JPH0619176A - Electrophotographic sensitive body, and electrophotographic apparatus and facsimile provided with the same - Google Patents

Abstract

PURPOSE:To obtain superior lubricity and to suppress occurrence of abrasion wear and scratches and to improve durability by dispersing a phosphazene resin and fine metal oxide particles surface-treated with a specified silicon acrylate into a protective layer. CONSTITUTION:The ultrafine metal oxide particles are surface-treated with the silicon acrylate represented by expression I and dispersed into a resin containing the phosphazene resin obtained from a phosphazene hardenable monomer high in polarity represented by expression II to form a stable well- dispersible coating fluid, thus permitting the obtained protective film to be excellent in environmental conditions. In expressions I and II, R1 is 1-6C alkylene; each of R2-R4 is H or 1-4C alkyl; each of R5-R7 is H or methyl; and R8 is alkyl, aryl, alkylated aryl, alkylamido, arylamido, or polyoxyalkylene.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member, and more specifically, an electrophotographic photosensitive member having a surface protective layer and the electrophotographic photosensitive member. The present invention relates to an electrophotographic device and a facsimile.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is required to have required sensitivity, electric characteristics and optical characteristics according to an electrophotographic process to be used. As for the surface layer of the photoconductor, that is, the layer most distant from the substrate, electrical and mechanical external forces such as corona charging, toner development, transfer to paper, and cleaning are directly applied, Durability against them is required. Specifically, the occurrence of surface wear and scratches due to rubbing,
In addition, durability against deterioration of the surface due to ozone generated during corona charging is required. On the other hand, there is a problem that the toner adheres to the surface layer due to repeated development cleaning of the toner, and to this end, it is required to improve the cleaning property of the surface layer.

In order to satisfy the properties required for the surface layer as described above, attempts have been made to provide a surface protective layer containing a resin as a main component. For example, as disclosed in JP-A-57-30843, there has been proposed a protective layer in which a resistance is controlled by adding a metal oxide as a conductive powder.
However, the conventionally used methods have problems in dispersibility of the metal oxide particles in the binder resin, cohesiveness, conductivity when used in the protective layer, and transparency, and unevenness of the protective layer surface. Image defects due to unevenness, increase in residual potential due to repeated charging, and decrease in sensitivity were likely to occur. Further, in order to impart transparency and conductivity uniformity to the protective layer, it is more useful to disperse ultrafine particle powder (primary particle size: 0.1 μm or less). It is difficult to stably disperse the resin in the resin more than the fine particles (primary particle size to 0.5 μm or more), secondary aggregation progresses with time, the dispersed particle size increases, and transparency and conductivity uniformity decrease. There was a problem. Further, particularly under high humidity, ozone, corona products such as NO _x, etc. generated by repeated charging adhere to the surface, which causes a reduction in the surface resistance of the photoconductor, resulting in image deletion (image blur). Due to the above problem, a protective layer having satisfactory electrophotographic characteristics has not yet been obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member which is excellent in slipperiness and has durability against abrasion of the surface due to rubbing and generation of scratches. Another object of the present invention is to provide an electrophotographic photosensitive member capable of maintaining high-quality image quality even under high humidity without causing reduction in surface resistance due to adhesion of corona products repeatedly generated in the electrophotographic process. . Further, another object of the present invention is to provide an electrophotographic photosensitive member exhibiting stable electrophotographic characteristics without accumulation of residual potential and deterioration of sensitivity in repeated electrophotographic processes. Another object of the present invention is to provide an electrophotographic apparatus and a facsimile equipped with the above electrophotographic photosensitive member.

[0005]

The present invention is an electrophotographic photoreceptor having a photoconductive layer and a protective layer on a conductive support, wherein the protective layer is a phosphazene resin and a silicon acrylate represented by the following general formula (1). It is composed of an electrophotographic photosensitive member, which is a layer in which fine particles of metal oxide surface-treated with a compound are dispersed and contained. General formula (1)

[Chemical 3] In the formula, R ₁ is an alkylene group having 1 to 6 carbon atoms, R _1
2 , R ₃ and R ₄ are hydrogen atoms or 1 to 4 carbon atoms
R ₅ represents a hydrogen atom or a methyl group.

The present invention will be described in detail below. The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a photoconductive layer and a protective layer on a conductive support.

In the protective layer of the electrophotographic photosensitive member, it is indispensable to control the resistance because of the charging property, the residual potential, the sensitivity and the like. Therefore, conventionally, a method of controlling the resistance by dispersing a metal oxide in the binder resin in the protective layer has been tried, but in the conventional electrophotographic photoreceptor, the dispersibility of the metal oxide fine particles is poor and a problem. Was becoming. Generally, when particles are dispersed in a protective layer, the particle size of the particles must be smaller than the wavelength of the incident light, that is, 0.3 μm or less, in order to prevent scattering of the incident light by the dispersed particles. Is. However, the present inventors have discovered that in order to prevent the formation of secondary particles due to the aggregation of the metal oxide fine particles in the resin after the dispersion, the average particle diameter of the metal oxide fine particles must be further reduced. . However, with the resins tried so far, the dispersibility of the fine particles was poor and the electrical resistivity of the protective layer fluctuated significantly depending on the environment, so that it could not be put to practical use.

However, in order to satisfy both the dispersibility and the environment resistance of the metal oxide fine particles, the metal oxide ultrafine particles are surface-treated with the silicon acrylate compound represented by the general formula (1). , A phosphazene curable monomer represented by the following general formula (2) which is a highly polar monomer.

[Chemical 4] (In the formula, R ₇ represents a hydrogen atom or a methyl group, R ₈ represents an alkyl group, an aryl group, an alkyl-substituted aryl group, an alkylamide group, an arylamide group or polyoxylene). By dispersing in a resin containing a resin, a synergistic effect of the both does not cause formation of secondary particles, and a coating liquid having good dispersibility that is stable over time is obtained, and further formed from this coating liquid. The protective layer was highly transparent, and a film having excellent environmental resistance could be obtained.

The silicon acrylate compound represented by the general formula (1) has an alkoxysilane structure and an acrylic structure in the molecule at the same time, and therefore, it exhibits a coupling reaction with the hydroxyl group on the surface of the metal oxide and is hydrophobic. The structure has excellent properties, and at the same time, the acrylic group reacts with the phosphazene resin, resulting in a structure having excellent binding properties and dispersibility.

Specific examples of the above compounds include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltrihydroxysilane and γ-acryloxypropylethoxysilane.

As the conductive metal oxide used in the present invention, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony, Ultrafine particles such as zirconium oxide can be used. These metal oxides are used alone or in combination of two or more. When two or more kinds are mixed, they may be in the form of solid solution or fusion. The average particle size of such metal oxides is 0.3 μm or less, preferably 0.1 μm or less.

The phosphazene resin used in the present invention is a resin obtained by curing and polymerizing the phosphazene curable monomer represented by the above general formula (2) with ultraviolet rays and heat, and is excellent in transparency, high hardness and abrasion resistance. ing. Further, the dispersibility of the conductive powder such as metal oxide is also excellent, so that the protective layer has a high mechanical strength and a highly transparent protective layer can be formed. The phosphazene resin may be used alone, or other acrylic resin, polyester, polycarbonate, polystyrene, cellulose, polyethylene, polypropylene, polyurethane, epoxy resin, silicone.
It may be mixed with commercially available resins such as vinyl chloride and polyvinyl chloride.

In the present invention, additives such as a coupling agent and an antioxidant may be added to the protective layer for the purpose of improving dispersibility, binding property and weather resistance. The protective layer is formed by applying and curing a solution in which a metal oxide is dispersed in the binder resin.

The photoconductive layer of the electrophotographic photosensitive member of the present invention is composed of a single layer type containing both a charge generating substance and a charge transporting substance,
Alternatively, it is a laminated type in which a charge generation layer and a charge transport layer are laminated on a conductive support. The laminated electrophotographic photosensitive member will be described below.

As the constitution of the laminated type photoconductive layer, one having a charge generating layer and a charge transporting layer laminated in this order on a conductive support, and the other having a charge transporting layer and a charge generating layer laminated in this order on the contrary. is there.

The conductive support may be any one as long as it has conductivity, for example, aluminum, copper,
Drum or sheet-shaped molding of metals or alloys such as chromium, nickel, zinc or stainless steel, laminating of metal foil such as aluminum or copper on plastic film, aluminum, indium oxide, tin oxide, etc. Examples thereof include those vapor-deposited on a plastic film, and metals, plastics, papers and the like having a conductive layer provided by coating a conductive substance alone or with a binder resin.

The charge transport layer comprises a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene or phenanthrene in the main chain or side chain, indol, carbazol.
It is formed by using a coating liquid prepared by dissolving a nitrogen-containing ring compound such as diol, oxadiazol, or pyrazoline, a charge transporting substance such as a hydrazone compound, or a styryl compound in a resin having a film-forming property. Examples of the resin having such a film-forming property include polyester, polycarbonate, polystyrene, and polymethacrylic acid ester. The thickness of the charge transport layer is 5 to 40 μm, preferably 10 to 30 μm.

The charge generating layer contains a charge generating substance such as azo pigments such as sudan red and diamble, quinone pigments such as pyrene quinone and anthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, and phthalocyanine pigments. It is formed by dispersing it in a binder resin such as polyvinyl butyral, polystyrene, polyvinyl acetate, or acrylic resin and coating the dispersion, or by vacuum-depositing the pigment. The thickness of the charge generation layer is 5 μm or less, preferably 0.05 to 3 μm.

In the present invention, an undercoat layer having a barrier function and an adhesive function can be provided between the conductive layer and the photosensitive layer. The undercoat layer is casein, polyvinyl alcohol,
Nitrocellulose, ethylene-acrylic acid copolymer,
It can be formed from alcohol-soluble amide, polyurethane, gelatin or the like. A suitable film thickness is 0.1 to 3 μm.

As described above, the electrophotographic photoreceptor of the present invention has a protective layer in which metal oxide fine particles surface-treated with a silicon acrylate compound are dispersed in a resin containing a phosphazene resin on the photosensitive layer. The electrophotographic photosensitive member. Thereby, in the present invention, it was possible to form a uniform protective layer having high hardness and good dispersibility of the metal oxide fine particles. As a result, it has become possible to provide an electrophotographic photoreceptor having no image defects such as unevenness, fog, and black spots, extremely high abrasion resistance and environment resistance, and excellent electrophotographic characteristics.

The electrophotographic photosensitive member of the present invention can be applied to general electrophotographic apparatus such as a copying machine, a laser printer, an LED printer, a liquid crystal shutter type printer, and the like. It can be widely applied to devices such as recording, light printing, plate making, and facsimile.

The present invention also comprises an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention.

The present invention also comprises an electrophotographic apparatus equipped with the electrophotographic photosensitive member of the present invention and a facsimile having a receiving means for receiving image information from a remote terminal.

Next, an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member of the present invention will be described. Figure 1
The schematic structure of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention is shown in FIG. In the figure, reference numeral 1 denotes a drum type photosensitive member as an image bearing member, which is rotationally driven around a shaft 1a in a direction of an arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged at its peripheral surface by a charging unit 2 at a predetermined positive or negative potential in the course of its rotation, and then at an exposure unit 3 an optical image exposure L (slit exposure Laser
Beam scanning exposure). As a result, electrostatic latent images corresponding to the exposed image are sequentially formed on the peripheral surface of the photoconductor. The electrostatic latent image is then toner-developed by the developing means 4, and the toner-developed image is rotated by the transfer means 5 from a paper feeding portion (not shown) between the photosensitive body 1 and the transfer means 5. Then, the image is sequentially transferred onto the surface of the transfer material P that is fed in synchronization with the above. The transfer material P which has received the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 where it is subjected to image fixing and printed out as a copy (copy). The surface of the photoreceptor 1 after the image transfer is transferred by the cleaning means 6 to the toner after transfer.
Is removed, the surface is cleaned, the charge is removed by the pre-exposure means 7, and the surface is repeatedly used for image formation. Photoconductor 1
A corona charging device is generally widely used as the uniform charging means 2. Also, as the transfer device 5, corona transfer means is generally widely used. As an electrophotographic apparatus, a plurality of constituent elements such as the photoconductor, the developing unit, and the cleaning unit described above are integrally combined as an apparatus unit, and the unit is detachably attached to the apparatus main body. It may be configured. For example, the photoconductor 1 and the cleaning means 6 may be integrated into one device unit, and the device body may be detachably configured by using guide means such as a rail. At this time, the above-mentioned apparatus unit may be configured with a charging means and / or a developing means. In addition, the light image exposure L is used for an electrophotographic apparatus such as a copying machine or a printer.
When used as a light source, the reflected light or transmitted light from the original is used, or when the original is read and converted into a signal, this signal is used to scan the laser beam, drive the light emitting diode array, or liquid crystal shutter. -It is performed by driving the array or the like. Further, when used as a printer of a facsimile, the light image exposure L becomes an exposure for printing the reception data.

FIG. 2 is a block diagram showing an example of this case. The controller 10 controls the image reading unit 9 and the printer 18. The entire controller 10 is C
It is controlled by the PU 16. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 12. The data received from the partner station is sent to the printer 18 through the receiving circuit 11. Predetermined image data is stored in the image memory. The printer controller 17 controls the printer 18. 13 is a telephone. Line 14
The image (image information from the remote terminal connected via the line) received from the demodulator is demodulated by the receiving circuit 11, and then the CPU 16 performs signal processing of the image information and sequentially stores it in the image memory 15. . When at least one page of image is stored in the memory 15, the image of that page is stored. The CPU 16 reads out one page of image information from the memory 15 and sends the one page of image information signaled to the printer controller 17. Upon receiving the image information of one page from the CPU 16, the printer controller 17 controls the printer 18 to record the image information of the page. The CPU 16 is a printer
While recording by 18, the next page is being received.
The image is received and recorded as described above.

[0026]

【Example】

Example 1 On an aluminum cylinder (φ30 mm × 260 mm), an alcohol-soluble polyamide (trade name: Amilan CM) was used.
-8000, Toray Co., Ltd. 10 parts, methoxymethylated 6 nylon (trade name resin Tefin EF-30T, Teikoku Kagaku Co., Ltd.) 30 parts, methanol 150 parts, butanol 1
The preparation liquid dissolved in 50 parts of mixed solvent is applied by dip coating,
It was dried at 0 ° C. for 10 minutes to form an undercoat layer having a film thickness of 1 μm.

Next, 4 parts of a disazo pigment having the following structural formula,

[Chemical 5] 2 parts of butyral resin (trade name: S-REC BL-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts of cyclohexanone were dispersed in a sand mill for 48 hours, and then 100 parts of tetrahydrofuran was added to the coating liquid for the charge generation layer. Was prepared.
This coating solution is applied by dip coating on the undercoat layer at 80 ° C.
After drying for 5 minutes, a charge generation layer having a thickness of 0.15 μm was formed.

Next, 10 parts of a styryl compound having the following structural formula

[Chemical 6] And polycarbonate (trade name Yupiron Z-20
0, Mitsubishi Gas Chemical Co., Ltd.) 10 parts dichloromethane 2
It is dissolved in a mixed solvent of 0 part and 60 parts of chlorobenzene, and this solution is applied onto the charge generation layer by dip coating, and the solution is mixed at 120 ° C. for 6 minutes.
It was dried for 0 minutes to form a charge transport layer having a film thickness of 18 μm.

Next, 100 parts of antimony-containing tin oxide fine particles (trade name T-1, manufactured by Mitsubishi Materials Corp.) having an average particle diameter of 0.02 μm, γ-methacryloxypropyltrimethoxysilane (trade name KBM-503, 10 parts of Shin-Etsu Chemical Co., Ltd., 300 parts of ethanol with a stirrer 4
After stirring for 8 hours, the solution was filtered, washed, and dried to surface-treat the fine particles.

Next, 50 parts of a phosphazene curable monomer having the following structural formula,

[Chemical 7] 2-Methylthioxanthone 0.1 as a photopolymerization initiator
Parts, 40 parts of the fine particles subjected to the surface treatment, and toluene 30
0 parts were mixed and dispersed by a sand mill for 96 hours to prepare a coating liquid for protective layer. Using this coating solution, a film was formed on the charge transport layer by spray coating, dried, and then irradiated with ultraviolet rays from a high pressure mercury lamp at a light intensity of 8 mW / cm ² for 20 seconds to form a protective layer having a thickness of 5 μm. Then, an electrophotographic photosensitive member was formed.

The prepared electrophotographic photosensitive member was attached to a copying machine which repeats the process of charging-exposure-developing-transfer-cleaning in a cycle of 1.5 seconds, and electrophotographic characteristics were evaluated under normal temperature and normal humidity. The image was repeatedly printed under high temperature and high humidity of 35 ° C. and 85%, and the durability was repeated 100,000 times. As a result, as compared with the electrophotographic photoreceptor without a protective layer shown in Comparative Example 1 below,
The sensitivity and residual potential were the same, and an image without unevenness or black spots could be obtained. Moreover, a stable image could be maintained even when the image was repeatedly printed 100,000 times under high temperature and high humidity. The results are shown in Table 1. The dark portion potential is the surface potential of the electrophotographic photosensitive member when discharged at a corona discharge voltage +5 KV, and the larger the value, the better the charging ability.
The sensitivity is indicated by the amount of exposure required to reduce the surface potential from 700V to 200V.

Example 2 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the preparation liquid for the protective layer in Example 1 was changed as follows. Tin-containing indium oxide fine particles with an average particle size of 0.02 μm (trade name: ITO, Mitsubishi Materials Corporation)
100 parts, γ-methacryloxypropyltrimethoxysilane 10 parts, and ethanol 300 parts with a stirring device.
After stirring for a period of time, the solution was filtered, washed, and then dried to surface-treat the fine particles.

Next, 45 parts of a phosphazene curable monomer represented by the following structural formula,

[Chemical 8] 2-Methylthioxanthone 0.1 as a photopolymerization initiator
Parts, 45 parts of the surface-treated fine particles, 30 parts of toluene
0 parts were mixed and dispersed by a sand mill for 96 hours to prepare a coating liquid for protective layer.

Example 3 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the preparation liquid for the protective layer in Example 1 was changed as follows. Antimony-containing tin oxide fine particles with an average particle size of 0.02 μm (trade name T-1, Mitsubishi Materials Corporation)
100 parts, γ-achlorooxypropylethoxysilane 10 parts, and ethanol 300 parts were stirred for 60 hours with a stirrer, and then the solution was filtered, washed and dried to surface-treat the fine particles.

Next, 45 parts of a phosphazene curable monomer represented by the following structural formula,

[Chemical 9] 2-Methylthioxanthone 0.1 as a photopolymerization initiator
Parts, 45 parts of the surface-treated fine particles, 30 parts of toluene
0 parts were mixed and dispersed by a sand mill for 96 hours to prepare a coating liquid for protective layer.

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the protective layer was omitted, and the same evaluation was performed. As a result, the electrophotographic characteristics were good at the initial stage, but when the durability was increased, the charging ability was lowered, and good images could not be obtained from around 70,000 sheets.

Comparative Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the conductive fine particles used in the protective layer were not surface-treated.
Similar evaluation was performed. As a result, the electrophotographic characteristics at the initial stage were almost good, but image deletion occurred under high temperature and high humidity.

Comparative Example 3 Except that the resin used for the protective layer was replaced with polycarbonate.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 and evaluated in the same manner. As a result, black spots were generated in the initial image, and background stain was generated due to durability. In addition, the prepared liquid for the protective layer had poor dispersibility, and aggregation of fine particles was observed.

The results of Examples 1 to 3 and Comparative Examples 1 to 3 are shown below.

[Table 1]

[0040]

The electrophotographic photosensitive member of the present invention contains the metal oxide fine particles surface-treated with the silicon acrylate compound in the phosphazene resin.
The dispersibility of the metal oxide in the protective layer is good, and the electrophotographic characteristics are excellent. Further, since the protective layer has good wear resistance and environment resistance, by using the electrophotographic photoreceptor of the present invention,
It is possible to provide a stable image having a high image quality even after repeated durability, and the electrophotographic apparatus and the facsimile equipped with the electrophotographic photosensitive member also exhibit the above remarkable effects.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Drum type photoconductor as an image carrier (electrophotographic photoconductor of the present invention) 2 Corona charging device 3 Exposure part 4 Developing means 5 Transfer means 6 Cleaning means 7 Pre-exposure means 8 Image fixing means L Optical image exposure P Transfer material having received image transfer 9 Image reading unit 10 Controller 11 Receiver circuit 12 Transmitter circuit 13 Telephone 14 Line 15 Image memory 16 CPU 17 Printer controller 18 Printer-

Claims (4)

[Claims] 1. An electrophotographic photosensitive member having a photoconductive layer and a protective layer on a conductive support, wherein the protective layer is surface-treated with a phosphazene resin and a silicon acrylate compound represented by the following general formula (1). An electrophotographic photosensitive member comprising a layer in which metal oxide fine particles are dispersed and contained. [Chemical 1] In the formula, R ₁ is an alkylene group having 1 to 6 carbon atoms, R _1
2 , R ₃ and R ₄ are hydrogen atoms or 1 to 4 carbon atoms
R ₅ represents a hydrogen atom or a methyl group. 2. The electrophotographic photosensitive member according to claim 1, wherein the phosphazene resin is a resin obtained by polymerizing a compound represented by the following general formula (2). [Chemical 2] In the formula, R ₇ represents a hydrogen atom or a methyl group, and R ₈ represents an alkyl group, an aryl group, an alkyl-substituted aryl group, an alkylamido group, an arylamido group or polyoxylene. 3. An electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1. 4. A facsimile having an electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1 and means for receiving image information from a remote terminal. [0001]