JPH01277249A - Photosensitive body - Google Patents

Abstract

PURPOSE:To improve the quality of an image by incorporating a copolymer of ethylenic hydrocarbon and acrylic ester and/or methacrylic ester as copolymerizable components and a photoconductive substance which does not practically exhibit sensitivity to light for imagewise exposure into an intermediate layer. CONSTITUTION:A copolymer of optionally substd. ethylenic hydrocarbon and acrylic ester and/or methacrylic ester as copolymerizable components is used as a binder in an intermediate layer 7 interposed between a photosensitive layer 8 and an electrically conductive support 1. The intermediate layer 7 contains a photoconductive substance which rectifies optical carriers generated in in the photosensitive layer 8 at the time of exposure without reducing resistance as bulk, increases sensitivity and can lower residual potential. Since the photoconductive substance does not practically exhibit sensitivity to light for imagewise exposure, the resistance of the intermediate layer 7 is kept moderate, the injection of holes from the support side is effectively prevented and the occurrence of black spots can further be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a photoreceptor, particularly an electrophotographic photoreceptor.

In the electrophotographic copying method of the prior art Carlson method, after the surface of a photoreceptor is charged, an electrostatic latent image is formed by exposure, the electrostatic latent image is developed with toner, and then the visible image is formed. Transfer and fix onto paper, etc. At the same time, the photoreceptor is subjected to removal of adhered toner, neutralization of static electricity, and surface cleaning, and is used repeatedly over a long period of time.

Therefore, as an electrophotographic photoreceptor, it is important to not only have electrophotographic properties such as good charging characteristics, good sensitivity, and low dark decay, but also physical properties such as printing durability, abrasion resistance, and moisture resistance after repeated use. It is also required to have good physical properties and resistance to ozone generated during corona discharge, ultraviolet rays during exposure, etc. (environmental resistance).

Conventionally, as electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide have been widely used.

On the other hand, the use of various organic photoconductive substances as materials for photosensitive layers of electrophotographic photoreceptors has been actively developed and researched in recent years. However, sensitivity and durability are not necessarily satisfactory.

For this reason, attempts have been made to develop organic photoreceptors with high sensitivity and durability by assigning the carrier generation function and carrier transport function to different substances in the photosensitive layer.

In such so-called function-separated type electrophotographic photoreceptors, substances that exhibit each function can be selected from a wide range of materials, so it is relatively easy to produce electrophotographic photoreceptors with arbitrary characteristics. Is possible. Therefore, it is expected that organic photoreceptors with high sensitivity and durability can be obtained.

FIG. 6 shows a functionally separated electrophotographic photoreceptor using such an organic photoconductive substance.

This electrophotographic photoreceptor has a structure in which a carrier generation layer 6 and a carrier transport layer 4 are sequentially laminated on a conductive substrate 1, and is used for negative charging. That is, the photosensitive layer 8 is composed of the carrier generation layer 6 and the carrier transport layer 4. In an electrophotographic photoreceptor having such a layer structure, since the mobility of holes is higher than that of electrons when negatively charged, it is possible to use photoconductive materials with hole transport properties that have good properties, and the photosensitivity is increased. It is advantageous in the following points.

However, these photoreceptors still have problems such as large fluctuations in repeat characteristics and environmental dependence during electrophotographic processes, and poor charging characteristics.
Reproducibility of electrophotographic properties is insufficient.

Furthermore, image defects such as white spots, black spots, roughness, and pinholes have not been sufficiently improved.

For example, as shown in FIG. 6, during negative charging, carrier injection from the conductive substrate or lower layer side tends to occur, which causes the surface charge to disappear or decrease microscopically.

This is particularly an image defect called a black spot in the reversal development method, and it significantly reduces the quality of the image.

Moreover, in the above-mentioned photoreceptor, the photosensitive layer is insufficiently attached to the conductive substrate, which also causes unfavorable characteristics.

As described above, no photoreceptor has been known that eliminates image defects such as black spots and has good photoreceptor characteristics.
A technical solution to these mutually contradictory issues has been desired.

Furthermore, in recent years, semiconductor laser light sources have been used in electrophotographic copying methods, which are inexpensive, compact, and capable of direct modulation. Currently, gallium-aluminum-arsenic (Ga-aluminum-arsenic) is widely used in semiconductor lasers.
The A l -As) based light emitting device has an oscillation wavelength of 750n.
It is about m or more. Many studies have been made in the past in order to obtain electrophotographic photoreceptors that are highly sensitive to such long wavelength light. Technological systems using such laser beams and the like are expected to be applied to printers, which is why it is desired that a useful image forming method using reversal development will emerge.

Object of the invention The object of the invention is to provide electrophotographic characteristics (repetitive potential characteristics,
A photoreceptor with good film quality (environmental dependence fluctuations, charging characteristics, sensitivity, residual potential), few image defects (white spots, black spots, roughness, pinholes, etc.), no moiré, and a good coating. It is about providing.

21 Structure of the invention and its effects, that is, the present invention provides a photoreceptor in which a photosensitive layer and an intermediate layer are provided on a conductive support, in which a substituted or unsubstituted ethylene hydrocarbon, an acrylic ester, and/or Alternatively, a photoreceptor characterized in that the intermediate layer contains a copolymer containing a methacrylic acid ester as a copolymerization component and a photoconductive substance that is substantially insensitive to imagewise exposure light. This is related.

According to the present invention, the material of the intermediate layer (particularly the intermediate layer between the photosensitive layer and the conductive support) provided on the photoreceptor, especially the binder composition, is the above-mentioned substituted or unsubstituted ethylene hydrocarbon and acrylic. It is extremely important to use a copolymer containing an acid ester and/or a methacrylic ester as a copolymerization component. That is, this copolymer (hereinafter referred to as the copolymer of the present invention) has a blocking function that effectively prevents the injection of holes from the support as described above, and prevents the injection of holes from the support side. It is considered that a barrier against local carrier injection can be provided, and it is possible to prevent surface charge from disappearing or decreasing due to local carrier injection. Therefore, especially when reversal development is performed, there are no black spots on the image, no white spots, roughness, or pinholes, and there is a remarkable effect of obtaining a high-quality image without image defects. be able to.

This intermediate layer contains a photoconductive substance, which exhibits rectifying properties for photocarriers generated in the photosensitive layer during exposure without reducing bulk resistance, improving sensitivity and reducing residual potential. can be reduced. Moreover, since this photoconductive material is virtually insensitive to imagewise exposure light, the resistance of the intermediate layer is maintained at an appropriate level, making it possible to effectively inject holes from the support side. It is possible to further prevent the above-mentioned black spots and the like. In order to obtain these effects, the photoconductive substance has a sensitivity of 171% during image exposure compared to the photoconductive substance in the photosensitive layer.
It is desirable that the sensitivity is 0 or less; that is, if the sensitivity of the photoconductive substance in the intermediate layer exceeds the sensitivity of the photoconductive substance in the photosensitive layer at 1710 during imagewise exposure, the resistance of the intermediate layer decreases during imagewise exposure. This is because holes are more likely to be injected from the support, and the holes are likely to move to the surface of the non-exposed area, resulting in black spots and the like. However, in order to provide rectification for photocarriers in the intermediate layer, the photoconductive material must have a certain level of photoconductivity, and the sensitivity of the photoconductive material in the photosensitive layer is 115 or less. It is further desirable to exhibit a sensitivity of 1710 or less.

Note that since the thickness of the intermediate layer can be made relatively large, the above-mentioned blocking function can also be improved at the same time.

In addition, in this intermediate layer, if the copolymer component consists only of substituted or unsubstituted ethylene hydrocarbon (in this case, it becomes a homopolymer), the adhesion to the substrate will not be sufficient. , acrylic acid ester and/or methacrylic acid ester are copolymerized as copolymerization components, so that the adhesion to the base (film attachment) is good. Therefore, this intermediate layer can fully exhibit the above-mentioned functions. This will be further promoted by selecting a combination in which the intermediate layer can be formed thicker than the so-called undercoat layer, and is difficult to dissolve during coating and formation of the upper layer. In addition, since it is relatively thick, incident light is easily scattered in the intermediate layer, and the occurrence of moiré (interference fringes on an image) can be eliminated.

Since the photoreceptor of the present invention has the above-mentioned excellent intermediate layer, an image is formed using a semiconductor laser beam with a long wavelength (especially 750 nm or more) as an exposure light source and a corresponding carrier-generating substance (especially (by reversal development).

The copolymer of the present invention used for the intermediate layer in the photoreceptor of the present invention has the following general formula [! ] α,β-unsaturated substituted or unsubstituted ethylenic hydrocarbon represented by
It is preferable to use monomer).

General formula [I]: R'R' (However, R1, R1SR3, R4 have a carbon atom number of 1 to IO
is an alkyl group or a hydrogen atom. ) According to the present invention, this monomer is an acrylic ester and/or a methacrylic ester (both as ester-forming groups).
Examples include alkyl groups having 1 to 10 carbon atoms. ), but the proportion of the above ester in this copolymer is preferably 5 to 50% by weight (total amount when both esters are used together) of the total (100% by weight); It is more desirable to set the proportion to 20 to 40% by weight. If the proportion of ester is large, the effects of containing the copolymer (film adhesion to the base, reduction of image defects, resistance to CGL solvent solubility) tend to decrease, and the proportion of ester If the amount is small, the deterioration of the blocking function among the above effects will be significant.

Furthermore, this copolymer preferably contains maleic anhydride and/or maleic acid in an amount of 0 to 25% by weight (total amount when both maleic acids are used together) as the third copolymerization component. This further improves the effectiveness of the copolymer.

In the case of the ternary I copolymer, the proportions of each component are 35 to 95% by weight of the above ethylene hydrocarbon and 5 to 95% by weight of the above ester.
50% by weight, and the above (anhydrous) maleic acid O is preferably 25% by weight.

The photoconductive substance used in the intermediate layer may include inorganic pigments such as insulating titanium oxide, conductive titanium oxide, zinc oxide, tin oxide, and antimony oxide, organic pigments such as polycyclic quinone, perylene, etc. Both inorganic and organic pigments are mentioned.

For example, the polycyclic quinone system may be of the following general formula.

(1) General formula of anthorone pigment [■]: (2) General formula of dibenzpyrenequinone pigment [■]: (3) and general formula of lanthrone pigment [■]: In the above, X: halogen atom, nitro group, cyan group, acyl group, or carboxyl group.

n=o~4 m=0~6 The above pigment for the intermediate layer generally has a particle size of 0.01 to 0.05 μm, and is mainly composed of the above-mentioned copolymer of the present invention or the same. A polymer is used as a binder, and the intermediate layer is dispersed in a state bound by the binder. In this case, the ratio of pigment to binder (however, the copolymer of the present invention or a mixture of this and other binders) is
Binder The ratio is preferably 1/10 to 10/1 (weight ratio). Further, as a method for dispersing the pigment, for example, sand grinder dispersion (24 hours) may be employed.

Further, it is desirable that the intermediate layer has a thickness of 0.1 to 30 μm in order to exhibit the above-mentioned effects and to maintain good photoreceptor performance. The film thickness is preferably 1 to 10 μm.

The photoreceptor of the present invention has the structure shown in FIG. 1, for example.

In this photoreceptor, on a conductive support (substrate) 1,
A carrier generation layer 6 is provided via the above-mentioned intermediate layer 7, and a carrier transport N4 is provided on this carrier generation layer 6. 8 indicates a photosensitive layer. Therefore, since the intermediate layer 7 is provided between the carrier generation layer 6 and the support 1,
While the injection of holes from the support side as described in FIG. 4 is effectively prevented, electrons, which are photocarriers, can be efficiently transported to the support side during light irradiation. Note that such an intermediate layer may be provided between the carrier generation layer and the carrier transport layer.

Further, in the photoreceptor of the present invention, a protective layer (protective film) may be formed on the surface of the photoreceptor to improve printing durability, for example, a synthetic resin film may be coated. In this case, the intermediate layer may be provided below the protective layer. Further, a conventionally known subbing layer (having a very thin film thickness of 1 μm or less) may be provided immediately above the conductive support.

In addition to the above-described structure (that is, a carrier transport layer is laminated on a carrier-generating layer), the photoreceptor of the present invention may also have a single-layer photosensitive layer in which a carrier-generating substance and a carrier-transporting substance are mixed. good.

Next, the general formula of the carrier-generating substance used in the photosensitive layer of the present invention is shown.

1. Azo pigment general formula [V]: x'-N-N-! -N-N-x' General formula [■]: phenyl group-containing hydrocarbon group.

X', x': coupler formula (■) (in the formula, : Hydrogen atom, hydroxy group, carboxyl group or its ester group, sulfo group, substituted/unsubstituted carbamoyl group or substituted/unsubstituted sulfamoyl group RS; Hydrogen atom, substituted/unsubstituted alkyl group, substituted/unsubstituted Amino group, substituted/unsubstituted carbamoyl group, carboxyl group or ester group thereof, or cyano group Ar: substituted/unsubstituted aryl group RS, substituted/unsubstituted alkyl group, substituted/unsubstituted aralkyl group, or ? i!IQ・end!1A represents an aryl group,) (wherein, Ar' is a benzene ring,
An aromatic ring such as a naphthalene ring, a hetero ring such as a dibenzofuran ring, or a substituted product thereof; Ar" and Ar" are an aromatic ring such as a benzene ring or a naphthalene ring, or a substituted product thereof;
R? and R9 represents hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof, and R1 represents a lower alkyl group, a carboxyl group, or an ester thereof. 2. In the phthalocyanine pigment α-2β-1χ-1τ-type carrier generation layer, the content ratio of the carrier generation substance to the binder substance is preferably 3/1 to 1/10, and 3/1 to 1/3. It is even more preferable to do so.

When the content ratio of the carrier-generating substance is larger than the above range, black spots and the like are likely to appear. However, if the proportion of the carrier-generating substance is too small, the photosensitivity and the like will be rather reduced.

The thickness of the carrier generation layer is preferably 0.1 μm or more, more preferably within the range of 0.2 to 5 μm, and the thickness of the carrier transport layer is preferably 10 μm or more.

The thickness of the entire photosensitive layer is preferably within the range of 10 to 40 μIl, and more preferably within the range of 15 to 30 μm. If the film thickness is smaller than the above range, the charging potential will be low due to the thinness, and the printing durability will also tend to decrease. Furthermore, if the film thickness is larger than the above range, the residual potential will increase on the contrary, and the same phenomenon as described above will occur when the carrier generation layer is too thick, making it difficult to obtain sufficient transport performance. Therefore, the residual potential tends to increase during repeated use.

It is also possible to include a carrier transport substance in the carrier generation layer.

When a photosensitive layer or an intermediate layer is formed by dispersing a particulate carrier-generating substance or a photoconductive substance, the substance has an average particle size of 2 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less. It is preferable that it is made into powder or granular material.

Furthermore, in the carrier transport layer, the carrier transport substance is
Those having excellent compatibility with the binder substance are preferred.

As a result, turbidity and opacity do not occur even if the amount of the binder substance is increased, so the mixing ratio with the binder substance can be set at a very wide range. The layer is uniform and stable, resulting in better sensitivity and charging characteristics.
Furthermore, a photoreceptor that can form clear images with high sensitivity can be obtained.

Furthermore, especially when used in repeated transfer type electrophotography, it is possible to achieve the effect that fatigue deterioration is less likely to occur.

In the present invention, it is also possible to use one or more other substances in combination with the carrier-generating substance or photoconductive substance described above. Examples of carrier-generating substances or photoconductive substances that can be used in combination include anthraquinone pigments, perylene pigments, polycyclic quinone pigments, methine squaric acid pigments, cyanine dyes, and azulenium compounds.

Carrier transport substances that can be used in the present invention include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidasilone derivatives, imidazolidine derivatives, bisimidazolidine derivatives,
Styryl compounds, hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, poly- N-
Vinyl carbazole, poly-1-vinylpyrene, poly-
It may be one or more selected from 9-vinylanthracene and the like.

Specific examples of such carrier transport substances are disclosed in Japanese Patent Application No. 1983.
-195881. The general formula is listed below.

The following general formula (IX) or [X
] styryl compounds can be used.

General formula [■]: (However, in this general formula, R11, RIs represents a substituted or unsubstituted alkyl group, aryl group, and substituents include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, Use an aryl group.

Ar', Ar& represents a disubstituted or unsubstituted aryl group, and the substituents include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, and an aryl group.

RI3 and R14 represent a substituted or unsubstituted aryl group or a hydrogen atom, and as a substituent, an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, or an aryl group is used. ) General formula [X]: RIs (However, in this general formula, RIs: substituted or unsubstituted aryl group, R111,
Hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkoxy group, amine group, substituted amino group, hydroxyl group, R17: represents a substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic group. ) In addition, the following general formula (XI), (
It is also possible to use hydrazone compounds of XI), (XIa), (XIb) or (XIVI).

General formula (XI): (However, in this general formula, RIM and RlI each represent a hydrogen atom or a halogen atom, Rto and RlI each represent a substituted or unsubstituted aryl group, Ar': a substituted or unsubstituted arylene group ,) General formula (XI): (However, in this general formula, R12 represents a substituted or unsubstituted aryl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted heterocyclic group, Rts, R14 and Rus: represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group) General formula (XIa)? R1? (However, in this general formula, Rg&: methyl group, ethyl group, 2-hydroxyethyl group, or 2-chloroethyl group, R87: methyl group, ethyl group, benzyl group, or phenyl group, R2I: methyl group, ethyl group, benzyl group) or phenyl group.

General formula (Xl[b): (However, in this general formula, R19 is a substituted or unsubstituted naphthyl group, Rzo is a substituted or unsubstituted alkyl group, aralkyl group, or aryl group; R31 is a hydrogen atom, an alkyl group, or Alkoxy group; RlI and R33 are the same or different groups consisting of a substituted or unsubstituted alkyl group, aralkyl group or aryl group) (However, in this general formula, R34: a substituted or unsubstituted aryl group or Substituted or unsubstituted heterocyclic group, R31: hydrogen atom, substituted or unsubstituted alkyl group, or substituted or unsubstituted aryl group, Q: hydrogen atom, halogen atom, alkyl group, substituted amino group, alkoxy group, or cyano group , s: represents an integer of 0 or 1) Furthermore, a pyrazoline compound represented by the following general formula (XV) can also be used as a carrier transport substance.

General formula (xv): [However, in this general formula, l: 0 or 1, R'' and R3?, substituted or unsubstituted aryl group, R38: substituted or unsubstituted aryl group, aromatic or heterocyclic group, R39 and R40, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group or aralkyl group (provided that Rco9 and Ra.

are not both hydrogen atoms, and when 2 is 0, R19 is not a hydrogen atom. )] Furthermore, an amine derivative of the following general formula (XVI) can also be used as a carrier transport substance.

General formula (XVI): Ar'' (However, in this general formula, Ar'', Ar'': represents a substituted or unsubstituted phenyl group, and a halogen atom, an alkyl group, a nitro group, or an alkoxy group is used as a substituent. .

A r '°: represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, fluorenyl group, or heterocyclic group, and substituents include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group, an aryl group, Amino groups, nitro groups, piperidino groups, morpholino groups, naphthyl groups, anthryl groups and substituted amino groups are used. However, an acyl group, alkyl group, aryl group, or aralkyl group is used as a substituent for the substituted amino group. ) Furthermore, a compound represented by the following general formula (XVX) can also be used as a carrier transport substance.

General formula (xvm): R441(" (However, in this general formula, Ar": represents a substituted or unsubstituted arylene group, R41, R"% R" and R44: substituted or unsubstituted alkyl group, substituted or It represents an unsubstituted aryl group or a substituted or unsubstituted aralkyl group.) Furthermore, a compound of the following general formula (x v m) can also be used as a carrier transport substance.

General formula (XVI): [However, in this general formula, R4S, R46, R4? and R
411 is a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, a benzyl group, or an aralkyl group; R49 and Rso are each a hydrogen atom, a substituted or unsubstituted group having 1 to 1 carbon atoms; 40 alkyl groups, cycloalkyl groups, alkenyl groups, cycloalkenyl groups, aryl groups or aralkyl groups (provided that R'' and Rso jointly have 3 to 10 carbon atoms)
may form a saturated or unsaturated hydrocarbon ring.

) R51, R'Jt, R51 and R54 are each a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an amino group, an alkyl group. It is an amino group or an arylamino group. ] An antioxidant can be contained in the carrier transport layer and the carrier generation layer. This can suppress the influence of ozone generated during discharge, and can prevent an increase in residual potential and a decrease in charged potential during repeated use.

Examples of the antioxidant include hindered phenol, hindered amine, paraphenylene diamine, aryl alkane, hydroquinone, spirochroman, spiroindanone and derivatives thereof, organic sulfur compounds, f-organic phosphorus compounds, and the like.

These specific compounds are disclosed in Japanese Patent Application No. 61-1628.
No. 66, No. 61-188975, No. 61-19587
No. 8, No. 61-157644, No. 61-195879
No. 61-162867, No. 61-204469, No. 61-217493, No. 61-217492, and No. 61-221541.

A polymeric organic semiconductor can also be included in the photosensitive layer.

Among these polymeric organic semiconductors, poly-N-vinylcarbazole or its derivatives are highly effective and are preferably used. Such poly-N-vinylcarbazole derivatives are those in which all or part of the carbazole ring in the repeating unit is substituted with various substituents, such as an alkyl group, a nitro group, an amino group, a hydroxy group, or a halogen atom. .

Furthermore, at least one type of electron-accepting substance can be contained in the photosensitive layer for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, and the like.

Electron-accepting substances that can be used in the photoreceptor of the present invention include:
For example, succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, 4
-Nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, O-dinitrobenzene, m-dinitrobenzene,
1.3.5-) IJ nitrobenzene, varanitrobenzonitrile, picryl chloride, quinone chlorimide,
Chloranil, pullmanil, 2-methylnaphthoquinone, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-
Fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene [dicyanomethylenemalonodinitrile], picric acid, 0-nitrobenzoic acid, p-nitrobenzoic acid, 3.5-dinitrobenzoic acid , pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds with high electron affinity. Among these, fluorenone series, quinone series, and benzene derivatives having electron-withdrawing substituents such as C1, CN, and Not are particularly preferred.

Furthermore, silicone oil or a fluorine-based surfactant may be present as a surface modifier. Further, an ammonium compound may be contained as a durability improver.

Furthermore, an ultraviolet absorber may be used.

Preferred ultraviolet absorbers include benzoic acid, stilbene compounds and derivatives thereof, triazole compounds, imidazole compounds, triazine compounds, coumarin compounds,
Nitrogen-containing compounds such as oxadiazole compounds, thia, zole compounds, and their derivatives are used.

In addition to the copolymers of the present invention described above for the intermediate layer, examples of binder resins that can be used in the constituent layers of the photoreceptor include polyethylene, polypropylene, acrylic resins, methacrylic resins, vinyl chloride resins, vinyl acetate resins, and epoxy resins. , polyurethane resins, polyester resins, alkyd resins, polycarbonate resins, melamine resins, methacrylic resins, acrylic resins, polyvinylidene chloride, polystyrene, addition polymerization resins, polyaddition resins, polycondensation resins, and their repeating units. copolymer resins containing two or more, insulating resins such as vinyl chloride-vinyl acetate copolymer resins, styrene-butadiene copolymer resins, vinylidene chloride-acrylonitrile copolymer resins, and further N-vinylcarbazole, etc. Examples include polymeric organic semiconductors, modified silicone resins, and the like.

The above binders can be used alone or as a mixture of two or more.

As a binder for the protective layer provided as necessary,
Volume resistance 108Ω・1 or more, preferably 10′6Ω・c
A transparent resin having a resistance of 1013 Ω·cm or more is used, more preferably 10 13 Ω·cm or more. Further, the binder may be a resin that is cured by light or heat, and examples of the resin that is cured by light or heat include thermosetting acrylic resin, epoxy resin, urethane resin, urea resin, polyester resin, alkyd resin, Examples include melamine resins, photocurable cinnamic acid resins, and copolymerized or condensed resins thereof, as well as all other photocurable or thermosetting resins used in electrophotographic materials. In addition, the protective layer contains improvements in processability and physical properties (
If necessary, a thermoplastic resin may be contained in an amount of less than 50% by weight for the purpose of preventing cracks, imparting flexibility, etc.).

Such thermoplastic resins include, for example, polypropylene,
Acrylic resins, methacrylic resins, vinyl chloride resins, vinyl acetate resins, epoxy resins, polycarbonate resins or copolymer resins thereof, polymeric organic semiconductors such as poly-N-vinylcarbazole, and other thermoplastic resins used in electrophotographic materials All of them are used.

The carrier generation layer can be provided by the following method (the same applies to the intermediate layer).

(a) A method in which a binder and a solvent are added to a carrier-generating substance, mixed and dissolved, and a solution is applied.

(b) A method in which a carrier-generating substance, etc. is made into fine particles in a dispersion medium using a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor, etc., and a binder is added, mixed and dispersed, and the resulting dispersion is applied.

Dispersing the particles under the action of ultrasound in these methods allows for homogeneous dispersion.

Further, the carrier transport layer can be formed by applying and drying the above-mentioned carrier transport substance alone or by dissolving and dispersing it together with the above-mentioned binder resin.

In this case, when a carrier transport substance is contained in the carrier generation layer, the carrier transport substance is dissolved or dispersed in the solution (a) or the dispersion liquid (b) in advance, that is, in the carrier generation layer. There is a method of adding a carrier transport substance. In this case, it is preferable that the amount of the carrier transport substance added is within the range of 1 to 100 parts by weight based on 100 parts by weight of the binder, and a solution containing the carrier transport substance is applied onto the carrier generation layer, There is a method in which the carrier generation layer is swollen or partially dissolved to diffuse the carrier transport substance into the carrier generation layer.

When this method is adopted, it is not necessary to add a carrier transport substance to the carrier generation layer as described above;
There is no problem in performing the above three methods at the same time.

As the solvent or dispersion medium used for forming the layer, n
-butylamine, diethylamine, ethylenediamine,
Impropaturamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, dichloromethane, tetrahydrofuran,
Dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide and the like can be mentioned.

The photosensitive layer, intermediate layer, protective layer, etc. can be provided by, for example, blade coating, dip coating, spray coating, roll coating, spiral coating, or the like.

The conductive support is prepared by coating, vapor depositing, laminating, or the like a conductive thin layer made of a metal plate, metal drum, or a conductive polymer, a conductive compound such as indium oxide, or a metal such as aluminum, palladium, or gold. Those provided on a substrate such as paper or plastic film are used.

Next, an example of a recording apparatus using the photoreceptor of the present invention is shown in FIG. 2, and FIG. 4 is a flowchart of a reversal development method in electrophotography.

In the apparatus shown in FIG. 2, 23 is a drum-shaped image carrier which has the photosensitive layer 8 and intermediate layer 7 made of the above-mentioned organic photoconductive material and rotates in the direction of the arrow; 24 is an image exposure device, and 15 is a developing device.

20 transfers the toner image formed on the image carrier 23 to the recording medium P;

21 is a transfer device; 19 is a corona discharger for separation; 12 is a pre-transfer exposure lamp provided as necessary to facilitate
is a fixing device that fixes the toner image transferred to the recording medium P. Reference numeral 13 has a static eliminator consisting of one or a combination of a static eliminator lamp and a corona discharger for static elimination, and 14 has a cleaning blade or a fur brush for removing residual toner on the surface of the image carrier 23 after the image has been transferred. It is a cleaning device.

When the image exposure is performed using a semiconductor laser, the image exposure 24 is preferably performed using a laser beam scanner in the case of a recording apparatus using a drum-shaped image carrier 23 like the recording apparatus shown in FIG.

Further, in a recording apparatus in which the image carrier can take a flat state such as a belt shape, the image exposure can be a flash exposure.

The method shown in FIG. 3 can be carried out using the recording apparatus as described above.

Figure 3 shows that an electrostatic image is formed by an electrostatic image forming method in which the image exposure area has a lower potential than the background area, and development is performed using toner that is charged to the same polarity as the background area potential. This figure shows an example of reversal development performed by the adhesion of . That is, first, the static electricity is removed by the static eliminator 13, and then the cleaning device 1
The surface of the image carrier 23 in the initial state, which has been cleaned in step 4 and has a potential of O, is uniformly charged by the charger 22, and an image exposure 24 is projected onto the charged surface to form an electrostatic image area. Image exposure is performed such that the potential of is approximately 0, and the obtained electrostatic image is developed by a developing device 15 (toner T).

Note that this image forming method uses halogen lamps, tungsten lamps, LEDs (light emitting diodes), and helium lamps.
It can be applied to various light sources such as neon, argon, helium-cadmium gas lasers, and semiconductor lasers.

The image forming method of the present invention has a wide variety of applications such as electrophotographic copying machines and printers.

E. Examples Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited thereby, and of course includes other embodiments with various modifications.

First, photoreceptors AE of Examples and photoreceptors a''-c of Comparative Examples were manufactured in the following manner.

The manufacturing procedure for each photoreceptor is common as follows.

Diameter 80ais+, length 355mm, wall thickness IIIl
The 4th A is an aluminum cylinder with a mirror-finished surface.
It was produced by the method shown in Fig. 4B. The sample was immersed in a solution, and dip coating was performed at a pulling rate of 200 an/'win. After coating, it was dried at 40°C for 30 minutes to form an intermediate layer with a predetermined thickness.

Next, rFa manufactured by Dainippon Ink Co., Ltd. as a carrier generating substance
Stogen Blue 7120 BJ 20g,
Methyl ethyl ketone solution 2 in which 20 g of modified Si resin rKR-5240J (manufactured by Toray Silicone) was dissolved.
In addition to 0OOI11, the mixture was dispersed in a sand grinder for 4 hours to prepare a carrier generation layer coating solution. The cylinder having the above intermediate layer was immersed in this solution for 15 minutes.
Pull it up at a speed of
A carrier generation layer having a thickness of II was obtained.

Furthermore, 300 g of a carrier transport material having the following structure and polycarbonate resin "Panlite 11300J (Kijin Kasei) 400
Dissolve g in 2.000-1,2-dichloroethane,
The cylinder coated up to the carrier generation layer was immersed in the obtained solution, pulled up at a pulling rate of 90 ml/sin to perform dip coating, and dried at 85° C. for 1 hour to form a carrier transport layer having a film thickness of 20 μm. ' was formed.

Photoreceptors A-E according to the present invention and photoreceptors a- of comparative examples
rU-Bix 1550J for each of the 8 types of c.
(Manufactured by Nika Corporation) (equipped with a semiconductor laser light source) installed in a modified machine, adjust the grid voltage so that the voltage is 1700 ± 10 (Vl), and perform reverse development with a developing bias of -600 (V). The black spots on the white background and the moiré on the black background of the copied image were evaluated.

The evaluation of Kuropochi was performed using an image analysis device [Omnicon 30].
The particle size and number of black dots were measured using a "Type 00" (manufactured by Shimadzu Corporation), and the number of black dots with a diameter of 0.05 m5 or more was determined based on the number of black dots per CD. The criteria for black spot evaluation are as shown in the table below.

Note that if the black spot determination result is ◎ or O, it is practical, but Δ may not be suitable for practical use, and if it is ×, it is not suitable for practical use. Regarding moire, ◎ indicates no moire, O indicates not much moire, and × indicates frequent moire.

In addition, regarding the film adhesion of the obtained photoreceptor, we conducted a substrate visual test, and as a result, the 01 film was completely lifted when there was no peeling of the film when visually observed. The ones that are present are marked as ×.

FIG. 5 shows the evaluation results of Examples and Comparative Examples.

According to the results, by providing the intermediate layer according to the present invention, electrophotographic properties such as charging, sensitivity, residual potential, repeated potential stability, and characteristic fluctuations due to environmental changes are improved, and black Spots and moire are greatly reduced, and film adhesion is also improved.

[Brief explanation of the drawing]

1 to 5 show embodiments of the present invention, in which FIG. 1 is a cross-sectional view of a portion of a photoreceptor used in the present invention, FIG. 2 is a schematic diagram of an image forming apparatus, and FIG. The figure is a flowchart showing the process of image formation, Figure 4A and Day 4 are tables summarizing the manufacturing methods of each photoreceptor, and Figure 5 is a table comparing the characteristics of each photoreceptor. . FIG. 6 is a sectional view of a portion of a conventional photoreceptor. In addition, in the reference numerals shown in the drawings, 1... Conductive substrate 4... Carrier transport layer 6... Carrier generation layer 7... . . . Intermediate layer 8 . . . Photosensitive layer. Agent Patent Attorney Hiroshi Tsuita Figure 1 Figure 2 Figure 3 Figure 6

Claims (1)

[Claims] 1. In a photoreceptor in which a photosensitive layer and an intermediate layer are provided on a conductive support, a copolymer containing a substituted or unsubstituted ethylene hydrocarbon and an acrylic acid ester and/or a methacrylic acid ester as a copolymerization component and a photoconductive material that is substantially insensitive to imagewise exposure light is contained in the intermediate layer.