JP2015018087A - Developing roller, developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller that can achieve both position accuracy and fitting strength, and reduce the occurrence of image density unevenness caused by the shake of a developing roller due to fitting.SOLUTION: A flange coaxially includes a small diameter part having a small diameter and a large diameter part having a diameter larger than that of the small diameter part; a developing sleeve has a large diameter supporting part provided at the opening end; the small diameter part of the flange has a diameter forming a gap G with the large diameter supporting part of the developing sleeve, and applied with coating material to be inserted into the large diameter supporting part of the developing sleeve, where the coating material has, dispersed therein, resin spheres having a larger diameter than the gap and containing an adhesive therein and is crushed and bursted when the flange is inserted into the large diameter supporting part of the developing sleeve to disperse the adhesive inside the gap, and metallic spheres having substantially the same diameter as the gap. The fitting of the large diameter part to the large diameter supporting part and the adhesion of the small diameter part by the adhesive enables the joining of the developing sleeve and the flange.

Description

  The present invention relates to a developing roller, a developing device, a process cartridge, and an image forming apparatus used for a copying machine, a facsimile, a printer, and the like. More specifically, the developer carried on the developing sleeve is conveyed to a developing area where the photosensitive drum and the developing sleeve face each other with a gap, and the electrostatic latent image on the photosensitive drum is developed to form a toner image. The present invention relates to a developing roller and a developing device. The present invention also relates to a process cartridge and an image forming apparatus having such a developing device.

  2. Description of the Related Art Conventionally, developing rollers used in electrophotographic developing devices such as copying machines, facsimiles, and printers are configured as follows. That is, the developing roller is fitted and fixed to a magnet roller having a plurality of magnetic poles formed on the surface thereof, a cylindrical developing sleeve in which the magnet roller is accommodated, and both ends of the developing sleeve in which the magnet roller is accommodated. And a pair of flanges. Such a developing roller is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2011-17901).

  In such a developing roller, the developer adsorbed on the surface of the developing sleeve is conveyed to the developing region by rotating only the developing sleeve on the outer periphery with the shaft of the magnet roller fixed. The developer conveyed to the development area is supplied to the photosensitive drum, and the electrostatic latent image formed on the surface of the photosensitive drum is visualized. Note that the developer remaining on the developing sleeve side without being supplied to the photosensitive drum is peeled off from the developing sleeve when it reaches the developer peeling region by the rotation of the developing sleeve. In Patent Document 1, as a method of fixing the flange to the developing sleeve in manufacturing the developing roller, a method of fixing the flange by fitting the flange on the outer peripheral surface of the flange is shown. .

  However, in the method of Patent Document 1, nonuniformity of the adhesive film thickness occurs due to application unevenness when the adhesive is applied to the outer peripheral surface of the flange and the occurrence of liquid dripping from after application to fitting with the developing sleeve. For this reason, there has been a problem that the flange and the developing sleeve are displaced due to the uneven thickness of the adhesive, the runout accuracy as the developing roller is deteriorated, and the developing roller has uneven image density.

  Therefore, in Patent Document 2 (Japanese Patent Application Laid-Open No. 3-43479), in a bonding method in which a shaft-like mating member is inserted and bonded to a cylindrical fitting member via an adhesive layer, the deflection due to a center position shift is caused. In order to suppress this, the following configuration is provided. In other words, the gap between the cylindrical fitting member and the shaft-like mating member is set in consideration of the size of the gap so that the gap is equal at a plurality of locations on the outer circumference of the shaft-like mating member that are separated from each other. A spherical body is mixed in the adhesive to form an adhesive layer, and in this state, the shaft-like fitted member is inserted into the cylindrical fitting member.

  Moreover, in patent document 3 (Unexamined-Japanese-Patent No. 2009-53310), in the cylindrical member which has a flange member in an open part, the adhesive agent containing the particle | grain of a predetermined particle size is used for fixation of the flange member to an open part. After applying this adhesive to the flange member, the flange member is fitted into the opening of the cylindrical member to be bonded and fixed.

  However, in the thing of patent document 2 and 3, after apply | coating an adhesive agent to one fitting member, when fitting to a to-be-fitted member and fitting both together and fixing by adhesive, After application, the adhesive must be fitted before it hardens, requiring a quick operation.

  In view of the above background, the present invention achieves both the positional accuracy and fitting strength of the developing sleeve and the flange when fitted together, and image density unevenness caused by the shake of the developing roller due to the fitting. An object of the present invention is to provide a developing roller that can reduce the occurrence of the above.

In order to solve the above-described problem, the invention according to claim 1
In a developing roller comprising a cylindrical developing sleeve, and a flange that is inserted into and fixed to the opening end of the developing sleeve,
The flange includes a small-diameter small-diameter portion provided on the front end side inserted into the developing sleeve, a large-diameter portion larger in diameter than the small-diameter portion provided on the rear end side from the small-diameter portion, and the large-diameter portion. A rotating shaft that is provided on the rear end side and that rotates the developing sleeve is provided coaxially;
The developing sleeve is provided with a large-diameter corresponding portion into which the large-diameter portion is fitted when the flange is inserted at an opening end portion thereof.
The small-diameter portion has a diameter that forms a gap G between the small-diameter portion and the large-diameter corresponding portion when the paint is applied before insertion of the flange into the opening end portion of the developing sleeve.
The paint has a larger diameter than the gap G and contains an adhesive inside. The paint is crushed and ruptured when the flange is inserted into the opening end of the developing sleeve, and the adhesive is put into the gap. Resin spheres to be diffused and metal spheres having substantially the same diameter as the gap are dispersed,
The developing sleeve and the flange are coupled by fitting the large diameter portion to the large diameter corresponding portion and bonding the small diameter portion with the adhesive to the large diameter corresponding portion. And

  According to the developing roller of the present invention, when the developing sleeve and the flange are fitted to each other, both the positional accuracy and the fitting strength of the both are achieved, and the occurrence of image density unevenness caused by the shaking of the developing roller due to the fitting is generated. Can be reduced.

1 is a configuration diagram illustrating a configuration example of an image forming apparatus according to the present invention. FIG. 3 is a cross-sectional view illustrating a configuration example of a process cartridge and a developing device according to the present invention. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing a structural example of a developing roller. It is explanatory drawing which shows the structure of the flange in the developing roller which concerns on one Embodiment of this invention. It is explanatory drawing about the evaluation method of a developing roller. It is explanatory drawing explaining the fitting state of the developing sleeve and flange in the developing roller which concerns on one Embodiment of this invention, (a) shows before fitting and (b) shows after fitting. It is explanatory drawing explaining the fitting state of the developing sleeve and flange in the developing roller which concerns on the 2nd Embodiment of this invention, (a) shows before fitting and (b) shows after fitting. It is explanatory drawing explaining the structural example of the flange in the developing roller which concerns on 3rd Example of this invention, (a) is 1st Example, (b) is 2nd Example, (c) is 1st. Example 3 is shown. The performance comparison table | surface of the 1st-5th Example of the developing roller which concerns on this invention is shown. It is a performance comparison table of the 1st-3rd comparative example of a development roller.

(First embodiment)
The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration example of an image forming apparatus according to the present invention. FIG. 2 is a cross-sectional view illustrating a configuration example of a process cartridge and a developing device in the image forming apparatus of FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2 showing a structural example of the developing roller.

  The image forming apparatus 1 prints an image of each color of yellow (Y), magenta (M), cyan (C), and black (K), that is, a color image, on a recording sheet 7 (shown in FIG. 1). ) To form. The units corresponding to the colors of yellow, magenta, cyan, and black are indicated by adding Y, M, C, and K at the end of the reference numerals. As shown in FIG. 1, the image forming apparatus 1 includes an apparatus main body 2, a paper feeding unit 3, a transfer unit 4, a fixing unit 5, a registration roller pair 10, and a plurality of laser writing units 22Y, 22M, and 22C. , 22K. The image forming apparatus 1 further includes a plurality of process cartridges 6Y, 6M, 6C, and 6K.

  The apparatus main body 2 is formed in a box shape, for example, and is installed on a floor or the like. The apparatus main body 2 includes a paper feeding unit 3, a transfer unit 4, a fixing unit 5, a plurality of process cartridges 6Y, 6M, 6C, and 6K, a pair of registration rollers 10, and a plurality of laser writing units 22Y, 22M, and 22C. , 22K.

  A plurality of paper feed units 3 are provided in the lower part of the apparatus main body 2. The paper feed unit 3 includes a paper feed cassette 23 that accommodates the above-described recording paper 7 in a stacked manner and can be freely inserted into and removed from the apparatus main body 2, and a paper feed roller 24. The paper feed roller 24 is pressed against the uppermost recording paper 7 in the paper feed cassette 23. The paper feed roller 24 is configured to transfer the above-described uppermost recording paper 7 to a transfer belt 29 (to be described later) of the transfer unit 4, a photosensitive drum 8 of the developing device 13 (to be described later) of the process cartridges 6Y, 6M, 6C, and 6K, Send out in between.

  The registration roller pair 10 is provided in the conveyance path of the recording paper 7 conveyed from the paper supply unit 3 to the transfer unit 4, and includes a pair of rollers 10a and 10b. The registration roller pair 10 sandwiches the recording sheet 7 between the pair of rollers 10a and 10b, and the transfer unit 4 and the process cartridges 6Y, 6M, 6C, and 6K at a timing at which the sandwiched recording sheet 7 can be superimposed on the toner image. And send out between.

  The transfer unit 4 is provided above the paper feed unit 3. The transfer unit 4 includes a drive roller 27, a driven roller 28, a conveyance belt 29, and transfer rollers 30Y, 30M, 30C, and 30K. The driving roller 27 is disposed on the downstream side in the conveyance direction of the recording paper 7 and is rotationally driven by a motor as a driving source. The driven roller 28 is rotatably supported by the apparatus main body 2 and is disposed on the upstream side in the conveyance direction of the recording paper 7. The conveyor belt 29 is formed in an endless annular shape and is stretched over both the driving roller 27 and the driven roller 28 described above. The conveyance belt 29 circulates (endlessly travels) around the driving roller 27 and the driven roller 28 described above in the counterclockwise direction in the drawing as the driving roller 27 is rotationally driven.

  The transfer rollers 30Y, 30M, 30C, and 30K sandwich the conveyance belt 29 and the recording paper 7 on the conveyance belt 29 between the photosensitive drums 8 of the process cartridges 6Y, 6M, 6C, and 6K, respectively. In the transfer unit 4, the transfer rollers 30Y, 30M, 30C, and 30K press the recording paper 7 fed from the paper feed unit 3 against the outer surface of the photosensitive drum 8 of each process cartridge 6Y, 6M, 6C, and 6K. The toner image on the photosensitive drum 8 is transferred to the recording paper 7. The transfer unit 4 sends the recording paper 7 onto which the toner image has been transferred toward the fixing unit 5.

  The fixing unit 5 is provided downstream of the transfer unit 4 in the conveyance direction of the recording paper 7 and includes a pair of rollers 5 a and 5 b that sandwich the recording paper 7 therebetween. The fixing unit 5 presses and heats the recording paper 7 sent out from the transfer unit 4 between the pair of rollers 5a and 5b, whereby the toner image transferred from the photosensitive drum 8 onto the recording paper 7 is recorded on the recording paper 7. Fix to paper 7.

  The laser writing units 22Y, 22M, 22C, and 22K are attached to the upper part of the apparatus main body 2, respectively. The laser writing units 22Y, 22M, 22C, and 22K correspond to one process cartridge 6Y, 6M, 6C, and 6K, respectively. The laser writing units 22Y, 22M, 22C, and 22K irradiate laser beams onto the outer surface of the photosensitive drum 8 that is uniformly charged by a later-described charging roller 9 of the process cartridges 6Y, 6M, 6C, and 6K. An electrostatic latent image is formed.

  The process cartridges 6Y, 6M, 6C, and 6K are provided between the transfer unit 4 and the laser writing units 22Y, 22M, 22C, and 22K, respectively. The process cartridges 6Y, 6M, 6C, and 6K are detachable from the apparatus main body 2. The process cartridges 6Y, 6M, 6C, and 6K are arranged in parallel along the conveyance direction of the recording paper 7.

  As shown in FIG. 2, the process cartridges 6Y, 6M, 6C, and 6K include a cartridge case 11, a charging roller 9 as a charging device, a photosensitive drum (also referred to as an image carrier) 8, and a cleaning device as a cleaning device. A blade 12 and a developing device 13 are provided. Therefore, the image forming apparatus 1 includes at least a charging roller 9, a photosensitive drum 8, a cleaning blade 12, and a developing device 13.

  The cartridge case 11 is detachable from the apparatus main body 2 and accommodates a charging roller 9, a photosensitive drum 8, a cleaning blade 12, and a developing device 13. The charging roller 9 uniformly charges the outer surface of the photosensitive drum 8. The photosensitive drum 8 is disposed with a gap from a later-described developing roller 15 of the developing device 13. The photosensitive drum 8 is formed in a columnar shape or a cylindrical shape that is rotatable about an axis. An electrostatic latent image is formed on the outer surface of the photosensitive drum 8 by the corresponding laser writing units 22Y, 22M, 22C, and 22K. The photosensitive drum 8 is developed by adsorbing toner onto an electrostatic latent image formed on and carried on the outer surface, and the toner image thus obtained is transferred to the recording paper 7 positioned between the conveyance belt 29. To do. The cleaning blade 12 removes the transfer residual toner remaining on the outer surface of the photosensitive drum 8 after transferring the toner image to the recording paper 7.

  As shown in FIG. 2, the developing device 13 includes at least a developer supply unit 14, a developing roller 15 as a developer carrier, a doctor blade 16 as a regulating member, and a case 25. The developer supply unit 14 includes a storage tank 17 and a pair of stirring screws 18 as stirring members. The storage tank 17 is formed in a box shape whose length is substantially equal to that of the photosensitive drum 8. A partition wall 19 extending along the longitudinal direction of the storage tank 17 is provided in the storage tank 17. The partition wall 19 partitions the storage tank 17 into a first space 20 and a second space 21. Further, the first space 20 and the second space 21 communicate with each other at both ends.

  The storage tank 17 stores the developer 26 in both the first space 20 and the second space 21. The developer 26 includes toner and a magnetic carrier (also referred to as magnetic powder). The toner is appropriately supplied to one end of the first space 20 on the side of the first space 20 and the second space 21 that is away from the developing roller 15. The toner is spherical fine particles produced by an emulsion polymerization method or a suspension polymerization method. The toner may be obtained by pulverizing a lump composed of a synthetic resin in which various dyes or pigments are mixed and dispersed. The average particle diameter of the toner is 3 μm or more and 7 μm or less. The toner may be formed by pulverization or the like. The magnetic carrier is accommodated in both the first space 20 and the second space 21. The average particle size of the magnetic carrier is 20 μm or more and 50 μm or less.

  The stirring screw 18 is accommodated in each of the first space 20 and the second space 21. The longitudinal direction of the stirring screw 18 is parallel to the longitudinal directions of the storage tank 17, the developing roller 15, and the photosensitive drum 8. The agitating screw 18 is provided so as to be rotatable around an axis, and rotates around the axis to agitate the toner and the magnetic carrier and convey the developer 26 along the axis. In the illustrated example, the agitation screw 18 in the first space 20 conveys the developer 26 from one end to the other end. The agitating screw 18 in the second space 21 conveys the developer 26 from the other end portion to one end portion.

  According to the above-described configuration, the developer supply unit 14 conveys the toner supplied to one end portion of the first space 20 to the other end portion while stirring with the magnetic carrier, and from the other end portion to the second space. 21 to the other end. Then, the developer supply unit 14 agitates the toner and the magnetic carrier in the second space 21 and supplies them to the outer surface of the developing roller 15 while transporting them in the axial direction.

  The case 25 is formed in a box shape, is attached to the storage tank 17 of the developer supply unit 14 described above, and covers the developing roller 15 and the like together with the storage tank 17. In addition, an opening 25 a is provided in a portion of the case 25 that faces the photosensitive drum 8.

  The developing roller 15 is formed in a columnar shape, and is provided between the second space 21 and the photosensitive drum 8 and in the vicinity of the opening 25a described above. The developing roller 15 is parallel to both the photosensitive drum 8 and the storage tank 17. The developing roller 15 is disposed at a distance from the photosensitive drum 8. The space between the developing roller 15 and the photosensitive drum 8 forms a developing area 31 in which the toner of the developer 26 is attracted to the photosensitive drum 8 and the electrostatic latent image is developed to obtain a toner image. . In the developing area 31, the developing roller 15 and the photosensitive drum 8 face each other.

  As shown in FIGS. 2 and 3, the developing roller 15 includes a cored bar 34, a cylindrical magnet roller (also referred to as a magnet body) 33, the above-described cylindrical developing sleeve 32, and a flange 35. . The core metal 34 is arranged in parallel with the longitudinal direction of the photosensitive drum 8 in the longitudinal direction, and is fixed to the case 25 without rotating. The flange 35 is fixed by a fitting method described later.

  The magnet roller 33 is made of a magnetic material and is formed in a cylindrical shape, and a plurality of fixed magnetic poles (not shown) are attached to the magnet roller 33. The magnet roller 33 is fixed to the outer periphery of the cored bar 34 without rotating around the axis. The fixed magnetic pole is a long bar-like magnet and is attached to the magnet roller 33. The fixed magnetic pole extends along the longitudinal direction of the magnet roller 33, that is, the developing roller 15, and is provided over the entire length of the magnet roller 33. The magnet roller 33 configured as described above is accommodated (enclosed) in the developing sleeve 32.

  One fixed magnetic pole is opposed to the agitating screw 18 described above. The one fixed magnetic pole serves as a pumping magnetic pole. A magnetic force is generated on the outer surface of the developing sleeve 32, that is, the developing roller 15, and the developer 26 in the second space 21 of the storage tank 17 is caused to flow into the developing sleeve 32. Adsorb to the outer surface.

  The other fixed magnetic pole is opposed to the photosensitive drum 8 described above. The fixed magnetic pole forms a developing magnetic pole, and generates a magnetic force on the developing sleeve 32, that is, the outer surface of the developing roller 15, thereby forming a magnetic field between the developing sleeve 32 and the photosensitive drum 8. The fixed magnetic pole forms a magnetic brush by the magnetic field, so that the toner of the developer 26 adsorbed on the outer surface of the developing sleeve 32 is transferred to the photosensitive drum 8.

  At least one fixed magnetic pole is provided between the pumping magnetic pole and the developing magnetic pole. The at least one fixed magnetic pole generates a magnetic force on the outer surface of the developing sleeve 32, that is, the developing roller 15, conveys the developer 26 before development toward the photosensitive drum 8, and develops the developed developer 26. Is conveyed from the photosensitive drum 8 into the storage tank 17.

  When the developer 26 adsorbs the developer 26 to the outer surface of the developing sleeve 32, the fixed magnetic poles described above are stacked on the outer surface of the developing sleeve 32 by superimposing a plurality of magnetic carriers of the developer 26 along the lines of magnetic force generated by the fixed magnetic pole. Stand up (heading). In this way, a state in which a plurality of magnetic carriers are erected on the outer surface of the developing sleeve 32 along the lines of magnetic force is called a magnetic carrier rising on the outer surface of the developing sleeve 32. As a result, the toner described above is adsorbed to the magnetic carrier. That is, the developing sleeve 32 attracts the developer 26 to the outer surface by the magnetic force of the magnet roller 33.

  The developing sleeve 32 is formed in a cylindrical shape. The developing sleeve 32 encloses (accommodates) the magnet roller 33 and is provided to be rotatable around the axis. The developing sleeve 32 is rotated so that the inner peripheral surface thereof is sequentially opposed to the fixed magnetic pole. The developing sleeve 32 is made of a nonmagnetic material such as aluminum alloy, brass, stainless steel (SUS), or conductive resin. The developing sleeve 32 is roughened on the outer surface.

  Aluminum alloys are excellent in terms of workability and lightness. When an aluminum alloy is used, it is preferable to use A6063, A5056, and A3003. When using stainless steel (SUS), it is preferable to use SUS303, SUS304, and SUS316. In the illustrated example, the developing sleeve 32 is made of an aluminum alloy.

  The outer diameter of the developing sleeve 32 is desirably about 14 mm to 30 mm. The length of the developing sleeve 32 in the axis (axial center) direction is preferably about 300 mm to 350 mm.

  The doctor blade 16 is provided at the end of the developing device 13 near the photosensitive drum 8. The doctor blade 16 is attached to the case 25 described above with a space from the outer surface of the developing sleeve 32. The doctor blade 16 scrapes off the developer 26 on the outer surface of the developing sleeve 32 exceeding the desired thickness into the storage tank 17, and the developer on the outer surface of the developing sleeve 32 conveyed to the developing region 31. 26 to the desired thickness.

  In the developing device 13 configured as described above, the developer and the magnetic carrier are sufficiently agitated by the developer supply unit 14, and the agitated developer 26 is adsorbed to the outer surface of the developing sleeve 32 by a fixed magnetic pole. Then, the developing device 13 conveys the developer 26 adsorbed by the plurality of fixed magnetic poles toward the developing region 31 as the developing sleeve 32 rotates. The developing device 13 adsorbs the developer 26 having a desired thickness by the doctor blade 16 to the photosensitive drum 8. In this way, the developing device 13 carries the developer 26 on the developing roller 15 and transports it to the developing area 31 to develop the electrostatic latent image on the photosensitive drum 8 to form a toner image.

  Then, the developing device 13 releases the developed developer 26 toward the storage tank 17. Further, the developed developer 26 stored in the storage tank 17 is again sufficiently agitated with another developer 26 in the second space 21 to develop the electrostatic latent image on the photosensitive drum 8. Used. When the developer supply unit 14 detects that the density of toner supplied to the photosensitive drum 8 has been reduced by a toner density sensor, which will be described later, the developing device 13 rotates the stirring screw 18 to remove the toner from the developing roller. It is designed to pay out toward the 15th.

  The image forming apparatus 1 configured as described above forms an image on the recording paper 7 as described below. First, the image forming apparatus 1 rotates the photosensitive drum 8 and uniformly charges the outer surface of the photosensitive drum 8 to −700 V by the charging roller 9. Laser light is irradiated on the outer surface of the photosensitive drum 8 to expose the photosensitive drum 8, and the image portion is attenuated to −150 V to form an electrostatic latent image on the outer surface of the photosensitive drum 8. . When the electrostatic latent image is positioned in the development area 31, a development bias voltage of −550 V is applied to the electrostatic latent image. As a result, the developer 26 adsorbed on the outer surface of the developing sleeve 32 of the developing device 13 is adsorbed on the outer surface of the photosensitive drum 8 to develop the electrostatic latent image, and the toner image is transferred to the outer surface of the photosensitive drum 8. To form.

  Then, the image forming apparatus 1 positions the conveyed recording sheet 7 between the photosensitive drum 8 of the process cartridges 6Y, 6M, 6C, and 6K and the conveying belt 29 of the transfer unit 4, and the photosensitive drum The toner image formed on the outer surface 8 is transferred to the recording paper 7. The image forming apparatus 1 fixes the toner image on the recording paper 7 by the fixing unit 5. Thus, the image forming apparatus 1 forms a color image on the recording paper 7.

  On the other hand, the toner remaining on the photosensitive drum 8 without being transferred is collected by the cleaning blade 12. The photosensitive drum 8 from which the residual toner has been removed is initialized by a neutralizing lamp (not shown) and used for the next image forming process.

  Further, in the image forming apparatus 1 described above, process control is performed in order to suppress image quality fluctuations due to environmental fluctuations and fluctuations with time. Specifically, first, the developing ability in the developing device 13 is detected. For example, an image of a certain toner pattern is formed on the photosensitive drum 8 under a condition where the developing bias voltage is constant, and the image density is detected by an optical sensor (not shown), and the developing ability is grasped from the density change. Then, the image quality can be kept constant by changing the target value of the toner density so that the developing ability becomes a predetermined target developing ability. For example, when the image density of the toner pattern detected by the optical sensor is lower than the target development density, the CPU as a control means (not shown) drives the motor that rotates the stirring screw 18 so as to increase the toner density. Control the circuit. On the other hand, when the image density of the toner pattern detected by the optical sensor is higher than the target development density, the CPU controls the motor drive circuit described above so as to lower the toner density. Here, the toner density is detected by a toner density sensor (not shown). Note that the image density of the toner pattern formed on the photosensitive drum 8 may slightly vary due to the influence of the image density cycle unevenness caused by the developing sleeve 32 of the developing roller 15.

  In the developing roller 15 described above, a flange 35 is coupled to the opening end of the developing sleeve 32. The flange 35 is used as a reference when the developing sleeve 32 is rotationally driven in the developing device 13. Depending on the relative positional relationship between the flange 35 and the developing sleeve 32, uneven rotation of the developing sleeve 32 occurs when the developing roller 15 rotates. As a result, the image density of the toner pattern formed on the photosensitive drum 8 may cause periodic unevenness due to rotational unevenness of the developing sleeve.

  Therefore, in the present invention, before the flange 35 is inserted into the opening end of the developing sleeve 32, the resin sphere 51 containing the adhesive 55 therein and the sphere 52 having a diameter smaller than the resin sphere are dispersed. Is applied to the flange 35. After applying the coating material 53, the flange 35 is fitted to and coupled to the developing sleeve 32, thereby suppressing the occurrence of a relative position shift between the flange 35 and the developing sleeve 32.

  The flange 35 shown in FIG. 4 is provided with a small-diameter portion 36, a large-diameter portion 37, and a rotating shaft 38 coaxially. The small diameter portion 36 is provided on the leading end side inserted into the developing sleeve 32. A coating 53 for fitting the flange 35 to the developing sleeve 32 and joining it is applied to the outer peripheral surface of the small diameter portion 36. The large diameter portion 37 is provided on the rear end side from the small diameter portion 36. The large-diameter portion 37 has a diameter larger than that of the small-diameter portion 36 so that the large-diameter corresponding portion 32a provided at the opening end portion of the developing sleeve 32 is engaged with the sliding class. The rotating shaft 38 is provided on the rear end side from the large diameter portion 37 and is driven to rotate by a driving source (not shown).

  As shown in FIG. 6A, there is a gap G between the inner diameter of the large diameter corresponding portion 32a of the developing sleeve 32 and the outer peripheral surface of the small diameter portion 36 set to be smaller than the inner diameter. Is formed. In the paint 53 applied to the small diameter portion 36, a resin sphere 51 having a diameter larger than the gap G and including the adhesive 55 therein, and a metal sphere 52 having the same diameter as the gap G are diffused. . The gap G is set to be 3 to 550 μm, and the gap between the outer periphery of the large-diameter portion 37 of the flange 35 and the large-diameter corresponding portion 32a of the developing sleeve 32 is a sliding fitting. As described above, the large diameter of the large diameter portion 37 is set. For example, the outer diameter of the large diameter portion 37 is set to shaft grades h5 to h6. (Example of shaft grade: n6: +15 μm to +28 μm when the shaft dimension is 24 to 30 mm, h5: 0 to −9 μm, h6: 0 to −13 μm).

  As a general method of connecting the flange and the developing sleeve, method 1... "Sliding fitting of shaft + caulking of developing sleeve", method 2 ... "sliding fitting of shaft + adhesive", method 3 ... "shrink fit", method 4 ... "shaft press fitting", etc. The coupling between the flange and the developing sleeve requires not only a relative positional relationship but also a coupling strength. Therefore, each coupling method has advantages and disadvantages with respect to positional accuracy and coupling strength.

  In Method 1, “sliding fitting of shaft + crimping of developing sleeve”, the positional relation accuracy is secured by sliding fitting, and the coupling strength is secured by crimping the developing sleeve. This method is very advantageous in terms of preventing the flange from coming off. However, since the developing sleeve is deformed after inserting the flange, the assembly man-hour is increased, and a large amount of crimping of the developing sleeve is necessary for reliable coupling. There is a case to do.

  In method 2, “shaft fitting and adhesive of shaft”, as in method 1, the accuracy of the positional relationship is ensured by sliding fitting. The bond strength is secured by using an adhesive, and there is no influence such as deformation of the developing sleeve as in Method 1. However, it is difficult to apply the adhesive uniformly, and it is difficult to ensure the same bonding strength throughout the insertion portion. However, since the sticking out of the adhesive still occurs, it is not desirable to use it for the developing roller for transporting the developer.

  In the “shrink fit” of method 3, the bonding strength is ensured by shrink fitting, that is, with the developing sleeve heated and expanded, by inserting a flange and being pinched by the cold developing sleeve. In this method, since the developing sleeve is in an expanded state when the flange is inserted, it is difficult to ensure the positional relationship accuracy.

  In method 4, “shaft press-fitting”, the shaft fitting is made into a press-fit class, so that the positional accuracy is worse than that of the sliding fitting, but the coupling strength is secured more than the sliding fitting. . This bond strength is generally inferior to shrink fitting.

  As described above, there are advantages and disadvantages of securing the positional relationship accuracy and the coupling strength depending on the coupling method. However, in recent years, there has been a desire for both positional accuracy and coupling strength. In Patent Document 1 (Japanese Patent Laid-Open No. 2011-17901), the above-described method 2 “sliding fitting of shaft + adhesive” is developed to achieve both positional accuracy and bonding strength. However, it is good if the adhesive is uniformly coated, but uneven application or dripping during operation may occur. The positional accuracy may vary due to the difference in adhesive film thickness caused by the adhesive film thickness, resulting in the occurrence of uneven image density in the image forming apparatus.

  Therefore, in the present invention, the coating material 53 is applied instead of directly applying the adhesive to the outer peripheral surface of the small diameter portion 36 of the flange 35. In the paint 53, resin spheres 51 having a diameter larger than the gap G and containing the adhesive 55 therein, and metal spheres 52 having the same diameter as the gap G are dispersed. As a result, a developing roller has been invented that solves the problems such as positioning due to coating unevenness and liquid dripping during work, and achieves both the accuracy of the positional relationship between the flange and the developing sleeve and the securing of the coupling strength.

  As described above, the small-diameter portion 36 on the distal end side that is inserted into the developing sleeve 32 of the flange 35 has a gap (gap G) between 3 and 550 μm when the developing sleeve 32 is inserted into the large-diameter corresponding portion 32a. As such, the diameter is set. Further, the outer diameter of the large-diameter portion 37 of the flange 35 is set so that the gap between the outer peripheral surface and the large-diameter corresponding portion 32a of the developing sleeve 32 becomes a sliding-class fitting when the two are fitted. Yes.

  The small diameter portion 36 is coated with a coating 53 in which the outer diameter D1 is set so as to be +2 to +50 μm with respect to the gap G and the resin spheres 51 including the adhesive 55 are dispersed therein. Further, the coating 53 has an outer diameter such that when the flange 35 after application to the small diameter portion 36 is fitted to the developing sleeve 32, the gap with the large diameter corresponding portion 32 a of the developing sleeve 32 becomes −10 to 0 μm. D2 is set, and metal spheres 52 smaller than the resin spheres 51 are also dispersed. If the resin sphere 51 is too large with respect to the gap with the developing sleeve 32, the flange 35 cannot be smoothly inserted, and the position is biased. On the other hand, if the resin sphere 51 is too small, the resin layer does not break. In addition, the bonding strength with the developing sleeve 32 is weakened. If the metal sphere 52 is too large, a positional deviation occurs. If the metal sphere 52 is small, it has no positioning effect. Therefore, the outer diameter of the metal sphere 52 is preferably set as described above.

  The thickness of the external resin of the resin sphere 51 is preferably in the range of 5 to 20 μm. In this range, it is possible to prevent the resin layer from being broken and preventing the adhesive from flowing around. However, this is not the case when the tolerance management of the clearance with the developing sleeve 32 can be precisely managed and the tolerance can be set so that the resin layer can be surely destroyed.

  As shown in FIG. 6B, when the flange 35 having the small-diameter portion 36 coated with the paint 53 is inserted into the large-diameter corresponding portion 32 a of the developing sleeve 32, the resin sphere 51 in the paint 53 is connected to the developing sleeve 32. The adhesive 55 in the resin sphere 51 flows out by being crushed and ruptured by the collision. The flowing out adhesive 55 enters the inner peripheral surface of the large diameter corresponding portion 32 a of the flange 35 on the upper side of the paint 53 and also enters the outer peripheral surface of the small diameter portion 36 of the flange 35 on the lower side of the paint 53. By being cured, the flange 35 and the developing sleeve 32 are joined. At this time, the positional relationship between the developing sleeve 32 and the flange 35 is relatively positioned by the metal sphere 52 and the large-diameter portion 37 of the flange 35, and the connection by joining is completed without changing the positional relationship due to unevenness of the adhesive. Can be made. Therefore, it is possible to achieve both the positional accuracy and the fitting strength of the developing sleeve 32 and the flange 35 when they are fitted, and to reduce the occurrence of image density unevenness caused by the shake of the developing roller due to the fitting. it can. Since the adhesive 55 flows out from the resin sphere 51 when the flange 35 is fitted to the developing sleeve 32, the adhesive 55 does not harden before fitting, so that the fitting work can be performed with a margin. Good sex.

  As for the compounding quantity (Vol%) of the resin sphere 51 and the sphere 52 in the coating material 53, the metal sphere 52: 10-30 (Vol%) is desirable with respect to the resin sphere 51: 30-50 (Vol%). The metal sphere 52 is preferably made of the same material as that of the flange 32. However, even if the material is not necessarily the same, there is no problem in the positioning function.

  The various materials are not limited to these materials as long as the effect can be exhibited, but the material of the metal sphere 52 is aluminum, non-magnetic SUS, etc., and the material of the resin sphere 51 is an adhesive such as urethane resin or polyware resin. A cyanoacrylate-based instant adhesive or the like is used. As the material of the flange 32, aluminum, nonmagnetic SUS, or the like is used. As the material of the paint 53, a synthetic resin mainly made of petroleum is mainly used as a binder as a main component, and examples thereof include an epoxy resin and an acrylic resin. Alcohol or ether is used as the solvent. In addition, in order to make the application state easy to understand, a pigment added further may be used.

  As described above, according to the first embodiment of the present invention, both the positional accuracy and the fitting strength of the developing sleeve and the flange when fitted together are achieved, and the developing roller by fitting is used. Thus, a developing roller can be obtained that can reduce the occurrence of image density unevenness caused by the wobbling. Further, in the fitting and coupling of the developing sleeve and the flange, the fitting work can be performed with a margin and the workability is good. Further, a developing device, a process cartridge, and an image forming apparatus using the developing roller can be obtained.

(Second Embodiment)
FIGS. 7A and 7B are explanatory diagrams for explaining a fitting state of the developing sleeve and the flange in the developing roller according to the second embodiment of the present invention, where FIG. 7A shows before fitting, and FIG. 7B shows after fitting. . In the second embodiment, rib-shaped convex portions 36b are formed in the circumferential direction of the small-diameter portion 36 of the flange 35, and a plurality of (here, two) step portions 36a are formed between the convex portions 36b. All other configurations are the same as those of the first embodiment. The coating material 53 is applied to the stepped portion 36 a on the leading end side that is inserted into the developing sleeve 32.

  As shown in FIG. 7B, after the flange 35 is fitted to the developing sleeve 32, the adhesive 55 that has flowed out due to the resin sphere 51 being crushed and ruptured is applied to the tip of the convex portion 36b between the step portions 36a. Is also adhered and hardened, so that the fitting strength is stronger than in the first embodiment.

(Third embodiment)
FIGS. 8A and 8B are explanatory views for explaining a configuration example of a flange in the developing roller according to the third embodiment of the present invention, in which FIG. 8A is a first example, FIG. 8B is a second example, and FIG. Three examples are shown. The outer peripheral surface of the small diameter portion 36 of the flange 35 to which the coating material 53 including the resin sphere 51 and the metal sphere 52 is applied may have a groove. For example, the grooves are formed in the circumferential direction (see the first example, FIG. 8A), formed in the axial direction (see the third example, FIG. 8C), or formed obliquely in the axial direction. (See the second example, FIG. 8 (b)) or a spiral shape. The coating material 53 is applied to the groove.

  By setting the depth of the groove to 50% to 70% of the diameter of the metal sphere 52, it is possible to minimize the amount of adhesive, and there are few adhesion failures and positional deviations. It is desirable to use it. The inner diameter of the groove portion is set so that the distance from the large diameter corresponding portion 32a when the small diameter portion 35 is inserted into the developing sleeve 32 is the same as the gap G described above. There is no problem if the width of the groove is 130% or more of the diameter of the resin sphere 51. It is desirable that the number of grooves be 40% to 60% with respect to the surface area of the bonding portion 36 because the bonding strength is the strongest, so that the groove is used within this range. However, this does not apply depending on the required strength of the target.

  Further, in the application state of the paint 53 to the groove portion of the small-diameter portion 36 of the flange 35, the resin sphere 51 and the metal sphere 52 are applied in a slightly convex state as compared to the state where the resin sphere 51 and the metal sphere 52 are completely buried in the paint 53. It is desirable to be.

  According to the third embodiment of the present invention, by having such a groove, the contact area of the adhesive 55 flowing out from the resin sphere 51 with the developing sleeve 32 increases, and insufficient adhesion due to the paint 53 is reduced. effective.

  In the image forming apparatus 1 described above, the process cartridges 6Y, 6M, 6C, and 6K include a cartridge case 11, a charging roller 9, a photosensitive drum 8, a cleaning blade 12, and a developing device 13. However, in the present invention, the process cartridges 6Y, 6M, 6C, and 6K only need to include at least the developing device 13, and may not necessarily include the cartridge case 11, the charging roller 9, the photosensitive drum 8, and the cleaning blade 12. good. In the above-described embodiment, the image forming apparatus 1 includes the process cartridges 6Y, 6M, 6C, and 6K that are detachable from the apparatus main body 2. However, in the present invention, the image forming apparatus 1 only needs to include the developing device 13 and may not necessarily include the process cartridges 6Y, 6M, 6C, and 6K.

  Next, an example of a developing roller manufactured according to the present invention and a comparative example not according to the present invention will be described. FIG. 9 shows a performance comparison table of the first to fifth embodiments of the developing roller according to the present invention. FIG. 10 is a performance comparison table of the first to third comparative examples of the developing roller. The image evaluation conditions of the image forming apparatus using the developing roller according to the example and the comparative example are as follows.

Using an image forming apparatus of a commercially available multifunction machine Imagio MP C6001 (manufactured by Ricoh), replacing the developing roller of the example and the comparative example while mounting, using magenta toner, outputting an A4 vertical size full-scale solid image, and image density Unevenness was evaluated. The evaluation criteria are as follows.
◯: The visibility rank of density unevenness is 4 or more. X: The visibility rank of density unevenness is 3 or less (the rank of density unevenness is 1 to 5.5 is the best).

Example 1
In Example 1, the gap G between the developing sleeve 32 and the flange 35 was 10 μm, and the diameter D1 of the resin sphere 51 and the diameter D2 of the metal sphere 52 were D1 = 15 μm and D2 = 8 μm, respectively. Further, the developing roller 15 is made of a coating sleeve 53 made of aluminum having an outer diameter of φ25 mm using a paint 53 in which the blending amount of the resin sphere 51 and the metal sphere 52 is resin sphere 51: metal sphere 52 = 50%: 20%. Formed. The resin sphere 51 contained a cyanoacrylate-based instantaneous adhesive, and the resin layer used urethane resin. The metal sphere 52 was made of aluminum. The inner diameter of the large diameter corresponding portion 32a of the developing sleeve 32 was 23.6 mm, and the outer diameter of the large diameter portion 37 of the flange 35 inserted into the large diameter corresponding portion 32a of the developing sleeve 32 was 23.59 mm. The developing roller 15 has a positioning accuracy of the flange 35 of 3 μm or less and a torque resistance of 4 Nm or more.

  When an image was formed by the image forming apparatus using the developing roller 15 having this configuration, a good image having density unevenness rank 4 and no density unevenness in the circumferential direction was obtained. In addition, in the production under these conditions, both the positioning accuracy and the non-defective rate of torque resistance were 100%. (Positioning accuracy is a shake component of a portion X in FIG. 5. In other words, the shake accuracy of the flange 35 is evaluated with reference to the outer diameter of the developing sleeve 32. In addition, the black triangle in FIG. The surface shown as a reference at the time of measurement is shown. In the case of the developing roller, in order to obtain a uniform image, the shake is required to be 0.003 mm or less.)

(Example 2)
In Example 2, the circumferential groove of the small diameter portion 36 of the flange 35 is provided (FIG. 8A), the gap G with the developing sleeve 32 is 20 μm, the diameter D1 of the resin sphere 51 and the diameter D2 of the metal sphere 52. Were set to D1 = 25 μm and D2 = 15 μm, respectively. In addition, the flange 35 in which a coating 53 in which the blending amount of the resin sphere 51 and the metal sphere 52 is resin sphere 51: metal sphere 52 = 50 vol%: 20 vol% is applied to the circumferential groove of the small diameter portion 36 of the flange 35 is provided. Using. The developing roller 15 in which the developing sleeve 32 is made of aluminum having an outer diameter of φ25 mm was formed. The resin sphere 51 contained a cyanoacrylate-based instantaneous adhesive, and the resin layer used urethane resin. The metal sphere 52 was made of aluminum. The inner diameter of the large diameter corresponding portion 32 of the developing sleeve 32 is 23.6 mm, the outer diameter of the large diameter portion 37 of the flange 35 inserted into the developing sleeve 32 is 23.59 mm, the groove width is 2 mm, and the groove depth is 20 μm. Three grooves are provided. This developing roller has a flange positioning accuracy of 3 μm or less and a torque resistance of 4.5 Nm or more.

  When an image was formed by the image forming apparatus using the developing roller 15 having this configuration, a good image having density unevenness rank 4 and no density unevenness in the circumferential direction was obtained. In addition, in the production under these conditions, the non-defective rate of the positional accuracy and the torque resistance was 100%.

Example 3
In the third embodiment, an axial groove is provided in the small diameter portion 36 of the flange 35 (FIG. 8C), the gap G with the developing sleeve 32 is 10 μm, the diameter D1 of the resin sphere 51 and the diameter D2 of the metal sphere 52. Were set to D1 = 15 μm and D2 = 8 μm, respectively. Further, the flange 35 coated with the paint 53 in which the blending amount of the resin sphere 51 and the metal sphere 52 is set to resin sphere 51: metal sphere 52 = 50%: 10% in the groove on the circumference of the small diameter portion 36 of the flange 35 is provided. Using. Further, the developing roller 15 in which the developing sleeve 32 is made of aluminum having an outer diameter of φ25 mm was formed. The resin sphere 51 contained a cyanoacrylate-based instantaneous adhesive, and the resin layer used urethane resin. The metal sphere 52 was made of aluminum. The inner diameter of the developing sleeve 32 was 23.6 mm, and the outer diameter of the large diameter portion 37 of the flange 35 inserted into the developing sleeve 32 was 23.59 mm. Further, three grooves having a groove width of 2 mm and a depth of 7 μm were provided in the bonding portion 36 of the flange 35. The developing roller 15 has a positional accuracy of the flange 35 of 3 μm or less and a torque resistance of 5 Nm or more.

  When an image was formed by the image forming apparatus using the developing roller having this configuration, a good image having density unevenness rank 4 and no density unevenness in the circumferential direction was obtained. In addition, in the production under these conditions, the non-defective rate of the positional accuracy and the torque resistance was 100%.

Example 4
In the fourth embodiment, the small diameter portion 36 of the flange 35 is provided with an oblique groove in the axial direction (FIG. 8B), the gap G with the developing sleeve 32 is 20 μm, the diameter D1 of the resin sphere 51 and the metal sphere 52 The diameter D2 was set to D1 = 28 μm and D2 = 15 μm, respectively. Further, the flange 35 coated with a paint 53 in which the blending amount of the resin sphere 51 and the metal sphere 52 is set to resin sphere 51: metal sphere 52 = 50%: 15% is provided in a groove on the circumference of the small-diameter portion 36 of the flange 35. Using. Further, the developing roller 15 in which the developing sleeve 32 is made of aluminum having an outer diameter of φ25 mm was formed. The resin sphere 51 contained a cyanoacrylate-based instantaneous adhesive, and the resin layer used urethane resin. The metal sphere 52 was made of aluminum. The inner diameter of the developing sleeve 32 was φ23.6 mm, and the outer diameter of the large diameter portion 37 of the flange 35 inserted into the developing sleeve was φ23.59 mm. Further, the adhesive portion 36 of the flange 35 was provided with eight grooves having a groove width of 2 mm and a depth of 14 μm. The developing roller 15 has a positioning accuracy of the flange 35 of 2 μm or less and a torque resistance of 4 Nm or more.

  When an image was formed by the image forming apparatus using the developing roller having this configuration, a good image having density unevenness rank 4 and no density unevenness in the circumferential direction was obtained. In addition, in the production under these conditions, the non-defective rate of the positional accuracy and the torque resistance was 100%.

(Example 5)
In Example 5, the small-diameter portion 36 of the flange 35 is provided with a spiral groove, the gap G with the developing sleeve is 10 μm, the diameter D1 of the resin sphere 51 and the diameter D2 of the metal sphere 52 are D1 = 15 μm, D2 = 8 μm. Further, the flange 35 coated with a paint 53 in which the blending amount of the resin sphere 51 and the metal sphere 52 is set to resin sphere 51: metal sphere 52 = 50%: 15% is provided in a groove on the circumference of the small-diameter portion 36 of the flange 35. Using. Further, the developing roller 15 in which the developing sleeve 32 is made of aluminum having an outer diameter of φ25 mm was formed. The resin sphere 51 contained a cyanoacrylate-based instantaneous adhesive, and the resin layer used urethane resin. The metal sphere 52 was made of aluminum. The inner diameter of the developing sleeve is φ23.6 mm, the outer diameter of the large diameter portion 37 of the flange 35 inserted into the developing sleeve 32 is φ23.59 mm, and the spiral groove has a width of 2 mm and a depth of 7 μm. The developing roller 15 has a flange positioning accuracy of 2 μm or less and a torque resistance of 4 Nm or more.

  When an image was formed by the image forming apparatus using the developing roller 15 having this configuration, a good image having density unevenness rank 4 and no density unevenness in the circumferential direction was obtained. In addition, in the production under these conditions, the non-defective rate of the positional accuracy and the torque resistance was 100%.

(Comparative Example 1)
In Comparative Example 1, the outer diameter of the large diameter portion 37 of the flange 35 was set to n6, and the fitting coupling was performed by press-fitting only into the developing sleeve 32. (Outer diameter φ25 and inner diameter φ23.5 of the developing sleeve 32, no large diameter corresponding portion 32a. Outer diameter φ23.58 of the large diameter portion 37 of the flange 35). In this case, the state in which the flange 35 is bent and inserted into the developing sleeve 32 occurs at the start of press-fitting, and the developing roller 15 with satisfactory torque resistance but poor position accuracy was produced. With this developing roller, an abnormal image with uneven density in the circumferential direction was generated and became defective. The non-defective product rate of the positioning accuracy of the developing roller obtained under the above conditions was 96%, and the non-torque resistant product rate was 98%.

(Comparative Example 2)
In comparative example 2, the shaft grade of the outer diameter of the large diameter portion 37 in the flange 35 is set to h5, and the coupling is performed by fitting the sliding grade, and the cyanoacrylate instantaneous adhesive is applied between the developing sleeve 32 and the flange 35. Thus, a developing roller was manufactured. (Outer diameter φ25 and inner diameter φ23.5 of the developing sleeve 32, no large diameter corresponding portion 32a. Outer diameter φ23.492 of the large diameter portion 37 of the flange 35). In this case, due to the variation in the adhesive strength of the adhesive, the developing roller 15 with a low torque resistance was achieved although the positional accuracy was satisfactory. In this developing roller 15, since the coupling strength between the flange and the developing sleeve is insufficient, the coupling portion breaks with time and becomes defective. The non-defective product rate of the positional accuracy of the developing roller obtained under the above conditions was 100%, and the non-defective torque rate was 98%. Further, 2% of defects due to the protrusion of the adhesive occurred.

(Comparative Example 3)
In the comparative example 3, the flange 35 is joined by engaging the sliding class fitting with the shaft class of the outer diameter of the large-diameter portion 37 in the flange 35 as h5 and caulking at the end of the developing sleeve 32. A developed developing roller was produced. (Outer diameter φ25 and inner diameter φ23.5 of the developing sleeve 32, no large diameter corresponding portion 32a. Outer diameter φ23.492 of the large diameter portion 37 of the flange 35). In this case, the torque resistance is satisfied by performing the caulking, but the position of the flange 35 slightly changes due to the caulking, and the developing roller has a poor positional accuracy. This developing roller is defective because an abnormal image with uneven density in the circumferential direction is generated. The non-defective product rate of the positional accuracy of the developing roller obtained under the above conditions was 93%, and the non-torque resistant product rate was 100%.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various deformation | transformation and application are possible. Of course, such modifications and applications are included in the scope of the present invention as long as the configuration of the present invention is provided.

  For example, in 2nd Embodiment shown in FIG. 7, it is good also as a structure by which some or all convex parts 36b other than the convex part 36b between the step parts 36a were deleted.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 6Y, 6C, 6M, 6K Process cartridge 13 Developing apparatus 15 Developing roller 32 Developing sleeve 32a Large diameter corresponding part 35 Flange 36 Small diameter part 37 Large diameter part 38 Rotating shaft 51 Resin sphere 52 Metal sphere 53 Paint

JP 2011-17901 A JP-A-3-43479 JP 2009-53310 A

Claims (9)

In a developing roller comprising a cylindrical developing sleeve, and a flange that is inserted into and fixed to the opening end of the developing sleeve,
The flange includes a small-diameter small-diameter portion provided on the front end side inserted into the developing sleeve, a large-diameter portion larger in diameter than the small-diameter portion provided on the rear end side from the small-diameter portion, and the large-diameter portion. A rotating shaft that is provided on the rear end side and that rotates the developing sleeve is provided coaxially;
The developing sleeve is provided with a large-diameter corresponding portion into which the large-diameter portion is fitted when the flange is inserted at an opening end portion thereof.
The small-diameter portion has a diameter that forms a gap G between the small-diameter portion and the large-diameter corresponding portion when the paint is applied before insertion of the flange into the opening end portion of the developing sleeve.
The paint has a larger diameter than the gap G and contains an adhesive inside. The paint is crushed and ruptured when the flange is inserted into the opening end of the developing sleeve, and the adhesive is put into the gap. Resin spheres to be diffused and metal spheres having substantially the same diameter as the gap are dispersed,
The developing sleeve and the flange are coupled by fitting the large diameter portion to the large diameter corresponding portion and bonding the small diameter portion with the adhesive to the large diameter corresponding portion. Developing roller.   2. The developing roller according to claim 1, wherein at least one step portion is formed in the small diameter portion, and the paint is applied to the step portion.   3. The developing roller according to claim 1, wherein at least one groove is provided in a circumferential direction of the small diameter portion of the flange, and the paint is applied to each groove. Development roller.   3. The developing roller according to claim 1, wherein a plurality of grooves are provided in the axial direction of the small diameter portion of the flange, and the coating material is applied to each groove. .   3. The developing roller according to claim 1, wherein a plurality of grooves inclined obliquely with respect to the axial direction of the small-diameter portion of the flange are provided, and the paint is applied to each of the grooves. A developing roller characterized by.   3. The developing roller according to claim 1, wherein a spiral groove is provided in the small diameter portion of the flange, and the coating material is applied to each groove.   A developing device comprising the developing roller according to claim 1.   A process cartridge comprising: a developing device including the developing roller according to claim 1.   An image forming apparatus, comprising: a developing device including the developing roller according to claim 1.

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