JPH10307420A - Electrophotographic method and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such an electrophotographic method and device that a toner which causes contamination of the base, especially a normally electrified toner, hardly deposits on the electrophotographic photoreceptor and that contamination on the base in a finished image can be prevented. SOLUTION: This electrophotographic method includes a process to develop an electrostatic latent image formed on an electrophotographic photoreceptor by electrification and exposure with a developer containing a toner. The toner used in this method shows such properties that when an electrified toner by applying a developing bias voltage is deposited on a polycarbonate Z film without electrification and exposure, the charged energy distribution of the toner deposited on the polycarbonate Z film (the toner which causes contamination of the base) shows a normally electrified toner and a weakly electrified and/or reversely electrified toner, and the normally electrified toner has most of the charged energy distribution. Moreover, the outermost layer of the electrophotographic photoreceptor contains at least one kind selected from polyvinylbutyral, polymethacrylate, polyamide and cellulose acetate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic method and an electrophotographic apparatus, and more particularly to an electrophotographic method and an electrophotographic apparatus which are excellent in prevention of background contamination using a dry two-component or one-component developer. .

[0002]

2. Description of the Related Art A phenomenon in which toner adheres to a non-image portion of an electrophotographic photosensitive member, that is, a background potential portion (also simply referred to as a background portion) is called "background stain" or "fog". The causes of this phenomenon are roughly classified into two types. One of them is that the electrostatic characteristics of the electrophotographic photosensitive member are degraded, such as a decrease in the sensitivity of the photoreceptor or a rise in the residual potential, or the exposure amount is reduced due to contamination of an optical system in the electrophotographic device. When there is a problem in the body potential itself of the body, as a countermeasure, for example, a method of changing the latent image forming condition according to the measurement result of the photoconductor surface potential and controlling the background potential is known. . In the other case, the background potential of the photoconductor is normal, but there is a problem in the developing process. This case will be described below.

For example, in the case of a two-component developer, a large amount of toner sufficient for solid development once contacts (adheres) to the surface of the photoreceptor in the development nip, and the direction of the Coulomb force due to the development electric field. Depending on the size and size, whether the toner finally adheres to the photoreceptor side (developed) or returns to the carrier side (scavenged) is determined. If the developing electric field is constant, the direction and magnitude of the Coulomb force are determined by the charge amount of the toner particles, but the charge amount of the toner particles has a distribution, and the toner particles behave differently. Generally, a developing bias is applied to the developing nip for the purpose of reducing background stains, and a relatively large coulomb that is scavenged to the carrier side for many normally charged toners existing on the background in the developing nip. Since the force works, the background dirt is suppressed.

However, since a Coulomb force works in the direction of adhering to the photoconductor side to a small number of the oppositely charged toner present in the developer, the oppositely charged toner adheres to the background portion. In addition, since the weakly charged toner has a small Coulomb force toward the carrier, the toner tends to remain on the background without being scavenged by the carrier. Therefore, the background stain on the electrophotographic photosensitive member is caused mainly by the fact that the reversely charged toner and the weakly charged toner contained in the developer adhere to the background portion, which causes deterioration of the developer with time and mixing of the developer. It has been considered that the cause is an increase in reversely charged toner and weakly charged toner due to insufficient stirring.

Therefore, as a method for reducing the number of reversely charged toners or weakly charged toners in the developer, for example, JP-A-4-
Japanese Patent Laid-Open No. 110861 discloses a method for producing a developer in which the distribution area of an appropriately charged area in the toner particle charge amount distribution of the developer is about 70% or more of the total charge amount distribution area, and JP-A-4-1041. JP-A-777751 discloses a resin-coated carrier in which a resin coating containing conductive fine particles such as carbon black is formed on the surface of magnetic particles, and a surface layer portion rich in conductive fine particles is provided on the resin coating to form a positively chargeable carrier. It is disclosed that the distribution of the amount of charge with respect to the toner is made sharp. Further, JP-A-7-219275 discloses that the volume average particle size (DT) is 4.0 to 9.0 μm.
In the toner, the number average dispersed particle diameter (DCCA) of the charge control agent contained in the toner is (4 <DT / DCCA <90)
And the solubility of the charge control agent in water is 2.0
% Is disclosed.

As another means for reducing the number of oppositely charged toners or weakly charged toners in a developer, for example, Japanese Patent Application Laid-Open No. 3-91782 discloses a non-image area outside the area where recording or copying is originally performed. Japanese Patent Application Laid-Open No. Sho 63 (1988) discloses a method in which development is performed in a fogged state, and the deteriorated toner that has caused fogging is positively removed from the developer.
JP-A-265276 discloses that the photosensitive member is preliminarily rotated during the warming-up process, and the surface of the photoreceptor is charged to a potential having a polarity opposite to a potential for forming an electrostatic latent image during the preparatory rotation. Means for removing the developer by adsorbing it on the surface of the photoreceptor is disclosed. However, toners with a small particle size for high image quality and toners with a low softening point for low-energy fixing have been developed. Has not been sufficiently prevented.

[0007]

When the background stain when the developer having the toner as described above is used is examined, as the toner causing the background stain on the electrophotographic photosensitive member, a reversely charged toner or a weakly charged toner is used. Not only the normally charged toner (toner with a charge amount corresponding to the peak of the charge amount distribution of the toner in the developer) is also attached, but the normally charged toner is also attached as the main toner that causes scumming. It turns out that there are cases. Further, this normally charged toner has an overwhelmingly large number in the developer as compared with the oppositely charged toner or the weakly charged toner, and is transferred onto the transfer body in the transfer process, so that the background image is smeared. It was also found that it often stands out. Accordingly, an object of the present invention is to solve such a problem, and it is difficult for a toner that causes background contamination, particularly a normally charged toner that causes background contamination to adhere to the electrophotographic photosensitive member. An object of the present invention is to provide an electrophotographic method and an electrophotographic apparatus capable of preventing background stain on a printed image.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to develop a latent image formed on an electrophotographic photosensitive member by charging and exposure with a developer having a toner to form a toner image. In an electrophotographic method having a step of removing a toner remaining on a photoconductor after transferring an image onto a transfer body, as a toner, a polycarbonate Z film is charged by applying a developing bias without performing charging and exposure. When the toner is applied, the charge amount distribution of the toner (ground toner) adhered on the polycarbonate Z film includes a normally charged toner (A) and a weakly charged and / or reversely charged toner (B). A) uses a toner exhibiting a charge amount distribution occupying a major proportion, and the outermost layer of the electrophotographic photoreceptor has polyvinyl butyral, polymethacrylate, polyamide and It is achieved by an electrophotographic method, characterized in that it contains at least one selected from cellulose acetate. Further, an object of the present invention is to transfer at least a developing unit for developing an electrostatic latent image formed on an electrophotographic photosensitive member by charging and exposure with a developer having a toner to form a toner image. In an electrophotographic apparatus having a transfer unit for transferring onto a body and a cleaning unit for removing toner remaining on an electrophotographic photoreceptor after transfer, toner in a developer is charged and exposed on a polycarbonate Z film without being charged and exposed. When a toner is applied by applying a developing bias to the polycarbonate Z film so that only the developer comes into contact with the polycarbonate Z film, the charge amount distribution of the toner (ground toner) adhered on the polycarbonate Z film has a normal charge toner (A ) And a weakly charged and / or oppositely charged toner (B), and a charge amount distribution in which the normally charged toner (A) accounts for a major proportion. Ri, and the outermost layer of the electrophotographic photosensitive member polyvinyl butyral, polymethyl methacrylate, is achieved by an electrophotographic apparatus characterized in that it contains at least one selected from polyamides and cellulose acetate.

According to the present invention, the toner that causes background contamination, particularly the normally charged toner that causes background contamination, is difficult to adhere to the electrophotographic photosensitive member, and the background contamination in an image finally formed on copy paper or the like. Can be prevented.

[0010] The charge amount distribution of the toner (ground stain toner) attached on the polycarbonate Z film is normally charged toner (A).
The measurement of the fact that the normally-charged toner (A) exhibits a charge amount distribution occupying the main proportion, including the toner and the weakly-charged and / or oppositely-charged toner (B), can be performed as follows.

That is, first, the charge amount distribution of the toner in the developer (shown by a distribution diagram in which the horizontal axis is a value obtained by dividing the toner charge amount Q by the toner particle diameter d and the vertical axis is the number of toners). By measuring, the position of the horizontal axis of the peak of the normally charged toner (toner having a charge amount corresponding to the peak of the charge amount distribution of the toner in the developer) can be known, and then the toner attached on the polycarbonate Z film ( The charge amount distribution of the background toner is measured, and if the horizontal axis position of the main peak in the charge amount distribution of the background toner coincides with the horizontal axis position of the peak in the charge amount distribution of the toner in the developer, The charge amount distribution of the background smear toner shows a charge amount distribution in which the normally charged toner (A) and the weakly charged and / or oppositely charged toner (B) occupy the main proportion. .

As a method of measuring the charge amount distribution of the toner, for example, a method using a charge spectrum method or a method using a laser Doppler velocimeter is known, and any method is used to measure the charge amount distribution. However, here, a measuring method using a toner particle charge amount distribution measuring device (E-spart analyzer, manufactured by Hosokawa Micron) using a laser Doppler velocimeter is shown.

First, the distribution of the charge amount of the toner in the developer can be measured by an ordinary method. That is, the developer is held on the developer holding table serving as a magnet, the carrier and the toner are separated by an air gun (nitrogen gas), and the toner particles are suction-introduced to the measuring section, whereby the charge amount distribution of the toner can be obtained. . The measurement conditions at this time are as follows. Nitrogen gas blow pressure: 0.4 kg / cm ² G Blow time: 5 sec. Interval: 2 sec. Holder rotation speed: 320 rpm

Next, a method of measuring the distribution of the amount of charge of the toner (ground toner) adhered on the polycarbonate Z film will be described. First, as shown in FIG. 1, a coating 3 of polycarbonate Z is formed on a polyester film 2 having an aluminum vapor-deposited layer 1, and an aluminum foil 4 for conducting the aluminum vapor-deposited layer 1 and the aluminum tube to ground is provided. It is attached to the end of the polyester film and attached on the aluminum tube 5. This polycarbonate Z coating 3
Is mounted on, for example, a remodeled analog electrophotographic copying machine (FT-6500, manufactured by Ricoh Company), and a developing bias is applied without charging and exposing (-).
(150 V to -350 V), and the toner is adhered by the developing device. Next, the polyester film having the polycarbonate Z coating film to which the toner is attached in this manner is cut into strips, and the strip-shaped film 7 is placed on the developer holding table 6 of the E-SPART analyzer as shown in FIG. By sticking and rotating the developer holding table 6, nitrogen gas is blown from the air gun 8 to separate the toner from the coating film of the polycarbonate Z, and the separated toner particles are sucked and introduced into the measuring unit 9 so that the charge amount distribution of the toner is reduced. can get. The measurement conditions at this time are as follows. Nitrogen gas blow pressure: 0.6 to 0.7 kg / cm ² G blow time: 30 sec. Interval: 1 sec. Holding table rotation speed: 1000 to 1100 rpm

As a developer, the charge amount distribution of the toner (ground toner) adhered on the polycarbonate Z film includes a normally charged toner (A) and a weakly charged and / or reversely charged toner (B). A) When a developer having a toner having a charge amount distribution occupying the main proportion is used, the background stain is examined from the viewpoint of the electrophotographic photoreceptor, and the surface of the electrophotographic photoreceptor surface on which a toner image is formed It has been clarified that when a resin having a specific structure is used for the outermost layer of the photoreceptor, background contamination is prevented. That is, it has been clarified that background fouling is prevented when the outermost layer of the electrophotographic photosensitive member contains at least one selected from polyvinyl butyral, polymethacrylate, polyamide and cellulose acetate.

The electrophotographic photoreceptor in which the outermost layer in the present invention contains at least one selected from polyvinyl butyral, polymethacrylate, polyamide and cellulose acetate includes, for example, an inorganic photo-semiconductor layer such as selenium and amorphous silicon. An electrophotographic photoreceptor having a protective layer mainly containing these polymer compounds, an electrophotographic photoreceptor having an organic photoconductive material and a photosensitive layer containing these polymer compounds, or an organic photoconductive material And an electrophotographic photoreceptor in which a protective layer mainly containing these polymer compounds is provided on a photosensitive layer containing a resin.

Further, in the present invention, a release property may be imparted to the outermost layer surface of the electrophotographic photosensitive member in order to prevent background contamination. The method for imparting releasability to the surface of the outermost layer of the photoconductor is as follows: 1) adding a resin having a low surface energy to the outermost layer, for example, a resin having a fluorine-containing group or a silicon-containing group in its structure, 2) An additive for imparting water repellency and oil repellency to the outer layer, for example, an additive such as silicone oil and a surfactant is added. 3) JP-A-6-250413 and JP-A-6-95413 A material having high releasability, such as polytetrafluoroethylene, polyvinylidene fluoride, etc., is powdered and dispersed in the outermost layer; 4) a releasable substance, for example, saturated fatty acid metal Examples thereof include a method of applying a solid or liquid release agent such as a salt or a fluorine-based organic acid to the outermost surface of the photoreceptor.

In order to apply a release material to the surface of the outermost layer of the photoreceptor, JP-A-56-154778 and JP-A-57-154778
The device disclosed in Japanese Patent Laid-Open No. 58181, Japanese Patent Application Laid-Open No. 59-197068 or Japanese Patent Application Laid-Open No. 1-259392 may be used, or the device shown in FIG. 3 or 4 may be used. FIGS. 3 and 4 are cross-sectional views schematically showing an example of an apparatus for applying a release material to the surface of the outermost layer of the photoconductor, in which a material mainly containing zinc stearate as a release material is melted and cooled. This is an example using a solid lubricant that has been solidified.

In FIG. 3, by bringing the solid lubricant 12 into contact with the cleaning brush 11 in the cleaning device 10, the solid lubricant 12 is removed from the cleaning brush 11.
The particles of the lubricant are scraped off as fine particles of about 1 μm by the brush fibers, and the fine particles of the lubricant are carried on the brush fibers and adhere to the outermost layer surface of the electrophotographic photosensitive member 13. Thereafter, the fine particles of the lubricant are relatively firmly adhered to the outermost surface of the photoconductor by the contact pressure of the cleaning blade 14. In FIG. 3, a charger 16, a developing device 19 having a developing sleeve 17 and a stirring paddle 18, a transfer belt 20, a static elimination lamp 21 and a fixing device 22 are provided around the photoconductor 13.

Further, as shown in FIG. 4, the solid lubricant 12 may be brought into contact with the supply roller 15 and the supply roller 15 may be brought into contact with the cleaning brush 11. Further, in consideration of the development efficiency, it is desirable to minimize the amount of the releasable substance applied to the outermost layer surface of the photoreceptor. Therefore, the solid lubricant 12 and the supply roller 15 are cleaned by a contact / separation mechanism such as a solenoid. It is preferable to make the brush contact and separate from the brush.

The cleaning brush 11 includes:
For example, 360 denier / 2 with carbon-containing acrylic fiber
It is preferable to use a straight bristle brush having 4 filaments, 50,000 filaments / square inch, and a bristle length of about 5 mm. When a loop brush is used, the amount of solid lubricant shaving increases and the outermost layer of the photoreceptor is coated. It is not preferable because the amount becomes excessive. Depending on the photoreceptor linear speed, photoreceptor diameter, photoreceptor material, solid lubricant material, etc., the supply amount to the outermost surface of the photoreceptor is optimally adjusted according to the photoreceptor linear speed, the fiber thickness, etc. Just select it.

As the releasing agent, in addition to zinc stearate, other saturated fatty acid metal salts disclosed in JP-A-57-73774 and fluorine-based compounds disclosed in JP-A-57-90675. Organic acids and the like can be used, but zinc stearate is particularly preferred.

[0023]

The present invention will be described below in more detail with reference to examples.

Example 1 The charge amount distribution of the toner in the PPC developer type 1 (manufactured by Ricoh Co., Ltd.) was measured using the above-mentioned toner particle charge amount distribution measuring apparatus (E-Spart Analyzer, manufactured by Hosokawa Micron Corporation) under the above measurement conditions. FIG. 5 shows the result of the measurement by the usual measurement method. On the other hand, on a 75 μm-thick polyester film on which aluminum was deposited to a thickness of 1000 °, 0.5 μm of polyamide (CM8000, manufactured by Toray Industries, Inc.) was used.
Was coated with a 9% by weight tetrahydrofuran solution of polycarbonate Z (manufactured by Teijin Chemicals Ltd.) using a doctor blade, and dried to form a polycarbonate Z film. Next, the above film having a polycarbonate Z film is attached to the aluminum tube by bringing the aluminum vapor deposition film and the aluminum tube into conduction, and used as a modified machine of an analog type electrophotographic copying machine (FT-6500, manufactured by Ricoh Company). The developing device was operated on the polycarbonate Z film using PPC developer type 1 (manufactured by Ricoh Co., Ltd.) as a developer without charging and exposure. The aluminum vapor deposition film is grounded when the developing device is operated.
It was carried out with a developing bias of 0V applied. Also,
During the operation of the developing device, nothing was brought into contact with the polycarbonate Z film such as a cleaning blade. The charge amount distribution of the toner adhered on the polycarbonate Z film in this manner was measured by a toner particle charge amount distribution measuring apparatus (E-Spart Analyzer, manufactured by Hosokawa Micron Corporation) using the laser Doppler velocimeter. The charge amount distribution shown was obtained. 5 and 6
In the graph, the horizontal axis represents a value obtained by dividing the toner charge amount Q by the toner particle diameter d. In FIG. 5, the vertical axis indicates the number of toners, and in FIG. 6, the vertical axis indicates the number of toners corrected by the number of toners per unit area on the polycarbonate Z film. As is clear from FIGS. 5 and 6, the horizontal axis position of the main peak in the charge amount distribution of the toner (ground toner) adhered on the polycarbonate Z film is the horizontal axis of the peak in the charge amount distribution of the toner in the developer. It can be seen from FIG. 6 that the background smear toner is widely distributed from the oppositely charged area to the normally charged area, and the normally charged toner occupies the main proportion. That is, P
The toner in PC developer type 1 (manufactured by Ricoh Company) is
This is a toner having a charge amount distribution of the background toner that includes a normally charged toner (A) and a weakly charged and / or oppositely charged toner (B), and the normally charged toner (A) occupies a major proportion. Next, 0.4 part by weight of a bisazo pigment represented by the following structural formula (P) was added to butyral resin (S-REC BL-S,
Ball milling with 4 parts by weight of a 5% by weight tetrahydrofuran solution (manufactured by Sekisui Chemical Co., Ltd.) and 7.6 parts by weight of tetrahydrofuran, and after milling, adding tetrahydrofuran to dilute to 2% by weight to prepare a coating liquid for forming a charge generation layer. Then, the coating liquid was applied on a 75 μm-thick polyester film aluminum vapor-deposited film having a 1000-μm-thick aluminum vapor-deposited film by a doctor blade and dried to form a charge generation layer.

Embedded image Next, 6 parts by weight of the hole transporting material having the following structural formula (D) and 9 parts by weight of polyvinyl butyral (XYHL, manufactured by Union Carbide Co.) were dissolved in 67 parts by weight of tetrahydrofuran, and this was applied onto the charge generation layer and dried. 20
An electrophotographic photosensitive member was prepared by providing a charge transport layer having a thickness of μm.
The contact angle of the electrophotographic photoreceptor surface with water was measured using a contact angle meter (CA-X type, manufactured by Kyowa Interface Chemical Co., Ltd.) and found to be 82 °.

Embedded image The electrophotographic photosensitive member produced in this manner is attached to the aluminum tube by bringing the aluminum vapor deposition film and the aluminum tube into conduction, and used as a remodeling machine of an analog electrophotographic copying machine (FT-6500, manufactured by Ricoh Co., Ltd.). Equipped with a PPC developer type 1 (manufactured by Ricoh) as a developer, charging, exposing and developing by a usual method to form a toner image on an electrophotographic photoreceptor, and transferring the toner image to copy paper. Transfer was performed, and the presence or absence of background stain was visually evaluated for the image transferred to the copy paper. Table 1 shows the results. Further, using the electrophotographic photosensitive member manufactured as described above, toner (background toner) was adhered to the electrophotographic photosensitive member in the same manner as in the case of using the polycarbonate Z film. Stick part of the transparent tape on the electrophotographic photosensitive member to which the background toner is attached, and then slowly peel off the transparent tape (the transparent tape can have a part where the background toner is transferred and an untransferred part) Then, the peeled transparent tape was pasted on a blank sheet of paper, and the image densities of the toner transfer part and the untransferred part were measured with an automatic densitometer TC-6MC (manufactured by Tokyo Denshoku Gijutsu Center Co., Ltd.). The background ID level was evaluated by the tack ID value. Table 1 shows the results.
Shown in A smaller printer ID value indicates that the background toner does not adhere to the electrophotographic photosensitive member, that is, the background prevention level is superior. Further, the charge amount distribution of the background toner on the electrophotographic photoreceptor was measured in the same manner as the measurement of the charge amount distribution of the toner adhered on the polycarbonate Z film. As shown in FIG.
The amount of normally-charged toner adhered is mainly reduced compared to the above, and when an electrophotographic photoreceptor containing polyvinyl butyral is used in the outermost layer, normally-charged toner that causes scumming is less likely to adhere. It is shown that.

Example 2 In Example 1, polymethacrylate (Elvacite 2010, DuP) was used in place of polyvinyl butyral.
(manufactured by Ont Co., Ltd.), and an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a charge transport layer was formed using methyl ethyl ketone instead of tetrahydrofuran. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Further, using the electrophotographic photosensitive member, in the same manner as in Example 1, the image transferred on the copy paper was evaluated, and the background stain prevention level was evaluated by the PRINTAC ID value. Table 1 shows the results.

Example 3 A charge transport layer was formed in the same manner as in Example 1 except that a polyamide was used instead of polyvinyl butyral and butanol / ethanol (3/7) was used instead of tetrahydrofuran. An electrophotographic photosensitive member was manufactured. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Further, using the electrophotographic photosensitive member, in the same manner as in Example 1, the image transferred on the copy paper was evaluated, and the background stain prevention level was evaluated by the PRINTAC ID value. Table 1 shows the results.

Example 4 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that cellulose acetate (manufactured by Kanto Chemical Co., Inc.) was used instead of polyvinyl butyral to form the charge transport layer. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Using the electrophotographic photoreceptor, the image transferred to the copy sheet was evaluated in the same manner as in Example 1, and the background contamination prevention level was evaluated based on the printer ID value. Table 1 shows the results.

Example 5 After sticking the electrophotographic photosensitive member produced in Example 1 to an aluminum tube, an analog type electrophotographic copying machine FT-65 was used.
In the same manner as in Example 1 except that zinc stearate was applied to the surface of the photoreceptor and mounted on a remodeling machine of No. 00 (manufactured by Ricoh Co., Ltd.), the image transferred to the copy paper was evaluated, and the ground was evaluated based on the printer ID. The stain prevention level was evaluated. The contact angle of water on the surface of the electrophotographic photoreceptor coated with zinc stearate was measured in the same manner as in Example 1. Table 1 shows the results.

Example 6 After the electrophotographic photosensitive member produced in Example 2 was attached to an aluminum tube, an analog type electrophotographic copying machine FT-65 was used.
In the same manner as in Example 1 except that zinc stearate was applied to the surface of the photoreceptor and mounted on a remodeling machine of No. 00 (manufactured by Ricoh Co., Ltd.), the image transferred to the copy paper was evaluated, and the ground was evaluated based on the printer ID. The stain prevention level was evaluated. Further, the contact angle of water on the surface of the electrophotographic photosensitive member coated with zinc stearate was measured in the same manner as in Example 1. Table 1 shows the results.

Example 7 After attaching the electrophotographic photosensitive member produced in Example 3 to an aluminum tube, an analog type electrophotographic copying machine FT-65 was used.
No. 00 (manufactured by Ricoh Co., Ltd.) and the zinc stearate was applied to the surface of the photoconductor in the same manner as in Example 1 to evaluate the image transferred to the copy paper and to perform the ground printing based on the PRINTAC ID value. The stain prevention level was evaluated. The contact angle of water on the surface of the electrophotographic photoreceptor coated with zinc stearate was measured in the same manner as in Example 1. Table 1 shows the results.

Example 8 After the electrophotographic photosensitive member produced in Example 4 was attached to an aluminum tube, an analog type electrophotographic copying machine FT-65 was used.
No. 00 (manufactured by Ricoh Co., Ltd.) and the zinc stearate was applied to the surface of the photoconductor in the same manner as in Example 1 to evaluate the image transferred to the copy paper and to perform the ground printing based on the PRINTAC ID value. The stain prevention level was evaluated. The contact angle of water on the surface of the electrophotographic photoreceptor coated with zinc stearate was measured in the same manner as in Example 1. Table 1 shows the results.

Example 9 In place of the charge transport layer of Example 1, 6 parts by weight of the hole transport material of structural formula (D), 9 parts by weight of polyvinyl butyral (XYHL, Union Carbide Co.) and silicone oil (KF50, An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer was formed using a solution in which 0.009 parts by weight of Shin-Etsu Chemical Co., Ltd. was dissolved in 67 parts by weight of tetrahydrofuran. The contact angle of the surface of this electrophotographic photosensitive member with water was measured in the same manner as in Example 1. Further, using the electrophotographic photosensitive member, in the same manner as in Example 1, the image transferred on the copy paper was evaluated, and the background stain prevention level was evaluated by the PRINTAC ID value. Table 1 shows the results.

Example 10 In place of the charge transporting layer of Example 1, 6 parts by weight of a hole transporting material of the structural formula (D), polymethacrylate (Elvacit)
Example 1 except that the charge transport layer was formed using a solution of 9 parts by weight of e 2010, manufactured by Du Pont, and 0.009 parts by weight of silicone oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) in 67 parts by weight of methyl ethyl ketone. An electrophotographic photosensitive member was produced in the same manner as. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Using the electrophotographic photoreceptor, the image transferred to the copy sheet was evaluated in the same manner as in Example 1, and the background contamination prevention level was evaluated based on the printer ID value. Table 1 shows the results.

Example 11 In place of the charge transport layer of Example 1, 6 parts by weight of the hole transport material of the structural formula (D), 9 parts by weight of polyamide and silicon oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.009 parts by weight. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer was formed using a solution in which 67 parts by weight of butanol / ethanol (3/7) were dissolved. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Evaluation of an image transferred to a copy sheet using the electrophotographic photosensitive member in the same manner as in Example 1
And the background stain prevention level was evaluated by the PRINTAC ID value. Table 1 shows the results.

Example 12 In place of the charge transporting layer of Example 1, 6 parts by weight of the hole transporting material of the structural formula (D), 9 parts by weight of cellulose acetate (manufactured by Kanto Chemical Co.) and silicon oil (KF50, Shin-Etsu Chemical) Company)
An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the charge transport layer was formed using a solution in which 0.009 parts by weight of tetrahydrofuran was dissolved in 67 parts by weight of tetrahydrofuran. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Further, using the electrophotographic photosensitive member, in the same manner as in Example 1, the image transferred on the copy paper was evaluated, and the background stain prevention level was evaluated by the PRINTAC ID value. Table 1 shows the results.

Comparative Example 1 In Example 1, polyvinyl butyral (XYHL,
Polycarbonate Z instead of Union Carbide)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except for using. The contact angle of the electrophotographic photosensitive member surface with water was measured in the same manner as in Example 1. Using the electrophotographic photoreceptor, the image transferred to the copy sheet was evaluated in the same manner as in Example 1, and the background contamination prevention level was evaluated based on the printer ID value. Table 1 shows the results.
Shown in

Comparative Example 2 In Example 1, polyvinyl butyral (XYHL,
An oligomer having a styrene structure (Picolastic D125, Esso) in place of Union Carbide
An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that (Standard) was used. The contact angle of the surface of this electrophotographic photosensitive member with water was measured in the same manner as in Example 1. Using the electrophotographic photoreceptor, the image transferred to the copy sheet was evaluated in the same manner as in Example 1, and the background contamination prevention level was evaluated based on the printer ID value. Table 1 shows the results.

Reference Example 1 A polycarbonate Z was used in the same manner as in Example 1 except that PPC developer type 3300 (manufactured by Ricoh Company) was used as a developer.
The toner was deposited on the film, and the distribution of the charge amount of the toner was measured in the same manner as in Example 1. As a result, the charge including the normally charged toner, the weakly charged and the oppositely charged toner, and the weakly charged and the oppositely charged toner accounted for the main proportion. The quantity distribution was shown. An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that Polycarbonate Z was used instead of polyvinyl butyral (XYHL, manufactured by Union Carbide Co.), and the electrophotographic photosensitive member and PPC developer type were prepared. 3
In the same manner as in Example 1 except that 300 (manufactured by Ricoh Co., Ltd.) was used, the evaluation of the image transferred to the copy paper and the evaluation of the background contamination prevention level by the printer ID value were performed. Table 1 shows the results.

Reference Example 2 In Example 1, PPC developer type 3 was used as the developer.
In the same manner as in Example 1 except that 300 (manufactured by Ricoh Co., Ltd.) was used, the evaluation of the image transferred to the copy paper and the evaluation of the background contamination prevention level by the printer ID value were performed. Table 1 shows the results.

[0040]

[Table 1]

As is clear from Table 1, in the examples, good images were obtained without fog or background stain on the images transferred to the copy paper. In addition, the printable ID value in the example is also small, indicating an excellent background stain prevention level.

Further, as shown in Reference Examples 1 and 2, the charge amount distribution of the background soil toner includes a normally charged toner and a weakly charged and oppositely charged toner, and the weakly charged and oppositely charged toner occupies a major proportion. When a toner showing a quantity distribution is used, the outermost layer of the electrophotographic photoreceptor may or may not contain at least one selected from polyvinyl butyral, polymethacrylate, polyamide and cellulose acetate. Although there is almost no difference in the effect of preventing the background smear, the distribution of the amount of charge of the background smear toner includes the normally charged toner and the weakly charged and / or the oppositely charged toner, and the normally charged toner accounts for the main proportion. In the case of using a toner showing, the outermost layer of the electrophotographic photoreceptor is polyvinyl butyral, polymethacrylate, polyamide and Although it is possible to prevent the fog when containing at least one selected from acid cellulose, it is impossible to prevent scumming when not contain them.

[0043]

According to the present invention, toner that causes scumming on the electrophotographic photoreceptor, particularly normally charged toner, is unlikely to adhere, and scumming is finally prevented in an image formed on copy paper or the like. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a configuration of a polycarbonate Z film used for attaching a toner in the present invention.

FIG. 2 is an explanatory view schematically showing a configuration of an apparatus used for measuring a charge amount distribution of toner adhered on a polycarbonate Z film in the present invention.

FIG. 3 is a cross-sectional view schematically showing an example of an apparatus for applying a releasing material to the surface of the outermost layer of the photoconductor in the present invention.

FIG. 4 is a cross-sectional view schematically showing an example of an apparatus for applying a releasable substance to the outermost surface of the photoconductor in the present invention.

5 is a charge amount distribution chart obtained by measuring a charge amount distribution of toner in the developer used in Example 1 of the present invention. FIG.

FIG. 6 Polycarbonate Z in Example 1 of the present invention
FIG. 5 is a charge amount distribution diagram obtained by measuring a charge amount distribution of a toner attached on a film.

FIG. 7 shows polycarbonate Z in Example 1 of the present invention.
FIG. 9 is a charge amount distribution diagram obtained by measuring a charge amount distribution of toner adhered on an electrophotographic photosensitive member by a method similar to that applied on a film.

[Explanation of reference numerals] 1 aluminum vapor deposition layer 2 polyester film 3 coating of polycarbonate Z 4 aluminum foil 5 aluminum tube 6 developer holding base 7 strip-shaped film having a polycarbonate Z coating to which toner is attached 8 air gun 9 measuring part 10 Cleaning device 11 Cleaning brush 12 Solid lubricant 13 Electrophotographic photoreceptor 14 Cleaning blade 15 Supply roller 16 Charging device 17 Developing sleeve 18 Stirring paddle 19 Developing device 20 Transfer belt 21 Static erasing lamp 22 Fixing device

Claims (7)

[Claims] An electrostatic latent image formed on an electrophotographic photosensitive member by charging and exposure is developed with a developer having a toner to form a toner image, and after the toner image is transferred onto a transfer member, the photosensitive member is transferred. In the electrophotographic method having a step of removing the toner remaining on the polycarbonate Z film, the charged toner is applied by applying a developing bias without performing charging and exposure on the polycarbonate Z film. The charge amount distribution of the toner (ground stain toner) adhering to the toner includes a normally charged toner (A) and a weakly charged and / or reversely charged toner (B), and the normally charged toner (A) occupies a main proportion. Using the toner shown, and the outermost layer of the electrophotographic photosensitive member is at least selected from polyvinyl butyral, polymethacrylate, polyamide and cellulose acetate. An electrophotographic method, characterized in that the electrophotographic method further comprises one kind. 2. The electrophotographic method according to claim 1, wherein the outermost layer of the electrophotographic photosensitive member contains a releasing material. 3. The electrophotographic method according to claim 2, wherein the releasable substance is silicone oil. 4. The electrophotographic method according to claim 1, wherein a releasing material is provided on the outermost layer surface of the electrophotographic photosensitive member. 5. The electrophotographic method according to claim 4, wherein the releasable substance is zinc stearate. 6. A developing means for forming a toner image by developing at least an electrostatic latent image formed on an electrophotographic photosensitive member by charging and exposure with a developer having toner;
In an electrophotographic apparatus having a transfer unit that transfers a toner image onto a transfer member and a cleaning unit that removes toner remaining on the electrophotographic photosensitive member after the transfer, the toner in the developer is charged on the polycarbonate Z film and Polycarbonate Z by applying a developing bias without performing exposure
When the toner is attached so that only the developer comes into contact with the film, the charge amount distribution of the toner (background stain toner) attached on the polycarbonate Z film is weakly charged and / or reversely charged to that of the normally charged toner (A). The toner has a charge amount distribution that includes the toner (B) and the normally-charged toner (A) accounts for a major proportion, and the outermost layer of the electrophotographic photosensitive member is selected from polyvinyl butyral, polymethacrylate, polyamide and cellulose acetate. An electrophotographic apparatus comprising at least one kind. 7. The electrophotographic apparatus according to claim 6, further comprising means for applying a release material to the outermost layer surface of the electrophotographic photosensitive member.