JP2005234289A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which can prevent the dimensional precision from deteriorating when driving the photoreceptor and obtain high quality images without increasing the cost more than necessary. <P>SOLUTION: This electrophotographic photoreceptor has a photosensitive layer on a cylindrical resin base made by molding a conductive resin composite and a coupling shaft at least on one end of the cylindrical resin, and is formed in a way that the coupling shaft on the image forming device to drive this photoreceptor can engage with the coupling shaft of the above photoreceptor. The above cylindrical base and the coupling shaft are made by molding the same conductive resin composite. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member.

  An electrophotographic photoreceptor basically comprises a photosensitive layer for forming a latent image by exposure using charging and light, and a substrate on which the photosensitive layer is provided. Conventionally, a substrate obtained by processing aluminum into a cylindrical shape is generally used as a substrate used in an electrophotographic photosensitive member, and a photosensitive layer is formed on the surface, and further, the both ends are made of a resin material or the like. It has been generally used in a state where drive members such as gears and flanges are attached by bonding or caulking.

  On the other hand, the use of a resin as a material for a cylindrical substrate has also been studied. As an example of a substrate using this resin, for example, a substrate using a material obtained by dispersing conductive powder in polyphenylene sulfide resin (see Patent Documents 1 and 2), or using polyphthalamide as a resin material (Refer to Patent Document 3) and those using polyamide resin and conductive powder (refer to Patent Document 4). Or what formed the transparent conductive layer film | membrane etc. on the cylindrical resin base | substrate which does not contain conductive powder etc. is proposed (refer patent documents 5-7).

  Of these, those using a conductive material in which conductive powder is dispersed in a resin can be easily formed from the photosensitive layer and can be integrally formed with a driving part such as a gear. Of the same material, it is easy to obtain high dimensional accuracy compared to the method of attaching the drive member to the aluminum base by caulking by integrating the drive part with the drive part. Compared with the above, it is easy to obtain a relatively high rigidity by integrally molding, or driving due to the difference in linear expansion coefficient between the base aluminum and the resin used for the driving member against changes in storage environment, especially temperature Many studies have been made for reasons such as the fact that the separation phenomenon does not occur due to the peeling of the members and the structure is easy in the case of integral molding, which is advantageous in terms of cost.

  Here, when the conductive powder is dispersed in the resin and the substrate is molded, as the conductive powder to be used, for example, carbon black, graphite or metal powder is used.

  Among them, carbon black and graphite are frequently used because they are easy to handle and low in cost. A substrate obtained by molding a resin in which carbon black is dispersed has a black color due to the coloring effect of carbon black.

  Usually, when used as a substrate of a photoreceptor, a photosensitive layer is formed on the substrate to form an electrophotographic photoreceptor, and this is subjected to, for example, charging, exposure, latent image formation, development, transfer, etc. by a predetermined electrophotographic process. After fixing, it becomes an image.

  However, when a driving member such as a cylinder and a gear is integrated and the photosensitive member is driven through this gear or the like, the gear attached to the photosensitive member receives a driving force from the gear on the machine main body side. A part of the component concentrates on one part in contact, and a part of the component is applied in a direction perpendicular to the central axis of the photosensitive member to drive the photosensitive member and to bend the photosensitive member or to reduce the outer diameter roundness. To work.

  When the substrate of the photoconductor is made of, for example, aluminum, the rigidity is relatively high, so the influence on the dimensional accuracy such as bending and deformation of the photoconductor is small. Since the rigidity is lower than that of aluminum, the influence on the dimensional accuracy is large, and further, the influence on the image quality becomes large.

  In particular, since there is a tendency to improve the image quality such as increasing the image resolution as a recent trend, the influence of the dimensional accuracy on the image quality is increased, and it is not preferable that the dimensional accuracy deteriorates.

  Although it is possible to increase the rigidity by increasing the wall thickness, it increases the material cost by increasing the thickness, or the drying furnace when applying and drying the photoreceptor coating liquid due to the increase in the heat capacity due to the increase in thickness As a result, a higher capacity is required, which causes a cost increase.

  Accordingly, when a conductive resin composition is used for the photoreceptor substrate, a photoreceptor driving method that minimizes deterioration of the dimensional accuracy of the photoreceptor is desirable, and finding such a driving method is a problem. Met.

  On the other hand, as a means for driving the photosensitive member without using a gear-shaped member, for example, as disclosed in Patent Document 8, as a means for transmitting a driving force from the apparatus main body to the photosensitive member, a flange member having a coupling shaft A method has been proposed in which a coupling shaft is coupled to the end of the substrate, and a coupling shaft is provided on the drive shaft on the apparatus body side, and the driving force from the drive shaft is transmitted to the photoconductor via the coupling member. It is known as a driving method with excellent efficiency and driving accuracy.

  As described above, this driving method is excellent in accuracy as a driving method, but since it is generally performed in a form in which a flange member formed with a coupling shape is attached to an aluminum base, when the flange member is coupled, Items such as accuracy degradation and bond instability remained as they were.

JP 07-152194 A Japanese Patent Laid-Open No. 08-248659 Japanese Patent Laid-Open No. 08-032829 JP 2000-143978 A JP-A-10-123735 JP 2000-131864 A JP 2001-092166 A JP 08-270642 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrophotographic photosensitive member capable of preventing a reduction in dimensional accuracy when driving the photosensitive member and obtaining a high-quality image without an increase in cost more than necessary.

  In order to achieve the above object, according to the present invention, as a driving system, a coupling shaft is provided integrally with the photosensitive substrate at the end of the photosensitive member, and this coupling is paired on the main body side where the photosensitive member is installed. By providing couplings to be engaged and driving the photoconductor with a combination of these couplings, the above-mentioned problems can be solved to prevent a reduction in dimensional accuracy when driving the photoconductor, resulting in an increase in cost more than necessary. It has become possible to provide an electrophotographic photosensitive member capable of forming a high-quality image without any defects.

  That is, the present invention has a coupling shaft at least at one end of a cylindrical resin substrate of an electrophotographic photosensitive member having a photosensitive layer on a cylindrical resin substrate formed by molding a conductive resin composition. In a cylindrical base body in which a coupling shaft on the image forming apparatus main body side for driving the photosensitive body and a coupling shaft on the photosensitive body side can be engaged, the cylindrical base body and a coupling shaft attached to the cylindrical base body The portion is integrally molded with the same conductive resin composition.

  The resin used for the conductive substrate integrally formed with the coupling shaft member of the present invention is used by imparting conductivity by dispersing a conductive material in a commonly used resin. Any resin may be used as long as the resin can maintain its strength even when the conductive material is dispersed and does not cause a problem when it is molded.

  Examples of such resins include polyphenylene sulfide resins, cross-linked polyphenylene sulfide resins, various polyamide resins such as 6-nylon and 66-nylon, polycarbonate resins, polyethylene terephthalate resins, polybutylene terephthalate resins, phenol resins, polyacetal resins, Saturated polyester resins and the like are excellent in moldability and in terms of strength.

  The conductive powder added to these resins is generally easy to use and may be any powder that can be uniformly dispersed in the resin when mixed with the resin. For example, carbon black, graphite Metal powders such as aluminum, nickel and copper are used.

  Among these, carbon black, graphite and the like are preferably used as a conductive material because they are inexpensive and easy to handle.

  As addition amount of the electroconductive powder used for a base | substrate, 15 mass%-70 mass% of a resin part are preferable.

As the resistance value of the resin after the addition of the conductive powder, the volume resistivity is 1 × 10 ⁶ Ω · cm or less, preferably 1 × 10 ⁴ Ω · cm or less. The surface resistance value of the substrate is preferably 10 ⁶ Ω / cm or less.

  In the substrate of the present invention, a fibrous filler can be further added to the resin in which the conductive powder is dispersed for the purpose of ensuring the dimensional stability when the environment changes and increasing the strength. Examples of these fibrous additives include carbon whiskers and glass fibers. For the same purpose, inorganic powder fillers such as calcium carbonate and clay can be added.

  As a method for forming the conductive resin substrate of the present invention, for example, a method such as an injection molding method can be used. In the present invention, when the coupling part and the cylindrical base part are integrally formed, it is possible to form a gear for driving other parts than the photosensitive member. For example, by providing a gear portion separately from the coupling portion at the base end portion, the driving force transmitted from the apparatus main body to the base through the coupling portion is further applied to another member such as a developing sleeve through the gear. Can be used to communicate.

  Next, the photosensitive layer formed on the coupling-integrated resin substrate of the present invention will be described.

  The photosensitive layer in the present invention may be a laminated type composed of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material, or a single layer type containing the charge generation material and the charge transport material in the same layer. Although it is good, the laminated type is preferable.

  When the photosensitive layer is a single layer, the thickness of the photosensitive layer is preferably 5 to 100 μm, more preferably 10 to 60 μm. The single photosensitive layer preferably contains 10 to 70% by mass, more preferably 20 to 70% by mass of the charge generation material and the charge transport material.

  When the photosensitive layer has a laminated structure, the thickness of the charge generation layer is preferably 0.001 to 5 μm, more preferably 0.05 to 2 μm, and the thickness of the charge transport layer is preferably 1 to 40 μm, and more preferably 10 to 30 μm. The charge generation layer preferably contains 10 to 100 mass%, more preferably 40 to 100 mass% of the charge generation material. The charge transport layer preferably contains 20 to 80% by mass, more preferably 30 to 70% by mass of the charge transport material.

  The charge generation layer is composed of azo pigments such as monoazo, bisazo and trisazo: metal and metal-free phthalocyanine pigments; indigo pigments such as indigo and thioindigo; quinone pigments such as anthanthrone and pyrenequinone; perylene acid anhydride and perylene acid A solution in which a charge generating material such as a perylene pigment such as an imide; a squallium dye; a pyrylium; a thiapyrylium salt; and a triphenylmethane dye is dispersed in an appropriate binder resin is applied on the intermediate layer and dried. Can be formed.

  Examples of the binder resin for the charge generation layer include polyvinyl acetal resin, polycarbonate resin, polystyrene resin, polyester resin, polyacetate resin, acrylic resin, and cellulose resin. The thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm. Alternatively, the charge generation material may be vapor-deposited without using a binder resin.

  The charge transport layer is formed by applying a solution obtained by dissolving a charge transport material in an appropriate binder resin and drying the solution. Charge transport materials include electron transport materials and hole transport materials. Examples of the electron transporting substance include electron accepting substances such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, and tetracyanoquinodimethane, and high molecular weights thereof. The thing which was done is mentioned.

  Examples of the hole transporting substance include polycyclic aromatic compounds such as pyrene and anthracene; heterocyclic compounds such as carbazole, indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole, and triazole; p-diethylamino Hydrazone compounds such as benzaldehyde-N, N-diphenylhydrazone and N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole; α-phenyl-4′-N, N-diaminostilbene, 5- [4- ( Styryl-based compounds such as di-p-tolylamino) benzylidene] -5H-dibenzo [a, d] dicycloheptene; benzidine-based compounds; triarylamine-based compounds or those obtained by increasing the molecular weight thereof. Examples of the binder resin include a polycarbonate resin, a polyester resin, a polymethacrylic ester resin, and a polystyrene resin. The thickness of the charge transport layer is preferably 1 to 40 μm, particularly preferably 10 to 30 μm. Here, either the charge generation layer or the charge transport layer may be an upper layer or a lower layer.

  The single-layer type photosensitive layer can be formed by applying a solution obtained by dispersing and dissolving the above-described charge generating substance and charge transporting substance in an appropriate binder resin and drying it. The film thickness at this time is preferably 1 to 40 μm, and particularly preferably 10 to 30 μm.

  In the present invention, organic photoconductive polymers such as polyvinyl carbazole and polyvinyl anthracene, and inorganic materials such as selenium, selenium-tellurium and amorphous silicon can also be used as the photosensitive layer material.

  In the photoreceptor of the present invention, image defects are prevented by coating defects on the substrate surface between the substrate and the photosensitive layer, and deterioration of the photoreceptor sensitivity caused by mixing and coloring conductive powder in the substrate resin is prevented. In order to do so, a first intermediate layer can be provided.

  This intermediate layer is formed by dispersing inorganic conductive powder made of a metal oxide in a binder resin.

  Examples of the binder resin used for the intermediate layer provided on the substrate surface of the present invention include phenol resin, polyurethane resin, polyamide resin, polyimide resin, polyamideimide resin, polyamic acid resin, polyvinyl acetal resin, epoxy resin, acrylic resin melamine resin. Polyester resin or the like is used. These resins may be used alone or in combination of two or more.

  These resins have good adhesion to the substrate, good dispersibility of the conductive metal oxide powder dispersed in the resin, and good solvent resistance after film formation. Among these, phenol resin is particularly good.

  Examples of the conductive powder made of the metal oxide dispersed in the intermediate layer provided on the substrate include tin oxide containing antimony, tin oxide containing phosphorus, and tin oxide having a surface having oxygen deficiency by a reduction method. , Zinc oxide containing aluminum or gallium, indium oxide, and the like.

  In addition to these, the surface of the metal oxide particles having no electrical conductivity is coated with the above metal oxide film having electrical conductivity.

  Examples of the metal oxide particles having no electrical conductivity include barium sulfate, titanium oxide, calcium sulfate, calcium carbonate, aluminum oxide, barium carbonate, zinc oxide, magnesium oxide, and the like, for example, an oxide containing fluorine or antimony. It is used in combination of barium sulfate having a tin coating layer, titanium oxide having a tin oxide containing antimony oxide as a coating layer, or the like.

  These metal oxide powders are white and pale white, and when they are dispersed in a resin, the color is white. When a film is formed on a substrate, the film is also white or close to it. It becomes. For this reason, even when light is applied to the intermediate layer film, light is hardly absorbed and reflected, so that there is almost no decrease in the sensitivity of the photoreceptor as compared with the case where the intermediate layer is not provided and light is directly applied to the substrate. .

  Further, when it is desired to make the color tone of the intermediate layer closer to white or to increase the filling rate of the powder, for example, a titanium oxide powder without a coating layer, a barium sulfate powder or the like is used as a conductive powder. Can also be used in combination. The content of the metal oxide powder in the intermediate layer is preferably 1.0 to 90% by mass, more preferably 5.0 to 80% by mass with respect to the mass of the intermediate layer. When a metal oxide having no coating layer is added, the content is preferably 50% by mass or less of the entire metal oxide powder.

  The average particle diameter of the conductive metal oxide powder is preferably 0.05 to 2.0 μm, more preferably 0.07 to 1.0 μm.

  In the intermediate layer used in the photoreceptor of the present invention, when a laser beam having a single wavelength is used as an exposure light source, a spherical organic material is formed for the purpose of forming interference on the surface of the intermediate layer to prevent interference fringes. Resin powder can be contained.

  The spherical organic resin powder used can be used as long as it is dispersible in the intermediate layer and does not color the intermediate layer. For example, silicone resin, melamine resin, urea resin, acrylic resin can be used. , Styrene resin and the like, and silicone resin powder is particularly preferable.

  As the particle diameter of the spherical organic resin powder to be used, those having an average particle diameter of 1.0 μm to 6.0 μm are used, and preferably 1.0 μm to 4 μm.

  As content of spherical organic resin powder, it is 0.5-20 mass% with respect to the total mass of an intermediate | middle layer, Preferably it is 2-10 mass%. When the addition amount is less than 0.5%, the effect of preventing interference fringes is not sufficient, and when it exceeds 20%, an image defect occurs.

  The intermediate layer of the present invention is formed by dispersing conductive metal oxide powder in a binder resin solution and coating it on the surface of a conductive substrate, and drying and curing as necessary to form an intermediate layer To do.

  The film thickness of the intermediate layer of the present invention is preferably about 1 to 30 μm although it depends on the degree of defects on the surface of the substrate.

The volume resistivity of the intermediate layer of the present invention is preferably 10 ¹³ Ω · cm or less, particularly preferably 10 ¹² Ω · cm or less.

  A photosensitive layer is formed on this intermediate layer. In order to obtain the effects of the present invention more efficiently, a second intermediate layer (for example, a resin thin film) can be provided on the intermediate layer. The resin layer of the second intermediate layer is, for example, a water-soluble resin such as polyvinyl alcohol, polyvinyl methyl ether, polyacrylic acid, methyl cellulose, ethyl cellulose, polyglutamic acid, casein, starch, polyamide, polyimide, polyamideimide, polyamic acid, It can be formed by using a water-insoluble resin such as melamine, epoxy, polyurethane, or polyglutamic acid ester resin.

  Of these, polyamide resins are preferred in terms of coating properties, adhesion, solvent resistance, electrical barrier properties, resistance, and the like. Among the polyamide resins, low crystalline or non-crystalline copolymer nylon that can be applied in a solution state is more preferable. These second intermediate layers are dried by applying a solution obtained by dissolving the resin in water or an organic solvent onto the first intermediate layer, that is, the intermediate layer in which the conductive pigment of the present invention is dispersed in the resin. Is formed. The thickness of the second intermediate layer is preferably about 0.1 to 5 μm. If it is less than 0.1 μm, coating defects are likely to occur, and if it exceeds 5 μm, it may cause an increase in residual potential.

  In the case where the conductive intermediate layer is not provided, it is desirable that the surface of the substrate is subjected to a surface treatment for unevenness for the purpose of preventing the interference fringes. As a method of performing this surface processing, for example, a method such as direct blasting or liquid honing on the surface of the substrate, a method of transferring a roughened surface by pressing a roller having a roughened surface on the surface of the substrate, or the like, For example, there is a method of roughening the inside of a mold in advance when molding the substrate, and roughening the surface of the molded substrate by molding with this mold. As the surface roughness of the substrate surface in this case, the arithmetic average roughness Ra is preferably in the range of 0.2 to 2.0 μm.

  Even when the conductive first intermediate layer is provided or not provided, the second intermediate layer is preferably provided even when the substrate surface is roughened.

  Furthermore, in the present invention, a protective layer may be laminated on the photosensitive layer for the purpose of protecting the photosensitive layer.

  The protective layer is mainly composed of a resin. Examples of the material constituting the protective layer include polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenolic resin, acrylic resin, Silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin and the like can be mentioned. The thickness of the protective layer is preferably 0.05 to 15 μm, more preferably 1 to 10 μm.

  In the photoconductor having the coupling shaft of the present invention, the positioning accuracy of the photoconductor is high by the driving method, and the dimensional distortion generated in the photoconductor when rotating is also suppressed to a low level.

  Accordingly, the rigidity of the photosensitive member itself can be increased by the photosensitive member having the photosensitive layer on the substrate integrally formed with the coupling shaft according to the present invention, and a photosensitive member with low manufacturing cost can be obtained. The drive system in combination with the drive shaft on the main body side for engaging and driving the photoconductor enables high-precision positioning of the photoconductor during driving, and high-quality images can be obtained because the photoconductor is less deformed. Can be obtained.

  Next, the coupling shaft-integrated photoreceptor and the mechanism for driving the same in the present invention will be described with specific examples.

  A typical configuration according to the present invention for achieving the object of the present invention is a drive transmission mechanism for transmitting a rotational force by engaging a coupling convex shaft and a coupling concave shaft, wherein the coupling convex shaft is at least A convex portion having a shape having three positioning points, the coupling concave shaft being capable of inserting the convex portion of the coupling convex shaft, and a concave portion having a shape with which the positioning point of the convex portion can abut. And having a relationship of D1 <D0 <D2, where the circumscribed circle diameter of the convex shape is D0, the inscribed circle diameter of the concave shape is D1 and the circumscribed circle diameter is D2. It is said.

  In the above configuration, when the coupling convex shaft and the coupling concave shaft are engaged and driven, the positioning point of the convex portion comes into contact with the concave portion and the driving force is transmitted. At this time, if one of the coupling convex shaft or the coupling concave shaft is fixed in the rotational radial direction and the other is movable in the rotational radial direction, both members contact at the positioning point when the drive is applied. The position of both members is determined and the drive is transmitted. As a result, it is possible to prevent contact between the pieces of the coupling and backlash of positioning.

  In addition, since it is sufficient to fit the convex portion and the concave portion with a gap, it is possible to reduce the requirement for positioning accuracy of both members.

  As an example, for example, as shown in FIGS. 1 to 4, in the form of the photoreceptor having the coupling shaft of the present invention, the convex portion has a regular triangular prism shape, and the concave portion can be inserted with the triangular prism of the convex portion. It is formed in a shape that is hollowed out into a regular triangular prism of a large size.

  FIG. 1 is a perspective view of an example of a photoconductor having a convex coupling shaft, with three positioning points in the present invention, and FIG. 2 is a diagram for driving a photoconductor having a concave coupling shaft provided on the main body side. FIG. 3 is a perspective view of the photosensitive member viewed from the side surface and the end of the coupling convex shaft side.

  1 and 3, reference numeral 1 denotes a photosensitive body having a photosensitive layer formed thereon, 2 denotes a convex coupling portion, and 3 denotes a rotation guide hole when the photosensitive body is mounted on the apparatus main body or a cartridge and rotated. It is a support part to be inserted.

  In FIG. 2, 4 is a drive shaft portion, and 5 is a concave coupling portion for receiving a convex coupling shaft on the photoconductor side.

  FIG. 4 shows the positional relationship between the photosensitive member and the drive shaft on the main body side.

  Next, the mechanism of driving force transmission in the present invention will be described with reference to FIG.

  As shown in the figure, the convex portion has a shape of a regular triangular prism, and the concave portion is formed by hollowing out a regular triangular prism of a size that allows the convex portion to be inserted (similarity ratio is larger than 0.5). Less than 1.0). Here, as shown in FIG. 5 (b), the relation between the cross-sectional triangle of the convex portion and the cross-sectional triangle of the concave portion is that the diameter of the circumscribed circle R0 of the convex triangle is D0, and the inner diameter of the inscribed circle R1 of the concave triangle is When the diameter of the tangent circle is D1 and the diameter of the circumscribed circle R2 of the concave triangle is D2, it is configured to have a relationship of D1 <D0 <D2.

  Further, the coupling concave shaft 5 provided on the apparatus main body side is positioned so as to be movable in the rotational axis direction as described above, but not moved in the rotational radius direction. On the other hand, the coupling convex shaft 2 provided on the photosensitive member side is slightly movable in the rotational radius direction.

  A method for transmitting the driving force through the coupling mechanism from the image forming apparatus main body to the photosensitive member is as follows.

  In the above coupling configuration, when a photosensitive member having the convex coupling shaft 2 is mounted on the apparatus main body, the phase of the convex portion 2 and the concave portion 5 is matched (in this embodiment, since it is an equilateral triangle, every 120 ° When the two phases match each other, the two engage each other, and the rotational force is transmitted from the apparatus main body side to the photosensitive member side. In this coupling engagement, when the convex part enters the concave part, as shown in FIG. 5A, there is a certain difference between the sizes of the triangles, and the convex part smoothly enters with a gap. Accordingly, the positioning accuracy of the coupling convex shaft 2 and the coupling concave shaft 5 is sufficient to leave some clearance.

  Then, when the coupling concave shaft 5 rotates with the convex portion entering the concave portion, as shown in FIG. 5B, the three ridge lines of the triangular prism of the convex portion come into contact with the inner surface of the concave portion and the driving force is increased. Although it is transmitted to the coupling convex shaft 2, there is only one position where the three ridge lines contact the concave portion as described above when the coupling convex shaft 2 does not move in the rotational radius direction. For this reason, even if the positions of both coupling shafts are slightly shifted in a state where the convex portion enters the concave portion, the coupling convex shaft 2 moves in the rotational radial direction by the rotation of the coupling concave shaft 5, and finally In particular, the coupling convex shaft 2 is positioned when the three ridge lines contact the inner surface of the concave portion.

  By transmitting the driving force from the apparatus main body side to the photoconductor side by the coupling means having the above-described configuration, it is possible to moderately reduce the request for positional accuracy of coupling engagement. For this reason, the drive system can be easily designed and assembled, and the cost can be reduced.

  In addition, it is possible to reduce the contact and backlash of the engaging portion due to the error of the coupling member, and to provide the positioning of the photosensitive member via the driving shaft on the apparatus main body side, provided on the apparatus main body side. The positional accuracy of the photosensitive drum with respect to the optical system (not shown) is increased, and the image quality can be improved.

  Further, as an example of a configuration similar to this configuration, as shown in FIG. 6, the configuration of the photosensitive-member-side coupling convex shaft 6 is a shape in which a convex shaft of an equilateral triangle is twisted in the rotational direction. The concave portion of the coupling concave shaft 7 is also twisted in the rotational direction.

  As described above, the engagement portion is twisted in the rotational direction, so that the main body side drive shaft 4 with the coupling concave shaft 7 in the state where the convex shaft 6 and the concave shaft 7 are engaged with each other forms an image. When rotating in the direction, the coupling convex shaft 6 and the concave shaft 7 are attracted to each other, and the coupling between the two becomes more reliable.

  In the embodiment described above, the example in which the cross-sectional shapes of the convex portions 2 and 6 and the concave portions 5 and 7 constituting the engaging portion of the coupling means are regular triangles is shown, but the ridgeline of the triangular prism may be rounded. good. If it does in this way, breakage of the ridgeline in a convex part at the time of driving transmission by coupling can be prevented more effectively.

  In addition, the shape of the convex part and the concave part may not be a regular triangle in cross section as in the above-described embodiment, and if it is a polygonal column shape having three or more ridge lines (for example, a quadrangular column), positioning when engaged Since there are three or more points, drive transmission and positioning can be performed reliably, and the strength of the coupling shaft can be increased.

  Furthermore, the shape of the convex part and the concave part does not necessarily have to be similar, as long as the ridge line of the convex part contacts the inner surface of the concave part at three or more locations.

  Furthermore, if the taper is formed at the tip of the convex part, the entrance part of the concave part, or both, the convex part and the concave part can be smoothly connected.

  Further, in the embodiments described above, an example is shown in which the photosensitive member side coupling means is constituted by a convex shaft and the main body side coupling means is constituted by a concave shaft. However, the convex shaft and the concave shaft are formed on the photosensitive member side and the main body side. The same effect can be obtained even if it is replaced with.

  1 to 4 is actually integrally molded with a resin base having a triangular prism shape, and the first intermediate layer, the second intermediate layer, and the photosensitive layer are laminated thereon. When a photoconductor provided with a photosensitive layer was prepared and placed in a commercially available laser printer to produce an image, a uniform and good image with no unevenness or blur was obtained in a halftone image or a solid black image.

  The present invention is useful for an electrophotographic photosensitive member provided in an image forming apparatus such as a copying machine, a printer, or a facsimile that employs an electrophotographic system.

FIG. 3 is a perspective view of an example of a photoconductor having a convex coupling shaft among the photoconductors having a coupling shaft of the present invention. FIG. 2 is a perspective view of an example of an electrophotographic apparatus main body side drive shaft having a concave coupling shaft that engages with the photoconductor shown in FIG. 1. It is the figure which looked at the photoreceptor of FIG. 1 from the side surface and the convex coupling shaft end side. FIG. 5 is a diagram showing a state of engagement between a photoconductor having a coupling shaft and a main body side drive shaft. It is a model explanatory drawing of the state at the time of engaging the convex type and concave type coupling shaft of this invention, (a) is the state which engaged the coupling shaft convex part with the recessed part, (b) is from the drive shaft side. It is a figure which shows the state which is transmitting the driving force to the photoconductor side. FIG. 2 is a side view of a photoconductor having a coupling shaft whose convex shape is a twisted triangular prism and a view seen from the end of the coupling shaft. It is a figure which shows a mode that the photoconductor which has a coupling axis | shaft which the shape of the convex side twists the triangular prism, and the drive shaft which has this and engages with this and the drive shaft which has the concave shape axis | shaft of the twist shape.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor part of electrophotographic photoreceptor 2 Convex coupling shaft 3 Support part 4 Main body side drive shaft 5 Concave coupling shaft part 6 Convex coupling shaft 7 Twisted concave coupling shaft part

Claims (3)

An electrophotographic photosensitive member having a photosensitive layer on a cylindrical resin substrate formed by molding a conductive resin composition has a coupling shaft at at least one end of the cylindrical resin substrate for driving the electrophotographic photosensitive member. In the electrophotographic photosensitive member in which the coupling shaft on the image forming apparatus main body side and the coupling shaft on the photosensitive member side can be engaged,
An electrophotographic photoreceptor, wherein the cylindrical substrate and the coupling shaft are integrally formed of a conductive resin composition made of the same material.   2. The electrophotographic photosensitive member according to claim 1, wherein the coupling shaft on the photosensitive member side has a convex shaft shape, and the coupling shaft on the main body side driving shaft is a concave shaft.   When the convex shaft side has three or more positioning points, the circumscribed circle diameter of the convex shape is D0, the inscribed circle diameter of the concave shape is D1, and the circumscribed circle diameter of the concave shape portion is D2, D1 <D0 < 3. The electrophotographic photosensitive member according to claim 1, wherein the relationship of D2 is established.

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