JPH03191360A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a monolayer type photosensitive body sufficiently sensitive, especially, in the visible region of 400 - 700 nm freed of deterioration in electric chargeability due to repeated uses, superior in durability, and high in productivity by incorporating a specified azo pigment and a polyalkyleneglycol derivative in a photosensitive layer. CONSTITUTION:The photosensitive layer contains the azo pigment represented by formulae I and the polyalkylene glycol represented by formula II, and in these formulae I and II, A is a coupler residue; each of R1 and R2 is H, alkyl, or acyl; (n) is an integer of 2, 3, or 4; and (m) is an integer of 1-100. This photo sensitive layer is formed by dissolving or dispersing the charge generating material of the azo pigment of formula I, the charge transfer material of the polyalkylene glycol of formula II, and a binder resin in a proper solvent, coating a conductive substrate with the obtained solution or dispersion, and drying it, thus permitting the obtained electrophotographic sensitive body to be suffi ciently sensitive, especially, in the visible region of 400 - 700 nm, freed of deterio ration in chargeability due to repeated uses, superior in durability, and high in productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in an electrophotographic photoreceptor having a layer in which a charge generating substance is dispersed.

[Conventional technology]

2. Description of the Related Art Electrophotographic photoreceptors have been known that are provided with a charge generation layer containing a charge generation substance and various resins.

Examples of this include polyvinyl butyral (Japanese Patent Application Laid-open No. 58-105154), fatty acid cellulose ester (
JP-A No. 58-166353), acrylic resin with Tg of 70°C or less and an acid value of 10 to 40 (JP-A No. 58-1920)
No. 40), a mixture of a resin with a Tg of 70°C or less and a resin with a Tg of 75°C or more (JP-A-58-193549), a resin with lower compatibility in the charge-generating substance-resin-solvent system. -Re-dispersed by adding a solvent system (JP-A-56=1
No. 2646), polyvinylpyrrolidone (JP-A-56-1
No. 13140), polyvinyl formal resin (Japanese Patent Application Laid-Open No. 6
1235844) using a resin.

However, conventionally known photoreceptors have a problem in that the sensitivity and 1E conductivity against pre-exposure fatigue vary depending on the mixing ratio of the charge generating substance and the binder resin.

In other words, in conventional photoreceptors, sensitivity can be increased by reducing the amount of binder resin used for the charge-generating substance, but the chargeability deteriorates significantly due to pre-exposure fatigue, and conversely, the use of binder resin for the charge-generating substance If the amount is increased, it is possible to suppress a decrease in chargeability due to pre-exposure fatigue, but this includes the problem of a significant decrease in sensitivity.

Furthermore, in recent years, organic photoreceptors, particularly negatively charged photoreceptors in which a charge generation layer and a charge transfer layer are successively laminated on a support, have been widely used. This photoreceptor generates more ozone than the positively charged type, and therefore the surface of the photoreceptor is susceptible to chemical changes, resulting in blurred images and increased residual potential.

In addition, light yellow to light yellow compounds such as hydrazone compounds, pyrazoline compounds, oxazole compounds, and styryl compounds are used in the charge transfer layer.
Since a yellow hole transfer material is used, short wavelength light, such as blue light of 500 nm or less, is absorbed by this charge transfer layer, and such a photoreceptor has the disadvantage of extremely weak sensitivity in the short wavelength range. . This decrease in sensitivity is significant for blue light, and therefore the light attenuation effect cannot be achieved unless the light intensity is increased.However, increasing the light intensity in this way accumulates fatigue on the photoreceptor and reduces its durability. occurs.

On the other hand, in a positively charged photoreceptor in which a charge transfer layer and a charge generation layer are laminated in that order, the charge generation layer becomes the surface layer, and the surface layer wears out due to repeated processes of charging, exposure, development, transfer, and cleaning. and its durability decreases.

As a method to eliminate these drawbacks, a photoreceptor with a thicker charge generation layer has been proposed (Japanese Unexamined Patent Publication No. 59-2
24846, Japanese Patent Application Laid-Open No. 59-174849), this material has a short spectral wavelength range, so it has the disadvantage that it is not sensitive to yellow to red originals and cannot be used as a color photoreceptor.

Also, a single-layer type photoreceptor made of polyvinylcarbazole and trinitrofluorene is known, but this photoreceptor has the drawback of not having very high sensitivity.

[Problem to be solved by the invention]

It is an object of the present invention to provide a single-layer photoreceptor that has sufficient sensitivity particularly in the visible region of 400 to 700 nm, exhibits excellent durability without deterioration of chargeability even after repeated use, and has high productivity. do.

[Means to solve the problem]

According to the present invention, in a single-layer photoreceptor in which a photosensitive layer comprising a charge-generating substance, a charge-transfer substance, and a binder resin is provided on a conductive support, the photosensitive layer has an azozozoic acid represented by the following general formula (1). An electrophotographic photoreceptor characterized by containing a pigment and a polyalkylene gellicol compound represented by the following general formula (II) (wherein A represents a coupler residue) R1-○(CnHznO+-R2) (n) (wherein R1 and R2 are hydrogen, an alkyl group or an acyl group, and n is 2 to 4
m represents an integer from 1 to 100) Next, each constituent material used in the present invention will be explained.

The conductive support is intended to supply charges of opposite polarity to the charged charges to the substrate side, and has an electrical resistance of 1.
0"00m or less and can withstand the film formation conditions of the undercoat layer for the charge generation layer and charge transfer material. Examples of these include AQ, Ni, Cr,
Vacuum deposition, sputtering, and spray painting on the surfaces of electrically conductive metals and alloys such as Zn and stainless steel, inorganic insulating materials such as glass and ceramics, and organic insulating materials such as polyester, polyimide, phenol resin, nylon resin, and paper. AQ, Ni,
Cr, Zn, stainless steel, carbon, SnO□, In,
Examples include those coated with an electrically conductive substance such as O, etc. and subjected to conductive treatment.

The photosensitive layer includes a charge generating substance represented by the general formula (1),
A charge transfer substance, a resin binder, and the general formula (II
It can be formed by dissolving or dispersing the polyalkylene glycol compound represented by ) in a suitable solvent, coating the solution on a conductive support, and drying it. Moreover, a plasticizer, a leveling agent, etc. can also be added if necessary.

In the photosensitive layer of the present invention, as a charge generating substance, the general formula (
The azo pigment shown in 1) is used.

(In the formula, A represents a coupler residue) Examples of coupler residues include the following.

, where X, Ar”, Ar”, Ar”, R1,
R2 and R3 are as follows.

X: an aromatic ring such as a benzene ring or a naphthalene ring, or a hetero ring such as an indole ring, a carbazole ring, or a benzofuran ring, or a substituted product thereof, Ar'', Ar3: an aromatic ring such as a benzene ring or a naphthalene ring, or a hetero ring such as a dibenzofuran ring or a substituted product thereof; ^r2: an aromatic ring such as a benzene ring or a naphthalene ring or a substituted product thereof; RL, R3: hydrogen, a lower alkyl group or a diphenyl group, or a substituted product thereof.

R2: lower alkyl group, phenyl group, carboxyl group or ester thereof X, Ar1. Examples of the substituent in the substituent of Ar'' and Ar3 include an alkyl group, an alkoxy group, a halogen atom, and a nitro group.

Specific examples of azo pigments are shown below.

Face'' L Chest 11-To-11 Face 4 [Decoy 11-11-O Face 4L Glance 11-To-11 Face JL & - Face 4L Retired 111Δ--- As a charge transfer substance is poly-h-vinylcarazole and its derivatives, poly-γ-carbazolylethylglutamate and its derivatives, pyrene, formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivative, oxadiazole derivative, imidazole derivative , triphenylamine derivatives, 9-(p-diethylaminostyryl)anthracene, 1,1-bis-(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, etc. Examples include electron-donating substances.

As the resin binder, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer,
Polyvinyl acetate, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyltoluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine Examples include thermoplastic or thermosetting resins such as resins, urethane resins, phenol resins, and alkyd resins.

The ratio of the resin binder to the charge generating substance represented by the general formula (1) is preferably 10 to 50 parts by weight based on 100 weight parts of the resin binder.

If the amount of the charge generating substance used is less than 10 parts by weight, the sensitivity will be slow, and the position where the charge carriers are generated will be in the entire layer, making it difficult for the charge carriers generated near the substrate to move and being trapped, resulting in residual potential and brightness. The partial potential rises and stains occur on the background. Further, if the amount of the charge generating substance used exceeds 50 parts by weight, the charge level will decrease, resulting in a decrease in image density.

Further, it is preferable that the charge transfer substance is contained in an amount of 40 to 150 parts by weight based on 100 parts by weight of the resin binder. If the weight is less than 40%, sensitivity decreases and the residual potential increases. If the weight exceeds 150%, the mechanical strength of the photosensitive layer decreases, and abnormal images due to scratches and abrasion occur.

Further, in the present invention, the photosensitive layer may further include the general formula (I
A polyalkylene glycol compound represented by I) is contained.

These compounds have the effect of preventing charging deterioration due to injection from the conductive support or charging deterioration due to optical memory when the photoreceptor is used repeatedly, and the amount used is 2 parts by weight per 100 parts by weight of the resin binder. The amount used is preferably 10 to 10 parts by weight. If the amount used is less than 2 parts by weight, the effect of preventing charging deterioration will be reduced, and if it exceeds 10 parts by weight, an increase in bright area potential will occur, which is not preferable.

Representative examples of the compound represented by the general formula (n) are shown below.

[Representative examples of compounds represented by general formula (II)] polyethylene glycol, polypropylene glycol, polybutylene gelicol, glycerin monostearate, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene cetyl ether,
Polyethylene glycol monooleyl ester, polyethylene glycol distearyl ester, polyethylene glycol monostearyl ester, polyethylene glycol dioleyl ester, sorbitan monolaurate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, Polyoxyethylene lauryl ether, polyphenylene oxide, etc.

In addition, methods for applying the photosensitive liquid include dip coating method, spray coating method, spinner coating method, bead coating method, wire bar coating method, blade coating method, roller coating method,
Examples include coating methods such as a curtain coating method, and conventionally known methods such as a screen printing method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying can be carried out at a temperature of 30 to 200° C. for a period of from 5 minutes to 2 hours, either stationary or under ventilation.

Further, in the present invention, a protective layer can be provided on the intermediate layer in order to improve wear resistance, damage resistance, etc.

Protective layer resins include HeBS resin, AC3 resin, olefin vinyl copolymer resin, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide,
Polyamideimide, polyarylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene,
Examples include polyethylene terephthalate, polyimide, methacrylic resin, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene resin, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin.

In addition, from the viewpoint of wear resistance, polytetrafluoroethylene resin, fluorine resin, and silicone resin can be added as additives to lower the friction coefficient and improve wear resistance and scratch resistance. Abrasion resistance can also be improved by dispersing inorganic compounds such as tin oxide and potassium titanate in the resin. The thickness of this surface protective layer is 0.5 to 10 μm,
Preferably it is 1 to 5 μm.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention has sufficient sensitivity in the visible region of 400 to 700 nm, and exhibits excellent durability without deterioration in chargeability even after repeated use.

Moreover, it is highly productive.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that 1 part and % are both based on weight.

Example 1 An electrophotographic photoreceptor of the present invention was prepared by applying the following photosensitive layer coating solution onto an 80mm/340mm aluminum cylinder by spraying so that the dry film thickness was 22/jI11. The spectral sensitivity curve of such an electrophotographic photoreceptor is shown in FIG.

[Photosensitive layer coating liquid]

Polycarbonate resin (PCX-4 manufactured by Teijin) 2 parts Toluene 18 parts Comparative Example 1 A comparative electronic resin was prepared in the same manner as in Example 1 except that polyethylene glycol monostearyl was removed from the photosensitive layer coating solution. A photographic photoreceptor was created.

Example 2 Electrophotography of the present invention was produced in the same manner as in Example 1, except that the pigment Nα6 in the photosensitive layer coating solution was replaced with the pigment Nα1, and the polyethylene glycol monostearyl was replaced with polyethylene glycol monododecyl ether. A photoreceptor for this purpose was prepared.

Comparative Example 2 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that polyethylene glycol monododecyl ether was removed from the photosensitive layer coating solution.

Example 3 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 3 except that the charge transfer substance in Example 3 was replaced with polypropylene glycol monobutyl ether from the photosensitive layer coating solution. .

Example 4 In Example 3, the charge transfer substance was 13%, the polycarbonate resin was 13% polycarbonate resin (C-1
An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 1, except that polyethylene glycol monododecyl was replaced with polypropylene glycol monobutyl ether (Nuball LB-1800X, Sanyo Kasei Co., Ltd.). .

In Comparative Example 3, polycarbonate resin was mixed with polycarbonate 2 (Z-
An electrophotographic photoreceptor of the present invention was prepared in the same manner as in Example 3, except that polypropylene glycol monobutyl ether was replaced with polybutylene glycol (Teratane 2900, DuPont).

Comparative Example 4 A comparative electrophotographic photoreceptor was prepared in the same manner as in Example 4 except that polybutylene gellicol was removed from the photosensitive layer coating solution.

Next, the various photoreceptors obtained above were used in JP-A-60-1001.
It was attached to the apparatus shown in No. 67, rotated at 11,000 rpm, and discharged a voltage of +6 KV for 20 seconds in the dark.
After dark decay for seconds (Vo), 26Q of tungsten light
The sensitivity was determined by setting the amount of light at which the potential decreased by 1710 of VD as E1/10 by irradiating it for 20 seconds with ux, Surin 1 and width 6III+, and recording the progress of potential decay.

Further, these photoreceptors were mounted on FT-6550 manufactured by Ricoh Co., Ltd., and a durability test was conducted. The results are shown in Table-1.

Note that VD and vL each have a dark potential of 1.312ux-
It means the potential after irradiating the selling point of sec.

[Brief explanation of drawings]

FIG. 1 is a spectral sensitivity curve of the electrophotographic photoreceptor obtained by the present invention.

Claims (1)

[Claims] (1) In a single-layer photoreceptor in which a photosensitive layer consisting of a charge-generating substance, a charge-transfer substance, and a binder resin is provided on a conductive support, the photosensitive layer contains an azo pigment represented by the following general formula (I) and the following: Electrophotographic photoreceptor characterized by containing a polyalkylene glycol compound represented by the general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, A represents a coupler residue) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R_1 and R_2 represent hydrogen, an alkyl group, or an acyl group, n represents an integer from 2 to 4, and m represents an integer from 1 to 100.)