JPS59231546A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled photosensitive body superior in electrostatic characteristics, sensitivity, and durability, and stable in repeated uses by forming on a substrate a photosensitive layer obtained by dispersing a specified photoconductor powder into a specified thermosetting acrylic resin binder. CONSTITUTION:An electrophotographic sensitive body is manufactured by forming on a substrate a photosensitive layer obtained by dispersing a phthalocyanine type photoconductor powder into a binder. This binder is a thermosetting acrylic resin having amide bonds obtained by radically polymerizing a monomer mixture of (A) 10-50wt% styrene monomer, (B) 10-40wt% monomer of formula I (R1 is H or methyl; R2 is 1-12C alkyl), and (C) 3-30wt% monomer of formula II (R1 is same as said R1, and R3 is H, methylol, or alkoxymethyl), a mixture of said mixture and 1-10wt% alpha-methylstyrene, acrylonitrile, (meth)acrylic acid, or the like. The electrophotographic sensitive body thus obtained is superior in electrostatic characteristics and sensitivity, and stable against repeated uses, and superior in durability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor comprising a photosensitive layer formed on a substrate, in which particles of a photoconductive material are dispersed in a laminate made of an insulating molecular material. This invention relates to improvements in electrophotographic photoreceptors.

In general, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged and exposed to form an electrostatic latent image, which is developed with a developer to make it visible, and the visible image is directly converted into a 1δ
A copy image is obtained by fixing it on a photoreceptor, or a so-called PPC method is used, in which a visible image on a photoreceptor is transferred onto a transfer paper such as paper and the transferred image is fixed to obtain a copy image. be.

Conventionally, amorphous selenium, cadmium sulfide, or zinc oxide has been widely used as a photo-quaternary material to form the photosensitive layer of electrophotographic photoreceptors used for this type of purpose, but amorphous selenium It requires vapor deposition on a conductive support, making it easy to manufacture, and the vapor-deposited film is not flammable, is highly toxic, requires careful handling, and is expensive.
On the other hand, with cadmium sulfide and zinc oxide, they are
Sensitivity is affected by the mixing ratio of the binder used to attach the CM, so in order to obtain a practical sensitivity, the proportion of the binder must be reduced.As a result, the combustibility and smoothness ,
It has low mechanical strength such as glare intensity and abrasion resistance, and its properties deteriorate due to ozone, etc. generated due to corona charging.In addition, it is toxic and may cause environmental pollution. I ran into problems.

In order to solve these shortcomings and problems, various research and developments have been carried out,
In recent years, for example, JP-A-50'-38543, JP-A-51-95852, and JP-A-53-64040.
A photoreceptor using a phthalocyanine thread-leading conductive material has been proposed in Japanese Patent Application Laid-open No. 53-83744 and the like. This type of photoreceptor has excellent processability and sensitivity,
It is known that there are no problems with radiation, and that it exhibits high sensitivity even to long wavelength light such as that of semiconductor lasers. It is also known that the properties of this type of photoreceptor, such as electrostatic properties, moisture resistance, and durability, vary greatly depending on the type of binder used in combination with the photoconductive material.

Therefore, as the M adhesive, the electrophotographic properties of the photoconductive substance,
For example, it is required not to impair charging characteristics, sensitivity, custom-made power reduction characteristics, repeatability characteristics, etc.

In general, the binder type photoreceptor 1c2, which is formed by dispersing a photoconductive material in an IM shielding agent and forming a photosensitive layer on a substrate, uses silicone resin, epoxy resin, etc. as the binder.
Alkyd resins, vinyl resins, acrylic resins, urethane resins, etc. are used, but when these resins are combined with gold phthalocyanine photoconductive materials to form a photoreceptor, electrons generated inside the photosensitive layer are transferred to the surface of the photosensitive layer. As a result, there are problems such as the disappearance of surface charge, that is, it takes time to form an electrostatic calendar (induction effect), and the problem that performance deteriorates significantly during repeated use. However, the problem has often been that it is difficult to fully utilize the properties of the phthalocyanine fiber photoprotective coating. By the way, when silicone resin is used as a binder, the charging property is low, and with epoxy resin, sufficient sensitivity cannot be obtained, while with urethane resin, the charging property, dark decay property, device strength, etc. are good, but the sensitivity is low. However, there is a problem in that printing durability due to electrophotographic properties is lacking in repeated use.

The purpose of this research is to improve the electrophotographic properties of a J-age photon for electrophotography using a phthalocyanine-based photoconductive material, in particular, to improve the sensitivity, gradation, and 11U printability, as well as to improve the stability during repeated use. , Moisture resistance, 11 "Improving durability."

As a result of conducting various 4'df studies in order to achieve the above object, the present invention has developed 'electrophotographic properties' by using a thermosetting acrylic resin, particularly a thermosetting acrylic resin containing an amide group, as a binder. Thermosetting acrylic resin and melamine resin that can be improved and also contain amide groups kg
By using it together as a shielding agent, the lIl! of the photosensitive layer can be improved. This was based on the discovery that it was possible to improve printing durability, printing durability, and stability during repeated use.

That is, the gist of the present invention is to provide an electrophotographic photoreceptor in which a photosensitive layer formed on a substrate is formed by dispersing a phthalocyanine thread photoconductive material powder in a binder, wherein mJ is the main component of the binder. is a monomer represented by 10 to 40% by weight of styrene (where kl is hydrogen or a methyl group, and R2 is an alkyl group having 1 to 12 carbon atoms), and the general formula: (wherein, R1 is hydrogen or a methyl group, R3 is hydrogen, a methylol group, or an alkoxymethyl imk. At least one monomer selected from the group consisting of α-methylstyrene, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, and itaconic acid. An electrophotographic photoreceptor characterized in that it is an amide bond-containing thermosetting acrylic resin obtained by radical polymerizing a mixture of 10% to 10%.

In a second embodiment of the present study, a mixture consisting of 40 to 95% by weight of the amide-bonded gold-forming acrylic resin and 5 to 60% by weight of melamine is used as the M adhesive. Further, the appropriate molecular weight of the amide-bonded gold-curable acrylic resin is 2,000 to 40,000.

As the phthalocyanine thread photoconductive material used in the present invention, any of the per se known phthalocyanines and their derivatives can be used, and specifically, aluminum phthalocyanine, vanadium phthalocyanine, tin phthalocyanine, antimony phthalocyanine, barium phthalocyanine, and beryllium phthalocyanine. Phthalocyanine, vanadium phthalocyanine, cobalt phthalocyanine, cobalt chlorophthalocyanine,! -4-aminocyanine, copper-4-chlorophthalocyanine, copper phthalocyanine, dysprosium phthalocyanine, germanium phthalocyanine, holmium phthalocyanine, phthalocyanine, iron phorihalophthalocyanine, lead phthalocyanine, lead phorichlorophthalocyanine, cobalt hexaphenyl phthalocyanine, platinum Metal-free phthalocyanine compounds such as 7-thalocyanine and zinc phthalocyanine; dialkylaminophthalocyanine, tetraazophthalocyanine, tetramethylphthalocyanine, and tetraphenylphthalocyanine are preferred, and these can be used alone or in combination.

A phthalocyanine-induced phthalocyanine in which the hydrogen atom of the benzene nucleus in the phthalocyanine molecule is substituted with at least one electron-withdrawing group selected from the group consisting of a nitro group, a cyano group, a halogen atom, a nurphone group, and a carboxyl group. Alternatively, at least -m and at least one unsubstituted phthalocyanine compound selected from phthalocyanine and the above-mentioned phthalocyanine compounds are mixed with an inorganic acid capable of forming a salt with them, and then mixed with water or a radial substance. It is also possible to use phthalocyanine thread photoconductive material compositions obtained by precipitation. in this case,
The electron-withdrawing group-substituted phthalocyanine derivative can be any one having 1 to 16 substituents in the molecule, and the composition of the electron-withdrawing group-substituted phthalocyanine derivative and other unsubstituted phthalocyanine compounds. The ratio is defined as the number of the former substituents per molecule of unit phthalocyanine in the composition.
．． The number is preferably 0.001 to 2, preferably 0.002 to 1. Examples of inorganic acids that can be formed into salts with the phthalocyanine compound used in producing the phthalocyanine photoconductive lamp composition described by RiJ include sulfuric acid, orthophosphoric acid, chloronurphonic acid, hydrochloric acid, hydriodic acid,
Examples include hydrofluoric acid and hydrobromic acid.

Among the photoconductive materials, those particularly suitable for the purpose of the present invention include metal-free phthalocyanines, copper phthalocyanines and derivatives thereof, such as nuclear halogen substituted layer conductors.

Regarding the blending ratio of the phthalocyanine-based photoconductive material described in 011 and the binder described in niJ, if the amount of the former increases, then 1
However, if the amount of the former decreases, the dark decay will decrease, but the sensitivity will decrease. Therefore, the amount of fireflies made of the original tetraelectric material is 1 for every 100 parts of the box-shield agent.
5 to 120M parts, preferably 25 to 100 parts by weight. is suitable.

General formula as a raw material for the amide bond-containing heat-transformable acrylic resin made from the main component of the binder: (In the formula, R1 is hydrogen or a methyl group, and R2 is a prime number of 1 to
12 (representing an alkyl group) include methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate, propyl acrylate, butyl methacrylate, butyl acrylate, and methacrylate. Contains acid lauryl, acrylic lauryl, etc.

In addition, monomers represented by the general formula: (wherein R1 represents hydrogen or a methyl group, and R3 represents hydrogen, a methylol group, or an alkoxymethyl group) include acrylamide, methacrylamide,
N-methylolacrylamide, N-n-butoxymethylacrylamide, and N-alkoxymethylacrylamide with a fineness prime number of 1 to 4 are included.

Styrene contributes to improving the chargeability of the photoreceptor, and its content is preferably 10 to 50% by weight. The monomer represented by general formula (1) is Il! I! It contributes to improving quality and printing durability, and its content is preferably 10 to 40%. In addition, the monomer having an amide bond represented by the general formula (2) contributes to improvement of various properties such as sensitivity, repeatability, charge retention ability, and printing durability, but its content is A preferable amount is ~30%, preferably 5~20%.

In addition, at least one monomer selected from the group consisting of α-methylstyrene, acrylonitrile, [+2 vinyl, acrylic acid, methacrylic acid, maleic acid, and itaconic acid is used as necessary, but its content is The amount is 1-1
0 weight plate % is suitable.

The amide bond-containing thermosetting acrylic resin is prepared by combining the monomers with butyl alcohol and aromatic acid 2000-40 in the appropriate proportions.
It is preferable to use all those having a molecular weight of 0.000 and a sharp distortion corresponding to the molecular weight. This is because if the average molecular weight exceeds 40,000, the hardness of the photosensitive layer will be low and no improvement in printing durability can be expected; 1. This is because the sharper the molecular weight distribution, the more constant the degree, and the higher the charge retention ability.Also, this amide bond-containing thermosetting acrylamide has a non-volatile content of 50%. When the viscosity is 2 at 25℃
00-3000 CPS is preferred. (This has a viscosity of 3000 Cps) Otherwise, the branching property of the photoconducting material will be poor, and conversely, if it is lower than 200, the sensitivity will decrease and the coating properties will deteriorate, causing defects and holes in the photosensitive layer. It is from. Furthermore, the acid value of the thermosetting acrylic resin is suitably 1 to 15.

Melamine resins that can be used as a component of the binder together with this amide bond-containing thermosetting acrylic 4# resin include butylated melamine resin, methylated melamine resin, butylated benzoguanamine resin, methylated benzoguanamine resin, etc. Among these, butylated melamine side fat is preferred.

When the amide-bonded gold-containing heat-transformable acrylic side fat and melamine resin are used together, the blending ratio thereof varies depending on the resin used, but is usually 95:5 to 40:60, preferably 90:10 to A weight ratio of 50:50 is preferred.

In the electrophotographic photoreceptor according to the present invention, the phthalocyanine-based photoconductive material powder is melted into a hydroxyl group-containing thermosetting acrylic resin, a melamine resin, and, if necessary, an epoxy resin, in a solvent. It can be obtained by uniformly dispersing the photoconductive coating material along with additives and sensitizers used depending on the conditions, applying the resulting photoconductive coating material onto a conductive substrate, and drying it.

In addition, in the electrophotographic photoreceptor of the present invention, the tetraelectric group is
Copper, aluminum, iron, silver, nickel, etc., formed into a foil, plate, or drum shape, or these metals deposited or electroplated on a plastic film are used. Ru.

The electrophotographic photoreceptor according to the present invention has a small induction effect peculiar to a photoreceptor using a phthalocyanine non-light-conducting tortoise preventive, has good gradation reproducibility and photosensitivity, and has continuous line 9
It has excellent stability of sensitivity upon reversal, high physical strength of the photosensitive layer, and good moisture resistance and printing durability. In addition, it not only improves rigid abrasion resistance and solvent resistance, but also improves stain resistance, and even if the surface of the photosensitive layer is abraded due to contact with developing brushes, transfer paper, cleaning rollers, etc. The quality of the Tawara photo image can be maintained well, and it can be used several times or more. Furthermore, those using an eyebrow agent containing epoxy resin show even better durability.

Examples of the present invention will be described below.

Example 1 Acrylamide XSO parts by weight, styrene 500 parts by weight,
350 parts by weight of ethyl methacrylate, 10 parts by weight of a free radical polymerization initiator (cumene hydroperoxide) and (-
Dodecyl mercaptan was dissolved in 1000 parts of n-butyl alcohol along with 10 Keishito in a reaction vessel, heated at reflux temperature with stirring, and 5 parts by weight of cumene hydroperoxide was added every 1.2 hours for a total of 6 hours. 1 C] Reaction was carried out to obtain a viscous and transparent solution having a nonvolatile content of 48 to 50% and a viscosity of 2500 Cps. 315 parts by weight of n-butyl alcohol-IV bath was prepared by dissolving 90 parts by weight of formaldehyde in this solution.
4 parts of anhydrous maleic alcohol were added to the mixture, and the amide groups and formaldehyde in the polymer were condensed by centrifugation for 31 minutes, and then 500 parts by weight of n-butyl alcohol and water were distilled off, and then 500 parts by weight of n-butyl alcohol and water were removed. Add a certain amount of toluene, pass through the mouth, non-volatile light content: 5096, viscosity: 700 CpS, molecular weight: 310
00 thermosetting acrylic resin was obtained.

The thermosetting acrylic resin solution weighs 80 parts (solid content 34 parts)
parts by weight), ε, type copper phthalocyanine (Toyo Ink Co., Ltd.)
] 20 parts by weight, 0.531 parts by weight of 2.4.7-)dinitro-9-fluorenone, 40 parts by weight of selonlupe acetate, 40 parts by weight of methyl ethyl ketone, and kneaded for 30 hours in a ball mill bot to obtain a photoconductive paint. Adjust the
This coating material was applied onto an aluminum substrate, dried, and cured by heating to produce an electrophotographic photoreceptor having an entire photoconductive layer having a thickness of 8 μm.

△! 7A Example 2 The thermosetting acrylic resin melted 68 weight S (
Using a composition consisting of 34 parts by weight of solids), 6 parts by weight of melamine resin (Super Beckamine J8201j product name, manufactured by Dainippon Ink Co., Ltd.), and 0.5 parts by weight of 2.4.7-dolinitro-9-fluorenone. An electrophotographic photoreceptor was produced in the same manner as in Example 1.

Example 3 Raw material monomers: 40 parts by weight of ethyl acrylate, 40 mfjt parts of styrene, 18 parts of N-methylolacrylamide
Using 2 parts by weight and 2 parts by weight of acrylic acid, the same procedure as in Example 1 was carried out to obtain a non-volatile content of 50% and a viscosity of 1200 CP.
A thermosetting acrylic #fj fat solution having a molecular weight of 2,800 was obtained. 40 parts by weight (solid content) of this thermosetting acrylic resin bath, 20 parts by weight of ε-type copper phthalocyanine, 2, 4, 7
．． 9-tetranitro-9-fluorenone 0.3 tL
Put Okibe, 40 parts by weight of 7-rosolve acetate, and 40 parts by weight of methyl ethyl ketone into a ball mill bottle, knead for 30 hours to form a photosensitive coating, transfer this coating onto an aluminum substrate, dry it, and then heat it. The electrophotographic photoreceptor was cured and had a photoconductive layer 8 microns thick.

△ Comparative Example 1 In Example 1, a melamine resin, Super Beckamine J820 (m product name, manufactured by Dainippon Ink Co., Ltd.), 40 parts by weight f: was used as a binder, but 8μ
An entire electrophotographic photoreceptor having a thick photoconductive layer was prepared.

Comparative Example 2 Heat II obtained in Example 1! ! Chemical acrylic fat (solid content 3
6 parts by weight) and epoxy &IIIL x vinyl I-) 10
An electrophotographic photoreceptor having a photoconductive layer with a thickness of 8 μm was obtained in exactly the same manner as in Example 1, except that 01, (trade name, manufactured by Shell Chemical Co., Ltd.) 4 Keirokube was used as the M layer agent.

Comparative Example 3 Same as Example 1 and 2, thermoplastic acrylic resin, oxt-'g7 (part name, manufactured by Mitsui Toatsu Chemical Co., Ltd.) 4 was used as the binding agent.
An electrophotographic photoreceptor having a photoconductor M having a thickness of 8 μm was produced in exactly the same manner except that a 0M hole was used.

Example 4 60 parts by weight of copper phthalocyanine and 0.5 parts by weight of dinitrocopper phthalocyanine were dissolved in 500 parts by weight of 98% concentrated sulfuric acid with thorough stirring, and this solution was poured into 3000 parts by weight of water to dissolve copper phthalocyanine. After precipitating the composition of dinitrocopper phthalocyanine, it is filtered, washed with water, and dried at 120° C. under reduced pressure.

15 parts by weight of the obtained phthalocyanine-based photoconductive composition and the thermosetting acrylic resin solution obtained in Example 3 (solid content: 4 parts by weight)
0 heavy parts), selonrugacetate) 40 M'R parts,
40 parts by weight of methyl ethyl ketone was placed in a ball mill bottle and kneaded for 40 hours to prepare a photoconductive paint. This paint was coated on an aluminum substrate, dried, and cured by heating to produce an electrophotographic image having a leading conductive layer of 8μ thickness. A photoreceptor for use was prepared.

Example 5 Thermosetting acrylic FI resin liquid obtained in Example 3 (commercial content: 32 coulometric parts), melamine resin (Suit Mabecamine J)
820) Using 8-fold part as a binder, this and ゛Example 4
Using 15 parts by weight of the phthalocyanine thread photoconductive composition obtained in Example 4, an electrophotographic photoreceptor having a photoconductive layer having a thickness of 8 μm was prepared in exactly the same manner as in Example 4.

Comparative Example 4 An electrophotographic photosensitive material having a thickness of 8 μm was prepared in the same manner as in Example 4, except that 40 parts by weight of Kumegukishi resin (Epicor 1001) was used as the binder. The body was created.

Comparative Example 5 Using 72 parts by weight of styrene, 20 parts by weight of ethyl acrylate, and 8 parts by weight of acrylic acid as raw materials, Example 1
In the same manner as above, the non-volatile content is 50% and the viscosity is 100%.
A thermosetting acrylic resin solution having a molecular weight of 0 CPS and a molecular weight of 25,000 was obtained. An electrophotographic photoreceptor having a photoconductive layer with a thickness of 8 μm was prepared in exactly the same manner as in Example 4, except that the obtained thermosetting acrylic resin solution (solid content: 40 parts by weight) was used as the M layer agent. O Ratio 11 Counterexample 6 Using 35 parts by weight of methyl ref, 40 parts by weight of methyl acrylate, 5 parts by weight of acrylic acid, 5 parts by weight of glycidyl methacrylate, and 15 parts by weight of butyl acrylate as raw materials, the same procedure as in Example 1 was carried out. , nonvolatile light content 50%, viscosity 110
One thermosetting acrylic resin bath having a molecular weight of 28,000 and a molecular weight of 28,000 was obtained. An IEW light for electrophotography having a photoconductive layer with a thickness of 8 μm was prepared in exactly the same manner as in Example 4, except that the obtained hot-setting acrylic resin solution (40 parts euhedral content) was used as a binder. The body was created.

All 11 types of photoreceptors manufactured as described above are commercially available powder image transfer j4! Each of the photoreceptors built in as a photoreceptor for an electrophotography machine was charged by +6.5 KV corona discharge, and the initial surface potential of each photoreceptor (Vo negative) and the initial surface potential (V
The exposure amount (E 1/2 (L
After charging, the surface potential (v5 (vl)) was measured at 1 m for 5 seconds.

1, V when performing Tawarasha Prosenu 1000 times.

The change in (△■o) and when a certain amount of exposure is given
3rd side 'tJt position (Vi (V)) Oxification (△Vi
(V) ) krtilJ was redundant. The results are shown in Table 1. In the table, for ΔvO9ΔVi, (l-) indicates an increase in surface potential, and (-) l-1 indicates a decrease in surface potential.

As is clear from the results in Table 1, the electrophotographic photoreceptor according to the present invention has a higher electrostatic charge than a comparative example, even when the same phthalocyanine fibers and fibers are used. Characteristic 2
It has excellent sensitivity and stability, is stable even after repeated use, and has excellent durability. Further, the photoreceptor of the present invention showed no change in the initial image quality and the image quality after 1000 sheets, and was able to obtain high image quality.

Patent applicant: Representative of Minolta Camera Co., Ltd. Patent attorney: Aoshi Aoba and 2 others

Claims (4)

[Claims] (1) An electrophotographic photoreceptor ICJ comprising a photosensitive layer formed by dispersing phthalocyanine non-photoconductive material powder in a laminating agent on a substrate, wherein the main component of the laminating agent is styrene. 10 to 50% by weight, 10 to 40% by weight of a monomer represented by the general formula = (in the formula, R1 represents hydrogen or a methyl group, and R2 represents an alkyl group having a binding number of 1 to 12); A monomer mixture consisting of 3 to 30% of the monomer represented by the formula: (wherein kl represents hydrogen or a methyl group, and R3 represents hydrogen, a methylol group, or an alkoxymethyl group), or A mixture of the mixture and 1 to 10% by weight of at least one monomer selected from the group consisting of α-methylstyrene, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, and itaconic acid is radically combined. An electrophotographic photoreceptor characterized by being an amide-bonded gold silently curing acrylic resin obtained. (2) OjJ thermosetting acrylic resin molecule 1 element is 2
The photoreceptor according to claim 1, which has a molecular weight of 000 to 40,000. (3) The photoreceptor according to claim 1, wherein the M layer agent comprises 40 to 95% by weight of an amide bond-containing thermosetting acrylic resin and 5 to 60% by weight of melamine resin. (4) Phthalocyanine thread The electrophotographic photoreceptor according to claim 1, wherein the photoconductive material is copper phthalocyanine, non-metallic phthalocyanine, or a mixture thereof.