JP5111010B2 - Electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge using the same, and an image forming apparatus such as a printer, a copying machine, a facsimile machine, and a complex machine of these.

  Electrophotographic technology is widely used and used in printers connected to facsimile machines and personal computers, but in recent years, digital recording technology has been applied not only to printers but also to ordinary copying machines, and development of digital copying machines. The demand has been on an increasing trend in the future.

  Such a digital copying machine is required to increase the life of the apparatus for the purpose of improving the image forming speed, improving the image quality, reducing the size, and reducing the environmental load from the viewpoint of efficient use of the office environment.

  In today's electrophotographic apparatus, in accordance with demands from the market, many color copiers, color printers, and the like are on the market, and colorization is progressing. By the way, a color electrophotographic apparatus is provided with a developing device of a plurality of colors around one photoconductor (image carrier), forms a color image on the photoconductor, and forms a color image by transferring the toner image. The so-called tandem is a so-called tandem that has a so-called revolver type and a developing device for each photoconductor, forms monochromatic images, arranges them side by side, and sequentially transfers the monochromatic images. Each type is widely used.

  Since the revolver type uses only one photoconductor, it is relatively advantageous to reduce the size of the apparatus, but it is disadvantageous to increase the speed because it requires image formation a plurality of times. On the other hand, the tandem type is large in size, but is advantageous for speeding up. In recent years, a color image forming apparatus is required to have a speed similar to that of a monochrome machine, and thus a tandem type image forming apparatus has been attracting attention.

  An example of a tandem type image forming apparatus is shown in FIG. In this apparatus, reference numeral 01 in the drawing denotes an image carrier (photosensitive member) that can be driven to rotate. First, the surface of the image carrier 01 is uniformly charged by the charging device 02. Next, the laser beam 03 is irradiated by the exposure optical system, the surface of the image carrier 01 is exposed to form an electrostatic latent image on the image carrier, and then the developer 05 in the developing unit 04 is applied to the image carrier 01. A visible image is formed on the image carrier 01 by moving to the surface. Next, at the contact portion between the intermediate transfer device 06 and the image carrier 01, the developer 05 on the surface of the image carrier 01 is intermediately transferred by a transfer roller 07 provided inside the intermediate transfer device 06 at the contact portion. Transfer to the surface of the transfer device 07. The transferred developer is transferred onto the paper at the secondary transfer unit 08 and then supplied to the fixing device 09 to fix the toner image on the paper. On the other hand, the developer 05 remaining on the surface of the image carrier 01 is removed by the cleaning blade 011 in the cleaning device 010 in preparation for the next image formation.

  The cleaning device 10 includes a device using a fur brush, a magnetic brush, or the like, and a device using a cleaning blade. However, the cleaning device 10 has a simple structure and is inexpensive, so that the residue adhered to the surface of the photosensitive member by the cleaning blade. Cleaning devices of the type that scrape off things are widely used.

  In order to obtain good image quality with this type of cleaning device 10, it is necessary to remove the transfer residual toner from the image carrier 01 with a cleaning blade 011. Therefore, in order to improve the toner blocking force of the cleaning blade 011, the cleaning blade 011 may be pressed against the image carrier 01 with as high a pressure as possible to increase the adhesion between the image carrier 01 and the cleaning blade 011. Many.

  Further, in order to improve the cleaning performance, the transfer residual toner staying in the vicinity of the contact portion between the cleaning blade 011 and the image carrier 01 is swept away, and therefore the friction force between the cleaning blade 011 and the image carrier 01 is used to clean the cleaning blade. It is known to activate the compression recovery behavior (stick slip) of 011. By pressing the cleaning blade 011 against the image carrier 01 with a high pressure, the stick-slip is accelerated and the cleaning property is improved. Further, although a rubber material is often used for the cleaning blade 011, stick-slip is accelerated and a cleaning property is improved by using a blade having high resilience as the rubber material of the blade. However, if the linear pressure at the contact portion between the cleaning blade 011 and the image carrier 01 is excessively increased, chatter noise is generated due to excessive vibration of the cleaning blade 011, or the contact point between the cleaning blade 011 and the image carrier 01. Noise may occur due to resonance. That is, a certain amount of stick-slip is necessary to maintain the cleaning property, but there is a conflicting effect that the blade will sound if it is too large.

  Conventionally, various methods have been proposed to reduce such abnormal noise. According to Patent Document 1, a charging member to which an oscillating voltage is applied to charge the photosensitive drum in contact with the photosensitive drum and a cleaning device having a cleaning blade for cleaning the photosensitive drum are provided, and the cleaning device absorbs vibration. It has been proposed to reduce the charging noise generated between the charging member and the photosensitive drum. However, the vibration of the blade holder itself cannot be suppressed only by the vibration absorbing portion of the cleaning device.

  According to Patent Document 2, it is stipulated that a plurality of cleaning blades of different materials are selectively used depending on the temperature around the cleaning. However, the use of a plurality of blades increases the cost, and the switching mechanism of the blade, the large size of the layout, etc. Inevitable.

  According to Patent Document 3, a vibration damping member for a leaf spring is provided on one surface of the cleaning blade to prevent noise. However, since the fulcrum of the cleaning blade is a spring member, vibrations when the image carrier rotates are picked up. Therefore, the contact state is not stable, and it is difficult to ensure a stable cleaning property.

In this way, attempts have been made to impart a vibration damping effect to the blade and suppress the vibration of the blade itself, but none of them has a sufficient effect. Therefore, a method for imparting a vibration damping effect to an image carrier that transmits vibration and resonates has been proposed.

  For example, according to Patent Document 4, in a photosensitive drum built in a process cartridge of an image forming apparatus, a metal cylindrical member, an elastic material that surrounds at least a part of the outer surface of the cylindrical member, and an outer surface of the cylindrical member are elastic. An anti-vibration material having a coating layer in close contact with the material is disposed in the drum cylinder so as to absorb the vibration of the photosensitive drum and reliably absorb the vibration generated when the photosensitive drum rotates. It has been proposed to increase the adhesiveness. However, the drum is partially deformed or bulged by press-fitting a vibration-proof material having a coating layer in which an elastic material is adhered to the outer surface of the cylindrical member into the drum cylinder. Problems such as bending will occur.

  According to Patent Document 5, in an electrophotographic photosensitive member having a photosensitive layer on a conductive cylindrical support having an outer diameter of 50 mm or less and having a vibration suppressing member inside the cylindrical support, It has been proposed that the cylindricity should be 0.03 mm or less to reduce vibration noise generated by the contact charging method and vibration noise of the cleaning blade, and to obtain a high-quality image without image unevenness. However, since the vibration suppression member having an outer diameter larger than the inner diameter of the support is reduced in diameter so as to be in close contact with the inner wall after being inserted into the cylindrical support, the cylindrical support is caused by the difference in the outer diameter between the support inner diameter and the vibration suppression member. The part which does not adhere to a body will arise. In addition, vibration noise may not be sufficiently suppressed due to variations in the inner diameter of the support and the outer diameter of the vibration suppressing member.

Japanese Patent Laid-Open No. 5-341701 JP-A-5-341699 JP-A-4-172486 JP 2001-235971 A JP 2002-116661 A

  The present invention has been made in view of the above-described conventional problems. In view of the problems in the conventional cleaning blade and the image forming apparatus using the conventional cleaning blade, generation of squeal due to vibration and chatter and resonance sound of the photosensitive member are generated. It is an object of the present invention to provide an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus which have a stable and good image quality while preventing image unevenness and poor cleaning.

The electrophotographic photosensitive member according to claim 1 of the present invention is
On the inner side of the hollow cylindrical photosensitive member, a cross-section perpendicular to the axial line of the photosensitive body has a C-type shape, C-shape channel the cross section in the respective ends of the C-shaped portion of the該制vibration member the damping member to have a protrusion protruding I center direction suited to insertion, and the inner side of the該制vibration member is cylindrical holding member having a recess for holding the two protrusions an electrophotographic photosensitive member comprising have a,
The damping member is
In a state where it is not inserted inside the photoconductor, it has an outer diameter larger than the inner diameter of the photoconductor,
In the state of being inserted inside the photoconductor, the two convex portions are held in the concave portions of the holding member to stabilize the expansion of the outer diameter of the damping member to an outer diameter smaller than the inner diameter of the photoconductor,
In the state of being inserted inside the photoconductor, the vibration damping member is brought into contact with the inner wall of the photoconductor to suppress fluctuations in the outer diameter of the photoconductor .

  According to a second aspect of the present invention, the surface of the damping member is an elastic resin layer.

  According to a third aspect of the present invention, the damping member is made of a damping steel plate.

  According to a fourth aspect of the present invention, the damping member is made of a damping resin.

  According to a fifth aspect of the present invention, the surface of the damping member is made of a rubber-like material.

  According to a sixth aspect of the present invention, at least one end of the vibration damping member in a direction along the axis of the photosensitive member has a tapered shape.

  According to a seventh aspect of the present invention, the holding member is made of a metal material.

  According to an eighth aspect of the present invention, the holding member is made of a resin material.

  According to a ninth aspect of the present invention, at least one end of the holding member in a direction along the axis of the photosensitive member has a tapered shape.

  According to a tenth aspect of the present invention, there is provided a groove portion constricted at a position on the opposite side in the circumferential direction of the opening portion of the vibration damping member.

  According to an eleventh aspect of the present invention, a plurality of the groove portions are provided.

  According to a twelfth aspect of the present invention, the damping member and the holding member have two or more in the longitudinal direction.

  An electrophotographic process cartridge according to a thirteenth aspect includes the electrophotographic photosensitive member according to any one of the first to twelfth aspects.

  The image forming apparatus according to claim 14 is an image forming apparatus having at least a charging unit, a laser exposure unit, a developing unit, a transfer unit, and a cleaning unit, wherein the process cartridge according to claim 12 is detachable from the apparatus main body. It is characterized by having.

  According to the present invention, even when the stick-slip between the elastic blade and the surface of the photoconductor is accelerated, the frictional vibration between the elastic blade and the surface of the photoconductor generated as a side effect is attenuated by the photoconductor, and the resonance sound of the photoconductor is In addition to being able to prevent the occurrence of occurrence, the diameter accuracy of the damping material is improved, and rotation flutter due to fluctuations in the outer diameter of the photoconductor is prevented. Occurrence can be prevented, so that high-quality images can be provided over a long period of time without generating unpleasant sound to the user.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  First, the schematic structure of an image forming apparatus that is an object of the present invention will be described. In FIG. 2, a charging device 022 for charging the surface of the photosensitive drum 021 around the photosensitive drum 021 as an image carrier, and exposure with a laser beam for forming a latent image on a uniformly charged surface. 023, a developing device 024 for forming a toner image by attaching charged toner to the latent image on the surface of the photosensitive drum 021, and a transfer device 025 for transferring the formed toner image on the photosensitive drum 021 to the transfer target. A cleaning device 026 for removing the residual toner on the photosensitive drum 021 and a neutralizing device 027 for removing the residual potential on the photosensitive drum 021 are sequentially arranged. In tandem electrophotography, monochromatic images such as black, magenta, cyan, and yellow are mainly formed on the surface of the photosensitive drum 021. In such a configuration, when image formation is performed by a negative positive method (lowering the exposure portion potential and attaching toner), the photosensitive drum whose surface is uniformly negatively charged by the charging roller 022 ′ of the charging device 022 In 021, an electrostatic latent image is formed on the surface of the photoreceptor by exposure 023, and toner is attached to the surface of the photoreceptor drum 021 by the developing device 024 to visualize the image. The toner image is transferred from the surface of the photosensitive drum 021 by the transfer device 025 formed of a transfer belt or the like, and residual toner components that have not been transferred from the photosensitive drum 021 to the transfer belt are transferred from the surface of the photosensitive drum 021 by the cleaning device 026. Removed. The toner image transferred to the surface of the transfer belt is transferred to a recording sheet conveyed from a paper feed tray by applying a bias to a secondary transfer roller at a secondary transfer unit (not shown). The residual toner component or the external additive component after the transfer is removed by the cleaning member 026. Then, the toner image on the unfixed recording paper is fixed on the recording paper by the fixing device. The photosensitive drum 021 from which the residual toner has been removed has its residual potential canceled by the charge eliminating lamp 027 and is used for the next image forming process.

  An organic photoreceptor is used for the photoreceptor drum 021. In addition, an inorganic photoreceptor such as a selenium tellurium photoreceptor, a selenium photoreceptor, a CdS photoreceptor, and an amorphous silicon photoreceptor can be used. Also, a belt shape can be used instead of a drum shape. However, it is desirable to use an organic photoreceptor that has many problems such as pollution problems and high manufacturing costs, energy saving, resource saving, ease of manufacture, high sensitivity design, low cost, and no pollution.

  The charging device 022 uses a contact roll charging method in which a high voltage is applied to the core of a charging roll placed in contact with the photosensitive drum 021 to uniformly charge the surface of the photosensitive drum 021. A corotron that discharges by applying a high voltage to the charge wire, a scorotron system, a charging brush, a charging sheet, a needle electrode, or the like can also be used. These have the advantage of being less susceptible to cleaning because they can charge the surface of the photoconductor without contact with the photoconductor, but the amount of discharge products such as ozone and NOx that are generated with the discharge. However, there is a problem in terms of durability of the photosensitive member because it is much larger than the charging roll method.

  As the transfer device 025, an intermediate transfer belt system is used, but other than this, a charge wire, a transfer roller, a needle electrode, a transfer drum, and the like can be used.

  As the cleaning device 026, it is possible to use an elastic member such as neoprene rubber, chloroprene rubber, silicon rubber, acrylic rubber, etc., but it does not cause chemical damage to the photoreceptor, and is durable, ozone resistant, and oil resistant. A cleaning blade made of polyurethane rubber having excellent properties such as properties is generally used.

  As shown in FIG. 3, the cleaning blade 029 is composed of a support member 040 that supports the craning blade and a plate-like elastic blade 039, and a free end tip (hereinafter simply referred to as an edge) of the elastic blade 039. 039c is pressed and used at a predetermined contact angle on the surface of the image carrier 021 rotating in the direction of the arrow. The untransferred toner scraped off by the elastic blade 039 is transported to a waste toner collection container (not shown) by transport means such as a transport screw 038 installed below the elastic blade 039.

  During the endurance, the toner blocked by the elastic blade 039 gradually accumulates in the vicinity of the edge 039c of the elastic blade 039. Due to the accumulation of the toner, a pressing force is applied to the elastic blade-39, and finally the elastic blade 039 is pushed up, so that the toner may slip through the edge 039c of the elastic blade 039 and cause a cleaning failure. . Therefore, in order to improve the cleaning property, it is necessary to efficiently remove the toner pool. Therefore, a material having high rebound resilience of the elastic blade 039 is selected, and the elastic restoring force is increased when the edge 039c portion of the elastic blade 039 is distorted in the rotation direction of the photosensitive drum 021 by the frictional force, so that the toner pool is increased. It is preferable that the vibration for releasing the rotation, that is, the so-called stick-slip motion is accelerated.

  However, when the vibration of the edge 039c of the elastic body blade 039 is increased in this way, the force by which the edge 039c is rubbed against the surface of the photosensitive drum 021 and the rubbed distance (in the circumferential direction of the photosensitive drum 021). ) Also increases, and this generates vibration noise that is recognized as an unpleasant noise by the user. If the frictional vibration between the edge 039c of the elastic blade 039 and the surface of the photosensitive drum 021 resonates with the photosensitive drum 021, further high-frequency noise is generated and an unpleasant sound is emitted. In order to reduce this vibration noise, a vibration damping member is inserted into the inner surface of the photosensitive drum 021 to attenuate the frictional vibration between the edge 039c of the elastic blade 039 serving as a vibration source and the surface of the photosensitive drum 021. It is effective against this.

  In this embodiment, a vibration damping material 062 having a C-shaped cross section (C-shaped in a plane perpendicular to the axial direction of the photosensitive drum 021) to be inserted into the photosensitive drum 021 is used. Has a holding member 063 for holding the convex portion 062c of the vibration damping material 062 located at the end of the C-shape. Then, the C-type damping material 062 is brought into close contact with the inner wall of the photosensitive drum 021 using a force repelling outward from the inner center of the photosensitive drum 021 to enhance the vibration proofing and damping effect, A holding member 063 having a recess 063c installed on the surface controls the C-shaped opening of the damping member 062, and the damping member 062 pushes the inner wall of the photosensitive drum 021 too much, so that the outer diameter of the photosensitive drum 021 is increased. The structure prevents the non-uniformity.

  In other words, the damping material 062 alone may be inserted into the photosensitive drum 021 by utilizing the C-shaped and elastic deformation, so that it is difficult to maintain the roundness of the cross section and the variation in diameter becomes large. As a result, the force pushing the inner wall of the photosensitive drum 021 is dispersed. As a result, the outer diameter fluctuation of the photosensitive drum 021 becomes large, which causes density unevenness and the like. By adding a holding member 063 that holds the shape by inserting a convex portion 063c at the C-shaped end of the damping material 062, the outer diameter of the damping material 062 is stabilized, and the outer diameter of the photosensitive drum 021 varies. Is suppressed.

  FIG. 4 shows the distribution of the outer diameter of the photoreceptor depending on the presence / absence of the damping member and the holding member. Further, FIG. 5 and FIG. 6 show a cross-sectional view of an example of the damping material 062 used, and diagrams of the damping material when not inserted. FIG. 7 shows an example of a cross-sectional view of the state in which the damping material and the holding member are combined.

  The damping material 062 used in this embodiment has a structure having a slit 060 extending in the axial direction of the photosensitive drum 021, and when not inserted into the photosensitive drum 021, the slit 060 is open, and the damping material 062 When a perfect circle is virtually applied to the cross section, the outer periphery of the damping material 062 is positioned outside the virtual perfect circle (see FIG. 5).

  A state in which the holding member 063 is inserted into the photosensitive drum 021 in a state in which the width of the slit 060 is reduced and the diameter is made smaller than the virtual perfect circle described above, and the vibration damping material 062 and the holding member 063 are combined. Then, it is inserted inside the photoconductor 021 in a state where it is crushed again in the direction of reducing the slit width. When the crushing force is released at a predetermined position in the axial direction of the photosensitive drum 021, the damping force of the damping material 062 itself is tightly fixed to the inner wall of the photosensitive drum 021. Since the photosensitive drum 021 also vibrates at the rotationally driven position, the insertion position of the damping material 062 is inserted close to the position where the drive transmission from the apparatus main body of the apparatus used such as the image forming apparatus main body is received. Is preferred.

  Further, the tip of the vibration damping material 062 forming the slit 060 is processed into a convex shape in the center direction of the vibration damping material 062, and as shown in FIG. 7, the holding member 063 has a concave portion 063c that regulates the position of the convex portion 062c. The opening width of the slit 060 is regulated. The opening width of the slit 060 is preferably about 0.5% to 3% of the inner diameter of the photosensitive drum 021. If this range is exceeded, the adhesion to the inner wall of the photosensitive drum 021 deteriorates, and the vibration damping member 062 may not be held. In addition, there is a region where nothing is in contact with the inner wall of the photosensitive drum 021. Therefore, the effect of attenuating the frictional vibration between the elastic blade 039 and the surface of the photosensitive drum 021 is reduced. On the other hand, if it is smaller than this range, the elastic deformation width becomes small when inserted into the photosensitive drum 021, which causes a problem in terms of workability.

  Further, in order to simplify the insertion into the inside of the photosensitive drum 021, the radius of the damping member 062 or the holding member 063 is gradually reduced in the end portion of the damping material 062 or the holding member 063 in the insertion direction. In other words, it is preferable to have a structure in which the tip end side in the insertion direction is tapered along the axial direction of the photosensitive drum 021. This not only improves the ease of insertion work but also prevents the occurrence of scratches caused by hitting the damping member 062 and the holding member 063 against the end of the photosensitive drum 021. The tapered shape may be only one end, but if both are tapered and the damping material 062 is symmetrical, the insertion direction into the photosensitive drum 021 is not restricted, and the workability is further simplified. This is preferable.

  The number of the damping material 062 and the holding member 063 accommodated in the photosensitive drum 021 is not limited to one and may be two or more. When the number of the damping materials 062 is increased, the area for suppressing the inner surface of the photosensitive drum 021 is increased, so that the vibration damping effect is remarkable.

  The vibration of the cleaning blade 029 is transmitted as vibration in the crushing direction of the photoconductive drum 021 and is generated when resonating with the natural frequency of the photoconductive drum 021. Therefore, the area closely contacting the inner wall of the photoconductive drum 021 is large. As a result, the vibration damping effect in the crushing direction of the photosensitive drum 021 is enhanced. Therefore, in order to suppress abnormal noise, it is necessary to select an area closely contacting the inner surface and a damping member that suppresses vibration transmission.

  That is, the damping member 062 is preferably made of an elastic material such as a synthetic resin or a synthetic rubber material. In order to maintain the vibration reducing effect, the thickness of the vibration damping member 062 is required to be 0.5 mm or more, and is preferably 1 mm or more and 5 mm or less in order to simplify the insertion.

  Further, if a groove portion 064 that is constricted in a concave shape in the axial direction is provided at a position 180 ° in the rotational direction of the slit 060 of the vibration damping member 062 (see FIG. 7), the force for crushing the vibration damping material 062 during insertion may be small. It becomes possible to insert more easily. It should be noted that a plurality of the groove portions may be provided to facilitate insertion, but if the damping member 062 is not in contact with 75% or more of the inner diameter of the photosensitive drum 021, the vibration damping effect is reduced and abnormal noise is generated. It is necessary to keep in mind that this will occur.

  In addition to the above, the material used for the damping material 062 is preferably a damping resin, a damping steel plate, a rubber material, or the like. The damping resin and rubber material are mainly composed of a base resin, an active ingredient, and an inorganic filler. Examples of the base resin include polyvinyl chloride, polyethylene, chlorinated polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyisoprene, polystyrene, styrene-butadiene-acrylonitrile copolymer (ABS resin). ), Styrene-acrylonitrile copolymer (AS resin), polycarbonate, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR) One kind selected from the above or a mixture thereof can be used.

  Examples of the active ingredient include N, N-dicyclohexylbenzothiazyl-2-sulfenamide (DCHBSA), 2-mercaptobenzothiazole (MBT), dibenzothiazyl sulfide (MBTS), N-cyclohexylbenzothiazyl-2- Sulfenamide (CBS), N-tert-butylbenzothiazyl-2-sulfenamide (BBS), N-oxydiethylenebenzothiazyl-2-sulfenamide (OBS), N, N-diisopropylbenzothiazyl One or two or more kinds of sulfur accelerators containing a benzothiazyl group such as 2-sulfenamide (DPBS) can be used.

  Examples of the inorganic filler include mica scale pieces, glass pieces, glass fibers, carbon fibers, calcium carbonate, barite, and precipitated barium sulfate. These inorganic fillers are filled for the purpose of further improving the vibration damping performance. The filling amount of the inorganic filler is preferably 10 to 100 parts by weight with respect to 100 parts by weight of the base resin.

  Examples of the damping steel plate include a composite damping material having a multilayer structure in which a resin intermediate layer having viscoelasticity is sandwiched between a steel plate having a thickness of 0.02 to 1 mm, a stainless foil, and an aluminum plate.

  As the viscoelastic resin intermediate layer, a resin having a glass transition point of −60 to 50 ° C. and a molecular weight of 5000 to 50000 such as polyester, polyamide, ethylene-vinyl acetate copolymer, and polyvinyl butyral having a thickness of 10 to 100 μm is used. These viscoelastic resins are used singly or in combination of two or more kinds as appropriate, and are selected and used according to the desired resin cohesive strength, adhesiveness, tackiness and vibration damping performance.

The elastic resin layer provided on the surface of the vibration damping material preferably has a thickness of 10 to 100 μm. The material of the elastic resin layer is preferably an elastomer having rubber elasticity, for example, hardness 30 to 90 (JISA) such as Epofriend (manufactured by Daicel).
The elastic resin layer can be provided on the surface of the vibration damping material by spraying, dipping or the like a resin solution dissolved in an organic solvent. The holding member may be the same resin material as described above, but may be made of a metal such as stainless steel, aluminum, nickel, phosphor bronze.

<Experimental example 1>
The following was manufactured as an experimental example of the present invention. 75 parts of ABS resin (trade name: GA-704, manufactured by Sumika A & L), 20 parts of mica (trade name: 60C, manufactured by Kuraray), and N-tert-butyl-2-benzothiazolylsulfenamide 5 as an active ingredient Using a resin composition consisting of parts, the slit width is 1.7 mm, the maximum outer diameter is 22.6 mm, the thickness is 4 mm, the length is 90 mm, and one end is tapered (taper length 8 mm). A vibration member was formed. A thermoplastic elastomer (trade name: Epofriend, manufactured by Daicel) elastic layer having a thickness of 20 μm was provided on the surface of the damping member. Further, after inserting a holding member made of SUS with a thickness of 1.5 mm processed into the above shape into the vibration damping material, the vibration damping member and one holding member pair were inserted into the photosensitive drum and elastically supported. Thereafter, resin flanges were attached to both ends of the photosensitive drum. The photosensitive drum having the vibration damping material and the holding member inserted in this way is assembled into a Cx3000 manufactured by Ricoh Co., Ltd., and the printing area ratio is 0.5% in a 32 ° C. and 54% environment, and 5000 sheets are printed in a single sheet intermittent mode. For every 1000 sheets subjected to the durability test, the occurrence of abnormal noise was confirmed at a linear speed of 120 mm / sec and 60 mm / sec, and density unevenness was confirmed by a halftone image. Further, the cleaning property was confirmed from the contamination state of the charging roll. Occurrence of unacceptable noise ○, occurrence of ×, density unevenness level visually unrecognizable ○, apparently visible ×, cleaning property is not contaminated charging roll ○, contamination is Judgment was made by Δ, which does not appear on the image, and x which is contaminated and has streaks on the image.
<Experimental example 2>
The same as in Example 1 except that a damping member was produced by processing a damping steel plate having a polyester resin (glass transition point: 10 ° C.) intermediate layer having a thickness of 40 μm between stainless steel foils having a thickness of 0.1 mm. The experiment was conducted.
<Experimental example 3>
An experiment similar to that of Example 1 was performed, except that two damping members and two holding members were inserted into the photosensitive drum.
<Comparative Example 1>
An experiment similar to that of Example 1 was performed except that the damping material and the holding member were not inserted.
<Comparative example 2>
An experiment similar to Experimental Example 1 was performed except that the holding member was not inserted.

  FIG. 8 shows a list of confirmation results after the 5000 sheet printing test for the above experimental examples and comparative examples. It can be seen that the present invention is superior in all respects.

  That is, according to the present invention, even when the stick-slip between the elastic blade and the photosensitive drum surface is accelerated in order to improve the cleaning property, the frictional vibration between the elastic blade and the photosensitive drum surface that occurs as a side effect is accelerated. In addition to preventing the resonance of the photosensitive drum from being generated, the diameter accuracy of the damping material is improved by installing a holding member that regulates the force of the damping material that pushes the photosensitive drum. Therefore, it is possible to prevent rotational flutter due to fluctuations in the outer diameter of the photosensitive drum, and to prevent occurrence of uneven image density and poor cleaning due to rotational fluff of the photosensitive drum, so that no unpleasant sound is generated to the user. A high-quality image can be provided over a long period of time.

  In addition, the vibration damping member can be easily inserted into the photosensitive drum, damage to the photosensitive drum during insertion can be reduced, production efficiency is improved, and processing accuracy of the holding member is improved. The fluctuation of the diameter of the vibration material is reduced, and hence the fluctuation of the outer diameter of the photosensitive drum is reduced, so that the fluctuation is further reduced. In addition, since the holding member also has a vibration damping effect, vibration damping is improved.

  Further, since the necessary force with respect to the direction in which the damping material is crushed can be reduced, the insertion into the photosensitive drum can be easily performed. Further, the vibration damping material can be more easily deformed, and the area ratio of the vibration damping member that is in close contact with the inner surface of the photosensitive drum is improved, so that the effect of damping vibration is improved.

A diagram showing an example of a tandem type image forming apparatus Sectional drawing which shows schematic structure of the image forming apparatus made into implementation object of this invention Sectional drawing which shows the structure of the cleaning apparatus of the apparatus of FIG. FIG. 4 shows the distribution of the outer diameter of the photosensitive member depending on the presence / absence of the damping member and the holding member. Cross section of an example of damping material Perspective view of damping material when not inserted Cross-sectional view of a combination of damping material and holding member The figure which shows the list of the confirmation result after the 5000 sheet printing test about the experiment example and comparative example of this invention

Explanation of symbols

021: Photosensitive drum 022: Charging device 022 ': Charging roller 023: Exposure 024: Development device 025: Transfer device 026: Cleaning device 027: Static elimination device 029: Cleaning blade 038: Conveying screw 039: Elastic blade 039c: Elastic body Blade free edge tip (edge)
040: Support member 060: Slit of damping material 062: Damping material 062c: Convex part of damping material 063: Holding member 063c: Concave part of holding member

Claims (14)

On the inner side of the hollow cylindrical photosensitive member, a cross-section perpendicular to the axial line of the photosensitive body has a C-type shape, C-shape channel the cross section in the respective ends of the C-shaped portion of the該制vibration member the damping member to have a protrusion protruding I center direction suited to insertion, and the inner side of the該制vibration member is cylindrical holding member having a recess for holding the two protrusions an electrophotographic photosensitive member comprising have a,
The damping member is
In a state where it is not inserted inside the photoconductor, it has an outer diameter larger than the inner diameter of the photoconductor,
In the state of being inserted inside the photoconductor, the two convex portions are held in the concave portions of the holding member to stabilize the expansion of the outer diameter of the damping member to an outer diameter smaller than the inner diameter of the photoconductor,
An electrophotographic photosensitive member characterized by suppressing fluctuations in the outer diameter of the photosensitive member by bringing the damping member into contact with the inner wall of the photosensitive member in a state of being inserted inside the photosensitive member.
  2. The electrophotographic photosensitive member according to claim 1, wherein the surface of the damping member is an elastic resin layer.   The electrophotographic photosensitive member according to claim 1, wherein the damping member is made of a damping steel plate.   The electrophotographic photosensitive member according to claim 1, wherein the damping member is made of a damping resin.   5. The electrophotographic photosensitive member according to claim 1, wherein the surface of the damping member is made of a rubber-like material.   6. The electrophotographic photosensitive member according to claim 1, wherein at least one end of the vibration damping member in a direction along the axis of the photosensitive member has a tapered shape.   The electrophotographic photosensitive member according to claim 1, wherein the holding member is made of a metal material.   The electrophotographic photosensitive member according to claim 1, wherein the holding member is made of a resin material.   9. The electrophotographic photosensitive member according to claim 1, wherein at least one end of the holding member in a direction along the axis of the photosensitive member has a tapered shape.   The electrophotographic photosensitive member according to claim 1, further comprising a groove portion constricted at a position opposite to a circumferential direction of the opening portion of the vibration damping member.   The electrophotographic photosensitive member according to claim 9, comprising a plurality of the groove portions.   The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member has two or more damping members and holding members in the longitudinal direction.   An electrophotographic process cartridge comprising the electrophotographic photosensitive member according to claim 1. An image forming apparatus comprising at least a charging unit, a laser exposure unit, a developing unit, a transfer unit, and a cleaning unit, wherein the process cartridge according to claim 12 is detachably attached to the apparatus main body.