JP3295196B2 - Electrophotographic photoreceptor and electrophotographic apparatus provided with the electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus provided with the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art An electrophotographic process comprises the steps of: uniformly charging a photosensitive member having at least a photosensitive layer on a conductive support;
It is composed of latent image formation by exposure, formation of a developed image by toner, transfer to a transfer material mainly composed of paper, and removal (cleaning) of transfer residual toner. The electrophotographic photoreceptor used here is required to have required sensitivity, electric characteristics, and optical characteristics according to the electrophotographic process to be applied. Since the surface of the photoreceptor is directly applied with an electrical or mechanical external force such as charging, toner development, transfer to paper, and cleaning of the remaining toner, resistance to the external force is required. Specifically, in the case of using scratches and abrasions caused by rubbing, and corona charging, resistance to chemical degradation due to ozone generated particularly under high humidity is required. Further During repetition of the residual toner to be performed the cleaning, the toner adhesion of the photosensitive member surface, because of the blade turn such problems in performing blade cleaning, surface slipping property, releasing property, such as stain resistance properties are required You.

[0003] In order to meet such demands, formation of a protective layer on a photoreceptor has been widely proposed. As a material of the protective layer, a resin having excellent release properties and slipperiness represented by a fluororesin, and a resin material having a high hardness represented by an acrylic resin have been studied.

[0004] However, a material satisfying the above-mentioned various properties has not yet been found. For example,
The hardness of the fluorine resin alone is so low that it is difficult to suppress the generation of scratches. Further, since it is hardly soluble in general solvents, film formation is not easy. In this case, a method of dispersing the fluororesin as a fine powder in a suitable binder has been proposed, but there is a problem that the image quality is deteriorated due to light scattering of these particles.

[0005] On the other hand, high-hardness resins such as crosslinkable acrylics are not sufficient in terms of slipperiness, electrical properties under high humidity, and mold releasability. In addition, these general radical polymerization systems have poor curing on the film surface due to polymerization inhibition curing by oxygen in the air, and breakage of carbon-carbon bonds by light irradiation when using a photoinitiator. Only a cured product having unstable electric characteristics can be obtained. Therefore, there have been problems such as a decrease in transfer efficiency due to an increase in surface free energy and an image blur due to moisture absorption.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photosensitive member which meets the above-mentioned requirements. That is, it provides a protective material having excellent abrasion resistance, hardness enough to prevent scratches, etc., and also excellent contamination resistance and mold release properties. An object of the present invention is to provide an electrophotographic photoreceptor using a protective material which does not change much and does not lower the intrinsic electrophotographic characteristics of the photoreceptor.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a positively or negatively chargeable electrophotographic photosensitive member having at least a photosensitive layer and a protective layer on a conductive support, wherein the protective layer comprises a thermionic polymerizable functional group. An electrophotographic photoreceptor is formed by applying a solution containing a compound having two or more epoxy groups and conductive metal oxide fine particles onto a photosensitive layer and then heating and polymerizing the solution.

When the electrophotographic photosensitive member of the present invention is manufactured,
As the conductive support, a cylindrical cylinder or a film of a metal or alloy such as aluminum or stainless steel, or a plastic coated with conductive coating is used.

An undercoat layer having a barrier function and an undercoat function can be formed on the conductive support. The undercoat layer is formed for the purpose of improving the adhesion and coating properties of the photosensitive layer, protecting the support and covering defects, and improving the injection property from the support. Usually, after dissolving the material in a suitable solvent, coating on a support,
It is dried to form a thickness of 0.2 to 2 μm. Materials include polyvinyl alcohol and poly-N-vinylimidazo-
, Polyethylene oxide, ethylcellulose, methylcellulose, ethylene-acrylic acid copolymer, polyamide and the like are known, but not limited thereto.

As the photosensitive layer, a photosensitive layer having a laminated structure of a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, and a single layer containing a charge generating substance and a charge transporting substance There is a photosensitive layer consisting of

Representative examples of the charge generating substance include phthalocyanine pigments and azo pigments, but are not particularly limited, and may be selected as long as required electrophotographic characteristics can be achieved. Usually, the charge generation layer is formed to a thickness of 2 μm or less by applying a dispersion of the charge generation substance in a solvent in which a suitable binder resin is dissolved and applying the dispersion. Examples of the binder resin include resins such as polycarbonate, polyacrylate, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-acrylonitrile copolymer, polyvinyl acetate, cellulose acetate, and polyvinyl butyral. No.

Examples of the charge transport material include compounds having a nitrogen-containing heterocyclic nucleus such as oxazole, thiazole and imidazole, pyrazoline compounds, polyarylalkane compounds, hydrazone compounds, triarylamine compounds, Examples include, but are not limited to, styryl compounds and carbazole compounds. The charge transport layer is formed by dissolving the above-described charge transport material and a suitable binder resin in a solvent, and applying this solution to form a 5 to 50 μm
It is formed thick. Examples of the binder resin include polycarbonate, polyacrylate, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene-butadiene copolymer, polyvinyl acetate, polyvinyl carbazole, silicone resin, polyester, and phenol. But not limited thereto, such as resin, polyurethane resin and epoxy resin.

The protective layer according to the present invention comprises a compound having two or more epoxy groups as thermionic polymerizable functional groups on the photosensitive layer, conductive metal oxide fine particles, and, if necessary, an ionic type. The coating is performed by applying a coating liquid mixed with a polymerization catalyst, heating and curing to form a laminate.

Tables 1 to 5 show specific examples of two or more epoxy groups as thermionic polymerizable functional groups used in the present invention, but the present invention is not limited thereto.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

These compounds may be used alone or as a mixture of two or more kinds, and may be used as a mixture with a compound having a functional group other than epoxy. Furthermore, a single molecule may have two or more different functional groups.

In order to polymerize the compound having a thermionic polymerizable functional group, an ionic polymerization catalyst can be added. Examples thereof include acid anhydrides, amines such as aromatic diamines, and other inorganic or organic compounds. Examples include acids and bases, but are not particularly limited.

The conductive metal oxides used in the present invention include zinc oxide, titanium oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide. And the like, but are not limited to these. These metal oxides may be used alone or as a mixture of two or more types. When two or more types are mixed, a solid solution may be used.

Generally, when particles are contained in the outermost layer of the photoreceptor, in order to prevent scattering of the incident light by the particles, the particle diameter of the particles must be smaller than the wavelength of the incident light, that is, 0.3 μm.
m. However, in order to prevent the formation of secondary particles due to agglomeration of the metal oxide fine particles in the resin that is left after the particles are dispersed, the average particle diameter must be further reduced. That is, by setting the average particle diameter of the primary particles to 0.05 μm or less, a dispersion liquid that is stable over time without aggregation of particles can be obtained.
Moreover, a highly transparent coating film can be obtained.

The above-mentioned conductive metal oxide is added for the purpose of controlling the electric resistance of the coating film in order to prevent the residual potential from increasing when the photoreceptor is used repeatedly. However, in a high-humidity environment, the electrical resistance of the film is reduced more than necessary due to moisture absorption on the metal oxide and its surface, and as a result,
May cause image blur. In order to prevent such a phenomenon, it is effective to subject the surface of the metal oxide to hydrophobic treatment with an organic silicon compound. Generally, a hydroxyl group is present on the surface of a metal oxide by hydration, and MO-Si is formed by a condensation reaction with silanol, silyl chloride, silyl hydride, silyl alkoxide, or the like.
A hydrophobic group such as an alkyl group, a fluoroalkyl group, or an aryl group bonded directly to a silicon atom to form a bond expresses the hydrophobicity of the metal oxide surface. Therefore, the organosilicon compound used in the hydrophobizing treatment may have a substituent capable of undergoing a condensation reaction with the hydroxyl group on the surface of the metal oxide as described above and a hydrophobic substituent directly bonded to a silicon atom. It is not limited.

Examples of the method of dispersing the metal oxide include a homogenizer, a ball mill, a vibration ball mill, a sand mill, a roll mill, and an ultrasonic wave. If there is, it is not particularly limited.

As a method for applying a coating solution containing a compound having a thermionic polymerizable group and metal oxide fine particles, a spraying method, a dipping method, a roll coating method and the like can be mentioned. It is only required to be obtained, and there is no particular limitation. After the polymerization reaction by heat treatment, the thickness of the coating film is 0.1.
About 5 to 10 μm is desirable.

Further, the present invention comprises an electrophotographic apparatus provided with the above-described electrophotographic photoreceptor of the present invention.

Next, an electrophotographic apparatus equipped with the electrophotographic photosensitive member of the present invention FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image carrier, and a shaft 1a
, And is driven to rotate at a predetermined peripheral speed in the arrow direction. The photoreceptor 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then, in an exposure section 3, a light image exposure L (slit exposure / (Laser beam scanning exposure, etc.). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor. The electrostatic latent image is then toner-developed by a developing unit 4, and the toner-developed image is transferred between the photosensitive member 1 and the transfer unit 5 by a transfer unit 5 from a paper feeding unit (not shown).
Are sequentially transferred onto the surface of the transferred transfer material P fed in synchronization with the rotation of. The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out as a copy (copy) outside the machine.
The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the transfer residual toner by the cleaning means 6, and is subjected to static elimination by the pre-exposure means 7, and is repeatedly used for image formation. As the uniform charging means 2 for the photoreceptor 1, a corona charging device is generally widely used. Also, the corona transfer means is generally widely used for the transfer device 5. As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is detachably attached to the apparatus body. You may comprise. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using guide means such as rails of the apparatus body. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit. When the electrophotographic apparatus is used as a copying machine or a printer, the light image exposure L uses reflected light or transmitted light from a document, or reads a document and converts it into a signal. This is performed by scanning a beam, driving a light emitting diode array, or driving a liquid crystal shutter array.

[0024]

【Example】

Example 1 10 parts by weight of 6-nylon were dissolved in 150 parts by weight of isopropanol and dip-coated on an aluminum cylinder.
An undercoat layer having a thickness of 0.8 μm was formed.

Next, 10 parts by weight of a bisazo pigment having the following structure:

Embedded image 5 parts by weight of polyvinyl butyral (molecular weight 25000),
200 parts by weight of cyclohexanone was dispersed in a sand mill, and this dispersion was dip-coated on the undercoat layer.
After drying at 00 ° C. for 20 minutes, a charge generation layer having a thickness of 0.08 μm was formed.

Next, 10 parts by weight of a triphenylamine compound having the following structure:

Embedded image 10 parts by weight of polycarbonate A (molecular weight: 25,000) was dissolved in 80 parts by weight of chlorobenzene, and this solution was applied onto the charge generation layer by dip coating, dried at 100 ° C. for 60 minutes, and charged to a thickness of 20 μm. A transport layer was formed.

Then, Compound Example 4 (n = 2) 60 in Table 1
30 parts by weight of tin oxide having an average primary particle diameter of 0.035 μm were put into 280 parts by weight of a 1: 1 mixed solvent of isopropanol and ethanol, and dispersed in a sand mill for 50 hours. 6 parts by weight of a diamine compound having the following structure

Embedded image Was added. After dip-coating the prepared solution on the photoreceptor formed up to the charge transport layer, the solution was heated at 80 ° C. for 30 minutes at 130 ° C.
For 120 minutes to form a protective layer having a thickness of 3.5 μm. At this time, the dispersibility of the prepared solution was good, and the surface of the protective layer was uniform without any unevenness.

Example 2 The tin oxide of Example 1 was treated on the surface with perfluorooctyltrimethoxysilane, and the others were the same as in Example 1.
An electrophotographic photosensitive member having a protective layer was prepared in the same manner as in the above.

Example 3 Examples of compounds shown in Table 1 in place of the epoxy resin in Example 2
7 and an acid anhydride having the following structure as a curing catalyst

Embedded image Was used to form a protective layer to prepare an electrophotographic photoreceptor.

Example 4 An undercoat layer was formed in the same manner as in Example 1, and
5 parts by weight of the bisazo pigment used in Example 1, 10 parts by weight of the triphenylamine compound used in Example 1, and 10 parts by weight of polycarbonate Z (molecular weight: 20,000) were mixed with 75 parts by weight of chlorobenzene. -Dip coating using a coating liquid dispersed for 20 hours in
After drying at 60 ° C. for 60 minutes, a single-layer photosensitive layer having a thickness of 20 μm was formed. Next, a protective layer was formed on the photosensitive layer in the same manner as in Example 2 to prepare a positively charged electrophotographic photosensitive member.

Comparative Example 1 An electrophotographic photosensitive member was prepared by forming up to the charge transport layer in Example 1, and used as a comparative sample.

Comparative Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that tin oxide was not added to the protective layer, and used as a comparative sample.

The electrophotographic photoreceptors prepared in Examples 1 to 4 and the electrophotographic photoreceptors prepared in Comparative Examples 1 and 2 were used as samples, and these were used as commercially available negative-charge type copying machines (trade name NP3).
525 (manufactured by Canon Inc.), and an image output test and a durability test were performed. Further, the photoconductor of Example 4 is NP3
525 was subjected to image output and a durability test using a copier modified for positive charging. The results are shown in Tables 6 and 7.

[Table 6]

[Table 7]

As described above, it can be seen that the combination of the epoxy resin and the conductive metal oxide whose surface has been hydrophobized has the highest abrasion resistance and maintains high image quality independent of the environment.

EXAMPLE 5 10 parts by weight of a charge-transporting substance having the following structure was placed on an aluminum cylinder having an undercoat layer formed in the same manner as in Example 1.

Embedded image And polycarbonate A (average molecular weight 22,000) 1
A solution prepared by dissolving 0 parts by weight in 60 parts by weight of chlorobenzene is applied by dip coating, dried at 120 ° C. for 60 minutes, and
A 0 μm charge transport layer was formed.

Next, 4 parts by weight of a bisazo pigment having the following structure:

Embedded image 2 parts by weight of polyvinyl benzal and cyclohexane 3
After dispersing 0 parts by weight in a sand mill for 40 hours, 60 parts by weight of methyl ethyl ketone was added to prepare a dispersion. The dispersion was spray-coated on the charge transport layer,
After drying for 5 minutes, a charge generation layer having a thickness of 0.09 μm was formed.

Next, the same protective layer as in Example 2 was formed, and a positively charged electrophotographic photosensitive member was prepared.

Example 6 Compound 16 shown in Table 4 and tin oxide hydrophobically treated with an organosilicon compound and the diamine compound used in Example 1 were placed on a photoreceptor formed up to the charge generation layer in the same manner as in Example 5. A protective layer was formed by applying a dispersion prepared in the same manner as in Example 1 to prepare a positively charged electrophotographic photosensitive member.

The electrophotographic photosensitive member was transferred to the copying machine NP35.
25 was mounted on a copier modified for positive charging, and an image output and durability test were performed. Usually, such a positively charged electrophotographic photosensitive member has poor durability due to its structure.
It had durability of more than 10,000 sheets.

[0040]

The electrophotographic photoreceptor of the present invention has a remarkable effect that a stable image with good image quality can be continuously obtained regardless of the use environment.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoreceptor as an image carrier (electrophotographic photoreceptor of the present invention) 2 Corona charging device 3 Exposure unit 4 Developing unit 5 Transfer unit 6 Cleaning unit 7 Pre-exposure unit 8 Image fixing unit L Light image exposure P Transfer material after image transfer

Continued on the front page (72) Inventor Tatsuya Ikezue 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shoji Amemiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor: Kimihiro Yoshimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-55-64250 (JP, A) JP-A-4-271357 (JP) JP-A-4-97160 (JP, A) JP-A-4-311964 (JP, A) JP-A-4-3388961 (JP, A) JP-A-3-139655 (JP, A) 3-135573 (JP, A) JP-A-5-265244 (JP, A) JP-A-62-295066 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/147 502

Claims (4)

(57) [Claims] Having a claim 1, wherein at least a photosensitive layer and a protective layer on a conductive support, the positive or negatively chargeable electrophotographic photoconductor, the protective layer is a thermal ion-polymerizable functional groups
An electrophotographic photoreceptor formed by applying a solution containing a compound having two or more epoxy groups and conductive metal oxide fine particles on a photosensitive layer and then heating and polymerizing the solution. 2. The electrophotographic photoreceptor according to claim 1, wherein the average particle size of the primary particles of the conductive metal oxide fine particles is 0.05 μm or less. Wherein the conductive metal oxide electrophotographic photosensitive member surface according to claim 1 or 2 is hydrophobized by organic silicon compound fine particles. 4. The electrophotographic apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 3.