JP2018054956A - Cleaning blade and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning blade that can reduce the occurrence of chipping of the blade due to concentration of stress, while reducing the occurrence of passing of a residual toner at the ends of the cleaning blade and turn-up of the blade, and an image forming apparatus.SOLUTION: A cleaning blade comprises: an edge part 31 that is in contact with a photoconductor drum 51; and end faces 32 that are provided at both ends in a direction along the edge part 31 and continue to the edge part 31. The end faces 32 each include, in at least partial area including an area on the edge part 31, a blade end hardened part 34 having a higher Young's modulus on its surface than that inside in the depth direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cleaning blade for cleaning toner remaining on the surface of an image carrier for forming an image on a recording material by an electrophotographic method or an electrostatic recording method, and an image forming apparatus using the same.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus has been widely applied as a copying machine, a printer, a plotter, a facsimile, and a multifunction machine having a plurality of these functions. This type of image forming apparatus develops an electrostatic image formed on a photoreceptor using a developer (two-component developer) mainly composed of toner (non-magnetic) and carrier (magnetic). Widely used. Even after the toner image formed on the surface of the photoreceptor is transferred to the transfer material or intermediate transfer body, or after the toner image is transferred from the intermediate transfer body to the transfer material, the surface of the photoreceptor or intermediate transfer body Part of the toner tends to remain. Therefore, it is necessary to remove the toner remaining on the surface of the photosensitive member or the intermediate transfer member, and this removal is usually performed by a cleaning blade. The cleaning blade has a thickness of 1 mm or more and 3 mm or less, for example, and the length of the surface facing the object to be cleaned (photosensitive drum, intermediate transfer member, etc.) in the longitudinal direction is longer than the thickness. Shape) is used.

  For example, the cleaning blade is attached to a metal holder and fixed for use in the image forming apparatus. For example, the cleaning blade is installed such that the edge portion (tip ridge line portion) is in contact with the object to be cleaned. For the cleaning blade, urethane rubber is often used because of its excellent wear resistance and permanent distortion. Further, a toner having a small particle size and a high sphericity is known as a toner developed to meet the recent demand for higher image quality. This small particle size and high sphericity toner is characterized by a relatively high transfer efficiency and can meet the demand for higher image quality.

  However, a toner having a small particle size and high sphericity has a problem that even if an attempt is made to remove the toner from the surface of the object to be cleaned using a cleaning blade, it is difficult to remove the toner sufficiently and a cleaning failure may occur. ing. This is because a toner having a small particle size and a high sphericity is more likely to pass through a slight gap formed between the cleaning blade and the object to be cleaned than a toner other than that. In order to suppress such toner slipping, it is effective to increase the contact pressure between the cleaning blade and the object to be cleaned to reduce the gap.

  However, as the contact pressure between the cleaning blade and the cleaning object increases, the frictional force between the cleaning blade and the cleaning object tends to increase. As the frictional force between the cleaning blade and the object to be cleaned increases, the cleaning blade is more likely to be pulled in the direction of movement of the surface of the object to be cleaned, which may cause a problem of so-called blade curling that causes the cleaning blade to bend. .

  Normally, the development area on the photoreceptor is an image area, but a small amount of scattered toner may adhere to the photoreceptor outside the development area. In order to reduce the adhesion of the scattered toner as much as possible, the charging area is wide at both ends of the non-image area so that it is difficult to electrically attract the toner. However, even with such a configuration, it is difficult to eliminate toner adhesion, so the cleaning blade that contacts the photoreceptor is sufficiently long to include the charged area of the image area. It is common to be able to perform a range of cleanings.

  In the case of the above configuration, the amount of toner or external additive reaching the cleaning blade is smaller in the non-image area than in the image area. The toner and the external additive have an effect of maintaining the sliding property between the cleaning blade and the photoreceptor. On the other hand, in the charging region, when the photosensitive member is discharged by the charging device, a discharge product adheres to the surface of the photosensitive member, thereby reducing the slipping property between the cleaning blade and the photosensitive member. Therefore, both ends of the cleaning blade in the charging area and the image area tend to have excessive frictional force with the photosensitive member, and the blade is liable to be bent. In addition, since both ends of the cleaning blade are freely supported, even if the slipperiness of the photosensitive member is the same, the blade tends to bend more easily than the central portion. In order to prevent this edge blade from curling, a technology has been developed that impregnates both ends of a urethane rubber cleaning blade with an isocyanate compound to increase the hardness of both ends compared to the center. Reference 1). In this cleaning blade, both ends of the tip surface along the edge are impregnated with an isocyanate compound, thereby increasing the hardness of both ends and suppressing occurrence of blade curl.

JP 2010-170157 A

  However, in the cleaning blade described in Patent Document 1 described above, since both ends of the tip surface along the edge portion are impregnated with an isocyanate compound, the cured portions at both ends are swollen. For this reason, a step occurs at the boundary between the cured portion and the non-cured portion on the front end surface along the edge portion, and the boundary portion does not follow the surface of the object to be cleaned, and toner slippage may occur at the boundary portion. There was sex. Further, since the behavior of the cured portion and the non-cured portion is different when they are in contact with the object to be cleaned, there is a possibility that stress concentrates at the boundary portion and the cleaning blade is chipped at the boundary portion.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning blade and an image forming apparatus capable of suppressing the occurrence of blade chipping due to stress concentration while suppressing the occurrence of residual toner slippage and blade curl at the end of the cleaning blade.

  The cleaning blade of the present invention includes an edge portion that comes into contact with an object to be cleaned, and end surfaces that are provided at both ends in a direction along the edge portion and are continuous with the edge portion, and the end surface includes the edge portion. The first high Young's modulus part having a higher Young's modulus on the surface than the inside in the depth direction is provided in at least a part of the region including the region on the first side.

  According to the present invention, the end face of the cleaning blade has the first high Young's modulus portion whose surface has a Young's modulus higher than that in the depth direction in at least a part of the region including the region on the edge portion side. For this reason, it is possible to suppress the occurrence of blade chipping due to stress concentration while suppressing the occurrence of residual toner slippage and blade curl at the end of the cleaning blade.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment. 1 is a perspective view illustrating a schematic configuration of a cleaning blade of an image forming apparatus according to an embodiment. 6 is a graph showing the relationship between the distance from the end face of the cleaning blade of the image forming apparatus according to the embodiment and the Young's modulus. It is a perspective view which shows schematic structure of the cleaning blade of the image forming apparatus which concerns on other embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In the present embodiment, a tandem type full color printer is described as an example of the image forming apparatus 1. However, the present invention is not limited to the tandem type image forming apparatus 1, and may be an image forming apparatus of another type, and is not limited to a full color, and may be a monochrome or a mono color. Alternatively, the present invention can be implemented for various uses such as a printer, various printing machines, a copying machine, a FAX, and a multifunction machine.

  As shown in FIG. 1, the image forming apparatus 1 includes an apparatus main body 10, a sheet feeding unit (not shown), an image forming unit 40, a sheet discharge unit (not shown), and a control unit 11. The image forming apparatus 1 can form a four-color full-color image on a recording material in response to an image signal from an unillustrated document reading device, a host device such as a personal computer, or an external device such as a digital camera or a smartphone. . Note that the sheet S as a recording material is formed with a toner image, and specific examples include plain paper, a synthetic resin sheet that is a substitute for plain paper, cardboard, and an overhead projector sheet.

  The image forming unit 40 can form an image on the sheet S fed from the sheet feeding unit based on the image information. The image forming unit 40 includes image forming units 50y, 50m, 50c, and 50k, toner bottles 41y, 41m, 41c, and 41k, exposure devices 42y, 42m, 42c, and 42k, an intermediate transfer unit 44, and a secondary transfer unit. 45 and a fixing unit 46. The image forming apparatus 1 according to the present embodiment is compatible with full color, and the image forming units 50y, 50m, 50c, and 50k are yellow (y), magenta (m), cyan (c), black ( Each of the four colors k) is provided separately with the same configuration. For this reason, in FIG. 1, each of the four color components is shown with the same symbol followed by a color identifier. However, in the specification, there may be a case where only the symbol is used without adding the color identifier.

The image forming unit 50 includes a photosensitive drum (image carrier) 51 that carries and moves a toner image, a charging roller 52, a developing device 20, a pre-exposure device 54, and a cleaning blade 30. . The image forming unit 50 is unitized as a process cartridge and is configured to be detachable from the apparatus main body 10. In this embodiment, a negatively charged toner having an average particle diameter of 5.5 μm is used as the toner, and a magnetic carrier having a saturation magnetization of 0.205 Am ² / m ³ and an average particle diameter of 35 μm is used as the carrier. Further, toner and carrier mixed at a weight ratio of 6:94 are used as a developer.

  The photosensitive drum 51 is rotatable and carries an electrostatic image used for image formation. In the present embodiment, the photosensitive drum 51 is a negatively charged organic photoconductor (OPC) having an outer diameter of 30 mm, and is rotated by a motor (not shown) in the direction of the arrow at a process speed (peripheral speed) of, for example, 200 mm / sec. Driven. The photosensitive drum 51 has an aluminum cylinder as a base, and has three layers of an undercoat layer, a photocharge generation layer, and a charge transport layer, which are sequentially applied and laminated as a surface layer on the surface thereof.

  The charging roller 52 is, for example, a rubber roller that has a length of 320 mm, contacts the surface of the photosensitive drum 51, and rotates by being driven, and uniformly charges the surface of the photosensitive drum 51. A charging bias power source is connected to the charging roller 52. The charging bias power source applies a DC voltage as a charging bias to the charging roller 52 and charges the photosensitive drum 51 through the charging roller 52.

  The exposure device 42 is a laser scanner, and emits laser light according to the separated color image information output from the control unit 11. The exposure device 42 can form an image having a length of 305 mm in the longitudinal direction. The developing device 20 develops the electrostatic image formed on the photosensitive drum 51 with toner by applying a developing bias.

  The developing device 20 has a developing sleeve 24. The developing device 20 stores a developer and develops the electrostatic image formed on the photosensitive drum 51. The developing sleeve 24 carries a developer having non-magnetic toner and a magnetic carrier and transports the developer to a developing area facing the photosensitive drum 51. The developing sleeve 24 coats the developer in the range of 310 mm in the longitudinal direction. The developing sleeve 24 is made of a nonmagnetic material such as aluminum or nonmagnetic stainless steel, and is made of aluminum in the present embodiment. Inside the developing sleeve 24, a roller-shaped magnet roller is fixedly installed in a non-rotating state with respect to the developing container.

  The toner image developed on the photosensitive drum 51 is primarily transferred to the intermediate transfer unit 44. The surface of the photosensitive drum 51 after the primary transfer is neutralized by the pre-exposure device 54. The cleaning blade 30 is of a counter blade type and is in contact with the photosensitive drum 51 with a predetermined pressing force. After the primary transfer, the toner remaining on the photosensitive drum 51 without being transferred to the intermediate transfer unit 44 is removed by the cleaning blade 30 provided in contact with the photosensitive drum 51 to prepare for the next image forming process. Details of the cleaning blade 30 will be described later.

  The intermediate transfer unit 44 includes a plurality of rollers such as a driving roller 44a, a driven roller 44d, and primary transfer rollers (transfer means) 47y, 47m, 47c, and 47k, and an intermediate transfer that is wound around these rollers and carries a toner image. Belt 44b. The primary transfer rollers 47y, 47m, 47c, and 47k are arranged to face the photosensitive drums 51y, 51m, 51c, and 51k, abut against the intermediate transfer belt 44b, and the toner image on the photosensitive drum 51 is separated by another image carrier. Primary transfer is performed on an intermediate transfer belt 44b.

  The intermediate transfer belt 44b is in contact with the photosensitive drum 51 to form a primary transfer portion with the photosensitive drum 51, and a primary transfer bias is applied to transfer the toner image formed on the photosensitive drum 51 to the primary transfer portion. First transfer. By applying a positive primary transfer bias to the intermediate transfer belt 44b by the primary transfer roller 47, the respective negative toner images on the photosensitive drum 51 are sequentially transferred to the intermediate transfer belt 44b.

  The secondary transfer unit 45 includes a secondary transfer inner roller 45a and a secondary transfer outer roller 45b. A full-color toner image formed on the intermediate transfer belt 44b is transferred onto the sheet S by applying a positive secondary transfer bias to the secondary transfer outer roller 45b. The secondary transfer outer roller 45b is in contact with the intermediate transfer belt 44b to form a secondary transfer portion 45 with the intermediate transfer belt 44b, and a secondary transfer bias is applied to the primary transfer belt 44b. The transferred toner image is secondarily transferred to the sheet S by the secondary transfer unit 45.

  The fixing unit 46 includes a fixing roller 46a and a pressure roller 46b. When the sheet S is nipped and conveyed between the fixing roller 46a and the pressure roller 46b, the toner image transferred to the sheet S is heated and pressurized and fixed to the sheet S. The sheet discharge unit feeds the sheet S conveyed from the discharge path after fixing, for example, discharges it from a discharge port and stacks it on a discharge tray.

  The control unit 11 is configured by a computer, and includes, for example, a CPU, a ROM that stores a program for controlling each unit, a RAM that temporarily stores data, and an input / output circuit that inputs and outputs signals to and from the outside. The CPU is a microprocessor that controls the entire control of the image forming apparatus 1 and is the main body of the system controller. The CPU is connected to the sheet feeding unit, the image forming unit 40, and the sheet discharging unit via an input / output circuit, and exchanges signals with each unit and controls operations. The ROM stores an image formation control sequence for forming an image on the sheet S and the like.

  Next, an image forming operation in the image forming apparatus 1 configured as described above will be described.

  When the image forming operation is started, first, the photosensitive drum 51 is rotated and the surface is charged by the charging roller 52. Then, laser light is emitted from the exposure device 42 to the photosensitive drum 51 based on the image information, and an electrostatic latent image is formed on the surface of the photosensitive drum 51. When toner adheres to the electrostatic latent image, it is developed and visualized as a toner image, and transferred to the intermediate transfer belt 44b.

  On the other hand, the sheet S is supplied in parallel with the toner image forming operation, and the sheet S is conveyed to the secondary transfer unit 45 via the conveyance path in synchronization with the toner image on the intermediate transfer belt 44b. . Further, the image is transferred from the intermediate transfer belt 44b to the sheet S, and the sheet S is conveyed to the fixing unit 46, where an unfixed toner image is heated and pressed to be fixed on the surface of the sheet S. Discharged from.

  Next, the cleaning blade 30 in the image forming apparatus 1 of the present embodiment will be described in detail.

  As shown in FIG. 2, the cleaning blade 30 has a substantially rectangular plate shape, and includes an edge portion 31 that contacts the photosensitive drum 51 that is a cleaning target, an end surface 32, and a facing surface 33. The edge portion 31 is one side along the longitudinal direction of the cleaning blade 30 and is located at the rotation center of the photosensitive drum 51 so as to be in the counter direction with respect to the rotation direction of the photosensitive drum 51 (moving direction indicated by an arrow in the drawing). Abutted along. The end surfaces 32 are provided at both end portions in the width direction W that is a direction along the edge portion 31 of the cleaning blade 30, that is, in a direction intersecting the rotation direction of the photosensitive drum 51, and are provided continuously to the edge portion 31. Yes. The facing surface 33 includes the edge portion 31, faces the surface of the photosensitive drum 51, and continues to the end surface 32.

  Here, the cleaning blade 30 tends to cause blade curling at both end abutting portions 31 a located at both ends in the width direction W of the edge portion 31. In order to suppress blade curling, it is conceivable to increase the Young's modulus of the surface of the both-end contact portion 31a. However, when the Young's modulus changes abruptly in the width direction W, stress concentration occurs at that site. As a result of intensive studies by the inventors of the present application, it was found that the chipping of the cleaning blade 30 is likely to occur at a location where stress acting on the cleaning blade 30 is concentrated. Furthermore, at the both ends of the cleaning blade 30 in the width direction W, the surface of the both-end contact portion 31a is reduced in friction by appropriately controlling the Young's modulus of the surface of the both-end contact portion 31a with the photosensitive drum 51. I found out.

  As a method for increasing the Young's modulus of the both-end contact portion 31a of the urethane rubber cleaning blade 30, it is effective to control the molecular structure of the urethane rubber in the both-end contact portion 31a. The urethane rubber can be synthesized using, for example, a polyisocyanate, a polyol, a chain extender (for example, a polyfunctional polyol), and a urethane rubber synthesis catalyst. When the urethane rubber is a polyester-based urethane rubber, a polyester-based polyol may be used as the polyol in order to synthesize the polyester-based urethane rubber. When the polyester urethane rubber is an aliphatic polyester urethane rubber, an aliphatic polyester polyol may be used as the polyol in order to synthesize the aliphatic polyester urethane rubber.

  More specific methods for increasing the Young's modulus of the both end contact portions 31a of the urethane rubber cleaning blade 30 include a method of changing the degree of crosslinking of the urethane rubber or controlling the molecular weight of the raw material of the urethane rubber. Further, as a suitable method, there is a method of increasing the concentration of the isocyanurate group by adding an isocyanurate group to the urethane rubber. An isocyanurate group can be contained in urethane rubber as a group derived from polyisocyanate which is a raw material of urethane rubber.

  In the present embodiment, the cleaning blade 30 is preferably a urethane rubber cleaning blade 30 containing an isocyanurate group from the viewpoint of easy control of the Young's modulus of the surface of the both-end contact portion 31a. In that case, in order to increase the Young's modulus of the surface of the both-end contact portion 31a of the cleaning blade 30, the content of the isocyanurate group is increased on the surface (and the vicinity thereof) of the urethane rubber in the both-end contact portion 31a. Is preferred.

  In the present embodiment, the end surface 32 of the cleaning blade 30 is formed in at least a part of the region including the region on the edge portion 31 side, and the blade end hardened portion (the first hardened portion) having a higher surface Young's modulus than the inside in the depth direction. High Young's modulus part) 34. The blade end hardening part 34 includes an edge part 31. In the present embodiment, the cleaning blade 30 has a thickness of 2 mm in the Y direction, a length of 20 mm in the X direction, and a width of 345 mm in the width direction W. The blade end hardening portion 34 is directed from the edge portion 31 side in the X direction. The length is 2 mm.

In the present embodiment, by setting the Young's modulus Y ₀ of the surface of the blade end hardening portion 34 of the cleaning blade 30 to 100 MPa (about 10 mgf / μm ² ) or more, the surface of the both-end contact portion 31a of the cleaning blade 30 can be reduced. Friction can be achieved. Further, the both end contact portions 31a of the cleaning blade 30 are not easily deformed. The reason why the surface of the blade end hardened portion 34 of the cleaning blade 30 can be reduced in friction is that there are few microscopic contact points (true contact areas) involved in the friction between the cleaning blade 30 and the photosensitive drum 51. It is thought to be. By reducing the friction of the surface of the blade end hardened portion 34 of the cleaning blade 30 and making the both-end contact portions 31a of the cleaning blade 30 difficult to deform, curling of the edge portion 31 of the cleaning blade 30 is suppressed. Is done.

Further, if the Young's modulus of the surface of the cleaning blade 30 is low, the cleaning blade 30 easily follows the shape of the toner, but if the Young's modulus is too high, it becomes difficult to follow the shape of the toner. If it becomes difficult to follow the shape of the toner, the surface of the cleaning blade 30 is pushed not only in the toner portion but also in the peripheral portion of the toner, so that the toner easily slips through the void around the toner. Accordingly, the Young's modulus Y ₀ of the surface of the both end contact portion 31a of the cleaning blade 30 of the present embodiment is 4000 MPa (about 400 mgf / μm ² ) or less, preferably 3440 MPa or less, and 2500 MPa or less. It is more preferable.

  From the above, the Young's modulus of the surface of the blade end hardened portion 34 of the cleaning blade 30 of the present embodiment is in the range of 100 MPa to 4000 MPa, preferably in the range of 100 MPa to 3440 MPa. More preferably, it is the range of 100 MPa or more and 2500 MPa or less. In the present embodiment, the cleaning blade 30 is configured to increase the Young's modulus of the surface of the both-end contact portion 31a and to decrease the Young's modulus from the surface of the blade end hardened portion 34 toward the inside in the width direction W. Has been.

Specifically, as shown in FIG. 3, the ratio Y ₅₀ / Y ₀ between the Young's modulus Y _{50 at} a position 50 μm inside from the surface of the blade end hardened portion 34 of the cleaning blade 30 and the Young's modulus Y _{0 of the} surface is 0. .5 or less (preferably 0.2 or less). Thereby, even if the surface Young's modulus of the blade end hardened portion 34 is increased to some extent, good followability to unevenness / foreign matter can be obtained. Further, by setting the ratio Y ₅₀ / Y ₀ to 0.5 or less, it becomes easy to maintain a large cleaning angle, and a high toner damming ability can be obtained.

The average change rate of Young's modulus from the surface of the blade end hardened portion 34 to the position inside 20 μm is configured to be equal to or higher than the average change rate of Young's modulus from the position inside 20 μm to the position inside 50 μm. The average rate of change of Young's modulus from the surface of the blade end hardened portion 34 to the position inside 20 μm is Y ( ₂₀ ) when the Young's modulus inside the blade end hardened portion 34 of the cleaning blade 30 is 20 μm inside. Y ₀ -Y ₂₀ ) / Y ₀ } / (20-0). Further, the average change rate of Young's modulus from the position inside 20 μm to the position inside 50 μm is represented by {(Y ₂₀ −Y ₅₀ ) / Y0} / (50-20). As a result, the stress is dispersed in the width direction of the cleaning blade 30, and the cleaning blade 30 is less likely to be chipped.

Hereinafter, the average change rate {(Y ₀ -Y ₂₀ ) / Y ₀ } / (20-0) of the Young's modulus from the surface of the both-end contact portion 31a to the position inside 20 μm is also expressed as “ΔY _0-20 ”. . Moreover, the average change rate {(Y ₂₀ −Y ₅₀ ) / Y ₀ } / (50-20) of Young's modulus from the position inside 20 μm to the position inside 50 μm is also expressed as “ΔY _20-50 ”. If expressed using these, the cleaning blade 30 of the present embodiment is configured to satisfy ΔY _0-20 ≧ ΔY _20-50 . Thereby, even if the Young's modulus decreases rapidly from the surface of the blade end hardened portion 34 to the inside (inside 50 μm from the surface), the cleaning blade 30 is not easily chipped. Further, the followability to the irregularities on the surface of the photosensitive drum 51 is also improved.

  As shown in FIG. 2, the blade end hardened portion 34 has regions of an outermost portion 34a, an intermediate portion 34b, and a deepest portion 34c from the surface to the inside, and is formed so that the Young's modulus decreases stepwise. Has been. The load that deforms the blade end curing portion 34 of the cleaning blade 30 is a stress in a direction along the facing surface 33 of the cleaning blade 30 facing the photosensitive drum 51. Here, for convenience of explanation, the case where the Young's modulus changes stepwise is described, but the present invention is not limited to this, and the change of the Young's modulus of the cleaning blade 30 may be continuous. It is preferable that the change in the Young's modulus of the blade end hardened portion 34 of the cleaning blade 30 is continuous rather than stepwise. In this case, the blade end hardening portion 34 has a gradient of Young's modulus that continuously increases from the inside toward the surface (see FIG. 3). The term “continuous” means that there is no interface between portions having different Young's moduli that are liable to cause peeling or chipping, so that peeling or chipping of the cleaning blade 30 can be suppressed.

  Examples of the method of supporting the cleaning blade 30 include a method of bonding the cleaning blade 30 to a metal support member, a method of sandwiching the cleaning blade 30 with a plurality of support members, and the like. Other methods for supporting the cleaning blade 30 include, for example, a method in which the cleaning blade 30 is formed at the tip of a support member, that is, a method in which a part of the cleaning blade 30 is used as a support portion.

  The cleaning blade 30 of the present embodiment is a urethane rubber cleaning blade 30. Among urethane rubbers, polyester urethane rubber is preferred from the viewpoint of mechanical strength such as wear resistance and difficulty of permanent deformation due to contact pressure (creep resistance), and among them, aliphatic polyester urethane rubber Is more preferable.

  As a method for controlling the Young's modulus of the blade end hardened portion 34 of the cleaning blade 30 as described above, it is effective to control the molecular structure of the urethane rubber. The urethane rubber can be synthesized using, for example, a polyisocyanate, a high molecular weight polyol, a chain extender (for example, a polyfunctional low molecular weight polyol), and a urethane rubber synthesis catalyst. In order to synthesize the polyester-based urethane rubber, a polyester-based polyol may be used as the polyol. In order to synthesize the aliphatic polyester-based urethane rubber, an aliphatic polyester-based polyol may be used as the polyol.

  As a method for controlling the Young's modulus of the blade end hardening portion 34 of the cleaning blade 30 made of urethane rubber as described above, specifically, the degree of crosslinking of the urethane rubber is changed, the molecular weight of the raw material of the urethane rubber is changed. The method of controlling is mentioned. Among these methods, a method in which the concentration of isocyanurate groups derived from polyisocyanate, which is a raw material of urethane rubber, is increased toward the surface side of the urethane rubber is preferable from the viewpoint of accuracy in controlling Young's modulus.

  Examples of the polyisocyanate include 4,4′-diphenylmethane diisocyanate (MDI, 4,4′-MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2, 6-TDI). Moreover, xylene diisocyanate (XDI), 1,5-naphthylene diisocyanate (1,5-NDI), p-phenylene diisocyanate (PPDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI) are mentioned. Further, 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylene diisocyanate (TMXDI), carbodiimide-modified MDI, polymethylene polyphenyl isocyanate (PAPI) and the like can be mentioned. Among these, 4,4'-diphenylmethane diisocyanate is preferable.

  Examples of the high molecular weight polyol (aliphatic polyester-based polyol) include ethylene butylene adipate polyester polyol and butylene adipate polyester polyol. Moreover, a hexylene adipate polyester polyol, a lactone-type polyester polyol, etc. are mentioned. Moreover, you may mix and use these. Of these aliphatic polyester-based polyols, butylene adipate polyester polyol and hexylene adipate polyester polyol are preferable in terms of high crystallinity. The higher the crystallinity of the aliphatic polyester polyol, the higher the hardness of the resulting polyester urethane rubber (cleaning blade made of polyester urethane rubber), and the durability of the cleaning blade 30 can be enhanced.

  The number average molecular weight of the high molecular weight polyol is preferably 1500 or more and 4000 or less, and more preferably 2000 or more and 3500 or less. The higher the number average molecular weight of the polyol, the higher the hardness, elastic modulus and tensile strength of the resulting urethane rubber (urethane rubber cleaning blade). Further, the smaller the number average molecular weight, the lower the viscosity and the easier the handling.

  Examples of the chain extender (polyfunctional low molecular weight polyol) include glycol. Examples of the glycol include ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), and 1,4-butanediol (1,4-BD). Further, 1,6-hexanediol (1,6-HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylylene glycol (terephthalyl alcohol), triethylene glycol, and the like can be given. Examples of chain extenders other than glycol include trihydric or higher polyhydric alcohols. Examples of the trihydric or higher polyhydric alcohol include trimethylolpropane, glycerin, pentaerythritol, sorbitol, and the like. Moreover, you may mix and use these.

  Urethane rubber synthesis catalysts are roughly classified into urethanization catalysts (reaction promotion catalysts) for promoting rubberization (resinization) and foaming, and isocyanurate formation catalysts (isocyanate trimerization catalysts). In the present invention, these may be mixed and used.

  Examples of the urethanization catalyst include tin-based urethanization catalysts such as dibutyltin dilaurate and stannous octoate, triethylenediamine, tetramethylguanidine, pentamethyldiethylenetriamine, and dimethylimidazole. Further, amine-based urethanization catalysts such as tetramethylpropanediamine and N, N, N′-trimethylaminoethylethanolamine can be used. In the present invention, these may be mixed and used. Among these urethanization catalysts, triethylenediamine is preferable in that the urethane reaction is particularly accelerated.

  Examples of the isocyanuration catalyst include metal oxides such as Li2O and (Bu3Sn) 2O, hydride compounds such as NaBH4, and alkoxide compounds such as NaOCH3, KO- (t-Bu), and borate. . Further, amine compounds such as N (C2H5) 3, N (CH3) 2CH2C2H5, and N2C6H12, HCO2Na, CO3 (Na) 2, PhCO2Na / DMF, CH3CO2K, and (CH3CO2) 2Ca can be given. Moreover, alkaline carboxylate salt compounds, such as alkali soap and a naphthenate, alkaline formate compound, quaternary ammonium salt compounds, such as ((R1) 3-NR2OH) -OOCR3, etc. are mentioned. Examples of the combined catalyst (co-catalyst) used as the isocyanurate-forming catalyst include amine / epoxide, amine / carboxylic acid, and amine / alkylene imide. In the present invention, these may be mixed and used.

  Among the urethane rubber synthesis catalysts, N, N, N'-trimethylaminoethylethanolamine, which exhibits an action of an isocyanurate catalyst in addition to an action as a urethanization catalyst alone, is preferable. Moreover, additives, such as a pigment, a plasticizer, a waterproofing agent, antioxidant, a ultraviolet absorber, a light stabilizer, can also be used together as needed.

  Next, a method for controlling the distribution of isocyanurate groups as described above by synthesizing urethane rubber in this embodiment will be described. That is, an aliphatic polyester-based polyol is used as a polyol, an isocyanurate-forming catalyst is applied to the inner surface of a mold, and a raw material in which the ratio of polyisocyanate and aliphatic polyester-based polyol is within a specific range is put in this mold, This is a method of synthesizing rubber.

  By applying the isocyanurate forming catalyst to the inner surface of the mold into which the raw material is put, the isocyanurate forming reaction is promoted particularly in the portion in contact with the inner surface of the mold. Therefore, it is preferable to use excess polyisocyanate with respect to the aliphatic polyester-based polyol. Furthermore, the isocyanurate-forming catalyst applied to the inner surface of the mold and the temperature of the mold act on the excess polyisocyanate to synthesize urethane rubber whose distribution of isocyanurate groups is controlled as described above. Is done.

  The use amount (number of moles) of the aliphatic polyester-based polyol with respect to the polyisocyanate is preferably 30 mol% or more and 40 mol% or less with respect to the number of moles of the polyisocyanate. The smaller the aliphatic polyester polyol, the more easily the effect of excess polyisocyanate is obtained, and the Young's modulus of the surface of the blade end cured portion 34 of the cleaning blade 30 can be easily controlled to 100 MPa or more. On the other hand, by suppressing the excess of polyisocyanate to some extent, it becomes easy to control the Young's modulus of the surface of the blade end cured portion 34 of the cleaning blade 30 to 4000 MPa or less.

  The mold temperature is preferably in the range of 80 ° C. or higher and 150 ° C. or lower, and more preferably in the range of 100 ° C. or higher and 130 ° C. or lower. In order to synthesize the urethane rubber by reacting the raw materials in the mold, the temperature of the mold is preferably high to some extent from the viewpoint of the reaction speed. However, as the temperature of the mold increases, the blade end hardening portion 34 is increased. There is a tendency that the difference in Young's modulus between the surface and the inside becomes small.

  As a method for manufacturing the cleaning blade 30, in addition to the above-described method, for example, a method in which a liquid is poured into a drum-shaped mold and a centrifugal force is applied (centrifugal method), or a belt or groove-shaped mold is used. And a method of casting the solution into a mold (cast press method). In the present embodiment, the cleaning blade 30 is arranged in a counter direction with respect to the rotation direction of the photosensitive drum 51 during image formation (the movement direction of the surface of the photosensitive drum 51) as a contact method with the photosensitive drum 51. This is adopted as a counter method. However, the present invention is not limited to this, and it is also possible to employ a with method in which the photosensitive drum 51 is disposed in the width direction with respect to the rotation direction of the photosensitive drum 51 during image formation (the movement direction of the surface of the photosensitive drum 51).

  Next, a method for manufacturing the cleaning blade 30 will be described. In the following, “part” means “part by mass”.

(Step of obtaining the first composition)
299 parts of 4,4′-diphenylmethane diisocyanate (hereinafter also referred to as “4,4′-MDI”) and 767.5 parts of butylene adipate polyester polyol (hereinafter also referred to as “BA2600”) having a number average molecular weight of 2600 are 80. The mixture was reacted at 0 ° C. for 3 hours to obtain a first composition (prepolymer) containing 7.2% by mass of NCO groups.

(Step of obtaining the second composition)
N, N, N′-trimethylaminoethylethanolamine (hereinafter also referred to as “ETA”) as a urethane rubber synthesis catalyst in 300 parts of hexylene adipate polyester polyol (hereinafter also referred to as “HA2000”) having a number average molecular weight of 2000 ) 0.25 part was added and stirred at 60 ° C. for 1 hour to obtain a second composition.

(Step of obtaining a mixture)
The first composition is heated to 80 ° C., the second composition heated to 60 ° C. is added thereto, and the mixture is stirred and mixed with the first composition and the second composition. Got. The number of moles of polyol in this mixture was 17 mol% based on the number of moles of polyisocyanate in the mixture. Hereinafter, this ratio is also expressed as “M (OH / NCO)”. In this example, M (OH / NCO) = 17 mol%.

(Process to obtain a cleaning blade made of urethane rubber)
A catalyst solution prepared by mixing 100 parts of ethanol with 100 parts of ethanol was spray-applied to one place on the inner surface of a mold for manufacturing a cleaning blade. Thereafter, the catalyst solution was wiped on a part of the inner surface of the mold with a urethane rubber blade. Although only one side of the end portion is shown in the drawing, the other surface is similarly processed. Then, after heating the mold to 110 ° C., a mold release agent is applied to the inner surface of the mold where the catalyst solution is not applied, and the mold is heated again to 110 ° C. and stable at that temperature. I let you. Thereafter, the mixture was injected into the mold (inside the cavity). After the injection, it was heated at 110 ° C. (molding temperature) for 30 minutes to cause a curing reaction, and then demolded to obtain a urethane rubber plate. The obtained urethane rubber plate was cut with a cutting machine to form an edge portion 31 minutes to obtain a cleaning blade 30 made of urethane rubber. The obtained cleaning blade 30 had a thickness of 2 mm in the Y direction, a length of 20 mm in the X direction, and a width of 345 mm in the width direction W.

  Next, the operation of the cleaning blade 30 of the present embodiment will be described. When the image forming process is started and the photosensitive drum 51 rotates, the developed toner image is primarily transferred to the intermediate transfer belt 44b. After the primary transfer, the toner remaining on the photosensitive drum 51 without being transferred to the intermediate transfer unit 44 is removed by the cleaning blade 30. At this time, since the blade end hardened portion 34 is formed and hardened at both ends of the cleaning blade 30 in the width direction W, occurrence of blade curling at the both end contact portions 31a of the edge portion 31 can be suppressed. As a result, the toner is prevented from slipping between the cleaning blade 30 and the photosensitive drum 51, and the occurrence of defective cleaning is prevented.

  As described above, according to the image forming apparatus 1 of the present embodiment, the end surface 32 of the cleaning blade 30 is at least part of the area including the area on the edge portion 31 side, and the surface of the cleaning blade 30 is more than the inside in the depth direction. The blade end hardened portion 34 has a high Young's modulus. For this reason, it is possible to suppress the occurrence of chipping of the cleaning blade 30 due to stress concentration while suppressing the occurrence of residual toner slippage and blade curl at the end of the cleaning blade 30.

  In the cleaning blade 30 of the present embodiment described above, the blade end hardening portion 34 is formed with a length of 2 mm from the edge portion 31 side in the X direction, but is not limited thereto. For example, the length may be 4 mm from the edge portion 31 side in the X direction. In the present embodiment, the cleaning blade 30 has a thickness of 2 mm in the Y direction, a length of 20 mm in the X direction, and a width of 345 mm in the width direction W. In this case, for example, the blade end curing portion 34 is on the edge portion 31 side. It is preferable that the length is 2 to 4 mm from the X direction to the X direction.

In the cleaning blade 30 of the present embodiment described above, the blade end hardened portion 34, which is a portion having a high Young's modulus, is formed only on the end face 32. However, the present invention is not limited to this, for example, as shown in FIG. The surface 33 may be provided with a portion having a high Young's modulus. In this case, the facing surface 33 has a facing surface hardened portion (second high Young's modulus portion) 35 having a surface Young's modulus higher than that in the depth direction in at least a part of the region including the region on the edge portion 31 side. Have In the present embodiment, the facing surface curing portion 35 includes an edge portion 31. The facing surface hardened portion 35 has a gradient of Young's modulus that continuously increases from the inside toward the surface. Further, the Young's modulus of the surface of the facing surface cured portion 35 is Y ₀ , the Young's modulus at a position inside 20 μm from the facing surface cured portion 35 is Y ₂₀ , and the Young's modulus at a position inside 50 μm from the facing surface cured portion 35 is Y ₅₀ . The following relationship is satisfied. The operation and effect of the facing surface curing portion 35 are the same as those of the blade end curing portion 34.
100 MPa ≦ Y ₀ ≦ 4000 MPa
Y ₅₀ / Y ₀ ≦ 0.5
{(Y ₂₀ -Y ₅₀ ) / Y ₀ } / (50-20) ≦ {(Y ₀ -Y ₂₀ ) / Y ₀ } / (20-0)

Example 1
The Young's modulus was evaluated using the cleaning blade 30 of the above-described embodiment. First, a method for measuring Young's modulus will be described. The Young's modulus of the cleaning blade 30 was measured using a microindentation hardness tester ENT-1100 (trade name) manufactured by Elionix Corporation. At appropriate points from the surface of the blade end hardened portion 34 of the cleaning blade 30 toward the inside, a load-unloading test was performed under the following conditions, and Young's modulus was obtained as a calculation result of the testing machine.
Test mode: Load-unloading test Load range: A
Test load: 100 [mgf]
Number of divisions: 1000 [times]
Step interval: 10 [msec]
Load holding time: 2 [seconds]

  First, the cleaning blade 30 was cut at both end portions 2 mm in the width direction. And the measurement and calculation which were mentioned above were performed in the direction which goes to the inside from the end surface 32 about the center location of the thickness direction Y of the cleaning blade 30 thickness. Specifically, from the surface of the end face 32 to the inside, the above-described measurement and calculation were performed at positions of 2 μm from the surface to 60 μm, 10 μm from 60 μm to 100 μm, and 20 μm from 100 μm to 300 μm. Here, the measurement and the result are obtained by averaging the measured values of the two ends at each measurement position, where x μm is the distance from the surface of the end face 32 in the direction of the arrow in the lower diagram of FIG. Used as the rate Yx. Note that the surface of the end face 32 was x = 0. The results are shown in Table 1.

  Next, an evaluation method for the cleaning blade 30 will be described. Three types of photosensitive drums having the same size as the photosensitive drum 51 of the image forming apparatus 1 and different surface shapes were prepared. These are a photosensitive drum (circumferential streak) having Sm 30 μm and uneven height 2 μm in the circumferential direction formed on the surface, and a photosensitive drum (recessed part) having a recess 40 μm in diameter and 2.5 μm in depth with an area ratio of 50%. And a photosensitive drum (smooth) having a smooth surface. These were respectively mounted on the Bk station of the image forming apparatus 1 described above. For each photosensitive drum 51, the cleaning blade 30 obtained as described above was installed such that the edge portion 31 abuts on the photosensitive drum 51.

  The installation conditions were a set angle of 22 °, a contact pressure of 28 gf / cm, and a free length of 8 mm. Then, in a high-temperature and high-humidity environment of 30 ° C./80% RH, a durability test of 10,000 sheets was performed at a discharge current of 100 μA without developing, and the dripping was evaluated. The evaluation results are shown in Table 2. In Table 2, when a wrinkle occurred within 10,000 sheets, it was marked as x, and when a wrinkle did not occur, it was marked as ◯.

  In the cleaning blade 30 in Example 1, the smooth photosensitive drum was wrinkled, but the other photosensitive drums were not wrinkled, and it was recognized as a practical level.

(Example 2)
In Example 1, the blade end hardened portion 34 was formed by changing the range of application of the catalyst on the inner surface of the mold from the edge portion 31 of the end surface 32 to 4 mm. Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, the smooth photosensitive drum was wrinkled, but the other photosensitive drums were not wrinkled, and it was recognized as a practical level.

(Example 3)
In Example 1, as shown in FIG. 4, in addition to the blade end hardening part 34 in the range of 2 mm from the edge part 31 of the end face 32, the surface on which the catalyst on the inner surface of the mold is applied is the same as in Example 1. The facing surface cured portion 35 was also formed by applying to the facing surface 33. Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, no wrinkling occurred on all the photosensitive drums, and it was recognized as a practical level.

Example 4
In Example 1, the blade end hardened portion 34 was formed by changing the range of application of the catalyst on the inner surface of the mold to the entire end surface 32. Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, curling occurred on the concave photosensitive drum and the smooth photosensitive drum, but no curling occurred on the circumferential streaked photosensitive drum, which was recognized as a practical level. With respect to the concave photosensitive drum and the smooth photosensitive drum, since the entire end face 32 is cured, an excessive load is applied to both ends in the width direction of the cleaning blade, and a sufficient effect cannot be obtained.

(Example 5)
In Example 1, the blade end hardened portion 34 was formed by changing the range of application of the catalyst on the inner surface of the mold from the edge portion 31 of the end face 32 to 1 mm. Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, curling occurred on the concave photosensitive drum and the smooth photosensitive drum, but no curling occurred on the circumferential streaked photosensitive drum, which was recognized as a practical level. With respect to the concave photosensitive drum and the smooth photosensitive drum, when the blade end curing portion 34 was 1 mm from the edge portion 31, a sufficient effect on the curling could not be obtained.

(Comparative Example 1)
In Example 1, a cleaning blade was produced in the same manner as in Example 1 except that the catalyst was not applied to the inner surface of the mold, and the sag was evaluated. The evaluation results are shown in Table 2. As shown in Table 2, it was confirmed that wrinkles occurred on all the photosensitive drums and did not reach a practical level.

(Comparative Example 2)
In Example 1, the surface on which the catalyst was applied on the inner surface of the mold was the facing surface 33, and the facing surface curing portion 35 was formed on the facing surface 33. Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, no wrinkle occurred on all the photosensitive drums. However, the edge portion 31 of the cleaning blade after the test was worn, and the surface having a low Young's modulus inside the cleaning blade was the edge portion 31. Therefore, as the durability of the cleaning blade progresses, the Young's modulus of the edge portion of the cleaning blade decreases. When used for a long time, it is confirmed that there is a possibility that wrinkles occur at both ends in the width direction of the cleaning blade, and it does not reach a practical level.

(Comparative Example 3)
In Example 1, the range in which the catalyst on the inner surface of the mold was applied was set to a range of 2 mm on both ends of the facing surface 33 (2 mm inward from the end surface 32). Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, the result of the dripping was the same as in Examples 1 and 2, but the blade chipping occurred at the boundary between the cured portion and the non-cured portion in the edge portion 31. This is considered to be because a portion where the Young's modulus changes suddenly on the surface of the facing surface 33 and stress concentrates on the portion, and it was confirmed that it did not reach a practical level.

(Comparative Example 4)
In Example 1, the range in which the catalyst on the inner surface of the mold was applied was set to a range of 2 mm on both ends of the tip surface (2 mm on the inside from the end surface 32). Other than that, a cleaning blade was produced in the same manner as in Example 1, and Young's modulus was measured, and the sag was evaluated. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, the result of the dripping was the same as in Examples 1 and 2, but blade chipping occurred at the boundary between the hardened portion and the non-hardened portion at the contact edge. As in Comparative Example 3, it is considered that a portion where the Young's modulus changes rapidly on the surface of the second surface and stress is concentrated on that portion, and it is confirmed that the practical level is not reached. It was.

(Comparative Example 5)
In Example 1, a cleaning blade was produced in the same manner as in Example 1 except that the catalyst solution was not applied to the inner surface of the mold. Next, 4,4′-MDI heated to 80 ° C. was dropped into a range of 2 mm at both ends (2 mm inward from the end surface 32) of the tip surface of the manufactured cleaning blade. Then, 4,4′-MDI adhering to the surface of the cleaning blade after 30 minutes was wiped off with ethanol. Then, it was left in a high humidity environment of 25 ° C./90% RH for 2 days to hydrolyze 4,4′-MDI soaked in the surface of the cleaning blade. did. Tables 1 and 2 show the Young's modulus measurement results and evaluation results, respectively. As shown in Table 2, the result of the dripping was the same as in Examples 1 and 2, but blade chipping occurred at the boundary between the hardened portion and the non-hardened portion at the contact edge. This is because Comparative Example 5 employs the same processing method as that of Patent Document 1 described above, and similarly to Comparative Example 3, a portion where the Young's modulus changes abruptly on the surface of the second surface is formed, and stress is applied to that portion. It was thought that this was because of the concentration, and it was confirmed that it did not reach the practical level.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 30 ... Cleaning blade, 31 ... Edge part, 32 ... End surface, 33 ... Opposing surface, 34 ... Blade end hardening part (1st high Young's modulus part), 35 ... Opposing surface hardening part (2nd 47, 47y, 47m, 47c, 47k ... primary transfer roller (transfer means), 51, 51c, 51k, 51m, 51y ... photosensitive drum (object to be cleaned, image carrier).

Claims (15)

An edge portion that comes into contact with an object to be cleaned, and an end surface that is provided at both ends in a direction along the edge portion and continues to the edge portion,
The end face has a first high Young's modulus portion whose surface Young's modulus is higher than that in the depth direction in at least a part of the region including the region on the edge portion side,
A cleaning blade characterized by that. The first high Young's modulus part includes the edge part,
The cleaning blade according to claim 1. The first high Young's modulus part has a gradient of Young's modulus that continuously increases from the inside toward the surface.
The cleaning blade according to claim 1 or 2, wherein The Young's modulus of the first surface of the high Young's modulus unit when the Y _0,
100 MPa ≦ Y ₀ ≦ 4000 MPa
Satisfy the relationship
The cleaning blade according to any one of claims 1 to 3, wherein When the Young's modulus of the surface of the first high Young's modulus part is Y ₀ , and the Young's modulus at a position inside 50 μm from the first high Young's modulus part is Y ₅₀ ,
Y ₅₀ / Y ₀ ≦ 0.5
Satisfy the relationship
The cleaning blade according to any one of claims 1 to 4, wherein the cleaning blade is provided. The Young's modulus of the surface of the first high Young's modulus part is Y ₀ , the Young's modulus at a position inside 20 μm from the first high Young's modulus part is Y ₂₀ , and the position inside 50 μm from the first high Young's modulus part. Young's modulus of the in case of a Y _50,
{(Y ₂₀ -Y ₅₀ ) / Y ₀ } / (50-20) ≦ {(Y ₀ -Y ₂₀ ) / Y ₀ } / (20-0)
Satisfy the relationship
The cleaning blade according to any one of claims 1 to 5, wherein Including the edge portion, facing the surface of the cleaning object, and having a facing surface continuous to the end surface;
The opposing surface has a second high Young's modulus portion having a surface Young's modulus higher than that in the depth direction in at least a part of the region including the region on the edge portion side.
The cleaning blade according to any one of claims 1 to 6, wherein The second high Young's modulus part includes the edge part,
The cleaning blade according to claim 7. The second high Young's modulus part has a gradient of Young's modulus that continuously increases from the inside toward the surface.
The cleaning blade according to claim 7 or 8, wherein The Young's modulus of the second high Young's modulus unit when the Y _0,
100 MPa ≦ Y ₀ ≦ 4000 MPa
Satisfy the relationship
The cleaning blade according to any one of claims 7 to 9, wherein When the Young's modulus of the surface of the second high Young's modulus part is Y ₀ , and the Young's modulus at a position inside 50 μm from the second high Young's modulus part is Y ₅₀ ,
Y ₅₀ / Y ₀ ≦ 0.5
Satisfy the relationship
The cleaning blade according to any one of claims 7 to 10, wherein The Young's modulus of the surface of the second high Young's modulus part is Y ₀ , the Young's modulus at a position inside 20 μm from the second high Young's modulus part is Y ₂₀ , and the position inside 50 μm from the second high Young's modulus part. Young's modulus of the in case of a Y _50,
{(Y ₂₀ -Y ₅₀ ) / Y ₀ } / (50-20) ≦ {(Y ₀ -Y ₂₀ ) / Y ₀ } / (20-0)
Satisfy the relationship
The cleaning blade according to any one of claims 7 to 11, wherein Made of urethane rubber containing isocyanurate groups,
The cleaning blade according to any one of claims 1 to 12, wherein The edge portion is in contact with the cleaning object so as to be in a counter direction with respect to the moving direction of the cleaning object;
The cleaning blade according to any one of claims 1 to 13, wherein the cleaning blade is provided. An image carrier that carries and moves a toner image;
Transfer means for transferring the toner image of the image carrier to another image carrier;
A cleaning blade according to any one of claims 1 to 14, and
The object to be cleaned is the image carrier, and the direction along the edge portion is a direction intersecting the moving direction of the image carrier.
An image forming apparatus.

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