methylbenzyl group, chlorobenzyl group, methoxybenzyl group, methoxycarbonylbenzyl group) groups] or aryl groups (e.g. phenyl groups, etc.) or aryl groups (e.g. phenyl groups,
naphthyl group, tolyl group, silyl group, mesityl group, methoxyphenyl group, chlorophenyl group, cyanophenyl group,
(methanesulfonylphenyl group, etc.) in Table bf.

The binder resin used in the present invention is a resin containing a substituent represented by the above general formula (I) and/or general formula (II). The weight average molecular weight of the binder resin is 10' to 5Xl
O'' range is preferred, more preferably 5
10' to 105.

The glass transition point of the resin is preferably in the range of -10°C to 100°C, more preferably in the range of -5°C to 80°C.

To obtain this resin, a synthetic resin is subjected to a polymer reaction to obtain the general formula (
I) and/or a method of introducing a substituent represented by general formula (II), and a method of polymerizing a monomer having a substituent represented by general formula (I) and/or general formula (II) to produce a polymer. There are two ways to obtain this, but the latter method is more practical. In the latter method, the monomer having the above-mentioned substituent can be polymerized alone, but it is also possible to copolymerize the monomer having the above-mentioned substituent with another monomer not having the above-mentioned substituent to form a copolymer. You can also take the method of obtaining , which is more practical.

When forming the copolymer, the content of the monomer having the substituent is preferably 1 to 15% by weight, more preferably 2 to 10% by weight.

The content of the monomer having the above-mentioned substituent is 15 in the total resin amount.
If the amount exceeds % by weight, the surface smoothness of the zinc oxide-containing photoconductive layer will become rough, and electrophotographic properties such as chargeability will also deteriorate. On the other hand, if it is less than 1% by weight, the desensitizing effect of the desensitizing treatment liquid will not be sufficient when used as an offset master original plate.

Specific examples of monomers having substituents represented by general formula (I) and/or general formula (If) are listed below.

However, the scope of the present invention is not limited thereto.

II II
II II
III II
II I+II
II II
11II II
II I+ In the copolymer, the acidic groups include -P03H group, -8o5H group and/or
or -COOH group-containing copolymer component from 0.05 to 5
It may be included in a weighted amount.

More specifically, a (meth)acrylic copolymer containing a total amount of 30% by weight or more of monomers represented by the following general formula (I[I) as a co-11 polymer component is used in the resin of the present invention. This can be cited as an example.

General formula (I[I) (1) In general formula (III), X represents a hydrogen atom, a halogen atom (for example, a chloro atom, a bromo atom), a 7-cya group, or an alkyl group having 1 to 4 carbon atoms. R1 is carbon number 1
~18 optionally substituted argyl groups (e.g. methyl group, ethyl group, propyl group, butyl group, pentyl group,
Hexyl group, octyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, 2-methoxyethyl group, 2
-ethoxyethyl group, etc.), an optionally substituted alkenyl group having 2 to 18 carbon atoms (e.g., vinyl group, allyl group,
isopropenyl group, butenyl group, hexenyl group, heptenyl group, octenyl group), optionally substituted aralkyl group having 7 to 12 carbon atoms (e.g. benzyl group, phenethyl group, methoxybenzyl group, ethoxybenzyl group, methylbenzyl group) groups), optionally substituted cycloalkyl groups having 5 to 8 carbon atoms (e.g. tJf, cyclopentyl groups,
cyclohexyl group, cycloheptyl group, etc.), aryl group (eg, phenyl group, tolyl group, xyl group, mesityl group, naphthyl group, methoxyphenyl group, ethoxyphenyl group, chlorophenyl group, dichlorophenyl group, etc.).

The above-mentioned "copolymer component containing an acidic group" may be any vinyl compound containing an acidic group that can be copolymerized with the general formula (III) (for example, according to the polymer data "Molecular Data Handbook [Basic Edition]" Baifukan (1986).Specifically, acrylic acid, α- and/or β-substituted acrylic acid (e.g. α-
Acetoxy form, α-acetoxymethyl form, α-(2-amino)methyl form, α-chloro form, α-bromo form, α-7
0 body, α-tributylsilyl body, α-cyano body, β-
chloro form, β-bromo form, α-chloro-β-methoxy form, α, β-dichloro form, etc.), methacrylic acid, itaconic acid, itaconic half-esters, itaconic half-amides, crotonic acid, 2-alkenyl Carboxylic acids (e.g. 2-pentenoic acid, 2-methyl-2-hexenoic acid, 2-octenoic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-octenoic acid, etc.), maleic acid, maleic acid half ester kind,
Half-ester derivatives of vinyl or allyl groups of maleic acid half-amides, vinylbenzenecarboxylic acid, vinylbenzenesulfonic acid, vinylsulfonic acid, vinylphosphonic acid, and dicarboxylic acids, and ester derivatives and amide derivatives of these carboxylic acids or sulfonic acids. Examples include compounds containing the acidic group in the substituent.

Furthermore, the binder resin used in the present invention includes a monomer having a substituent represented by the general formula (Il and/or general formula (II)), a monomer having the above-mentioned general formula (I[l), and Along with the monomer containing an acidic group, other monomers other than these may be contained as copolymerization components, such as Eva, α-olefins, vinyl alkanoates or allyl esters, acrylonitrile, methacrylonitrile, vinyl ethers,
Acrylamides, methacrylamides, styrenes,
Heterocyclic vinyls (eg, vinylpyrrolidone, vinylpyridine, vinylimidazole, vinylthiophene, vinylimidacillin, vinylpyrazole, vinyl-dioxane, vinylkyrin, vinylthiazole, vinyl-oxazine, etc.) and the like can be mentioned. Especially vinyl acetate, allyl acetate,
Acrylonitrile, methacrylonitrile, styrenes, etc. are preferred components from the viewpoint of improving film strength.

Conventionally known resins can be used in combination with the resin used in the present invention. For example, silicone resins, alkyd resins, vinyl acetate resins, polyester resins, styrene-butadiene resins, acrylic resins, etc.
968 Harumi Uemiyamoto; Hidehiko Takei, Imaging 1973
(N18) 9 and other known materials for the binder resin used in the photoconductive layer are cited.

Further, the photoreceptor using the resin of the present invention provides a copy image with clear image quality and no blurring even if the environment changes greatly from low temperature and low humidity to high temperature and high humidity. .

The total amount of binder resin used for the photoconductive zinc oxide is 10 to 100 parts by weight, preferably 15 to 50 parts by weight, per 100 parts by weight of the photoconductor.

In the present invention, each dye can be used in combination as a spectral sensitizer, if necessary. For example, Harumi Miyamoto; Hidehiko Takei, Imaging 1973 (m8) p. 12, C, J, Y
Oung et al., RCA Review 15.469 (
1954), Wataru Kiyota, Transactions of the Institute of Electrical Communication Engineers J63-
C (2), 97 (1980), Yujibe Harasaki, Industrial Chemistry Journal 66.78 and 188 (1963), Tadaaki Tani, Journal of the Photographic Society of Japan 35.208 (1972), etc. Carbonium-based dyes, diphenylmethane Pigments, triphenylmethane dyes, xanthine dyes, phthalein dyes,
Examples include polymethine dyes (for example, oxonol dyes, merocyanine dyes, cyanine dyes, rhodacyanine dyes, styryl dyes, etc.), phthalocyanine dyes (which may contain metal), and the like.

More specifically, examples using mainly carbonium dyes, triphenylmethane dyes, xanthine dyes, and phthalein dyes are disclosed in Japanese Patent Publication No. 51-452, Japanese Patent Application Publication No. 50-90334, and Japanese Patent Application Publication No. 50-90334. No. 50-114227,
JP 53-39130, JP 53-82353, U.S. Patent No. 3052540, U.S. Patent No. 40544
50, JP-A-57-16456, and the like.

oxonol dye, merocyanine dye, cyanine dye,
Polymethine dyes such as rhodacyanine dyes include F, M
, Hammer, “The Cyanine D.
yes andRe1ated Compounds
J. et al., and more specifically, U.S. Pat. No. 3,047,384 and U.S. Pat. No. 31,105.
No. 91, U.S. Patent No. 3,121,008, U.S. Patent No. 31
No. 25447, US Pat. No. 3,128,179, US Pat. No. 3,132,942, US Pat. No. 3,622,317, British Patent No. 1,226,892, British Patent No.
No., British Special Fraud No. 1405898, Special Publication No. 48-781
4, Japanese Patent Publication No. 55-18892, and the like.

Furthermore, as a polymethine dye that spectrally sensitizes the near-infrared to infrared light region with a long wavelength of 700 nm or more, JP-A-47-840
No., JP-A No. 47-44180, JP-A No. 51-4106
No. 1, JP-A-49-5034, JP-A-49-4512
No. 2, JP-A-57-46245, JP-A-56-351
No. 41, JP-A-57-157254, JP-A-61-2
No. 6044, JP-A No. 61-27551, U.S. Patent No. 3
No. 619154, U.S. Patent No. 4175956, “Re
5earch Disclosure@J 1982,
216, pp. 117-118.

The photoreceptor of the present invention is also excellent in that its performance does not easily vary depending on the sensitizing dye, even when various sensitizing dyes are used together.

Furthermore, if necessary, various conventionally known additives for electrophotographic photosensitive layers such as chemical sensitizers can be used in combination. For example, the review mentioned above: Imaging 1973 (81
8) Electron-accepting compounds (e.g., halogens, benzoquinone, cranyl, acid anhydrides, organic carboxylic acids, etc.) cited in the review on page 12, Hiroshi Komon et al., "Recent development and practical use of photoconductive materials and photoreceptors" Examples include polyarylalkane compounds, hindered phenol compounds, p-7 unilenediamine compounds, etc. cited in the review of Nippon Kagaku Information Publishing Department (1986), Chapters 4 to 6 of "Nihon Kagaku Information Publishing Department" (1986).

The amount of each of these rice additives added is not particularly limited, but is usually 0.0001 to 2.0 parts by weight per 100 parts by weight of the photoconductor.
Parts by weight.

The thickness of the photoconductive layer is preferably 1 to 100 microns, particularly 10 to 50 microns.

The photoconductive layer according to the invention can be provided on a conventionally known support. Generally speaking, the support of the electrophotographic photosensitive layer is preferably electrically conductive.As the electrically conductive support, for example, a base material such as metal, paper, or plastic sheet is impregnated with a low-resistance substance, just as in the conventional case. those that have been subjected to conductive treatment, such as those that have been coated with at least one layer for the purpose of imparting conductivity to the back surface of the substrate (the surface opposite to the surface on which the photosensitive layer is provided) and also to prevent curling, and those that have been coated with at least one layer for the purpose of preventing curling, etc. Those with a water-resistant adhesive layer on the surface of the body, those with at least one pre-coated layer provided as necessary on the surface layer of the support, and those with a conductive plastic substrate on which M, etc. is vapor-deposited, laminated on paper. can be used.

Specifically, examples of conductive substrates or conductive materials include:
Yukio Sakamoto, Electrophotography, 14, (1), pp. 2-11 (
1975), Hiroyuki Moriga, “Introductory Chemistry of Special Papers” Kobunshi Publishing (1975), M, F.

Hoover, J., Macromol, Sci., C.
hem, A-4 (61, pp. 1327-1417 (
1970) etc. are used.

〔Example〕

Embodiments of the present invention are illustrated below, but the content of the present invention is not limited thereto.

Synthesis example 1 Butyl methacrylate 90F, compound example of the present invention (4)
monomer 10f1 methacrylic acid 0.5F and toluene 2
After heating the mixed solution of 00f to a temperature of 75°C under a nitrogen stream, azobisisobutyronitrile 1. Add Of, 8
Allowed time to react. The weight average molecular weight of the obtained copolymer (I) was 4.3000, and the Gaussian transition point was 42°C.

Synthesis example 2 Butyl methacrylate 100F, methacrylic acid 0.5F
After heating a mixed solution of toluene 2002 to a temperature of 75°C under a nitrogen stream, azobisisobutyronitrile 1.0
2 was added and reacted for 8 hours. Obtained copolymer (It)
The weight average molecular weight of is 45,000, and the Gaussian transition point is 48°C.
Met.

Synthesis Example 3 Butyl methacrylate 90? A mixed solution of 10 f of 2-hydroxyethyl methacrylate, 0.52 g of methacrylic acid, and 200 t of toluene was heated to a temperature of 75° C. under a nitrogen stream, and then 1.0 g of azobisisobutyronitrile was added and reacted for 10 hours. The resulting copolymer (II[) had a weight average molecular weight of 42,000° and a Gaussian transition point of 43°C.

Synthesis example 4 Butyl methacrylate 802, compound example of the present invention (5)
A mixed solution of monomer 20f and toluene 200f was reacted under the same conditions as in Synthesis Example 1.

The weight average molecular weight of the obtained copolymer (N) was 43,000
, the Gaussian transition point was 40°C.

Example 1 Copolymer (I) produced in Synthesis Example 1 40 f (as solid content), zinc oxide 200? , Rose Bengal 0.
A mixture of 05 and toluene 3009 was dispersed in a ball mill for 2 hours to prepare a photosensitive layer-forming product, and this was applied to conductive-treated paper using a wire bar so that the dry coating weight was 22 t/-. Dry at ℃ for 1 minute. Then, the electrophotographic photoreceptor was prepared by leaving it for 24 hours in a dark place at 20° C. and 65% RH.

Comparative Example A A comparative example was prepared in the same manner as in Example 1 except that the copolymer (If) 40 f (as solid content) produced in Synthesis Example 2 was used instead of the copolymer (I) used in Example 1. Electrophotographic photoreceptor A was manufactured.

Comparative Example B The same procedure as Example 1 was carried out except that the copolymer (I [I) 40 f (as solid content) produced in Synthesis Example 3 was used instead of the copolymer (I) used in Example 1. A comparative electrophotographic photoreceptor B was manufactured.

The film properties (surface smoothness), electrostatic properties, imaging performance, and imaging performance of these photosensitive materials under environmental conditions of 30° C. and 80% RH were investigated. Furthermore, the desensitization properties of the photoconductive layer when these photosensitive materials are used as original plates for offset masters (represented by the contact angle of the photoconductive layer with water after desensitization treatment)
and printability (scumming, printing durability, etc.) were examined.

Imaging performance and printability were determined using fully automatic plate making ELP 404V (exposure and printing using Fuji Photo Film 11 and developer ELP-T).
The investigation was conducted using a lithographic printing plate obtained by developing an image and etching it with an etching processor using a desensitizing liquid ELP-E (the printing machine was a Hamadastar 5oosx manufactured by Hamadastar ■). (using a mold).

The above results are summarized in Table-1.

The implementation aspects of the evaluation items listed in Table-1 are as follows.

Note 1] Smoothness of photoconductive layer: The obtained photosensitive material was tested using a Peck smoothness tester (Kumagai Riko).
The smoothness (5) was measured under the condition of 1 air capacity.
ajcc) was measured.

Note 2) Electrostatic properties: After subjecting each photosensitive material to corona discharge at 6 KV for 20 seconds using a paper analyzer (Paper Analyzer 5P-428 model manufactured by Kawaguchi Electric) in a dark room at a temperature of 20°C and 65% RH. , left for 10 seconds, and the surface potential at this time is V.

was measured. Then, the potential V after being left in the dark for 60 seconds. was measured, and the retention of the potential after dark decaying for 60 seconds, that is, the dark decay retention rate (DRR (%)) was expressed as (
v7o/v,.

) xloo (%). After the surface of the photoconductive layer was charged to -400V by corona discharge, the surface of the photoconductive layer was irradiated with visible light at an illuminance of 2.0 lux to increase the surface potential (
Determine the time it takes for Vlo) to attenuate to 1/1O, and from this find the exposure amount E,/. Calculate (looks/seconds).

Note 3) Imaging properties: Copied images obtained by leaving each photosensitive material for one day and night under the following environmental conditions, and then making a plate using a fully automatic plate making machine ELP-404VC (manufactured by Fuji Photo Film) (Capri, image quality) was visually evaluated. The environmental conditions during imaging were 20°C, 65% RH (
I) and 30° C. 80% R) ((II).

Note 4) Contact angle with water: After passing each photosensitive material once through an etching processor to desensitize the surface of the photoconductive layer using a desensitizing treatment liquid Etp-EC (manufactured by Fuji Photo Film), distilled water 2
A water droplet of μt is placed on it, and the contact angle with the water formed is measured using a goniometer.

Note 5) Background stains on printed matter: After fully automatic plate making, each photosensitive material was plate-made using ELP404v (manufactured by Fuji Photo Film ■) to form a toner image, and desensitized under the same conditions as above (Note 3). was used as an offset master to print 500 sheets on high-quality paper using an offset printing machine (Hamada Star #Tomo Hamadas I-8008XW), and this was used as background smudge I for all printed matter.

For background stains on printed matter, dilute the desensitizing treatment liquid 5 times.
In addition, the test is carried out in the same manner as the background staining method described above, except that the dampening water used during printing is diluted twice.

In the case of ■, this corresponds to printing under stricter conditions than in the case of ■.

Note 6) Printing durability: Indicates the number of sheets that can be printed without causing background smudges in the non-image areas or problems with image quality in the image areas of printed matter when each photosensitive material is processed under the evaluation conditions for printing stains I in property 5) above. (The greater the number of prints, the better the printing durability.) Note 7) D, M, (image density): The maximum value is the toner image density of the solid area (can be measured with a Macbeth reflection densitometer) .

As shown in Table 1, in the photosensitive material of the present invention, the photoconductive layer had good smoothness and electrostatic properties, and the actual copied images had no ground blur and the quality of the copied images was clear.

The photosensitive materials of the present invention and Comparative Examples A and B had good photoconductive layer surface smoothness and electrostatic properties.

However, copied images in an environment of 30°C and 80% RH are
The image quality of the present invention and Comparative Example A was almost unchanged at room temperature and humidity, but the image quality of Comparative Example B was
, and fogging occurred in non-image areas.

Furthermore, the contact angle with water of each photosensitive material desensitized with a desensitizing liquid was small for the material of the present invention and Comparative Example B, and large at 15° or more for the material of Comparative Example A. (Usually, the smaller the contact angle value, the higher the hydrophilicity). Also, when printing these as a master plate for offset printing, a good one with no background smearing in the non-image area is
These were the plates of the present invention and Comparative Example B.

However, when printing was performed using the plate of Comparative Example B produced under high temperature and high humidity conditions, scumming occurred in the non-image areas of the printed matter from the beginning.

Furthermore, even after printing 10,000 copies of the plate of the present invention, the image quality of the printed matter was good and no scumming occurred.

From the above facts, the photosensitive material of the present invention was extremely excellent as a master plate for offset printing, satisfying electrophotographic properties and producing a large number of prints without background smudge.

Example 2 Copolymer (IV) produced in Synthesis Example (4) 20 f
(as solid content), [ethyl methacrylate/acrylic acid (99/'') weight composition ratio] using a mixture of copolymer 20t, zinc oxide 200f, rose bengal 0.05f, mhydrophthalic acid 0.02f and toluene 300F. Except for the above, an electrophotographic photoreceptor was produced in the same manner as in Example 1.The electrophotographic photoreceptor was prepared in the same manner as in Example 1 using a fully automatic plate making machine ELP404.
When the plate was made using V, the density of the obtained offset printing master plate was 1.0 or more, and the image quality was clear. Furthermore, when etching was performed and printed using a printing press, the printed matter after cane printing had no capri in the non-image area and the image was clear.

Furthermore, this photosensitive material was placed in an environment of (40°C, 80% RH).
After storage for a week, the same treatment as above was performed, but there was no difference at all from before aging.

Examples 3 to 9 Copolymer 20F of the present invention shown in Table 2 and [ethyl methacrylate/acrylic acid (99/J) weight composition ratio] Copolymer 2
An electrophotographic photoreceptor was produced in the same manner as in Example 2, except that 0F resin was used.

When these were plate-made using the same apparatus as in Example 1, the density of the obtained offset printing master plate was 0.9 or more and the image quality was clear. Furthermore, when etched and printed using a printing press, the printed matter after cane printing had clear image quality with no capri.

Further, this photosensitive material was left in an environment of (40° C., 80% RH) for 4 weeks and then subjected to the same treatment as above, but there was no change at all compared to before aging.

〔Effect of the invention〕

The electrophotographic lithographic printing original plate of the present invention has good surface smoothness and electrostatic properties on the surface of the photoconductive layer, has clear image quality of copied images, is free from blurring, and is insensitive to fat due to the desensitizing liquid. When treated with fat, the contact angle with water is small, the hydrophilicity is large, and background smear does not occur during printing.On the other hand, even when cane printing is performed, the image quality of the printed matter is good and no background smear occurs.

7. ,,,,<-.

Representative Patent Attorney (8107) Kiyotaka Sasaki (and 3 others)
given name)

Claims (1)

[Scope of Claims] A lithographic printing original plate using an electrophotographic photoreceptor comprising at least one photoconductive layer containing photoconductive zinc oxide and a binder resin provided on a conductive support, An original plate for electrophotographic lithographic printing, characterized in that at least one of the adhesive resins has at least one substituent represented by the following general formula (I) and/or general formula (II). General formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, R_1 and R_3 each represent a hydrogen atom or an aliphatic group,
R_2 and R_4 each represent an aliphatic group or an aromatic group.