JPH08179542A - Electrophotographic photoreceptor and process cartridge having same and electrophotographic apparatus - Google Patents

Abstract

PURPOSE: To prevent drop of surface resistance due to attachment of corona products and to obtain high image quality even under high humidity by dispersing fine metal oxide particles surface-coated with a specified fluorine-containing siloxane derivative into a protective layer. CONSTITUTION: The electrophotographic photoreceptor has on a conductive substrate with a photosensitive layer and the protective layer containing the fine metal oxide particles surface-coated with the F-containing siloxane derivative represented by the formula in which R is an alkyl, aryl, alkylated aryl, benzyl, polyoxyalkyl, or alkoxyl group substituted by >=1 F atoms for >=1 H atoms, thus permitting the fine metal oxide particles to be surface-coated with the F-containing siloxane derivative and to be dispersed into a binder resin, accordingly, secondary particles not to be formed, the obtained coating fluid to be stable against time lapse and good in dispersibility, and the protective layer formed by this coating fluid to have high transparency and to be superior in resistance to environments.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, particularly an electrophotographic photoreceptor having a protective layer.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is required to have required sensitivity, electrical 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 support, external electric and mechanical forces such as corona charging, toner development, transfer to paper and cleaning treatment are directly applied. In addition, durability against them is required. Specifically, it is required to have durability against abrasion and scratches on the surface due to rubbing, and deterioration of the surface due to ozone generated during corona charging. On the other hand, there is a problem that toner is adhered to the surface layer due to repeated toner development and cleaning, and to this end, improvement of the cleaning property of the surface layer is required.

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 proposed in JP-A-57-30843, there is proposed a protective layer in which a metal oxide is added as a conductive powder to control the resistance.

However, the conventionally used methods have problems in dispersibility and cohesiveness of the metal oxide fine particles in the binder resin, electrical conductivity when used in the protective layer, and transparency.
Non-uniformity of the surface of the protective layer, image defects due to unevenness, increase in residual potential due to repeated charging, and decrease in sensitivity were likely to occur.

In order to impart transparency and conductivity uniformity to the protective layer, it is more useful to disperse ultrafine particle powder (primary particle diameter: 0.1 μm or less). The body is normal fine particles (primary particle size 0.5 μm or more)
As described above, there is a problem that stable dispersion in the resin is difficult, secondary aggregation progresses over time, the dispersed particle size increases, and transparency and conductivity uniformity decrease. in causes a reduction in the surface resistance of the photosensitive member by ozone generated by repeatedly charging, corona products such as NO _X or the like adheres to the surface, the problem that the image flow occurs, satisfactory as yet protective layer No one showing electrophotographic properties has been obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to prevent electrophotographic deterioration of the surface resistance due to the adhesion of corona products which occur repeatedly in the electrophotographic process, and to maintain high quality image in high humidity. Providing a photoconductor, yet another object is to provide an electrophotographic photoconductor having excellent slidability and durability against abrasion of the surface due to rubbing and generation of scratches, and still another object. It is an object of the present invention to provide an electrophotographic photosensitive member that exhibits stable electrophotographic characteristics without accumulation of residual potential and deterioration of sensitivity in repeated electrophotographic processes.

[0007]

The present invention provides an electrophotographic photoreceptor having a photosensitive layer and a protective layer on a conductive support,
The protective layer is a layer in which fine particles of a metal oxide surface-treated with a fluorine-containing siloxane compound represented by the following general formula (1) are dispersed / contained, and the protective layer is composed of an electrophotographic photoreceptor. General formula (1)

Embedded image In the formula, R is an alkyl group in which one or more hydrogen atoms are substituted with a fluorine atom, an aryl group, an alkyl-substituted aryl group,
A benzyl group, a polyoxylene group or an alkoxyl group is shown.

The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a photosensitive 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 in view of the charging property, the residual potential and the sensitivity. Therefore, conventionally, a method of controlling the metal oxide by dispersing the metal oxide in the binder resin in the protective layer has been attempted, but in the conventional electrophotographic photoreceptor, the dispersibility of the metal oxide particles is It was a bad problem. 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 over time after dispersion, the average particle diameter of the metal oxide fine particles must be further reduced. . However, the resins tried so far have poor dispersibility of fine particles and the electrical resistivity of the protective layer fluctuates remarkably depending on the environment, so that it cannot be put to practical use.

The present inventor has conducted studies to satisfy both the dispersibility and environment resistance characteristics of the fine particles, and as a result, surface-treated the metal oxide fine particles with the fluorine-containing siloxane compound represented by the general formula (1). However, by dispersing in the binder resin, a secondary particle is not formed, and a coating liquid that is stable and has good dispersibility over time can be obtained, and the protective layer formed from this coating liquid has high transparency. Then, they have found that a film having excellent environment resistance can be obtained, and completed the present invention.

Specific examples of the fluorine-containing siloxane compound represented by the general formula (1) are shown in Tables 1 and 2.

[Table 1]

[Table 2]

The metal oxide fine particles used in the present invention include 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 oxide fine particles 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 ultrafine metal oxide particles is 0.3 μm or less, preferably 0.1 μm.
m or less.

Examples of the binder resin for the protective layer used in the present invention include acrylic resin, polyester and polycarbonate.
Resin, polystyrene, cellulose resin, polyethylene, polypropylene, polyurethane, epoxy resin, silicone
Resin, polyvinyl chloride, melamine resin and the like.

In the protective layer, dispersibility, binding property,
Additives such as coupling agents, antioxidants, and fluororesin fine particles may be added for the purpose of improving weather resistance.

The constitution of the photosensitive layer of the electrophotographic photosensitive member of the present invention is a single layer type containing both a charge generating substance and a charge transporting substance, or a laminated type in which a charge generating layer and a charge transporting layer are laminated on a conductive support. Is one of. Hereinafter, the laminated type photoreceptor will be described.

As the constitution of the laminated type photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order on a conductive support, or
On the contrary, the charge transport layer and the charge generation layer are laminated in this order.

The support used in the present invention may be any one having conductivity, and for example, a metal such as aluminum, copper, chromium, nickel, zinc, and stainless is molded into a drum shape or a sheet shape, aluminum or the like. Laminated metal foil such as copper on plastic film, vapor deposited aluminum, indium oxide, tin oxide, etc. on plastic film, metal on which conductive material is applied alone or with binder resin to form conductive layer , Plastic film, paper and the like.

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 is a charge generating substance such as azo pigments such as sudan red and diamble, quinone pigments such as pyrene quinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, and phthalocyanine pigments. Is dispersed in a binder resin such as polyvinyl butyral, polystyrene, polyvinyl acetate, and acrylic resin, and the dispersion is coated or the pigment is vacuum-deposited. 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
And nitrocellulose, ethylene-acrylic acid copolymer, alcohol-soluble amide, polyurethane, gelatin and the like. A suitable film thickness is 0.1-3 μm.

The electrophotographic photoreceptor of the present invention is used in a copying machine, a laser.
It can be generally applied to electrophotographic devices such as beam printers, LED printers, liquid crystal shutter-type printers, etc., and also widely used in devices such as displays, recording, light printing, plate making, and facsimiles to which electrophotographic technology is applied. Can be applied.

The present invention integrally supports the electrophotographic photosensitive member of the present invention and at least one means selected from the group consisting of charging means, developing means and cleaning means, and is attachable to and detachable from the main body of the electrophotographic apparatus. It is composed of a process cartridge characterized by being flexible.

Further, the present invention comprises an electrophotographic apparatus characterized by having the electrophotographic photosensitive member of the present invention, a charging means, an image exposing means, a developing means and a transferring means.

FIG. 1 shows a schematic structure of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 2 in a direction of an arrow at a predetermined peripheral speed. In the course of rotation of the photoconductor 1, the peripheral surface of the photoconductor 1 is uniformly charged to a predetermined positive or negative potential by a primary charging means 3, and then an image exposure means (non-exposure means) such as slit exposure or laser beam scanning exposure is used. Image exposure light 4 from the drawing is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then developed by the developing means 5.
The toner-developed toner image developed and developed by the transfer material 7 is fed from a sheet feeding unit (not shown) between the photoconductor 1 and the transfer unit 6 in synchronization with the rotation of the photoconductor 1. Then, the image is sequentially transferred by the transfer means 6. The transfer material 7 that has received the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 to undergo the image fixing, and is printed out as a copy (copy) to the outside of the apparatus. The surface of the photoreceptor 1 after the image transfer is cleaned by the cleaning means 9 after removal of the residual toner after transfer, and is further neutralized by the pre-exposure light 10 from the pre-exposure means (not shown). And then repeatedly used for image formation. The primary charging means 3 is a charging roller.
In the case of a contact charging means using a wire or the like, pre-exposure is not always necessary.

In the present invention, a plurality of constituent elements such as the photosensitive member 1, the primary charging means 3, the developing means 5 and the cleaning means 9 are integrally combined as a process cartridge. However, the process cartridge may be detachably attached to the main body of the electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging means 3, the developing means 5 and the cleaning means 9 is integrally supported with the photoconductor 1 to form a cartridge, and a guide means such as a rail 12 of the apparatus main body is used. The process cartridge 11 can be attached to and detached from the main body. Further, when the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 uses reflected light or transmitted light from a document, or a document is read by a sensor,
It is the light emitted by the signalization and the scanning of the laser beam, the driving of the LED array, the driving of the liquid crystal shutter array, etc., performed according to this signal.

On the other hand, when used as a printer for a facsimile, the image exposure light 4 becomes exposure light for printing the reception data. FIG. 2 is a block diagram showing an example of this case. The controller 14 controls the image reading unit 13 and the printer 22. The entire controller 14 is controlled by the CPU 20. The read data from the image reading unit 13 is transmitted to the partner station through the transmission circuit 16. The data received from the partner station is sent to the printer 22 through the receiving circuit 15. Predetermined image data is stored in the image memory. The printer controller 21 controls the printer 22. 17 is a telephone. The image received from the line 18 (image information from the remote terminal connected via the line) is demodulated by the receiving circuit 15, and then the image information is decoded by the CPU 20 and sequentially stored in the image memory 19. To be done. Then, when at least one page of image is stored in the image memory 19, the image of that page is recorded. CPU20
Reads one page of image information from the image memory 19 and sends the decoded one page of image information to the printer controller -21. Printer controller
When the printer 21 receives the image information of one page from the CPU 20, the printer 21 prints the image information of the page.
22 is controlled. The CPU 20 receives the next page during recording by the printer 22. In this way, the image is received and recorded.

[0028]

【Example】

Example 1 On an aluminum cylinder (φ30 mm × 260 mm), an alcohol-soluble polyamide (trade name: Amilan CM-80) was used.
00, manufactured by Toray Industries, Inc., 10 parts, methoxymethylated 6 nylon (trade name: Resin Resin EF-30T, Teikoku Kagaku Co., Ltd.)
Manufactured by dissolving 30 parts in a mixed solvent of 150 parts of methanol and 150 parts of butanol to prepare a dip coating solution,
It was dried at 90 ° 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,

Embedded image After 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, tetrahydrofuran 100 was added.
Parts were added to prepare a charge generation layer coating solution. This coating solution was applied onto the undercoat layer by dip coating and dried at 80 ° C. for 15 minutes to form a charge generation layer having a thickness of 0.15 μm.

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

[Chemical 4] And 10 parts of polycarbonate (trade name: Yupilon Z200, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 20 parts of dichloromethane.
It was dissolved in a mixed solvent of 60 parts of chlorobenzene, this solution was applied onto the charge generation layer by dip coating, and dried at 120 ° C. for 60 minutes to form a charge generation layer having a 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 size of 0.2 μm, 10 parts of the compound of the compound example (1) in Table 1 above, and toluene. After stirring 300 parts by a stirrer for 12 hours, the solution was filtered and washed, and then dried at 160 ° C. for 2 hours to perform surface treatment of the fine particles.

Next, 50 parts of a photocurable acrylic monomer (trade name Kayarad D-330, manufactured by Nippon Kayaku Co., Ltd.), 40 parts of the surface-treated fine particles and 150 parts of ethanol were mixed. The mixture was dispersed in a sand mill for 24 hours, and 5 parts of 2,4-diethylthioxanthone (trade name Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.) was added as a photopolymerization initiator to prepare a coating liquid for a protective layer. This coating solution is applied onto the charge transport layer by dip coating, dried and then exposed to 8 mW / cm with a high pressure mercury lamp.
^{It was} irradiated with ultraviolet rays at a light intensity of ² for 30 seconds to form a protective layer having a film thickness of 3 μm to prepare an electrophotographic photoreceptor.

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 0.75 seconds, and electrophotographic characteristics were obtained at room temperature and normal humidity of 22 ° C and 50%. Image evaluation under low temperature and low humidity of 10 ° C. and 15% and high temperature and high humidity of 35 ° C. and 85%, and repeated image durability of 50000 under normal temperature and normal humidity.
I went there. As a result, as compared with the 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, 500
A stable image could be maintained even when the image was repeatedly output 00 times. The results are shown in Tables 3 and 4.

Example 2 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the coating liquid for the protective layer was changed as follows. The results are shown in Tables 3 and 4.

100 parts of antimony-containing tin oxide fine particles having an average particle size of 0.02 μm (described above), 10 parts of the compound of the compound example (2) in Table 1 above, and 300 parts of toluene were stirred with a stirrer for 12 hours, and then the solution. Was filtered and washed, and then dried at 160 ° C. for 2 hours to surface-treat the fine particles.

Next, 50 parts of a photocurable acrylic monomer (trade name: Kayarad R-604, manufactured by Nippon Kayaku Co., Ltd.), 40 parts of the surface-treated fine particles and 150 parts of ethanol were mixed. The mixture was dispersed in a sand mill for 24 hours, and 5 parts of 2,4-diethylthioxanthone (described above) was added as a photopolymerization initiator to prepare a coating liquid for a protective layer.

Example 3 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the coating liquid for the protective layer was changed as follows. The results are shown in Tables 3 and 4.

Tin-containing indium oxide fine particles having an average particle diameter of 0.02 μm (trade name: ITO, Mitsubishi Materials Corp.)
100 parts, Compound 10 of Compound Example (7) in Table 1 above
Parts and 300 parts of toluene with a stirrer for 12 hours, the solution was filtered and washed, and then dried at 160 ° C. for 2 hours to perform surface treatment of the fine particles.

Next, 50 parts of a photocurable acrylic monomer (trade name Kayarad R-604, manufactured by Nippon Kayaku Co., Ltd.), 40 parts of the surface-treated fine particles and 150 parts of ethanol were mixed. The mixture was dispersed in a sand mill for 24 hours, and 5 parts of 2,4-diethylthioxanthone (described above) was added as a photopolymerization initiator to prepare a coating liquid for a protective layer.

Examples 4 to 7 In Example 1, the fluorine-containing siloxane-based compound was used as the compound examples (3), (4), (10) and (11), respectively.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that The results are shown in Tables 3 and 4.

Comparative Example 1 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the protective layer was not provided. As a result, as shown in Tables 2 and 3, the initial electrophotographic characteristics were good, but when the durability was increased, the chargeability was lowered, and good images could not be obtained from about 30,000 sheets.

Comparative Example 2 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the surface treatment of the antimony-containing tin oxide fine particles used in the protective layer was not performed. . As a result, under high temperature and high humidity, image deletion and image blurring due to durability occurred, and the dispersibility of the coating liquid for the protective layer was poor, and aggregation of fine particles was observed. Other evaluations are shown in Table 3 and Table 4.
Shown in

[0043]

[Table 3]

[Table 4]

[0044]

The electrophotographic photosensitive member of the present invention has no remarkable image defects such as unevenness, fog, and black spots, has very high abrasion resistance and environment resistance, and has excellent electrophotographic characteristics. .

[Brief description of drawings]

FIG. 1 is a process chart having an electrophotographic photoreceptor of the present invention.
It is a figure which shows schematic structure of the electrophotographic apparatus which has a triggle.

FIG. 2 is a diagram showing an example of a block of a facsimile having the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 1 Electrophotographic Photoreceptor of the Present Invention 2 Axis 3 Primary Charging Means 4 Image Exposure Light 5 Developing Means 6 Transfer Means 7 Transfer Material 8 Image Fixing Means 9 Cleaning Means 10 Pre-Exposure Light 11 Process Cartridge 12 Rails 13 Image reading unit 14 Controller 15 Receiver circuit 16 Transmitter circuit 17 Telephone 18 Line 19 Image memory 20 CPU 21 Printer-Controller 22 Printer-

Claims (3)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer and a protective layer on a conductive support, wherein the protective layer is a metal oxide surface-treated with a fluorine-containing siloxane compound represented by the following general formula (1). An electrophotographic photosensitive member, which is a layer in which fine particles are dispersed and contained. General formula (1) In the formula, R is an alkyl group in which one or more hydrogen atoms are substituted with a fluorine atom, an aryl group, an alkyl-substituted aryl group,
A benzyl group, a polyoxylene group or an alkoxyl group is shown. 2. The electrophotographic photosensitive member according to claim 1, and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported, and are detachably attached to the main body of the electrophotographic apparatus. A process cartridge characterized by the following. 3. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an image exposing unit, a developing unit and a cleaning unit. [0001]