JPH01169455A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the title body having the excellent electrostatic characteristic, antihumidity property and durability by incorporating a specified resin in a binding resin. CONSTITUTION:At least two kinds of the resins A and B are incorporated in the binding resin. Namely, the resin A is composed of the resin which has a weight average mol.wt. of 10<3>-3X10<4>, and bonds at least one kind of an acidic group selected from the group of -PO3H2, -SO3H and -COOH groups to the end of main chain of a polymer. And the resin B is composed of the resin which has the weight average mol.wt. of 10<4>-5X10<5>, and a larger pKa value than that of the acidic group contd. in the resin A used together with the resin B and contains a copolymer component contg. at least one kind of the acidic group selected from the group of -PO3H2, -SO3H and -COOH groups, etc. Thus, the electrophotographic sensitive material having the excellent electrostatic characteristic, antihumidity property and durability is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having excellent electrostatic properties, moisture resistance, and durability.

(Prior Art) Electrophotographic photoreceptors have various configurations in order to obtain predetermined characteristics or depending on the type of electrophotographic process to which they are applied.

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 a photoconductive layer of at least 1N 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 direct plate making is widely used.

The binder used to form the photoconductive layer of the electrophotographic photoreceptor has excellent film-forming properties itself and the ability to disperse photoconductive powder into the binder, and the formed recording layer The photoconductive layer of the recording layer has good adhesion to the substrate, and the photoconductive layer of the recording layer has excellent charging ability, has low dark decay, large light decay, and low pre-exposure fatigue, and is easily resistant to changes in humidity during imaging. It is necessary to have various electrostatic properties such as the need to stably maintain these properties and excellent imaging performance.

Examples of resins that have been known for a long time include silicone resin (Japanese Patent Publication No. 34-6670), styrene-butadiene resin (
(Japanese Patent Publication No. 35-1960), alkyd resin, maleic acid resin, polyamide (Japanese Patent Publication No. 11219-197), vinyl acetate resin (Japanese Patent Publication No. 2425-1977), vinyl acetate copolymer (Japanese Patent Publication No. 2426-197) ,acrylic resin(
(Japanese Patent Publication No. 35-11216), acrylic acid ester copolymers (e.g., Japanese Patent Publication No. 11219/1971, Japanese Patent Publication No. 36/1982)
No. 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
) The quality of the image area of the copied image (especially halftone reproducibility and resolution) is poor; 4) The environment at which the copied image was created (e.g. high temperature,
5) The film strength and adhesion of the photosensitive layer are not sufficient, especially when used as an offset master, the photosensitive layer may come off during offset printing, making it impossible to print a large number of sheets. , etc. There was one of the problems.

Various methods have been proposed to improve the electrostatic properties of the photoconductive layer, and one such method includes the use of a compound containing a carboxyl group or a nitro group in an aromatic ring or a furan ring, or a dicarboxylic acid anhydride. further combined,
A method of coexisting in the photoconductive layer is disclosed in Japanese Patent Publication No. 42-6878,
It is disclosed in Japanese Patent Publication No. 45-3073. However, even with the photosensitive materials improved by these methods, their electrostatic properties are still insufficient, and none particularly excellent in light attenuation properties has been obtained. 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 whiteness of the photosensitive materials produced by this method deteriorates significantly. However, there is a problem in that the quality of the recording medium deteriorates, and in some cases, the dark decay of the photosensitive material deteriorates, 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 a component with an average molecular weight distribution of 101 to 104;
A technique is described for improving electrostatic properties (particularly good repeatability as a ppc photoreceptor), moisture resistance, etc. by using together components having a distribution of 4 to 2 x 104.

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, a (meth)acrylate monomer and other monomers are copolymerized in the presence of fumaric acid.
A combination of a resin with a TglO~80''C at O' and a copolymer consisting of a (meth)acrylate monomer and a hexamer other than fumaric acid, and JP-A-53-5402
No. 7 uses a terpolymer containing a (meth)acrylic acid ester having a substituent having a carboxylic acid group separated from the ester bond by at least 7 atoms, and JP-A No. 54-20735, In JP-A No. 57-202544, a quaternary polymer containing acrylic acid and hydroxyethyl (meth)acrylate uses a quinary copolymer, and in JP-A No. 58-68046, an alkyl group having 6 to 12 carbon atoms is used. It is described that a ternary copolymer containing ethyl (meth)acrylate and a carboxylic acid-containing tonyl monomer having a substituent thereof is effective in improving the desensitization property of the photoconductive layer.

(Problems to be Solved by the Invention) However, even though the resins are said to be effective in the above-mentioned electrostatic properties, moisture resistance properties, and durability, when actually evaluated, they are found to have particularly poor chargeability and dark charge retention. There were problems with electrostatic properties such as photoresistivity, photosensitivity, smoothness of the photoconductive layer, etc., and it was not practically satisfactory.

Furthermore, even in the case of a binder resin which is said to have been developed as an original plate for electrophotographic lithographic printing, when actually evaluated, there were problems with the above-mentioned electrostatic properties, scumming of printed matter, etc.

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 (particularly dark charge retention and photosensitivity) and reproduces copied images that are faithful to original images.

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

Another object of the present invention is to provide an electrophotographic photoreceptor that is less susceptible to the effects of the types of aggravating dyes that can be used in combination.

Another object of the present invention is to provide an original plate for electrophotographic planographic printing.
A lithographic plate that has excellent electrostatic properties (particularly dark charge retention and photosensitivity), reproduces copied images that are faithful to the original, and does not cause not only uniform background smudges on the entire surface of printed matter but also dotted smudges. The purpose is to provide original printing plates.

(Means for Solving the Problems) The above-mentioned problems are solved in an electrophotographic photoreceptor having a photoconductive layer containing at least an inorganic photoconductive material and a binder, in which the binder resin is one of the following resins [A] and The problem is solved by the Mio electrophotographic photoreceptor, which is characterized by containing at least two types of resins [B].

(i) Resin [A]; has a weight average molecular weight of 103 to 3 x 104, and -P
(ii) Resin [B]; 10' to 5x -PO,H5-SO3H, which has a weight average molecular weight of 104 and a pKa larger than the pKa of the acidic group contained in the resin [A] used together.

The resin containing a copolymer component containing at least one acidic group selected from -C0OH and -P-OR (R represents a hydrocarbon group), that is, the binder resin provided in the present invention, A low-molecular-weight resin [A] that does not contain at least one of the above acidic groups in the side chain that connects to the polymer main chain, but only at the end of the main chain, and an acidic resin with a larger pKa than this resin [A]. It is composed of a high molecular weight resin (CB) containing a group as a side chain of a copolymerization component.

The range is 5 x 104 to 1.5 x 104, and the proportion of the acidic group in the polymer is 0.1 to 20 per unit weight part.
Weight percent is preferred.

The glass transition point of the resin [A] is preferably -10"C-1
00''C, more preferably -5°C to 80''C.

The weight average molecular weight of resin [B] is 3 x 104 to 2 x 10%
is preferred.

The acidic group contained in the polymer side chain of resin CB) is
] is preferably contained in a proportion of 0.05 to 5% by weight. Particularly preferred are the combinations and proportions of acidic groups shown in the table below.

Table-A The glass transition point of resin [B] is preferably 0°C to 120°C.
°C range, more preferably 0 °C to 100 °C.

More preferably the temperature is 10°C to 80°C.

The conventionally known acidic group-containing binder resins as mentioned above are mainly used for offset masters, and their molecular weight is large (for example, 5.
×104 or more), and these copolymers were random copolymers, and the acidic group-containing copolymer components were randomly present in the polymer main chain.

In contrast, the low molecular weight binder resin used in the present invention [
A] is a polymer in which acidic groups contained in the resin are bonded to the ends of the main chain, and this is combined with a high molecular weight conventional acidic group-containing resin.

In the present invention, the acidic group portion of the polymer terminal of the resin [A] adsorbs to the stoichiometric defects of the inorganic photoconductor, and since it is a low molecular weight substance, the coating property of the surface of the photoconductor is improved. This improves photoconductor trapping and improves humidity properties, while ensuring sufficient photoconductor dispersion and suppressing agglomeration.

Resin CB) shows a very weak interaction with the photoconductor particles compared to resin [A], has the function of gently covering the particles, and does not interfere with the function of resin [A]. [A] alone makes the mechanical strength of the photoconductive layer insufficient.

The content of terminal acidic groups in resin [A] is 0.0% per unit weight part. If it is less than 5% by weight, the initial potential will be low and sufficient image density will not be obtained.

On the other hand, if the content of the acidic group is more than 20% by weight, dispersibility decreases, film smoothness and high-temperature electrophotographic properties decrease, and background smear increases when used as an offset master, so it is preferable. do not have.

Furthermore, if the content of side chain acidic groups in the resin [B] exceeds 5% by weight, adsorption of the resin CB) to the conductor particles occurs, destroying the dispersion of the photoconductor and forming aggregates or precipitates. is formed, and the coating film cannot be formed, or even if a coating film is formed, the electrostatic properties of the photoconductor obtained may be significantly deteriorated, or the smoothness of the photoconductor surface may be deteriorated. This is not preferable because it becomes rough and the strength against mechanical wear deteriorates.

When a photoreceptor with a rough photoconductive layer surface is used as an original plate for electrophotographic lithographic printing, the dispersion state of the zinc oxide particles that are the photoconductor and the binder resin may not be appropriate, resulting in the presence of aggregates. Because a photoconductive layer is formed, the non-image area cannot be made uniformly and sufficiently hydrophilic even if it is desensitized using a fat-free treatment liquid, causing printing ink to adhere during printing, and as a result, the printed matter becomes non-stick. This causes background stains in the image area.

Furthermore, even when only the low molecular weight resin [A] in the present invention is used as the binder resin, the photoconductor and the binder resin can sufficiently adsorb and coat the particle surface, resulting in a smooth photoconductive layer. Although it is possible to obtain image quality that is good in terms of electrostatic properties and electrostatic properties and is free from background smearing, the film strength is still insufficient and satisfactory results cannot be obtained in terms of durability.

Only when the resin of the present invention is used, the adsorption and coating interaction between the inorganic photoconductor and the binder resin can be properly performed, and the film strength of the photoconductive layer can be maintained.

In the -P-OR group in resin [B], RH is more specifically, for example, an optionally substituted alkyl group having 1 to 12 carbon atoms (e.g. methyl group, ethyl group, propyl group, butyl group, hexyl group). group, octyl group, decyl group, dodecyl group, 2-chloroethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 3-methoxypropyl group, etc.), optionally substituted aralkyl group having 7 to 12 carbon atoms (e.g. benzyl group, phenethyl group, chlorobenzyl group, methoxybenzyl group, methylbenzyl group, etc.),
An optionally substituted alicyclic group having 5 to 8 carbon atoms (e.g., cyclopentyl group, cyclohexyl group, etc.) or an optionally substituted aryl group (e.g., phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group) , chlorophenyl group, methoxyphenyl group, etc.).

Resins [A] and CB) may be any conventionally known resins as long as they have the physical properties described above, such as polyester resins, modified epoxy resins, silicone resins, olefin resins, polycarbonate resins, and vinyl alkanoate resins. , allyl alkanoate resin, modified polyamide resin, phenol resin, fatty acid modified alkyd resin, acrylic resin, etc. are used.

More specifically, resins [A] and [B] are (meth)acrylic copolymers containing a total of 30% by weight or more of monomers represented by the following general formula (1) as copolymer components. Each can be cited as an example.

General formula (1) %Formula% In the general formula (1), X represents a hydrogen atom, a halogen atom (for example, a chloro atom, a bromo atom), a cyano group, or an alkyl group having 1 to 4 carbon atoms.

Ro is an optionally substituted alkyl group having 1 to 18 carbon atoms (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.), carbon number 2~
18 optionally substituted alkenyl groups (e.g. vinyl group, allyl group, isopropenyl group, butenyl group, hexenyl group, heptenyl group, octenyl group, etc.), carbon number 7
~12 optionally substituted aralkyl groups (e.g. benzyl group, phenethyl group, methoxybenzyl group, ethoxybenzyl group, methylbenzyl group, etc.), optionally substituted cycloalkyl groups having 5 to 8 carbon atoms (e.g. cyclopentyl group, cyclohexyl group, cycloheptyl group, etc.)
, represents an aryl group (eg, phenyl group, tolyl group, xyl group, mesityl group, naphthyl group, methoxyphenyl group, ethoxyphenyl group, chlorophenyl group, dichlorophenyl group, etc.).

Resin [A] may be synthesized in such a way that the acidic group is bonded to the end of the main chain of a copolymer made of these copolymerized components. Specifically, a method using a polymerization initiator containing the acidic group or a functional group that can be converted later into an acidic group, or a method using a polymerization initiator containing the acidic group or a functional group that can be later converted into an acidic group, or a method using a polymerization initiator containing the acidic group or a functional group that can be converted later into an acidic group It can be produced by a method using a transfer agent, a method using a combination of the above two, and a method in which the functional group is introduced by utilizing a termination reaction in an anionic polymerization method.

For example, P, Dreyfuss, R, P, Qui
rk, Encycle.

Po1ya+, Sc, i, Eng, 7. 551
(1987), V.

Percec, Appl, Po13n+, Sci
, 285. 95 (1985), P.F.
Rempp, E., Franta, Adv, Po.
lym.

Sci, 58. 1 (1984), Y. Yamas
Hita, J.

Appl, Polys, Sci, Appl,
Polym, Sy+wp, 36°193 (19
81), R, Asan+i, M, Takaki.

Makroo+o1. Chem, 5upp1.12
．． 163 (1985), etc., can be produced by the synthesis method cited in the review.

The "acidic group-containing copolymer component" in the resin [B] of the present invention may be any vinyl compound containing an acidic group that can be copolymerized with the general formula (1). can. For example, it is described in "Polymer Data Handbook [Basic Edition]" edited by the Society of Polymer Science and Technology, Baifukan (published in 1986). Specifically, acrylic acid, α and/or
or β-substituted acrylic acid (e.g. α-acetoxy form, α-
Acetoxymethyl form, α-(2-aminomethyl form, α-
Chloro form, α-bromo form, α-fluoro form, α-tributylsilyl form, α-cyano form, β-chloro form, β-bromo form, α-chloro-β-methoxy form, α, β-dichloro form, etc. ), methacrylic acid, i.

Taconic acid, itaconic acid half esters, itaconic acid half amides, crotonic acid, 2-alkenylcarboxylic 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 esters, maleic acid half amides, vinylbenzenecarboxylic acid, vinylbenzenesulfonic acid, vinylsulfone acid,
Examples include half ester derivatives of vinyl or allyl groups of vinyl phosphoric acid and dicarboxylic acids, ester derivatives of these carboxylic acids or sulfonic acids, and compounds containing the acidic group in a substituent of amide derivatives thereof.

Furthermore, the resins [A] and CB) of the present invention each contain the monomer of general formula (1) described above and the monomer containing an acidic group in the resin [B], as well as other monomers other than these. may be contained as a copolymerization component.

For example, α-olefins, vinyl alkanoates or allyl esters, acrylonitrile, methacrylnitrile, vinyl ethers, acrylamides, methacrylamides, styrenes, heterocyclic vinyls (e.g. vinylpyrrolidone, vinylpyridine, vinylimidazole, vinylthiophene) , vinylimidacilline, vinylpyrazole, vinyl-dioxane, vinylquinoline, vinylthiazole, vinyl-oxazine, etc.).

Furthermore, other resins can also be used in combination with the resins [A] and [B] of the present invention. Examples of such resins include alkyd resins, polybutyral resins, polyolefins, ethylene-vinyl acetate copolymers, styrene resins, styrene-butadiene resins, acrylate-butadiene resins, and vinyl alkanoate resins.

If the above-mentioned other resin exceeds 30% (weight ratio) of the total binder resin amount using the resin of the present invention, the effects of the present invention (especially improvement in electrostatic properties) will be lost.

The ratio of resin [A] and resin CB used in the present invention varies depending on the type, particle size, and surface condition of the inorganic photoconductive material used, but generally the ratio of resin [A] and resin [B] is used. is 5 to 80 to 95 to 20 (weight ratio), preferably 15 to 60 to 85 to 40 (weight ratio).

The ratio of the weight average molecular weights of resin [A] and resin CB) is preferably 1.2 or more, more preferably 2.0 or more.

Inorganic photoconductive materials used in the present invention include zinc oxide,
Examples include titanium oxide, zinc sulfide, cadmium sulfide, cadmium carbonate, zinc selenide, cadmium selenide, tellurium selenide, lead sulfide, and the like.

The total amount of binder resin used for the inorganic photoconductive material 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, various dyes can be used in combination as spectral sensitizers if necessary. For example, Harumi Miyamoto, Hidehiko Takei, Imaging 1973 (Na8) p. 12, C, J
, Young et al., RCA Review 15.
469 (1954), Wataru Kiyota, Proceedings of the Institute of Electrical Communication, Bungo J63-C (Nα2), 97 (1980), Yuji Harasaki et al., Industrial Chemistry Magazine Dandan 78 and 188 (1)
963), Tadaaki Tani 8 Journal of the Photographic Society of Japan 11.208 (1
972) Carbonium dyes, diphenylmethane dyes, triphenylmethane dyes, xanthine dyes, phthalein dyes, polymethine dyes (e.g.,
oxonol dye, merocyanine dye, cyanine dye,
logocyanine dyes, styryl dyes, etc.), phthalocyanine dyes (which may contain metals), and the like.

More specifically, examples of those mainly using carbonium dyes, triphenylmethane dyes, xanthine dyes, and phthalein dyes include Japanese Patent Publication No. 452/1983, Japanese Patent Application Laid-open No. 90334/1983, and Japanese Patent Application Laid-Open No. 50-90334. -114227, JP 53-39130, JP 53-82353,
U.S. Patent No. 3°052.540, U.S. Patent No. 4. 0
54. 450, JP-A-57-16456, and the like.

oxonol dye, merocyanine dye, cyanine dye,
Polymethine dyes such as logcyanine dyes include F,
M, Warmmer rThe Cyanine D
yes and Related Compounds
J. et al., and more specifically, U.S. Pat. No. 3.047.384, U.S. Pat.
No. 10,591, U.S. Patent No. 3,121,008, U.S. Patent No. 3°125.447, U.S. Patent No. 3,128
, 179, U.S. Patent No. 3,132.942, U.S. Patent No. 3,622.317, British Patent No. 1.226.8
92, British Patent No. 1,309,274, British Patent No. 1,405.898, Japanese Patent Publication No. 48-7814, 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-47-84
No. 0, JP-A No. 47-44180, JP-A No. 51-410
No. 61, JP-A-49-5034, JP-A-49-451
No. 22, JP-A-57-46245, JP-A-56-35
No. 141, JP-A-57-157254, JP-A-61-
No. 26044, JP-A No. 61-27551, U.S. Patent No. 3゜619.154, U.S. Patent No. 4,175.956
No., rResearch Disclosure J
1982, 216, pp. 117-11B. The photoreceptor of the present invention is excellent in that even when various sensitizing dyes are used in combination, its performance does not easily change due to the sensitizing dye. Furthermore, if necessary, various conventionally known additives for electrophotographic photosensitive layers such as chemical sensitizers can be used in combination. For example, the above-mentioned review: Imaging 1973 (Nα8) p. ``Development and practical application of conductive materials and photoreceptors'' Chapters 4 to 6
Examples include polyarylalkane compounds, hindered phenol compounds, p-phenylenediamine compounds, etc. cited in the review of Chapter: Nihon Kagaku Information Co., Ltd. Publishing Department (1986).

The amount of these various additives added is not particularly limited, but
Usually O1'0001-2 per 100 parts by weight of photoconductor
．． It is 0 parts by weight.

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

In addition, when a photoconductive layer is used as a charge generation layer in a laminated photoreceptor consisting of a charge generation layer and a charge transport layer, the thickness of the charge generation layer is 0.01 to 1μ, particularly 0.05 to 0.5μ. suitable.

In some cases, an insulating layer is added mainly for the purpose of protecting the photoreceptor, improving its durability, dark decay characteristics, etc.

At this time, the insulating layer is set to be relatively thin, and when the photoreceptor is used for a specific electrophotographic process, the insulating layer provided is set to be relatively thick.

In the latter case, the thickness of the insulating layer is between 5 and 70μ, in particular 1
It is set to 0 to 50μ.

Charge transport materials for the laminated photoreceptor include polyvinylcarbazole, oxazole dyes, pyrazoline dyes, triphenylmethane dyes, and the like.

The thickness of the charge transport layer is 5 to 40 μm, particularly 10 to 3 μm.
0μ is suitable.

Typical resins used to form the insulating layer or charge transport layer include polystyrene resin, polyester resin, cellulose resin, polyether resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride vinyl oxide copolymer resin, Thermoplastic resins and curable resins such as polyacrylic resins, polyolefin resins, urethane resins, polyester resins, epoxy resins, melamine resins, and silicone resins are used as appropriate.

The photoconductive layer according to the invention can be provided on a conventionally known support. Generally speaking, the support for 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 impregnated with a low-resistance substance is used in the same manner as in the past. At least 11! ! Those coated with the above, those provided with a water-resistant adhesive layer on the surface of the support, those provided with at least one or more pre-coated layer as necessary on the surface layer of the support, those coated with A2, etc. A base material such as a conductive plastic laminated on paper can be used.

Specifically, examples of conductive substrates or conductive materials include:
Yukio Sakamoto, electronic photography, 14. (kl).

p2-11 (1975), Hiroyuki Moriga, "Introductory chemistry of special paper" Kobunshi Publishing (1975), M, P.

1(oover, J, Macromol, Set
, Chet A-4(6) r No. 1327-141
7 (1970) etc. is used.

(Example) Although embodiments of the present invention are illustrated below, the content of the present invention is not limited thereto.

Example 1 and Comparative Examples A-C (Synthesis Example 1) A mixed solution of 95 g of ethyl acrylate, 200 g of toluene and 50 g of isopropyl alcohol was heated for 85 minutes under a nitrogen stream.
After humidification to a temperature of °C, 4,4'-azobis(4-cyanovaleric acid) (hereinafter abbreviated as A).

B, C0V) was added and reacted for 10 hours.

The weight average molecular weight of the obtained copolymer (A-1) was 8.6
00, the glass transition point was 46°C.

(Synthesis Example 2) After heating a mixed solution of 95 g of ethyl methacrylate, 5 g of acrylic acid, and 200 g of toluene to a temperature of 90°C under a nitrogen stream, 2,2'-azobis(2,4-dimethylvaleronitrile) ) was added and reacted for 10 hours. The weight average molecular weight of the obtained copolymer (A-2) was 7800,
The glass transition point was 45°C.

(Synthesis Example 3) 98 g of ethyl methacrylate, 2 g of monomer of the following structure [A], 200 g of toluene, and 3 g of isopropyl alcohol
After heating 0 g of the mixed solution to a temperature of 85° C. under a nitrogen stream, 2.0 g of 2,2'-azobis(1-cyclohexanecarbonitrile) was added and reacted for 10 hours. The weight average molecular weight of the obtained copolymer (B-1) was 54,000.
The glass transition point was 48°C.

CH.

Structure [A] (Synthesis Example 4) A mixed solution of 97 g of ethyl methacrylate, 3 g of acrylic acid, and 200 g of toluene was reacted under the same conditions as in Synthesis Example 3 to obtain a copolymer (B-2) with a weight average molecular weight of 5oooo. Ta. The glass transition point was 48°C.

Example 1 8 g (solid content) of copolymer (A-1) produced in Synthesis Example 1, 3 g of copolymer (B-1) produced in Synthesis Example 3
2g (as solid content), 200g zinc oxide, 0.03g tetrabromophenol.

Rose Bengal 0.03g, maleic anhydride 0゜05
A mixture of g and 300 g of toluene was dispersed in a ball mill for 2 hours to prepare a photosensitive layer-forming product, and this was applied to conductive-treated paper with a wire bar so that the dry adhesion amount was 25 g/bo. Dry at ℃ for 1 minute. Next, an electrophotographic window illuminator was produced by leaving it in a dark place for 24 hours at 20° C. and 165% RH.

Comparative Example A Except for using only 40 g (as solid content) of the copolymer (A-1) produced in Synthesis Example 1 instead of the binder resins (A-1) and (B-1) used in Example 1. Comparative electrophotographic photoreceptor A was manufactured in the same manner as in Example 1.

Comparative Example B Instead of the binder resins (A-1) and (B-1) used in Example 1, 40 g (in terms of solid content) of only the copolymer (B-2) produced in Synthesis Example 4 was added. Comparative electrophotographic photoreceptor B was manufactured in the same manner as in Example 1 except for using the following.

Comparative Example C Copolymer (A-2) produced in Synthesis Example (2) was used instead of binder resins (A-1) and (B-1) used in Example 1.
A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that 8 g (as a solid content) and 32 g (as a solid content) of the copolymer (B-2) produced in Synthesis Example (4) were used. C was produced.

The eyelid properties (surface smoothness), electrostatic properties, imaging properties, and environmental conditions of these photosensitive materials were set to 30° C., 280% R)I, and the imaging bodies were investigated.

Furthermore, when these photosensitive materials are used as an original plate for off-set mask A, the desensitization property of the photoconductive layer (represented by the contact angle with water of the photoconductive layer after desensitization treatment) and the printability ( Background stains, printing durability, etc.) were investigated.

For the imaging side and printability, exposure and
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 Hamadastar 800SX manufactured by Hamadastar ■). (using a mold).

The above results are summarized in Table-1.

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 Beck smoothness tester (Kumagai Riko ■
The smoothness (
sec/cc) was measured.

Note 2) Electrostatic properties: In a dark room at a temperature of 20°C and 165% RH, each photosensitive material was subjected to corona discharge at 6 kV for 20 seconds using a paper analyzer (Paper Analyzer 5P-428 model manufactured by Kawaguchi Denki ■). Leave it for 10 seconds, and at this time the surface potential v1
° was measured. Then, the potential was left undisturbed for 60 seconds in the dark. The retention of the potential after dark decaying for 60 seconds, that is, the dark decay retention rate [DRR (%)] is determined by (
V'l. /V+o)X1.00 (%).

Further, 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 until the surface potential (V+) attenuated to 1/1O. , and calculate the exposure amount E, 7.0 (lux seconds) from this time.

Note 3) Imaging properties: After leaving each photosensitive material for one day and night under the following environmental conditions, fully automatic plate making machine ELP-404V (manufactured by Fuji Photo Film ■) was used.
The copied image (fogging, image quality) obtained by plate making was visually evaluated. Environmental conditions during imaging were 20°C, 65% R.
H(I) and 30°C 80% RH(n).

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

Note 5) Background stains on printed matter: Each photosensitive material is plate-made using a fully automatic plate-making machine ELP-404V (manufactured by Fuji Photo Film ■) to form a toner image, and the above (
After applying the fat-free treatment under the same conditions as Note 3), print 500 sheets on high-quality paper using an offset printing machine (Hamadaster soos . This is referred to as background smear I on printed matter.

For background stains on printed matter, dilute the fat-free treatment liquid 5 times.
In addition, the test was carried out in the same manner as the above-mentioned scumming (2), except that the dampening water used during printing was diluted twice.

H corresponds to printing under stricter conditions than ■.

Note 6) Printing durability: Indicates the number of sheets that can be printed without causing background stains in non-image areas or problems with image quality in image areas of printed matter when each photosensitive material is processed under the evaluation conditions for printing smear I in property 5) above. (The greater the number of prints, the better the printing durability.) As shown in Table 1, the photosensitive material of the present invention has good smoothness and electrostatic properties of the photoconductive layer, and is suitable for actual copying. There was no blurring in the image, and the quality of the copy was clear.

This means that the photoconductor and the binder resin are sufficiently adsorbed, and
This is presumed to be due to the fact that while the particle surfaces are coated, the interaction between the binders is also sufficiently maintained. For the same reason, even when used as an offset master original, the desensitization treatment with the desensitization treatment liquid progresses sufficiently, and the contact angle with water in the non-image area is as small as 15 degrees or less.
It can be seen that it is sufficiently hydrophilized. When actually printing and observing the background smear on the printed matter, no background smudge was observed, and it was found that the number of printed sheets exceeded 10,000. Comparative examples A and C
The number of printed sheets was lower than that of the photosensitive material of the present invention. Furthermore, Comparative Example C has electrophotographic properties of D, R
, R, deteriorated compared to the material of the present invention.

In Comparative Example B, the smoothness of the photoconductive layer was extremely poor, the electrophotographic properties were also deteriorated, and the quality of the copied image was also deteriorated. Also, when used as an offset master, there was large variation in hydrophilization of non-image areas, and background stains occurred on printed matter from the beginning of printing.

As a result of the above, an electrophotographic material satisfying electrostatic properties and suitability for printing can be obtained only when the resin of the present invention is used.

Example 2 95 g of ethyl methacrylate 5 g of thioglycolic acid,
200g toluene and 100g isopropyl alcohol
After heating the mixed solution to a temperature of 75°C under a nitrogen stream,
1.0 g of azobisisobutyronitrile was added and reacted for 8 hours. The weight average molecular weight of the obtained copolymer (A-3) was 7800, and the glass transition point was 46°C.

Instead of copolymers (A-1) and (B-1) used in Example 1, 10 g (as solid content) of copolymer (A-3) and copolymer (B) of Synthesis Example (3) were used. -1) Each photoreceptor was manufactured in the same manner as in Example 1, except that 30 g (in terms of solid content) was used, and each characteristic was measured in the same manner as in Example 1. The surface smoothness of the photoconductive layer of each photoreceptor is 80 (sec/
cc) and smooth. ■. ;-550V, D, R, R
.

96%, El/1113. 5 (lux, 5ec), and the image quality was good even in an environment of (38° C. 180% RH).

All of the photosensitive materials of the present invention have excellent chargeability, dark charge retention, and photosensitivity, and the actual reproduced images are produced at high temperatures (30°C, 18°C).
Even under the harsh conditions of 0% RH), clear images were produced without any occurrence of ground blur or fine line skipping.

Furthermore, after making a plate in the same manner as in Example 1, printed matter with clear image quality and no background smudge was obtained even when printed as an offset master original plate and after printing 10,000 sheets.

Examples 3 to 6 Each copolymer was synthesized under the same conditions as in Example 2, except that the thioglycolic acid used in Example 2 was replaced with the compound shown in Table 2.

Table-2 Instead of copolymers (A-1) and (B-1) used in Example 1, 10 g each of copolymers A-4 to A-7 (as solid content) and Synthesis Example 3 were used. Copolymer (B-1) 3
Each phosphor was manufactured in the same manner as in Example 1, except that 0 g (in terms of solid content) was used, and each property was measured in the same manner as in Example 1.

All of the photosensitive materials of the present invention have excellent chargeability, dark charge retention, and photosensitivity, and the actual reproduced images are produced at high temperatures (30°C, 18°C).
Even under the harsh conditions of 0% RH), clear images were produced without any occurrence of ground pressure or fine line skipping. Furthermore, when printing was performed using the offset master original plate, the image quality of the printed matter after printing 10,000 sheets was clear and free of background stains.

Examples 7 to 12 The copolymers shown in Table 3 were synthesized as the resin [B) of the present invention.

Table-3 Resin [A] of Table-2 and resin [B] of Table-3 were mixed (1/3
) Each photosensitive material was prepared in the same manner as in Example 1 except that the weight ratios were used as shown in Table 4. Furthermore, electrostatic properties were measured in the same manner as in Example 1. Table the results.
4.

All of the photosensitive materials of the present invention have excellent chargeability, dark charge retention, and photosensitivity, and the actual reproduced images are also produced at high temperatures and high humidity (30'C, 80°C).
Even under the harsh conditions of 0% RH), it provided clear images with no occurrence of ground blur or fine line skipping.

Furthermore, after making a plate in the same manner as in Example 1, printed matter with clear image quality and no background smudge was obtained even when printed as an offset master original plate and after printing 10,000 sheets.

Example 13 95 g of benzyl methacrylate) and 200 g of toluene
After heating the mixed solution to a temperature of 95°C under a nitrogen stream,
2. 2'-Azobis(4-cyanoheptator) 5g
was added and reacted for 8 hours. After the temperature was further raised to 85° C., 1.2 g of succinic anhydride and pyridine Ig were added and reacted for 10 hours. The weight average molecular weight of the obtained copolymer (A-8) was 8°500, and the glass transition point was 38°C.

A photosensitive material was produced in the same manner as in Example 2, except that 10 g of copolymer (A-8) was used instead of copolymer (A-3).

Each characteristic was measured in the same manner as in Example 1.

All of the photosensitive materials of the present invention have excellent chargeability, dark charge retention, and photosensitivity, and the actual reproduced images are also produced at high temperatures (30°C, 80°C).
Even under severe conditions (%RH), it provided clear images with no occurrence of ground blur or fine line skipping. Furthermore, when printing was performed using the offset master original plate, the image quality of the printed matter after printing 10,000 sheets was clear and free of background stains.

The photosensitive material of the present invention has excellent chargeability, dark charge retention, and photosensitivity, and the actual copied images are also high temperature (30°C, 180% RH).
) Even under the harshest conditions, it provided clear images with no occurrence of ground braking or skipping of thin lines.

Furthermore, after making a plate in the same manner as in Example 1, printed matter with clear image quality and no background smudge was obtained even when printed as an offset master original plate and after printing 10,000 sheets.

Example 14 A mixed solution of 94 g of n-propyl methacrylate, 6 g of 2-aminoethanethiol, 100 g of isopropyl alcohol, and 200 g of tetrahydrofuran was heated under a nitrogen stream for 7 hours.
After heating to a temperature of 5°C, 1.0 g of azobisisoprodylonitrile was added and reacted for 8 hours. After cooling, it was reprecipitated into water 21 to precipitate the reaction product. After decanting the solvent, it was dried under reduced pressure at a temperature of 40°C.

The obtained copolymer was dissolved in 200 g of toluene and the temperature was raised to 9.
After the temperature was lowered to 0°C, 1.3 g of maleic anhydride and 1 g of pyridine were added, and the mixture was stirred for 10 hours to react. The weight average molecular weight of the obtained copolymer (A-9) was 6.200, and the glass transition point was 35°C.

Instead of copolymers (A-1) and (B-1) used in Example 1, 10 g (as solid content) of copolymer (A-9) and copolymer (B) of Synthesis Example (3) were used. -1) Each photoreceptor was manufactured in the same manner as in Example 1, except that 30 g (in terms of solid content) was used, and each characteristic was measured in the same manner as in Example 1.

Example 15 and Comparative Example D After heating a mixed solution of 48.5 g of ethylene mesotaphrylate, 45.5 g of benzyl methacrylate, 4.0 g of thioglycolic acid, and 200 g of toluene to a temperature of 90°C under a nitrogen stream, A , B, C.

V Ig was added and reacted for 8 hours.

The weight average molecular weight of the obtained copolymer (A-10) was 8,
The 300 glass transition temperature was 43°C.

8 g of the thus obtained copolymer (as solid content), 32 g of copolymer (B-1) of Synthesis Example (3), 200 g of zinc oxide, and 0.02 g of heptamethine cyanine dye represented by the following structural formula. A mixture of 0.05 g of phthalic anhydride and 300 g of toluene was dispersed in a ball mill for 2 hours to prepare a photosensitive layer. An electrophotographic photoreceptor was produced in the same manner as in Example 1 (Example 15) (cyanine dye) On the other hand, 48.5 g of ethyl methacrylate, 43.5 g of benzyl methacrylate, 5 g of methacrylic acid and 200 g of toluene were prepared. After the mixed solution was heated to a temperature of 100°C under a nitrogen stream, 6.0 g of azobisisobutyronitrile was added and reacted for 8 hours.

The weight average molecular weight of the copolymer thus obtained was 8.
,000, and the glass transition point was 43°C.

This resin was used as the copolymer (A-10) in Example (15).
), and a photoreceptor was produced in the same manner as in Example 10 (Comparative Example D).

The electrostatic properties of these photosensitive materials were measured using a paper analyzer in the same manner as in Example 1. However, a gallium-aluminum-arsenic semiconductor laser (oscillation wavelength: 780 nm) was used as a light source. The results are shown in Table-5.

Table-5 Comparative example C is compared to the above-mentioned comparative example C, R, R.

is getting worse. This shows that conventionally known resins have the problem of being extremely susceptible to the effects of the type of spectral sensitizing dye used in combination. In contrast, the binder resin of the present invention can be used even if the chemical structure of the spectral sensitizing dye changes significantly.
The object of the present invention is to provide a photosensitive material that has excellent chargeability, dark charge retention, and light intensity.

(Effects of the Invention) According to the present invention, an electrophotographic photosensitive material having excellent performance in terms of smoothness and strength of a photoconductive layer, electrostatic properties, imaging performance, as well as background smearing and rigidity resistance of printed matter can be obtained. can get.

Further, the electrophotographic light-sensitive material of the present invention can have excellent smoothness, electrostatic properties, etc. of the photoconductive layer even when used in combination with various aggravating dyes.

Procedural amendment September 70, 1986

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor having a photoconductive layer containing at least an inorganic photoconductive material and a binder, wherein the binder resin contains at least two of the following resins [A] and resin [B]. An electrophotographic photoreceptor comprising: (i) Resin [A]; A polymer having a weight average molecular weight of 10^3 to 3 x 10^4 and containing at least one acidic group selected from -PO_3H group, -SO_3H group and -COOH group. Resin bonded to the end of the main chain (ii) Resin [B]; has a weight average molecular weight of 10^4 to 5 x 10^5, and pKa of the acidic group contained in the resin [A] used together -PO_3H, -SO_3H, - with larger pKa
Resin containing a copolymer component containing at least one acidic group selected from COOH and ▲Mathematical formulas, chemical formulas, tables, etc.▼ (R represents a hydrocarbon group)