JP2005121937A - Cleaning system, process cartridge, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improver removal of powder remaining on the electrophotographic sensitive material, even when using not only a pulverized toner but also a polymerized toner. <P>SOLUTION: A support of the cleaning blade is connected to one surface of the cleaning blade, while a suppressor plate is kept in contact with the other surface of the blade. Setting the distance from the edge of the cleaning blade to the edge of the suppressor by "L1", and the distance from the edge of the cleaning blade to the edge of the support by "L2", their relation is made "L1<L2"; as a result of this arrangement, the suppressor plate prevents the cleaning blade from vibrating and warping locally, when it comes into contact with the conductive photosensitive material. Accordingly, the edge of the cleaning blade is kept in close contact with the surface of the electrophotographic sensitive material, resulting in improved cleaning. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cleaning apparatus for cleaning residual powder on an electrophotographic photosensitive member used in an electrophotographic copying machine, a laser printer, a facsimile, and the like, a process cartridge using the cleaning apparatus, and an image forming apparatus.

  An image forming apparatus using an electrophotographic method such as a facsimile, a laser printer, an electrophotographic copying machine, or the like that has been widely spread in recent years as an apparatus for forming an image is an electrophotographic photosensitive member (hereinafter simply referred to as a photosensitive member), A charging device, an image exposure device, a developing device, a transfer device, a separation device, a cleaning device, a static elimination device, a fixing device, and the like are included.

Conventional photoreceptors used in these image forming apparatuses include amorphous selenium such as zinc oxide, cadmium sulfide, cadmium selenide, a-Se, a-As ₂ Se ₃ , a-Si: H, a- Photosensitive materials such as amorphous silicon such as Si: Ge: H and polyvinylcarbazole are used. However, due to pollution problems and problems that do not match the current era, such as high manufacturing costs, energy saving, resource saving, ease of manufacturing, high sensitivity design is possible, low cost, no pollution and organic Conversion to a photoreceptor is being attempted.

  Furthermore, the image forming apparatus has been changed from an analog system to a digital system having many functional advantages, and a photoconductor corresponding to the digital system has been developed.

  The structure of organic photoreceptors in the market includes a functionally separated photoreceptor composed of two layers of a charge generation layer and a charge transport layer on a conductive support, a charge generation material and a charge transport material. There are mixed organic photoreceptors having a single layer structure, but the mainstream is a function-separated type photoreceptor in which a charge transport layer is formed on the outermost layer.

  A function-separated type photoreceptor having the outermost layer as a charge transport layer is a 1-20 μm subbing layer, a 0.1-2 μm charge generation layer, and a 10-50 μm charge on a drum-like conductive support such as aluminum. A transport layer is laminated in order.

  By configuring the charge transport layer as the uppermost layer of the photoconductor, there is a merit that the degree of freedom in design with respect to mechanical durability is expanded. The binder resin for the charge transport layer includes amorphous polyolefin resin (APO), polystyrene resin (PS), polycarbonate resin (PC) such as A-type, C-type, and Z-type. It is greatly affected by the hazard (charge, development, damage caused by cleaning, etc.). Durability (the number of sheets in which the photosensitive layer is worn and the image quality deteriorates due to poor charging and becomes impractical) is, for example, approximately 40 to 80,000 in terms of A4 size paper when the contact charging method using DC voltage is applied. It is about a sheet.

  In the image forming apparatus, a uniform charge is applied (charged) to the photosensitive member during image formation. The charging device used in the image forming apparatus includes a corona charging method, a contact charging method, and a non-contact charging method disposed about 30 to 100 μm away from the photoreceptor (corona charging method is also a non-contact charging method). However, in the present invention, the organic photoreceptor is charged with a surface potential of about −400 to −800V. Since these charging methods are charging methods that involve discharge, discharge products (chemical substances) such as ozone and NOx are generated.

  After charging is performed almost uniformly, an electrostatic latent image is formed on the photoconductor by image exposure, and a toner image is formed on the photoconductor by the developing device. After this toner image is transferred to a transfer medium such as plain paper or an OHP film by a transfer device, residual powder (residual toner and paper dust) on the photoreceptor is removed by a cleaning device. Since the transfer efficiency of the toner image is usually about 93 to 98%, a cleaning device that removes the residual powder on the photoreceptor is an indispensable device. If a cleaning failure occurs, the charging device is contaminated. This may cause local charging failure, an afterimage phenomenon, and background stains.

  As the toner used for development, pulverized toner having an average roundness of about 0.9 with many irregularities is mainly used. However, with the recent demand for higher image quality, the roundness is 0.96 to 0.00. An approximately spherical toner of about 98 (generally called a polymerized toner because it is produced by a suspension polymerization method or an emulsion polymerization method) is gradually used. Since the polymer toner has a relatively uniform particle size, it is less likely to protrude from the image forming region, has a good image reproducibility, a good SN ratio, and a high sharpness.

  As a cleaning device, a fur brush (cleaning brush) method made up of eyelashes, eyelashes, polyester fibers, nylon fibers, etc. has been used in many cases, but now a blade that is advantageous in terms of small size, handling, manufacturing costs, etc. Cleaning methods are mainstream. However, in many cases, a fur brush and a cleaning blade are used together in a tandem type full-color printer that generates a lot of waste toner using four colors of toner or a B / W (monochrome) type high-speed system.

  It is possible to use elastic members such as neoprene rubber, chloroprene rubber, silicon rubber, and acrylic rubber for the cleaning blade used in the blade cleaning type cleaning device, but it does not cause chemical damage to the photoreceptor, Polyurethane rubber (or urethane rubber) having excellent properties such as durability, ozone resistance and oil resistance is generally used.

  In a cleaning device of a blade cleaning system, a cleaning blade cut into a strip shape (rectangular shape) is generally fixed to a support (for example, see Non-Patent Document 1).

  The cleaning performance of residual powder composed of toner, paper dust, etc. with the cleaning blade is the surface roughness of the photoconductor and the cleaning blade, the coefficient of friction of the photoconductor, the frictional resistance between the photoconductor and the cleaning blade, the hardness of the cleaning blade It depends on the elongation rate. For example, when the coefficient of friction of the photosensitive member increases, the frictional resistance between the photosensitive member and the cleaning blade increases, and the sliding force of the cleaning blade increases. For this reason, wear between the photosensitive member and the cleaning blade is promoted, and the durability of the photosensitive member and the cleaning blade is lowered, and at the same time, a gap is easily formed between the cleaning blade and the photosensitive member. In addition, when the frictional resistance is increased, the cleaning blade vibrates or is distorted, and the stick-slip phenomenon easily occurs, and a minute gap is formed between the photosensitive member and the edge of the cleaning blade. The submerged residual powder passes through the cleaning portion by the cleaning blade, and becomes a so-called poor cleaning. When this phenomenon continues, the residual powder is pressed by a charging member, a cleaning blade, and the like, resulting in a filming phenomenon that adheres to the photosensitive member, and further, the cleaning failure is increased because the frictional resistance is increased.

  Here, problems when using a polymerized toner will be described. Since the polymer toner has a spherical shape or a shape close to a spherical shape, cleaning failure is more likely to occur than the pulverized toner with many irregularities that are widely used at present. This poor cleaning is because the polymerized toner has a spherical shape and does not get caught, the blade edge is insufficiently blocked, and the toner does not move even if the clearance between the cleaning blade and the photoconductor is a small gap smaller than the toner diameter. It is presumed that it would sink under the cleaning blade while rotating.

  For this reason, it is necessary to prevent a gap from being formed between the photosensitive member and the cleaning blade in order to prevent poor cleaning when the polymerized toner is used.

  As described above, the blade cleaning type cleaning device is often used because it has both cleaning performance and compactness. However, as soon as the toner is replaced with the polymerized toner, a cleaning failure or a cleaning failure is often experienced, which is a problem in the market.

  Various inventions have been disclosed for cleaning residual powder such as toner on the surface of a photoreceptor (see, for example, Patent Documents 1, 2, 3, 4, 5, and 6).

  In the invention disclosed in Patent Document 1, a cleaning blade having a JIS-A hardness of 60 to 75 degrees is pressed against a photoconductor with a contact pressure of 25 to 60 (gf / cm), and the residual powder is thoroughly cleaned. ing. By increasing the contact pressure of the cleaning blade, the adhesion with the photosensitive member is improved and the cleaning blade is prevented from floating.

  The invention disclosed in Patent Document 2 improves the defective cleaning by preventing the residual powder from coming off by attaching a damping material to a part of the cleaning blade or the support so that the cleaning blade does not vibrate. doing.

  In the invention disclosed in Patent Document 3, a cleaning blade is attached to a support of a cleaning blade via an elastic member, and a relationship of 0.1B <A is established between the rebound resilience B of the elastic member and the rebound resilience A of the cleaning blade. By providing this, the vibration of the cleaning blade is suppressed, a strong and stable cleaning force is maintained for a long period of time, and spherical toner such as polymerized toner can be cleaned well.

  The invention disclosed in Patent Document 4 prevents the cleaning blade from floating by giving minute vibrations to the edge of the cleaning blade to dissipate residual powder accumulated (aggregated) on the edge of the cleaning blade. Then, the cleaning blade edge is sufficiently adhered to the photoreceptor to improve the residual powder cleaning failure.

  In the invention disclosed in Patent Document 5, the cleaning blade is made of a conductive material, and a ground or voltage (AC voltage or DC voltage) is applied to remove the charge held in the toner, and the polymerization toner, the small particle size toner, the polymerization This improves the toner cleaning performance.

  The invention disclosed in Patent Document 6 uses an organic photoreceptor made of a polycarbonate resin having a specific structure, and sets the linear pressure of the cleaning blade to 8 to 20 gf / cm and the pressure contact angle to 12 to 30 °. Therefore, there is little wear, and the cleaning blade is turned up, and the cleaning blade “squeal (abnormal noise)” phenomenon and the like are prevented from occurring.

The Electrophotographic Society of Japan Vol.33 No.1 (1994) JP-A-6-318022 JP 2002-196642 A JP 2001-242758 A JP 2003-43893 A JP-A-7-210053 JP 2002-268491 A

  In order to improve the cleaning property when polymerized toner is used, it is important to improve the adhesion between the photosensitive member and the cleaning blade. As a means for this, as in the invention disclosed in Patent Document 1 A method of increasing the contact pressure of the cleaning blade to the photosensitive member is more effective than when pulverized toner is used. However, problems caused by increasing the contact pressure appear on both the cleaning blade and the photoconductor. That is, by increasing the contact pressure, the frictional resistance between the photoconductor and the cleaning blade increases, so that the photoconductor is easily worn. In addition, since the frictional resistance with the cleaning blade is increased, the edge of the cleaning blade is burdened and the edge is easily distorted, so that the toner cleaning performance is temporarily improved, but the cleaning performance is deteriorated early. Occurs.

  In the case of polymerized toner, if there is a slight gap between the cleaning blade and the photoconductor, it is easy to come off, so it is important to eliminate the vibration of the cleaning blade and to ensure that the edge of the cleaning blade contacts the photoconductor. is there. Therefore, as in the invention disclosed in Patent Document 2, suppressing the vibration of the cleaning blade is to prevent a gap from being formed between the photosensitive member and the cleaning blade, which seems to be reasonable. However, vibration such as chatter due to rubbing between the photoconductor and the cleaning blade is effective when the support is as thin as 1 mm or less, but when the support is as thick as 2 mm or 3 mm, the vibration is stopped. However, if the friction coefficient becomes as high as 0.5 or 0.6 due to the adhesion of the discharge product even if filming occurs on the surface of the photosensitive member, the cleaning blade will vibrate. Since the phenomenon becomes larger and a phenomenon such as stick-slip occurs, it is difficult to obtain an improvement effect only with the damping material.

  When a small amount of distortion or gap occurs locally in the polymerized toner, the toner comes off from that portion. Therefore, it is desirable that the edge portion of the cleaning blade be in contact with the photosensitive member uniformly. However, as in the invention disclosed in Patent Document 3, an elastic member is inserted between the support member and the cleaning blade. In this method, since the edge part of the cleaning blade cannot be managed, the cleaning failure cannot be eliminated.

  In the invention disclosed in Patent Document 4, although an effect is surely recognized in the initial stage, the toner is sandwiched between the cleaning blade and the photosensitive member by vibration, and there is a tendency to gradually cause defective cleaning.

  However, in the invention disclosed in Patent Document 5, the effect of static elimination is recognized for the toner directly in contact with the cleaning blade, but the effect is low because most of the toner etc. is difficult to be neutralized, especially in the case of repeated copying. Since a large amount of toner concentrates on the cleaning blade, the effect of static elimination is lowered, and the efficiency of cleaning performance is negligible.

  As in the invention disclosed in Patent Document 6, the edge of the cleaning blade is less likely to be inverted by reducing the contact pressure of the cleaning blade to the photosensitive member and setting the pressure contact angle to be small. I think that the. However, not only the hardness of the cleaning blade but also the dimension representing the unfixed area from the tip of the support to the contact with the photosensitive member (free length of the cleaning blade), and the photosensitive member are used for the reversal of the cleaning blade. The upper friction coefficient (or the frictional resistance between the cleaning blade and the photosensitive member) is also closely related to the frequency of reversal of the cleaning blade and the “squeal” of the cleaning blade.

  Therefore, in the invention disclosed in Patent Document 6, the cleaning blade hardness (for example, JIS-A hardness measured according to JIS K 6301) is not specified, and the length of the free length is not specified. Is uncertain. In addition, since the photoconductor adheres to the discharge product due to electrification in the process of use, even if it is a polycarbonate resin having a siloxane structure, the effect is only at the initial stage, and the coefficient of friction gradually increases as it is used. (Or frictional resistance) increases, and problems such as reversal of the cleaning blade and “squealing” of the cleaning blade emerge.

  An object of the present invention is to improve the cleaning performance of residual powder on an electrophotographic photosensitive member not only when a pulverized toner is used but also when a polymerized toner is used.

  According to a first aspect of the present invention, there is provided a cleaning device having a rectangular shape having an edge portion in contact with the outer peripheral surface of an electrophotographic photosensitive member, and the cleaning blade in contact with one surface of the cleaning blade. And a distortion suppressing plate that is in contact with the other surface of the cleaning blade and sandwiches the cleaning blade by the support, and the distortion from the tip of the edge portion of the cleaning blade The dimension “L1” from the leading edge of the cleaning blade to the leading edge of the support is set to “L1 <L2” with respect to the dimension “L2” from the leading edge of the cleaning blade to the leading edge of the support. ing.

  Therefore, when cleaning the residual powder on the outer peripheral surface of the electrophotographic photosensitive member with the cleaning blade by moving the electrophotographic photosensitive member by bringing the edge portion of the cleaning blade into contact with the outer peripheral surface of the electrophotographic photosensitive member, the cleaning blade Fluctuations and local distortion of the cleaning blade are suppressed by the distortion suppression plate, the adhesion between the edge of the cleaning blade and the outer peripheral surface of the electrophotographic photosensitive member is increased, and the residual powder containing toner is removed from the cleaning blade. The contact portion between the edge portion and the outer peripheral surface of the electrophotographic photosensitive member is hardly scraped off, and the cleaning performance is improved. The image quality formed by the image forming apparatus using the cleaning device is improved.

  According to a second aspect of the present invention, in the cleaning device according to the first aspect, when the edge portion of the cleaning blade is brought into contact with the outer peripheral surface of the electrophotographic photosensitive member, the moving direction of the electrophotographic photosensitive member is increased. The distortion suppression plate and the support are positioned so that the distortion suppression plate is positioned on the downstream side along the line and the distortion suppression plate is positioned on the upstream side in the moving direction of the electrophotographic photosensitive member. .

  Therefore, it is possible to effectively suppress the fluctuation of the cleaning blade and the local distortion of the cleaning blade by the distortion suppression plate.

  According to a third aspect of the present invention, in the cleaning device according to the first or second aspect, the length dimension “L1” is 1 to 2 mm, and the length dimension “L2” is 3 to 8 mm.

  Therefore, it is possible to effectively suppress the fluctuation of the cleaning blade and the local distortion of the cleaning blade by the distortion suppression plate.

  According to a fourth aspect of the present invention, in the cleaning device according to any one of the first to third aspects, the distortion suppressing plate is formed of a metal material.

  Therefore, the distortion suppression plate made of metal material can strongly suppress local distortion and fine vibration of the cleaning blade, and the phenomenon of “squeal” that occurs when the cleaning blade vibrates in contact with the electrophotographic photosensitive member. Is also suppressed.

  According to a fifth aspect of the present invention, in the cleaning device according to any one of the first to third aspects, the distortion suppressing plate is formed of a hard plastic material.

  Therefore, the distortion suppression plate formed of a hard plastic material can strongly suppress local distortion and fine vibration of the cleaning blade, and “squeal” generated when the cleaning blade vibrates in contact with the electrophotographic photosensitive member. The phenomenon is also suppressed.

  According to a sixth aspect of the present invention, in the cleaning device according to any one of the first to fifth aspects, the width dimension from the front end side edge portion to the rear end side edge portion of the distortion suppression plate is a width of the cleaning blade. 92-54% of the dimensions.

  Therefore, the operation described in claim 1 is effectively achieved.

  According to a seventh aspect of the present invention, in the cleaning device according to any one of the first to sixth aspects, a vibration damping material is affixed to the surface of the strain suppression plate.

  Accordingly, the fine vibration of the cleaning blade is more effectively suppressed, the operation described in claim 1 is more effectively performed, and further, the phenomenon of “squealing” of the cleaning blade caused by the fine vibration of the cleaning blade. Is effectively deterred.

  According to an eighth aspect of the present invention, in the cleaning device according to any one of the first to seventh aspects, a chamfering process or a tapered cutting process is performed on the edge portion on the front end side of the distortion suppressing plate.

  Therefore, it is possible to prevent the edge side edge portion of the strain suppression plate from coming into contact with the outer peripheral surface of the electrophotographic photosensitive member and damaging the electrophotographic photosensitive member. In addition, a member having a large thickness can be used as the strain suppression plate, and the selection range of materials that can be used as the strain suppression plate is expanded. Furthermore, the front edge of the strain suppression plate is less likely to come into contact with the outer peripheral surface of the electrophotographic photosensitive member, so that the front edge of the strain suppression plate can be brought closer to the edge of the cleaning blade, thereby suppressing the distortion. It is possible to further enhance the action of the first aspect of the plate.

  According to a ninth aspect of the present invention, in the cleaning device according to any one of the first to eighth aspects, the cleaning blade is made of polyurethane rubber and has a JIS-A hardness of 58 to 85 degrees.

  Therefore, by using the strain suppression plate, even if a cleaning bleed having a low JIS-A hardness is used, the cleaning blade is prevented from turning up due to sliding contact with the electrophotographic photosensitive member, and the JIS-A hardness is low. By using the cleaning blade made of the material, the adhesion of the cleaning blade to the outer peripheral surface of the electrophotographic photosensitive member is increased, and the cleaning property is improved, and the damage to the outer peripheral surface of the electrophotographic photosensitive member is reduced.

  According to a tenth aspect of the present invention, in the cleaning device according to any one of the first to ninth aspects, the contact pressure of the cleaning blade against the outer peripheral surface of the electrophotographic photosensitive member is 10 to 25 gf / cm.

  Therefore, in order to ensure the cleaning performance by the cleaning blade, it is desirable to set the contact pressure of the cleaning blade to 10 to 25 gf / cm when using pulverized toner, and when using polymerized toner, It is desirable to set it above. However, the higher the contact pressure, the lower the durability of the cleaning blade and the electrophotographic photosensitive member. However, by using a strain suppression plate, the cleaning performance is ensured even when the contact pressure is set to the same level as when pulverized toner is used when polymerized toner is used, and the cleaning blade and the electrophotographic photosensitive member can be secured. Durability is maintained.

  According to an eleventh aspect of the present invention, in the cleaning device according to any one of the first to tenth aspects, the surface roughness of the edge portion of the cleaning blade is 10 μm or less.

  Therefore, even if a cleaning blade having a large surface roughness of 10 μm is used, the use of a strain suppression plate improves the adhesion of the edge of the cleaning blade to the outer peripheral surface of the electrophotographic photosensitive member, and cleaning. Performance is maintained.

  A process cartridge according to a twelfth aspect of the present invention is an electrophotographic photosensitive member having a toner image formed on an outer peripheral surface thereof, a cartridge case for rotatably holding the electrophotographic photosensitive member, and being held in the cartridge case, The cleaning device according to claim 1, wherein the cleaning device is disposed to face an outer peripheral surface of the electrophotographic photosensitive member.

  Here, the process cartridge accommodates at least one of an electrophotographic photosensitive member on which a toner image is formed and an image forming means (charging device, developing device, cleaning device, etc.) involved in the formation of the toner image in a cartridge case. Thus, the unit is detachably attached to the image forming apparatus.

  Therefore, this process cartridge has the same operation as that of any one of the first to eleventh aspects.

  Furthermore, by using this process cartridge, when a failure occurs in a member involved in the formation of a toner image arranged around the electrophotographic photosensitive member, the process cartridge may be replaced as a whole, and maintenance performance is improved. In addition, by housing the cleaning device in the process cartridge, the electrophotographic photosensitive member is improved in cleaning property, and the life of the electrophotographic photosensitive member is extended. As a result, the life of the process cartridge is extended.

  According to a thirteenth aspect of the present invention, there is provided an image forming apparatus comprising: an electrophotographic photosensitive member having a toner image formed on an outer peripheral surface thereof; a charging device that uniformly charges the outer peripheral surface of the electrophotographic photosensitive member; An exposure device that writes an electrostatic latent image on the outer peripheral surface of the electrophotographic photosensitive member, a developing device that develops the electrostatic latent image written on the outer peripheral surface of the electrophotographic photosensitive member to form a toner image, and development A transfer device that transfers the toner image to a recording medium, and a cleaning device according to any one of claims 1 to 11 disposed opposite to the outer peripheral surface of the electrophotographic photosensitive member.

  Therefore, this image forming apparatus has the same operation as that of any one of claims 1 to 11.

  An image forming apparatus according to a fourteenth aspect of the present invention is provided in the apparatus main body, and is detachably disposed in the middle of the recording medium conveyance path from the recording medium accommodating section to the recording medium discharge section, and the recording medium conveyance path. And a process cartridge according to claim 12.

  Therefore, according to this image forming apparatus, the same operation as that of the invention described in claim 12, that is, the same operation as that of any one of claims 1 to 11 is achieved.

  According to the cleaning device of the first aspect of the present invention, when cleaning the residual powder on the outer peripheral surface of the electrophotographic photosensitive member by bringing the edge portion of the cleaning blade into contact with the outer peripheral surface of the electrophotographic photosensitive member, the cleaning blade Fluctuations and local distortion of the cleaning blade can be suppressed by the distortion suppression plate, the adhesion between the edge of the cleaning blade and the outer peripheral surface of the electrophotographic photosensitive member is increased, and residual powder containing toner is removed from the cleaning blade. The contact portion between the edge portion and the outer peripheral surface of the electrophotographic photosensitive member is hardly scraped off, so that the cleaning performance can be improved and the quality of the formed image can be improved.

  According to the cleaning device of the second aspect, it is possible to effectively suppress the fluctuation of the cleaning blade and the local distortion of the cleaning blade by the distortion suppression plate.

  According to the cleaning device of the third aspect of the present invention, it is possible to effectively suppress the fluctuation of the cleaning blade by the distortion suppression plate and the local distortion of the cleaning blade.

  According to the cleaning device of the fourth aspect of the present invention, it is possible to suppress the phenomenon of “squeal” that occurs when the cleaning blade comes into contact with the electrophotographic photosensitive member and vibrates.

  According to the cleaning device of the fifth aspect of the present invention, the phenomenon of “squeal” that occurs when the cleaning blade comes into contact with the electrophotographic photosensitive member and vibrates can be suppressed.

  According to the cleaning device of the sixth aspect, the effect described in the first aspect can be effectively obtained.

  According to the cleaning device of the seventh aspect of the present invention, the fine vibration of the cleaning blade can be more effectively suppressed, the effect described in the first aspect can be more effectively achieved, and further, the cleaning can be performed. The phenomenon of “squealing” of the cleaning blade that occurs when the blade vibrates slightly can be effectively suppressed.

  According to the cleaning device of the eighth aspect of the present invention, it is possible to prevent the edge side edge portion of the distortion suppressing plate from coming into contact with the outer peripheral surface of the electrophotographic photosensitive member to damage the electrophotographic photosensitive member, thereby the distortion suppressing plate. 2. The strain suppressing plate according to claim 1, wherein a selection range of materials that can be used as the first and second edge portions of the cleaning blade can be made closer to the edge portion of the cleaning blade. The effect can be further enhanced.

  According to the cleaning device of the ninth aspect of the present invention, even when a cleaning bleed having a low JIS-A hardness is used, the cleaning blade can be prevented from turning up due to sliding contact with the electrophotographic photosensitive member. By using a cleaning blade made of a material with low hardness, the cleaning property can be improved by increasing the adhesion of the cleaning blade to the outer peripheral surface of the electrophotographic photosensitive member.

  According to the cleaning device of the tenth aspect of the present invention, when the polymerization toner is used, the contact pressure of the cleaning blade to the outer peripheral surface of the electrophotographic photosensitive member is preferably 10 to 10 when the pulverized toner is used. Even when set to 25 gf / cm, good cleaning characteristics can be obtained, and the cleaning performance can be improved while preventing the durability of the cleaning blade and the electrophotographic photosensitive member from being lowered by increasing the contact pressure. it can.

  According to the cleaning device of the eleventh aspect, even when a cleaning blade having a large surface roughness of the edge portion is used, the adhesion of the edge portion of the cleaning blade to the outer peripheral surface of the electrophotographic photosensitive member can be improved. Can maintain the cleaning performance.

  According to the process cartridge of the twelfth aspect of the present invention, it is possible to achieve the same effects as the invention of any one of the first to eleventh aspects, and further, it is possible to improve the maintainability and extend the life. it can.

  According to the image forming apparatus of the thirteenth aspect of the invention, the same effect as that of the first aspect of the invention can be achieved.

  According to the image forming apparatus of the fourteenth aspect, the same effect as that of the twelfth aspect can be achieved.

  A first embodiment of the present invention will be described with reference to FIGS. 1 is a schematic side view showing a printer which is an electrophotographic image forming apparatus, FIG. 2 is a perspective view showing a part of a cleaning apparatus, and FIG. 3 is a longitudinal side view showing a part of the cleaning apparatus in an enlarged manner. 4 is a cross-sectional view showing the structure of the photoreceptor.

  In this printer, a drum-shaped photosensitive member 1 which is an electrophotographic photosensitive member is disposed at a substantially central portion in a main body case (not shown), and the photosensitive member 1 is supported so as to be rotatable around a center line. . The rotation around the center line of the photoconductor 1 is performed by driving a motor (not shown) connected to a rotation shaft (not shown) of the photoconductor 1 via a gear or the like.

  Around the photosensitive member 1, as a member for forming a toner image on the outer peripheral surface of the photosensitive member 1, a charging device 2 that uniformly charges the outer peripheral surface of the photosensitive member 1, and an outer peripheral surface of the charged photosensitive member 1 Is exposed in accordance with image data to form an electrostatic latent image on the outer peripheral surface of the photosensitive member 1, and the electrostatic latent image formed on the outer peripheral surface of the photosensitive member 1 is developed with toner to form a toner image. A developing device 4 for forming the toner image, a transfer device 5 for transferring the formed toner image to the recording medium S conveyed to the transfer position, and a separating device for separating the recording medium S to which the toner image has been transferred from the outer peripheral surface of the photoreceptor 1. 6. A cleaning device 7 for cleaning residual powder (toner, paper dust, etc.) adhering to the outer peripheral surface of the photoreceptor 1 after the toner image is transferred is disposed.

  A recording medium accommodating portion 8 that accommodates the recording medium S is provided in the lower part of the main body case, and reaches the recording medium discharge portion 9 from which the recording medium S to which the toner image is transferred is discharged. A recording medium conveyance path 10 is formed. On the recording medium conveyance path 10, the above-described photoreceptor 1, transfer device 5, fixing device 11 that melts and fixes the toner image transferred to the recording medium S, and the like are disposed.

  Hereinafter, the components used in the printer of the present invention will be individually described in detail.

<Photoreceptor 1>
As shown in FIG. 4, the photoreceptor 1 includes a conductive support 101, an undercoat layer 102, a charge generation layer 103, and a charge transport layer 104.

<Conductive support 101>
The conductive support 101 is mainly in the form of a drum except for special ones. The material is mechanical strength, workability (cutting performance), electrical characteristics, etc. required for the conductive support 101 of the photosensitive member 1. An aluminum alloy of JIS standard 3003 which is excellent in the above is suitably used.

  The conductive support 101 is cut so that characteristics such as roundness, straightness, and runout are within the specified values, and finally finished with a surface finish (superfinishing or (Mirror finish) is given.

As the conductive support 101 in the case where the photoreceptor 1 is an organic photoreceptor, a conductive support having a thickness of 0.6 to 3 mm and an outer diameter of about 25 to 100 mm is used. It is sufficient that the electrical resistance of the conductive support 101 is 10 ⁶ Ω · cm or less in terms of volume resistivity, and if the volume resistivity is on the order of about 10 ⁹ Ω · cm, it can be used without damaging the electrophotographic characteristics. it can. As the electric resistance increases, the movement of carriers is limited, so that the light attenuation characteristic becomes gradual and the electrophotographic characteristics deteriorate. In aluminum, an insulating oxide film (Al ₂ O ₃ ) is formed immediately after cutting, but the oxide film formed in the atmosphere is thin, weak, and non-uniform, so it is insufficient as a charge injection blocking film. . Therefore, a thin film (also referred to as an undercoat layer or an intermediate layer) that has an insulating property to alumite treatment or to retain a charge during charging (a hole during negative charging) until the development is completed (up to several tens of msec). ) Is desirable.

  Note that since the alumite layer has a high resistance, the residual potential is likely to accumulate as the film thickness increases. For this reason, it is necessary to control the film thickness to about several tens to several hundreds of meters, and the cost is high. Therefore, the undercoat layer made of an alumite layer is limited to a part of the photoconductors, and most of the photoconductors often form an undercoat layer (below) made of a resin in which inorganic fine particles are dispersed.

<Undercoat layer 102>
The purpose of forming the undercoat layer 102 is to ensure the charging potential, electrostatic contrast, and uniform image (moire prevention, dot pattern reproduction, etc.) necessary for image formation, and is essential for digital image forming apparatuses. It is. The film thickness for preventing charge injection and preventing deterioration of electrophotographic characteristics is about 1 to 10 μm, and preferably 3 to 5 μm.

  In this case as well as the above-described anodized layer, if the thickness is too large, the carrier canceling rate on the conductive support 101 side is reduced, residual charges are accumulated in the photosensitive layer, the light attenuation characteristics are deteriorated, the charging characteristic potential is increased. Changes in characteristics such as an increase in image quality and a tendency to cause positive charging, resulting in problems such as a decrease in image density, an afterimage, and a carrier being easily attached during development.

  Examples of the resin used for the undercoat layer 102 include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane resins, melamine resins, and alkyds. Examples thereof include curable resins that form a three-dimensional network structure, such as melamine resins and epoxy resins. Further, fine powders such as metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like, or metal sulfides and metal nitrides may be dispersed and contained. These undercoat layers 102 can be formed using an appropriate solvent and coating method.

  Further, as the undercoat layer 102 of the present invention, a metal oxide layer formed by using, for example, a sol-gel method using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like is also useful.

<Charge generation layer 103>
The charge generation layer 103 is a layer that generates electron-hole pairs necessary for image formation by photons irradiated from the exposure device 3, and the sensitivity increases as the amount of electron-hole pairs generated increases. In order to smoothly move electrons or holes generated by image exposure toward the surface or the charge of the conductive support 101, the charge transport layer 104 or the undercoat layer 102 in contact with the charge generation layer 103 It is desirable that the barrier at the interface is as low as possible, and any material can be used for the photoreceptor 1 of the present invention, regardless of whether it is an inorganic material or an organic material, as long as it satisfies this condition.

  Examples of the charge generating material of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, and amorphous silicon.

  Examples of organic charge generating materials include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, diphenylamine An azo pigment having a skeleton, an azo pigment having a dibenzothiophene skeleton, an azo pigment having a fluorenone skeleton, an azo pigment having an oxadiazol skeleton, an azo pigment having a bis-stilbene skeleton, an azo pigment having a distyryl oxadiazol skeleton, Azo pigments having a distyrylcarbazole skeleton, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and the like Azomethine pigments, indigoid pigments, bisbenzimidazo - such as Le based pigments.

  A binder resin is used as necessary for the charge generation layer 103. As the binder resin, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, polyarylate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, Polyvinyl ketone, polystyrene, poly-N-vinyl carbazole, polyacrylamide and the like are used. These binder resins can be used alone or as a mixture of two or more. Further, a low molecular charge transport material (electron transport material or hole transport material) may be added as necessary.

  Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7- Examples thereof include electron accepting substances such as trinitrodibenzothiophene-5,5-dioxide. These electron transport materials can be used alone or as a mixture of two or more.

  Examples of the hole transport material include electron donating materials shown below. For example, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styryl Examples include pyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives. These hole transport materials can be used alone or as a mixture of two or more.

  The charge generation layer 103 is formed of a charge generation material, a solvent, and a binder resin as main components, and includes any additive such as a sensitizer, a dispersant, a surfactant, and silicone oil. May be included.

  Examples of the method for forming the charge generation layer 103 include a vacuum thin film manufacturing method and a casting method from a solution dispersion system. As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be used favorably. Further, in order to provide the charge generation layer 103 by the casting method, a ball mill, an attritor or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane or butanone together with a binder resin if necessary with the inorganic or organic charge generation material described above. It can be formed by dispersing with a sand mill or the like, and applying the solution after diluting the dispersion appropriately. The application can be performed using a dip coating method, a spray coating method, a bead coating method, or the like.

  The film thickness of the charge generation layer 103 provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm. Usually, it is applied to a thickness of 0.1 to 0.3 μm.

  If the charge generation layer 103 is too thin, a sensitivity failure occurs. However, if the charge generation layer 103 is too thick, light attenuation deterioration due to space charge and a residual potential increase occur, leading to a decrease in image quality such as a decrease in image density and a decrease in resolution.

<Charge transport layer 104>
The charge transport layer 104 is formed to ensure a sufficient charging potential and a sufficient contrast potential necessary for image formation. The charge transport layer 104 generally has little polarity dependency, and polycarbonate resin (A type, C type, Z type, etc.) having a volume resistivity of about 10 ¹⁴ to 10 ¹⁸ Ω · cm, styrene resin, non- A crystalline polyolefin resin or the like is used as a binder resin, and a donor, an antioxidant, a leveling material, and the like are further added.

  As the low-molecular charge transport material constituting the charge transport layer 104, an oxazole derivative, an oxadiazole derivative, an imidazole derivative, a triphenylamine derivative, an α-phenylstilbene derivative, a toniphenylmethane derivative, an anthracene derivative, or the like can be used. it can.

On the other hand, as the polymer charge transport material constituting the charge transport layer 104, the following known polymer charge transport materials can be used. For example,
1) In the polymer having a carbazole ring in the main chain and / or side chain,
Examples thereof include poly-N-vinylcarbazole, compounds described in JP-A-50-82056, JP-A-54-9632, JP-A-54-11737, and JP-A-4-183719.

2) For polymers having a hydrazone structure in the main chain and / or side chain,
For example, there are compounds described in JP-A-57-78402 and JP-A-3-50555.

3) Polysilylene polymers include
For example, there are compounds described in JP-A-63-285552, JP-A-5-19497, and JP-A-5-70595.

4) For polymers having a tertiary amine structure in the main chain and / or side chain,
For example, N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-13061, JP-A-1-19049, JP-A-1-1728, JP-A-1-105260 And compounds described in JP-A-2-167335, JP-A-5-66598, and JP-A-5-40350.

5) Other polymers include
For example, there are formaldehyde condensation polymers of nitropyrene, compounds described in JP-A Nos. 51-73888 and 56-150749, and the like.

  The polymer having an electron donating group used in the present invention is not limited to the above polymer, but also a copolymer of known monomers, a block polymer, a graft polymer, a star polymer, and, for example, It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-3-109406.

  Further, as the polymer charge transport material in the present invention, a polycarbonate having a triarylamine structure in the main chain and / or side chain is effectively used.

  On the other hand, examples of the polymer compound that can be used as the binder component include polystyrene, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer, polyester resin, polyvinyl chloride, and chloride. Vinyl / vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, polycarbonate resin (bisphenol A type, bisphenol C type, bisphenol Z type or copolymers thereof), cellulose acetate resin, ethyl cellulose resin, polyvinyl Thermoplastic or thermal such as butyral, polyvinyl formal, polyvinyl toluene, acrylic resin, silicone resin, fluorine resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin Including but of resin, but is not limited thereto. These polymer compounds can be used singly or as a mixture of two or more kinds, or copolymerized with a charge transport material.

  Examples of the dispersion solvent that can be used in preparing the charge transport layer coating solution include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, ethers such as dioxane, tetrahydrofuran, and ethyl cellosolve, toluene, xylene, and the like. Examples include aromatics, halogens such as chlorobenzene and dichloromethane, and esters such as ethyl acetate and butyl acetate, but it is desirable to avoid the use of halogen-based solvents in consideration of environmental destruction.

  In the present invention, for the purpose of improving the environmental resistance and preventing the decrease in sensitivity and the increase in residual potential, the charge generation layer 103, the charge transport layer 104, and the undercoat layer 102 are provided with an antioxidant and a plastic layer. Agents, lubricants, UV absorbers, and low molecular charge transport materials can be added.

  The thickness of the charge transport layer 104 is set in the range of about 10 to 50 μm, but is preferably set in the range of 20 to 35 μm, and is set to 15 to 25 μm when high resolution is desired. This is because if the film thickness is 10 μm or less, the capacitance becomes too large, and the surface potential necessary for image formation cannot be secured. For image formation, a contrast potential of at least 250 V is required, but if it is 10 μm or less, it becomes difficult to secure the contrast potential, the usable time becomes extremely short due to wear of the photosensitive layer, and further, the contrast potential can be secured. It becomes difficult. On the other hand, when the film thickness is reduced, it is difficult to produce a photosensitive layer having a uniform film thickness, and image defects due to density unevenness and pinholes occur, resulting in an image quality with a poor SN ratio.

  On the other hand, when the thickness of the charge transport layer 104 is increased, the electrostatic capacity is reduced, so that a sufficient surface potential is ensured and an image quality with a good SN ratio can be obtained. However, as the thickness increases, structural defects relatively increase in the charge transport layer 104, which hinders the movement of carriers (in this case, holes) and easily causes undesirable phenomena such as afterimages. Usually, it is sufficient that the contrast potential necessary for image formation is 400 to 500 V. As image forming conditions, for example, when the surface potential of the photosensitive member 1 is −800 V, the image portion potential is −300 V or less, and the developing bias. Is set to about -650V to -700V.

The 10-point average roughness Rz _JIS (JIS B 0601) at the initial stage of the surface roughness of the photoreceptor 1 is preferably 0.1 μm or more and 1.0 μm or less. This is to obtain a sharp image quality regardless of the roughness of the surface of the photoreceptor 1. When the cleaning blade 12 of the cleaning device 7 is brought into contact with the outer peripheral surface of the photoreceptor 1, the edge of the cleaning blade 12 is obtained. This is a condition for preventing a defective cleaning due to distortion in the portion 13. As the surface roughness of the photosensitive member 1 becomes smaller, the adhesiveness of the cleaning blade 12 is improved. However, since the organic photoreceptor 1 has a frictional resistance that increases as the surface roughness decreases, a stick-slip phenomenon, local distortion of the cleaning blade 12, “squealing” of the cleaning blade 12, and the like are likely to occur. It is not preferable to be too small. The limit is 0.1 μm.

  Further, when the surface roughness of the photoreceptor 1 is increased, the frictional resistance is relieved, but the image quality and cleaning properties are affected. As the toner, either a pulverized toner or a polymerized toner is used. For example, when a pulverized toner having an average particle diameter of 5 μm is used, the toner includes a toner having a small particle diameter of 1 μm or 2 μm. Yes. When such a toner is used, if the surface roughness of the photoconductor 1 is large, it causes cleaning failure. However, the surface roughness of the cleaning blade 12 is not 0 μm. Defects are likely to occur. Further, the surface roughness of the photosensitive member 1 gradually increases due to rubbing of the cleaning blade 12, developer carrier, paper dust (talc, etc.), and the like. Accordingly, it is preferable that the initial value of the surface roughness of the photosensitive member 1 is small. Considering the time-dependent and required durability, etc., the object is almost achieved if the thickness is 1.0 μm or less unless there is an abnormality such as paper jam. I can do it.

  That is, the surface roughness of the photosensitive member 1 gradually increases because the photosensitive member 1 undergoes hazards during charging, development, transfer, and cleaning. Therefore, it is desirable to keep it low at the start of use.

  When polymerized toner having a high degree of circularity, whose use has been increasing in recent years, is used, if the surface roughness of the photoconductor 1 is large and the friction coefficient of the photoconductor 1 is large, the edge portion 13 of the cleaning blade 12 is also easily distorted. For this reason, the phenomenon of toner sinking between the edge portion 13 of the cleaning blade 12 and the outer peripheral surface of the photosensitive member 1 is likely to occur, and further cleaning failure occurs. The toner is becoming increasingly smaller in particle size, and when 5 μm or 4 μm polymerized toner is used, defective cleaning becomes increasingly problematic. Therefore, it is important to take measures to keep the surface roughness of the surface of the photoreceptor 1 as low as possible.

In the present invention, the photosensitive member 1 having high wear resistance can also be used. As the photoconductor 1 with improved wear resistance, (1) the translucent property is good on the charge transport layer 104, the volume resistivity is 10 ¹² to 10 ¹⁴ (Ω · cm), and the surface resistivity is 10 ¹⁴ Ω or more. A thin film having a non-dielectric constant of about 2 to 5 and having a thickness of about 0.5 to 5 μm is formed. (2) A protective layer in which metal oxide fine particles are dispersed is formed. (3) There are several methods such as forming the second charge transport layer 105 in which metal oxide fine particles (inorganic filler) are dispersed on the outermost layer of the charge transport layer 104 (see FIG. 5).

  In (1), a DLC (Diamond-Like Carbon) film, an amorphous carbon film, and an amorphous silicon film are formed. In (2), 50% by weight of fine particles having an average particle diameter of 0.01 to 0.1 μm, such as titanium oxide, alumina, tin oxide, and zinc oxide, are added to polycarbonate resin, amorphous polyolefin resin, acrylic resin, and the like. In (3), the inorganic filler described above is added to the charge transport material. However, as described in the sections of the undercoat layer 102 and the charge transport layer 104, caution is required for the residual potential and its accumulation, and it is necessary to consider together with additives that reduce the residual potential. is there.

  FIG. 5 shows the photoconductor 1 a on which the second charge transport layer 105 is formed. The second charge transport layer 105 contains an inorganic filler. Durability depends on the amount of inorganic filler added, particle size, and material type. When α-alumina is used as the inorganic filler, the average particle size of the added inorganic filler is suitably about 0.1 to 0.5 μm. The amount is about 15 to 30% by weight of the total weight of the second charge transport layer 105 to which the inorganic filler is added. The film thickness of the second charge transport layer 105 is desirably 10 μm or less, and preferably about 3 to 6 μm. Durability varies somewhat depending on the copying system used, but is about 20 to 300,000 sheets. When the corona charging method is used for charging, the number of durable sheets can be further extended.

  Even in this case, as described above, the surface roughness is desirably suppressed to 0.1 to 1.0 μm in the initial stage. However, if the surface roughness can be suppressed to 3 μm or less over time, the polymerized toner has a small particle size in the future. Even if the thickness is increased (for example, about 4 μm), the cleaning property can be ensured. However, in order to ensure the cleanability, it is more certain that the measures for reducing the friction coefficient of the photoreceptor 1 described later are performed together.

<Cleaning device 7>
The cleaning device 7 includes a storage case 14, a support 15 that is a part of the storage case 14, a cleaning blade 12 supported by the support 15, a strain suppression plate 16 that holds the cleaning blade 12 between the support 15, and a storage case 14 includes a cleaning brush 17 and the like housed in 14. The cleaning blade 12 is formed of a polyurethane rubber in a rectangular shape, and one side thereof is an edge portion 13 that comes into contact with the outer peripheral surface of the photosensitive member 1, and the edge portion 13 extends in parallel with the center line of the photosensitive member 1 and is exposed to light. The outer peripheral surface of the body 1 is in contact with the entire area along the direction of the center line of the photoreceptor 1.

  The positional relationship among the cleaning blade 12, the support 15, and the strain suppression plate 16 is such that the planar portion of the support 15 is brought into contact with one surface of the cleaning blade 12 and the strain suppression plate 16 is in contact with the other surface of the cleaning blade 12. The flat portion is brought into contact, and the cleaning blade 12 is sandwiched between the support 15 and the strain suppression plate 16. The cleaning blade 12 and the support 15 are bonded with an adhesive (for example, hot melt adhesive, double-sided adhesive, etc.), and the cleaning blade 12 and the strain suppression plate 16 are fixed with screws 18 (see FIG. 2), or , Glued with adhesive. When the edge portion 13 of the cleaning blade 12 is in contact with the outer peripheral surface of the photosensitive member 1, the distortion suppression plate 16 is positioned on the downstream side along the rotational direction (moving direction) of the photosensitive member 1. The support body 15 is positioned on the upstream side in the direction (movement direction).

  Here, when the cleaning blade 12 is supported only by the support 15 without using the strain suppression plate 16, the edge portion 13 of the cleaning blade 12 is exposed to light when the coefficient of friction (or frictional resistance) of the photoreceptor 1 is high. When dragged in the rotation direction of the body 1, local distortion occurs or a stick-slip phenomenon occurs, and a gap is formed between the edge portion 13 and the photoreceptor 1, resulting in poor cleaning such as toner removal. Such poor cleaning becomes more serious as the dimension (free length of the cleaning blade 12) from the tip of the edge 13 of the cleaning blade 12 to the edge 15a of the support 15 is longer. In order to prevent such poor cleaning, it is necessary to use a cleaning blade having a high JIS-A hardness (for example, 90 degrees or 95 degrees in JIS-A hardness) so that the cleaning blade is not distorted. Occurs. However, in that case, the cleaning blade becomes hard and the flexibility becomes poor, so that the photoconductor 1 is liable to be rubbed at the contact portion with the photoconductor 1. Further, when residual powder such as toner is sandwiched between the edge portion 13 of the cleaning blade 12 and the outer peripheral surface of the photosensitive member 1, the photosensitive member 1 is scratched or the edge portion 13 of the cleaning blade 12 is missing. In other words, the image quality is constantly reduced.

  On the other hand, by providing the strain suppression plate 16, even when the coefficient of friction (or frictional resistance) of the photosensitive member 1 is high, the edge portion 13 of the cleaning blade 12 is dragged in the rotation direction of the photosensitive member 1 and locally. It is possible to prevent distortion and a stick-slip phenomenon, and the cleaning performance by the cleaning blade 12 is improved. Further, by providing the strain suppression plate 16, the strength of the cleaning blade 12 can be increased, the floating from the photoreceptor 1 can be prevented, and the cleaning power for the residual powder can be increased. Therefore, it is necessary that the strain suppression plate 16 is sufficiently bonded to the leading edge portion 16a. Further, by providing the distortion suppression plate 16, the contact pressure of the cleaning blade 12 to the photosensitive member 1 can be reduced, so that the photosensitive member 1 is less likely to be rubbed and scratched. Since it becomes difficult to wear, the durability of the photoreceptor 1 can be improved.

  The shape of the edge portion 13 of the cleaning blade 12 may be a flat shape over the entire thickness dimension of the cleaning blade 12 as shown in FIG. 2, but the edge portion 13 has a tip width dimension “a” as shown in FIG. "" May be cut into a knife edge shape of 0.5 to 1 mm.

  Next, the dimensional relationship, materials, etc. of the cleaning blade 12, the support 15 and the strain suppression plate 16 will be described. The cleaning blade 12 is formed of polyurethane rubber having a thickness dimension of 1.5 to 5 mm, preferably 1.5 to 3 mm, a JIS-A hardness of 58 to 85 degrees, and a rebound resilience of 30 to 70%. ing. The support 15 is formed of aluminum having a thickness dimension of about 2 to 3.5 mm, an iron plate having a thickness dimension of about 1 to 2 mm, and the like. The strain suppression plate 16 is a stainless steel plate or iron plate having a thickness of about 0.2 to 1 mm, an aluminum plate having a thickness of about 1 to 3 mm, a hard plastic plate having a thickness of about 2 to 5 mm (acrylic resin, polycarbonate resin, etc. ), A resin containing metal fine powder or the like. When a metal having a small density and a small thickness (for example, an aluminum plate having a thickness of about 0.5 mm) is used, the vibration of the cleaning blade 12 can be suppressed more effectively by using a vibration damping material described later. become.

  The length dimension “L1” from the tip of the edge 13 of the cleaning blade 12 to the tip side edge 16a of the strain suppression plate 16 is from the tip of the edge 13 of the cleaning blade 12 to the tip side edge 15a of the support 15. The length dimension “L2” is set to “L1 <L2”. However, L1 is preferably 1 to 2 mm, and L2 is preferably 3 to 8 mm. By setting L1 and L2 to such values, the fluctuation of the cleaning blade 12 and the local distortion of the cleaning blade 12 due to the action of the distortion suppression plate 16 are effectively suppressed.

  Even when the friction coefficient of the photosensitive member 1 is about 0.4 and the cleaning blade 12 in contact with the photosensitive member 1 vibrates and “squeal” is generated, the cleaning blade 16 can be provided by providing the distortion suppressing plate 16. 12 can be suppressed, and even if the friction coefficient of the photosensitive member 1 is increased to about 0.5, the “squeal” of the cleaning blade 12 can be suppressed to a range where no uncomfortable feeling is felt.

  L1 is set to 1 to 2 mm so that the edge portion 13 of the cleaning blade 12 is not distorted due to a foreign matter or a nonuniform friction coefficient on the surface of the photosensitive member 1, and the cleaning blade 12 is not reversed. It is to make it. By setting L1 to 1 to 2 mm, the edge portion 13 of the cleaning blade 12 is surely brought into contact with the photoreceptor 1 even when the friction coefficient increases. This L1 is preferably as short as possible, but is set in consideration of the contact angle and contact pressure (linear pressure) of the cleaning blade 12 to the photosensitive member 1. If it is 1 mm or less, the risk of contact with the photoreceptor 1 increases, and if it is 2 mm or more, it becomes difficult to correct the distortion of the edge portion 13.

  On the other hand, L2 is set to 3 to 8 mm in order to maintain elasticity. If the length is longer, the distortion of the cleaning blade 12 becomes larger. The shorter the length, the stronger the contact of the cleaning blade 12 against the photosensitive body 1 becomes. Increased chance of scratching. It is preferably about 4 to 7 mm, and if it becomes narrow to about 1 mm or 2 mm, the toner stays, and in some cases, cleaning failure may occur.

  The width of the adhesion of the strain suppression plate 16 to the cleaning blade 12 does not have to be a dimension obtained by subtracting the dimension of “L1” from the width dimension of the cleaning blade 12, but as shown in FIG. The width dimension “Lb” from the front end side edge 16a to the rear end side edge 16b of the distortion suppression plate 16 may be set to 92 to 54% with respect to “La”. In addition, the area | region where the distortion suppression board 16 and the support body 15 have overlapped in the width dimension direction is ensured 3 mm or more. If the area where the strain suppression plate 16 and the support 15 overlap in the width dimension direction is 3 mm or less, even if the distortion strength of the edge portion 13 of the cleaning blade 12 is increased, the overall strength is insufficient. When using polymerized toner, cleaning failure is likely to occur. On the other hand, if the ratio is 54% or less, the adhesion and distortion strength of the cleaning blade 12 to the photosensitive member 1 are insufficient, and the photosensitive member 1 has a high friction coefficient (about 0.4 or more in the Euler belt method), or the edge portion 13. In the case where there is a weak point such as when a defect occurs, cleaning failure is likely to occur. The dimension in the length direction of the strain suppression plate 16 (the dimension in the length direction of the front end side edge portion 16a) has the same dimension as the length direction of the cleaning blade 12 in terms of deformation, distortion, and the like due to contact pressure. However, it is practically practical even if it is within 5 mm from both ends.

  The surface roughness of the edge portion 13 that contacts the photosensitive member 1 of the cleaning blade 12 is desirably small in the initial stage. The smaller the surface roughness, the better the adhesion to the photosensitive member 1 and the less gap formation due to toner removal. . However, the frictional resistance with the photosensitive member 1 is increased, and the cleaning blade 12 vibrates as the photosensitive member 1 rotates, or the so-called stick-slip phenomenon in which the edge portion 13 is locally involved occurs. Troubles such as 12 “squeal” occur. Further, when the frictional resistance is large, the rotation of the photoreceptor 1 is inhibited. Usually, when the thickness is 10 μm or less, the edge portion 13 is crushed by the contact pressure, the degree of adhesion of the photosensitive member 1 is increased, and toner is not lost. However, if the surface roughness is further increased, the edge portion 13 is liable to be deteriorated due to rubbing with the photoconductor 1, and the surface property of the photoconductor 1 is also deteriorated accordingly. 1 Both lifespans are also shortened. In particular, when a substantially spherical polymer toner having an average circularity of about 0.97 or 0.99 is used, the surface roughness of the cleaning blade 12 also affects the surface. It is desirable to use a cleaning blade 12 having a roughness of 10 μm or less and 5 μm or more. Accordingly, it is not desirable to use a cleaning blade having a surface roughness of 20 μm or 30 μm. Using a blade processed so as to have a surface roughness of 10 μm or less leads to an improvement in image quality reliability.

  The positional relationship between the cleaning blade 12 and the photosensitive member 1 is not limited to the counter direction shown in FIG. 3, but may be the trailing direction shown in FIG.

  The cleaning blade 12 is effective with respect to the photosensitive member 1 both in the counter direction (see FIG. 3) and in the trailing direction (see FIG. 8). In any case, the contact pressure of the cleaning blade 12 with respect to the photoreceptor 1 is desirably 10 gf / cm or more and 25 gf / cm or less. Although the contact pressure is a factor that affects the cleaning performance, a low contact pressure is advantageous for preventing the edge portion 13 of the cleaning blade 12 from being damaged. Since the toner is easily affected, the toner is liable to be removed and the margin for the cleaning property is lowered. On the other hand, when the contact pressure is high, the surface roughness of the photosensitive member 1 and the edge portion 13 and the margin of cleaning with respect to attached foreign matter increase (easier cleaning), but the edge portion 13 is damaged. In addition, there is a problem that the life of the cleaning blade 12 and the photosensitive member 1 is shortened due to sliding abrasion on the photosensitive member 1. Therefore, it is preferable to reduce the contact pressure as much as possible as long as it does not interfere with toner cleaning. In the present invention, since the strain suppression plate 16 is provided, a good cleaning property can be achieved even if the strain suppression plate 16 is lighter than the conventional contact pressure. The fact that the weight can be reduced means that both the cleaning blade 12 and the photoreceptor 1 can have longer lifetimes than in the past. Therefore, it is desirable that the lower limit value of the contact pressure is 10 gf / cm and the upper limit value is 25 gf / cm. Of course, even if it is set to 25 gf / cm or more, it will not be immediately damaged and cannot be used. However, by using the strain suppression plate 16, it is not necessary to increase the contact pressure. Rather, since the same cleaning can be performed with the contact pressure equivalent to that of the conventional pulverized toner cleaning, the photosensitive member is more sensitive than the conventional one. The durability of the body 1 can be improved.

  About the shape of the front end side edge part 16a of the distortion suppression board 16, it is desirable to chamfer or to perform the taper-shaped cutting process as shown in FIG. If the strain suppression plate 16 is as thin as 0.5 mm or 1 mm, the tip side edge 16a may be chamfered and rounded, but if the strain suppression plate 16 is as thick as 2 mm or 3 mm, it is cut into a taper shape. Is preferred. By performing these chamfering and tapered cutting, it is possible to prevent the distortion suppressing plate 16 from coming into contact with the photosensitive member 1 and damaging the photosensitive member 1. Further, by performing chamfering or taper-shaped cutting, the leading edge 16a of the strain suppression plate 16 can be brought closer to the photoconductor 1, so that the cleaning blade 12 can be more reliably brought into contact with the photoconductor 1. It is possible to prevent the defective cleaning of the residual powder, and it is also effective for suppressing filming.

  As shown in FIG. 1, the cleaning brush 17 is disposed on the upstream side of the cleaning blade 12 along the rotation direction of the photoreceptor 1, and is driven to rotate about a center line parallel to the center line of the photoreceptor 1. The purpose of installing the cleaning brush 17 is auxiliary means (pre-cleaning) of the cleaning blade 12, so that a large amount of residual powder is not infiltrated into the cleaning blade 12 in advance before the cleaning blade 12. It is to eliminate the damage caused by the residual powder as much as possible.

  In addition, the adverse effect on the image quality (such as a decrease in resolution) is suppressed by scraping off contaminants such as discharge products, paper dust, and toner components adhering to the surface of the photoreceptor 1 by the rubbing force of the cleaning brush 17. Also do things.

  If the cleaning blade 12 has sufficient conditions for cleaning the residual powder on the photosensitive member 1, the cleaning brush 17 is not required. However, when image formation is performed over a long period of time, It is desirable to install it.

  When image formation is performed for a long time, the toner is gradually fixed to the edge portion 13 of the cleaning blade 12, and the fixed toner is sandwiched between the photosensitive member 1 and the edge portion 13, and the cleaning blade 12 and the photosensitive member 1. Or cleaning performance of residual powder such as toner is deteriorated. This sticking phenomenon occurs more frequently as the amount of toner transported to the cleaning blade 12 increases. That is, by reducing the amount of toner transported to the cleaning blade 12 by the cleaning brush 17, the burden on the cleaning blade 12 is reduced. This is to suppress the increase in frictional resistance.

  There are two types of cleaning brushes 17, straight hair brushes (cut pile brushes) and loop brushes. Most image forming apparatuses use straight hair brushes. In the case of a straight-hair brush, since the surface of the photoreceptor 1 is rubbed with the tip, there is a tendency that rubbing scratches enter. On the other hand, in the case of the loop brush, since it is rubbed on the surface of the fiber's belly (or back), there is an advantage that the photoconductor 1 is hardly scratched and has excellent cleaning properties. However, it is possible to alleviate the phenomenon of rubbing scratches on the photoreceptor 1 even with a straight hair brush by performing a process such as rounding the tip of the fiber of the straight hair brush.

  The loop brush includes an insulating brush and a conductive brush. In the present invention, a conductive brush is effective. Since the insulating brush takes time to discharge even if the brush itself is charged, even if the residual powder adheres, the separation from the brush is worsened. Therefore, the residual powder tends to accumulate in the cleaning device 7, and the cleaning efficiency is improved. It tends to cause deterioration of the image quality and background stains of the copy image quality. However, the conductively treated brush is easy to discharge even if the brush is charged, and the charge of the residual powder that has adhered is also discharged. The margin for copy image quality degradation due to 17 increases.

  The cleaning brush 17 is installed so as to be in surface contact (contact) with the photoreceptor 1 evenly. The amount of biting into the photoreceptor 1 is preferably 1 to 2 mm. Uneven installation causes uneven wear not only on the photoreceptor 1 but also on the tear brush. The rotation direction of the cleaning brush 17 may be either the counter direction or the trailing direction. However, it is desirable to rotate in the trailing direction when using the photoconductor 1 with high wear, and to rotate in the unter direction when using the photoconductor 1 with added filler to improve wear resistance. . This is because the hazard for the photosensitive member 1 is different between the counter installation and the trailing installation, and the wear force is less when installed in the trailing direction, and the wear force is higher in the counter direction. The rotation speed of the cleaning brush 17 is normally set between 150 and 300 rpm.

  The material of the loop brush used for cleaning includes nylon fiber, acrylic fiber, polyester fiber, carbon fiber, etc., and fiber manufacturers include Unitika, Toray, Kanebo, Kuraray, and Mitsubishi Rayon.

  The fiber diameter of the fiber used for the loop brush is 10 to 20 (D), the density is 24 to 48 filaments / 450 loops, and the length of the loop (fiber length) is 2 to 5 mm. D is denier and is represented by the weight of the yarn (g) × 9000 ÷ the length of the yarn (m). The smaller the value, the smaller the yarn diameter.

  The loop brush winds the fiber cut in a string shape spirally around the metal core without any gaps, and fixes the fiber so as not to be displaced. As a means for fixing, an adhesive, a double-sided pressure-sensitive adhesive tape, heat fusion, or the like is used. By adopting such a manufacturing method, it is possible to maintain a stable and non-uniform cleaning property without deviation. The manufacturing method is simple and can be performed in a short time. If a double-sided adhesive tape is used, the core bar can be easily reused.

  The loop brush is less likely to scratch the photoreceptor 1 than the straight brush. In general, the photoconductor 1 with low hardness is rubbed with the cleaning blade 12, the cleaning brush 17 and the developer to cause the surface of the photoconductor 1 to be rubbed to a greater or lesser extent. Since the cut surface of the fiber tip that rotates at a rotational speed of about 100 to 250 rpm hits the photoreceptor 1, scratches (fine scratches) are likely to occur compared to the loop brush, and abnormal images (white spots, The life of the photosensitive member 1 is shortened. In the case of a loop brush, since it rubs at the belly or back portion of the fiber, there is little occurrence of deep scratches, and in most cases it becomes a shallow uniform rubbing scratch.

  Loop brushes that can be suitably used in the present invention include acrylic fibers such as SA-7 (Toray Industries, Inc.), nylon beltlons ([nylon fiber, Kanebo, Type 931, 961, etc.), polyester beltrons [polyester fibers] Fiber, Kanebo, type B31, etc.].

As described above, the cleaning brush 17 is triboelectrically charged due to the rubbing with the photosensitive member 1, and the residual powder is likely to adhere to the cleaning brush 17. Therefore, it is desirable that the cleaning brush 17 is subjected to a conductive process. Conductive treatment is performed at the fiber manufacturing stage, and a method of filling the fiber with conductive carbon. When the resin is in a molten state, conductive carbon and fine metal particles such as tin, gold, and titanium are put into fibers. The In addition, after the fibers are formed, the conductive fibers and the fibers may be mixed. However, if the resistance is too low, there is a discharge from the photosensitive member 1 and an abnormal image is caused. Therefore, it is desirable that the resistance has a medium to high resistance of about 10 ⁵ to 10 ¹⁰ Ω · cm. Since SA-7 and Beltron are both electrically conductive and have a self-discharge capability even when charged, even if the toner is electrostatically adsorbed, it is removed from the cleaning brush 17 after copying is completed. I can do things. In the case of Veltron, conductive fine particles such as carbon are incorporated inside, and in SA-7, carbon is dispersed. The tendency for static elimination to be higher in Beltron than in SA-7 is seen. However, it takes several seconds to several tens of seconds for the electric charge to be sufficiently discharged. When the cleaning brush 17 is used, the brush and the core material (metal or conductively treated resin, etc.) are electrically coupled, and the core material It is desirable to ground the toner to the casing, or to apply a voltage that neutralizes the charge held by the toner and the photoreceptor. Since the polarity of the electric charge of the residual powder after transfer is not uniform (a mixture of positive and negative charges is mixed), it is necessary to fully grasp the situation and determine the voltage condition. May be better cleaned with grounding.

  In the case of polymerized toner, the polarity of the residual charge is relatively uniform even after transfer, and DC voltage can be applied, but AC voltage alone or a plus voltage is superimposed in consideration of variations in toner charging. Although it is desirable to apply the AC voltage, it may be better to ground (0V) without applying the voltage depending on the situation. The voltage condition example is set in the range of 50 to 2000 Hz, 300 to 1000 V, and the plus voltage is in the range of about 50 to 500 V. If the voltage is excessive, abnormal charging may occur and image noise may occur, so it is desirable to set it as low as possible.

  A second embodiment of the present invention will be described with reference to FIGS. The same portions as those described in FIGS. 1 to 9 are denoted by the same reference numerals, and description thereof is omitted (the same applies to the following embodiments).

  In the present embodiment, a damping material 21 is attached to the surface of the strain suppression plate 16. As a material of the damping material 21, a synthetic rubber having a high loss tangent (tan δ) is suitable, and examples thereof include a butyl rubber-based material. The loss tangent (tan δ) of butyl rubber is as high as about 0.3 to 1.0, but silicon rubber and chloroprene rubber are as low as about 0.05 to 0.1 and are not suitable as a material for a vibration damping material. Synthetic rubbers other than butyl rubber include honeynite and sorbosein (both are trade names), and the loss tangent (tan δ) is equal to or higher than that of butyl rubber. All of these have a track record as damping materials. The thicker the wall, the higher the damping effect. The wall thickness of a commercially available damping material is usually 1 mm or more. If it is 1 mm, 1 to 3 sheets are stacked and pasted together. Since butyl rubber, sorbosein, etc. have adhesiveness, it is desirable to cover them with polyester or Teflon film (Teflon is a registered trademark) to prevent adhesion and dust adhesion after being attached.

  Although the distortion suppression plate 16 can suppress the “squeal” of the cleaning blade 12 by itself, since the effect may not be obtained depending on the material and thickness of the distortion suppression plate 16, the vibration damping material 21 is distorted as an auxiliary member. Affix to the surface of the restraining plate 16. However, in order to suppress the vibration that causes “squealing” of the cleaning blade 12, even if the damping material 21 is thin, the effect can be seen. What is necessary is just to affix on the surface of 16 so that it may occupy 80% or more of the area, and a float may not arise. Usually, it is desirable to affix the damping material 21 having a thickness of about 2 mm.

  A third embodiment of the present invention will be described with reference to FIG. The printer, which is the image forming apparatus according to the present embodiment, includes a process cartridge 32 that includes the cleaning device 31 including the support 15, the cleaning blade 12, and the strain suppression plate 16 described in the above-described embodiments as one of the components. Have.

  The process cartridge 32 includes a cartridge case 33, the photosensitive member 1 accommodated and held rotatably around the center line in the cartridge case 33, the charging device 2, the developing device 4, and the cleaning device 31 accommodated in the cartridge case 33. It is configured.

  A recording medium container 8 is provided in the lower part of the main body case (not shown) of the printer, and the recording medium container 8 reaches the recording medium discharge unit 9 from which the recording medium S to which the toner image has been transferred is discharged. A recording medium conveyance path 10 is formed. In the middle of the recording medium conveyance path 10, a process cartridge 32, a transfer device 5, a fixing device 11 and the like are arranged. The process cartridge 32 is detachably attached to the main body case.

  In such a configuration, the image forming operation in the printer including the process cartridge 32 is performed in the same manner as the image forming operation in the printer of the first embodiment.

  By using the process cartridge 32 having the cleaning device 31 as a constituent member in this printer, various members disposed around the photoreceptor 1, for example, the charging device 2, the developing device 4, the cleaning device 31 and the like are broken down. Sometimes, the process cartridge 32 may be replaced as a whole, and maintenance performance is improved. In addition, by incorporating the cleaning device 31 into the process cartridge 32, the life of the photoconductor 1 is extended by improving the cleaning performance of the photoconductor 1 by the cleaning device 31, and as a result, the life of the process cartridge 32 is increased. .

  In this embodiment, the monochrome printer having one process cartridge 32 has been described as an example. However, in a tandem type color image forming apparatus having a plurality of image forming units for forming images of different colors. In each image forming unit, the process cartridge 32 including the cleaning device 31 described above can be used.

  Examples of the present invention will be described below.

<Example of Photoconductor for Evaluation>
An organic photoreceptor used for evaluation was prepared by the following procedure.

After dip coating with an undercoat layer (UL) coating solution having the following specifications, a JIS stipulated 3003 series aluminum alloy drum machined to φ30 mm, length 340 mm, and wall thickness 0.75 mm was used. Drying was carried out at 20 ° C. for 20 minutes to form an undercoat layer of about 3.5 μm.
Next, after dip-coating with a coating solution for charge generation layer (CGL) of the following specifications using a titanyl phthalocyanine-based charge generation material, it is dried by heating at 120 ° C. for 20 minutes to form a 0.2 μm charge generation layer. Formed.
Furthermore, after immersing in the charge transport layer (CTL) coating liquid of the following specifications using the charge transport material described in Chemical Formula 1 to coat the charge transport layer, heat drying at 130 ° C. for 20 minutes is performed. A charge transport layer (photosensitive layer) having an average film thickness of 28 μm was prepared.
A flange was attached to both ends of a conductive support in which an undercoat layer, a charge generation layer, and a charge transport layer were sequentially formed on the outer peripheral portion to complete a photoconductor for evaluation.
The average film thickness of the charge transport layer is an average value obtained by measuring 13 points at intervals of 20 mm starting from 50 mm from the end using an eddy current film thickness meter (type mms) manufactured by Fischer.

  Further, “parts” described below are parts by weight.

<Undercoat coating liquid>
Alkyd resin (Beckosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals) 6 parts Melamine resin (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals) 4 parts Titanium oxide (CR-EL Ishihara Sangyo) 40 parts Methyl ethyl ketone 200 parts

<Coating liquid for charge generation layer>
Oxotitanium phthalocyanine pigment (Ricoh) 2 parts Polyvinyl butyral (Union Carbide: XYHL) 0.2 parts Tetrahydrofuran (Kanto Chemical) 50 parts

<Coating liquid for charge transport layer>
Bisphenol Z-type polycarbonate (manufactured by Teijin Kasei Co., Ltd .: Z Polica Mv50,000) 10 parts Low molecular charge transport material of the following “Chemical 1” structure 8 parts Tetrahydrafuran 200 parts

<Example of manufacturing cleaning device>
Five types of polyurethane plate materials having a JIS-A hardness of 50 degrees, 58 degrees, 71 degrees, 80 degrees, and 86 degrees processed so that the surface roughness is 10 μm or less are 2 mm thick, 320 mm long, Cleaning blades cut to a width of 13 mm were prepared, and these cleaning blades had a width (free length; L2 in FIG. 2) from the edge on the front end side of the support to the edge contacting the photoconductor of 7 mm (to the support). Is attached to an L-shaped iron support having a plate thickness of 1 mm with a hot-melt adhesive so that the width is 6 mm.

  Hot melt so that a strip-shaped stainless steel plate (distortion suppression plate) having a width of 8 mm to 10 mm, a length of 320 mm, and a thickness of 0.4 mm is spaced 1 to 2 mm from the edge of the cleaning blade. A cleaning device as shown in FIG. 3 is produced by pasting with an adhesive.

  When a hard plastic material such as an acrylic plate is used instead of a stainless steel plate as the strain suppression plate, for example, the edge of the tip is tapered at an angle of about 20 degrees to form a knife edge shape of 320 mm × 11 mm A 2 mm acrylic plate was attached with a hot melt adhesive so that the space between the edge of the acrylic plate knife edge and the edge of the cleaning blade was 1 to 1.5 mm wide. A cleaning device as shown is produced.

<Production example of charging member>
The charging member for contact charging for charging the photoreceptor is 3 mm of epichlorohydrin rubber in which carbon is uniformly dispersed in a 6 mm brass rod rod and the electric resistance is adjusted to 6 × 10 ⁵ Ω · cm (when 100 VDC is applied). It is coated and polished so as to have a thickness of 5%, and carbon, silica, and fluororesin are dispersed in the epichlorohydrin rubber on the layer, and the electric resistance becomes (3-5) × 10 ⁸ Ω · cm (when 100 VDC is applied). The epichlorohydrin rubber thus prepared was uniformly applied to a thickness of 1 mm and processed into a size of φ14 mm × 314 mm (effective charging width: 312 mm).

<Examples 1-4>
As an evaluation machine for confirming the effect, an IMAGIO MF2200 modified machine (manufactured by Ricoh) was used. As the cleaning blade, one made of polyurethane rubber (manufactured by Bando Chemical Co., Ltd.) with a surface roughness of 10 μm or less prepared by cutting it into a strip of 320 mm × 13 mm × 2 mm is prepared. An L-shaped support made of iron and having a thickness of 1 mm was attached so that the free length “L2” of the cleaning blade was 7 mm. Further, a 320 mm × 10 mm × 0.4 mm stainless steel plate (distortion suppression plate) is attached to the other surface of the cleaning blade so that the free length “L1” to the edge portion is 2 mm (Examples 1 to 3). A 320 mm × 8 mm × 0.4 mm stainless steel plate (strain suppressing plate) was attached so that the free length to the edge of the cleaning blade was 2 mm (Example 4). A hot-melt adhesive (for example, Asahi Chemical Co., Ltd. Asahi Melt, Balloon Melt, etc.) was used to attach the stainless steel plate (strain suppressing plate) to the cleaning blade. In these Examples 1 to 4, no vibration damping material was attached to the cleaning blade. The contact pressure when the cleaning blade was brought into contact with the photosensitive member was set to be about 22 gf / cm.

  The cleaning device of Examples 1 to 4, the photoconductor for evaluation (initial friction coefficient is 0.35 to 0.43), and the charging device are sequentially mounted on the process cartridge dedicated to the evaluation machine, and the developer has an average particle size. A substantially spherical polymer toner having an average circularity of about 0.97 having a mean particle size of about 6.3 μm and a carrier having an average particle diameter of about 55 μm was mixed at a ratio of 5% by weight. The toner used was a lubricant (zinc stearate fine particles) added in an amount of 0.025% by weight based on the toner weight.

  When mounting the photoconductor, it was confirmed that polyvinylidene fluoride (PVdF) powder was applied to the edge of the cleaning blade and the toner used was applied to the surface of the photoconductor, and that the photoconductor was sufficiently rotated.

  Attach the process cartridge to the evaluation machine, set the charging potential to -800V, set the image area potential to -150V, and set the development bias potential to -650V. Paper evaluation was carried out. As a test chart used for the evaluation, a Ricoh original A-3 version test chart to which a resolution evaluation chart (JIS Z 6008 1982, manufactured by Kodak) was attached was used.

  The evaluation items are the evaluation of the cleaning property of the photosensitive member surface after taking out the process cartridge, the halftone image (2-dot pattern) on the A-3 plate test chart, and the background of the copy image or using a 4 × magnifier. Evaluation of background contamination, confirmation of occurrence of cleaning blade squeal (key sound) during operation, measurement of friction coefficient after evaluation of paper passing, and evaluation of abrasion amount of photosensitive layer. The results are shown in Table 1.

  From the results shown in Table 1, when the hardness of the cleaning blade was 58 degrees (Example 1), slightly fractionated powder was observed on the photoreceptor, and background contamination was confirmed. In other examples, the background stain could not be confirmed. Therefore, this value (58 degrees) is estimated as a limit level for rubber hardness. The edge of the cleaning blade is crushed due to the low hardness, and the adhesion to the photoconductor is improved, but the frictional resistance is increased, which causes distortion of the edge of the cleaning blade and entrainment of polymerized toner, It seems to have caused dirt and density unevenness.

  On the other hand, there is no “squealing” of the cleaning blade, the friction coefficient of the photosensitive layer and the wear amount of the photosensitive layer show good values, and it is estimated that the durability of the photosensitive member is sufficient.

  In the case of the cleaning blade having a cleaning blade hardness of 71 degrees and 80 degrees (Examples 2 to 4), the cleaning performance is good when the ratio of the strain suppression plate to the width of the cleaning blade is 77% or 61%. The cleaning blade “squealing” and the amount of wear on the photosensitive layer were small and appropriate settings. After the evaluation, the cleaning blade was removed, and using an ultra-deep shape measuring microscope (VK-8500 manufactured by Keyence Corporation), it was confirmed whether or not the edge of the cleaning blade contacted with the photosensitive member was defective. Several of them were confirmed to be about 40 μm, but most of the others were around 20-30 μm, and it was confirmed that they still have sufficient durability. When the friction coefficient is in the range of 0.3 to 0.35, even if the edge portion has a defect with a depth of 50 to 60 μm, the depth of the edge portion is within the friction coefficient range of 0.15 to 0.25. It has been separately confirmed that the cleaning property of the polymerized toner is good even if there is a defect of 70 μm.

<Comparative Examples 1-6>
As an evaluation machine for confirming the effect, the same IMAGIO MF2200 modified machine (manufactured by Ricoh) as in Examples 1 to 5 described above was used. A cleaning blade made of polyurethane rubber (manufactured by Bando Chemical Co., Ltd.) cut into a strip shape of 320 mm × 13 mm × 2 mm is prepared, and an L-shaped support made of iron and having a thickness of 1 mm on one surface of the cleaning blade. Was pasted so that the free length “L2” of the cleaning blade was 7 mm. However, the cleaning blade had a JIS-A hardness of 50 degrees (Comparative Example 1), 58 degrees (Comparative Example 2), 71 degrees (Comparative Examples 3 and 6), 80 degrees (Comparative Example 4), and 86 degrees (Comparative). Example 5). None of these cleaning blades were provided with damping material.

  The cleaning device of Comparative Examples 1 to 6, the photoconductor for evaluation, and the charging device are sequentially attached to the process cartridge dedicated to the evaluation machine, and the developer has an average particle diameter of 6.3 μm and an average circularity of about 0.97. A substantially spherical polymer toner mixed with a carrier having an average particle diameter of about 55 μm at a ratio of 5% by weight was used. For Comparative Examples 1 to 5, a developer in which 0.02% by weight of zinc stearate fine particles were added relative to the developer weight was used as a developer, and for Comparative Example 6, a developer to which no zinc stearate was added. It was used.

  Attach the process cartridge to the evaluator, set the charging potential to -800V, the image area potential to -150V, the development bias potential to -650V, and target 50,000 sheets in an environment of 23-25 ° C and 58-62% RH A paper evaluation was conducted. Evaluation items were the same as those in Examples 1 to 4. The results are shown in Table 2.

  From the results in Table 2, when the polymerization toner was used without attaching the strain suppression plate, there was a difference in the number of cleaning defects, but eventually the cleaning defect occurred. Regarding Comparative Examples 1 to 5 in which the friction coefficient was in the range of 0.3 to 0.4, cleaning failure gradually occurred, and background contamination was confirmed on the copy. On the other hand, when a developer to which zinc stearate is not added is used, the coefficient of friction reaches 0.6 to 0.63 after 20 sheets, and thereafter changes within that range, and 50 sheets have elapsed. 0.62 was shown (Comparative Example 6). In this example, there was already a sign of poor cleaning on the second sheet, and since there was no tendency to improve thereafter, evaluation was stopped at 50 sheets.

  Although all the photoconductors were rubbed and scratched on the surface of the photoconductor, it was not judged to be a scratch that, on average, was a shallow flaw of about 1.3 μm that would affect cleaning failure. The cleaning failure was caused by a friction coefficient of 0.3 to 0.4 at which cleaning failure cannot occur with the pulverized toner, but it seems that the polymerization toner has a slightly high value, and there is no distortion suppression plate. There is a possibility that the edge of the cleaning blade may be bent (stick-slip phenomenon) due to the overlap of the long free length of 7 mm.

  Microscopic observation of the edge portion of the cleaning blade was close to the results of Examples 1 to 5, and most of the defects had a depth of 30 μm. Since the edge portion is pushed by the photosensitive member and the defect is crushed, it is numerically determined that a cleaning failure cannot occur.

<Examples 5-7>
As an evaluation machine for confirming the effect, an Imagio MF2200 remodeling machine (manufactured by Ricoh) was used in the same manner as in the above-described Examples and Comparative Examples. As the cleaning blade, one having a JIS-A hardness of 71 degrees and 80 degrees and made of polyurethane rubber (manufactured by Bando Chemical Co., Ltd.) cut into a strip shape of 320 mm × 13 mm × 2 mm is prepared. An L-shaped support made of iron and having a thickness of 1 mm was attached to one surface so that the free length “L2” of the cleaning blade was 7 mm. Furthermore, a 320 mm × 11 mm × 2 mm acrylic plate (distortion suppression plate), which is tapered at an angle of 20 degrees on the tip side edge on the other surface of the cleaning blade, has a free length to the edge of the cleaning blade. L1 ″ was pasted so as to be within a width of 1 to 1.5 mm. The contact pressure when the cleaning blade was brought into contact with the photosensitive member was set to about 20 gf / cm.

  The cleaning device of Examples 5 to 7, the photoconductor for evaluation (initial friction coefficient is 0.35 to 0.43), and the charging device are sequentially mounted on the process cartridge dedicated to the evaluation machine, and the developer has an average particle size. A substantially spherical polymer toner having an average circularity of about 0.97 having a mean particle size of about 6.3 μm and a carrier having an average particle diameter of about 55 μm was mixed at a ratio of 5% by weight. The toner was prepared by adding 0.02% by weight of lubricant (zinc stearate fine particles) to the toner weight (Examples 5 and 6) and using no lubricant (Example 7). .

  When mounting the photoconductor, it was confirmed that polyvinylidene fluoride (PVdF) powder was applied to the edge of the cleaning blade and the toner used was applied to the surface of the photoconductor, and that the photoconductor was sufficiently rotated.

  Attach the process cartridge to the evaluator, set the charging potential to -800V, the image area potential to -150V, the development bias potential to -650V, and target 50,000 sheets in an environment of 23-25 ° C and 58-62% RH A paper evaluation was conducted. Evaluation items were the same as those in Examples 1 to 4 and Comparative Examples 1 to 6. The results are shown in Table 3.

  From the results shown in Table 3, the width “L1” from the edge portion of the strain suppression plate to the edge portion of the cleaning blade was set to 1 mm, and the friction coefficient was as low as about 0.34. No halftone image density uniformity, no cleaning blade “squeal”, and the like were good results (Examples 5 and 6). However, when the friction coefficient is as high as 0.6, even if “L1” is 1 mm, “squealing” of the cleaning blade occurs (Example 7), and a slight distortion occurs at the edge of the cleaning blade. In addition, toner omission occurred and cleaning was poor. In order to improve the cleaning performance, it seems that the reduction of the coefficient of friction of the photoreceptor is an essential condition. In the observation of the blade edge defect, there were few large defect portions in Examples 5 and 6, and 20-30 μm was the center.

<Comparative Examples 7-9>
As an evaluation machine for confirming the effect, the same IMAGIO MF2200 remodeling machine (manufactured by Ricoh) as in the above-described Examples and Comparative Examples was used. The cleaning blade is made of polyurethane rubber (manufactured by Bando Chemical Co., Ltd.) having a JIS-A hardness of 71 degrees (Comparative Example 7) and 80 degrees (Comparative Examples 8 and 9) cut into strips of 320 mm × 13 mm × 2 mm. Prepare an L-shaped support made of iron and having a thickness of 1 mm on one side of this cleaning blade, the width of the surface to be attached to the cleaning blade is 9 mm, and the free length “L2” of the cleaning bleed is 4 mm Pasted to be. Further, a 320 mm × 9 mm × 0.4 mm or 320 mm × 8 mm × 0.4 mm distortion suppression plate was attached to the other surface of the cleaning blade so that the free length “L1” of the cleaning blade was 4 mm or 5 mm. . The contact pressure of the cleaning blade against the photosensitive member was set to 20 gf / cm. None of these cleaning blades is provided with a damping material.

  The cleaning device of Comparative Examples 7 to 9, the photoconductor for evaluation, and the charging device are sequentially attached to the process cartridge dedicated to the evaluation machine, and the developer has an average particle diameter of 6.3 μm and an average circularity of about 0.97. A substantially spherical polymer toner mixed with a carrier having an average particle diameter of about 55 μm at a ratio of 5% by weight was used. The developer used was zinc stearate fine particles added in an amount of 0.02% by weight based on the developer weight.

  The process cartridge was mounted on an evaluation machine, and the charging potential was set to -800 V, the image portion potential was set to -150 V, and the developing bias potential was set to -650 V, and paper passing evaluation was performed with a target of 50,000 sheets. Evaluation items were the same as those in the above-described Examples and Comparative Examples. The results are shown in Table 4.

  From the results shown in Table 4, the occupied width of the strain suppression plate with respect to the cleaning blade is 60% or more, and there is no problem as an attached width, and the free length “L2” of the cleaning blade attached to the support surface is 4 mm. As a result, the strength of the cleaning blade was improved, but as a result, it was insufficient. In all cases, poor cleaning occurred, and the halftone image was dull and the background was stained (slightly lightly stained). It was. This is presumably because the effect of the strain suppression plate was not exhibited by setting the width “L1” from the strain suppression plate to the photoreceptor to 4 mm or 5 mm. After the evaluation, a thin film-like filming phenomenon due to toner adhesion was observed on the photoreceptor.

  On the other hand, a slight occurrence of “squealing” of the cleaning blade was observed, but it did not feel uncomfortable and was in a practically acceptable range. The reason for the small “squeal” of the cleaning blade seems to be due to the relatively low coefficient of friction (around 0.4). Regarding the defect of the edge portion of the cleaning blade, the level of 30 μm was slightly higher, similar to Examples 5-7.

<Examples 8 to 11>
As an evaluation machine for confirming the effect, the same IMAGIO MF2200 remodeling machine (manufactured by Ricoh) as in the above-described Examples and Comparative Examples was used. A cleaning blade made of polyurethane rubber (manufactured by Bando Chemical Co., Ltd.) having a JIS-A hardness of 71 degrees and cut into 320 mm × 13 mm × 2 mm strips is prepared, and one side of this cleaning blade is made of iron. The L-shaped support having a thickness of 1 mm was pasted so that the free length “L2” was 7 mm. Furthermore, a 320 mm × 10 mm × 0.4 mm stainless steel plate (distortion suppression plate) was attached to the other surface of the cleaning blade so that the free length “L1” to the edge portion was 2 mm. The contact pressure when the cleaning blade was brought into contact with the photosensitive member was set to be about 22 gf / cm.

  The cleaning device of Examples 8 to 11, the photoconductor for evaluation (initial friction coefficient is 0.3 to 0.4), and the charging device are sequentially mounted on the process cartridge dedicated to the evaluation machine, and the developer has an average particle size. A substantially spherical polymer toner having an average circularity of about 0.97 having a mean particle size of about 6.3 μm and a carrier having an average particle diameter of about 55 μm was mixed at a ratio of 5% by weight. Four types of toner were prepared by adding a lubricant (zinc stearate fine particles) in an amount of 0.04 wt% to 0.01 wt% with respect to the toner weight. Example 8 is 0.04% by weight, Example 9 is 0.025% by weight, Example 10 is 0.015% by weight, and Example 11 is 0.01% by weight.

  When mounting the photoreceptor, it was confirmed that polyvinylidene fluoride (PVdF) powder was applied to the edge of the cleaning blade and toner to be used was applied to the surface of the photoreceptor, and that the photoreceptor was sufficiently rotated.

  Attach the process cartridge to the evaluator, set the charging potential to -800V, the image area potential to -150V, the development bias potential to -650V, and target 50,000 sheets in an environment of 23-25 ° C and 58-62% RH A paper evaluation was conducted. Evaluation items were the same as those in the above Examples and Comparative Examples. The results are shown in Table 5.

  From the results in Table 5, the friction coefficient of the photoconductor depends on the amount of lubricant, and the more the lubricant adhered to the photoconductor, the lower the friction coefficient. As the friction coefficient is lowered, the load on the contact pressure of the cleaning blade is apparently reduced, so that the damage received by the blade edge is reduced and the life can be extended.

  However, as in Example 8, when the friction coefficient is lowered to about 0.15, the polymerized toner enters between the edge portion and the photosensitive member, causing a slight cleaning failure, and also improving the image quality. Impact will come out. On the other hand, as shown in Example 11, when the effect of the lubricant is not present and the friction coefficient exceeds 0.5, the edge portion of the cleaning blade is distorted and a stick-slip phenomenon occurs even if a strain suppression plate is provided. As a result, poor cleaning occurs.

  According to Table 5, a cleaning failure was confirmed when the friction coefficient was as low as 0.15 or as high as 0.52. However, the cleaning blade did not “squeal”. There was no problem when the friction coefficient was 0.25 or 0.36. From this, it is considered that if the friction coefficient is in the range of 0.20 or more and 0.5 or less, almost good cleaning properties can be obtained.

<Examples 12 to 13>
As an evaluation machine for confirming the effect, the same IMAGIO MF2200 remodeling machine (manufactured by Ricoh) as in the above-described Examples and Comparative Examples was used. A cleaning blade made of polyurethane rubber (manufactured by Bando Chemical Co., Ltd.) having a JIS-A hardness of 71 degrees and cut into 320 mm × 13 mm × 2 mm strips is prepared, and one side of this cleaning blade is made of iron. The L-shaped support having a thickness of 1 mm was pasted so that the free length “L2” was 7 mm. Furthermore, on the other surface of the cleaning blade, a 320 mm × 6 mm × 0.4 mm stainless steel strain suppression plate (Example 12) or 320 mm × 6 mm so that the free length “L1” to the edge is 2 mm. A 7 mm × 0.4 mm stainless steel strain suppression plate (Example 13) was attached. The contact pressure when the cleaning blade was brought into contact with the photosensitive member was set to be about 22 gf / cm.

  The cleaning device of Examples 12 to 13, the photosensitive member for evaluation (initial friction coefficient is 0.4), and the charging device are sequentially attached to the process cartridge dedicated to the evaluation machine, and the developer has an average particle size of 6.3 μm, A substantially spherical polymer toner having an average circularity of about 0.97 was mixed with a carrier having an average particle diameter of about 55 μm at a ratio of 5% by weight. The toner used was a lubricant (zinc stearate fine particles) added in an amount of 0.02% by weight based on the toner weight.

  In mounting the photoconductor, polyvinylidene fluoride (PVdF) powder was applied to the edge of the cleaning blade and the toner used was applied to the surface of the photoconductor, and it was confirmed that the photoconductor was sufficiently rotated.

  Attach the process cartridge to the evaluator, set the charging potential to -800V, the image area potential to -150V, the development bias potential to -650V, and target 50,000 sheets in an environment of 23-25 ° C, 58-62% RH A paper evaluation was conducted. Evaluation items were the same as those in the above Examples and Comparative Examples. The results are shown in Table 6.

  From the results of Table 6, it was considered that when the width of the distortion suppression plate attached to the cleaning blade was 54%, the entire cleaning blade was slightly insufficient in strength, but the cleaning property was confirmed to be good. However, some unevenness was observed in the halftone image, and a slight amount of background stain was observed only after confirmation with a 10 × magnifier. However, 61% of the examples had no practical problem at all. That is, the strain suppression width needs to be at least 54%.

1 is a schematic side view showing a printer which is an image forming apparatus according to a first embodiment of the present invention. It is a perspective view which shows a part of cleaning apparatus. It is the vertical side view. It is sectional drawing which shows the structure of a photoreceptor. It is sectional drawing which shows the modification of a photoreceptor. It is a vertical side view which shows the modification of a cleaning apparatus. It is a vertical side view which shows the other modification of a cleaning apparatus. It is a vertical side view which shows the other modification of a cleaning apparatus. It is a vertical side view which shows the other modification of a cleaning apparatus. It is a perspective view which shows a part of cleaning apparatus of the 2nd Embodiment of this invention. It is the vertical side view. It is a schematic side view which shows the printer which is an image forming apparatus of the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photosensitive member 2 Charging apparatus 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 7 Cleaning apparatus 12 Cleaning blade 13 Edge part 15 Support body 15a Front end side edge part 16 Distortion suppression plate 16a Front end side edge part 16b Rear end side edge part 21 Damping material 31 Cleaning device 32 Process cartridge

Claims (14)

A rectangular cleaning blade having an edge portion in contact with the outer peripheral surface of the electrophotographic photosensitive member;
A support that is in contact with one surface of the cleaning blade and supports the cleaning blade;
A strain suppression plate that is in contact with the other surface of the cleaning blade and sandwiches the cleaning blade with the support,
The length dimension “L1” from the tip of the edge of the cleaning blade to the tip side edge of the distortion suppression plate is the length from the tip of the edge of the cleaning blade to the tip side edge of the support. The cleaning device is set to “L1 <L2” with respect to the dimension “L2”.   When the edge portion of the cleaning blade is brought into contact with the outer peripheral surface of the electrophotographic photosensitive member, the distortion suppressing plate is located on the downstream side along the moving direction of the electrophotographic photosensitive member. The cleaning device according to claim 1, wherein the strain suppression plate and the support are positioned so that the support is positioned on the upstream side in the body movement direction.   The cleaning device according to claim 1 or 2, wherein the length dimension "L1" is 1 to 2 mm and the length dimension "L2" is 3 to 8 mm.   The cleaning device according to claim 1, wherein the strain suppression plate is formed of a metal material.   The cleaning device according to claim 1, wherein the strain suppression plate is formed of a hard plastic material.   The cleaning device according to claim 1, wherein a width dimension of the distortion suppression plate from the front end side edge part to the rear end side edge part is 92 to 54% with respect to the width dimension of the cleaning blade. .   The cleaning device according to claim 1, wherein a vibration damping material is attached to a surface of the strain suppression plate.   The cleaning device according to any one of claims 1 to 7, wherein a chamfering process or a tapered cutting process is applied to the edge portion on the front end side of the distortion suppressing plate.   The cleaning device according to claim 1, wherein the cleaning blade is made of polyurethane rubber and has a JIS-A hardness of 58 to 85 degrees.   9. The cleaning device according to claim 1, wherein a contact pressure of the cleaning blade to the outer peripheral surface of the electrophotographic photosensitive member is 10 to 25 gf / cm.   The cleaning device according to claim 1, wherein a surface roughness of the edge portion of the cleaning blade is 10 μm or less. An electrophotographic photoreceptor having a toner image formed on the outer peripheral surface;
A cartridge case for rotatably holding the electrophotographic photosensitive member;
The cleaning device according to any one of claims 1 to 11, wherein the cleaning device is held in the cartridge case and is disposed opposite to an outer peripheral surface of the electrophotographic photosensitive member.
A process cartridge comprising: An electrophotographic photoreceptor having a toner image formed on the outer peripheral surface;
A charging device for uniformly charging the outer peripheral surface of the electrophotographic photosensitive member;
An exposure device that writes an electrostatic latent image on the outer peripheral surface of the uniformly charged electrophotographic photosensitive member;
A developing device that develops an electrostatic latent image written on the outer peripheral surface of the electrophotographic photosensitive member to form a toner image;
A transfer device for transferring the developed toner image to a recording medium;
The cleaning device according to any one of claims 1 to 11, wherein the cleaning device is disposed opposite to an outer peripheral surface of the electrophotographic photosensitive member;
An image forming apparatus comprising: A recording medium conveyance path provided in the apparatus main body and extending from the recording medium storage unit to the recording medium discharge unit;
The process cartridge according to claim 12, wherein the process cartridge is detachably disposed in the middle of the recording medium conveyance path;
An image forming apparatus comprising:

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