JPS62251756A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the wear resistance by short-time curing at a low temp. by forming a specified protective layer. CONSTITUTION:A protectibe layer contg. a cured film contg. a butyl etherified melamine-formaldehyde resin having <=1,500 number average mol. wt., 2-4 formaldehyde groups and 1-2 methylol groups bonded to one melamine uncleus and a fluororesin having 5-100 hydroxyl value and cong. F in the side chain if formed on the surface of a photosensitive layer. Thus, the wear resistance of the resulting sensitive body is improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electrophotographic photoreceptor having excellent durability.

(Prior Art) In an electrophotographic photoreceptor that uses a photoconductive substance as a photosensitive material, conventional photoconductive substances are used as photoconductive substances.

Inorganic photoconductive materials such as selenium, zinc oxide, titanium oxide, and cadmium sulfide have been mainly used.

However, many of these are generally highly toxic and there are problems in how to dispose of them.

On the other hand, the use of organic phototetraelectric compounds is generally less toxic than the use of inorganic photoconductive substances, and is also advantageous in terms of transparency, ease of handling, light weight, cost, etc. It has been widely studied recently.

When a 1f4A photoreceptor using an organic photoconductive compound is applied to an electrophotographic device using the Carlson method, an electrostatic m1 image is first formed on the surface of the photoreceptor, and the 1f4A photoreceptor is charged with the opposite sign and is generally called a toner. Transfer the toner image to another substrate 1, such as paper, using a developer.

It is fixed and you can get a copy. At this time, it is necessary to remove (clean) the slight amount of toner remaining on the surface of the photoreceptor using a bluff, blade, or the like.

By repeating the steps of development, rolling, and cleaning in this manner, the surface of the photoreceptor is worn, and as a result, the transferred image 1f becomes unclear.

In some cases, peeling of the photosensitive layer occurs, which significantly shortens the life of the photoreceptor. Due to these problems, photoreceptors are required to have strong durability.

Therefore, in order to improve the durability, JP-A-52-7692
It has been proposed to provide a protective layer on the surface as disclosed in Japanese Patent Application Laid-open No. 8 and Japanese Patent Application Laid-open No. 17732/1983.

(Problems to be Solved by the Invention) However, when a thermoplastic resin is used as in the conventional lfI layer, the abrasion resistance effect is not sufficient, and when a thermosetting resin is used, the retention layer Since formation requires high temperatures and a long period of time, the material of the underlying photosensitive layer deteriorates due to heat during that time, resulting in a decrease in electrophotographic properties.

Therefore, there is a need for a thermosetting protective layer material that has as high abrasion resistance as possible under low-temperature, short-time curing conditions.

(Means for Solving the Problems) The present invention solves the above problems by providing a specific protective layer.

That is, in the present invention, the number average molecular number is 1 on the surface of the photosensitive layer.
．． 500 or more, the number of formaldehydes bound per melamine nucleus is 2 to 4, and the number of methylol groups is 1 to 2.
a butyl etherified melamine/formaldehyde resin fA) having a hydroxyl value of 5 to 100 and a fluorine-containing resin having a fluorine atom in the polymer side chain (81) as a component; Related to electrophotographic photoreceptors.

The materials used in the electrophotographic photoreceptor of the present invention will be described in detail below.

The electrophotographic photoreceptor of the present invention is obtained by sequentially laminating a photosensitive layer and a protective layer on the conductive layer.

The conductive layer referred to herein is a conductive body such as paper or plastic film subjected to conductivity treatment, a plastic film laminated with metal foil such as aluminum, or a plate or drum of conductive metal such as aluminum.

Next, the photosensitive layer basically separates the functions of charge generation and transport, and includes a composite photoconductive layer that has a charge generation layer and a charge transport layer, and a single layer photoconductive layer that does not have such functional separation. be.

First, the composite photoconductive layer will be explained.

The charge generation layer contains an organic pigment that generates charges.

The organic pigments include azoxybenzene-based, disazo-based, trisazo-based, benzimidazole-based, polycyclic quinoline-based, indigoid-based, quinacridone-based, phthalocyanine-based, and perylene-based.

Pigments that generate charges, such as methine-based pigments, can be used.

These pigments are 9, for example, JP-A No. 47-37453;
% Japanese Patent Application Publication No. 47-37544, Japanese Patent Application Publication No. 18543-1970, Japanese Patent Application Publication No. 47-18544, Japanese Patent Application Publication No. 48-43942
No., JP-A-48-70538, JP-A-49-1231
No. 9% published No. 105536/1989, 752/1983
No. 14, Japanese Unexamined Patent Publication No. 50-92738, etc.

In particular, the
', η, and a' type gold metal phthalocyanines have high sensitivity even to long wavelengths, and are also effective as electrophotographic photoreceptors for printers equipped with diode lasers. Any organic pigment that generates charge carriers upon irradiation with such light may be used.

(9) A binder and/or plasticizer, and a fluidity imparting agent commonly used in electrophotographic photoreceptors are added to the charge generation layer.

Additives such as pinhole suppressants can be included as necessary. Binders include silicone resin, polyamide resin, polyurethane resin, polyester resin, epoxy resin, and polyketone resin.

Examples include polycarbonate resin, polystyrene resin, polymethyl methacrylate resin, polyacrylamide resin, and the like. Heat and/or photocurable resins can also be used.

In any case, there is no particular restriction as long as the resin is electrically insulating and can form a film under normal conditions. The binder is used in the charge generating layer in an amount of up to 300% by weight based on the organic pigment.

If it exceeds 30°O weight t%, the electrophotographic properties will deteriorate.

Examples of the plasticizer include halogenated paraffin, dimethylnaphthalene, and dibutyl phthalate. Examples of the fluidity imparting agent include Mogflo (manufactured by Monosanto Cal Co., Ltd.), and examples of the pinhole suppressor include benzoin, dimethyl tucrate, and the like. It is preferable to use each of these additives in an amount of 5% by weight or less based on the above-mentioned A-4a face and T+.

The charge transport j~ includes the '1 caustic transporting substance.

Examples of the charge transport substance include 3-phenylcarbazole, 2-phenylindole, oxadiazole, oxatriazole, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)
Pyrazoline, 2-phenyl-4-(4-diethylaminophenyl)-5-phenyloxazole, triphenylamine, imidazole, 2,7-sinitro 9-fluorenone.

2, 4.7-1-Rini!・Rho9-fluorenone, 4H
-indeno(1,2,6)thiophen-4-one, 1-
Bromopyrene, 2-phenylpyrene, Bo! J-N-
Vinylcarbazole, polyvinylpyrene, polyvinylbenzothiophene, polyvinylanthracene.

These include polyvinylpyrazoline, etc., and derivatives thereof.

The charge transport layer may also contain C, if necessary, with additives such as a binder, a plasticizer, a fluidity imparting agent, and a pinhole inhibitor similar to those in the charge generation layer. Binders are charge-transporting substances! ! 5. 400% weight to avoid deterioration of photographic properties
More than F is preferable, and less than I! - Regarding the charge transporting substance, it is preferably 0% by weight or less in terms of film properties. Each of the above additives is preferably present in an amount of 5 tons If% or more based on the charge transporting substance.

The composite photoconductive layer may be one in which a charge generation layer and a charge transport layer are laminated in sequence, or conversely, a charge transport layer and a charge generation layer may be laminated in sequence. Also.

It may also have a sandwich structure in which a charge generation layer is sandwiched between two charge transport layers.

The thickness of the charge generation layer is preferably 0.001 to 10 μm, and preferably 0.2 to 5 μm. The thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 8 to 20 μm. If the thickness of the charge generation layer is less than 0.001 μm, the sensitivity tends to be poor, and if it exceeds 10 μm, the residual potential tends to increase. Furthermore, if the thickness of the charge transport layer is less than 5 μm, the charging property tends to be poor, and if it exceeds 50 μm, the sensitivity tends to decrease.

As a method for forming the charge-generating j-, when only the organic pigment mentioned above is used, it can be carried out by vacuum evaporation, and the organic pigment, binder, and optionally additives are added to acetone, methyl ethyl ketone, tetrahydrofuran, toluene, quinoa, etc.
It can also be formed by uniformly dissolving or dispersing it in a solvent such as methylene chloride or olethane, then coating and drying.

When forming a charge transport layer, a charge transport substance, a binder, and additives as necessary are uniformly dissolved or dispersed in the same solvent as for the charge generation layer, and then applied and dried. It can be formed by

Next, the single-layer photoconductive layer will be explained.

The single-layer photoconductive layer contains a charge-generating material or a charge-generating material and a charge-transporting substance. The charge-generating material can be the organic pigment used in the charge-generating layer, and the charge-transporting substance can be the same as the charge-transporting substance used in the AfJ charge-transporting layer.

In addition to these, the single-layer photoconductive layer contains binders and plasticizers, fluidity imparting agents, pinhole inhibitors, etc. similar to those used in the charge generation layer and charge transport layer of the composite photoconductive layer. Additives can be used. In this, the role of the binder is important. When a charge transport material is not used in a single-layer photoconductive layer, the binder has a ratio of 10 to the charge generating material.
It is preferable to use 0 to 900% by weight, especially 20% by weight.
It is preferable to use a weight of 0 to 400. The binder is 1
If it is less than 0.00% by weight, the charging property tends to be poor;
If it exceeds 0% by weight, sensitivity tends to decrease. In addition, when a charge generating material and a charge transporting material are used together, the binder is preferably used in an amount of 80 to 45 liters (more than 100 to 300 liters) more than the charge transporting material. If the amount is too small, the chargeability will be poor, and if it is too large, the sensitivity will be reduced.In this case, the charge generating material is preferably 0.1 to 20% of the total amount of the charge transporting material and the binder.
% by weight, particularly preferably from 0.5 to 5% by weight.

If the amount of the charge generating material is too small, the sensitivity will be reduced, and if it is too large, the charging property will be poor. others.

Additives such as plasticizers, flow agents, pinhole inhibitors, etc. are appropriately selected and used in the single-layer photoconductive layer in an amount of 5 weight percent or less.

The thickness of the single-layer photoconductive layer is preferably 5 to 50 μm, particularly preferably 8 to 20 μm. If the thickness is less than 5 μm, the charging property tends to be poor, and if it exceeds 50 μm, the sensitivity tends to decrease. To form a single-layer photoconductive layer, a charge generating material,
After uniformly dissolving or dispersing the charge transport material, binder and optional additives in the same solvent as for the charge generating layer described above.

It can be formed by coating and drying.

The photosensitive layer of the present invention is a multilayer photoconductive layer in which a charge transport layer similar to the charge transport layer in the composite photoconductive layer is formed immediately above or below the single layer photoconductive layer, or both. A conductive layer can be employed.

The electrophotographic photoreceptor according to the present invention may have a thin adhesive layer or barrier layer between the conductive layer and the photosensitive layer and immediately above the conductive layer.

Next, the protective layer formed on the surface of the photosensitive layer will be described in detail.

The protective layer can be obtained by curing a composition containing a specific butyl etherified melamine formaldehyde resin (AJ and a fluorine-containing resin (Bl) having a hydroxyl value of 5 to 100 and a fluorine atom in the polymer side chain by heating. .

Butyl etherified melamine used in the present invention
Formaldehyde resin (number average molecular weight of ~1.500
It is as follows. When the number average molecular weight exceeds 1.500, reactivity decreases. The resin also has 2 to 4 bound formaldehydes per melamine core. If the number exceeds 4, the reactivity decreases, and if the number is less than 2, the storage stability of the resin deteriorates and the cured film becomes brittle. Further, the resin has 1 to 2 methylol groups per melamine. If the number of methylol groups exceeds 2, the storage stability of the resin will be poor and the cured coating will become brittle. Moreover, if it is less than one, the reactivity is poor.

Such butyl etherified melamine/formaldehyde resin is produced by dissolving melamine in butanol and adding formaldehyde dropwise thereto to perform an addition reaction and butyl etherification.

Alternatively, it can be produced by dissolving melamine and formaldehyde in butanol and heating this solution to carry out an addition reaction and a butyl etherification reaction. In these methods, the reaction is performed using nitric acid or hydrochloric acid.

It is preferable to add an acidic catalyst such as sulfuric acid, phosphoric acid, p-)luenesulfonic acid, etc., and carry out the reaction at an acidic temperature, preferably pH 3 to 6. The reaction temperature is the reflux temperature of butanol, preferably about 9
Preferably, the temperature is 0 to 100°C. 'However, it is preferable to use 4 to 5 moles of butano/L/L and 3 to 7 moles of formaldehyde per mole of melamine.

The butyl etherified melamine/formaldehyde resin (A) used in the protective layer of the present invention can be cured at a lower temperature than conventional melamine resins, so it does not cause thermal deterioration of the electrophotographic photoreceptor during the formation of the Hoto layer. , a protective layer with high wear resistance can be formed.

Next, a fluorine-containing resin (Bl) having a hydroxyl value of 5 to 10o and a fluorine atom in the polymer side chain will be explained.

Conventionally, fluorine-containing resins are polyvinyl fluoride, polyvinylidene fluoride, and polyethylene trifluoride chloride.

Structures in which the fluorine atom f is directly bonded to the polymer main chain, as typified by polytetrafluoroethylene, tetrafluoroethylene and 67fluoropylene co-polymerization, Ihara combination of fluoroolefin and hydrocarbon vinyl ether monomer, etc. The resin of C was known. When trying to apply these fluorine-containing resins to the protective layer of an electrophotographic photoreceptor, ■ When using the coating method, they are poorly soluble in the alcohol-based and hydrocarbon-based solvents used to avoid damaging the lower photosensitive layer. Cannot be painted. (2) A protective layer made of a fluorine-containing resin alone has poor adhesion and low mechanical strength, so it is usually used in combination with another resin to form a single crosslinking stage, but it has poor compatibility with the resin used in combination. Therefore, a method is used in which the ratio of the fluorine-containing resin or the resin used in combination is increased, and one resin is used slightly. Since the crosslinking density is low, the mechanical strength is weak, and if only a small amount of the reverse pressure fluororesin is added, there is a problem that the wear resistance inherent to the fluororesin cannot be sufficiently improved. As described above, even when a conventional fluorine-containing resin having a structure in which a fluorine additive is directly bonded to a polymer main chain is used in the protective layer of an electrophotographic photoreceptor, no significant improvement in wear resistance can be expected.

J~Karuni A fluorine-containing resin having a hydroxyl value of 5 to 100 and fluorine in the polymer side chain, which is a component of the protective layer according to the present invention, is also soluble in alcohol, so it does not attack the underlying photosensitive layer. These resins can be coated easily, and each has high compatibility with the resin above, allowing them to be mixed in a wide range of ratios. In particular, the protection of the present invention! As a component of the layer, a film with unprecedented heat curing properties and high abrasion resistance can be obtained!
Specific butyl needered melamine formaldehyde resins (A and L) are compatible with each other, so they can be mixed in any ratio depending on the purpose.In this way, specific butyl etherified melamine formaldehyde resins [A] and a fluorine-containing resin with a hydroxyl value of 5 to 100 and a polymer side chain VC fluorine atom (by combining
The % length of both melamine resin and fluorine-containing resin can be expressed, slip properties can be added to hard hills, and a coated gold with zero toughness and high wear resistance can be obtained. In addition, the hydroxyl value is 5 to 10
A fluorine-containing resin having a fluorine atom in the polymer side chain with 0 is a fluorine-containing resin having a fluorine atom f directly bonded to the main chain.
Compared to resin, even a small amount used in combination is effective in improving wear resistance.

Here, fluorine-containing resin (81) having a hydroxyl value of 5 to 100 and having a fluorine atom in the polymer side chain (C can be obtained by the two methods described in F).

(1) Ordinary radical copolymer■ Monomer 1 which has a fluorine atom in its side chain and has no fluorine atom bonded to the carbon atom forming the carbon-carbon trilinear bond 1 For example, CH2=CHC00C Summer ■2CFs,
CHz=CI-ICOOCH2cHzcFzcFs,
CH2=C(C1ls)COOCHsCHzOCF
zCFzOCI-1zCF3-, CH2=C(CHs
)OCOCHzCHz (CF2)40F! , C
Hz=C(to CH2') C00CHzCFs, C
I-b=cHOcOcH* (CzHs) NC0C
2F! , CH2=CHOCOCH2CH2N (C
H3) 802 (CF217 CF3 and (2) Hydroxyl group-containing vinyl monomer 1 such as hydroxyethyl acrylate, hydroxyethyl methacrylate.

Hydroquinglovir acrylate, depending on the allyl alcohol base (1) Other copolymerizable vinyl monomers 1, such as methyl acrylate, methyl methacrylate, 1'l-globyl acrylate, isopropyl methacrylate.

2-ethylhexyl acrylate, vinyl acetate, vinyl caproate, sunalene, vinyltoluene, acrylamide, itaconic acid, fumaric acid, maleic acid, butadiene, vinyl chloride, vinylitine chloride.

Acrylonitrile, and even 9 with a fluorine atom in the main chain
For example, it can be obtained by copolymerizing fluoroolefin gold such as tetrafluoroethylene, dichlorodifluoroethylene, and talolotrifluoroethylenefluoropropylene. Copolymerization can be carried out by conventional methods such as bath liquid polymerization and non-water polymerization. Heavy temperature: 60-140'C
, the polymerization time is about 2 to 15 hours. toluene during polymerization.

Organic solvents such as quinolene, acetate, methyl ethyl ketone, and isopropanol can be used, and polymerization initiators such as benzoyl peroxide and azobisisobutyronitrile can be used in an amount of about 0.01 to 10% by weight based on the monomer. Can be used.

The ratio of monomers having fluorine atoms in their side chains in the copolymer is from 5 to 95% by weight! J: If the weight is less than 95% by weight, the effect of improving wear resistance, which is a feature of fluorine-containing resins, will be less apparent, and if it exceeds 95% by weight.

The compatibility with the specific butyl etherified melamine formaldehyde resin fA), which is a component of the protective layer of the present invention, decreases.

The ratio of the hydroxyl group-containing vinyl monomer (■) in the copolymer is:
The hydroxyl value of the copolymer is determined to be within the range of 5 to 100. If the hydroxyl value is less than 5, the crosslinking density with the specific butyl etherified melamine/formaldehyde resin (A) will be low, and there will be little effect on improving the abrasion resistance of the protective layer, and if the hydroxyl value exceeds 100i, the compatibility with (A) will be low. descend.

Further, the copolymerizable vinyl monomer of Ike (1) in the copolymer can be used in an appropriate amount in addition to the monomers (1) and (2) above. However, when using a monomer having a fluorine atom in the main chain as described above, if it is used in a large amount, the specific butyl etherified melamine/formaldehyde resin fA+ and Kashiwamochi properties will decrease, so it should not exceed 10% by weight in the copolymer. It is preferable to use

(2) Using a compound containing two or more peroxy bonds or azo bonds that generate all radicals that can initiate polymerization by thermal decomposition in the block copolymer molecule, some of the peroxy bonds or azo bonds are removed by heat. Using the radicals generated by decomposition (11), polymerize the monomer, then thermally decompose the remaining peroxy bonds or azo bonds without thermal decomposition, and use the radicals generated (1). By polymerizing the monomer (11), which is different from the monomer (11), a block copolymer of the monomer (11.m) and the monomer (11) can be obtained.

Compounds containing two or more peroxy bonds or azo bonds in the molecule include (a) dihydric alcohols such as ethylene glycol, furopylene gelicol, and diethylene glycol, and (b) succinic acid, adipic acid, cepatic acid, and cyclohexane. Dibasic acids such as dicarboxylic acids or their acid anhydrides; (c) oxyacids such as glycolic acid, α-oxyinobutyric acid, and hydroxyacrylic acid; (d) peroxyconocarboxylic acid, peroxyadipic acid, peroxyphthalic acid, etc. A peroxy bond is introduced into the molecule in the form of a polyester by using the bero-7 acid of C condensation reaction. Using this technique, it is also possible to obtain a compound containing an azo bond in the molecule in the form of a polyester by a condensation reaction. -For example, there is a compound ◇rv'5.1 Zenko ~ Tsuri λ') Ki Vt-t;
'h; 4゜Next, react with a compound having a peroxy bond or an azo bond in such a molecule (1) or (11
) The monomers ① to ② shown in (1) can be used. For example, when (11) monomer is used, the iIL polymer of the beam is used as the monomer (11), and the monomer (2) is used as the monomer (1). When used,
(The monomer (■) can be used as the Il+ monomer. In these cases, the monomer (1) can be contained in the monomer (1) and (11). can.

In any case, first, the monomer (1) is reacted with a compound having two or more peroxy bonds or azo bonds in the molecule, which can be decomposed by heating to generate radicals capable of initiating one reaction. ) After obtaining a bundle of the monomers of (11) and 0-order remaining peroxy bonds or azo bonds are reacted with the monomer of (11), a block of the polymer of (1) and the polymer of (11) is obtained. A copolymer can be obtained.

As a method for such block coelectrolysis, there is no ordinary melting method.
It can be done by methods such as pJ, m-polymerization, and non-aqueous dispersion polymerization.

The enrichment temperature and i gold time are both 60 to 140°C when obtaining the blood coalescence of (1) and when obtaining the polymer of (11).

This is carried out for 2 to 15 hours, in order to allow some of the beluoxy bonds or azo bonds to remain when obtaining one polymer of (1), compared to when obtaining a zero-order polymer of (11).

Low temperature and short time are preferred. toluene during polymerization.

Organic solvents such as xylene, acetone, methyl ethyl ketone, and isopropanol can be used.

The ratio of the monomers (1), (2) and (2) in the block copolymer is the same as in the case of the radical copolymer (1) described above,
The reason is also the same.

Next, a specific butyl etherified melamine/formaldehyde resin (Al and a 7-chain resin with a hydroxyl value of 5 to 100 and a fluorine atom in the polymer side chain (Bl) is used at a ratio of xii ratio fA)/(Bl is 9515~15/8
It is 5. If this weight ratio is too large, the effect of improving the abrasion resistance of the protective layer will be small, and if it is too small, the mechanical strength of the protective layer will be poor.

As described above, for the formation of the protective layer in the present invention (A
Although two types of substances, 1 and (Bl), are used, additives such as a fluidity imparting agent and a bottle hole suppressing agent used in the photosensitive layer described above may be further added as appropriate.

Also (hydrochloric acid, sulfuric acid, and phosphoric acid, which serve as curing catalysts for the components).

p-Toluenesulfonic acid, dodecylbenzenesulfonic acid, etc. are also problematic (0.00% per 100 parts of the total amount of Bl component).
01 to 10 parts by weight can be used.

When forming a protective layer, use the above-mentioned specific butyl etherified melamine/formaldehyde resin (AI and a fluorine-containing resin CB+ having a hydroxyl value of 5 to 100 and having a fluorine atom in the polymer side chain, and a curing catalyst and addition as necessary). After uniformly dissolving or dispersing the agent etc. in a solvent, apply it for 90 minutes.
It can be formed by heating and drying at ~140°C.

The thickness of the protective layer is 0.01 to 10 μm. 0.01μ
If it is less than m, the effect as a protective layer will be low and the durability will be poor.
If it exceeds to μm'fc, the sensitivity tends to be poor and the residual potential tends to increase.

The electrophotographic photoreceptor according to the present invention can be electrostatically charged for 1 M, s by charging its surface and applying g-light by a generally well-known method.
After forming an image, it is developed and used to transfer the image onto a transfer medium such as plain paper.

(Function) The protective layer of the present invention uses, as its raw materials, the butyl etherified melamine-formaldehyde resin (containing the above-mentioned butyl etherified melamine-formaldehyde resin) which itself can be thermally cured at a relatively low temperature and has excellent abrasion resistance, and the resin (A).
Good compatibility with l and wear resistance.

By using a fluorine-containing resin (Bl), which has a fluorine atom in the polymer side chain and has excellent slip properties, the protective film can be formed at low temperatures and in a short time.

When forming the protective layer, the electrophotographic photoreceptor's properties are not deteriorated by metal heat, and even a thin film can form a strong protective layer. Furthermore, the protective layer has good slip properties, and an electrophotographic photoreceptor with good electrophotographic properties and excellent durability can be obtained.

(Leprosy Example) Next, the present invention will be described in detail based on Examples, but the present invention is not limited thereto.

Each material used in the examples below is listed below. Abbreviations are shown in parentheses.

(1) Charge-generating organic pigment 7wm metal phthalocyanine (τ-H2PC) (2) Charge-transporting substance 2-(p-dimethylaminophenyl)-4-(p-dimethylamine)phenyl-5-(o-chloro phenyl)−
1,3-Oxazole (OXZI (3) 0 binder silicone varnish: KR, -255C [Cho Chemical Industry ■Product name] Solid content 50 coulometric factor 0 Polyester pine resin: Byron 200 [Toyobo (Kiku product name)] ( 4) Material for protective layer (AJ Butyl etherified melamine formaldehyde resin (BMF) (synthesis of BMF-1) In a flask equipped with a stirrer, reflux condenser, and thermometer, 125 g of melamine, 4449 n-butanol, and 61 g of n-butanol were added. Add 0.2 g of nitric acid aqueous solution and io.

After raising the temperature to ℃, 169 g of rose formaldehyde was divided into 6 portions and added at equal intervals in 6 portions for 30 minutes.Then, the reaction was carried out at reflux temperature for 30 minutes, water was removed, and the heating residue was 50 ℃. The solvent was removed so that the weight was 8%. The resulting resin solution had a viscosity of B according to Gardner (25°C).

(Synthesis of BMF'-2) Using the same apparatus as in the synthesis of BMF'-1, 217.5 g of rose formaldehyde and 4 g of n-butanol were placed in a flask.
Add 44g and 126g of melamine.

The addition reaction was carried out at 90-100°C for 30 minutes. then 4
Cool to 0-45°C and add 1g of phthalic acid.

Reflux dehydration and dissolution were performed under acidic conditions. After this.

The heating residue was adjusted to 50 cm. The viscosity at this time was B in Gardner (25°C).

Table 1 shows the number of formaldehyde bound, the number of butyl ether groups, the number of methylol groups, and the number average molecule t per melamine nucleus of BMF-1 and BMF-2.

However, the number of bound formaldehyde is determined by measuring the amount of unreacted formaldehyde using the charged amount and the sodium sulfite method, and the number of butyl ether groups is determined by measuring the amount of charged butanol and the amount of unreacted formaldehyde using gas chromatography using 5ec-butyl alcohol as an internal standard solution. The methylol group was determined from the above-mentioned number of butyl ether groups and the NtVl spectrum. Further, the number average molecular weight was determined by gel permeation chromatography using a standard polystyrene calibration curve.

Table 1 Characteristics of butyl etherified melamine/formaldehyde resin tB) Fluorine-containing resin with a hydroxyl value of 5 to 100 and containing a fluorine atom in the polymer side chain O fluorine-containing vinyl type monomer is CH2 = CHCOOCH
zCHzCnF2n+t (n = 8 to 14) and Futsumo Dayver F100C NOF ■Product name] 0 fluorine-containing vinyl type monomer is C) b = cHcOOCII2C1r2
A fluorine-containing resin containing CnF2 n++ ('' = 8 to 14) in a weight range of about 25% and having a hydroxyl value of 55; Modeiper F 200 (NOF ■Product name) Comparative Example 1 τ-HzPc '2. .Og, silicone face 4.
0 g and tetrahydrofuran 949'i ball mill (3-inch bot mill manufactured by Nihon Kagaku Togyo Co., Ltd.) for 8 hours. The obtained pigment dispersion was applied onto an aluminum plate (thickness: 0.1 mm) using an applicator.

It was dried at 90° C. for 1 hour to form a charge generation layer with a thickness of about 1.0 μm.

Next, oxz s g and polyester resin 159i were mixed with tetrahydrofuran 1409 and completely dissolved. The resulting solution was applied onto the charge generation layer using an applicator and dried at 90° C. for 20 minutes to form a charge transport I of 15 μm, thereby producing a composite electrophotographic photoreceptor.

Comparative Example 2 0XZ109 and polyester resin 109 were mixed with Tetrahydro7ran 809 and completely dissolved in the bath.

The obtained bath solution was semi-applied onto an aluminum plate using an applicator and dried at 90° C. for 1 hour to form a charge transport layer of 15 μIn.

Next, τ-11d'c 2. A pigment dispersion obtained by kneading for 15 hours using a mixed bath medium 949Q ball mill containing 4.0 g of Og, 7 silicone 1 nonis and toluene/inoglobanol = 476 (mass ratio) was placed on the charge transport layer of 1111. Coated with an applicator and heated to 110℃ for 15 minutes.
Dry for minutes to form a charge generation layer with a thickness of about 1.0 μm,
A composite electrophotographic photoreceptor was fabricated.

Comparative Example 3 τ-H2P cOob ge OX Z5. Og
-' 14.4 g of polyester resin and 80 g of tetrahydrofuran were kneaded for 10 hours using a ball mill. The resulting dispersion was applied onto an aluminum plate using an applicator and dried at 100° C. for 15 minutes to produce a single-layer electrophotographic photoreceptor having a film thickness of 15 μm.

Comparative Examples 4 to 5 A bath solution consisting of 40 g (solid content: 20 g) of BMF-2 and Improper Tool 609 was applied onto a photoreceptor (underlying photoreceptor) prepared in the same manner as in Comparative Example 1 using an applicator. Processing 9 A protective layer was formed by heating under the curing conditions shown in Table 2. Table 2 shows the thickness of the protective layer.

Comparative Example 6 A bath solution consisting of B~iF'-1,409 (20 g in solid content) and 60 g of Improper Tool was applied onto a photoreceptor (underlying photoreceptor) prepared in the same manner as in Comparative Example 1 using an applicator. It was coated and heated at 110° C. for 1 hour to form a protective layer. Table 2 shows the thickness of the protective layer.

Examples 1 to 6 Materials having the composition shown in Table 2 were placed on a photoreceptor (underlying photoreceptor) prepared in the same manner as in Comparative Examples 1 to 3 in a mixed bath of tetrahydrofuran/isobutanol = 171 (by weight: 1). A bath liquid having a solid content of 20'fEc and a tii' ratio of 1+.1 was spooled with an applicator and heated under the curing conditions shown in Table 2 to form a protected rf4.

Table 2 shows the thickness of each protective layer.

Table 3 below shows the electrophotographic characteristics of the electrophotographic photoreceptors obtained in Comparative Examples 1 to 6 and Examples 1 to 6, measured using a total electrostatic recording tester (■ Tsukihi Denki Seisakusho 5P-428). Shown below.

Note that the initial potential V in Table 3. (V) indicates the charged potential when 5 Kv corona gold was discharged for 10 seconds in dynamic measurement, and dark decay VK indicates the potential retention rate when left in a dark place for 30 seconds.HE5°.

E75 is irradiated with 10 ffux white light and the light amount value required for the potential to decrease by 50% and 75%, respectively [gx-s]
shows. The residual potential VR (V) indicates the surface potential after irradiation with 10 lux white light for 10 seconds.

In addition, using a friction tester (manufactured by Suga Test Instruments), the surface of the electrophotographic photoreceptor was rubbed with gauze to remove wear scratches on the surface.
The abrasion resistance was evaluated by the number of times it was slid through the layer until it reached the layer below. The results are shown in Table 3.

Continuous printing tests were also conducted using a 1Ifii image evaluation machine.

The total number of printed sheets was counted until the image quality deteriorated, and the printing life was evaluated. The results are also shown in Table 3 VC.

Although the photoreceptors of Comparative Examples 1 to 3 have good electrophotographic properties, since no protective layer is provided, the abrasion resistance is low and the printing life is less than 2,000 sheets. In addition, a melamine resin (B
When MF-2) is used alone, curing is insufficient at a low temperature (110° C.) for a short time (1 hour), and no improvement in wear resistance is observed (Comparative Example 4). High curing temperature (160°C)
west.

When the curing time is increased to 3 hours, the abrasion resistance improves a little, but the electrophotographic properties deteriorate due to thermal deterioration of the material, and in particular, the half-reduction and residual potential increase significantly.

Background stains occurred in the image (Comparative Example 5).

Next, the photoreceptor of Comparative Example 6 is a case where the butyl etherified melamine formaldehyde resin (BMF-1) of the present invention is used alone, but since it is cured at low temperature and in a short time, there is no thermal deterioration of the material during that time. This is negligible, and almost no deterioration in electrophotographic properties due to the provision of the protective layer is observed even when compared with Comparative Example 1. In addition, the wear resistance was greatly improved compared to Comparative Examples 1 to 5, but the printing life was only 1,50 years.
There were 0 pieces.

However, certain butyl etherified melamine compounds,
The photoreceptors of Examples 1 to 6 according to the present invention, in which a fluorine-containing resin having a hydroxyl value of 5 to 100 and having a fluorine atom in the polymer side chain, were used as the protective layer for the aldehyde resin. Since it hardens over time, ν), there is no deterioration in electrophotographic properties due to thermal deterioration during protection 1-formation, and it continues to have better electrophotographic properties compared to the photoreceptors of Comparative Examples 1 to 3. Furthermore, the wear resistance.

In addition to the hardness of the specific butyl etherified melamine/formaldehyde resin, the slipperiness of the fluorine-containing resin having fluorine atoms in the polymer side chain was added, resulting in a significant improvement. It is capable of doing so, and the printing life is also extended, both of which are 60 years old.
．． It had a printing life of more than 1,000 sheets.

(Effect of the invention) The surface of the present invention is coated with a specific butyl etherified melamine/formaldehyde resin (with an Al and hydroxyl value of 5 to 10).
An electrophotographic photoreceptor having a protective layer containing a fluorine-containing resin (131t-component) containing a fluorine-containing resin having a fluorine atom in the polymer side chain and having an IIψ coating of 0 and a fluorine atom in the polymer side chain.

This is an electrophotographic photoreceptor with excellent electrophotographic properties and long printing life.

Claims (1)

[Claims] 1. On the surface of the photosensitive layer, a butyl etherified melamine/formaldehyde resin (with a number average molecular weight of 1,500 or less, a number of bound formaldehydes per melamine nucleus of 2 to 4, and a number of methylol groups of 1 to 2) is applied. An electrophotographic photoreceptor comprising a protective layer containing a cured film containing as components A) and a fluorine-containing resin (B) having a hydroxyl value of 5 to 100 and having a fluorine atom in a polymer side chain.