JPH0259767A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the electrostatic characteristics of the photosensitive body by using a material formed by drying and curing a specific org. titanium compd., silane coupling agent and polyvinyl butyral resin in an under coating layer. CONSTITUTION:The under coating layer is formed of the material formed by applying, drying and curing one kind of the org. titanium compd. selected from a group of the compds. expressed by the formulas I, II and III, the silane coupling agent and the polyvinyl acetal resin. In the formulas I to III, OR1-4 denote an alkoxy group, carboalkoxy group, etc.; n denotes 0 or >=1 integer; L denotes a chelate group, X denotes an ester group, etc.; n denotes 1 to 4 integer. The photosensitive body which has less dark attenuation, the excellent electrostatic characteristics and high contrast is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor comprising a substrate, an undercoat layer and a photosensitive layer, and particularly to an electrophotographic photoreceptor with an improved undercoat layer.

[Prior art] Conventionally, a copying machine using an electrophotographic method and an LED printer
Electrophotographic photoreceptors used in laser beam printers and the like have the following drawbacks.

(1) Dark decay is large and charging property is poor.

(2) It has optical memory properties such as residual charge.

(3)! The adhesive force between the plate and the photosensitive layer is weak, and the photosensitive layer peels off or floats when the photoconductor is handled, and the life of the photoconductor comes to an end before its electrostatic characteristic lifespan.

(4) Defects such as white spots, black spots, and pinholes occur on images due to chemical, physical, mechanical, and nonuniformity of the substrate.

In order to improve the above defects, an undercoat layer is applied on the substrate of several thousand amps.
It is known that the thickness is 50 μm.

Typical drag layers include resin layers, for example,
Polyvinyl alcohol, butyral resin, phenolic resin, melamine resin, polyurethane, polyamide, styrene-acrylic acid polymer, etc., and in some cases, crosslinked resins to which a curing agent and the like are added are used.

However, when these resin films are used as an undercoat layer,
The reality is that sufficient effects have not been achieved for the intended purpose.

In other words, if the undercoat layer is made thicker to improve chargeability,
The potential of the exposed area does not drop completely, the residual potential increases, and as a result, the electrostatic contrast decreases, resulting in a poor image.

Furthermore, photocarriers remain in the undercoat layer or charge generation layer,
Deterioration of chargeability and afterimage occur.

On the other hand, if the undercoat layer is made thinner, these problems can be reduced, but a -like resin film is not formed on the substrate, and the non-uniformity of the substrate surface is reflected, resulting in image defects.

On the other hand, carbon powder, metal powder such as AI, Au, Ag, or Zn is used as a conductivity control agent in the undercoat layer.
OSZ r O2, T I O2, I n 20, . 5
Attempts have been made to control and improve the resistance by controlling the thickness of the undercoat layer to a certain extent by incorporating metal oxides such as nOz, but due to poor dispersion, etc., the originally intended substrate surface Instead of improving the non-uniformity of the image, it has problems such as an increase in point defects on the image.

The charge-generating layer is usually made by mixing an organic pigment with a charge-generating function in a selected resin liquid or solvent, dispersing it in a ball mill, sand mill, etc., liquefying it, and coating it on the undercoat layer or the substrate. , obtained by forming a film. This wet coating method is a photoreceptor manufacturing method with excellent mass productivity, but there are many quality issues that require attention, such as the stability of the dispersion and impurities that may be mixed in during the preparation of the dispersion. A lot of effort is required.

One way to avoid this problem is to form a film of a heat-resistant charge-generating material by vacuum evaporation. Examples of charge-generating materials used in this method include quinacridone pigments, metal-free or various metal phthalocyanine pigments, squareium pigments, perylene pigments, and fused polycyclic charge-generating materials. Particularly suitable examples include Cu-phthalocyanine, Pb phthalocyanine, and ■-phthalocyanine.

Usually, the film thickness is 0.1 to 3.0μ, preferably 0.
．． It is 1 to 0.5μ. This film thickness is greatly influenced by the substrate surface, and when using a metal substrate, its material,
Surface roughness, degree of cleanliness, etc. must be carefully controlled.

Although a subbing layer can be used in this method as well,
A resin layer is preferred from the viewpoint of adhesion to the photosensitive layer. However, when selecting the resin material, it is necessary to remove adsorbed gases, moisture, solvents, and unreacted materials from the resin layer during the formation of the photosensitive layer under high vacuum.
You must choose one that has no emissions, such as, or one that has negligible emissions. In addition, when the substrate needs to be heated in forming the photosensitive layer, it is necessary to use a resin material having further heat resistance.

As mentioned above, a resin-dispersed undercoat layer can be used, but due to poor dispersion, or even if the dispersibility is good, the surface originally lacks smoothness, it is essentially a dispersion-type undercoat layer. is not suitable for forming a charge generation layer by vapor deposition.

Further, although JP-A No. 61-94057 discloses an undercoat layer made of an organometallic compound, the organometallic compound alone is not sufficient to solve the above-mentioned problems.

That is, an organic metal compound, an inorganic compound, an organic compound, or an organic polymer compound must be appropriately selected and added depending on the type and formulation of the charge generation layer in contact with the undercoat layer.

[Problems to be Solved by the Invention] A first object of the present invention is to provide a substrate, an undercoat layer, a charge generation layer,
It is an object of the present invention to provide a photoreceptor having a layered structure in which charge transfer layers are sequentially laminated, which exhibits less dark decay, excellent charging characteristics, and high contrast.

A second object of the present invention is to provide a photoreceptor having the same structure that has less residual charge or less charge accumulation.

A third object of the present invention is to provide a photoreceptor having the same structure in which image defects such as pinholes, white spots, and black spots are less likely to occur.

A fourth object of the present invention is to provide an electrophotographic photoreceptor having the same structure that is less susceptible to the influence of the substrate surface.

A fifth object of the present invention is to provide an electrophotographic photoreceptor having the same structure that has excellent adhesiveness between the substrate and the photosensitive layer.

A sixth object of the present invention is to provide a photoreceptor having the same structure, which has less environmental dependence and has excellent durability.

[Means for Solving the Problems] The present invention provides an electrophotographic photoreceptor in which an undercoat layer and a photosensitive layer are sequentially laminated on a conductive substrate, in which the undercoat layer comprises an organic titanium compound, a silane coupling agent, and a polyvinyl butyral resin. It consists of an electrophotographic photoreceptor characterized by being made of a dry and hardened material.

Organic titanium compounds usually have general formulas (1), (II), (I
At least one type is selected from the group of compounds represented by II).

OR R40-T i-0R2 OR.

(I) (In general formulas (1) and (II), OR and ~4 represent an alkoxy group, a carbalkoxy group, a phenoxy group, a sulfoxy group, or a phosphoxoxy group, and n represents an integer of 0 or 1 or more) (L) X4-
(III) (In the general formula (III), L is a chelate group, X is an ester group, and n is an integer of 1 to 4) Examples of the compound represented by the general formula (1) include tetramethyl orthotitanate, tetraethyl orthotitanate, , tetra-n-propyl orthotitanate, tetraisopropyl titanate, tetrabutyl orthotitanate, tetraisobutyl orthotitanate, tetracresyl titanate, tetrastearyl titanate, tetra-2ethylhexyl titanate, isopropyl triisostearyl titanate, isopropyl tridodecyl benzene Sulfonyl titanate, isopropyl-tris (
Examples include dioctyl pyrophosphate) titanate.

Examples of the compound represented by the general formula (n) include tetrabutyl polytitanate, tetracresyl polytitanate, and tetraacetylacetonate polytitanate. Examples of the compound represented by the general formula (III) include diisopropoxytitanium-
Examples include bis-octanediol, diisopropoxytitanium-bis-hexanediol, diisopropoxytitanium-bis(acetylacetonate), titanium tetralactate, titanium tetralactate ethyl ester, and tetratriethanolamine titanium chelate.

Other titanium compounds include titanium tetraammonium lactate, titanium tetraacetylacetonate ammonium lactate, tetraisopropyl-bis(dioctylphosphate) titanate, tetraoctyl-bis(ditridecylphosphate) titanate, and tetra(2) ,2-diaryloxymethyl-1-butyl)bis(butrybutyl phosphate)
Also included are titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, tris(dioctyl pyrophosphate) ethylene titanate, and the like.

In addition, as a silane coupling agent, general formula (R
1) m S l (OR6) 4-
0 (IV) (R5 and R6 are alkyl groups such as methyl group, ethyl group, propoxy group, butoxy group, phenyl group,
Vinyl group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, γ-mercaptopropyl group, and γ
-Aminopropyl group, γ (represents an amino group such as 2-aminoethylaminopropyl group, m represents 1 to 4)
A compound represented by is used.

For example, γ-methallyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-glycidoxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, Ethoxysilane, N-β (aminoethyl)
Examples include γ-aminopropylmethyldimethoxysilane, γ-aminobrobyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmonomethoxysilane, diphenyldimethoxysilane, diphenyljethoxysilane, and monophenyltrimethoxysilane.

The polyvinyl acecool resin used in the present invention includes:
In general, it contains the repeating 1 digit shown below, and there are many types of resins with different characteristics depending on the type of CH, CH3R.

For example, the following resins can also be selected.

H3 etc. In the present invention, the following polyvinyl butyral resins (
Vl) is one of the preferred ones.

Usually l is 50 to 80 mol%, m is 10% or less, n or 30
~50 mol% is preferred.

The pull layer contains at least one of the above (I), (n), and (III), (IV), and polyvinyl acecool resin (V
) is added with a solvent to form a coating solution, wet-coated, dried and cured, and formed on a conductive support. The function of the undercoat layer is
Electrically, a charge blocking layer is provided at the interface between the substrate and the charge generation layer to maintain chargeability and make it easier for photocarriers to reach the substrate, as well as to improve the adhesive strength between the two and to prevent various defects. The object of the present invention is to reduce defects on images caused by uniformity. The undercoat layer of the present invention has a thickness of 0.05 to 10 μm.
, preferably 0°2 to 5 μm, these objectives can be fully achieved.

That is, when the photosensitive layer is charged and exposed imagewise, the dark decay is small, so the exposed area (VL) and the unexposed area (Vo
), the contrast (Vo VL) is large, so an extremely sharp, high-density image can be obtained. Furthermore, since the photocarrier easily passes through the undercoat layer and reaches the substrate, image defects due to residual charges are significantly reduced. Furthermore, since it is a non-dispersed undercoat layer and has a certain film thickness, it is not affected by the non-uniformity of the substrate surface, resulting in an image with excellent resolution without image distortion. Furthermore, when a charge-generating material is further formed into a film by vapor deposition, the undercoat layer effectively improves the adhesive strength and improves mechanical durability.

In addition, in an LED printer or a laser beam printer that uses a laser beam of 780 nm or around 780 nm as a light source, for example, after negatively charging the photosensitive layer, image exposure is applied with long wavelength light to increase the potential of the exposed area (V+, ), and the difference (VD VL) between the non-exposed area potentials (Vo) and the development process in which an appropriate positive bias potential is applied during development and a negative polarity developer is attached to the low potential VL. Since the undercoat layer according to the invention has a small dark decay, a substantially large electrostatic contrast can be obtained, so that a high-contrast image can be obtained.

- Numerically speaking, charge-generating materials corresponding to this wavelength range generate a large amount of thermally excited carriers, so an undercoat layer with even higher blocking properties against carriers injected from the substrate is required. , sufficiently satisfactory results can be obtained with the undercoat layer made of the material of the present invention. The method for forming the undercoat layer is to dissolve the titanium compound, silicon compound, and polyvinyl butyral resin in a solvent, determine the dilution rate depending on the film forming method, and apply this solution by dipping coating, wire coating, blade coating, or knife coating. Apply and dry by coating, roll coating, screen coating, etc.

The photosensitive layer of the present invention is prepared by sequentially providing a laminated photoreceptor in which a charge generation material and a charge transfer material are separated on an undercoat layer of the present invention. A single-layer type photosensitive layer containing at the same time may be provided on the undercoat layer.

Alternatively, a reverse layer type photoreceptor in which the order of lamination is reversed or a photoreceptor in which a surface protective layer is provided as the top layer may be used.

The charge generating material used in the present invention is a-3e.

Inorganic charge generating materials such as a-3is CdS, 5e-Te, 5e-As, etc. may also be used.

The charge generating material used in the present invention is mainly an organic pigment, and the pigment is usually used in the form of particles.

Examples of charge-generating materials include phthalocyanine pigments, anthrone pigments, dibenzpyrene pigments, pyracitron pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, quinacrytone pigments, azulenium salt compounds, biryllium dyes, thiapyrylium dyes, cyanine dyes, Examples include particles of xanthine dyes, quinone imine dyes, triphenylmethane dyes, styryl dyes, selenium, selenite, cadmium sulfide, amorphous silicon, copper indium selenium, and the like.

Charge generating materials compatible with long wavelength light of 780 nm or around 780 nm include phthalocyanine pigments, azo pigments, disazo pigments, trisazo pigments, quinocyanine, azulenium salt compounds, biryllium dyes, thiapyrylium dyes, cyanine dyes, and xanthine dyes. , quinoneimine dyes, triphenylmethane dyes, styryl dyes, benzidine dyes, amorphous silicon, selenium,
Examples include copper indium selenium, copper indium tellurium, and the like.

For the charge generation layer, a charge generation material is formed by vapor deposition, etc.
The film is formed to have a thickness of 0.01 μm to 50 μm. Alternatively, a charge generating material and a resin solution or solvent with a particle size of 0.01μ
It is dispersed to a film thickness of 0.01 μm to 50 μm, coated and dried by methods such as dipping coating, spray coating, spin code, bead coating, Mayer bar code, blade coating, roller coating, curtain coating, etc. do.

As a binder, polyacrylate, methacrylic resin,
Vinyl chloride resin, polyamide, phenoxy resin, polyketone, polyacetal, polystyrene, vinyl acetate, phenol resin, epoxy resin, polyester resin, polyvinyl ketone, polyN-vinylcarbazole, polyvinyl.

acrylamide, alkyd resin, polycarbonate, polyurethane, cellulose resin, polyvinyl alcohol, aldehyde-modified polyvinyl alcohol, or copolymers thereof, such as styrene-butadiene copolymer,
Any insulating and adhesive resin such as a condensation resin such as a styrene-acrylonitrile copolymer or a vinyl polymer can be used.

Examples of plasticizers include halogenated paraffins, polychlorinated biphenyls, dimethylnaphthalene, and dibutyl phthalate. In addition, silicone oil or the like may be added to improve the surface properties of the photoreceptor.

The ratio of charge generating material and binder is 1/100 to 5 by weight.
00/100, preferably 3/7 to 7/3.

Charge transfer substances include hole transfer substances and charge transfer substances. Examples of the hole transfer substance include the following compounds.

9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone, 9-ethylcarbazole-
3-aldehyde-1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1,1-
diphenylhydrazone, 4-diethylaminostyrene-
β-aldehyde 1-methyl-1-phenylhydrazone,
4-methoxynaphthalene-1-aldehyde 1-benzyl-1-phenylhydrazone, 4-methoxybenzaldehyde 1-methyl-1-phenylhydrazone, 2.4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde 1,
1-diphenylhydrazone, tris(4-diethylaminophenyl)methane, 1.1-bis(4-dibenzylaminophenyl)propane, 9-(4-diethylaminostyryl)anthracene, 9-(4-diethylaminobenzylidene)fluorene, 3 - (9-fluorenylidene)-9-ethylcarbazole, 1,2-bis(4-diethylaminostyryl)benzene, 3-styryl-9-ethylcarbazole, 3-(4-methoxystyryl)-9
-ethylcarbazole, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, 4'-diphenylamino-α-phenylstilbene, 1-phenyl-3-(
4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, 1-phenyl-3-(4-
Low molecular weight compounds such as dimethylaminostyryl)-5(4-dimethylaminophenyl)pyrazoline, 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, tri-p-tolylamine, triphenylamine, etc. There is. Further, polymer compounds such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, and ethylcarbazole formaldehyde resin can also be used.

Examples of electron transfer substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4.7-dolinitro-9-fluorenone,
2,4.5.7-tetranitro-9-fluorenone, 2
,4,5゜7-tetranitroxanthone,2,4.8-
Trinidrothioxanthone, 2,6.8-trinitro-
4H-indeno[1,2-b]thiophen-4-one,
Examples include 1,3,7-trinitro 5°5-dioxide.

These charge transfer substances may be used alone or in combination of two or more PIs.

Examples of binders include polyacrylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin,
Examples include methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, and copolymers thereof.

In the charge transfer layer, the ratio of the charge transfer agent to the binder resin is 5/100 to 500/100 by weight.

When the charge transfer layer is dissolved in a solvent together with a charge transfer agent or a binder and a layer is formed by coating, dip coating,
Spray coat, spinner coat, bead coat, Meyer barcode, blade coat, roller coat,
This can be done using a coating method such as curtain coating.

A photosensitive layer formed by laminating such a charge generation layer, a charge generation layer and a charge transfer layer, or a charge transfer layer and a charge generation layer in this order is provided on a substrate having a conductive layer.

As the substrate having the conductive layer, materials that are conductive themselves such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc. can be used. , as well as aluminum, aluminum alloy,
Plastics with a layer formed by vacuum evaporation of indium oxide, indium oxide-tin oxide, etc.
(e.g., polyethylene, polypropylene, vinyl chloride resin, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc.), conductive particles (e.g., carbon black, silver particles, tin oxide particles, tin oxide coated titanium oxide particles, etc.) in an appropriate binder. In addition, a substrate coated on plastic, a substrate made of plastic or paper impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used.

[Example] Examples of the present invention will be shown below to explain the present invention in further detail.

Example 1 Three parts of titanium tetrabutoxide, 1 part by weight of γ-methacryloxypropyltrimethoxysilane, and polyvinyl butyral resin (manufactured by Shimizu Chemical Co., Ltd., S-LEC BL-1)
) was dissolved in 80 parts by weight of butanol to prepare an undercoat layer coating solution. This coating solution was dip-coated onto an Al plate whose surface had been cleaned, and dried and cured at 120° C. for 30 minutes to form a 1.0 μm undercoat layer.

A dispersion obtained by pulverizing and mixing 98 parts by weight of tetrahydrofuran in a ball mill was applied onto an Al plate with a subbing layer using a doctor blade, and air-dried to a thickness of about 1.
．． A charge generation layer of 0 μm was formed.

Next, 1 part by weight of a charge transfer material having the following structural formula, 1 part by weight of polycarbonate (Panlite -1300 manufactured by Tijin Co., Ltd.), and 8 parts by weight of methylene chloride were dissolved. This was applied onto the charge generation layer using a doctor blade, and heated at 120°C for 30 minutes.
After drying for 0 minutes, a charge transfer layer of 18 μm was formed, and a laminated photoreceptor was obtained.

This photoreceptor was negatively charged by performing -6KV corona discharge for 20 seconds using an electrostatic copying paper testing device (Kawaguchi Electric Seisakusho, Model 5P-428), and the surface potential at that time was Vm, 20 Leave it in a dark place for a second, and then the surface potential V
o (V), and then the surface was irradiated with light using a tungsten lamp so that the illumination intensity was 4.51×φSeC, and the surface potential was 1/2 V.

Find the time (s e c) until the exposure becomes ff1E
Calculate 1/2 (lx-sec). Sono result Vm=
−980V, El/2−0.511×”sec, and dark decay rate Vo/Vm=0.79.

Comparative Example 1 A photoreceptor was prepared using the same recipe as in Example 1 except that the undercoat layer was a resin-dispersed coating film shown below.

That is, conductive titanium oxide (Mitsubishi Metals W-10) 2
Part by weight: 1 part by weight of polyamide (CM-8000 manufactured by Toshi) was mixed with 50 parts by weight of a mixed solvent of ethanol and butanol, and the coating solution was dispersed in a ball mill and coated with a blade on a cleaned Al plate, and heated at 120°C at 30°C. Dry for 4.0 minutes
A photoreceptor was prepared using the same recipe as in the example except that a μ subbing layer was provided.

The evaluation results are V m = -890V, E 1 /
2-0, 611 x-sec, Vo/Vm-
It was 0.49.

Example 2 4 parts by weight of tetraisopropyl titanate, polyhydroxy titanium stearate (Matsumoto Kosho Orgatics TPH)
3) 1 part by weight, 1 part by weight of methyltriethoxysilane, and 4 parts by weight of polyvinyl butyral resin (same as in Example 1) in a mixed solvent of ethanol, n-butanol, and toluene (
1:1:3) dissolved in 100 parts by weight and washed A
It was dip coated on a plate and dried at 120°C for 1 hour to form a 3.0μ undercoat layer.

A mixed solution of 5 parts by weight of a disazo pigment having the following structural formula and 95 parts by weight of cyclohexanone was crushed and dispersed in a ball mill for 48 hours, and further cyclohexane was added to dilute it until the weight ratio of pigment to solvent was 2/98. Further, the mixture was dispersed in a ball mill for 24 hours to obtain a coating liquid. Methyl ethyl ketone is added to this solution, and the weight ratio of pigment to solvent is 1/
Diluted to 99%.

Next, it was coated on an Al plate provided with an undercoat layer using a doctor blade and air-dried to form a charge transfer layer with a thickness of about 0.8 μm.

On the other hand, as a charge transfer layer, a charge transfer material 1 having the following structural formula is used.
Part by weight, 1 part by weight of polycarbonate (same as in Example 1) was dissolved in 8 parts by weight of methylene chloride, applied with a doctor blade, dried at 120°C for 30 minutes to form a charge transfer layer of 20μ, and a laminated type. A photoreceptor was obtained.

When this photoreceptor was evaluated for electrostatic properties in the same manner as in Example 1, it was found that Vmm -1310VSE 1/2 - 0.671x
-sec. Vo/V--0,93 Comparative Example 2 In Example 2, except that the undercoat layer of Comparative Example 1 was provided.
Other than that, a photoreceptor made with the same recipe was prepared and evaluated in the same way. Vmm-1050, E 1/2-0
．． 641 x-sec.

Vo/Vrr+-0.81.

Example 3 Titanium acetylacetonate (Matsumoto Music, Orgatex TC100, (C3H70) 2T L (C5
H70□) 2) 2 parts by weight, 1 part by weight of γ-glycidoxypropyltrimethoxysilane, and 2 parts by weight of polyvinyl butyral resin (BX-L manufactured by Block Chemical Industry Co., Ltd.) were dissolved in 80 fffm parts of n-butanol and washed. Dip coat the finished AI board and dry at 130℃ for 1 hour to obtain a coating of 3.0
A μ subbing layer was formed. Next, high-purity α-type copper phthalocyanine (manufactured by Toyo Ink) was vacuum-deposited to provide a 0.3 μm charge generation layer on the A1 plate provided with the undercoat layer.

Further, 1 part by weight of a charge generating material having the following structural formula and 1 part by weight of polycarbonate (Example 1) were dissolved in 8 parts by weight of methylene chloride. This liquid was applied onto the charge generation layer using a doctor blade to form a charge transfer layer with a thickness of 19 μm.

When the electrostatic characteristics of this photoreceptor were evaluated, it was found that Vm-
-890V.

El/2=1.011x・ s e c, Vo/Vm = 0.85.

The results are shown in the table below.

Comparative Example 3 A photoreceptor was prepared with the same formulation as in Example 3 without providing an undercoat layer, and the same evaluation was performed.
10V, El/2=0.811x-sec. V
o/V, -0.64 Example 4 In Examples 1 to 3 and the photoreceptors having the layer configurations of Examples 1 to 3, drum-shaped photoreceptors were produced by replacing the AI plate with a cylindrical support. The photoreceptors of Example 1 and Comparative Example 1 were heated to a wavelength of 780n.
It was attached to an electrostatic copying printer having a laser light source of 500 m to output an image pattern. Also, Example 2.3,
The photoreceptor of Comparative Example 2.3 was attached to a copying machine using a halogen lamp as a light source, and an image was formed. Furthermore, ten scratches each having a length of 10 mm were made with a knife on the surface of this drum-shaped photoreceptor, and a peeling test using tape was performed. As a result, the photosensitive layer of Comparative Example 3 was easily peeled off, but the photosensitive layers of Examples 1.2.3 were not peeled off at all.

[Effects of the Invention] As explained above, by providing the undercoat layer of the present invention, the electrostatic properties of the photoreceptor are improved, and clear images with high density and high contrast without abnormalities can be obtained.
A photoreceptor with excellent adhesive strength can be obtained.

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor in which an undercoat layer and a photosensitive layer are sequentially laminated on a substrate, the undercoat layer is made of a material obtained by coating, drying, and curing an organic titanium compound, a silane coupling agent, and a polyvinyl acetal resin. An electrophotographic photoreceptor characterized by: (2) The organic titanium compound has the following general formula (I) or (II)
The electrophotographic photoreceptor according to claim 1, which is at least one compound selected from the group of compounds represented by (III). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In general formulas (I) and (II), OR_1_-_4 are alkoxy groups, carbalkoxy groups, phenoxy groups , sulfoxy group, phosphooxy group, n is an integer of 0 or 1 or more) Ti(L)_nX_4_-_n(III) (In general formula (III), L is a chelate group, X is an ester group, and n is 1 to 4 integer)