JPH02212853A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body inhibiting the occurrence of image defects such as black spots and having superior sensitivity, printing resistance, potential stability and residual potential characteristics by forming an underlayer with a copolymer of ethylene with unsatd. carboxylic ester and other monomer. CONSTITUTION:When an underlayer 7, a carrier generating layer 6 and a carrier transferring layer 4 are successively laminated on an electrically conductive substrate 1 to obtain a photosensitive body, the underlayer 7 is formed with a copolymer of ethylene with unsatd. carboxylic ester and other monomer. The copolymer has blocking function to prevent ununiform hole injection from the substrate 1 liable to occur in the case of an org. photoconductive substance having high hole mobility and also has satisfactory adhesive property to the substrate 1. A barrier to local carrier injection from the substrate 1 side can be formed by the underlayer 7 and the vanishment or reduction of surface charges due to local carrier injection can be prevented. A superior photosensitive body inhibiting the occurrence of black spots while maintaining satisfactory electrophotographic characteristics such as electrostatic chargeability, sensitivity and repetitive potential stability is obtd.

Description

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

[Background of the invention]

In the Carlson electrophotographic copying method, after the surface of the 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 printed on paper, etc. Transcribe it into a theorem. At the same time, the photoreceptor is subjected to removal of accumulated toner, neutralization, 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 and 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, inorganic photoreceptors having a photoreceptor layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a main component have been widely used as electrophotographic photoreceptors.

On the other hand, the use of various organic photoconductive substances as materials for photoreceptor layers of electrophotographic photoreceptors has been actively researched and developed 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 different substances to the carrier generation function and the carrier transport function in the photosensitive layer.

In such functionally separated electrophotographic photoreceptors, substances that exhibit each function can be selected from a wide range of materials, so it is relatively easy to produce an electrophotographic photoreceptor with arbitrary characteristics. is possible.

Therefore, it is expected that an organic photoreceptor with high sensitivity and durability will be obtained.

The first rM indicates a functionally separated electrophotographic photoreceptor using such an organic photoconductive substance.

This electrophotographic photoreceptor has a subbing layer 7 on a conductive support l.
, a carrier generation layer 6 and a carrier transport layer 4 are sequentially laminated, and is used for negative charging. That is, the photosensitive layer 8 is composed of the carrier generation layer 6 and the gear transport layer 4.

In an electrophotographic photoreceptor having such a layer structure,
*Since the mobility of holes is greater than that of electrons in the case of chargeability, a hole transporting photoconductive material with good properties can be used, which is advantageous in terms of photosensitivity, etc.

However, such photoreceptors, especially those using organic photoconductive materials, are prone to uneven carrier (hole) injection from the conductive support or lower layer side when negatively charged, as shown in Figure 2. As a result, the surface charge disappears or decreases when viewed microscopically. This results in image defects in the form of black spots (black spots), particularly in the reversal development method, which significantly reduces the quality of the image.

This problem of black spots is a peculiar phenomenon in photoreceptors using organic photoconductive materials with high hole mobility, and the cause thereof is thought to be non-uniform carrier injection as described above.

Therefore, it has been proposed to provide a subbing layer between the conductive support 1 and the photosensitive layer to block carrier injection. Materials constituting the undercoat layer 7 include polyester,
Resins such as polyvinyl butyral, polyvinyl formal, polyvinyl acetate, polyvinyl chloride, polyvinylphenol, and cellulose are known.

However, the above-mentioned known undercoat layer does not have a sufficient effect of suppressing black spots. Moreover, it has not been achieved to improve both the blocking property and the sensitivity as a photoreceptor. In other words, among the conventionally used resins, those that have effective blocking properties and are thought to have the effect of suppressing black spots have poor sensitivity, and conversely, when trying to improve sensitivity, the blocking properties are insufficient and black spots suddenly appear. cannot be suppressed sufficiently.

Therefore, Japanese Patent Laid-Open No. 60/218658 proposes a technique of adding an electron donating substance to an ethylene copolymer resin.

In this technique, a carrier trap is formed by adding an electron donating material into the underlayer, which prevents carrier injection from the conductive support to some extent. However, the above technique has the disadvantage that the residual potential increases during repeated use due to carrier traps in the undercoat layer, and the sensitivity is insufficient.

Furthermore, when a normal ethylene copolymer is used for the undercoat layer,
There may be problems with the coating properties of the carrier generation layer (poor wetting of the carrier generation layer immediately after coating the undercoat layer, uneven coating of the undercoat layer tends to appear on the carrier generation layer), or problems may arise between the undercoat layer and the carrier generation layer. Adhesion is often poor.

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 (Ga41.
-As) type light emitting elements have an oscillation wavelength of approximately 75 on- or more.

Although such a technical system using a laser beam or the like is expected to be applied to printers, the current situation is that a photoreceptor having high sensitivity to long wavelength light has not yet been developed.

An object of the present invention is to provide a photoreceptor that can suppress image defects such as black spots and has sufficient sensitivity to relatively long wavelength light from semiconductor lasers and the like.

Another object of the present invention is to provide a photoreceptor with excellent printing durability, potential stability, and residual potential characteristics.

An object of the present invention is to sequentially laminate a subbing layer, a carrier generation layer, and a carrier transport layer on a conductive support; Our goal is to provide an excellent photoreceptor.

[Structure of the invention and its operation]

That is, the present invention provides a photoreceptor in which at least an undercoat layer and a photosensitive layer are provided on a conductive support, in which the undercoat layer contains ethylene, an unsaturated carboxylic acid ester, and other monomers. The undercoat layer is formed of a copolymer.

According to the present invention, it is extremely important that the subbing layer provided on the support is formed of a copolymer having the above composition.

That is, as mentioned above, this copolymer effectively prevents non-uniform hole injection from the support, which tends to occur when an organic photoconductive substance with high hole mobility is used in the photosensitive layer. It has a blocking function, has good foliage properties with the base, and can be formed uniformly, so it can fully exhibit its blocking Ia ability. In particular, no precipitates are generated when forming the undercoat layer,
Further, the resin of the undercoat layer does not dissolve out during the coating formation of the upper layer. Therefore, it is considered that the presence of this undercoat layer can provide a barrier to local carrier injection from the support side, and can 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.

In this undercoat layer, if the above-mentioned copolymer component consists only of ethylene hydrocarbon (in this case, it becomes a homopolymer), the solubility and adhesion to the substrate will not be sufficient. In the undercoating layer of the body, examples of unsaturated carboxylic acid esters copolymerized with ethylene include acrylic esters and methacrylic esters, and other monomers copolymerized with these include acrylic acid and methacrylic acid. , maleic acid, maleic anhydride, vinyl acetate, vinyl chloride, vinyl fluoride, propylene, and the like.

In the copolymer, the ethylene content is preferably 40 vt% or more, and the unsaturated carboxylic acid ester content is preferably 1 to 50 vt%. Furthermore, the proportion of the copolymerized components other than ethylene is 1 to 501% of the total (100vt%).
It is desirable to set it as 10-40! It is more desirable to set it to t%. If the proportion of the copolymer component is small, the effects of containing the copolymer (film attachment, reduction of image defects, CGX, C carrier generation layer, coating properties) tend to decrease, and if the proportion of the copolymer component is high, the blocking function is likely to decrease. decrease becomes greater.

As a guideline for the molecular weight of this copolymer, MFR (JiS
- Melt 70-rate according to K 6730-1981)
is preferably 1 to 500g, /login.

In the photoreceptor of the present invention, specific examples of the copolymer according to the present invention forming the undercoat layer include the following resins.

A Ethylene-unsaturated carboxylic acid ester-unsaturated carboxylic acid copolymer Pondia TX-8030 (Sumika Sheep 4-r-
y)HX-8290(//)-802
0 (// ) A X -8060 (// ) -8390 (
tt) B Ethylenically unsaturated carboxylic acid ester-vinyl acetate copolymer Pondfast-A (Sumitomo Chemical) 13 (tt
) E (〃 ) G (〃 ) The undercoat layer used in the present invention has a thin film thickness of 1 μm or less, so that it can sufficiently exhibit blocking performance while suppressing residual potential, etc. This is desirable in terms of maintaining good photoreceptor performance.

The photoreceptor of the present invention has, for example, the structure shown in the first factor.

In this photoreceptor, a conductive support (substrate)! above,
A carrier generation layer 6 is provided via the above-mentioned undercoat layer 7, and a carrier transport 114 is provided on this carrier generation layer 6. 8 indicates a photosensitive layer. Therefore, since the subbing layer 7 is provided between the carrier generation layer 6 and the support 1, it effectively prevents uneven hole injection from the support side as shown in FIG. In some cases, electrons, which are photocarriers, can be efficiently transported to the support side.

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 also 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, the fifth
As shown in the figure, the layer structure may be such that the carrier generation layer 6 and the carrier transport layer 4 are turned 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 in order to improve printing durability, for example, a synthetic resin film may be coated.

In the photoreceptor of the present invention, organic pigments as shown in the following representative examples are used as carrier generating substances.

(1) Azo pigments such as monoazo pigments, bisazo pigments, triazo pigments, and metal complex azo pigments (2) Perylene pigments such as perylene acid anhydride and perylene acid imide (3) Anthraquinone derivatives, anthanthrone derivatives, dibenzpyrene quinone derivatives, vilantrone derivatives,
Polycyclic quinone pigments such as violanthrone derivatives and inviolanthrone derivatives (4) Indigoid pigments such as indigo derivatives and thioindigo derivatives (5) 7-lycyanine pigments such as metal 7-lyronanine and metal-free phthalocyanine Among these, phthalocyanine-based pigments The pigment has high sensitivity in a high wavelength range and is suitable for the photoconductor for semiconductor laser according to the present invention.

Examples of metal phthalocyanines include those containing copper in the center (Japanese Patent Publication No. 1667, JP-A No. 55-60958, JP-A No. 57-20741, etc.), those containing aluminum, titanium, vanadium, indium, etc. (Unexamined Japanese Patent Publications No. 53-89433, No. 57-148745, No. 6
3-218768, patent application No. 62-173640, etc.)
Oxytitanium phthalocyanine (Y-type, β-type, A-type) is preferable since it increases sensitivity.

In addition, examples of metal-free phthalocyanine include χ-type metal phthalocyanine (Japanese Patent Publication No. 49-4338), τ-type metal-free phthalocyanine (Japanese Patent Application Laid-Open No. 58-182639), and σ, β.
, type phthalocyanine is mentioned, and τ type is preferable due to the addition of sensitivity and potential stability.

Preferably used carrier-generating substances include azo pigments introduced in Japanese Patent Application Laid-Open No. 194035/1982, Japanese Patent Application No. 336384/1982, etc., and bisazo compounds represented by the following general formula CF) are particularly preferred. .

General formula (F) In the formula, Q , , Q 1 represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cyano group, or a trifluoromethyl group.

Halogen atoms include chlorine atom, bromine atom, iodine atom,
Alkyl groups include methyl group, ethyl group, butyl group,
The alkoxy group is methoxy group.

Examples include ethoxy group and butoxy group. Particularly preferred are hydrogen atoms and halogen atoms.

Cp represents a coupler residue, and has the following structural formulas (1) to (11
) are preferred.

In the formula, 2 represents an atomic group necessary to form a polycyclic aromatic ring or a heterocycle by condensation with a benzene ring.

R,,R! represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, a heterocyclic group, or a substituent thereof. Further, it may form a ring together with a nitrogen atom or a carbon atom.

R8 is 0. Represents S, -NH.

R4 and R* represent a hydrogen atom, an alkyl group, an alkoxy group, a nitro group, a cyano group, a halogen atom, or an acetyl group.

A represents a divalent group of a carbocyclic aromatic ring or a heterocyclic aromatic ring.

R represents an alkyl group, an aralkyl group, an aryl group, a heterocyclic group, or a substituted product thereof.

R7 represents a hydrogen atom, an alkyl group, a dialkylamino group, a diarylamino group, a dialkylamino group, a carbamoyl group, a carboxy group, or an ester group thereof.

R1 represents an aromatic ring group or a substituted product thereof.

Among these coupler residues, (1), (3), (9)
(lO) is preferred, especially the following structural formula (ia).

(1-b) is preferred.

General formula [Q,] (1-a) (1-b) In the formula, Y+ and Y* represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a nitro group, a cyano group, and a trifluoromethyl group.

Further, as pigments other than those mentioned above, which are preferably used, there are polycyclic quinone pigments described in JP-A-55-126254, an example of which is represented by the following general formula (Q).

[Q! ] and [Q, ].

General Formula [Q1] General Formula [Q3] Here, R', R, R3, and R' represent a halogen atom, and X represents a halogen atom and a polygroup of NOx, CN, C0C)I>.

n is an integer from O to 4.

In the carrier generation layer, the content ratio of the carrier generation substance to the binder substance is preferably 5/l-1/1.0, more preferably 3/l-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 the carrier-generating substance is too small, photosensitivity and the like will decrease.

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 10μ■ or more.

The thickness of the entire photosensitive layer is preferably within the range of lO to 40 .mu.l, and more preferably within the range of 15 to 30 .mu.l. 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 is formed by dispersing a granular carrier-generating substance, the carrier-generating substance is a powder having an average particle size of 2 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less. is preferable.

Further, in the carrier transport layer, the carrier transport substance preferably has excellent compatibility with the binder substance.

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.Also, due to the excellent compatibility, carrier generation The layer is uniform and stable, resulting in better sensitivity and charging characteristics, and a photoreceptor that can form clearer images with higher 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 of the other carrier-generating substances E in combination. Examples of carrier-generating substances that can be used in combination include anthraquinone pigments, perylene pigments, methine succinate 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, triazole derivatives, imidazole derivatives, imidazolo:/ 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, sti4 to 7sal1 , ;t
: May be one or more selected from IJ-N-vinylcarbasol, holy l-vinylpyrene, poly-9-vinylanthracene, etc.

Specific examples of such carrier transport substances are disclosed in Japanese Patent Application Laid-open No. 6
No. 3-50851. The general formula is listed below.

As a carrier transport substance, the following general formula [■] or [■]
styryl compounds can be used.

General formula [■]: (However, in this general formula, R": 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.

Ar', Ar': Represents a substituted or unsubstituted aryl group, and examples of the substituent include an alkyl group, an alkoxy group, a substituted amine group, a hydroxyl group, a halogen atom, and an aryl group.

R's R14 represents a substituted or unsubstituted aryl group or a hydrogen atom, and examples of substituents include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, and an aryl group. ) General formula [■]; [x], (X a) (X b:l or Bt) (7
)t: Drazine compounds can also be used.

General formula [■]: (However, in this general formula, R = substituted or unsubstituted aryl group, R dihydrogen atom, halogen atom, substituted or unsubstituted alkyl group,
Alkoxy group, amino group, substituted amino group, hydroxyl group, R11: represents a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group. ) Also, the following general formula [■] is used as a carrier transport substance.

(However, in this general formula, R1 and RII: each represents a hydrogen atom or a halogen atom, RfO and R'': each represents a substituted or unsubstituted aryl group, and Ar': represents a substituted or unsubstituted arylene group.) General formula [ Xa: (However, in this general formula, R2! represents a substituted or unsubstituted aryl group, a substituted or unsubstituted carbazolyl group, or an R-substituted or unsubstituted heterocyclic group, Rj3.81 and Rls: hydrogen Represents an atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.) General formula (Xa): ■ (However, in this general formula, R■: methyl group, ethyl group, 2 -Hydroxyethyl group or 2-chloroethyl group, R":)9-l group, ethyl group, benzyl group or phenyl group, Rta, methyl group, ethyl group, benzyl group or phenyl group. ) (However, in this general formula, R■: Substituted or unsubstituted 7-tyl group; R1@ co-substituted or unsubstituted alkyl group, aralkyl group, or aryl group; R: hydrogen atom, aralkyl group, or alkoxy group ; R engineering 2 and Rls, substituted or unsubstituted alkyl group,
Indicates mutually the same or different groups consisting of an aralkyl group or an aryl group. ) General formula [■]: (However, in this general formula, R34: substituted or unsubstituted aryl group or substituted or unsubstituted heterocyclic group, R31, hydrogen atom, substituted or unsubstituted aralkyl group, or substituted or unsubstituted aralkyl group) Substituted aryl group, Q: hydrogen atom, halogen atom, alkyl group, substituted amino group, alkoxy group, or cyano group, s: represents an integer of 0 or l.) In addition, as a carrier transport substance, the following general formula (n ) pyrazoline compounds can also be used.

General formula (n): RlI: substituted or unsubstituted aryl group or heterocyclic group, R1 and R'. : Hydrogen atom, alkyl group having 1 to 4 carbon atoms, or substituted or unsubstituted aryl group or aralkyl group (However, Ro and R'' are not both hydrogen atoms, and when Q is 0, (Rsa is not a hydrogen atom.) Furthermore, an amine derivative of the following general formula (xm) can also be used as a carrier transport material.

General formula (Xlff): (However, in this general formula, a: 0 or 1 BAG and R37 = substituted or unsubstituted aryl group,
(However, in this general formula, A r', A r' 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.7 Substituents include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group, an aryl group, and an amino group. group, nitro group, piperidino group, morpholino group, naphthyl group, anthryl group, and substituted amino group.However, as a substituent for the substituted amino group, acyl group, alkyl group, aryl group, and aralkyl group are used.) Furthermore, the following Compounds of general formula (xiv) can also be used as gear transport materials.

General formula [' (or represents an unsubstituted aryl group, or a substituted or unsubstituted aralkyl group) Furthermore, a compound of the following general formula (xB) can also be used as a carrier transport substance.

General formula (xv): [However, in this general formula, Rls, H4g, RIF and R
41 is a hydrogen atom, a substituted or unsubstituted alkyl group, cycloalkyl group, alkenyl group, aryl group, benzyl group or aralkyl group, R49 and Rsa are,
1 hydrogen atom, substituted or unsubstituted carbon atom, respectively
~40 alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl or aralkyl groups (
However, R1 and R1 may jointly form a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms. ) RSI, SI, R13 and R14, hydrogen atom, halogen atom, hydroxyl group, substituted or unsubstituted alkyl group, cycloalkyl group, alkenyl group,
Aryl group, aralkyl group, alkoxy group, amino group,
It is an alkylamino group or an arylamine 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 charging 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, organic phosphorus compounds, and the like.

These specific compounds are described in JP-A-63-141.
No. 53, No. 63-18355, No. 63-44662, No. 63-50848, No. 63-50849, No. 6
3.58455, 63.71856, 63-7
It is described in No. 1857 and No. 63/146046.

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 one 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. It is something. Further, at least one electron-accepting substance may 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, dibromomaleic anhydride, phthalic anhydride, te]-rachlorphthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride. , mellitic anhydride, tetracyanoethylene, tetracyamiquinodimethane, O-dinitrobenzene, rs-'; nitrobenzene, 1,3.5-trinitrobenzene, varanitrobenzonitrile, vicryl chloride, quinone chlorimide, chloranil, Brumanil, 2-methylnaphthoquinone, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-7J leolenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene [dicyanomethylenemalonodinitrile], picrin 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 types of compounds with high electron affinity Or two or more kinds can be mentioned.

Among these, fluorenone series, quinone series, (J,
Benzene derivatives having electron-withdrawing substituents such as CN, NO, etc. are particularly preferred.

Furthermore, silicone oil or 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, stilbene 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 for 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-acetic acid Insulating resins such as vinyl copolymer resins, styrene-butadiene copolymer resins, vinylidene chloride-acrylonitrile copolymer resins, and even polymers such as N-vinyl rubazole! II semiconductor,
Examples include modified silicone resins.

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

If necessary, the binder for the protective layer may be
Volume resistance 10'Ω・Cl11 or more, preferably 101G
Ω・cm or more, preferably 10′! A transparent resin having a resistance of Ω·Cl11 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 resin, urethane resin, urea resin, polyester resin, alkyd resin, Examples include melamine resins, photocurable cinnamic acid resins, and copolymerized or condensed resins thereof, and all other photocurable or thermosetting resins used in electrophotographic materials can be used. If necessary, the protective layer may contain less than 5 Qwt% of a thermoplastic resin for the purpose of improving processability and physical properties (preventing cracks, imparting flexibility, etc.). Such thermoplastic resins include, for example, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polycarbonate resin, or copolymerized resins thereof, polymeric organic semiconductors such as poly-N-vinylcarbazole, etc. , and all other thermoplastic resins used in electrophotographic materials can be used.

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 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 coating and drying the above-mentioned carrier transport substance alone or by dissolving and dispersing it together with the above-mentioned binder resin.

In case 2, when a carrier transporting substance is contained in the carrier generation layer, the carrier transporting substance is dissolved or dispersed in advance in the solution of (a) or the dispersion of (b) above, that is, the method of dissolving or dispersing the carrier transporting substance 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 should be 10% of the binder.
It is preferably within the range of 1 to 100 parts by weight relative to 0 parts by weight. Alternatively, there is a method in which a solution containing a carrier transport substance is applied onto the carrier generation layer, the carrier generation layer is partially or partially dissolved, and the carrier transport substance is diffused 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 two 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-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1.2-
Dichloroethane, dichloromethane, tetrahydrofuran, dioxane q methanol, ethanol, inglobanol, ethyl acetate, butyl acetate, dimethyl sulfoxide and the like can be mentioned.

The photosensitive layer, undercoat 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 may be a metal plate, a metal drum, or a conductive thin layer made of a conductive polymer, a conductive compound such as indium oxide, or a metal such as aluminum, palladium, or gold, by coating, vapor deposition, lamination, etc. Depending on the means, those provided on a substrate such as paper or plastic film may be used.

Next, FIG. 2 shows an example of a recording apparatus using the photoreceptor of the present invention. FIG. 3 is a flowchart of reversal development in electrophotography.

In the apparatus shown in FIG. 2, 23 is a drum-shaped photoreceptor which has the above-mentioned organic photoconductive photosensitive layer 8 and subbing layer 7 and rotates in the direction of the arrow; 24 is an image exposure device, and 15 is a developing device. 20
The toner image formed on the photoconductor 23 is transferred to the recording medium P.
21 is a transfer device, 19 is a separating corona discharge device, and 12 is a fixing device for fixing the toner image transferred to the recording medium P. 13 is a static eliminator consisting of one or a combination of a static elimination lamp and a corona discharger for static elimination; 14 is a photoreceptor 2;
This cleaning device has a cleaning blade and a fur brush for removing residual toner on the surface after transferring the image No. 3.

When image exposure is performed using a semiconductor laser, in a recording device using a drum-shaped photoreceptor 23 like the recording device shown in FIG.
Image exposure 24 is preferably performed by a laser beam scanner. Further, in a recording apparatus in which the photoreceptor is in a flat state such as a belt, the image exposure can be made into 7-lash exposure.

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

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 photoconductor 23 in the initial state, which has been cleaned in step 4 and has a potential of 0, 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 so that the potential becomes approximately 0, and the obtained electrostatic image is developed by a developing device 15 (toner T).

This imaging 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.

〔Example〕

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 1 to 6 of Examples and photoreceptors (1,) to (8) of Comparative Examples were manufactured in the following manner. The manufacturing procedure for each photoreceptor is common as follows.

First, the following resins were added to toluene (concentrations are listed in Table 1) and completely dissolved while heating to 50° C. to prepare a coating solution for an undercoat layer.

・Bondine p, x 8060 (Sumitomo Chemical II)
・Bond First A (Sumitomo Chemical) ・Resin for comparison (
Table 2) This liquid has a diameter of 80 mm, a length of 355 mm, and a wall thickness of 1 ms.
An aluminum cylinder with a mirror-finished surface was immersed in Table 1 and Table 2, and the pulling speed (coating speed) was 300.
■ Dave coating was carried out at a speed of m/mfn. After coating, it was dried at 40° C. for 30 minutes to form a subbing layer with a thickness of 0.5 μm. The solution for the undercoat layer here is 0.6μ
The material filtered through the filter (2) was used.

Next, 40 g of each of the 7-tricyanine shown in Tables 1 and 2 as a carrier generating substance (CGM) was added to a methyl ethyl ketone solution in which 2 DO g of silicone resin rK R-5240J (manufactured by Shin-Etsu Chemical Co., Ltd., solid content 20%) was dissolved. 2.00
In addition to 0mR, use a sand grinder 41)? A coating solution for a carrier generation layer was prepared.

Regarding the bisazo pigment, 15 g was processed into 1000 sQ of a methyl ethyl ketone solution in which 5 g of butyral resin [S-LEC BH-3J (manufactured by Tsukisui Kagaku Co., Ltd.) was dissolved, and dispersed in a ball mill for 12 hours to prepare a coating solution vR in the same manner.

The cylinder having the above-mentioned subbing layer was immersed in this liquid, and 7
Dip coating was performed at a coating speed of 20 m5/win, and a carrier generation layer (CGL) with a thickness of 0.5 μm was applied.
) was obtained.

Furthermore, carrier transport substances (CT
M) 200g and polycarbonate resin “Nipiro 7Z”
-200J (Mitsubishi Gas Chemical) 400g was dissolved in 2000mg of 1,2-dichloroethane, and in the resulting solution,
The cylinder coated up to the carrier generation layer is immersed, and 9
Dip coating was performed by pulling at a pulling speed (coating speed) of 0 mm/aiin, drying at 85°C for 1 hour,
A carrier transport layer (CTL) having a film thickness of 0 μm was formed.

Photoreceptors 1 to 6 according to the present invention and photoreceptors (1) to Comparative Examples
(8) for each of the 14 types in total r U -B 1x15
50J (manufactured by Konica) (equipped with a semiconductor laser light source) was installed in a modified machine, and the grid voltage was adjusted to 1700 ± 10 (V), and the potential of the exposed surface when irradiated with 0.711 IW was V, reversal development was performed at a developing bias of -600 (V), and black spots on the white background of the copied image were evaluated (V, S@@a V L'0@1.i Sole 5000 each After copying The black spots were evaluated by measuring the particle size and number of black spots using an image analysis device "Omnicon 300" (manufactured by Shimadzu Corporation).
Judgment was made based on the number of black spots of m or more per lam". The criteria for black spot evaluation are as shown in the table below.

In addition, if the result of black spot determination is ◎ or O, it will be practical, but
△ may not be suitable for practical use, and × may not be suitable for practical use.

In addition, in order to check the solvent resistance of the undercoat layer, after coating and drying the undercoat layer, it was immersed in methyl ethyl ketone, a solvent for the carrier generation layer, for 30 seconds, and then subjected to electron microscopy (SEM).
) observations were made. A case where the subbing layer remained homogeneous on the immersion surface was indicated by ◎, and a case where it was heterogeneous or had peeling due to the solvent was indicated by Δ or X.

Regarding the coatability (wettability) of CGL on the undercoat layer,
As mentioned above, when applying CGL daylag, it repels,
◎ indicates that the coating can be applied uniformly without dripping and there is no unevenness; ◎ indicates that the coating can be applied uniformly; △ indicates that the coating film has unevenness; and ◎ indicates that the coating cannot be applied uniformly.

The adhesion between the undercoat layer and the photosensitive layer was evaluated by a substrate test. In other words, the distance between adjacent gaps is l
Using an aw cutter guide, make 11 parallel scratches vertically and horizontally on the conductive support with a cutter, making 100 squares (
form the basal orders). After pasting cellophane tape with a diameter of 24a+m on top of it, peel it off from one end. The number of squares that were peeled off at that time was counted, and the number of squares remaining out of 100 was first expressed as the number of squares.

As a guideline for adhesion, if it is too/100, it is considered good adhesion, and if it is O/100, it is considered poor.

Tables 1 and 2 show the evaluation results of Examples and Comparative Examples.

According to the results, by providing an undercoat layer based on the present invention, electrophotographic properties such as charging, sensitivity, and repeated potential stability are maintained well, and there is no black spot (i.e., no black spots).
(Homogeneity of subbing layer) An excellent photoreceptor can be obtained.

On the other hand, if the undercoat layer is not provided as in Comparative Examples (1) and (2), black spots will occur frequently, and when the resins as in Comparative Examples (3) and (4) are used, the undercoat layer will not be formed. Black spots cannot be prevented because of insufficient solvent resistance. Also, comparative examples (5) to (8)
In this case, the homogeneity of the undercoat layer is good and there are few problems with black spots, but the sensitivity and adhesion are poor.

[Brief explanation of the drawing]

1 to 6 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. FIG. 3 is a schematic diagram of the image forming apparatus. FIG. 3 is a flowchart showing the process of image formation. FIG. 6 is a sectional view of a portion of a conventional photoreceptor. In addition, in the reference numerals shown in the drawings, l... Conductive substrate 4... Carrier transport layer 6... Carrier generation layer 7... Undercoat layer 8... Photosensitive layer.

Claims (1)

[Claims] In a photoreceptor in which at least an undercoat layer and a photosensitive layer are provided on a conductive support, the undercoat layer is formed of a copolymer containing ethylene, an unsaturated carboxylic acid ester, and other monomers. A photoreceptor characterized by: