Image forming device

Abstract

To suppress blade turn-up in an image forming apparatus having cleaning means for recovering toner by abutting on an image carrier.SOLUTION: An image forming apparatus 100 includes a sheet member 45 provided on the end side of a cleaning blade 31 with respect to a longitudinal direction of the cleaning blade 31 orthogonal to a belt conveyance direction. With respect to the longitudinal direction, a maximum area in which an image can be formed on a transfer material P having a maximum size usable in the image forming apparatus 100 is defined as an image forming area. In this case, at least a part of the sheet member 45 is provided in an area outside the image forming area, and on one end side of the cleaning blade 31, the sheet member 45 is provided inside the end of the cleaning blade 31.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copying machine or a printer, that utilizes an electrophotographic system. [Background technology]

[0002] In an image forming apparatus using an electrophotographic method, a transfer voltage is applied to a transfer member disposed opposite an image carrier such as a drum-shaped photoreceptor or intermediate transfer member, and a toner image carried by the image carrier is electrostatically transferred to a transfer material such as paper or an OHP sheet. In such an image forming apparatus, after the transfer is completed, toner (transfer residual toner) remains on the image carrier. Therefore, it is necessary to remove the transfer residual toner remaining on the image carrier before forming an image corresponding to the next image.

[0003] A blade cleaning method is widely used as a cleaning method for removing the residual toner after transfer. In the blade cleaning method, the residual toner after transfer is scraped off by a cleaning blade as a contact member that contacts the image carrier and collected in a cleaning container. An elastic body such as urethane rubber is generally used as the cleaning blade. This cleaning blade is often arranged in a state where the edge of the cleaning blade is pressed against the image carrier from a direction (counter direction) opposite to the rotation direction (movement direction) of the image carrier.

[0004] In addition, in a configuration in which the transfer residual toner is collected by a cleaning blade, a configuration is widely known in which a cleaning blade that is longer in the axial direction of the image carrier than the width of the opening of the developer container in which the toner is stored is used in order to sufficiently collect the transfer residual toner. In such a configuration, since there is almost no toner in the area of ​​the image carrier corresponding to the outside of the opening in the longitudinal direction, the frictional force between the image carrier and the cleaning blade is likely to be large in that area. If the frictional force acting on the edge of the cleaning blade becomes large, a phenomenon called blade curling may occur in which the edge of the cleaning blade arranged opposite the image carrier comes into contact with the image carrier in the forward direction relative to the rotation direction of the image carrier.

[0005] Patent Document 1 discloses a configuration in which a cleaning blade having high hardness only at both side ends in the longitudinal direction is used to prevent the occurrence of blade curling. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2009-63993 A Summary of the Invention [Problem to be solved by the invention]

[0007] According to the configuration of Patent Document 1, it is possible to prevent the cleaning blade from curling up by performing a hardening process on the cleaning blade, but there is a risk that continued contact of the hardened cleaning blade will promote wear on the image carrier.

[0008] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS The present invention has an object to provide an embodiment capable of suppressing blade curling in an image forming apparatus having a cleaning unit that contacts an image carrier to collect toner. [Means for solving the problem]

[0009] The present invention provides a toner image forming apparatus comprising: an image carrier that carries a toner image; an endless intermediate transfer body that is movable and in contact with the image carrier; and a recovery unit for recovering toner remaining on the intermediate transfer body, the recovery unit having a contact member that contacts the intermediate transfer body to recover the toner remaining on the intermediate transfer body, and a support member that supports the contact member. The contact member moves perpendicularly to the moving direction of the intermediate transfer body. The direction of the contact member The longitudinal direction is extended. ,before Perpendicular to the longitudinal direction The direction of the contact member One end side in the short direction is fixed to the support member. R, The other end Contact with the intermediate transfer body Free end And the abutting member is , the abutment member with respect to the longitudinal direction On the other hand Sheet-shaped Reinforcement a member having a length in the longitudinal direction , painting When the maximum area in which an image can be formed on a transfer material of the maximum size that can be used in an image forming apparatus is defined as the image forming area, Reinforcement Department The material is Area outside the image forming area a region corresponding to a region of the intermediate transfer body having a higher coefficient of friction than the image forming region, To only Established R, and, The reinforcing member is At one end side of the abutting member, With respect to the longitudinal direction , the abutment member Edge Inside and the contact member is provided between a first position and a second position, the first position being closer to the end of the contact member than a boundary between the image forming area and the non-image forming area in the longitudinal direction, and the second position being a position provided on an opposite side to a center of the contact member with respect to the first position in the longitudinal direction, and being disposed between the first position and the end of the contact member. It is characterized by: Effect of the Invention

[0010] According to the present invention, it is possible to provide an embodiment capable of suppressing blade curling in an image forming apparatus having a cleaning unit that contacts an image carrier to collect toner. [Brief description of the drawings]

[0011] [Figure 1] Schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. [Diagram 2] Schematic cross-sectional view of an intermediate transfer belt according to a first embodiment of the present invention. [Diagram 3]FIG. 1 is a schematic cross-sectional view illustrating a configuration of a belt cleaning unit in a first embodiment. [Figure 4] FIG. 1 is a schematic perspective view illustrating a configuration of a cleaning blade in a first embodiment. [Diagram 5] FIG. 1 is a schematic diagram illustrating a sealing member provided at an end of a cleaning blade in Example 1. [Figure 6] FIG. 1 is a schematic cross-sectional view illustrating a configuration of a sheet member according to a first embodiment. [Figure 7] FIG. 1 is a schematic diagram illustrating a configuration for suppressing wear at an end portion of a cleaning blade in a longitudinal direction in the first embodiment; [Figure 8] FIG. 1 is a schematic diagram illustrating a state in which wear occurs at the end of a cleaning blade in a comparative example; [Figure 9] FIG. 1 is a schematic diagram illustrating the arrangement of sheet members in the first embodiment; [Figure 10] FIG. 1 is a schematic diagram illustrating another embodiment of Example 1. [Figure 11] Schematic diagram illustrating the width relationship of each member in the longitudinal direction [Figure 12] Schematic diagrams illustrating the arrangement of sheet members in Modifications 1 to 8. [Figure 13] FIG. 13 is a schematic diagram illustrating another configuration of the arrangement position of the sheet member in the first modified example. [Figure 14] FIG. 23 is a schematic diagram illustrating another configuration of the arrangement position of the sheet member in the seventh modification example. [Figure 15] FIG. 11 is a schematic cross-sectional view illustrating the configuration of a sheet member according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Example 1 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions. Therefore, unless otherwise specified, the scope of the present invention is not intended to be limited.

[0013] <Image forming device overview> FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus 100 of this embodiment. The image forming apparatus 100 of this embodiment is a so-called tandem type image forming apparatus having a plurality of image forming units. The first image forming unit Sa forms an image using toner of each color, yellow (Y), the second image forming unit Sb forms an image using toner of each color, magenta (M), the third image forming unit Sc forms an image using toner of each color, cyan (C), and the fourth image forming unit Sd forms an image using toner of each color, black (Bk). These four image forming units are arranged in a line at regular intervals, and the configuration of each image forming unit has many parts that are substantially the same except for the color of the toner that is contained therein. Therefore, the image forming apparatus 100 of this embodiment will be described below using the first image forming unit Sa.

[0014] The photosensitive drum 1a is a metal cylinder having multiple layers of functional organic materials laminated thereon, including a carrier generation layer that generates charges upon exposure to light and a charge transport layer that transports the generated charges, and the outermost layer has low electrical conductivity and is almost insulating. The photosensitive drum 1a receives a driving force from a driving source (not shown) and rotates at a predetermined peripheral speed in the direction of the arrow R1 in the figure.

[0015] The charging roller 2a as a charging member contacts the photosensitive drum 1a and uniformly charges the surface of the photosensitive drum 1a while rotating in accordance with the rotation of the photosensitive drum 1a indicated by the arrow R1 in the figure. When a DC voltage is applied from a charging power source 20a, the charging roller 2a charges the photosensitive drum 1a by discharge generated in a minute air gap upstream and downstream of a charging portion where the charging roller 2a and the photosensitive drum 1a contact each other.

[0016] The developing means 8a has a developing roller 4a as a developing member and a developer coating blade 7a, and contains yellow toner. The developing roller 4a is connected to a developing power source 21a. The cleaning means 3a has a cleaning blade that contacts the photosensitive drum 1a and a waste toner box that contains toner and the like removed from the photosensitive drum 1a by the cleaning blade, and collects the toner remaining on the photosensitive drum 1a. The exposure means 11a is composed of a scanner unit that scans laser light using a polygon mirror, and irradiates the photosensitive drum 1a with a scanning beam 12a modulated based on an image signal. The photosensitive drum 1a, the charging roller 2a, the cleaning means 3a, and the developing means 8a are configured as an integrated process cartridge 9a that is detachable from the image forming apparatus 100.

[0017] The intermediate transfer belt 13 is tensioned by three rollers, namely, a secondary transfer opposing roller 15 (hereinafter referred to as the opposing roller 15) as a tensioning member, a tension roller 14, and an auxiliary roller 19. The tension roller 14 is biased by a spring (not shown) so that an appropriate tension is maintained on the intermediate transfer belt 13. The opposing roller 15 receives a driving force from a driving source (not shown) and rotates in the direction of the arrow R2 shown in the figure, and the intermediate transfer belt 13 moves in the direction of the arrow AA shown in the figure with the rotation of the opposing roller 15. The intermediate transfer belt 13 can move in the forward direction relative to the photosensitive drums 1a to 1d at approximately the same speed.

[0018] The auxiliary roller 19, the tension roller 14, and the counter roller 15 are electrically grounded. The counter roller 15 is a roller having an outer diameter of 24.0 mm and formed by covering an aluminum core with an elastic layer (EPDM rubber) having a thickness of 0.5 mm, and has an electrical resistance of about 1×10 5 To make the resistance Ω, carbon is dispersed in the EPDM rubber as a conductive agent.

[0019] The primary transfer roller 10a is disposed at a position facing the photosensitive drum 1a via the intermediate transfer belt 13, contacts the inner peripheral surface of the intermediate transfer belt 13, and is rotated in accordance with the movement of the intermediate transfer belt 13. The secondary transfer roller 25 is disposed at a position facing the counter roller 15 via the intermediate transfer belt 13, and contacts the outer peripheral surface of the intermediate transfer belt 13. The secondary transfer roller 25 is also connected to a secondary transfer power source 26.

[0020] Next, an image forming operation of the image forming apparatus 100 of the present invention will be described. When a control means (not shown) such as a controller receives an image signal, the image forming operation is started, and the photosensitive drums 1a to 1d, the opposing roller 15, etc. start to rotate at a predetermined peripheral speed (process speed) by a driving force from a driving source (not shown). In this embodiment, the process speed is 200 mm / s.

[0021] The photosensitive drum 1a is uniformly charged by the charging roller 2a to which a voltage of the same polarity as the normal charging polarity of the toner (negative polarity in this embodiment) is applied from the charging power source 20a. Then, an electrostatic latent image according to the image information is formed by irradiating the photosensitive drum 1a with a scanning beam 12a from the exposure means 11a. The toner contained in the developing means 8a is negatively charged by the developer application blade 7a and applied to the developing roller 4a. Then, by applying a predetermined voltage from the development power source 21a to the developing roller 4a, the electrostatic latent image is developed with toner at a developing section where the developing roller 4a and the photosensitive drum 1a come into contact with each other, and a toner image corresponding to the yellow image component is formed on the photosensitive drum 1a.

[0022] Thereafter, as the photosensitive drum 1a rotates, the yellow toner image carried on the photosensitive drum 1a reaches a primary transfer portion N1a where the photosensitive drum 1a contacts the intermediate transfer belt 13. Then, a positive voltage is applied from the primary transfer power source 22a to the primary transfer roller 10a, whereby the yellow toner image is primarily transferred from the photosensitive drum 1a to the intermediate transfer belt 13 at the primary transfer portion N1a.

[0023] Similarly, a magenta toner image of the second color, a cyan toner image of the third color, and a black toner image of the fourth color are formed by the second, third, and fourth image forming units Sb, Sc, and Sd, and are primarily transferred onto the intermediate transfer belt 13 in a superimposed manner. As a result, four-color toner images corresponding to the target color image are formed on the intermediate transfer belt 13. Thereafter, the four-color toner images carried on the intermediate transfer belt 13 are secondarily transferred collectively onto the surface of the transfer material P, such as paper or an OHP sheet, in the process of passing through the secondary transfer portion N2 formed by the contact between the secondary transfer roller 25 and the intermediate transfer belt 13. At this time, a positive voltage is applied from the secondary transfer power source 26 to the secondary transfer roller 25, so that the toner image is secondarily transferred from the intermediate transfer belt 13 to the transfer material P at the secondary transfer portion N2.

[0024] The transfer material P is stored in a paper feed cassette 16, and is fed from the paper feed cassette 16 by a paper feed roller 17 toward a transport roller 18, and then transported by the transport roller 18 toward a secondary transfer portion N2. The transfer material P onto which the four-color toner image has been transferred in the secondary transfer portion N2 is then heated and pressurized in a fixing means 50, whereby the four-color toner is melted, mixed, and fixed onto the transfer material P. The transfer material P is then discharged from the image forming apparatus 100, and is stacked on a paper output tray 52 serving as a stacking portion.

[0025] Residual toner remaining on the intermediate transfer belt 13 after the secondary transfer is removed from the surface of the intermediate transfer belt 13 by a belt cleaning means 30 (recovery means) provided opposite the opposing roller 15 across the intermediate transfer belt 13. As will be described in detail later, the belt cleaning means 30 has a cleaning blade 31 (contact member) that contacts the outer circumferential surface of the intermediate transfer belt 13 at a position opposite the opposing roller 15.

[0026] In the image forming apparatus 100 of this embodiment, a full-color print image is formed by the above operations.

[0027] The image forming apparatus 100 of this embodiment is provided with a control board (not shown) on which electric circuits for controlling the operation of each part of the image forming apparatus are mounted. The control board is equipped with a CPU (not shown) as a control means, and a memory (not shown) as a storage means in which various control information is stored. The CPU executes control related to the transport of the transfer material P, control related to the driving of the intermediate transfer belt 13 and the process cartridge 9, control related to image formation, and further control related to failure detection.

[0028] <Intermediate transfer belt> Next, the configuration of the intermediate transfer belt 13 as an image carrier in this embodiment will be described with reference to FIG. 2. FIG. 2 is a schematic enlarged cross-sectional view of the intermediate transfer belt 13 cut in a direction substantially perpendicular to the belt conveying direction of the intermediate transfer belt 13 (seen along the belt conveying direction). As shown in FIG. 2, the intermediate transfer belt 13 is an endless belt member (or a film-like member) consisting of two layers, a base layer 41 and a surface layer 40, and the peripheral length of the intermediate transfer belt 13 is 700 mm. Here, the base layer is defined as the thickest layer among the layers constituting the intermediate transfer belt 13 in the thickness direction of the intermediate transfer belt 13. In this embodiment, the base layer 41 is a layer having a thickness of 70 μm, in which a quaternary ammonium salt, which is an ion conductive agent, is dispersed as an adjuster of electrical resistance in a polyethylene naphthalate resin. The surface layer 40 is formed on the outer peripheral surface side of the intermediate transfer belt 13, and is a layer in which antimony-doped zinc oxide is dispersed as an adjuster of electrical resistance in an acrylic resin as a base material. In this embodiment, the thickness of the surface layer 40 is set to 3 μm. In addition, in order to improve the friction coefficient μ of the surface, it is also possible to add polytetrafluoroethylene (PTFE) particles or the like as a solid lubricant to the surface layer 40.

[0029] <Cleaning Method> Next, the configuration of the belt cleaning means 30 will be described. Fig. 3(a) is a schematic virtual cross-sectional view illustrating the attachment position of the cleaning blade 31 when the cleaning blade 31 described below is not elastically deformed. Fig. 3(b) is a schematic cross-sectional view illustrating the configuration of the belt cleaning means 30 in a state where it is attached to the image forming apparatus 1. Fig. 4 is a schematic perspective view illustrating the configuration of the cleaning blade 31.

[0030] The belt cleaning means 30 has a cleaning container 32 and a cleaning member 33 provided in the cleaning container 32. The cleaning container 32 is configured as a part of a frame of an intermediate transfer unit (not shown) having the intermediate transfer belt 13 and the like. The cleaning member 33 has a cleaning blade 31 as a contact member that contacts the intermediate transfer belt 13, and a support member 34 that supports the cleaning blade 31. The cleaning blade 31 is an elastic blade made of urethane rubber (polyurethane), which is an elastic material, and is supported in a state where it is adhered to the support member 34, which is formed of sheet metal made of plated steel.

[0031] As shown in Figs. 3(a)-(b) and 4, the cleaning blade 31 is a plate-like member that is long in the width direction (longitudinal direction of the cleaning blade 31) of the intermediate transfer belt 13 that is perpendicular to the moving direction of the intermediate transfer belt 13 (hereinafter referred to as the belt conveying direction). Hereinafter, the definitions of the longitudinal direction, the transverse direction, and the thickness direction are used as shown in Fig. 4 to explain the directions of the cleaning blade 31. Hereinafter, the longitudinal direction is a direction parallel to the width direction of the intermediate transfer belt 13. The transverse direction is a direction perpendicular to the longitudinal direction, and is a direction from the fixed end side (one end side) of the cleaning blade 31 to the free end side (the other end side) when viewed from the rotation axis direction of the opposing roller 15. The thickness direction is the thickness direction of the cleaning blade 31, and is a direction that intersects (is perpendicular to) the longitudinal direction and the transverse direction.

[0032] As shown in FIG. 3(a), the cleaning blade 31 has a fixed end 31a fixed to a support member 34, a free end 31c provided on the opposite side of the fixed end 31 in the short direction, an end face 31b on the free end side, a first face 31e, and a second face 31f. Here, the first face is a face extending in the longitudinal direction of the cleaning blade 31 and facing the outer peripheral surface of the intermediate transfer belt 13. The second face is a face extending in the longitudinal direction of the cleaning blade 31 and provided on the opposite side of the first face in the thickness direction. In addition, the cleaning blade 31 has an end face 31d at the end of the free end, which is a face perpendicular to the first face 31e and the second face 31f and extends in the longitudinal direction.

[0033] 3(b), the cleaning blade 31 is disposed such that an end portion (free end 31c) on the free end side that is not fixed to the support member 34 contacts the intermediate transfer belt 13 in a lateral direction perpendicular to the longitudinal direction of the cleaning blade 31. The cleaning blade 31 is fixed in a state in which a part of the second surface 31f is adhered to the support member 34. The length of the cleaning blade 31 in the longitudinal direction is 240 mm, the thickness is 2 mm, and the hardness of the cleaning blade 31 is 77 degrees according to the JIS K 6253 standard.

[0034] The cleaning member 33 is configured to be swingable relative to the surface of the intermediate transfer belt 13. That is, the support member 34 is supported via a swing shaft 35 fixed to the cleaning container 32 so as to be swingable relative to the surface of the intermediate transfer belt 13. When the support member 34 is pressed by a pressure spring 36 as a biasing means provided in the cleaning container 32, the cleaning member 33 moves around the swing shaft 35, and the cleaning blade 31 is biased (pressed) against the intermediate transfer belt 13.

[0035] Opposing the cleaning blade 31, an opposing roller 15 is disposed on the inner peripheral side of the intermediate transfer belt 13. The cleaning blade 31 is in contact with the surface of the intermediate transfer belt 13 in a counter direction to the belt transport direction at a position opposing the opposing roller 15. That is, the cleaning blade 31 is in contact with the surface of the intermediate transfer belt 13 such that an end face 31b on the free end side in the short side direction faces the upstream side in the belt transport direction.

[0036] 3(b), a blade nip portion 37 is formed between the cleaning blade 31 and the intermediate transfer belt 13. When the blade nip portion 37 is formed, the free end 31c of the cleaning blade 31 comes into strong contact with the intermediate transfer belt 13, scrapes off the residual toner from the surface of the moving intermediate transfer belt 13, and collects it in the cleaning container 32.

[0037] In this embodiment, the attachment position of the cleaning blade 31 is set as follows. As shown in FIG. 3(a), the set angle θ is 22°, the penetration amount δ is 1.3 mm, and the contact pressure is 0.6 N / cm. Here, the set angle θ is the angle between the tangent of the opposing roller 15 at the intersection of the intermediate transfer belt 13 and the cleaning blade 31 (more specifically, the end surface on the free end side) and the cleaning blade 31 (more specifically, one surface substantially perpendicular to the thickness direction). The penetration amount δ is the length in the thickness direction where the cleaning blade 31 overlaps with the opposing roller 15. The contact pressure is defined as the pressing force (linear pressure in the longitudinal direction) from the cleaning blade 31 at the blade nip portion 37, and is measured using a film-type pressure measuring system (product name: PINCH, manufactured by Nitta Corporation).

[0038] In addition, urethane rubber and synthetic resin generally have a large frictional resistance due to sliding, and initial curling of the cleaning blade 31 tends to occur, with the direction of the cleaning blade 31 becoming aligned with the rotation direction of the intermediate transfer belt 13. Therefore, an initial lubricant such as graphite fluoride can be applied in advance to the free end 31c where the cleaning blade 31 comes into contact with the intermediate transfer belt 13. In order to prevent curling of the cleaning blade 31, it is preferable to also apply an initial lubricant to the end face 31b on the free end side and to an area of ​​500 μm or more near the free end 31c of the first surface 31e.

[0039] The rubber hardness and contact pressure of the cleaning blade 31 are appropriately selected to ensure cleaning performance. If the contact pressure is too weak, the toner cannot be scraped off and slips through, causing poor cleaning, while if the contact pressure is too strong, the cleaning blade 31 wears out, causing poor cleaning due to the toner slipping through. Similarly, if the rubber hardness of the cleaning blade 31 is too hard, the toner cannot be scraped off and slips through, causing poor cleaning. Also, if the rubber hardness is too soft, the cleaning blade 31 wears out, causing poor cleaning due to the toner slipping through. Therefore, the rubber hardness and contact pressure of the cleaning blade 31 are appropriately selected to ensure cleaning performance. The rubber hardness of the cleaning blade 31 is appropriately selected depending on the material of the intermediate transfer belt 13, but is preferably in the range of 70 degrees or more and 80 degrees or less according to the JIS K 6253 standard. Also, the contact pressure of the cleaning blade 31 is preferably in the range of 0.4 N / cm or more and 0.8 N / cm or less.

[0040] Next, the length of the cleaning blade 31 in the longitudinal direction will be described, including its relationship with other members.

[0041] In this embodiment, the width of the cleaning blade 31 in the longitudinal direction is 240 mm. The width of the cleaning blade 31 is set to be equal to or greater than the width of the area on the intermediate transfer belt 13 to which toner may be supplied. In the configuration of this embodiment, the width of the charging roller 2 (the width of the area where the surface of the photosensitive drum 1 can be charged) is 230 mm, and the width that can be exposed by the operation beam 12 of the exposure means 11 of the scanner unit is 226 mm. Therefore, by setting the width of the cleaning blade 31 to 230 mm or more, the entire area to which toner may be supplied can be covered by the cleaning blade 31, and all the toner on the intermediate transfer belt 13 can be collected by the cleaning blade 31.

[0042] Here, it is also important that the toner collected by the cleaning blade 31 does not leak from the cleaning container 32 onto the intermediate transfer belt 13. If the toner leaks out, it may cause toner stains on other parts, resulting in poor images. For this reason, generally, sealing members are provided at the longitudinal end portions of the cleaning blade 31 to prevent the formation of paths through which the toner can leak.

[0043] 5 is a schematic diagram illustrating an end seal 46 as a sealing member provided at the end of the cleaning blade 31 in this embodiment. As shown in FIG. 5, in the configuration of this embodiment, an end seal 46 is provided at each of both ends in the longitudinal direction of the cleaning blade 31. The end seal 46 is provided in contact with the end of the cleaning blade 31. In this manner, by arranging each member so as not to create a gap between the cleaning blade 31 and the end seal 46, the toner collected by the cleaning blade 31 is prevented from leaking from the cleaning container 32 onto the intermediate transfer belt 13.

[0044] The toner collected by the cleaning blade 31 is transported to the waste toner storage unit as waste toner. In this embodiment, the toner collected by the cleaning blade 31 is transported to the waste toner storage unit outside the cleaning container 32 by a transport mechanism having a screw 47 shown in Fig. 3. This allows waste toner to be collected until the waste toner storage unit is filled to capacity, and a sufficient amount of waste toner can be collected even during a long lifespan.

[0045] [Strengthened cleaning blade configuration] In a configuration in which the width of the cleaning blade 31 in the longitudinal direction is longer than the area to which toner is supplied, there are areas on both sides of the cleaning blade 31 where toner is not supplied or the amount of toner supplied is small. In areas where toner supply is small, the decrease in the friction coefficient μ due to toner supply is small, and therefore the friction force μN acting between the intermediate transfer belt 13 and the cleaning blade 31 becomes large. When the friction force μN becomes large, the force with which the cleaning blade 31 is wrapped by the intermediate transfer belt 13 increases, so that the cleaning blade 31 is likely to turn forward relative to the belt conveyance direction, i.e., the so-called blade curl. If such blade curl occurs, the cleaning performance decreases, which may cause image defects due to poor cleaning.

[0046] In particular, when a pattern with a low printing rate (low printing pattern) continues during image formation, the amount of toner supplied to the opposing side of the cleaning blade 31 tends to decrease. Also, when the image formation conditions include forming an image concentrated in the center of the transfer material, or continuously using small-sized transfer materials, the toner supply to the end portions in the longitudinal direction of the cleaning blade 31 tends to decrease. Thus, under image formation conditions that result in a small amount of toner supply, the friction force μN becomes even larger, making blade curling more likely to occur.

[0047] From the above, it is preferable to adopt a configuration in which the cleaning blade 31 is reinforced and the cleaning blade 31 is less likely to deform so as not to cause blade curling in areas where toner is supplied in small amounts. In addition, when the friction coefficient μ of the surface of the intermediate transfer belt 13, which is the opposing member of the cleaning blade 31, is high, for example, when a material having high tackiness with the cleaning blade 31 is used as the surface layer 40, the blade curling is more likely to occur. Therefore, in a configuration in which the friction coefficient μ of the surface of the intermediate transfer belt 13 is high, the reinforcement of the cleaning blade 31 is more effective. Here, for example, the acrylic resin described in this embodiment as the material of the surface layer 40 has high tackiness with the urethane rubber of the cleaning blade 31 and corresponds to a configuration in which the friction coefficient μ of the intermediate transfer belt 13 is high.

[0048] A specific configuration for suppressing blade curling in this embodiment will be described below. FIG. 6 is a schematic cross-sectional view for explaining the configuration of the sheet member 45 as a reinforcing member provided on the cleaning blade 31 of this embodiment. As described above, in the configuration of this embodiment, there is a region in which the frictional force between the intermediate transfer belt 13 and the cleaning blade 31 changes between the inside and outside of the image forming region in the longitudinal direction of the cleaning blade 31. Here, the image forming region is defined as the maximum region in which an image can be formed on a transfer material P that has the maximum width in the width direction (longitudinal direction) perpendicular to the conveying direction of the transfer material P among the transfer materials P that can be used in the image forming apparatus 100. That is, for example, when the transfer material P of the maximum size that can be used in the image forming apparatus 100 is letter size, the maximum width in the longitudinal direction in which an image can be formed on the transfer material P of letter size is the image forming region defined in this embodiment.

[0049] The remaining transferred toner may be supplied to the area inside the image forming area in the longitudinal direction, but no toner is supplied outside the image forming area, and the friction coefficient μ of the intermediate transfer belt 13 may differ between the inside and outside of the image forming area. In other words, the μ of the intermediate transfer belt 13 becomes higher outside the image forming area, and there is a possibility that the blade may turn over. In this embodiment, the cleaning blade 31 is reinforced outside the image forming area to suppress the occurrence of turning over at the longitudinal end of the cleaning blade 31.

[0050] As a reinforcing method in this embodiment, as shown in FIG. 6, a sheet member 45 is attached to the cleaning blade 31. The sheet member 45 is attached to a second surface 31f of the cleaning blade 31 opposite to a first surface 31e facing the intermediate transfer belt 13. More specifically, the sheet member 45 is provided between the end seal 46 and the second surface 31f in the thickness direction. In this configuration, the sheet member 45 is provided at a position that does not face the toner carried on the intermediate transfer belt 13, in other words, at a position that faces the internal region of the cleaning container 32. The reinforcing configuration of the cleaning blade 31 will be described in detail later.

[0051] Here, the area where the sheet member 45 is attached in the longitudinal direction of the cleaning blade 31 that is reinforced as shown in Fig. 6 will be described. It is effective to reinforce the cleaning blade 31 in the area outside the image forming area where the friction coefficient μ is high, as described above, but at the same time, in order to ensure cleaning performance, it is necessary to ensure the toner sealing performance between the end seal 46. In order to ensure the toner sealing performance, it is effective to prevent wear at the cleaning blade end.

[0052] Fig. 7 is a schematic diagram illustrating a configuration for suppressing wear at the end portion in the longitudinal direction of the cleaning blade 31. Fig. 8 is a schematic diagram illustrating a state in which wear occurs at the end portion of the cleaning blade in the configuration of a comparative example (Comparative Example 2 described later). Below, a configuration for preventing wear at the end portion of the cleaning blade 31 will be described with reference to Figs. 7 and 8. In this embodiment, as shown in Fig. 7, an end region 38 to which no sheet member 45 is attached is provided in the longitudinal direction of the cleaning blade 31.

[0053] As shown in the comparative configuration of Fig. 8, according to the study by the present inventors, it was found that in a configuration in which a sheet member is provided over the entire end of the cleaning blade 31, wear is accelerated at the end of the cleaning blade 31. When wear of the cleaning blade is accelerated on the end side in this way, it becomes impossible to seal the toner between the end seal 46 and the cleaning blade 31, and the toner leaks out to the end side as shown in Fig. 8. When this leakage occurs, the toner may unexpectedly adhere to other members and cause stains, which may lead to image defects and performance degradation.

[0054] In consideration of the above, in the configuration of this embodiment, in order to maintain toner sealing, an end region 38 (open region) that is not reinforced by the sheet member 45 in the longitudinal direction of the cleaning blade 31 is provided as shown in Fig. 7. In this embodiment, the length (width) in the longitudinal direction of the end region 38 is set to 500 µm. Here, in order to seal in the toner, it is preferable to set the width in the longitudinal direction of the end region 38 to 250 µm or more.

[0055] Fig. 9 is a schematic diagram for explaining the arrangement of the sheet member 45 in the configuration of this embodiment. As shown in Fig. 9, in the longitudinal direction of the cleaning blade 31, the sheet member 45 is provided in an area outside the image forming area (including the boundary of the image forming area) and excluding the end area 38. A specific description will be given of the reinforcing configuration of the sheet member 45 attached to the above-mentioned area of ​​the cleaning blade 31.

[0056] In the configuration of this embodiment, the elastic modulus of the entire cleaning member 33, which is a combination of the sheet member 45, the support member 34, and the cleaning blade 31, is improved, thereby suppressing the deformation of the cleaning blade 31 and suppressing the occurrence of blade curling. Specifically, the sheet member 45 is attached to the second surface 31f of the cleaning blade 31 to reinforce the cleaning blade 31, and the elastic modulus of the cleaning member 33 is improved in the portion in the longitudinal direction where the sheet member 45 is attached. More specifically, a lumirror sheet having a thickness of 100 μm is attached as the sheet member 45 to the cleaning blade 31 with double-sided tape. The attachment area is as shown in FIG. 9. In addition, as the area where the sheet member 45 is attached in the lateral direction, it is more preferable to attach the sheet member 45 to the entire lateral side of the cleaning blade 31, from the viewpoint of increasing the overall elastic modulus of the cleaning member 33 by the sheet member 45.

[0057] In the above embodiment, the sheet member 45 is a lumirror sheet having a thickness of 100 μm, which is attached to the cleaning blade 31 with double-sided tape. However, the present invention is not limited to this configuration, and it is sufficient that the elastic modulus of the entire cleaning member 33 can be improved by attaching the sheet member 45 to the cleaning blade 31. For example, the thickness of the sheet member 45 may be 200 μm instead of 100 μm. In this case, since the thickness of the sheet member 45 increases, it is possible to improve the elastic modulus of the entire cleaning member 33 without attaching it to the entire short-side direction. Therefore, as shown in FIG. 10, the sheet member 45 may be provided by leaving an area of ​​about 1 mm on the free end side, instead of providing the sheet member 45 over the entire short-side direction. The material of the sheet member 45 is not limited to the lumirror sheet. If the hardness of the sheet member 45 is higher than that of the cleaning blade 31, the elastic modulus of the portion of the cleaning member 33 to which the sheet member 45 is attached in the long-side direction can be improved by attaching the sheet member 45. For example, a metal foil composite film is also a preferable configuration because of its hardness.

[0058] In addition, when another preferable configuration is required, the appropriateness can be judged from the elastic modulus of the entire cleaning member 33. The elastic modulus of the entire cleaning member 33 will be described. The force and deformation amount of the cleaning blade 31 of the cleaning member 33 will be considered. In the configuration of this embodiment, the fixed end side of the cleaning blade 31 is fixed to the support member 34, and the tip portion (free end side) of the cleaning blade 31 receives a force generated between the intermediate transfer belt 13. From this, the force and deformation amount of the cleaning blade 31 can be considered as the distortion of a cantilever beam that receives a force at the tip portion of the free end side with one fixed end. Then, using the frictional force F received by the cleaning blade 31, the deformation amount Δ of the cleaning blade 31, the blade elastic modulus E, the free length L, and the second moment of area I, the deformation amount Δ of the cleaning blade 31 can be expressed by the following formula 1.

[0059]

number

[0060] The area second moment I is due to the cross-sectional shape of the deformation point of the cleaning blade 31, and if there is no deformation in the longitudinal direction, there is no difference in the longitudinal direction. That is, referring to formula 1, when the frictional force F is large and the other parameters are the same, the deformation amount Δ of the cleaning blade 31 increases by the amount of the increase in the frictional force F, and as a result, the risk of curling increases. Therefore, in this embodiment, the blade elasticity modulus E is increased by providing the sheet member 45. For example, if the combined elasticity modulus of the cleaning blade 31 and the sheet member 45 is increased by 1.5 times by the attached sheet member 45, the deformation amount of the cleaning blade 31 in the reinforced portion can be made the same as that of the other portions up to a frictional force F of 1.5 times.

[0061] Next, a method for measuring the relative elastic modulus due to reinforcement will be described. From the above formula 1, it can be seen that when the same force is applied to an area of ​​the same width with the same free length, the deformation amount Δ and the elastic modulus E are inversely proportional. Therefore, a string was tied to the tip of the cleaning blade 31 so that a force is applied to the tip of the cleaning blade 31 in contact with the intermediate transfer belt 13, and a weight was tied to the string, and the elastic modulus E of the cleaning member 33 was evaluated based on the deformation amount Δ when the same force was applied. In this embodiment, the end side of the cleaning member 33 in the longitudinal direction is reinforced by the sheet member 45 so that the attached portion of the sheet member 45 has a modulus of elasticity E twice that of the central portion in the longitudinal direction of the cleaning blade 31.

[0062] <Effects> The results of comparing this embodiment with Comparative Example 1 will be described. Comparative Example 1 has a configuration in which the sheet member 45 is not attached to the cleaning blade. Evaluation was performed using the measurement of the deformation amount Δ described above for Comparative Example 1 and this embodiment. In detail, the cleaning blade 31 is pulled so that a force of 100 gf is applied to the tip portion, and the deformation amount Δ of the cleaning blade 31 at that time is compared. As a result, as shown in Table 1 below, the deformation amount Δ of Comparative Example 1 is about twice that of Example 1. As described above, compared to the configuration of Comparative Example 1, the configuration of this embodiment in which the sheet member 45 is attached has a smaller deformation amount Δ of the cleaning blade 31, that is, the cleaning blade 31 is less likely to deform. In the configuration of this embodiment, the elastic modulus of the cleaning member 33 is improved by the sheet member 45, which makes it possible to suppress the occurrence of blade curling of the cleaning blade 31.

[0063] [Table 1]

[0064] Next, as Comparative Example 2, a configuration in which a sheet member is attached to the entire end area outside the image forming area in the longitudinal direction of the cleaning blade is used, and the influence at that time is described. When a sheet member is attached to the entire end area in the longitudinal direction, as previously described with reference to FIG. 8, wear at the end of the cleaning blade progresses, and there is a risk of a path being created for toner leakage. Below, a wear evaluation performed for this Example and Comparative Example 2 and the results thereof are described. Specifically, the wear state at the end of the cleaning blade after image formation on 3,000 sheets of transfer material was observed, and wear evaluation was performed from the amount of wear at the end.

[0065] The amount of wear was measured by releasing the contact state of the cleaning blade 31 with the intermediate transfer belt 13 and observing the end surface 31b of the cleaning blade 31 on the free end side near the free end 31c in contact with the intermediate transfer belt 13 with a microscope. The microscope used for the measurement was a confocal microscope (OPTELICS, manufactured by Lasertec Corporation). The observation area was 100 μm square, the measurement wavelength was 546 nm, and the scanning frequency in the perpendicular direction to the contact position of the cleaning blade 31 was 0.1 μm. To compare Comparative Example 2 with this embodiment, the maximum values ​​of wear in an area 500 μm wide from the end in the longitudinal direction were compared.

[0066] The results of the wear evaluation are shown in Table 2 below. As shown in Table 2, the amount of wear at the end was large in Comparative Example 2. On the other hand, although wear occurred on the end side of the cleaning blade 31 in this embodiment, it did not lead to toner leakage and the amount of wear was within an acceptable range. Thus, according to the study by the inventors, results were obtained in which the wear state of the end of the cleaning blade differed depending on whether or not the sheet member 45 was provided by providing the end region 38 (open region) that does not have the sheet member 45 in the longitudinal direction.

[0067] [Table 2]

[0068] (Modification) The configurations of various modified examples of the first embodiment will be described below. In the description of the first embodiment, a configuration in which the sheet member 45 is provided outside the image forming area in the longitudinal direction has been described. Below, a number of variations in the arrangement position of the sheet member 45 outside the image forming area in the longitudinal direction will be described using a number of modified examples. FIG. 11 is a schematic diagram for explaining the width of each member and each area in the longitudinal direction in this embodiment. Also, FIGS. 12(a) to (f) are schematic diagrams for explaining the configurations of modified examples 1 to 8, respectively.

[0069] First, the frictional force generated between the cleaning blade 31 and the intermediate transfer belt 13 in the regions corresponding to the respective widths shown in FIG. 11 will be described.

[0070] Within the image forming area, toner that has not been transferred to the transfer material P and remains on the intermediate transfer belt 13 reaches the opposing portion of the cleaning blade 31. On the other hand, outside the image forming area, there is no supply of such toner remaining after transfer, so the frictional force between the cleaning blade 31 and the intermediate transfer belt 13 tends to be higher than within the image forming area. Here, the definition of the image forming area is as explained above, but for example, the width of the image forming area based on letter size in the image forming apparatus 100 of this embodiment is 206 mm when the margin is set to within 5 mm.

[0071] Next, the paper passing area will be described. The paper passing area in this embodiment is an area in the longitudinal direction through which the transfer material P can pass, and its length corresponds to the width of the maximum size of the transfer material P that can be formed in the image forming apparatus 100. In the paper passing area, paper dust originating from the transfer material P may reach the opposing portion of the cleaning blade 31. Due to the supply of such paper dust and damage caused by rubbing between the transfer material P and the intermediate transfer belt 13, which roughens the surface of the intermediate transfer belt 13, the frictional force between the intermediate transfer belt 13 and the cleaning blade 31 tends to decrease in the paper passing area.

[0072] On the other hand, in the area outside the paper passing area, there is no paper dust supply and no contact between the transfer material P and the intermediate transfer belt 13, so the friction between the cleaning blade 31 and the intermediate transfer belt 13 tends to be higher than in the paper passing area. Therefore, a configuration in which the sheet member 45 is attached to the outside of the paper passing area including the boundary of the paper passing area is effective as a configuration for suppressing blade curling. Here, the definition of the paper passing area is as explained above, but for example, the width of the paper passing area based on the letter size in the image forming apparatus 100 of this embodiment is 216 mm.

[0073] Next, the width of the developing opening will be described. A developing container that contains toner is provided with a developing opening, and toner is supplied from the developing container to the developing roller 4 through the developing opening. The developing opening is provided so as to have a width longer than the developer application blade 7 in the longitudinal direction. Here, outside the developer application blade 7 in the longitudinal direction and inside the width of the developing opening, toner that is not charged to the normal charging polarity may exist because the developer application blade 7 cannot charge the toner. Since such toner is not charged to the normal charging polarity, it may be developed in an area where negative toner is not developed, and as a result, it may be supplied to the cleaning blade 31 as it is. That is, in the area facing the cleaning blade 31 that is inside the developing opening, toner that is not charged to the normal charging polarity may reach it.

[0074] On the other hand, in the area outside the developing aperture width, the possibility of toner supply is low, so the frictional force between the cleaning blade 31 and the intermediate transfer belt 13 is likely to be high compared to the area inside the developing aperture width. Therefore, a configuration in which the sheet member 45 is attached to the area outside the developing aperture width, including the boundary part of the developing aperture width, is effective as a configuration for suppressing blade curling. In the configuration of the image forming apparatus 100 of this embodiment, the developing aperture width in the longitudinal direction is 220 mm.

[0075] The exposable area in Fig. 11 will be described. As described above, the exposable area is an area where the photosensitive drum 1 can be exposed by the exposure means 11. From the viewpoint of toner supplyability, the exposable area is set to be wider in the longitudinal direction than the development opening width, which is the width through which toner can be supplied. In this embodiment, the longitudinal width of the exposure area involved in image formation is 226 mm.

[0076] Inside the exposable area, the potential of the photosensitive drum 1 fluctuates due to exposure, which may cause discharge between the photosensitive drum 1 and the intermediate transfer belt 13. If discharge products are generated on the surface of the photosensitive drum 1 and adhere to the intermediate transfer belt 13 due to the effect of such discharge, or if the surface of the intermediate transfer belt 13 is damaged by discharge, the friction coefficient μ of the intermediate transfer belt 13 may increase. Therefore, inside the exposable area, the friction force between the intermediate transfer belt 13 and the cleaning blade 31 is likely to be higher than that of the area outside the exposable area. On the other hand, the area outside the exposable area in the longitudinal direction is not affected by discharge. From the above, a configuration in which the sheet member 45 is attached to the area of ​​the cleaning blade 31 corresponding to the inside of the exposable area including the boundary of the exposable area in the longitudinal direction is effective as a configuration for suppressing blade curling.

[0077] In FIG. 11, the charging roller width refers to the width in the longitudinal direction of the roller portion of the charging roller 2 that contacts the photosensitive drum 1, and corresponds to the width in the longitudinal direction of the area of ​​the photosensitive drum 1 that can be charged by the charging roller 2. In this embodiment, the charging roller width in the longitudinal direction is 230 mm. In the longitudinal direction, the photosensitive drum 1 is discharged in the area inside the charging roller width. If discharge products are generated on the surface of the photosensitive drum 1 and adhere to the intermediate transfer belt 13 due to the effect of such discharge, or if the surface of the intermediate transfer belt 13 is damaged by the discharge, the friction coefficient μ of the intermediate transfer belt 13 may increase. Therefore, in the area inside the charging roller width, the friction force between the intermediate transfer belt 13 and the cleaning blade 31 is likely to be higher than in the area outside the charging roller width. On the other hand, the area outside the charging roller width in the longitudinal direction is not affected by the discharge. From the above, a configuration in which a sheet member 45 is attached in the region of the cleaning blade 31 corresponding to the inside of the charging roller width including the boundary portion of the charging roller width (i.e., the region in which the photosensitive drum 1 can be charged) in the longitudinal direction is effective as a configuration for suppressing blade curling.

[0078] 11, the frictional force between the intermediate transfer belt 13 and the cleaning blade 31 may vary depending on the position in the longitudinal direction due to the influence of various members. Therefore, by making the area reinforced with the sheet member 45 correspond to the longitudinal positions where the frictional force is different, it is possible to reduce the risk of the cleaning blade 31 turning over.

[0079] In the following embodiment 1 and modified examples 1 to 8, the position of the cleaning blade 31 on one end side of the cleaning blade 31 where the sheet member 45 is provided is between the first position and the second position. In the present embodiment, the sheet member 45 is also arranged in the same configuration on the other end side. Here, the first position is the position of the end (inner end) of the sheet member 45 arranged on the center side of the cleaning blade 31 in the longitudinal direction. The second position is the position of the end (outer end) of the sheet member 45 arranged on the end side of the cleaning blade 31 in the longitudinal direction. In addition, the second position is the position provided on the opposite side of the center of the cleaning blade 31 with the first position in between. In the configuration of each modified example, at least one of the first position and the second position is different.

[0080] 12(a) shows the configuration of Modification 1. In Modification 1, in the longitudinal direction, sheet member 45 is provided in an area from the boundary part of the image forming area (first position) to the boundary part of the exposable area (second position).

[0081] 12(b) shows the configuration of Modification 2. In Modification 2, in the longitudinal direction, sheet member 45 is provided in an area from the boundary part of the paper passing area (first position) to the boundary part of the exposable area (second position).

[0082] 12(c) shows the configuration of Modification 3. In Modification 3, in the longitudinal direction, sheet member 45 is provided in an area from the boundary part of the development opening width (first position) to the boundary part of the exposable area (second position).

[0083] 12(d) shows the configuration of Modification 4. In Modification 4, in the longitudinal direction, sheet member 45 is provided in an area from the boundary of the image forming area (first position) to the boundary of the charging roller width (second position).

[0084] 12(e) shows the configuration of Modification 5. In Modification 5, in the longitudinal direction, sheet member 45 is provided in an area from the boundary of the paper passage area (first position) to the boundary of the charging roller width (second position).

[0085] 12(f) shows the configuration of Modification 6. In Modification 6, in the longitudinal direction, sheet member 45 is provided in an area from the boundary portion of the developing opening width (first position) to the boundary portion of the charging roller width (second position).

[0086] 12(g) shows the configuration of Modification 7. In Modification 7, in the longitudinal direction, sheet member 45 is provided in an area from the boundary portion (first position) of the paper passing area to the boundary portion (second position) of end area 38 (open area).

[0087] 12(h) shows the configuration of Modification 8. In Modification 8, in the longitudinal direction, the sheet member 45 is provided in a region from the boundary portion (first position) of the developing opening width to the boundary portion (second position) of the end region 38 (open region).

[0088] The configurations of the above-mentioned modified examples 1 to 8 are summarized in the following Table 3. Note that the first position in the configuration of Example 1 is the boundary (edge) of the image forming area, and the second position is the boundary of the open area.

[0089] [Table 3]

[0090] FIG. 13 is a schematic diagram for explaining another configuration of the attachment position of the sheet member 45 in the first modification, and FIG. 14 is a schematic diagram for explaining another configuration of the attachment position of the sheet member 45 in the seventh modification.

[0091] Although the configurations in each modification are shown in Fig. 12, the present invention is not limited thereto, and it is sufficient that the sheet member 45 can be attached so as to include the areas of each member. That is, Figs. 12(a) to (f) of modification 1 to modification 6 show the areas where the sheet member 45 needs to be attached, respectively, in which the inner boundary is the image forming area, the paper passing area, and the development opening width, and the outer boundary is the exposure possible area and the charging roller width. Therefore, if the sheet member 45 is attached so as to include the areas of Figs. 12(a) to (f), it is possible to obtain the effects described in this embodiment. For example, in the case of modification 1, the actual attachment area of ​​the sheet member 45 may be as shown in Fig. 13.

[0092] On the other hand, in Modifications 7 and 8, in which the outer boundary portion extends up to the open region, the absence of the open region would cause the possibility of toner leakage, so the area in which sheet member 45 can be attached is from the edge of the open region to the inner area. Therefore, for example, in Modification 7, sheet member 45 may be attached as shown in Fig. 14. In all of the embodiments and modifications, at least a portion of sheet member 45 is provided outside the image forming region.

[0093] As described above, in the configurations of this embodiment and modified examples 1 to 8, the elastic modulus of the entire cleaning member 33 can be improved by reinforcing the region with high friction in the longitudinal direction where little toner is supplied with the sheet member 45. Also, by providing an open region where the sheet member 45 is not attached to the end of the cleaning blade 31, it is possible to suppress wear of the cleaning blade 31. This makes it possible to provide an embodiment of an image forming apparatus that can maintain cleaning performance while suppressing blade curling of the cleaning blade 31.

[0094] Example 2 Fig. 15 is a schematic diagram for explaining the configuration of Example 2. As shown in Fig. 15, Example 2 differs from Example 1 in that the attachment position of the sheet member 45 is the first surface 31e of the cleaning blade 31. In the following explanation, only the configuration different from Example 1 will be explained, and the same reference numerals will be used to denote the configuration common to Example 1, and the explanation will be omitted.

[0095] In this embodiment, the attachment position of the sheet member 45 in the longitudinal direction is in the same range as in the first embodiment, and therefore a description thereof will be omitted. However, unlike the first embodiment, the sheet member 45 is attached to the first surface opposite to the second surface 31f. Here, the first surface 31e is the surface facing the intermediate transfer belt 13, and if the sheet member 45 comes into contact with the intermediate transfer belt 13, there is a possibility that the cleaning performance will be affected. Therefore, in this embodiment, the sheet member 45 is not provided at the tip portion on the free end side of the cleaning blade 31 in the lateral direction so as not to affect the cleaning performance.

[0096] More specifically, in the configuration of this embodiment, the length of the first surface 31e of the cleaning blade 31 that comes into contact with the intermediate transfer belt 13 in the short direction (the length of the blade nip portion 37 in the belt conveying direction) is 100 μm. In light of this, an additional 100 μm is added to the aforementioned 100 μm length so as not to affect cleaning performance, and the sheet member 45 is attached at a position 200 μm away from the end on the free end side.

[0097] In this embodiment, similarly to the first embodiment, the thickness of the sheet member 45 may be 100 μm or more. However, if the sheet member 45 comes into contact with the intermediate transfer belt 13, the state of the intermediate transfer belt 13 may be changed, which may affect the cleaning performance and frictional force. Therefore, it is preferable to attach the sheet member 45 by controlling its thickness and the end positions in the short side direction so that the sheet member 45 does not come into contact with the intermediate transfer belt 13.

[0098] In this embodiment, the contact width between the intermediate transfer belt 13 and the cleaning blade (the width of the blade nip portion 37 in the belt conveying direction) is set to 100 μm. In this configuration, in view of the effect on cleaning performance, it is preferable to set the end position of the sheet member 45 in the short side direction at a position 200 μm or more away from the end on the free end side. On the other hand, the width of the blade nip portion 37 in the belt conveying direction is not limited to 100 μm, and is appropriately set depending on the configuration of the intermediate transfer belt 13 and the cleaning blade 31. Therefore, the end position of the sheet member 45 in the short side direction does not necessarily need to be set at a position 200 μm or more away from the end on the free end side. As described above, the end position of the sheet member 45 may be appropriately set so as not to contact the intermediate transfer belt 13.

[0099] As described above, in the configuration of this embodiment as well, it is possible to provide a configuration that maintains cleaning performance while suppressing the occurrence of blade curling of the cleaning blade 31, similarly to the first embodiment.

[0100] In the above-described embodiment, the cleaning blade 31 is reinforced against the intermediate transfer belt 13 of the color image forming apparatus, but the present invention is not limited to this configuration. For example, the cleaning blade having the configuration of this embodiment can be used as a cleaning member for the photosensitive drum of a monochrome image forming apparatus or a cleaning member for the photosensitive drum of a color image forming apparatus. In this case, the image carrier as the opposing member facing the cleaning blade is a rotatable photosensitive drum. Furthermore, the longitudinal direction in this embodiment is the longitudinal direction of the photosensitive drum perpendicular to the rotation axis direction of the photosensitive drum. Other configurations including various directions and the arrangement of each member are the same as those of this embodiment. By adopting the configuration of this embodiment, it is possible to obtain the same effect as that described in this embodiment with respect to the configuration of the cleaning blade that collects the toner remaining on the photosensitive drum. [Explanation of symbols]

[0101] 13 Intermediate transfer belt 31 Cleaning blade 33 Cleaning materials 34 Support member 45 Sheet material 38 End area

Claims

1. an image carrier that carries a toner image; a movable intermediate transfer member having an endless shape and in contact with the image carrier; A recovery unit for recovering toner remaining on the intermediate transfer body, a contact member that contacts the intermediate transfer body to collect toner remaining on the intermediate transfer body; A support member that supports the contact member; The recovery means having Equipped with The abutment member is The intermediate transfer member is provided so as to extend in a longitudinal direction of the contact member, the longitudinal direction being perpendicular to the moving direction of the intermediate transfer member, With respect to the short side direction of the abutting member, which is a direction perpendicular to the longitudinal direction, One end side is fixed to the support member, The other end is a free end that contacts the intermediate transfer body, and The abutment member is a sheet-like reinforcing member provided on one end side of the abutting member in the longitudinal direction, In the longitudinal direction, when the maximum area in which an image can be formed on a transfer material of the maximum size that can be used in an image forming apparatus is defined as the image forming area, The reinforcing member is a region outside the image forming region, the region being provided only in a region of the intermediate transfer body that corresponds to a region having a higher coefficient of friction than the image forming region; and The reinforcing member is the contact member is provided on one end side of the contact member, the contact member being located between a first position and a second position, the contact member being located on the inner side of the end of the contact member in the longitudinal direction, the first position is a position closer to the end of the contact member than a boundary between the image forming area and a non-image forming area in the longitudinal direction, The second position is a position provided on an opposite side of the center portion of the contact member with respect to the first position in the longitudinal direction, and is a position disposed between the first position and an end of the contact member.

1. An image forming apparatus comprising:

2. an exposure unit for exposing a surface of the image carrier to light, With respect to the longitudinal direction, the second position is a position corresponding to a boundary between an area configured to be able to expose the image carrier by the exposure unit and an area configured not to be able to expose the image carrier by the exposure unit.

2. The image forming apparatus according to claim 1,

3. a charging member for charging a surface of the image carrier, and the second position in the longitudinal direction corresponds to a boundary between an area configured to be capable of charging the image carrier by the charging member and an area configured not to be capable of charging the image carrier by the charging member; 2. The image forming apparatus according to claim 1,

4. When the width in the longitudinal direction of a transfer material of the maximum size that can be used in the image forming apparatus is defined as the paper passing area, the first position is a position corresponding to a boundary between the paper passing area and a non-paper passing area; 2. The image forming apparatus according to claim 1,

5. an exposure unit that exposes a surface of the image carrier, and the second position in the longitudinal direction corresponds to a boundary between an area configured to be able to expose the image carrier by the exposure unit and an area configured not to be able to expose the image carrier by the exposure unit; 5. The image forming apparatus according to claim 4.

6. a charging member for charging a surface of the image carrier, and the second position in the longitudinal direction corresponds to a boundary between an area configured to be capable of charging the image carrier by the charging member and an area configured not to be capable of charging the image carrier by the charging member; 5. The image forming apparatus according to claim 4.

7. a developer container for accommodating a toner; a developing member for developing the electrostatic latent image formed on the image carrier with a toner; having a developing unit capable of supplying toner to the developing member through an opening provided in the developing container, The first position corresponds to an end of the opening.

2. The image forming apparatus according to claim 1,

8. an exposure unit that exposes a surface of the image carrier, and the second position in the longitudinal direction corresponds to a boundary between an area configured to be able to expose the image carrier by the exposure unit and an area configured not to be able to expose the image carrier by the exposure unit; 8. The image forming apparatus according to claim 7,

9. 8. The image forming apparatus according to claim 7, further comprising a charging member for charging a surface of the image carrier, and the second position, with respect to the longitudinal direction, is a position corresponding to a boundary between an area configured to be capable of charging the image carrier by the charging member and an area configured not to be capable of charging the image carrier by the charging member.

10. The abutment member is a first surface facing an outer peripheral surface of the intermediate transfer body; a second surface opposite to the first surface; and having The reinforcing member is provided in a state of being attached to the second surface.

2. The image forming apparatus according to claim 1,

11. In the short-side direction, the length of the reinforcing member is shorter than the length of the abutting member.

2. The image forming apparatus according to claim 1,

12. The abutment member is a first surface facing an outer peripheral surface of the intermediate transfer body; a second surface opposite to the first surface; and having The reinforcing member is provided in a state of being attached to the first surface.

12. The image forming apparatus according to claim 11.

13. a rotatable image carrier that carries a toner image; A recovery unit for recovering toner remaining on the image carrier, a contact member that contacts the image carrier to collect toner remaining on the image carrier; A support member that supports the contact member; The recovery means having Equipped with The abutment member is The contact member is provided so as to extend in a longitudinal direction of the contact member, which is the direction of the rotation axis of the image carrier, and With respect to the short side direction of the abutting member, which is a direction perpendicular to the longitudinal direction, One end side is fixed to the support member, The other end is a free end that contacts the image carrier, and The abutment member is a sheet-like reinforcing member provided on one end side of the abutting member in the longitudinal direction, In the longitudinal direction, when the maximum area in which an image can be formed on a transfer material of the maximum size that can be used in an image forming apparatus is defined as the image forming area, The reinforcing member is the friction coefficient is higher than that of the image forming area, and the friction coefficient is higher than that of the image forming area. The reinforcing member is the contact member is provided on one end side of the contact member, the contact member being located between a first position and a second position, the contact member being located on the inner side of the end of the contact member in the longitudinal direction, the first position is a position closer to the end of the contact member than a boundary between the image forming area and a non-image forming area in the longitudinal direction, The second position is a position provided on an opposite side of the center portion of the contact member with respect to the first position in the longitudinal direction, and is a position disposed between the first position and an end of the contact member.

1. An image forming apparatus comprising:

Images