JPH04195058A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive body restrained from image defects, such as black spots, and sufficient in sensitivity to comparatively long wavelength light, such as semiconductor laser beams, by forming an undercoat layer made of an epoxy type radiation curing resin on a conductive substrate. CONSTITUTION:The photosensitive body is formed by laminating at least the undercoat layer (UCL) 7 and a photosensitive layer (PCL) 8 on the conductive substrate 1, and the undercoat layer 7 is made of the epoxy type radiation-curing resin having at least one of radiation-sensitive unsaturated acrylic double bond, allyl type double bond, and maleic type double bond, thus permitting a barrier against local injection of carriers from the side of substrate 1 to be formed, and the loss or decrease of surface charge due to said local carrier injection to be prevented.

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 transferred to paper or the like. Transfer and fix. At the same time, the photoreceptor is subjected to removal of adhering 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 not only to 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 the second purpose, in the photosensitive layer, the carrier generation function and the carrier transport function are assigned to different substances, so that the so-called functionally separated layers with high sensitivity and durability are laminated. Attempts have been made to develop organic photoreceptors.

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.

FIGS. 2 and 4 show a function-separated type laminated electrophotographic photoreceptor using such an organic photoconductive substance.

FIG. 3 shows a functionally separated single-layer electrophotographic photoreceptor.

The electrophotographic photoreceptor shown in FIG. 2 is constructed by sequentially laminating an undercoating layer (UCL) 7, a carrier generation layer (CGL) 6, and a carrier transporting layer (CTL) 4 on a conductive support 1. It is used for negative charging. That is,
Photosensitive layer (P CL) 81; i CG L 6 to CT
It is composed of L4.

In an electrophotographic photoreceptor having such a layer structure,
In the case of negative chargeability, the mobility of poles is greater than that of electrons, so a hole-transporting photoconductive material with good properties can be used, which is advantageous in terms of photosensitivity and the like.

Next, FIG. 4 shows a photoreceptor for positive charging. In such laminated photoreceptors, especially photoreceptors using organic photoconductive materials, non-uniform carrier (pole) injection from the conductive support or lower layer side tends to occur when negatively charged, resulting in slight surface charge. It visually disappears or decreases. 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.

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

Therefore, it has been proposed to provide a UCL between the conductive support 1 and the PCL to block carrier injection.

Conventionally, materials constituting UCL7 include polyester, polyurethane, polyamide, Epoquine resin,
Known materials include polycarbonate, vinyl polymer, such as polyvinylpyridine acrylic resin, cellulose, polyketal, and condensation polymer, such as phenol resin and melamine resin. However, the above-mentioned known undercoat layer does not have a sufficient effect of suppressing black spots. Moreover, it has not yet been demonstrated that both the blocking property and the sensitivity as a photoreceptor can be improved. In other words, among the resins conventionally used, 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 appear. cannot be sufficiently suppressed.

Additionally, problems arise during the multilayer coating process. If the solubility of the polymers in the upper and lower layers is similar, part of the lower layer will dissolve when the upper layer is applied, and the interface between the upper and lower layers will be disturbed and coating will not be possible, or if coating is done by dipping, the upper layer coating tank will be This not only shortens the life of the expensive upper layer coating solution but also deteriorates the potential characteristics of the photoreceptor due to contamination with the constituent components of the lower layer.

These factors impose strict prescription restrictions on the polymers and solvents in the upper and lower layers.

Although there are examples of applying thermosetting resins to UCL, productivity deteriorates because a high curing temperature (at least 1.10'C or more) and a relatively long time (30 minutes or more) are required.

Moreover, the stability of the coating liquid mixed with the curing agent is essentially deteriorated.

Furthermore, the adhesion is still insufficient, and the support and UCL
At present, the adhesion between the UCL and the upper layer is poor in addition to the adhesion between the UCL and the upper 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-arsenide (Ga-AI) is widely used in semiconductor lasers.
-As) type light emitting element has an oscillation wavelength of about 750 nm or more.

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

[Purpose of the invention]

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.

Another object of the present invention is to provide a photoreceptor having good coating properties and adhesion properties, in which at least UCL%PCL is provided on a conductive support.

[Structure of the invention and its effects]

The present invention is a photoreceptor in which at least a subbing layer and a photosensitive layer are provided on a conductive support, and the UCL is formed of an epoxy/based radiation-curable resin.

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

The above resin has good adhesion to the substrate and the upper layer, and when the upper layer is coated, the resin of the subbing layer does not elute, so there is no possibility of deterioration of the performance of the photoreceptor due to contamination of the upper layer coating solution. The life of the upper layer coating solution is also extended.

As mentioned above, this polymer has a blocking function that effectively prevents uneven pole injection from the support, which tends to occur when organic photoconductive materials with high hole mobility are used in PCL. are doing.

Therefore, the presence of this undercoat layer can provide a barrier to local carrier injection from the support side.
It is thought that it is possible to 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, no rough edges, no pinholes, and a high-quality image without image defects. can play.

The epoxy polymer used in the present invention, for example, epoxy acrylate, is generally synthesized by adding acrylic acid or an acrylate having a terminal carboxyl group to an epoxy compound.

As the epoxy compound, bisphenol A diglycidyl ether type, novolac polyglycidyl ether type, evoquinated oil and fat, evoquinated polybutadiene, fatty acid-modified epoxy resin, etc. are used.

These may be used alone or in combination.

Examples of epoxy resins having acrylic double bonds include l.

Book-CH2qOCOCHCH2 Viscoat #540 2.

CH.

CH=CH2 etc.

When using the compound of the present invention, a photopolymerization initiator may be added to increase UV absorption and curing speed. Examples include benzoin ethers, benzyl ketals, α-hydroxy/acetophenonones, talolacetophenones, a-aminoacetophenones, acylphosphine oxides, a-dicarbonyls, and a-anroxime esters. etc. Examples of the radiation that can be used include ultraviolet rays, electron beams, X-rays, and gamma rays, with ultraviolet rays and electron beams being preferred.

Curing by ultraviolet irradiation has a wavelength of approximately 2000 to 4000
This is done by irradiating ultraviolet A. Furthermore, a mercury lamp with an output of about 50 to 100 W/cm is suitable for the ultraviolet ray generator. Electron beam irradiation uses an accelerating voltage of 100 to 750
It is carried out using an electron beam accelerator of KV, preferably 150 to 300 KV, so that the absorbed dose is 2 to 20 Mrad.

There is no major difference in prescription between using ultraviolet rays and using electron beams, except that when using ultraviolet rays, a photopolymerization initiator may be required.

The UCL in the present invention has a thin film thickness of 2 μm or less, and while exhibiting sufficient blocking performance,
This is desirable in terms of maintaining good photoreceptor performance such as suppression of residual potential. More preferably, it is 0.2 to 1.0 μm.

The photoreceptor of the present invention has the structure shown in FIG. 2, for example.

In this photoreceptor, on a conductive support (substrate) 1,
CGL6 is provided via the above-described UCL7, and this CGL6 is provided via the above-mentioned UCL7.
CTL4 is provided on GL5. 8 indicates PCL. Therefore, since the UCL 7 is provided between the CGL 5 and the support l, it effectively prevents the injection of non-uniform holes from the support side as shown in FIG. It is possible to transport electrons efficiently.

Note that the photoreceptor of the present invention has the above-described structure (i.e., CGL
In addition to stacking CTL on top), as shown in Figure 3, carrier generating material (CGM) and carrier transporting material (CT~1)
It may consist of a single layer of PCL8 mixed with. Alternatively, as shown in FIG. 4, the layer structure may be such that the CGL6 and CTL4 are turned upside down (for positive charging). In addition, in the photoreceptor of the present invention, a protective layer (
A protective layer (0CL) may be formed, for example, a synthetic resin film may be coated.

Next, CGM used in the photoreceptor of the present invention is shown by a general formula.

1. Polycyclic quinone pigment (1) Anthorone pigment general formula (GIN: (2) Dibenspirene quinone pigment general formula [G2]: (3) Pyranthrone pigment general formula CG3]: In the above, X: halogen atom, nitro group, cyano group, acyl group, or carboxyl group.

n=0-4 m=0-6 2.7 Zulenium Compound The azulenium compound is, for example, a metal compound described in the following publication.

(a) JP 61-1547 (b) JP 61-1548 (c) JP 61-15147 (d) JP 61-15150 (e) JP 61-15151 Specific examples of azulenium compounds include those of the following general formula. Things can be mentioned.

General formula [G4]: However, in the above general formula, 8 units, R", RI3, R14, R", R16, R17:
Represents a hydrogen atom, a halogen atom, or an organic residue. Also, R
Among the combinations of "and R12, R12 and R13, R eye and 814%, 8 mouths and R15, RIS and R eye, R" and RI7,
Any one combination may form a substituted or unsubstituted condensed ring.

Ar', Ar2 represents a nialyl group.

RIB, R1! , substituted or unsubstituted syntactic three types of groups;
Represents an alkyl group, an aryl group, and an araJrekyl group. or,
R18 and R19 may form a symcyclic ring with the nitrogen atom.

L lit represents an anion residue.

Typical specific examples of such azulenium salts include the following.

3. Noanine dye Noanine dye is known, for example, disclosed in JP-A-58-118.
No. 650, No. 58-224354, No. 59-1460
There is a compound described in No. 6.

4. Phthalonanine Compound Phthalocyanine compounds, which are one of the organic photoconductive materials, are known to have a photosensitive range extended to longer wavelengths than other compounds. Various crystalline forms of phthalonanine compounds have been discovered in the process of converting α-type phthalonanine compounds into stable crystalline β-type 7-talonanine compounds.

Examples of these phthalocyanine compounds exhibiting photoconductivity include X-type metal-free phthalocyanine compounds described in Japanese Patent Publication No. 49-4338, τ and τ described in JP-A Nos. 58-182639 and 60-19151. ', 111
' type metal-free phthalonanine compound, JP-A-63-148
In addition to the phthalocyanine compounds described in No. 269, various metal phthalocyanine compounds are exemplified.

For example, a patent application was filed in 1983 regarding titalphthalocyanine compounds.
There is one described in No.-241938.

In addition, examples of phthalocyanophthalocyanine exemplified compounds 5.7zo compounds and disazo compounds particularly suitable for semiconductor lasers include those shown in the following general formula.

General formula [G6): %Formula% In addition, as other azo compounds, there are those shown in the following general formulas.

General formula (G7): %Formula% General formula (G8): Cp-N=N-Ar"-N-N-Ar'-N=N-Cp
General formula (G9:l: Cp-N-N-Ar5-N-N-Ar'-N-N
-Ar'-N = N -CpHowever, Ar3, Ar',
Ar' represents the following two groups, each of which is capsubstituted or unsubstituted; a carbocyclic aromatic ring group and a heterocyclic aromatic ring group.

Furthermore, specific examples of Ar3, Ar', and Ar' are given below:
Examples of CPC couplers include the following.

However, as for A, in CGL, the content ratio of CGM to the binder substance is preferably 5/l - 1/10, and 3/l to 1/10.
It is more preferable to set it to 1/3.

When the content ratio of CGM is larger than the above range, black spots etc. tend to appear. However, if the proportion of CGM is too small, the photosensitivity etc. will actually decrease.

The thickness of the CGL is preferably 0.1-10 μm or more, more preferably 0.2-5 μm. It is preferable that the thickness of the CTL is 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.

Moreover, if the film thickness is larger than the above range, the residual potential will increase on the contrary, and, as in the case where the CGL is too thick, carriers will be caught by trap7 psite during movement, making it difficult to obtain sufficient transport ability. Therefore, the residual potential tends to increase during repeated use.

It is also possible to include CTM in CGL.

When PCL is formed by dispersing granular CGM, the CGM is preferably in the form of powder with an average particle size of 2IIm or less, preferably 1 μm or less, and more preferably 0.5 μm or less.

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. The layer is uniform and stable, resulting in better sensitivity and charging characteristics, and a photoreceptor that can form clear images with higher sensitivity can be used.

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

CTMs that can be used in the present invention include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, Pyrazoline derivatives, oxacilone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives,
1 selected from acridine derivatives, heptanazine derivatives, aminostilbene derivatives, triarylamine conductors, phenylenediamine derivatives, stilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc. It may be one species or two or more species.

Specific examples of such carrier transport substances are disclosed in JP-A-63
-50851.

The general formula is listed below.

The following general formula (TI) or [T2
] styryl compounds can be used.

General formula (TI): However, in this formula, R11, His, substituted or unsubstituted, represents two types of groups: an alkyl group, an aryl group, and the substituents include an alkyl group, an alkoxy group, a substituted amino group, and a hydroxyl group. , a halogen atom, and an aryl group are used.

Ar", Ar": represents a substituted or unsubstituted aryl group, and an alkyl group, alkoxy group, substituted amino group, hydroxyl group, halogen atom, or aryl group is used as a substituent.

R13, R26: Represents a substituted or unsubstituted aryl group or 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 (T2): However, in this formula, R25: substituted or unsubstituted aryl group, R26: hydrogen atom, hydrogen atom, three types of substituted or unsubstituted groups: alkyl group, alkokene group, amino group and hydroxyl group, R27: two types of substituted or unsubstituted groups; alkyl group,
Represents a heterocyclic group.

In addition, as CTM, the following general formulas [T3], [T4], [T
4a], (T4b) or [T5] can also be used.

General formula CT3): However, in this formula, Rjj and R2': each represent a hydrogen atom or a halogen atom, R, 30 and R31 each represent a substituted or unsubstituted aryl group, Ar17: represents a substituted or unsubstituted aryl group .

General formula (T4): However, in this formula, R32: represents three types of R-substituted or unsubstituted groups, a carbazolyl group, and a heterocyclic group; R33, R″4, and R3s: a hydrogen atom, an alkyl group, and a diaryl group. , represents two types of substituted or unsubstituted groups; an aryl group and an aralkyl group.

General formula (T4a): However, in this formula, R3' = methyl group, ethyl group, 2-hydroxyethyl group, or 2-chloroethyl group, R37: methyl group, ethyl group, benzyl group, or phenyl group, R38: methyl group, ethyl group, benzyl group or phenyl group.

However, in this formula, R31 is a substituted or unsubstituted 7-tyl group; R4'' is a substituted or unsubstituted alkyl group,
Aralkyl group, aryl group; R41 is a hydrogen atom, alkyl group or aryl group; R42 and R13 are the same or different groups consisting of a substituted or unsubstituted alkyl group, aralkyl group or aryl group.

General formula (T5): However, in this general formula, R'4 = two types of substituted or unsubstituted groups, nialyl group,
Heterocyclic group, R4S, hydrogen atom, two types of substituted or unsubstituted groups; alkyl group, aryl group, Q: hydrogen atom, halogen atom, alkyl group, substituted amino group, alkoxy group or cyano group, Sho or l Represents an integer.

Furthermore, a piazoline compound represented by the following general formula [T6] can also be used as the CTM.

General formula (T6): However, in this general formula, l: 0 or 11 R46 and R47: substituted or unsubstituted aryl group,
R4a = substituted or unsubstituted aryl group or heterocyclic group, R49 and R50: hydrogen atom, alkyl group having 1 to 4 carbon atoms, or substituted or device-substituted aryl group or aralkyl group (however, R49 and ROG are both (R4s is not a hydrogen atom, and when l is 0, R4s is not a hydrogen atom.) Furthermore, an amine derivative of the following general formula [T7] can also be used as a CTM.

General formula (T7): However, in this general formula, A "16, 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 S': 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. group, nitro group, piperidino group, morpholino group, naphthyl group, anthryl group and substituted amino group.

However, the substituent of the substituted amino group acyl group, alkyl group, ali Uses a metal group.

Furthermore, a compound of the following general formula [T8] can also be used as a CTM.

General formula (T8): %formula% However, in this general formula, Ar”: substituted or unsubstituted arylene represents the group, R51, B, sx, R53 and R64 : Three types of substituted or unsubstituted groups; Alkyl group, aryl group, aral Represents a kill group.

Furthermore, the compound of general formula [T9] can also be used as a CTM.

General formula (T9): However, in the general formula, Hss, R56, RS7 and HiRs
a is a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group,
Hensyl group or aralkyl group, R'' and Hie are each a hydrogen atom, a substituted or unsubstituted carbon atom number of 1 to 4
o alkyl group, cycloalkyl group, alkenyl group, cycloalkenyl group, aryl group or aralkyl group (provided that Rb2 and R2O jointly form a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms) ) R61, R62, R63 and Rb4 each represent a hydrogen atom, a halogen atom, a hydroquine group, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, or an amino group. , an alkylamino group or an arylamino group.

An antioxidant can be contained in CTL and CGL.

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, organic phosphorus compounds, and the like.

These specific compounds are disclosed in Japanese Patent Application Laid-Open No. 63-4466.
No. 2, No. 63-14153, No. 63-50849,
No. 63-18355, No. 63-58455, No. 63
-71856, 63-71855 and 66-1
It is described in No. 46046.

A polymer semiconductor can also be included in the photosensitive layer.

Among these polymeric organic semiconductors, poly-N-onylcarbazole or its semiconductor is most effective and is preferably used. Such poly-N-onylcarbazole derivatives mean that all or part of the carbazole ring in the repeating unit has various substituents, such as an alkyl group, a nitro group,
Substituted with an amino group, a hydroquine group, or a halogen atom.

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, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride,
Tetrabromo phthalic anhydride, 3-nitro phthalic anhydride,
4-nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzene, m-dinitrobenzene, 1,3.5-trinitrobenzene, paranitrobenzonitrile, Picryl chloride, quinone chlorimide,
Chloranil, brumanil, 2-methylnaphthoquinone, dichlordicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-
Fluorenylidene [dicyanomethylene malonodinitrile], polynitro-9-fluorenylidene [dicyanomethylene malonodinitrile], picric acid, 0-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid Examples include one or more compounds having a large electron affinity, such as pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds. Among these, fluorenone series, quinone series, and benzene derivatives having electron-withdrawing substituents such as CLCN and NO2 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 in the constituent layers of the photoreceptor include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, Evokin resin, polyurethane resin, polyester resin, alkyd resin, polycarbonate resin, and melamine resin. , addition polymer resins such as methacrylic resins, acrylic resins, polyvinidene chloride, polystyrene, polyaddition resins, polycondensation resins, copolymer resins containing two or more of these repeating units, vinyl chloride-vinyl acetate Examples include insulating resins such as copolymer resins, styrene-butadiene copolymer resins, vinylidene chloride-acrylonitrile copolymer resins, polymeric organic semiconductors such as N-vinylcannoxol, modified linicone resins, etc. can.

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

The binder for the protective layer provided if necessary has a volume resistivity of 108 Ω·cm or more, preferably 1Ol.

A transparent resin having a resistance of Ω·cm or more, more preferably 10 13 Ω·cm or more is used.

Further, the binder may be a resin that is cured by heat, and examples of the resin that is cured by heat include thermosetting acrylic resin, Epoquine resin, urethane resin, urea resin, polyester resin, alkyd resin, melamine resin, Alternatively, copolymerized or condensed resins thereof, and all other thermosetting resins used in electrophotographic materials may be used.

Further, if necessary, the protective layer may contain less than 50 wt % 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, Epoquin resin, polycarbonate resin, or copolymer resins thereof, polymeric organic semiconductors such as poly-N-vinylcarbazole, and other electrophotographic materials. All of the thermoplastic resins that are available are utilized.

CGL can be provided by the following method.

(a) A method in which a binder and a solvent are added to CGM, etc., and a mixed solution is applied.

(b) A method in which CGM, etc. is made into fine particles in a dispersion medium using a ball mill, homomixer, sand mill, ultrasonic disperser, 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 CTL can be formed by applying and drying the CTM described above alone or dissolved and dispersed together with the binder resin described above.

In this case, when CTM is contained in CGL,
There is a method of dissolving or dispersing CTM in advance in the solution of (a) or the dispersion of (b), ie, a method of adding CTM to CGL. In this case, the amount of CTM added is preferably within the range of 1 to 100 parts by weight per 100 parts by weight of the binder.

In addition, a solution containing CTM is applied onto the CGL, and the CGL
There is a method of diffusing CTM into CGL by swelling or partially dissolving CTM. If this method is adopted,
Although it is not necessary to add CTM to CGL as described above, it is also possible to carry out the two methods described above at the same time.

Solvents or dispersion media used to form the layer include butylamine, diethylamine, ethylenediamine, impropaturamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methylethylketonecyclohexanone, benzene,
Examples include toluene, xylene, chloroform, 112-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, impropatol, ethyl acetate, butyl acetate, dimethyl sulfoxide, and the like.

The above-mentioned PCL, UCL, OCL, 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, FIG. 5 shows an example of a recording apparatus using the photoreceptor of the present invention.

FIG. 6 is a flowchart of a reversal development method in electrophotography.

In the apparatus shown in Figure 5, 23 is a drum-shaped image carrier which has the above-mentioned organic photoconductive substances PCL8 and UCL7 and rotates in the direction of the arrow; 22 is an image carrier; the surface of 23 is uniformly charged; A charger, 24 is an image exposure device, and 15 is a developer.

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.

13 is a static eliminator consisting of one or a combination of a static eliminator lamp and a corona discharger for static elimination; 14 is a cleaning blade or fur plan for removing residual toner on the surface of the image carrier 23 after the image has been transferred; This is a cleaning device with

When the image exposure is performed using a semiconductor laser, it is preferable that the image exposure 24 be performed using a laser beam scanner in a recording apparatus that uses a drum-shaped image carrier 23 like the recording apparatus shown in FIG.

In addition, in a recording device in which the image carrier can be in a flat state, such as a belt-like image carrier, the image exposure can be made into 7-ratunyu exposure.

The method shown in FIG. 6 can be implemented using the recording apparatus as described above.

Figure 6 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 after electrostatic development. An example of reversal development performed by adhesion is shown.

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 0, and the obtained electrostatic image is developed by a developer 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, alkon, 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.

〔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, as shown in Table 1, U CLNo, U CL-
A total of 9 coating solutions from IE to 9E were prepared, each with a concentration of 0.6 pm.
The solution was filtered through a filter to obtain a coating solution for UCL.

These UCL coating liquids were applied to an aluminum drum (Funica LP).
-3010 for laser printer), 4mg/dm
The pulling speed was adjusted so that the UCL was formed.

UCL-IE is a phenoxy resin and is a blank.

For UCL-2E-UCL-6E, after dip coating,
While rotating the drum slowly, ultraviolet rays were irradiated for 60 seconds from a distance of about 50 c+o using a concentrating medium pressure mercury lamp with an output of 80 W/cm to form a UCL with a coating amount of 4 mg/dII+2.

For UCL-7E-DCL-9E, after dip coating,
Accelerating voltage 300KV while rotating the drum.

Using an ESI (curtain type) electron beam accelerator with a beam current of 10 to 15 mA, the absorbed dose is 3 to 10 Mr.
Electron beam irradiation was performed in the range of ad to form a UCL of 4 B/da.

Two of these UCL-coated drums were coated, one was coated with the next CGL multilayer coating, and the other was subjected to the adhesion test (baseline test) described later and the melt resistance test, followed by each CGL shown in Table 2.
40 g of cM was added to a polymer solution containing 40 g of each binder and 200 ml of each solvent, and dispersed for 12 hours using a sand grinder to prepare a fractional dispersion for CGL.

A cylinder having the above UCL is immersed in this dispersion, and C
Coating was performed at a coating speed of *# so that the amount of GL applied was 5 mg/dm2.

Table 2 Furthermore, 200 g of CTM shown in Table 3 and 450 g of the resin shown in Table 3 were added to 1,500 ml of 1,2-dichloroethane.
and apply to the obtained solution up to the CGL I;
Dip each drum, adjust the coating speed so that the film thickness is 200 μm, dry at 100°C for 1 hour, and coat with C.
A TL was formed to produce a laminated photoreceptor.

Table 3 The final laminated form of the photoreceptor is shown in Table 4, and will also be described below.

Electrophotographic properties and properties measured by the measurement method [Characteristics evaluation] Each of the photoreceptors of Examples and Comparative Examples was
It was installed on a modified 10J (manufactured by Konica) machine (equipped with a semiconductor laser light source), and the grid voltage was adjusted so that vM was -600±1O(V), and the potential of the exposed surface during irradiation with 0.711IW was V, development bias -500CV
), and the black spots on the white background of the image were evaluated.

Further, printing was performed 5,000 times, and V, , ■, after 5,000 times of printing was set to y, IoooSyLsooo.

Then, the displacement amounts of vM and vL from the initial stage are respectively A
V, “”, AVL”00.

Therefore, Δv M””−(v MSo”+600),
hVL""= (v Lsa'o -y L).

In addition, the evaluation of black spots (black spots) was performed by measuring the particle size and number of black spots using an image analysis device "Omnicon 3000" (manufactured by Shimadzu Corporation). Judgment was made based on the number of black spots per cm. The criteria for evaluating black spots are as shown in the table below.

Note that if the result of black spot determination is @ or ○, it is suitable for practical use, 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 UCL, after coating and drying UCL, it was immersed in methyl ethyl ketone for 30 seconds, and then observed using an electron microscope (SEM). UC of immersion surface
L indicates that the sample remains homogeneous, and ◎ indicates that the sample remains homogeneous, and △ or X indicates that the sample is heterogeneous or has dissolution or peeling.

The adhesion between UCL and PCL was evaluated by a substrate test. In other words, the distance between adjacent gaps is l
Using an 11 m contour guide, make 11 parallel scratches in the vertical and horizontal directions up to the conductive support with a cutter to form 100 squares (base squares). After attaching cellophane tape with a width of 24 mm on top of it, peel it off from one end. The number of squares that were peeled off at that time was counted and expressed as the number of squares that remained out of 100.

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

According to the results shown in Table 4, by using the resin of the present invention, it is possible to maintain good charging ability and sensitivity during repeated use, and to produce good images without black spots, as well as to produce a photoreceptor with excellent adhesion. I know that I can provide it.

On the other hand, when a comparative binder resin was used, part of the UCL dissolved after the CGL solution was applied, resulting in poor multilayer coating properties.
In addition, many black spots also occurred.

Next, photoreceptors similar to those in the above-mentioned example were prepared with a drum size for DC-8010 (manufactured by Konica). When images were produced on each of these photoreceptors using the DC-8010 under the following development conditions, good images without black spots were obtained under each development condition, regardless of which photoreceptor was used. It was done.

The development was carried out using so-called two-component non-contact jumping development.

Development conditions: 70 wt% magnetite powder with an average particle size of 0.1 μm, 3 Qvt% polyester resin as a binder resin,
The mixture is kneaded, crushed, granulated, and then classified to a particle size of 20 to 30 μm to form a carrier. The specific gravity of this carrier was about 3.5 or less. To this carrier, U-Bir 1800 (manufactured by Konica) toner for copying machine (toner containing carbon in polyester resin) was blended so that the toner concentration was 2Qwt%, and copying was performed under the following conditions.

The peripheral speed of the image carrier was 60 mm/sec, the gap between the image carrier and the developing sleeve was 0-3 mm, and the developer layer thickness was 0.05 m.
m, the diameter of the developing sleeve was 24++++a, and the rotation speed was 20 Orpm.

Regarding the developing bias and the like, the following three types of conditions were used.

[Brief explanation of the drawing]

1 to 7 are for explaining the embodiment, and FIG. 1(A) and FIG. 1 CB) are schematic diagrams schematically showing the movement of the carrier using a hand model, respectively; 2, 3, and 4 are cross-sectional views of a portion of each photoreceptor used in the present invention, FIG. 5 is a schematic diagram of an image forming apparatus, and FIG. 6 is a flowchart showing the process of image formation. FIG. 7 is a partial sectional view showing a conventional photoreceptor. FIG. 8 is an enlarged cross-sectional view of a part of another conventional photoreceptor. In addition, in the symbols shown in the drawings, ■... Conductive substrate 4... Carrier transport layer (CTL) 6.
...Carrier generation layer (CGL) 7...
. . . Undercoat layer (UCL) 8 . . . Photosensitive layer (PCL).

Claims (2)

[Claims] (1) A photoreceptor comprising at least a subbing layer and a photosensitive layer on a conductive support, wherein the subbing layer is formed of an epoxy radiation-curable resin. (2) The epoxy radiation-curable resin contains at least one of radiation-sensitive unsaturated double bonds such as acrylic double bonds, allylic double bonds, and maleic acid double bonds. Photoreceptor.