JPH01289965A - Photosensitive body - Google Patents

Abstract

PURPOSE:To prevent defect in picture image such as black spots without impairing performance of a photosensitive body by constituting a blocking layer of a copolymer consisting of a (non)substituted ethylenic hydrocarbon and acrylic acid and/or methacrylic acid as copolymer components. CONSTITUTION:In a photosensitive body provided with a blocking layer and a photosensitive layer contg. an org. photoconductive material on an electroconductive base body, it is very important that a blocking layer (or an undercoating layer) is constituted of a copolymer consisting of a (non) substituted ethylenic hydrocarbon and acrylic acid and/or methacrylic acid as copolymer components. Namely, such copolymer has a function for effectively preventing ununiform injection of hall from a base body which may happen liably when an org. photoconductive material having great hall mobility is used for the photosensitive layer. Moreover, since the copolymer has high adhesion to an underground and can be coated uniformly, the blocking function can be exhibited satisfactorily. Thus, a picture image having high quality contg. no defect such as black spots on the picture image is obtd.

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 attached lubricants and 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. 9 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 greater than that of electrons when negatively charged, a photoconductive material having good hole transport properties can be used, which is advantageous in terms of photosensitivity and the like.

However, in such photoreceptors, especially in photoreceptors using organic photoconductive substances, non-uniform carrier (hole) injection from the conductive substrate or lower layer side tends to occur when negatively charged, as shown in FIG. Therefore, the surface charge disappears or decreases when viewed microscopically. This is especially
A black spot-like image defect in the reversal development method (black spot) that significantly reduces the quality of the image.

This problem of black spots does not occur with inorganic photoconductive materials (for example, Zn0) that have low ball mobility.
This phenomenon is unique to photoreceptors that use organic photoconductive materials with high hole mobility.

The reason for this is thought to be that the carrier injection described above occurs non-uniformly.

Therefore, it has been proposed to provide a blocking layer between the conductive substrate 1 and the photosensitive layer. Materials constituting the blocking layer include aluminum oxide, aluminum hydroxide, titanium oxide, tin oxide, zinc oxide, etc. alone or a binder-containing layer, polyvinyl alcohol, casein,
Resins such as polyamide, polyurethane, and cellulose are known.

However, the above-mentioned known blocking layer does not have a sufficient effect of suppressing black spots. However, it has not been achieved to improve both the blocking property and the sensitivity as a photoreceptor. For example, in the case of aluminum, etc., oxidation occurs simply by leaving it in the air, but such oxidation occurs in a non-uniform state depending on the location, and often lacks homogeneity due to impurities and the like. Therefore, in the known techniques, the blocking layer cannot be provided uniformly, and therefore the blocking performance cannot be fully exhibited. The same problem occurs when a resin is used for the blocking layer, and not only is the resin layer not uniformly coated (formation of precipitates), but the resin layer easily dissolves when coating the upper layer, such as a carrier generation layer. There is.

Among the resins conventionally used, those that are thought to have effective blocking properties have poor solubility and have problems with precipitation.
Moreover, it impairs the electrophotographic properties, and conversely, if you try to suppress the precipitation, it will dissolve when applying the carrier generation layer, resulting in non-uniformity.
Does not function well as a blocking layer.

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-
A! -As) type light emitting element has an oscillation wavelength of about 750 nm 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 An object of the present invention is to provide a photoreceptor that can suppress image defects such as black spots without impairing photoreceptor performance (especially electrophotographic characteristics).

20 Structure of the invention and its effects, that is, the present invention provides a photoreceptor in which a blocking layer and a photosensitive layer containing an organic photoconductive substance are provided on a conductive support. The present invention relates to a photoreceptor characterized in that the blocking layer is formed of a copolymer containing a hydrocarbon and acrylic acid and/or methacrylic acid as copolymer components.

According to the present invention, the blocking layer (or undercoat layer) provided on the support is formed of a copolymer containing substituted or unsubstituted ethylene hydrocarbon and acrylic acid and/or methacrylic acid as copolymer components. It is extremely important that the That is, as mentioned above, this copolymer (hereinafter referred to as the copolymer of the present invention) is free from the damage from the support that tends to occur when an organic photoconductive substance with high hole mobility is used in the photosensitive layer. It has a blocking function that effectively prevents uneven injection of balls, and it has good adhesion to the base and can be formed uniformly, so it can fully demonstrate its blocking function. can.

In particular, no precipitates are generated when the blocking layer is coated, and the resin of the blocking layer is not eluted when the upper layer is coated.

Therefore, it is considered that the presence of this blocking layer can provide a barrier against local carrier injection from the supporting side, and can prevent the 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.

In this blocking layer, if the above-mentioned copolymer component consists only of substituted or unsubstituted ethylene hydrocarbon (in this case, it becomes a homopolymer), the adhesion to the base will not be sufficient, but the acrylic acid and/or
Alternatively, since methacrylic acid is copolymerized as a copolymerization component, the adhesion to the base (film attachment) is improved.

Furthermore, since the photoreceptor of the present invention has the above-mentioned excellent blocking layer, an image can be formed using a semiconductor laser beam with a long wavelength (particularly 750 nm or more) as a light source and a corresponding carrier-generating substance ( (Especially by reversal development.)
It is suitable for

The copolymer of the present invention used for the blocking layer in the photoreceptor of the present invention is represented by the following general formula (I).
- It is desirable to use an unsaturated substituted or unsubstituted ethylene hydrocarbon as the copolymerization component (monomer).

General formula [■]: (However, R1, R2, R3, and R4 have 1 to 10 carbon atoms.
is an alkyl group or a hydrogen atom. ) This monomer is copolymerized with acrylic acid and/or methacrylic acid according to the present invention, and in this copolymer, the above-mentioned acrylic acid and/or methacrylic acid are copolymerized.
Or the proportion occupied by methacrylic acid is the whole (100% by weight)
The amount is preferably 5 to 50% by weight (the total amount when both acids are used together), and more preferably 20 to 40% by weight. If the proportion of acrylic acid and/or methacrylic acid is small, the effects of containing the copolymer (film formation, reduction of image defects, CGL (carrier generation layer) coating properties tend to decrease, and the proportion of acrylic acid and/or methacrylic acid tends to decrease. If there is a large amount of
Melt flow rate according to 6730-1981) is 2~
It is preferable to set it to 500 g/10 m1n.

Furthermore, this copolymer preferably contains maleic anhydride and/or maleic acid in an amount of 0 to 20% by weight (total amount when both maleic acids are used together) as the third copolymerization component. This further improves the effectiveness of the copolymer.

The content is preferably 20% by weight.

It is desirable that the blocking layer in the present invention has a thin film thickness of 1 μm or less in order to sufficiently exhibit blocking performance while maintaining good photoreceptor performance such as suppression of residual potential.

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

In this photoreceptor, on the conductive support (substrate) ■,
A carrier generation layer 6 is provided through the blocking layer 7 described above, and a carrier transport layer 4 is provided on this carrier generation layer 6.
is provided. 8 indicates a photosensitive layer. Therefore,
A blocking layer 7 is provided between the carrier generation layer 6 and the support l.
9, it is possible to effectively prevent non-uniform injection of balls from the support side as described in FIG. can.

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 has a single-layer structure in which a carrier-generating substance and a carrier-transporting substance are mixed, as shown in FIG. It may also consist of a photosensitive layer 8. Also,
As shown in FIG. 5, a carrier generation layer 6 and a carrier transport layer 4
It is also possible to have a layer structure in which the layers are upside down (for positive charging).

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.

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

1. Polycyclic guinone pigment (1) Anthoanthrone pigment general formula [■]: (2) Dihenspyrenequinone pigment general formula [■]: (3) Pyranthrone pigment general formula [■]; In the above, X: halogen atom , nitro group, cyano group, acyl group, or carboxyl group.

n=Q~4 m=o~6 2. Azo pigment general formula [■]: X'-N=N-A'-N=N-X'' general formula [■]
]: X'-N=N-A-N=N-A-N=N-X "In the above, A, A': substituted or unsubstituted divalent phenyl group-containing hydrocarbon group X', X" : Kabra-3, phthalocyanine pigment α-3β-1χ-1τ-1ε-type carrier generation layer, the content ratio of the carrier generation substance to the binder substance is preferably 5/1 to 1/10, and 3/1. It is more preferable to set it to 1/3. When the content ratio of the carrier-generating substance is larger than the above range, black spots and the like tend to appear.

However, if the proportion of gear-generating substances 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, and more preferably within the range of 0.2 to 5 μm. 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 μm, 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, during repeated use, the residual potential tends to increase.

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

When a photosensitive layer is formed by dispersing a granular carrier-generating substance, the carrier-generating substance is in the form of powder with an average particle size of 2 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less. is preferred.

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 generation layer is uniform and stable, resulting in better sensitivity and charging characteristics.
Furthermore, it is possible to use a photoreceptor that can form clear images with high sensitivity.

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

Carrier transport substances that can be used in the present invention include carbazole derivatives, oxadiazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, l-lyazole derivatives, imidazole derivatives, imidacilone derivatives, imidapridine derivatives, bisimidazolidine derivatives, styryl compounds, Hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, hendithiazole derivatives, hendzimidazole derivatives, quinazoline derivatives, hensifuran derivatives, acridine derivatives, phenazine derivatives, aminostilhene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilhene derivatives, poly-N
- It may be one or more selected from vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc.

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 [■] or [■] as a carrier transport substance
styryl compounds can be used.

General formula [■]: (However, in this general formula, R'', R12 represents a substituted or unsubstituted alkyl group or aryl group, and substituents include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, and a halogen atom. , using an aryl group.

Ar5, Ar6: Represents a substituted or unsubstituted aryl group, and the substituent used is an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, or an aryl group.

R13, RI4. It represents 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 [■] : (However, in this general formula, R15: substituted or unsubstituted aryl group, RI6 = hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkoxy group, amine group, substituted amine group , hydroxyl group, R'': substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic group.) In addition, as gear transport substances, the following general formulas [■], (X
), (Xa 'l, (Xb ) or (XI) can also be used.

General formula (IX) (However, in this general formula, RII+ and R19 each represent a hydrogen atom or a halogen atom, RZo and RZI each represent a substituted or unsubstituted aryl group, and Ar7: a substituted or unsubstituted arylene group. ) General formula [Xa: (However, in this general formula, R22 represents a substituted or unsubstituted aryl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted heterocyclic group, R21, R'' and R25 : Represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.) General formula (Xa): R'' (However, in this general formula, R26: methyl group, ethyl group , 2-hydroxyethyl group or 2-chloroethyl group, R27: methyl group, ethyl group, hensyl group or phenyl group, R28: methyl group, ethyl group, hensyl group or phenyl group.

General formula (Xb): (However, in this general formula, R'' is a substituted or unsubstituted naphthyl group; R30 is a substituted or unsubstituted alkyl group, aralkyl group, or aryl group; R'' is a hydrogen atom, Alkyl group or alkoxy group; R32 and R33 are the same or different groups consisting of a substituted or unsubstituted alkyl group, aralkyl group or aryl group.) General formula [X■]: (However, this general formula Among them, R34: substituted or unsubstituted aryl group or substituted or unsubstituted heterocyclic group, R35: hydrogen atom, substituted or unsubstituted alkyl group, or substituted or substituted aryl group, Q: hydrogen atom, halogen atom , a furkyl group, a substituted amino group, an alkoxy group, or a cyano group, S: represents an integer of 0 or 1.) In addition, as a carrier transport substance, the following general formula CXII)
Birapurin compounds can also be used.

General formula (XI): HR'' R36-C-C-H I [However, in this general formula, l: 0 or 1, R36 and R37: substituted or unsubstituted aryl group, R30: substituted or unsubstituted aryl group or heterocyclic group, R39 and R': hydrogen atom, alkyl group having 1 to 4 carbon atoms, or substituted or unsubstituted aryl group or aralkyl group (however, R39 and R'' are both hydrogen atoms (In addition, when l is 0, R39 is not a hydrogen atom.) Furthermore, an amine derivative of the following general formula (Xlll) can also be used as a carrier transport substance.

General formula CXI): (In this general formula, Ar', Ar9: 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.

Ar”: 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, and an amino group. , a nitro group, a piperidino group, a morpholino group, a naphthyl group, an anthryl group, and a substituted amine group. However, as a substituent for the substituted amino group, an acyl group, an alkyl group, an aralkyl group, and an aralkyl group are used. , a compound of the following general formula [XIV] can also be used as a carrier transport substance.

General formula CXIV): R''N Arm N R42 R44R43 (However, in this general formula, Ar'': represents a substituted or unsubstituted arylene group, R'', RI12, R'' and R'': substituted or unsubstituted represents an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group) Furthermore, a compound of the following general formula CXV) can also be used as a carrier transport substance.

General formula CXV'J: [However, in this general formula, R4S, R'', R47 and R'' are each a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an alkenyl group, Hensyl group or aralkyl group, R49 and R5O are each a hydrogen atom, a substituted or unsubstituted carbon atom number of 1 to 40
alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, aryl group or aralkyl group (however, R
49 and R5O may jointly form a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms. ) R5I, R52, R53 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 aral group, an aralkyl group, an alkoxy group, an amino group, It is an alkylamino 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, alkane, hydroquinone, spirochroman, spirodanone and derivatives thereof, organic sulfur compounds, 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. 61-1.62867, 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 mean that all or a part of the carbazole ring in the repeating unit has various substituents, such as an alkyl group,
It is substituted with four groups, 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, tetrabromophthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, 4
-21-B Phthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzoic acid, m-dinitrobenzoic acid, 1.3.5-t'J nitrohenzene , varanitrohendinitrile, vicryl chloride, quinone chlorimide, chloranil, brumanil, 2-methylnaphthoquinone,
dichlorodicyanobara benzoquinone, anthraquinone,
Dinitroanthraquinone, trinitrofluorenone, 9
-Fluorenylidene-[cysoanomethylenemalonodinitrile], polynitro-9-fluorenylidene-[dicyanomethylenemalonodinitrile], picric acid, 0-nitrobenzoic acid, p-21-benzoic acid, 3,5- Examples include dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrobenzoic acid, phthalic acid, mellitic acid, and other compounds with high electron affinity. Among these, fluorenone series, detenone series, and Hensen derivatives having electron-withdrawing substituents such as CI, CN, and NO2 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 nitrogen-containing compounds such as benzoic acid, stilchen compounds and derivatives thereof, triazole compounds, imidazole compounds, triazine compounds, coumarin compounds, oxadiazole compounds, thiazole compounds and derivatives thereof.

Examples of binder resins that can be used in the constituent layers of the photoreceptor include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, polyester resin, alkyd resin, polycarbonate resin, and melamine resin. , methacrylic resin, acrylic resin, addition polymerization type resin such as polyvinylidene chloride, polystyrene, polyaddition type resin, polycondensation type resin, copolymer resin containing two or more of these repeating units, vinyl chloride-vinyl acetate Insulating resins such as copolymer resins, styrene-butadiene copolymer resins,
Examples include vinylidene chloride-acrylonitrile copolymer resins, polymeric organic semiconductors such as N-vinyl hardened resin, 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・cm or more, preferably 1010Ω・
A transparent resin having a resistance of Cm or more, more preferably 10'3 Ω·cm or more is used. 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 resins, urethane resins, urea resins, polyester resins, alkyd resins, melamine resins, photocurable cinnamic acid resins, etc., or copolymer or condensation resins thereof, and other photo- or thermosetting resins used in electrophotographic materials. All of them are used. If necessary, the protective layer may contain less than 50% by weight of a thermoplastic resin for the purpose of improving processability and physical properties (preventing cracks, imparting flexibility, etc.). Examples of such thermoplastic resins include polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, Evokin resin, polycarbonate resin or copolymer resins thereof, polymeric organic semiconductors such as poly-N-vinylcarbazole, and others. All of the thermoplastic resins available for electrophotographic materials are utilized.

The carrier generation layer can be provided by the following method.

(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 obtained 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 method of dissolving or dispersing the gear transport substance 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, the amount of carrier transport substance added is preferably within the range of 1 to 100 parts by weight per 100 parts by weight of pine mites. Alternatively, there is a method in which a solution containing a carrier transport substance is applied onto the carrier generation layer, and 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 transporting substance to the carrier generation layer as described above, but it is also possible to carry out the above three methods at the same time.

As the solvent or dispersion medium used for forming the layer, n
-butylamine, diethylamine, ethylenediamine,
Isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylborumamide, acetone, methyl ethyl ketone, cyclohexanone,
Hensen, toluene, xylene, chloroborum, 1,2
-Dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethylsulfoxy F, and the like.

The photosensitive layer, blocking layer (subbing layer), protective layer, etc. can be formed by, for example, blade coating, dip coating, spray coating, etc.
It can be provided by roll coating, spiral coating, etc.

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, FIG. 2 shows an example of a recording apparatus using the photoreceptor of the present invention. FIG. 3 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 is a pre-transfer exposure lamp provided as necessary to facilitate the transfer of the toner image formed on the image carrier 23 onto the recording medium P; 21 is a transfer device; 19 is a separation corona discharger; A fixing device 12 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 surface of the image carrier 23 in the initial state, which has been neutralized by the static eliminator 13 and cleaned by the cleaning device 14 and has a potential of 0, is uniformly charged by the charger 22. Image exposure 24 is projected onto the charged surface to perform image exposure such that the potential of the electrostatic image portion becomes approximately O, and the obtained electrostatic image is developed by a developer 15 (toner T).

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

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

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

First, photoreceptors 1 to 33 of Examples and photoreceptors 1 to 21 of Comparative Examples were manufactured in the following manner. The manufacturing procedure for each photoreceptor is common as follows.

An aluminum cylinder with a mirror-finished surface, 80 mm in diameter, 355 mm in length, and 1 mm in wall thickness, was immersed in the blocking layer solution shown in Figures 6 to 8, and pulled up at a speed of 300 mm/min (coating speed). Then I applied the dip. After coating, it was dried at 40°C for 130 minutes to form a blocking layer with a thickness of 0.5 μm. The blocking layer solution used here was 0.6 μm.
The filter was used.

Next, 40 g of each phthalocyanine shown in FIGS. 6 to 8 as a carrier generating substance (CGM) was added to 40 g of silicone resin RK R-5240J (manufactured by Shin-Etsu Chemical Co., Ltd.).
2.000m of methyl ethyl ketone solution 7!
In addition, the mixture was dispersed for 4 hours using a sand grinder to prepare a carrier generation layer coating solution. The cylinder having the above-mentioned blocking layer was immersed in this solution, and 720 mm
Pull up and apply dip at a coating speed of /min.
A carrier generation layer (CGL) with a film thickness of 0.5 μm was obtained.

Furthermore, carrier transport materials (CT
M) 200g and polycarbonate resin “Kneepilon Z-
200J (Mitsubishi Gas Chemical) 400g was dissolved in 1°2-dichloroethane 2000+++j2, and the cylinder coated up to the carrier generation layer was immersed in the resulting solution and pulled up at a pulling speed (coating speed) of 90 mm/min. Dip coating was performed and dried at 85° C. for 1 hour to form a carrier transport layer (CTL) having a film thickness of 20 μm.

Photoreceptors 1 to 15 according to the present invention and photoreceptors 1 to 1 of comparative examples
21, a total of 36 types [U-Bix 1550
J (manufactured by Konica) (equipped with a semiconductor laser light source) was installed on a modified machine, the grid voltage was adjusted so that VH was -700 ± 10 (V), and the potential of the exposed surface when irradiated with 0.7 mW was , reversal development was performed at a developing bias of -600 [V], and black spots on the white background of the copied image were evaluated (
y, 5000 y, 9000 are the potentials after 5000 copies, respectively).

The evaluation of black spots was performed using an image analysis device "Omnicon 30".
The particle size and number of black spots were measured using "Type 00" (manufactured by Shimadzu Corporation), and the number of black spots with a diameter of 0.05 mm or more was determined based on the number of black spots per cm2.

The criteria for black spot evaluation are as shown in the table below.

Note that if the result of black spot determination is ◎ or ○, it is practical, but if it is △, it may not be suitable for practical use, and if it is ×, it is not suitable for practical use.

In addition, in order to examine the solvent resistance of the blocking layer, after coating and drying the blocking layer, it was immersed in methyl ethyl ketone, which is a solvent for the carrier generation layer, for 30 seconds, and then observed using an electron microscope (SEM). A case where the blocking layer remained homogeneous on the immersion surface was shown as ◎, and a case where the blocking layer was non-uniform, dissolved or peeled off was shown as △ or ×.

The evaluation results of Examples and Comparative Examples are shown in FIGS. 6 and 7.

According to the results, by providing a blocking layer according to the present invention, electrophotographic properties such as charging, sensitivity, and repeated potential stability are maintained well, and there is no black spot (i.e., the blocking layer is homogeneous). properties) It is possible to obtain an excellent photoreceptor.

On the other hand, if a blocking layer is not provided as in Comparative Examples 1 to 7, black spots will occur frequently, and if resins such as Comparative Examples 8 to 14 are used, the solvent resistance of the blocking layer will be insufficient. cannot prevent black spots.

Further, in the case of Comparative Examples 15 to 21, the homogeneity of the blocking layer was good and there were no problems with black spots, but the sensitivity as a photoreceptor performance in particular deteriorated.

[Brief explanation of the drawing]

1 to 7 show examples of the present invention. FIGS. 1, 4, and 5 are cross-sectional views of a portion of each photoreceptor used in the present invention, and FIG. A schematic diagram of the image forming apparatus; FIG. 3 is a flowchart showing the process of image formation; FIG. 6;
FIG. 7 is a table showing a comparison of the characteristics of each photoreceptor. FIG. 8 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-- --------Blossoking layer 8------This is a photosensitive layer. Agent: Patent Attorney Hiroshi AisakaFigure 1Figure 3

Claims (1)

[Claims] 1. In a photoreceptor in which a blocking layer and a photosensitive layer containing an organic photoconductive substance are provided on a conductive support, a substituted or unsubstituted ethylene hydrocarbon and acrylic acid and/or methacrylic acid are combined. A photoreceptor characterized in that the blocking layer is formed of a copolymer as a copolymer component.