Developing device, process cartridge, and image forming apparatus

Abstract

To provide a technique that can prevent leakage of toner in an overlapping part of a blade and a seal member.SOLUTION: A developing device is provided in an image forming apparatus that forms an image on a recording material, and the developing device comprises: a frame body that has a storage part storing toner; a roller that is rotatably supported on the frame body in an opening for opening the storage part; a blade that is in contact with the roller to regulate a layer thickness of toner carried on the roller; and a seal member that has a first portion compressed between the frame body and a surface of the blade on an opposite side of a surface in contact with the roller, and a second portion continuous with the first portion and compressed between the roller and the frame body. The frame body has a bearing surface of the seal member, and a projection projecting from the bearing surface. The projection is arranged in contact with a boundary between the first portion and the second portion of the seal member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a developing device, a process cartridge, and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art In electrophotographic image forming apparatuses, a so-called process cartridge system is often adopted as a configuration excellent in usability, and some process cartridges include a developing unit having a developing means.

[0003] The developing unit has, for example, a toner storage chamber for storing toner, a developing roller for carrying the toner, a blade for regulating the toner layer thickness on the developing roller, and a number of sealing members for preventing the toner from leaking out of the developing unit. Some of the sealing members are arranged in the gaps between the developing container at both ends of the developing unit in the longitudinal direction, the back surface of the blade, and the peripheral surface of the developing roller (also called end sealing members). The surface of these sealing members that rub against the developing roller is made of felt, pile fabric, or the like, and is flexible. The sealing members are generally arranged so as to overlap the blade in a state where they are compressed and deformed by a predetermined amount, and the repulsive force due to the compression and deformation of the sealing members is used to ensure sealing.

[0004] Here, in a configuration in which the blade overlaps the seal member, a step (hereinafter referred to as an "overlap step") is formed that extends outward in the axial direction of the developing roller. In the vicinity of this overlap step, the developing roller and the seal member do not make sufficient contact with each other, and the contact pressure decreases. For this reason, there is a concern that some of the toner on the developing roller that has not been able to pass through the blade may leak out of the developing unit by running along the longitudinal outer side of the blade and near the overlap step.

[0005] In response to this, Patent Document 1 proposes the following configuration for a step portion that occurs when an entrance seal that is disposed in the longitudinal direction to prevent toner leakage while collecting residual toner on the developing roller into the developing unit and a sealing member overlap each other: That is, toner is prevented from leaking by providing toner blocking portions that extend in the rotation direction of the developing roller along the sealing member at both ends of the entrance seal. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-172717 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, when attempting to apply the inlet seal described in Patent Document 1 to a blade, the following problem occurs. When toner blocking portions are provided at both ends of the blade, the blade is in counter-contact with the developing roller, so that the tip of the toner blocking portion is in contact with the surface of the developing roller. If this state continues for a long time, cracks are likely to occur on the surface of the developing roller, and there is a risk that the surface of the developing roller will be scraped off. If the surface of the developing roller is scraped off, a gap will be created at the contact point with the blade or the seal member, and there is a concern that toner will leak from this gap.

[0008] An object of the present invention is to provide a technique capable of suppressing toner leakage from an overlapping portion between a blade and a seal member. [Means for solving the problem]

[0009] In order to solve the above problems, the developing device of the present invention comprises: A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between the frame and a surface of the blade opposite to a surface that contacts the roller, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: The frame has a seating surface for the seal member and a protrusion protruding from the seating surface, The protrusion is disposed so as to contact the boundary between the first portion and the second portion of the seal member. In order to solve the above problems, the developing device of the present invention comprises: A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between the frame and a surface of the blade opposite to a surface that contacts the roller, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: the sealing member has an elastic layer on a side in contact with the frame; The elastic layer includes a first elastic portion having a first hardness and a second elastic portion having a second hardness higher than the first hardness, The second elastic portion is arranged so as to overlap the boundary between the first portion and the second portion of the sealing member when viewed in a direction perpendicular to the rotation axis of the roller. In order to solve the above problems, the developing device of the present invention comprises: A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between the frame and a surface of the blade opposite to a surface that contacts the roller, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: the sealing member has a pile yarn layer on a side in contact with the roller and the blade, the pile yarn layer includes a first pile yarn layer that contacts the roller and the blade with a first contact pressure, and a second pile yarn layer that contacts the roller and the blade with a second contact pressure higher than the first contact pressure, The second pile yarn layer is characterized in that it is arranged so as to overlap the boundary between the first and second portions of the sealing member when viewed in a direction perpendicular to the rotation axis of the roller. In order to solve the above problems, the process cartridge of the present invention comprises: A process cartridge detachably mountable to a main body of an image forming apparatus, a photoreceptor on which an electrostatic image is formed; a developing device of the present invention for developing an electrostatic image formed on the photoreceptor; The present invention is characterized by comprising: In order to solve the above problems, the image forming apparatus of the present invention comprises: An image forming apparatus for forming an image on a recording material, The present invention is characterized by comprising the developing device of the present invention or the process cartridge of the present invention. Effect of the Invention

[0010] According to the present invention, it is possible to suppress toner leakage from the overlapping portion between the blade and the seal member. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a main part of a developing unit according to a first embodiment of the present invention; [Diagram 2] Schematic diagram showing the main part of the end seal of Example 1 [Diagram 3] Schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. [Figure 4] Schematic cross-sectional view of a process cartridge according to a first embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram showing a developing frame from the photosensitive member side with the developing roller removed in the first embodiment; [Figure 6] FIG. 11 is a schematic diagram showing a main part of a developing unit according to a second embodiment of the present invention; [Figure 7] FIG. 11 is a schematic diagram showing a main part of a developing unit according to a third embodiment of the present invention; [Figure 8] Schematic diagram showing the main part of the end seal of Example 4. [Figure 9] Schematic diagram showing the main part of the toner of Example 5 [Figure 10] Schematic diagram of cross-section of toner observed by STEM [Figure 11] Schematic diagram showing how to measure a convex shape DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <Example 1> Hereinafter, the embodiment 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 embodiment may be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, the scope of the present invention is not limited to the following embodiment.

[0013] Here, in the present invention, a process cartridge is a cartridge in which an electrophotographic photosensitive member (hereinafter, photosensitive member) and at least a developing means as a process means acting on the photosensitive member are integrated into a cartridge, and the cartridge is detachable from the main body of an electrophotographic image forming apparatus. Also, an electrophotographic image forming apparatus (hereinafter, image forming apparatus) is an apparatus that forms an image on a recording material (recording medium) using an electrophotographic image forming method. Examples of image forming apparatuses include copying machines, printers (laser beam printers, LED printers, etc.), facsimile machines, word processors, and multifunction machines (multifunction printers) that combine these devices. Also, in the present invention, an image forming apparatus is an apparatus in which either a plurality of developing devices or a plurality of process cartridges are detachably attached to the main body of the image forming apparatus.

[0014] [Electrophotographic image forming device] The overall configuration of an image forming apparatus using an electrophotographic image forming method (electrophotographic process) according to an embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a schematic cross-sectional view of an image forming apparatus 100 according to this embodiment.

[0015] Image forming apparatus 100 has multiple image forming units, namely, first, second, third and fourth image forming units SY, SM, SC and SK for forming images of each of the colors yellow (Y), magenta (M), cyan (C) and black (K), respectively.

[0016] In this embodiment, the image forming apparatus 100 has four photosensitive drums 1 (1Y, 1M, 1C, 1K) as image carriers. The photosensitive drums 1 (1Y, 1M, 1C, 1K) rotate in the direction of arrow A in Fig. 3. Charging rollers 2 (2Y, 2M, 2C, 2K) and a scanner unit (exposure device) 3 are arranged around the photosensitive drums 1 (1Y, 1M, 1C, 1K).

[0017] Here, the charging roller 2 (2Y, 2M, 2C, 2K) is a charging means for uniformly charging the surface of the photosensitive drum 1 (1Y, 1M, 1C, 1K). The scanner unit 3 is an exposure means for irradiating the photosensitive drum 1 with laser light based on image information to form an electrostatic image (electrostatic latent image). Around the photosensitive drum 1 (1Y, 1M, 1C, 1K), a developing device (hereinafter, developing unit) 4 (4Y, 4M, 4C, 4K) and a cleaning blade 6 (6Y, 6M, 6C, 6K) as a cleaning means are arranged. The transfer residual toner (waste toner) remaining on the photosensitive drum 1 (1Y, 1M, 1C, 1K) is cleaned by the cleaning blade 6 (6Y, 6M, 6C, 6K) and is stored in a removed developer storage section (hereinafter, waste toner storage section) 14a (14aY, 14aM, 14aC, 14aK).

[0018] Furthermore, an intermediate transfer belt 5 serving as an intermediate transfer body for transferring the toner images on the photosensitive drums 1 onto a recording material 12 is disposed opposite the four photosensitive drums 1 (1Y, 1M, 1C, 1K).

[0019] In this embodiment, the developing units 4 (4Y, 4M, 4C, 4K) each contain a non-magnetic one-component developer, i.e., toner T (TY, TM, TC, TK), as the developer. In this embodiment, the developing units 4 (4Y, 4M, 4C, 4K) perform contact development by bringing developing rollers 17 (17Y, 17M, 17C, 17K) as developer carriers into contact with the photosensitive drums 1 (1Y, 1M, 1C, 1K), respectively.

[0020] Further, each of the image forming stations SY, SM, SC, and SK is formed with a photosensitive unit 13 (13Y, 13M, 13C, and 13K) so as to have a photosensitive drum 1, a charging roller 2, a cleaning blade 6, and a waste toner storage section 14a, respectively.

[0021] Furthermore, in this embodiment, the developing unit 4 and the photosensitive unit 13 are integrated into a cartridge to form a process cartridge 7 (7Y, 7M, 7C, 7K). The process cartridge 7 is detachably mountable to the main body of the image forming apparatus 100 via mounting means such as a mounting guide and a positioning member (not shown) provided in the image forming apparatus 100.

[0022] In this embodiment, the process cartridges 7 for each color all have the same shape, and the process cartridges 7 for each color contain toner T (TY, TM, TC, TK) of each color, yellow, magenta, cyan, and black, respectively. That is, the configurations and operations of the first to fourth image forming units SY, SM, SC, and SK are substantially the same except for the different colors of toner used. Therefore, in the following description, unless a particular distinction is required, the suffixes Y, M, C, and K given to the reference characters in FIG. 3 to indicate that the element is provided for one of the colors will be omitted and the description will be given generally.

[0023] The intermediate transfer belt 5 contacts all the photosensitive drums 1 and rotates in the direction of the arrow B in Fig. 3. The intermediate transfer belt 5 is stretched over a plurality of support members (a drive roller 51, a secondary transfer opposing roller 52, and a driven roller 53).

[0024] Four primary transfer rollers 8 (8Y, 8M, 8C, 8K) are arranged side by side on the inner peripheral surface side of the intermediate transfer belt 5 so as to face each photosensitive drum 1. A secondary transfer roller 9 is provided as a transfer means.

[0025] [Image formation process] When forming an image, first, the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2. Next, the charged surface of the photosensitive drum 1 is scanned and exposed by a laser beam corresponding to image information emitted from a scanner unit 3, and an electrostatic image corresponding to the image information is formed on the photosensitive drum 1. Next, the electrostatic image formed on the photosensitive drum 1 is developed into a toner image (developer image) by a developing unit 4. The toner image formed on the photosensitive drum 1 is transferred (primary transfer) onto an intermediate transfer belt 5 by the action of a primary transfer roller 8.

[0026] For example, when a full-color image is formed, the above-mentioned process is performed in sequence in the first to fourth image forming stations SY, SM, SC, and SK, and the toner images of each color are primarily transferred onto the intermediate transfer belt 5 so as to be sequentially superimposed on each other. Thereafter, the recording material 12 is conveyed to the secondary transfer section in synchronization with the movement of the intermediate transfer belt 5. Then, the four color toner images on the intermediate transfer belt 5 are collectively transferred (secondarily transferred) onto the recording material 12 by the action of the secondary transfer roller 9 that is in contact with the intermediate transfer belt 5 via the recording material 12.

[0027] The recording material 12 onto which the toner image has been transferred is transported to a fixing device 10 serving as a fixing means, where the toner image is fixed to the recording material 12 by applying heat and pressure to the recording material 12 .

[0028] Any primary transfer residual toner remaining on the photosensitive drum 1 after the primary transfer process is removed by a cleaning blade 6. In addition, any secondary transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer process is removed by an intermediate transfer belt cleaning device 11.

[0029] The image forming apparatus 100 is also capable of forming a monochromatic or multi-color image by using at least one desired image forming unit among the plurality of image forming units.

[0030] [Process cartridge] 4 and 5, the overall configuration of the process cartridge 7 mounted in the image forming apparatus 100 of this embodiment will be described. Fig. 4 is a schematic cross-sectional view of the process cartridge 7. Fig. 5 is a front view of the developing unit 4 as viewed from the photosensitive drum 1 side with the developing roller 17 removed.

[0031] The developing unit 4 has a developing frame 18 that supports various elements in the developing unit 4. The developing unit 4 is provided with a developing roller 17 that contacts the photosensitive drum 1 and rotates in the direction of arrow D (counterclockwise) in FIG. 4. The developing roller 17 is rotatably supported by the developing frame 18 via bearings at both ends in its longitudinal direction (rotational axis direction). In the following description, the longitudinal direction refers to the rotational axis direction (axial direction) of the developing roller 17.

[0032] The developing unit 4 (developing frame 18) has a developer storage chamber (hereinafter, toner storage chamber) 18a, a developing chamber 18b in which the developing roller 17 is disposed, and an opening 18c that opens the developing chamber 18b. The developing roller 17 is supported by the developing frame 18 so as to be rotatable at the opening 18c of the developing chamber 18b. Here, the toner storage chamber 18a and the developing chamber 18b constitute a toner storage section in the developing unit 4.

[0033] In the developing chamber 18b, a toner supply roller 20 as a developer supply member that contacts the developing roller 17 and rotates in the direction of the arrow E in FIG. 4, and a plate-shaped developing blade 21 as a regulating member are disposed. Here, the developing blade 21 regulates the amount of the toner carried by the developing roller 17. It abuts against the peripheral surface of the developing roller 17 so as to regulate the layer thickness.

[0034] The developing frame 18 is provided with seating surfaces 31 on both ends in the longitudinal direction of the developing roller 17 so as to sandwich the opening 18c of the developing chamber 18b, and end seal members (hereinafter, end seals) 30 are attached and fixed to the seating surfaces 31. The end seals 30 are flexible members whose surfaces are made of felt, pile made of woven fibers, electrostatic flocking, or the like.

[0035] The developing roller 17 is attached to the developing frame 18 via the end seal 30 installed on the developing frame 18 as described above. As a result, the end seal 30 is compressed and disposed in the gap between the developing blade 21 and the developing frame 18, and in the gap between the developing roller 17 and the developing frame 18 that is continuous with the gap in the longitudinal direction of the developing roller 17.

[0036] With this configuration, it is possible to prevent the toner in the developing chamber 18b from leaking to the outside. The details of the sealing configuration of the developing unit 4 will be described later.

[0037] Further, the toner storage chamber 18a of the developing frame 18 is provided with an agitating member 23 for agitating the stored toner T and transporting the toner to the toner supply roller 20. The rotation of the agitating member 23 enables the toner to be transported from the toner storage chamber 18a to the developing chamber 18b.

[0038] The developing unit 4 is connected to the photosensitive unit 13 so as to be freely rotatable about a fitting shaft (not shown) fixedly supported by the cleaning frame 14. The developing unit 4 is also biased by a pressure spring (tension spring) (not shown). Therefore, during image formation, the developing unit 4 rotates about the fitting shaft (not shown) and the photosensitive drum 1 and the developing roller 17 come into contact with each other.

[0039] [Photoconductor unit] The photosensitive unit 13 has a cleaning frame 14 that supports various elements in the photosensitive unit 13. The photosensitive drum 1 is rotatably attached to the cleaning frame 14 via a bearing member in the direction of arrow A in FIG.

[0040] Further, a charging roller bearing 15 is attached to the cleaning frame 14 along a line passing through the center of rotation of the charging roller 2 and the center of rotation of the photosensitive drum 1. Here, the charging roller bearing 15 is attached so as to be movable in the direction of arrow C in Fig. 4. The charging roller 2 is rotatably attached to the charging roller bearing 15. The charging roller bearing 15 is urged toward the photosensitive drum 1 by a charging roller pressure spring 16 serving as urging means.

[0041] The cleaning blade 6 is formed integrally with an elastic member 6a for removing residual toner (waste toner) remaining on the surface of the photosensitive drum 1 after the primary transfer, and a support member 6b for supporting the elastic member 6a. The residual toner (waste toner) removed from the surface of the photosensitive drum 1 by the cleaning blade 6 falls in the direction of gravity through a space formed by the cleaning blade 6 and the cleaning frame 14, and is stored in the waste toner storage section 14a.

[0042] [Developing unit seal configuration] 1, 2, 4, and 5, the toner seal configuration of the developing frame 18, which is the main part in this embodiment, will be described. Note that in this embodiment, the seal configuration on one end side in the longitudinal direction of the developing unit 4 will be mainly described, but the other end side has the same configuration.

[0043] FIG. 1(a) shows a seat surface for attaching an end seal 30 of the developing frame 18 shown in FIG. FIG. 1(b) is a perspective view of the end seal seat surface 31, near the area where the end seal 30 and the developing blade 21 overlap, viewed obliquely with the developing roller 17 removed. FIG. 1(b) is a view showing a state where the end seal 30 is omitted from the configuration shown in FIG. 1(a). FIG. 1(c) is a side view of the configuration shown in FIG. 1(a) with the developing roller 17 attached, viewed from the axial direction of the developing roller. FIG. 1(d) is a detailed view of the H1 portion shown in FIG. 1(c).

[0044] 4 and 5, the developing unit 4 has a developing chamber 18b for supplying the toner contained in the toner containing chamber 18a to the developing roller 17. The developing roller 17 and the developing blade 21 are disposed in an opening 18c of the developing chamber 18b.

[0045] The developing blade 21 in this embodiment is configured by joining a blade portion 21a made of a stainless steel plate or a phosphorus bronze plate to a support plate 21b made of a steel plate. The support plate 21b is fixed to the developing frame 18 with a screw 22.

[0046] As shown in FIG. 1, end seal seating surfaces 31 are provided in a generally concave arc shape at both longitudinal ends of the developing chamber 18b, and end seals 30 are disposed on the end seal seating surfaces 31. A portion of the end seal 30 overlaps with the developing blade 21 in the longitudinal direction. The end seal 30 is compressed by the circumferential surface of the developing roller 17 and the back surface of the developing blade 21 (the surface of the developing blade 21 opposite to the surface that abuts against the developing roller 17). At this time, the area formed by the tip 21d of the developing blade 21 and the end seal 30 (area J shown in FIG. 1(d)) overlaps and forms a step.

[0047] 1, a protrusion (convex portion) 32 is disposed on the end seal seating surface 31 in the vicinity of an overlapping step J where the tip 21d of the developing blade 21 and the end seal 30 come into contact. In this embodiment, the protrusion 32 is formed in a rectangular shape. The protrusion 32 is disposed at a position facing the tip 21d of the developing blade 21 in the thickness direction of the developing blade 21 so that the gap generated at the overlapping step J is narrowed.

[0048] FIG. 2(a) is a schematic diagram showing the positional relationship of the developing blade 21, the end seal 30, the end seal seating surface 31, and the protrusion 32 when viewed in a direction (radial direction) perpendicular to the rotation axis of the developing roller 17. FIG. 2(b) is a schematic cross-sectional view of the developing blade 21, the end seal 30, the end seal seating surface 31, and the protrusion 32 in the direction of the arrow X in FIG. 2(a) at a position corresponding to the portion H1 shown in FIG. 1(c). As shown in FIG. 2, the end seal 30 has a first portion P1 compressed in a first gap between the developing blade 21 and the end seal seating surface 31 of the developing frame 18, and a second portion P2 compressed in a second gap between the developing roller 17 and the end seal seating surface 31 of the developing frame 18. In FIG. 2(a), the end seal 30 is indicated by a broken line, the first portion P1 is indicated by hatching from the upper right to the lower left, and the second portion P2 is indicated by hatching from the upper left to the lower right.

[0049] As shown in FIG. 2(a), the first portion P1 and the second portion P2 of the end seal 30 are continuous in the circumferential direction around the rotation axis of the developing roller 17 and in the longitudinal direction of the developing roller 17. The boundary between the first portion P1 and the second portion P2 includes a first boundary BL extending along the rotation axis of the developing roller 17 and a second boundary BS extending along the circumferential direction around the rotation axis of the developing roller 17. The first boundary BL extends outward in the longitudinal direction from an inner end portion close to or in contact with the developing chamber 18b, and connects to the second boundary BS at an outer end portion. The second boundary BS extends in the circumferential direction along the rotation direction of the developing roller 17 from the outer end portion of the first boundary BL.

[0050] The protrusion 32 is disposed on the end seal 30 so as to contact the first boundary BL and the second boundary BS. As a result, the end seal 30 has a region compressed between the protrusion 32 and the developing blade 21 in the first portion P1 in the vicinity of the first boundary BL and the second boundary BS, and a region compressed between the protrusion 32 and the developing blade 21 in the second portion P2 in the vicinity of the first boundary BL and the second boundary BS. and a region compressed between the protrusion 32 and the developing roller 17 in portion P2. The protrusion 32 protrudes from the end seal seating surface 31 so as to make the contact pressure of the end seal 30 against the developing roller 17 higher in the region near the first boundary BL and the second boundary BS (near the boundary) than in the region outside the vicinity of the boundary. The end seal 30 is compressed so that the thickness of the portion in contact with the protrusion 32 is smaller than the thickness of the portion not in contact with the protrusion 32.

[0051] The vicinity of the boundary where the contact pressure in the end seal 30 is increased may be defined as including an area in the first portion P1 that is compressed between the protrusion 32 and the surface of the developing blade 21 opposite to the surface that contacts the developing roller 17. The vicinity of the boundary may also be defined as including an area in the second portion P2 that is compressed between the protrusion 32 and the developing roller 17. The vicinity of the boundary may also be defined as including at least the first boundary BL and a part of the second boundary BS (the side that connects to the first boundary BL).

[0052] 2(b), the first portion P1 of the end seal 30 has an area P1r that sandwiches the tip portion 21d of the developing blade 21 between the first portion P1 and the developing roller 17. The second portion P2 of the end seal 30 has an area P2r that faces the tip surface of the tip portion 21d of the developing blade 21. The vicinity of the boundary where the contact pressure in the end seal 30 is increased may be defined as including the area P1r and the area P2r.

[0053] As a specific example of the shape of the protrusion 32, in this embodiment, the height h of the protrusion 32 from the seating surface 31 is about 0.5 to 1.0 mm. The rectangular shape of the protrusion 32 is a square with one side W of 2 mm. The protrusion 32 is disposed closest to the developing chamber 18b on the seating surface 31 in the longitudinal direction. The protrusion 32 is disposed so as to have a portion OL that overlaps the tip 21d of the blade by at least 1 mm in the lateral direction (circumferential direction) perpendicular to the longitudinal direction.

[0054] The above dimensions are merely an example and should be appropriately set depending on the device configuration, and are not limited to the above values.

[0055] The end seal 30 is fixed to the end seal seat 31 including the protrusion 32 via double-sided tape or the like. At this time, the protrusion 32 is partially or entirely covered by the end seal 30. Therefore, the end seal 30 varies in ease of being locally compressed in the portion covering the protrusion 32. Specifically, the portion of the end seal 30 covering the protrusion 32 is less easily compressed than other portions. Therefore, the end seal 30 can locally increase the repulsive force in the portion covering the protrusion 32.

[0056] This makes it possible to relatively increase the contact pressure of the end seal 30 against the developing roller 17 in the vicinity of the overlapping step J, and to narrow the gap occurring at the overlapping step J compared to the conventional configuration without the protrusion 32. Therefore, it is possible to suppress leakage of toner through the gap occurring at the overlapping step J.

[0057] Here, we will explain the reason why the contact pressure of the end seal 30 is increased only at the overlapping step J, and not increased in areas other than the overlapping step J. If the contact pressure were increased to areas other than the overlapping step J, friction due to rubbing with the developing roller 17 would become too large. If this friction is too large, cracks are more likely to occur on the surface of the developing roller 17, and there is a risk that the surface of the developing roller 17 may be scraped off. Furthermore, if the friction is too large, the surface temperature of the developing roller 17 will rise, and there is a risk that toner that has penetrated the end seal 30 will melt and be fused onto the end seal 30. These phenomena will cause a gap to form between the developing roller 17 and the end seal 30, causing toner to leak out. Furthermore, if the friction is too large, the developing roller 17 will become too hot, and there is a risk that the surface of the developing roller 17 will become too hot. The torque required to drive the roller 17 becomes large, and as a result, it becomes necessary to increase the capacity of the drive motor for driving the entire developing unit, resulting in increased costs. For these reasons, the protrusions 32 are provided to locally increase the contact pressure so as to simultaneously suppress toner leakage through the gaps generated in the overlapping steps J without excessively increasing the friction between the end seal 30 and the developing roller 17.

[0058] <Example 2> An image forming apparatus according to a second embodiment of the present invention will be described with reference to Fig. 6. The basic configuration of the image forming apparatus of this embodiment is the same as that of the image forming apparatus of the first embodiment, and components similar to those of the first embodiment are given the same reference numerals and their description will be omitted. Items in this embodiment that are not particularly described here are the same as those of the first embodiment.

[0059] Fig. 6(a) is a perspective view of the vicinity of the end seal seating surface 31 in this embodiment when viewed obliquely without the end seal 30. Fig. 6(b) is a side view of the vicinity of the end seal 30 when viewed from the axial direction of the developing roller. Fig. 6(c) is a schematic perspective view showing the detailed configuration of the end seal 30 in this embodiment.

[0060] As shown in FIG. 6(a), this embodiment has a configuration in which the protrusion portion 32 described in the first embodiment is omitted, and as shown in FIGS. 6(b) and 6(c), the configuration of the end seal 30 differs from that of the first embodiment.

[0061] The end seal 30 will be described in more detail. As shown in FIG. 6(c), the end seal 30 is composed of a surface layer 30a, a base layer 30c, and an adhesive layer 30b that bonds the surface layer 30a and the base layer 30c. The surface layer 30a has a base fabric 30a2 and pile yarns 30a1 raised from the base fabric 30a2. The base layer 30c is a cushion layer (elastic layer) made of an elastic body. The material of the base layer 30c is a foam of a synthetic resin such as polyurethane.

[0062] The pile yarn 30a1 may be made of the following materials: synthetic fibers (chemical fibers) such as polyethylene, polypropylene, polyester, nylon, acrylic fiber, and polyethylene terephthalate; semi-synthetic fibers such as rayon; natural fibers such as cotton; or combinations or twisted fibers of these. In this embodiment, a blend of acrylic resin and cotton is used as the material for the pile yarn 30a1. Synthetic fibers are generally strong, which contributes to improving the durability of the end seal 30. Acrylic fibers are flexible, which provides good sliding properties against the developing roller 17. The acrylic fibers referred to here are synthetic fibers whose main raw material is acrylonitrile.

[0063] In this embodiment, the hardness of a portion of the base layer 30c (area K shown in FIG. 6(c)) is increased. That is, the base layer 30c as an elastic layer includes an area that is not increased in hardness as a first elastic portion having a first hardness, and a high-hardness portion K as a second elastic portion having a second hardness higher than the first hardness. As shown in FIG. 6(b), this high-hardness portion K is disposed at a position facing the tip portion 21d of the developing blade 21 in the thickness direction of the developing blade 21. That is, the high-hardness portion K as the second elastic portion is disposed so as to overlap the first boundary BL and the second boundary BS when viewed in a direction perpendicular to the rotation axis of the developing roller 17 (radial direction). As a result, the vicinity of the first boundary BL and the second boundary BS in the end seal 30 includes an area in the first portion P1 that overlaps with the high hardness portion K, and an area in the second portion P2 that overlaps with the high hardness portion K, when viewed in a direction perpendicular to the rotational axis of the developing roller 17. The first portion P1, the second portion P2, the first boundary BL, and the second boundary BS in the second embodiment are similar to those in the first embodiment (see FIG. 2).

[0064] By providing the high hardness portion K, the region near the first boundary BL and the second boundary BS (the region near the boundary ), the contact pressure of the end seal 30 against the developing roller 17 becomes higher than the contact pressure in the area outside the vicinity of the boundary.

[0065] The vicinity of the boundary where the contact pressure in the end seal 30 of this embodiment is increased may include an area in the first portion P1 that overlaps with the high hardness portion K, and an area in the second portion P2 that overlaps with the high hardness portion K, when viewed in a direction perpendicular to the rotational axis of the developing roller 17.

[0066] As a means for changing the hardness of the high hardness portion K to a hardness higher than that of other portions, the foaming rate of the material of only the high hardness portion K may be reduced, or only the high hardness portion K may be changed to another high hardness material.

[0067] A specific method for locally increasing the hardness is, for example, to set the foaming ratio of the high hardness portion K to about half that of the other portions of the base layer 30c. In addition, an example of changing to a high hardness material is to use polyurethane for the other portions of the base layer 30c, while using foamed polyethylene for the high hardness portion K.

[0068] Furthermore, the formation range of the high hardness portion K in the base layer 30c, its arrangement in the longitudinal direction, and its arrangement in the lateral direction may be similar to those of the protrusions 32 in the first embodiment.

[0069] It should be noted that the above-mentioned method of locally increasing hardness and dimension settings are merely examples, and an appropriate method should be used and appropriately set depending on the device configuration, and are not limited to the above-mentioned methods and numerical values.

[0070] By having the high hardness portion K in the base layer 30c as described above, the end seal 30 is locally compressed to a different extent in the portion where the high hardness portion K is provided. Specifically, the portion where the high hardness portion K is provided in the end seal 30 is less easily compressed than other portions. Therefore, the end seal 30 can locally increase the repulsive force in the portion where the high hardness portion K is provided.

[0071] As a result, similarly to the first embodiment, the contact pressure of the end seal 30 against the developing roller 17 can be relatively increased in the vicinity of the overlapping step J, and the gap occurring at the overlapping step J can be narrowed compared to the conventional configuration without the high hardness portion K. Therefore, the leakage of toner through the gap occurring at the overlapping step J can be suppressed.

[0072] <Example 3> An image forming apparatus according to a third embodiment of the present invention will be described with reference to Fig. 7. In this embodiment, the basic configuration of the image forming apparatus is the same as in the first embodiment, and the detailed configuration of the end seal is also the same as in the second embodiment, so the same components as in the first and second embodiments are given the same reference numerals and their description will be omitted. Items in this embodiment that are not particularly described here are the same as in the above embodiments.

[0073] Fig. 7(a) is a perspective view of the area where the end seal 30 and the developing blade 21 overlap in this embodiment, as viewed obliquely. Fig. 7(b) is a diagram showing a detailed configuration of the end seal 30 in this embodiment. Fig. 7(c) is a schematic diagram showing a part of the configuration shown in Fig. 7(b) as viewed from the thickness direction of the end seal 30.

[0074] In this embodiment, the pile yarn 30a1 except for a part of the area (area L shown in FIG. 7) is made up of a first pile yarn layer that contacts the developing roller 17 or the developing blade 21 with a first contact pressure. Area L is made up of a second pile yarn layer that contacts the developing roller 17 or the developing blade 21 with a second contact pressure that is higher than the first contact pressure. Specifically, the pile yarn alone applied to area L The number of pile yarns per unit area in the end seal 30 is greater than the same number in other areas. That is, the pile yarn layer on the side of the end seal 30 that contacts the developing roller 17 includes at least two areas with different numbers of pile yarns per unit area. Specifically, the pile yarn layer includes areas other than the area L as a first density part in which the number of pile yarns per unit area is a first number, and the area L as a second density part in which the number of pile yarns per unit area is a second number greater than the first number.

[0075] As shown in Fig. 7(a), this region L is disposed at a position facing the tip portion 21d of the developing blade 21 in the thickness direction of the developing blade 21. That is, the region L as the second density portion is disposed so as to overlap the first boundary BL and the second boundary BS when viewed in a direction perpendicular to the rotation axis of the developing roller 17 (radial direction). As a result, the vicinity of the first boundary BL and the second boundary BS in the end seal 30 includes a region overlapping the region L in the first portion P1 and a region overlapping the region L in the second portion P2 when viewed in a direction perpendicular to the rotation axis of the developing roller 17. The first portion P1, the second portion P2, the first boundary BL, and the second boundary BS in the third embodiment are also similar to those in the first embodiment (see Fig. 2).

[0076] By providing the region L, the contact pressure of the end seal 30 against the developing roller 17 in the region near the first boundary BL and the second boundary BS (near the boundary) becomes higher than the contact pressure in the region outside the vicinity of the boundary.

[0077] The vicinity of the boundary where the contact pressure in the end seal 30 of this embodiment is increased may include an area in the first portion P1 that overlaps with area L and an area in the second portion P2 that overlaps with area L when viewed in a direction perpendicular to the rotational axis of the developing roller 17.

[0078] Specifically, in this embodiment, the number of pile yarns per unit area in the areas other than the area L is 1000 / inch 2 The number of pile yarns per unit area in area L is about 2000 / inch 2 In this embodiment, the pile yarn has a thickness (diameter) of about 20 um and a length of about 1.5 mm.

[0079] Moreover, the formation range of the region L, the arrangement in the longitudinal direction, and the arrangement in the lateral direction may be similar to those of the protrusion 32 in the first embodiment.

[0080] The above dimensions are merely an example and should be appropriately set depending on the device configuration, and are not limited to the above values.

[0081] Since the number of pile yarns in the region L is greater than the number of pile yarns in the other regions, the apparent rigidity is relatively high. Therefore, when the end seal 30 comes into contact with the developing roller 17, the repulsive force in the region L can be relatively increased.

[0082] As a result, similarly to the first and second embodiments, the contact pressure of the end seal 30 against the developing roller 17 can be relatively increased in the vicinity of the overlapping step J, and the gap occurring at the overlapping step J can be narrowed compared to the conventional configuration without the region L. Therefore, the leakage of toner through the gap occurring at the overlapping step J can be suppressed.

[0083] <Example 4> An image forming apparatus according to a fourth embodiment of the present invention will be described with reference to Fig. 8. In this embodiment, the basic configuration of the image forming apparatus is the same as in the first embodiment, and the detailed configuration of the end seal is also the same as in the second embodiment, so the same components as in the first and second embodiments are given the same reference numerals and their description will be omitted. Items in this embodiment that are not particularly described here are the same as in the above embodiments.

[0084] FIG. 8 is a schematic diagram (FIG. 7(c)) showing part of the configuration of the end seal 30 described in the third embodiment, which corresponds to the end seal 30 in this embodiment.

[0085] In this embodiment, the apparent rigidity of the region L described in the third embodiment is realized by increasing the thickness of each pile thread, not by increasing the number of pile threads. That is, the pile thread layer on the side of the end seal 30 that contacts the developing roller 17 or the developing blade 21 includes a region other than the region L as a first pile thread portion (first pile thread layer) in which pile threads of a first thickness are arranged, and a region L as a second pile thread portion (second pile thread layer) in which pile threads of a second thickness thicker than the first thickness are arranged. The region L as the second pile thread portion is arranged so as to overlap with the first boundary BL and the second boundary BS when viewed in a direction perpendicular to the rotation axis of the developing roller 17 (radial direction). As a result, the vicinity of the first boundary BL and the second boundary BS in the end seal 30 includes a region overlapping with the region L in the first portion P1 and a region overlapping with the region L in the second portion P2 when viewed in a direction perpendicular to the rotation axis of the developing roller 17. The first portion P1, the second portion P2, the first boundary BL, and the second boundary BS in the fourth embodiment are similar to those in the first embodiment (see FIG. 2).

[0086] By providing the region L, the contact pressure of the end seal 30 against the developing roller 17 in the region near the first boundary BL and the second boundary BS (near the boundary) becomes higher than the contact pressure in the region outside the vicinity of the boundary.

[0087] The vicinity of the boundary where the contact pressure in the end seal 30 of this embodiment is increased may include an area in the first portion P1 that overlaps with area L and an area in the second portion P2 that overlaps with area L when viewed in a direction perpendicular to the rotational axis of the developing roller 17.

[0088] Specifically, in this embodiment, the thickness (diameter) of the pile yarn in the region other than the region L is about 20 μm, whereas the thickness of the pile yarn in the region L is about 40 μm in diameter.

[0089] Moreover, the formation range of the region L, the arrangement in the longitudinal direction, and the arrangement in the lateral direction may be similar to those of the protrusion 32 in the first embodiment.

[0090] The above dimensions are merely an example and should be appropriately set depending on the device configuration, and are not limited to the above values.

[0091] Even without increasing the number of piles, by increasing the thickness of each pile, it is possible to make the apparent rigidity of region L equivalent to that of a structure with a greater number of piles.

[0092] As a result, similarly to the third embodiment, the contact pressure of the end seal 30 against the developing roller 17 can be relatively increased in the vicinity of the overlapping step J, and the gap occurring at the overlapping step J can be narrowed compared to the conventional configuration without the region L. Therefore, the leakage of toner through the gap occurring at the overlapping step J can be suppressed.

[0093] The method of varying the contact pressure of the pile yarn layer against the developing roller 17 or the developing blade 21 is not limited to the methods of Examples 3 and 4. For example, the length of the pile yarn in the region L may be made longer than the length of the pile yarn in the region excluding the region L, thereby relatively increasing the contact pressure in the region L.

[0094] <Example 5> An image forming apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. 9. The image forming apparatus according to this embodiment has the same configuration as the image forming apparatus according to the first to fourth embodiments. For the image forming apparatus having this configuration, toner T shown in FIG. 9 is used.

[0095] Fig. 9(a) is a schematic diagram of a toner T1 particle used in this embodiment, Fig. 9(b) is a schematic diagram of the section H2 shown in Fig. 9(a) as viewed from the cross-sectional direction, and Fig. 9(c) is a schematic diagram showing two toner particles T meshing with each other at their surfaces.

[0096] 9(b), the toner T has a structure in which a plurality of toner protrusions T2 are dispersed on the surface of the toner matrix T1. The toner protrusions T2 are formed of a material containing an organosilicon polymer, and have a height of 40 to 300 nm from the surface of the toner matrix T1.

[0097] This toner T has the following characteristics due to the effect of the toner protrusions T2 dispersed on the surface. When an aggregate of toner T is exposed to a compressed state where pressure is applied from the outside, the distance between the toner particles T narrows, causing the toner protrusions T2 to interlock more closely. In this interlocking state, the toner T becomes less likely to roll and the force acting in the shear direction between the toner particles T increases, reducing the fluidity of the toner and making it less likely for the toner to leak.

[0098] In the configurations of Examples 1 to 4, the contact pressure between the end seal 30 and the developing roller 17 at the overlapping step J is relatively high, so that when the toner T enters the gap generated at the overlapping step J, the toner protrusions T2 of the toner T tend to mesh with each other. This reduces the fluidity of the toner, making it difficult for the toner to leak.

[0099] As described above, according to this embodiment, since the toner is less likely to flow through the gap generated in the overlapping step J than in the first to fourth embodiments, it is possible to more effectively prevent the toner from leaking.

[0100] Here, the toner used in this embodiment will be described in detail with reference to Fig. 10 and Fig. 11(a) to Fig. 11(c). The toner used in this embodiment includes toner particles having a toner base particle and an organosilicon polymer on the surface of the toner base particle. The organosilicon polymer has a structure represented by the following formula (1). R-SiO 3 / 2 (1) In the formula, R is an alkyl group having 1 to 6 carbon atoms or a phenyl group. The organosilicon polymer forms protrusions on the surface of the toner particles. In the structure represented by formula (1), R is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Preferred examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, and a propyl group. More preferably, R is a methyl group.

[0101] The convex parts of the organosilicon polymer are in surface contact with the surface of the toner base particle. This surface contact is expected to have a significant effect in suppressing the movement, detachment, and embedding of the convex parts when stress is applied to the convex parts. Specifically, even after going through the electrophotographic process of development, transfer, and fixing, the convex parts remain on the fixed image, which reduces the contact area between the image part and the paper discharge member when the paper is discharged, and suppresses the transfer of toner to the paper discharge member.

[0102] In order to show the degree of surface contact between the toner base particle surface and the protrusions, a cross section of the toner is observed by STEM. Schematic diagrams of the protrusions on the toner particle surface are shown in Figure 9 and Figures 11(a) to 11(c). In Fig. 10, 101 is a STEM image, in which about 1 / 4 of the toner particle can be seen, 102 is a toner base particle, 103 is the surface of the toner base particle, and 104 is a convex portion. In Figs. 11(a) to 11(c), 105 is a convex width w, 106 is a convex diameter D, and 10 7 is the convex height H.

[0103] A cross-sectional image of a toner particle is observed, and the contour line of the toner base particle is expanded into a straight line to obtain an expanded image of the cross-sectional image. In the expanded image, the length of the straight line is defined as L. The length of the line segment on the straight line that constitutes the boundary between the convex portion and the toner base particle is defined as the convex width w. In addition, the maximum length of the convex portion in the normal direction of the convex width w is defined as the convex diameter D, and the length from the apex of the convex portion to the straight line on the line segment that forms the convex diameter D is defined as the convex height H.

[0104] 11(a) and 11(c), the convex diameter D and the convex height H are the same, while in FIG. 11(b), the convex diameter D is greater than the convex height H. Also, Figure 11(c) is a schematic representation of the adhesion state of bowl-shaped particles, which are semi-spherical particles with a concave center, obtained by crushing or breaking hollow particles. In Figure 11(c), the convex width w is the total length of the organosilicon polymer in contact with the toner base particle surface. In other words, the convex width w in Figure 11(c) is the total of W1 and W2.

[0105] When the convex height H is 40 nm or more, the convex parts that remain without moving, detaching, or sinking until after fixing will protrude sufficiently to reduce the contact area between the paper discharge member and the image. On the other hand, when the convex height H is greater than 300 nm, the convex parts will move, detach, or sink, especially detach, in response to external stress. Furthermore, the detached convex parts may cause contamination of materials other than the paper discharge member.

[0106] The organosilicon polymer is preferably a condensation polymer of an organosilicon compound having a structure represented by the following formula (Z).

[0107] [ka]

[0108] (In formula (Z), R1 represents a hydrocarbon group having 1 to 6 carbon atoms (preferably an alkyl group), and R2, R3, and R4 each independently represent a halogen atom, a hydroxyl group, an acetoxy group, or an alkoxy group.) R1 is preferably an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and is preferably a methyl group. It is more preferable that

[0109] R2, R3, and R4 are each independently a halogen atom, a hydroxyl group, an acetoxy group, or an alkoxy group (hereinafter also referred to as a reactive group). These reactive groups undergo hydrolysis, addition polymerization, and condensation polymerization to form a crosslinked structure. From the viewpoint of mild hydrolysis at room temperature and deposition onto the surface of the toner base particles, an alkoxy group having 1 to 3 carbon atoms is preferable, and a methoxy group or an ethoxy group is more preferable. In addition, the hydrolysis, addition polymerization, and condensation polymerization of R2, R3, and R4 can be controlled by the reaction temperature, reaction time, reaction solvent, and pH. To obtain an organosilicon polymer, it is advisable to use one or more combinations of organosilicon compounds (hereinafter also referred to as trifunctional silanes) having three reactive groups (R2, R3, and R4) in one molecule excluding R1 in the above formula (Z).

[0110] Examples of the compound represented by the above formula (Z) include the following. Trifunctional methylsilanes such as methyltrimethoxysilane, methyltriethoxysilane, methyldiethoxymethoxysilane, methylethoxydimethoxysilane, methyltrichlorosilane, methylmethoxydichlorosilane, methylethoxydichlorosilane, methyldimethoxychlorosilane, methylmethoxyethoxychlorosilane, methyldiethoxychlorosilane, methyltriacetoxysilane, methyldiacetoxymethoxysilane, methyldiacetoxyethoxysilane, methylacetoxydimethoxysilane, methylacetoxymethoxyethoxysilane, methylacetoxydiethoxysilane, methyltrihydroxysilane, methylmethoxydihydroxysilane, methylethoxydihydroxysilane, methyldimethoxyhydroxysilane, methylethoxymethoxyhydroxysilane, and methyldiethoxyhydroxysilane. Trifunctional silanes such as ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrichlorosilane, ethyltriacetoxysilane, ethyltrihydroxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltrichlorosilane, propyltriacetoxysilane, propyltrihydroxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltrichlorosilane, butyltriacetoxysilane, butyltrihydroxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, hexyltrichlorosilane, hexyltriacetoxysilane, and hexyltrihydroxysilane. Trifunctional phenylsilanes such as phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane, phenyltriacetoxysilane, and phenyltrihydroxysilane.

[0111] In addition, to the extent that the effect of the present invention is not impaired, an organosilicon polymer obtained by combining the following with an organosilicon compound having a structure represented by formula (Z) may be used. An organosilicon compound having four reactive groups in one molecule (tetrafunctional silane), an organosilicon compound having two reactive groups in one molecule (bifunctional silane), or an organosilicon compound having one reactive group (monofunctional silane). For example, the following may be mentioned. Trifunctional vinyl silanes such as dimethyldiethoxysilane, tetraethoxysilane, hexamethyldisilazane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, vinyltriisocyanatesilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyldiethoxymethoxysilane, vinylethoxydimethoxysilane, vinylethoxydihydroxysilane, vinyldimethoxyhydroxysilane, vinylethoxymethoxyhydroxysilane, and vinyldiethoxyhydroxysilane.

[0112] A preferred method for forming the above-mentioned convex shape on the toner particle surface includes, for example, a method in which toner base particles are dispersed in an aqueous medium to obtain a toner base particle dispersion, and an organosilicon compound is added to the toner base particle dispersion to form a convex shape, thereby obtaining a toner particle dispersion.

[0113] The toner base particle dispersion liquid is preferably adjusted to have a solids concentration of 25% by mass or more and 50% by mass or less. The temperature of the toner base particle dispersion liquid is preferably adjusted to 35° C. or more. The pH of the toner base particle dispersion liquid is preferably adjusted to a pH at which condensation of the organosilicon compound does not proceed easily. The pH at which condensation of the organosilicon polymer does not proceed easily varies depending on the substance, so it is preferably within ±0.5 of the pH at which the reaction does not proceed easily.

[0114] On the other hand, it is preferable to use an organosilicon compound that has been subjected to hydrolysis treatment. For example, the organosilicon compound is hydrolyzed in a separate vessel as a pretreatment. The concentration of water from which ions have been removed, such as ion-exchanged water or RO water, is preferably 40 parts by mass to 500 parts by mass, and more preferably 100 parts by mass to 400 parts by mass, based on 100 parts by mass of the organosilicon compound. The following is more preferred: The hydrolysis conditions are preferably a pH of 2 to 7, a temperature of 15 to 80° C., and a time of 30 to 600 minutes.

[0115] The obtained hydrolysis liquid is mixed with the toner base particle dispersion liquid, and the pH is adjusted to a value suitable for condensation (preferably 6 to 12, or 1 to 3, more preferably 8 to 12). The amount of the hydrolysis liquid is adjusted to 5.0 parts by mass or more and 30.0 parts by mass or less of the organosilicon compound per 100 parts by mass of the toner base particles, which makes it easier to form the convex shape. The temperature and time for the formation of the convex shape and the condensation are preferably maintained at 35°C to 99°C for 60 minutes to 72 hours.

[0116] In addition, in controlling the convex shape of the surface of the toner particles, it is preferable to adjust the pH in two stages. The convex shape of the surface of the toner particles can be controlled by appropriately adjusting the holding time before adjusting the pH and the holding time before adjusting the pH in the second stage to condense the organosilicon compound. For example, it is preferable to hold at pH 4.0 to 6.0 for 0.5 to 1.5 hours, and then at pH 8.0 to 11.0 for 3.0 to 5.0 hours. The convex shape can also be controlled by adjusting the condensation temperature of the organosilicon compound in the range of 35°C to 80°C. For example, the convex width w can be controlled by the amount of organosilicon compound added, the reaction temperature, the first-stage reaction pH, the reaction time, etc. For example, the convex width tends to increase as the first-stage reaction time increases. The convex diameter D and convex height H can be controlled by the hydrolysis temperature of the organosilicon compound, the amount of organosilicon polymer added, the reaction temperature, the pH of the second stage, etc. For example, a high hydrolysis temperature tends to increase the convex height H. Also, a high second stage reaction pH tends to increase the convex diameter D and convex height H.

[0117] Specific methods for producing the toner will be described below, but the methods are not limited thereto. It is preferred that the toner base particles are produced in an aqueous medium, and that protrusions containing an organosilicon polymer are formed on the surface of the toner base particles. The preferred methods for producing toner base particles are suspension polymerization, solution suspension, and emulsion aggregation, with suspension polymerization being more preferred. In suspension polymerization, organosilicon polymers tend to precipitate uniformly on the surface of toner base particles, making it easier to reduce the contact area between the protrusions on the fixed image and the paper discharge member. The suspension polymerization will be described in more detail below.

[0118] The suspension polymerization method is a method in which a polymerizable monomer composition containing a polymerizable monomer capable of producing a binder resin and, if necessary, an additive such as a colorant is granulated in an aqueous medium, and the polymerizable monomer contained in the polymerizable monomer composition is polymerized to obtain toner base particles. The polymerizable monomer composition may contain a release agent or other resins as necessary. After the polymerization step is completed, the generated particles may be washed, collected by filtration, and dried by a known method. The temperature may be raised in the latter half of the polymerization step. In addition, in order to remove unreacted polymerizable monomers or by-products, it is also possible to distill off a part of the dispersion medium from the reaction system in the latter half of the polymerization step or after the polymerization step is completed. It is preferable to use the thus obtained toner base particles to form convex portions of the organosilicon polymer by the above-mentioned method.

[0119] The toner may contain a release agent. Examples of the release agent include the following. petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum and their derivatives, montan wax and its derivatives, hydrocarbon waxes produced by the Fischer-Tropsch process and their derivatives, polyolefin waxes such as polyethylene and polypropylene and their derivatives, natural waxes such as carnauba wax and candelilla wax and their derivatives, higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid, or their acid amides, esters, or ketones, hydrogenated castor oil and its derivatives, Vegetable wax, animal wax, silicone resin. The derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. The release agents may be used alone or in combination. The content of the release agent is preferably 2.0 parts by mass or more and 30.0 parts by mass or less with respect to 100 parts by mass of the binder resin or the polymerizable monomer that produces the binder resin.

[0120] As the other resin, for example, the following resins can be used. Homopolymers of styrene and its substituted derivatives, such as polystyrene and polyvinyltoluene; styrene-based copolymers, such as styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene-octyl acrylate copolymers, styrene-dimethylaminoethyl acrylate copolymers, styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, styrene-butyl methacrylate copolymers, styrene-dimethylaminoethyl methacrylate copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resins, polyester resins, polyamide resins, epoxy resins, polyacrylic resins, rosin, modified rosin, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, and aromatic petroleum resins. These may be used alone or in combination.

[0121] Suitable examples of the polymerizable monomer include the vinyl polymerizable monomers shown below. Styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate acrylic polymerizable monomers such as ethyl acrylate and 2-benzoyloxyethyl acrylate; methacrylic polymerizable monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate, and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, and vinyl formate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone. Among these vinyl monomers, styrene, styrene derivatives, acrylic polymerizable monomers and methacrylic polymerizable monomers are preferred.

[0122] In addition, a polymerization initiator may be added when polymerizing the polymerizable monomer. Examples include the following: azo- or diazo-based polymerization initiators such as 2,2'-azobis-(2,4-divaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile; peroxide-based polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyloxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide. These polymerization initiators are preferably added in an amount of 0.5 to 30.0 parts by mass per 100 parts by mass of the polymerizable monomer, and may be used alone or in combination of two or more.

[0123] In order to control the molecular weight of the binder resin constituting the toner base particles, a chain transfer agent may be added during polymerization of the polymerizable monomer. The preferred amount of the chain transfer agent is 0.001 to 15,000 parts by mass per 100 parts by mass of the polymerizable monomer.

[0124] On the other hand, in order to control the molecular weight of the binder resin constituting the toner base particles, a crosslinking agent may be added during polymerization of the polymerizable monomer. For example, the following may be mentioned. Divinylbenzene, bis(4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #200, #400, #600 diacrylates, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester diacrylate (MANDA Nippon Kayaku), and those in which the above acrylates have been replaced with methacrylates. Examples of polyfunctional crosslinking monomers include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis(4-methacryloxy-polyethoxyphenyl)propane, diacryl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, and diaryl chlorendate. The preferred amount added is 0.001 to 15,000 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

[0125] When the medium used in the suspension polymerization is an aqueous medium, the following can be used as a dispersion stabilizer for the particles of the polymerizable monomer composition. Tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina. Examples of organic dispersants include polyvinyl alcohol, gelatin, methyl cellulose, methylhydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, and starch. Commercially available nonionic, anionic, or cationic surfactants may also be used. Examples of such surfactants include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, and potassium stearate.

[0126] A colorant may be used in the toner, and there is no particular limitation, and any known colorant may be used. . The content of the colorant is preferably 3.0 parts by mass to 15.0 parts by mass with respect to 100 parts by mass of the binder resin or polymerizable monomer.

[0127] A charge control agent can be used during toner production, and known charge control agents can be used. The amount of these charge control agents added is preferably 0.01 to 10.00 parts by mass with respect to 100 parts by mass of the binder resin or polymerizable monomer.

[0128] The toner particles may be used as they are as a toner, or various organic or inorganic fine powders may be added to the toner particles as necessary. From the viewpoint of durability when added to the toner particles, the organic or inorganic fine powder preferably has a particle size of 1 / 10 or less of the weight average particle size of the toner particles. As the organic or inorganic fine powder, for example, the following can be used. (1) Fluidity imparting agents: silica, alumina, titanium oxide, carbon black and carbon fluoride. (2) Abrasives: metal oxides (e.g., strontium titanate, cerium oxide, alumina, magnesium oxide, chromium oxide), nitrides (e.g., silicon nitride), carbides (e.g., silicon carbide), metal salts (e.g., calcium sulfate, barium sulfate, calcium carbonate). (3) Lubricants: Fluorine-based resin powder (e.g., vinylidene fluoride, polytetrafluoroethylene), fatty acid metal salts (e.g., zinc stearate, calcium stearate). (4) Charge control particles: metal oxides (e.g., tin oxide, titanium oxide, zinc oxide, silica, alumina), carbon black.

[0129] In order to improve the fluidity of the toner and to make the toner uniformly charged, the organic or inorganic fine powder may be subjected to a surface treatment. Examples of the treatment agent for the hydrophobic treatment of the organic or inorganic fine powder include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, and organic titanium compounds. These treatment agents may be used alone or in combination.

[0130] The methods for measuring various physical properties are described below. <Method of observing the cross section of a toner using a scanning transmission electron microscope (STEM)> A cross section of a toner to be observed with a scanning transmission electron microscope (STEM) is prepared as follows. The procedure for preparing the cross section of the toner will be described below. First, the toner is spread onto a cover glass (Matsunami Glass Co., Ltd., square cover glass; square No. 1) to form a single layer, and then an osmium plasma coater (Filgen Co., Ltd., OPC80T) is used to apply an Os film (5 nm) and a naphthalene film (20 nm) to the toner as a protective film. Next, a PTFE tube (inner diameter Φ1.5 mm × outer diameter Φ3 mm × 3 mm) is filled with photocurable resin D800 (JEOL Ltd.), and the cover glass is gently placed on top of the tube so that the toner is in contact with the photocurable resin D800. In this state, the resin is hardened by irradiating it with light, and then the cover glass and tube are removed to form a cylindrical resin with the toner embedded in the outermost surface. Using an ultrasonic ultramicrotome (Leica, UC7), a cutting speed of 0.6 mm / s is used to cut from the outermost surface of the cylindrical resin to the length of the toner radius (for example, 4.0 μm when the weight average particle size (D4) is 8.0 μm) to expose a cross section of the center of the toner. Next, a thin sample of the cross section of the toner is prepared by cutting it to a thickness of 100 nm. By cutting in this manner, a cross section of the center of the toner can be obtained. The probe size of the STEM is 1 nm, and the image size is 1024 x 1024 pixels. Adjust st to 1425, Brightness to 3750, and in the ImageControl panel, set Contrast to 0.0, Brightness to 0.5, and Gamma to 1.00, and capture an image. The image magnification is 100,000 times, and the image is captured so that it covers about one-quarter to one-half of the circumference of the cross section of one toner particle, as shown in Figure 9.

[0131] The obtained images are analyzed using image processing software (Image J (available from https: / / imagej.nih.gov / ij / )) and the convex parts containing the organosilicon polymer are measured. Image analysis is performed on 30 STEM images. First, use the line drawing tool (select Segmented line in the Straight tab) to draw a line along the periphery of the toner base particle. In areas where the protruding parts of the organosilicon polymer are embedded in the toner base particle, connect the lines smoothly, treating the embedded area as if it were not there, so as to maintain the curvature of the periphery of the toner base particle. Convert the line into a straight line (select Selection on the Edit tab, change the line width to 500 pixels in the properties, then select Selection on the Edit tab and run Straightener). This gives an expanded image in which the contours of the toner base particles are expanded into straight lines. In the expanded image, the convex width w, convex diameter D and convex height H are measured for each convex portion containing the organosilicon polymer. In the developed image, the length of the straight line is defined as L. L corresponds to the length of the toner base particle surface in the STEM image. The length of the line segment on the straight line that constitutes the boundary between the convex portion and the toner base particle is defined as the convex width w. In addition, the maximum length of the convex portion in the normal direction of the convex width w is defined as the convex diameter D, and the length from the apex of the convex portion (the outer apex of the toner particle) on the line segment that forms the convex diameter D to the straight line is defined as the convex height H.

[0132] The sum of the convex widths w of the "specific height convex parts" that exist in the developed images used for image analysis and have a convex height H of 40 nm to 300 nm is defined as Σw. Σw / L is calculated from one image, and the arithmetic mean value of 30 STEM images is used. In addition, P(D / w) is calculated from the results of measuring 30 STEM images. The cumulative distribution of the convex height H is taken to calculate H80. Detailed measurement of the convex portion is as described above and shown in Figs. 11(a) to 11(c). Measurements are performed in Image J by overlaying the scale on the image with Straight Line on the Straight tab, and setting the length of the scale on the image with Set Scale on the Analyze tab. A line segment equivalent to the convex width w or convex height H can be drawn with Straight Line on the Straight tab, and measurements can be performed with Measure on the Analyze tab.

[0133] The above embodiments can be combined with each other as far as possible.

[0134] The disclosure of the embodiments of the present invention includes the following configurations. (Configuration 1) A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner and an opening for opening the container; a roller rotatably supported by the frame in the opening; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between the frame and a surface of the blade opposite to a surface that contacts the roller, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: The frame has a seating surface for the seal member and a protrusion protruding from the seating surface, The developing device, wherein the protrusion is disposed so as to be in contact with a boundary between the first portion and the second portion of the seal member. (Configuration 2) The developing device described in configuration 1, characterized in that the vicinity of the boundary in the sealing member includes an area in the first portion that is compressed between the protrusion and the opposite surface of the blade, and an area in the second portion that is compressed between the protrusion and the roller. (Configuration 3) 3. The developing device according to configuration 2, wherein the sealing member is compressed so that a thickness at a portion in contact with the protrusion is smaller than a thickness at a portion not in contact with the protrusion. (Configuration 4) A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between the frame and a surface of the blade opposite to a surface that contacts the roller, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: the sealing member has an elastic layer on a side in contact with the frame; The elastic layer includes a first elastic portion having a first hardness and a second elastic portion having a second hardness higher than the first hardness, A developing device characterized in that the second elastic portion is arranged so as to overlap the boundary between the first portion and the second portion of the sealing member when viewed in a direction perpendicular to the rotational axis of the roller. (Configuration 5) The developing device described in configuration 4, characterized in that the vicinity of the boundary in the sealing member includes, when viewed in the perpendicular direction, an area that overlaps with the second elastic portion in the first portion and an area that overlaps with the second elastic portion in the second portion. (Configuration 6) A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between the frame and a surface of the blade opposite to a surface that contacts the roller, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: the sealing member has a pile yarn layer on a side in contact with the roller and the blade, the pile yarn layer includes a first pile yarn layer that contacts the roller and the blade with a first contact pressure, and a second pile yarn layer that contacts the roller and the blade with a second contact pressure higher than the first contact pressure, A developing device characterized in that the second pile yarn layer is arranged so as to overlap the boundary between the first and second portions of the sealing member when viewed in a direction perpendicular to the rotational axis of the roller. (Configuration 7) The vicinity of the boundary in the sealing member is, when viewed in the perpendicular direction, 7. The developing device according to claim 6, further comprising: a region overlapping with the second pile yarn layer in the first portion; and a region overlapping with the second pile yarn layer in the second portion. (Configuration 8) the first pile yarn layer is a first density portion having a first number of pile yarns per unit area; 8. The developing device according to configuration 7, wherein the second pile yarn layer is a second density portion having a second number of pile yarns per unit area that is greater than the first number. (Configuration 9) The first pile yarn layer is a first pile yarn portion in which pile yarns of a first thickness are arranged, The developing device according to configuration 7, wherein the second pile thread layer is a second pile thread portion in which pile threads having a second thickness that is thicker than the first thickness are arranged. (Configuration 10) the boundary includes a first boundary extending along a rotational axis of the roller and a second boundary extending along a circumferential direction around the rotational axis, The developing device according to any one of configurations 1 to 9, wherein the vicinity of the boundary includes at least the first boundary. (Configuration 11) The developing device according to any one of configurations 1 to 10, characterized in that the vicinity of the boundary includes an area in the second portion that faces the tip surface of the blade, and an area in the first portion that sandwiches the tip of the blade between the roller. (Configuration 12) the toner contained in the container includes toner particles having toner base particles and an organosilicon polymer on the surface of the toner base particles, The organosilicon polymer has a structure represented by the following formula (1): 12. The developing device according to any one of Configurations 1 to 11, wherein the organosilicon polymer forms convex portions on the surfaces of the toner base particles. R-SiO 3 / 2 (1) (In formula (1), R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group.) (Configuration 13) 13. The developing device according to any one of configurations 1 to 12, which is detachably mountable to the main body of the image forming apparatus. (Configuration 14) A process cartridge detachably mountable to a main body of an image forming apparatus, a photoreceptor on which an electrostatic image is formed; A developing device according to any one of configurations 1 to 13 for developing an electrostatic image formed on the photoconductor; A process cartridge comprising: (Configuration 15) An image forming apparatus for forming an image on a recording material, 14. An image forming apparatus comprising the developing device according to any one of the first to third aspects. (Configuration 16) An image forming apparatus for forming an image on a recording material, 15. An image forming apparatus comprising the process cartridge according to aspect 14. [Explanation of symbols]

[0135] 4...developing unit, 17...developing roller, 18...developing frame, 18b...developing chamber, 18c...opening, 21...developing blade, 30...end seal, 31...end seal seat, 32...projection

Claims

1. A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between a surface of the blade opposite to a surface that contacts the roller and the frame, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: The frame has a seating surface for the seal member and a protrusion protruding from the seating surface, The developing device, wherein the protrusion is disposed so as to be in contact with a boundary between the first portion and the second portion of the seal member.

2. 2. The developing device according to claim 1, wherein the vicinity of the boundary in the sealing member includes an area in the first portion that is compressed between the protrusion and the opposite surface of the blade, and an area in the second portion that is compressed between the protrusion and the roller.

3. 3. The developing device according to claim 2, wherein the seal member is compressed so that a thickness at a portion in contact with the protrusion is smaller than a thickness at a portion not in contact with the protrusion.

4. A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; a seal member having a first portion compressed between a surface of the blade opposite to a surface that contacts the roller and the frame, and a second portion connected to the first portion and compressed between the roller and the frame; In a developing device comprising: the sealing member has an elastic layer on a side in contact with the frame; The elastic layer includes a first elastic portion having a first hardness and a second elastic portion having a second hardness higher than the first hardness, A developing device characterized in that the second elastic portion is arranged so as to overlap the boundary between the first portion and the second portion of the sealing member when viewed in a direction perpendicular to the rotational axis of the roller.

5. The developing device according to claim 4, characterized in that the vicinity of the boundary in the sealing member includes, when viewed in the perpendicular direction, an area in the first portion that overlaps with the second elastic portion and an area in the second portion that overlaps with the second elastic portion.

6. A developing device provided in an image forming apparatus that forms an image on a recording material, a frame having a container for containing toner; a roller rotatably supported by the frame at an opening that opens the storage section; a blade that contacts the roller so as to regulate the thickness of a layer of toner carried on the roller; The blade is compressed between a surface opposite to a surface that contacts the roller and the frame. a seal member having a first portion that is compressed between the roller and the frame and a second portion that is connected to the first portion and is compressed between the roller and the frame; In a developing device comprising: the sealing member has a pile yarn layer on a side in contact with the roller and the blade, the pile yarn layer includes a first pile yarn layer that contacts the roller and the blade with a first contact pressure, and a second pile yarn layer that contacts the roller and the blade with a second contact pressure higher than the first contact pressure, A developing device characterized in that the second pile thread layer is arranged so as to overlap the boundary between the first portion and the second portion of the sealing member when viewed in a direction perpendicular to the rotational axis of the roller.

7. The developing device according to claim 6, characterized in that the vicinity of the boundary in the sealing member includes, when viewed in the perpendicular direction, an area in the first portion that overlaps with the second pile yarn layer and an area in the second portion that overlaps with the second pile yarn layer.

8. the first pile yarn layer is a first density portion having a first number of pile yarns per unit area; 8. The developing device according to claim 7, wherein the second pile layer is a second density portion having a second number of pile yarns per unit area which is greater than the first number.

9. The first pile yarn layer is a first pile yarn portion in which pile yarns of a first thickness are arranged, 8. The developing device according to claim 7, wherein the second pile thread layer is a second pile thread portion in which pile threads having a second thickness that is thicker than the first thickness are arranged.

10. the boundary includes a first boundary extending along a rotational axis of the roller and a second boundary extending along a circumferential direction around the rotational axis, The developing device according to claim 1 , wherein the vicinity of the boundary includes at least the first boundary.

11. 2. The developing device according to claim 1, wherein the vicinity of the boundary includes an area facing the tip surface of the blade in the second portion, and an area sandwiching the tip of the blade between the roller and the first portion.

12. the toner contained in the container includes toner particles having toner base particles and an organosilicon polymer on the surface of the toner base particles, The organosilicon polymer has a structure represented by the following formula (1):

12. The developing device according to claim 1, wherein the organosilicon polymer forms convex portions on the surfaces of the toner base particles. R-SiO ３／２ (1) (In formula (1), R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group.)

13. 2. The developing device according to claim 1, which is detachably mountable to a main body of an image forming apparatus.

14. A process cartridge detachably mountable to a main body of an image forming apparatus, a photoreceptor on which an electrostatic image is formed; a developing device according to claim 1 for developing an electrostatic image formed on the photosensitive member; A process cartridge comprising:

15. An image forming apparatus for forming an image on a recording material, An image forming apparatus comprising the developing device according to claim 1.

16. An image forming apparatus for forming an image on a recording material, An image forming apparatus comprising the process cartridge according to claim 11.

Images