JPH01243070A - Method for developing electrophotography - Google Patents

Abstract

PURPOSE:To obtain always superior picture images causing no frilling in a photosensitive layer for a long time by incorporating a specified polycarbonate into a surface layer of the photosensitive layer. CONSTITUTION:A photosensitive body is constituted of a polycarbonate contg. a structural unit expressed by the formula I and/or a structural unit expressed by the formula II, as primary recurrent units, in a surface layer, and a corona discharge member is allowed to contact with a drum base body having an exposed surface formed by removing the photosensitive body therefrom, and is rotated on the drum base body. In the formulas, each R3 and R4 is H atom, alkyl group, cycloalkyl group, or aryl group, wherein one of the R3 and R4 is bulky group; each R5-R12 is atom, halogen atom, alkyl group, or cycloalkyl group and the degree of polymn in 10-5,000; Z is an atomic group necessary for forming a carbocyclic ring or a heterocyclic ring and the degree of polymn. is 10-5,000. Thus, the photosensitive layer causes no frilling for a long time, and picture images having high quality are obtd. by development.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is an improvement in an electrophotographic development method for an image forming apparatus that visualizes an electrostatic latent image formed on a photoreceptor drum using a developer. Regarding.

[Prior art]

In an electrophotographic copying machine using the Carlson method, after the surface of a photoreceptor is charged, an electrostatic latent image is formed by exposure, the electrostatic latent image is developed with toner, and then the visible image is transferred to paper or the like. Transfer and fix. At the same time, the photoreceptor is subjected to removal of adhered toner, neutralization of static electricity, and surface cleaning, and is used repeatedly over a long period of time.

Therefore, as an electrophotographic photoreceptor, it not only has electrophotographic properties such as good charging characteristics and sensitivity, and low dark decay, but also has good printing durability, abrasion resistance, moisture resistance, etc. after repeated use. Physical properties, ozone generated during corona discharge,
It is also required to have good resistance to ultraviolet rays and the like during exposure (environmental resistance).

Conventionally, as electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide have been widely used.

On the other hand, the use of various organic photoconductive substances as materials for photosensitive layers of electrophotographic photoreceptors has been actively developed and researched in recent years.

For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-onylcarbazole and 2,4,7-trinitro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability. In order to improve these drawbacks, attempts have been made to develop organic photoreceptors with high sensitivity and durability by assigning the carrier generation function and carrier transport function to different substances in the photosensitive layer. ing. In such a so-called function-separated type electrophotographic photoreceptor, it is relatively easy to create an electrophotographic photoreceptor with arbitrary characteristics, since substances that exhibit each function can be selected from a wide range of materials. It is possible to create a

Using a low molecular weight organic compound as a carrier transport material,
Substances and polymer binders that generate arbitrary charges! Efforts have been made to obtain an electrophotographic photoreceptor having excellent electrophotographic properties and film strength by using these in combination.

As the polymer binder, polycarbonate is excellent in terms of charging characteristics, repeatability, and the like.

Examples of such polycarbonates include polycarbonates having the following structural units.

This polycarbonate has a structure in which two methyl groups are symmetrically bonded to the central carbon atom of bisphenol A. This polycarbonate is hereinafter referred to as BPA.

However, as a result of investigation, it was found that BPA has insufficient mechanical strength and has the disadvantage that a highly durable organic photoreceptor cannot be obtained.

On the other hand, a magnetic plan development method is often used as a means for developing an electrostatic latent image formed on a photoreceptor drum. Maintaining the accuracy within a predetermined range is a necessary requirement for stably obtaining images of average density and high quality.

One of the most commonly used methods for holding this DSD is the roller contact method. This roller contact method involves installing roller members with a radius larger than the radius of the developing sleeve by the dimension corresponding to the aforementioned DSD at both shaft ends of the developing sleeve so that they can rotate concentrically in one mountain. In this case, the above-mentioned DSD is secured by regulating the distance between the drum circumferential surface and the developing sleeve circumferential surface by pressing this roller member against the circumferential surface of the non-image area of the photosensitive drum.

Therefore, by manufacturing this roller member with high roundness and attaching it to the developing sleeve without eccentricity, the circumferential surface of the developing sleeve can accurately follow the circumferential surface of the drum, resulting in extremely high precision D.
SD can be retained.

Further, since the roller member itself rotates as a result of the rotation of the drum, it does not place a load on the photoreceptor + due to the rotation of the ram and does not affect its circumferential speed.

[Problem that the invention seeks to solve]

In order to avoid pressing the roller member mentioned above against the photosensitive layer of the photoreceptor, a method is used in which the photosensitive layer in the non-image area of the photoreceptor is removed using a solvent, etc. When this method is used with a body drum, the adhesion between the drum base and the photosensitive layer is not sufficient, so the photosensitive layer starts to gradually peel off from the end surface removed with the solvent, becoming powdery and entering the developing device and getting mixed into the developer. This damages the photosensitive layer in the image area during development, resulting in a loss of image quality.

Furthermore, since the photosensitive layer itself has internal stress, the solvent itself or its vapor during removal treatment tends to crack the photosensitive layer and cause it to peel off.

The purpose of the present invention is to solve this problem and improve it, thereby providing an electrophotographic developing method that does not cause peeling of the photosensitive layer over a long period of time, thereby consistently developing images of excellent quality. be.

[Means for solving problems]

The above purpose is to provide rotatable roller members at both shaft ends of a cylindrical developing sleeve, and to carry out development while bringing the roller members into contact with the circumferential surface of a drum having a photoreceptor on its outer circumferential surface. In the developing method carried out, the photoreceptor has a surface layer having the general formula (A
) and/or a structural unit represented by the general formula CB) as a main repeating unit (hereinafter referred to as BPZ), and the roller member has a photoreceptor that is attached to the photoreceptor. This is achieved by an electrophotographic developing method characterized by contacting and rotating the drum base exposed by removal.

[Structure of the invention]

The photoreceptor used in the electrophotographic developing method of the present invention has a BPZ-coated conductive photosensitive layer provided on a conductive drum, so this will be explained below.

The BPZ organic photoconductive photosensitive layer is usually composed of an organic photoconductive substance dispersed in a polycarbonate binder resin, and has a thickness of, for example, about 10 to 30 μm. This organic photoconductive photosensitive layer may have a single-layer structure, or may have a so-called functionally separated two-layer structure in which generation of carriers and transport thereof are shared by separate layers. In the case of a two-layer structure, the thickness of the generation layer responsible for generating carriers is, for example, 0605 to 5 μm1, and the thickness of the transport layer responsible for transporting carriers is, for example, 10 to 30 μm.

The generation layer and the transport layer each contain a binder resin of, for example, 20 to 90% by weight, preferably 30 to 70% by weight.
and 30 to 80% by weight, preferably 50 to 70% by weight.

The generation layer responsible for carrier generation is, for example, a monoazo dye,
Azo dyes such as bisazo dyes and trisazo dyes, perylene dyes such as perylene anhydride and perylene imide, indigo dyes such as indigo and thioindigo, polycyclic quinones such as anthraquinone, pyrenequinone, and furapanthrone, and quinacridone dyes. , bisbenzimidazole dyes, induthrone dyes, squarelillium dyes, metal phthalocyanine, phthalocyanine pigments such as metal-free phthalocyanine, pyrylium salt dyes, eutectic complexes formed from thiapyrylium salt dyes and polycarbonate, and various other known types. It can be formed by dissolving or dispersing a carrier generating substance together with a binder resin in a solvent and applying the solution. Among these, preferred is one obtained by dispersing a phthalocyanine-based, bisazo-based, or quinone-based carrier-generating substance in a binder made of a high molecular weight substance X of polycarbonate.

The transport layer responsible for transporting carriers is a compound having a polycyclic aromatic compound such as anthracene, pyrene, phenanthrene, cocomine in the main chain or side chain, or indole, carbazole, oxazole, inoxazole, thiazole, triazole, indazole. , compounds with a nitrogen-containing aromatic ring such as pyrazole, oxadiazole, and pyrazoline, and compounds with a triphenylamine skeleton, stilbene skeleton, and hydrazone skeleton are dissolved or dispersed in a solvent together with a binder resin. , can be formed by coating.

The binder resin is obtained by dispersing a carrier transporting substance such as styrylamine, hydrazone, carbazole, or hydrazine in a polycarbonate polymer binder described later.

BPZ used in the carrier generation layer and transport layer is a polycarbonate resin and has a structure in which the main repeating units are units represented by the above general formulas (A) and CB).

These carbonate resins are different from the conventionally used BPA.
The disadvantages of these polycarbonates have been improved, and at least one of the central carbon atoms of these polycarbonates has bulky (pulky) R3 or R4 bonded to it, or a ring formed by the above Z. , these R1
And/or R4 or Z effectively prevents the polycarbonate molecular chains from arranging in a specific direction. Therefore, the polycarbonate does not crystallize, causing the solution to gel or precipitate on the film surface during the formation of the photosensitive layer, and prevents characteristic deterioration such as a decrease in yield due to abnormal convexities and image defects due to poor cleaning. Can be done. These remarkable effects are even more pronounced when R3 and R2 in the general formula [A] are different from each other or are bonded asymmetrically. In the general formula CB), the ring formed by 2 directly contributes to the above remarkable effect. That is, in the present invention, by using the polycarbonate represented by the above general formula (A) or general formula [B] as the binder resin, the film has excellent physical properties and has excellent electrophotographic properties such as charge retention and sensitivity residual potential. It is possible to create an electrophotographic photoreceptor that exhibits excellent and stable characteristics with little fatigue deterioration even when subjected to repeated use.

Furthermore, when used as a photoreceptor, the surface of the photosensitive layer is less likely to be scratched even when rubbed by a magnetic brush or cleaning plate, and the photosensitive layer has less abrasion, and it has a high printing durability with no property defects such as poor cleaning. It is possible to create a photoreceptor.

In addition, the polycarbonate resin according to the present invention may optionally contain a cocondensation type polycarbonate containing other repeating units in addition to the repeating units of general formulas [A) and [B],
For example, the physical, chemical or electrical properties may be adjusted using a polycarbonate prepared by co-condensing 4,4'-dihydroxyphenyl-1,1-cyclohexane with a small amount of bisphenol A.

Furthermore, if necessary, other polymers may be mixed and used within a range that does not interfere with the effects. Examples of other polymers used in combination include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin,
Vinyl acetate resin, Epoquin resin, phenolic resin, polyurethane resin, polyester resin, alkyd resin, B
Polycarbonate resins other than PZ, silicone resins, addition polymer resins such as melamine resins, polyaddition resins, polycondensation resins, and copolymer resins containing two or more of the repeating units of these resins, such as chlorinated Examples include insulating resins such as vinyl-vinyl acetate copolymer resin and vinyl chloride-hinyl acetate-maleic anhydride copolymer resin, as well as polymeric organic semiconductors such as poly-N-vinylcarbazole.

The above-mentioned BPZ-based electroconductive photosensitive layer is formed as a coating film on the surface of a cylindrical photosensitive drum base made of aluminum, stainless steel, or the like by a method such as dip coating.

In this case, the dodim substrate is immersed from the axial direction of the cylinder into a dip coating container containing an organic solvent-based coating composition, but the entire length of the cylindrical portion is once completely immersed in order to equalize the thickness of the deposited coating. Thereafter, in the process of pulling up from the coating container, the solvent is evaporated, the coating film is solidified, and a -like photosensitive layer is formed on the entire circumferential surface.

Therefore, the circumferential surface of the photosensitive drum includes the same photosensitive layer in the non-image area as in the image area.

The photosensitive layer in the non-image area is locally peeled off and removed by dipping or coating with a solvent or mechanical friction in order to stabilize the pressure contact of the roller member mentioned above, but the BPZ organic photoconductive photosensitive layer is amorphous and under stress. Since it is relaxed throughout and has its own properties, it does not crack even if it is penetrated by solvent, and its adhesiveness is strong, so it has the characteristic that peeling does not extend to the image area.

- The toner constituting the two-component developer used in the strength wood invention is
It is made by dispersing toner components such as colorants in a binder resin, and various thermoplastic resins are used as the binder resin. Specific examples include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. , σ-methylene aliphatic monocarboxylic acid esters such as ethyl methacrylate, n-butyl methacrylate, lauryl methacrylate, and 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile; 2-vinylpyridine, 4- Vinyl pyridines such as vinyl pyridine; Vinyl ethers such as vinyl methyl ether ether; Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and methyl isopropenyl ketone; Unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; Polymers of monomers such as halides and halogen-based unsaturated hydrocarbons such as chloroprene, copolymers obtained by combining two or more of these monomers, and mixtures thereof; Non-vinyl condensation resins such as rosin-modified phenol-formalin resins, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins, or mixtures of these and the above-mentioned vinyl resins can be mentioned. Examples of the coloring agent include carbon black, nigrosine dye, aniline blue, calco oil blue yellow, ultramarine blue, methylene blue, rosebencal, phthalocyanine blue, and mixtures thereof. Toner components other than the colorant include a charge control agent, an anti-offset agent, a fluidity improver, and the like, and if necessary, fine magnetic powder may be contained.

Such a toner can be obtained by a conventionally known toner manufacturing method, and has an average particle size of 20 μF or less, particularly 8 to 12 μF.
μm toner is preferred.

The carrier constituting the two-component developer used in the present invention includes a core material and a monomer provided on the surface of the core material that preferably contains 50% by weight or more of a monomer represented by general formula III) or [■]. It is a particulate powder formed by overnight coating with a polymer of a polymer composition (hereinafter also referred to as "specific polymer") or a composition containing the polymer and other substances added as necessary. .

General formula [I] H2-C COOCH2CF2CF3 General formula [1) % formula %) t; where R represents hydrogen or a methyl group. Further, n and m represent integers from 1 to 9.

Examples of the polymer of the monomer represented by the general formula [■] or CI+) include, but are not limited to, those whose repeating units are represented by the following structural formula.

[Exemplary compounds]

COOCI (2CFs COOCH2CF2CF3 COOCHzCFzCFzCFzCF2HCOOCH2
CF2CF2CF2CF3CH.

1+CH2-C+ The above-mentioned specific polymer is obtained by using a monomer composition preferably containing 50% by weight or more of the monomer represented by the general formula (1) or (■), but it is not possible to use it. Other monomers that can be used include styrene, parachlorostyrene, α-
Methylstyrene and thonostyrenes Methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic Hn-
Examples include butyl, lauryl methacrylate, 2-ethylhexyl methacrylate, and monomethylene monocarboxylic acid esters.

The core material constituting the carrier must be made of a material that cannot form a magnetic brush, that is, a magnetic material. Examples of magnetic materials that can be used include ferrite, magnetite, iron, cobalt, Metals or alloys that exhibit ferromagnetism, such as nickel, or compounds containing these elements, or alloys that do not contain ferromagnetic elements but become ferromagnetic through appropriate heat treatment, such as manganese-copper-aluminum, Examples include a type of alloy called Heusler alloy containing manganese and copper such as manganese-copper-tin, chromium difluoride, and others.

The particle size of this core material is, for example, 30 to 200 μm, preferably 40 to 120 μm, and the shape is preferably spherical to improve fluidity.

The above carrier used in the present invention can be manufactured, for example, as follows. That is, the specific polymer or a composition containing the polymer is dissolved in a solvent such as acetone, a ketone such as methyl ethyl ketone, tetrahydrofuran, dioxane, or dimethyl sulfoquine to prepare a coating solution, and this coating solution is applied to the core material. Apply to the surface of the
A coating layer is thereby formed on the surface of the core material. In this application, a dipping method, a spray method, etc. can be used, but
Particularly suitable is the fluidization bending method.

This fluidized bed method uses a pressurized gas flow that rises in the fluidized bed device to lift and float the core material to an equilibrium height, and then the coating liquid is applied from above until the core material falls again. This is a method of spraying and coating each core material and repeating this process to form a coating film of a desired thickness. By this method, a uniform coating film can be formed on each core material.

The thickness of the coating layer is 0.2 to 5 μm, especially 0.5 to 2 μm.
The particle size of the carrier is preferably 3 μm, for example.
0-200 pm, preferably 40-120 pm
, particularly preferably from 50 to 75 μm. If the particle size of the carrier is less than 30 μm, the fluidity of the carrier is low and the ability to convey toner to the developing area is small, resulting in a decrease in image density, and furthermore, coating processing is difficult during the manufacture of the carrier. Therefore, it is difficult to obtain a carrier having such a small diameter and having a uniform coating layer. On the other hand, when the particle size of the carrier exceeds 200 μm, the surface area of the entire carrier particles per unit weight is small, so the ability to convey the toner to the development area is small, and image density tends to decrease.

Further, the carrier used in the present invention may contain additives such as a charge control agent and a fluidity improver, if necessary.

Next, the electrophotographic developing method used in the present invention will be explained.

FIG. 1 is a schematic sectional view of an electrophotographic copying machine to which the electrophotographic developing method of the present invention is applied.

The transparent original 'M' at the upper end and the original 2 placed on the tray L are held down by the original holding cover 3. When the copy key is pressed, the exposure lamp 5 of the light projecting unit 4 lights up and illuminates the original 2. , moves in the direction of the arrow together with the reflecting mirror uni-nod 6. The light irradiated onto the original 2 is transmitted to the image carrier through the reflection mirror 7 of the light projection unit 4, the reflection mirror unit 6, the imaging lens 8, and the reflection mirror 9, as shown by the dotted line. An electrostatic latent image is formed on the photosensitive drum 10 that is guided to the photosensitive drum 10 and charged by the charging electrode 11 . This electrostatic latent image is then developed into a toner image by a developing sleeve 13, which is a developer carrying member of a developing device 12, which is disposed close to the photosensitive drum IO. After the charge on the photoreceptor drum IO is removed by the pre-transfer charge removal lamp 14, the toner image is transferred by the transfer pole 18 onto the copy paper 17 that has been transported from the paper feed cassette 15 by the transport roller 16. . The copy paper 17 after transfer is transferred to the photosensitive drum IO by the separation pole 19.
After being separated from the fixing device 2 by the conveyor belt 20
Sent to 1, heated loaf 22,! : The toner image is fixed on the copy paper 17 by the pressure roller 23. After the fixing, the copy paper 17 is discharged onto a paper discharge tray 25 by a paper discharge roller 24. On the other hand, on the photoreceptor drum IO from which the copy paper 17 has been separated, the residual charge is removed by the removal electrode 26, and the f-1-ner remaining on the photoreceptor drum IO is cleaned by the cleaning device 27. The residual charge on the photoreceptor drum IO is removed by the charge removal lamp 28, and the photoreceptor drum IO is used for the next copying.

The developing device 12 will be explained in detail with reference to FIG.

The developing device 12 is located adjacent to the photoreceptor drum IO in a body 29.
It is placed on the horizontal wall 30 of. This developing device 12 includes a developer tank 31 and a toner replenishment tank 32, which are partitioned by a partition wall 34 provided in a cane puffer 33, and a communication hole 35 is formed in the bottom so that only the bottom can communicate with each other. 36 is a toner remaining amount detector. The toner in the toner replenishment tank 32 is supplied into the developer tank 31 by a toner replenishment roller 37 provided in the communication hole 35 at the bottom, and the developer consisting of toner and carrier is distributed between the first stirring member 38 and the second stirring member. The toner is conveyed to the developing sleeve 13 while being sequentially stirred by the roller 39. The shaft 13a of this developing sleeve 13
Abutting rollers 40 as roller members are rotatably provided at both ends of the body 2.
By being pressed against the photoreceptor drum IO by the pressing member 42 of the attachment/detachment device 41 attached to the photoreceptor 9, the developing sleeve 13 is placed parallel to the photoreceptor drum IO and close to the photoreceptor drum IO with a constant gap maintained. drum lO
The portion of the casing 33 facing the developing sleeve 13 has an opening 43.

FIG. 3 shows the relationship of the developing sleeve 13 to the photosensitive drum 10, taken along a cross section indicated by the arrow BB in FIG.

In the photosensitive drum IO, the photosensitive layer 10a on the circumferential surface of the drum is peeled off and removed at portions corresponding to non-image areas at both ends of the drum, exposing the base 10b of the drum.

The abutment roller 40 has a diameter that is twice as large as the outer diameter of the developing sleeve 13, plus the distance DSD between the drum surface and the peripheral surface of the developing sleeve 13, which should constitute a developing area, and the thickness of the photosensitive layer 10a. It has a correspondingly larger outer diameter, and is rotatably attached to both ends of a shaft 13a sandwiching the phenomenon sleeve 13 via a pair of left and right bearings.

Therefore, when the developing device 12 is pressed against the photosensitive drum IO side by the pressing member 42, the left and right abutting rollers 40 are pressed against the surface of the drum base 10b, and the peripheral surface of the developing sleeve 13 is pushed closer to the photosensitive layer 10a. A predetermined DSD is constituted by steps spaced apart in parallel.

The abutment roller 40 continues to rotate following the photosensitive drum 10 during the development operation with the photosensitive layer 10a on the drum surface removed and in pressure contact with the drum base 10b, so that the photosensitive layer 10a is protected from wear and tear. It is not subject to any effects that may cause damage, peeling, etc. Note that G in FIG. 3 is a gear for transmitting power from the copying machine main body to the developing sleeve 13, and is integrally fixed to the shaft 13a.

The developing sleeve 13 includes a rotating sleeve 46 made of a hollow non-magnetic material around the outer periphery of a magnet roller 45 in which a plurality of magnets 44 are arranged in the circumferential direction. The adsorbed developer is conveyed to the development area A by the rotating sleeve 46 while the spike length is regulated by the spike cutting member 47 . Then, the electrostatic latent image on the photoreceptor drum 10 is developed in the development area A to form a toner image. In addition, 48 is a paper feed guide member,
Reference numeral 14 denotes a static elimination lamp before transfer.

The developing device 12 described above is pressed against the photosensitive drum IO by the pressing member 42 of the attaching/detaching device 41 attached to the machine body 29, and when the developing device 12 is taken out from the machine body 29, the pressing member 42 is rotated clockwise. The pressure on the developing device I2 is released by moving the developing device I2, and the developing device I2 is moved on the horizontal wall 30 of the body 29 in a direction perpendicular to the axis of the photoreceptor drum IO, and is separated from the photoreceptor drum 10. This is done by pulling out the horizontal wall 30 of the body 29 toward the front in parallel with the axis of the drum IO. When attaching the developing device 12 to the machine body 29, perform the operation opposite to the above.

On the upper surface of the horizontal wall 30 of the body 29, as shown in FIG.
9 is provided protrudingly. On the other hand, a rail 50 that is parallel to the axis of the developing sleeve 13 is protruded from the lower surface of the bottom of the casing 33 of the developing device 12. Protrusions 52 that can be inserted into cutouts formed in the protrusion plate 49 of the body 29 are provided at approximately the center position and at a position close to the back surface. When the developing device 12 is attached to the body 29, the protrusion 52 of the casing 33 of the developing device 12 is inserted into the notch of the protruding plate 49 of the body 29, so that the developing device 12
Even if an attempt is made to pull out the developing sleeve 13 toward the front side along the axis of the developing sleeve 13, the protrusion 52 engages with the protrusion plate 49 and its movement is restricted, so that it cannot be pulled out.

When taking out the developing device 12 from the body 29, as described above, first move the developing device 12 on the horizontal wall 3o of the body 29 in a direction perpendicular to the axis of the photoreceptor drum 10, and then remove the developing device 12 from the body 29.
2 from the photoreceptor drum 10. Then, the protrusion 52 of the casing 33 of the developing device 12 touches the protrusion plate 4 of the body 29.
9 and then pull out the developing device 12 toward the front in parallel with the axis of the photoreceptor drum 10.
The developing device 12 can be taken out.

When attaching the developing device 12 to the body 29, perform the reverse operation to the above and attach the developing device 2 to the body 29, and the protrusion 52 of the casing 33 of the developing device 12 will fit into the notch of the protrusion plate 49 of the body 29. inserted into. In this way, when the developing device 12 is attached to the body 29, the developing device 12 cannot be pulled out along the axis of the developing roller 13, so when the developing device 12 is attached or removed, etc.
The surface of the photosensitive drum 10 is not damaged by the abutting roller 40 of the developing device 12.

〔Example〕

(Preparation of Photoreceptor) Parts by weight of hinyl chloride-vinyl acetate-maleic acid copolymer [Essle 7 MF-10JI manufactured by Tsukisui Kagaku Co., Ltd.] were dissolved in 100 parts by weight of methyl ethyl ketone to prepare an intermediate layer drop solution. An aluminum drum was immersed in this solution to form an intermediate layer having a thickness of 1 μm after drying.

Next, R, C, R, Dibromo Anceron "Monolite Red 2Yj l!fi part" was added to 50 parts by weight of 1.2 dichloromethane and dispersed in a ball mill. BPZ r manufactured by Gas Chemical Co., Ltd.
A carrier generation layer coating solution was prepared by dissolving and thoroughly mixing 5 parts by weight of Kneepilon Z-200J O, and an aluminum drum was immersed in this solution to form a carrier generation layer having a thickness of 1 μm after drying.

Next, 15 parts by weight of a styryl compound having the following structural formula as a carrier transport substance and 20 parts by weight of BPZrNipiron Z-300J manufactured by Mitsubishi Gas Chemical Co., Ltd. as a binder were dissolved in 100 parts by weight of 1.2 dichloromethane to prepare a carrier. A transport layer coating solution was prepared, and an aluminum drum was immersed in this solution to form a carrier transport layer having a dry film thickness of 19 μm.

Next, absorbent cotton was impregnated with dichloromethane to remove the photosensitive layer at both ends of the drum to obtain photoreceptor A of the present invention.

In addition, the binder of the carrier generation layer is made of Teijin Kasei WBP.
Photoreceptor B of the present invention was obtained in the same manner as photoreceptor A, except that Ar Panlite L-1250J was used, and the binder of the carrier transport layer was changed to BPZ [Kneepilon Z-200J manufactured by Mitsubishi Gas Chemical Co., Ltd.].

Next, the binder for the carrier generation layer was BP manufactured by Ondai Kasei Co., Ltd.
A photoreceptor C of the present invention was obtained in the same manner as photoreceptor A except that the A r panlite was changed to -11,300 J and the binder of the carrier transport layer was changed to BPZ "Kneepilon Z-200J" manufactured by Mitsubishi Gas Chemical Co., Ltd.

Furthermore, a photoreceptor of a comparative example was prepared in the same manner as photoreceptor A except that the substances shown in Table 1 were used as binders for the carrier generation layer and the carrier transport layer.

(Actual photo evaluation) Examples 1, 2.3 Photoreceptors A, B, and C of the present invention were used in a Konica Co., Ltd. copying machine r U-
Bix 1550" and conducted a live-action evaluation of 50,000 copies.

Comparative Example 1.2 Using photoreceptor D%E prepared for comparison, Example 1.
2. Similar to 3, live-action evaluation examples 1 and 2 of 50,000 copies.
Images with sufficient density without white streaks, black streaks, or fog were obtained with 3 and 50,000 copies. Further, no change was observed at both end portions of the photosensitive layer. The thickness reduction of the photosensitive layer in the area used for image formation is 1.0 to 1.0 after 50,000 copies.
It was very small at 2 μm.

On the other hand, a photoconductor using BPA on the surface of the photoconductor, E
In Comparative Examples 1 and 2, several white streaks were observed on the image after 10,000 copies. At this time, cracks are generated at both ends of the photosensitive layer, and the photosensitive layer peels off in flakes, and a portion of it is mixed into the developer, which partially reduces the amount of developer on the developing sleeve. It was found that this caused the white streaks. Furthermore, after 50,000 copies, in addition to white stripes, black stripes, fogging, and decreased density were observed on the image. At this time, both ends of the photosensitive layer were peeled off, and the film thickness of the photosensitive layer used for image formation was 3.8 to 4.
．． It was extremely large at 4 μm.

From the above, it is clear that the durability is improved by using the electrophotographic developing method of the present invention using BPZ on the surface of the photoreceptor.

〔Effect of the invention〕

In the present invention, by using a photoreceptor with high abrasion resistance and excellent strength, high quality images can be achieved over a long period of time, and as a result of the stabilization of the gap in the developing area, the density is always uniform and uniform. A useful electrophotographic developing method with extremely high performance that can develop images has now been provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronic copying machine to which the electrophotographic developing method of the present invention is applied, and FIGS. 2 and 3 are a sectional view and a diagram of the main parts of a developing device according to the developing method.

Claims (1)

[Scope of Claims] A rotatable roller member is provided at both shaft ends of a cylindrical developing sleeve, and the roller member is brought into contact with the circumferential surface of a drum having a photoreceptor provided on its outer circumferential surface. In the developing method of performing development, the photoreceptor contains a polycarbonate having a structural unit represented by the following general formula [A] and/or a structural unit represented by the following general formula [B] as a main repeating unit in the surface layer. An electrophotographic developing method, characterized in that the roller member contacts and rotates on a drum base exposed by removing the adhered photoreceptor. General formula [A] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, in the formula, R_3 and R_4 are hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted cycloalkyl groups, or substituted or unsubstituted aryl groups. At least one of R_3 and R_4 is a bulky group. R_5, R_6, R_7, R_8, R_9, R_1_0
, R_1_1, R_1_2 represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted cycloalkyl group, and the degree of polymerization is 10 to 5000,
Preferably it is 50-100. General formula [B] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, in the formula, R_5, R_6, R_7, R_8, R_9,
R_1_0, R_1_1, R_1_2 are the general formulas [
A] represents the same group as in A], Z represents an atomic group necessary to form a substituted or unsubstituted carbocycle or a substituted or unsubstituted heterocycle, and the degree of polymerization is 10 to 5000, preferably 5.
It is 0-1000.