JP2009276644A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device able to reduce friction between the rotation shaft of a developer carrier and ball bearings pivotally supporting the rotation shaft so that it freely rotates, and to provide an image forming apparatus that has the developing device. <P>SOLUTION: The developing device includes: the developer carrier for holding developer with which a latent image held on a latent image carrier is developed; and the ball bearings 30 disposed in the body of the device pivotally supporting the rotation shaft 81 of the developer carrier so that it freely rotates. In the developing device, a sandwiching means for sandwiching an inner ring 31 by pressing side faces of ball bearings 30 in the direction which they intersect the axis of the rotation shaft for the inner ring 31 is disposed on the rotation shaft 81 so as to be rotatable integrally with the rotation shaft 81. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and an image forming apparatus including the developing device.

The rotation shaft of the developing roller, which is a developer carrying member for carrying the developer provided in the developing device used in this type of image forming apparatus, is rotatably supported by a bearing member provided in the developing device main body. (Patent Document 1 etc.). In addition, when a slide bearing is used as the bearing member, the rotating shaft of the developing roller and the inner peripheral surface of the bearing member rub against each other, and the developing roller rotating shaft and the bearing member are gradually used as the developing device is used over time. May be worn and deformed. When the rotating shaft and the bearing member of the developing roller are worn and deformed in this manner, the play between the developing roller and the bearing member increases, leading to poor driving of the developing roller and instability of the driving torque of the developing roller. . Further, since the backlash between the developing roller and the bearing member increases, the developing gap, which is the distance between the developing roller surface and the latent image carrier surface, cannot be maintained at a predetermined distance, and good development cannot be performed.
Therefore, in many cases, a ball bearing is used as a bearing member, and the rotating shaft of the developing roller or the bearing is supported by fitting the rotating shaft of the developing roller into the inner ring of the ball bearing and rotatably supporting the rotating shaft. The member is made hard to wear.

JP 2006-242990 A

  However, even when a ball bearing is used as a bearing member, there is a gap between the inner peripheral surface of the inner ring of the ball bearing and the rotating shaft of the developing roller so that the rotating shaft of the developing roller can be easily fitted into the inner ring of the ball bearing. Is provided. For this reason, the inner ring portion of the ball bearing cannot reliably rotate following the rotation of the rotating shaft of the developing roller due to this gap, and the rotating shaft of the developing roller and the inner ring portion of the ball bearing may rotate idle. As described above, when the rotation shaft of the developing roller and the inner ring portion of the ball bearing idle, there arises a problem that the rotation shaft of the developing roller and the inner peripheral surface of the inner ring portion of the ball bearing rub against each other and wear.

  The present invention has been made in view of the above problems, and the object thereof is a developing device capable of reducing wear of a rotating shaft of a developer carrying member and a ball bearing that rotatably supports the rotating shaft. And providing an image forming apparatus including the developing device.

In order to achieve the above object, the invention of claim 1 is directed to a developer carrying member that carries a developer for developing a latent image carried on a latent image carrying member, and a rotating shaft of the developer carrying member. In a developing device provided with a ball bearing provided on a main body that freely supports the shaft, the holding means for holding the inner ring portion by pressing the side surface intersecting the rotation axis direction of the inner ring portion of the ball bearing is rotated. The rotating shaft is provided integrally with the shaft so as to be rotatable.
According to a second aspect of the present invention, there is provided the developing device according to the first aspect, wherein the holding means is provided on an elastic member in contact with a side surface of the inner ring portion, and on a side surface opposite to the side surface of the inner ring portion in contact with the elastic member. The inner ring portion is pressed in the direction of the rotation axis toward the step portion by the restoring force of the elastic member provided by being compressed on the rotation shaft. The portion is held between the step portion and the elastic member.
According to a third aspect of the present invention, in the developing device of the second aspect, the elastic member is a cylindrical rubber member.
According to a fourth aspect of the present invention, there is provided the developing device according to the third aspect, further comprising buckling deformation preventing means for preventing the rubber member from buckling.
According to a fifth aspect of the present invention, in the developing device according to the fourth aspect, the buckling deformation preventing means is a cover member that covers the rubber member in contact with the surface.
According to a sixth aspect of the invention, in the developing device of the second aspect, the elastic member is a spring member.
According to a seventh aspect of the present invention, in the developing device of the sixth aspect, the anti-slip member for preventing the end surface of the spring member and the side surface of the inner ring portion from slipping is provided between the end surface of the spring member and the side surface of the inner ring portion. It is characterized by being provided between.
According to an eighth aspect of the present invention, there is provided an image forming apparatus comprising: a latent image carrier that carries a latent image; and a developing unit that develops the latent image carried on the latent image carrier. The developing device according to Item 1, 2, 3, 4, 5, 6 or 7 is used.
The invention according to claim 9 is the image forming apparatus according to claim 8, wherein a plurality of bearings rotatably supports axial ends of the rotation shaft of the latent image carrier and the rotation shaft of the developer carrier. And a bearing member that supports at least the rotation shaft of the developer carrier provided on the support plate member is a ball bearing, and the ball provided on the support plate member. A second holding means for pressing the side surface of the inner ring portion of the bearing to hold the inner ring portion is provided on the rotation shaft of the developer carrying member.
According to a tenth aspect of the present invention, there is provided an image forming apparatus comprising a latent image carrier that carries a latent image and a developing unit that develops the latent image carried on the latent image carrier. The developing device according to Item 2, 3, 4, 5, 6 or 7 is used, and the latent image carrier is set such that a distance between the surface of the latent image carrier and the surface of the developer carrier is a predetermined distance. A support plate member for positioning and supporting the rotation axis of the developer and the rotation shaft of the developer carrier, and the rotation shaft of the latent image carrier and the rotation shaft of the developer carrier provided on the support plate member, respectively. A plurality of bearing members that rotatably support one end of the shaft in the axial direction, and the bearing member that supports at least the rotation shaft of the developer carrying member provided on the support plate member is a ball bearing. A ball bearing provided on the main body of the apparatus and a ball bearing provided on the support plate member are coaxially opposed to each other. The elastic member is in contact with the side surface of the inner ring portion of the ball bearing provided on the support plate member, the other end being in contact with the side surface of the inner ring portion of the ball bearing provided in the developing device main body, A contact member provided on the rotary shaft is in contact with a side surface of an inner ring portion of a ball bearing provided on the support plate member on the side opposite to the side surface on which the elastic member is in contact, and the elastic member is The inner ring portion of the ball bearing provided on the support plate member is held between the elastic member and the corresponding contact member by pressing the inner ring portion of the ball bearing provided on the support plate member in the axial direction toward the corresponding contact member. It is comprised so that it may carry out.
According to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, a partition member is provided on the rotating shaft between a ball bearing provided in the developing device main body and a ball bearing provided in the support plate member. The elastic member is divided and provided so as to sandwich the partition member.

  In the present invention, the inner ring portion of the ball bearing is held by the holding means provided on the rotary shaft so as to be rotatable integrally with the rotary shaft of the developer carrier. As a result, the inner ring portion of the ball bearing and the rotation shaft of the developer carrier are idled rather than the configuration in which the inner ring portion of the ball bearing is not held by the holding means simply by inserting the rotation shaft into the inner ring portion of the ball bearing. Can be difficult. Thus, the inner ring portion of the ball bearing and the rotation shaft of the developer carrier are idled rather than the configuration in which the inner ring portion of the ball bearing is merely inserted into the inner ring portion of the ball bearing and the inner ring portion is not held by the holding means. Wear caused by rubbing between the inner peripheral surface of the portion and the rotating shaft can be reduced.

  As described above, the present invention has an excellent effect that it is possible to reduce the wear of the rotating shaft of the developer carrying member and the ball bearing that rotatably supports the rotating shaft.

Hereinafter, an embodiment of an electrophotographic printer (hereinafter simply referred to as a printer 100) will be described as an image forming apparatus to which the present invention is applied.
First, the basic configuration of the printer 100 will be described. FIG. 2 is a schematic configuration diagram illustrating the printer 100 according to the present embodiment.
As shown in FIG. 2, the printer 100 includes four image forming process units 10Y, 10C, 10M, and 10K for yellow, cyan, magenta, and black (hereinafter referred to as Y, C, M, and K). These use Y, C, M, and K toners of different colors as image forming substances for forming an image, but the other configurations are the same. Taking the Y image forming process unit 10Y for generating a Y toner image as an example, around the photoreceptor 1Y that is rotated in the counterclockwise direction (arrow A direction in the figure) by a driving means (not shown). , A cleaning device 6Y, a charge eliminating unit (not shown), a charging device 2Y, an optical writing device 3Y, a developing device 4Y, and the like.

  The charging device 2Y disposed so as to face the photoreceptor 1Y is a charging charger in which a charging bias is applied to a charging wire from a charging bias power source (not shown). Then, the charging device 2Y generates a discharge with the photoreceptor 1Y, so that the surface of the photoreceptor 1Y is uniformly charged. Instead of the charging device 2Y using the charging charger, a charging roller may be disposed so as to be in contact with the photosensitive member 1Y or opposed to the photosensitive member 1Y with a predetermined gap to uniformly charge the photosensitive member 1. Good.

  The surface of the photoreceptor 1Y that is uniformly charged by the charging device 2Y is exposed and scanned by the scanning light emitted from the optical writing device 3Y and carries a latent image for Y. The optical writing device 3Y emits laser light or LED light modulated based on image information sent from an external personal computer or the like.

The developing device 4Y, which is a developing means, is a developing region facing the photoreceptor 1Y. By using a well-known technique, Y toner is attached to the latent image carried on the surface of the photoreceptor 1Y, thereby developing the latent image and developing the Y toner image. Get. This Y toner image is primarily transferred to the intermediate transfer belt 7.
The developing device 4Y shown in FIG. 2 includes two developing rollers, an upper developing roller 411Y and a lower developing roller 412Y, as developing rollers. When developing the latent image on the photoconductor 1Y using two developing rollers to increase the peripheral speed of the photoconductor 1Y, the latent image is more reliably generated than when developing with one developing roller. Development can be performed.

  The cleaning device 6Y removes transfer residual toner attached to the surface of the photoreceptor 1Y after the primary transfer process. The cleaning device 6 is provided with a cleaning brush so as to contact and rub against the surface of the photosensitive member downstream of the cleaning blade with respect to the rotation direction of the photosensitive member, and further provided with a toner recovery roller in contact with the cleaning brush. A configuration in which toner is removed from the collection roller by a rubber blade can be applied. The cleaning device is not limited to this configuration. The surface of the photoreceptor 1Y that has been subjected to the cleaning process by the cleaning device 6Y is neutralized by a neutralizing unit such as a neutralizing lamp (not shown) to prepare for the next image formation.

  In FIG. 2, C, M, and K toner images are similarly formed on the photoreceptors 1 </ b> C, M, and K in the image forming process units 10 </ b> C, M, and K for other colors, and are formed on the intermediate transfer belt 7. Intermediate transfer.

  Below the image forming process units 10Y, 10C, 10M, and 10K, the intermediate transfer belt 7 that is a toner image carrier is stretched and moved endlessly in the clockwise direction (the arrow B direction in the figure). A unit 70 is provided. The transfer unit 70 serving as transfer means includes an intermediate transfer belt 7, a secondary transfer counter roller 71, two stretching rollers 7a, 7b, and four primary transfer chargers 5Y, 5C, 5M, 5F as primary transfer members. K, a secondary transfer roller 8, a belt cleaning device (not shown), and the like.

  The intermediate transfer belt 7 is stretched by a first stretching roller 7a, a second stretching roller 7b, and a secondary transfer counter roller 71 disposed on the inner side of the loop. One is driven to rotate endlessly clockwise in the figure.

  The four primary transfer chargers 5Y, 5C, 5M, and 5K are opposed to the photoreceptors 1Y, 1C, 1M, and 1K with the intermediate transfer belt 7 moved endlessly in this way, and are for Y, C, M, and K, respectively. A primary transfer portion is formed. Then, a transfer bias having a polarity opposite to that of the toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 7. The intermediate transfer belt 7 sequentially passes through the primary transfer portions for Y, C, M, and K along with the endless movement thereof, and the surface of the intermediate transfer belt 7 is placed on the photoreceptors 1Y, 1C, 1M, and 1K. Y, C, M, and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 7. The primary transfer member constituting the primary transfer unit is not limited to the transfer charger, and is, for example, a primary transfer roller that forms a primary transfer nip by sandwiching the intermediate transfer belt 7 with the photoreceptor 1. Also good.

  A secondary transfer roller 8 to which a secondary transfer bias output from a power source (not shown) is applied is disposed outside the loop of the intermediate transfer belt 7, which is connected to a secondary transfer counter roller 71 inside the belt loop. A secondary transfer nip is formed by sandwiching the intermediate transfer belt 7 therebetween.

  A sheet feeding cassette (not shown) is disposed below the transfer unit 70. In this paper feed cassette, a plurality of recording papers P as recording media are accommodated in a stack of recording papers, and the uppermost recording paper P is placed in a paper feeding path (not shown) at a predetermined timing. Send it out. A registration roller pair 81 is disposed at the end of the paper feed path. The registration roller pair 81 temporarily stops the rotation of both rollers as soon as the recording paper P conveyed between the rollers rotating while abutting each other is sandwiched. Then, the recording paper P is sent toward the secondary transfer nip at a timing at which the recording paper P can be synchronized with the four-color toner image on the intermediate transfer belt 7.

  The four-color toner image formed on the intermediate transfer belt 7 has a secondary transfer electric field formed between the secondary transfer roller 8 to which a secondary transfer bias is applied and the grounded secondary transfer counter roller 71. Due to the influence of the nip pressure, batch transfer is performed onto the recording paper P in the secondary transfer nip. Then, combined with the white color of the recording paper P, a full color toner image is obtained.

  Untransferred toner that has not been transferred to the recording paper P adheres to the intermediate transfer belt 7 after passing through the secondary transfer nip. This is removed by a belt cleaning device (not shown) in which the intermediate transfer belt 7 is sandwiched between the stretching roller 7a.

  A fixing device (not shown) is disposed on the left side of the secondary transfer nip in the drawing. As is well known in electrophotographic image forming apparatuses, this fixing device fixes a toner image on a recording sheet by pressurization or heating.

  In the printer 100 having the above basic configuration, the four image forming process units 10Y, 10C, 10M, and 10K have toner images on the endlessly moving surfaces of the photoreceptors 1Y, 1C, 1M, and 1K that are latent image carriers. It functions as a toner image forming means for forming the toner. Further, the combination of the four image forming process units 10Y, 10C, 10M, and 10K and the transfer unit 70 functions as a toner image forming unit that forms a toner image on the endlessly moving surface of the intermediate transfer belt 7 that is a toner image carrier. is doing.

  Next, an image forming apparatus that integrally supports the developing devices 4Y, C, M, and K and the photoreceptors 1Y, C, M, and K included in the four image forming process units 10Y, 10C, 10M, and 10K. The image forming units 200Y, 200C, 200M, and 200K will be described. Since the image forming units 200Y, 200C, 200M, and 200K have the same configuration except that the colors of the toners used are different, the following description omits Y, C, M, and K.

  FIG. 3 is a schematic sectional view of the image forming unit 200. The image forming unit 200 according to the present embodiment integrally supports a cleaning device 6, a static eliminator (not shown), and a charging device 2 as image forming members other than the developing device 4 and the photoreceptor 1, and is attached to and detached from the printer 100 main body. It is possible. The image forming unit 200 is not configured to integrally support the optical writing device 3Y that is a latent image forming unit, but a member constituting the latent image forming unit is also detachable from the printer 100 main body as the image forming unit 200. It may be configured.

  The developing device 4 includes a supply screw 51 that supplies developer to an upper developing roller 411 and a lower developing roller 412 that are two developing rollers while conveying the developer from the near side to the far side in FIG. Further, a collecting screw 52 is supplied to both developing rollers and collects the developer after passing through a developing region which is a facing portion between both developing rollers and the photoreceptor 1 and transports from the front side to the back side in FIG. Is provided. Furthermore, a circulation screw 53 is provided that circulates the developer by delivering the developer reaching the downstream end in the transport direction of the collection screw 52 to the upstream end in the transport direction of the supply screw 51. The circulation screw 53 extends from the rear side to the front side so that the rear end portion in FIG. 3 of the developing device 4 has the same height as the recovery screw 52 and the front end portion has the same height as the supply screw 51. It arrange | positions so that it may become diagonally upward. Here, the space in which the supply screw 51 of the developing device 4 is arranged is circulated in the supply conveyance path 51a, the space in which the collection screw 52 is arranged is collected in the collection conveyance path 52a, and the space in which the circulation screw 53 is arranged. Let it be a conveyance path 53a. Further, an upper developing roller 411 and a lower developing roller 412 are arranged, and a space facing the photoreceptor 1 is defined as a developing chamber 59. Further, the developing device 4 includes a catch roller 56 that faces the photosensitive member 1 below the lower developing roller 412.

  The upper developing roller 411 and the lower developing roller 412 disposed below the upper developing roller 411 are each composed of a non-magnetic pipe that is driven to rotate in the clockwise direction in the figure by a driving means such as a motor or a drive transmission system (not shown). It has a sleeve and a magnet roller (not shown) that is included so as not to be rotated.

  The developing chamber 59 that houses the upper developing roller 411 and the lower developing roller 412 has an opening in the wall facing the photoconductor 1, and from there, the peripheral surface of the developing sleeve of the two developing rollers 41. Some are exposed. A supply conveyance path 51a and a collection conveyance path 52a communicate with each other on the opposite side of the developing chamber 59 from the opposite side to the photosensitive member 1 over the entire area in the axial direction of both developing rollers. The supply conveyance path 51a is disposed directly above the collection conveyance path 52a in the vertical direction, and both the supply conveyance path 51a and the collection conveyance path 52a extend over the entire area in the longitudinal direction on the right side (photoconductor side) in the drawing. It communicates with the developing chamber 59.

  The supply screw 51 disposed in the supply conveyance path 51a has a posture extending in the horizontal direction in the same manner as the photosensitive member 1 and both developing rollers. The supply screw 51 includes a rod-shaped rotating shaft member and a screw blade that is spirally provided on the circumferential surface of the rod-shaped rotating shaft member. The supply screw 51 is counterclockwise in FIG. It is rotationally driven integrally in the turning direction.

  The recovery screw 52 accommodated in the recovery conveyance path 52 a is also in a posture extending in the horizontal direction, like the photosensitive member 1, both developing rollers, and the supply screw 51. Then, the rotating shaft member and the screw blade are integrally rotated in the clockwise direction in the drawing by a driving means (not shown).

  A circulation conveyance path 53a is adjacent to the supply conveyance path 51a and the collection conveyance path 52a on the side opposite to the developing chamber 59 side. Unlike the other developer conveyance paths, the circulation conveyance path 53a is formed to extend in a posture inclined from the horizontal direction. The circulating screw 53 in which screw blades are erected on the peripheral surface of the rotating shaft member also extends in an inclined posture in the circulating conveyance path 53a, and is rotated counterclockwise in the drawing by a driving means (not shown). It is rotationally driven in the direction. The circulation conveyance path 53a is largely partitioned from the supply conveyance path 51a and the collection conveyance path 52a by a partition wall 58. However, the opening provided in the partition wall 58 partially communicates with the supply conveyance path 51a and the collection conveyance path 52a.

  In the supply conveyance path 51a, the developer (not shown) held in the blades of the supply screw 51a is conveyed from the front side to the back side in the direction orthogonal to the drawing sheet as the supply screw 51 rotates. . In the course of this conveyance, the developer is sequentially supplied to the developing sleeve (hereinafter referred to as the upper developing sleeve) of the upper developing roller 411 in the developing chamber 59. Then, it is pumped up to the upper developing sleeve by the magnetic force of the magnet roller in the upper developing sleeve.

  The developer pumped up by the upper developing sleeve is regulated in layer thickness on the upper developing sleeve by a doctor blade 57 whose tip is opposed to the surface of the upper developing sleeve via a predetermined gap. Then, the toner is transported to the first development area facing the photosensitive member 1 and contributes to development here.

  The developer transported to the vicinity of the downstream end of the supply screw 51 in the agent transport direction (near the rear end in the figure) without being drawn up by the upper developing sleeve is not shown provided on the bottom wall of the supply transport path 51a. Falls into the collection conveyance path 52a.

  Further, as the upper developing sleeve rotates, the developer that has been transported to the first developing area where the upper developing sleeve and the photosensitive member 1 face each other and contributes to the development is then moved to the first developing region along with the rotation of the upper developing sleeve. Pass through the development area. Then, the toner is transferred to a developing sleeve (hereinafter referred to as a lower developing sleeve) of a lower developing roller 412 disposed below the upper developing roller 411. Thereafter, with the rotation of the lower developing sleeve, the lower developing sleeve and the photosensitive member 1 are sent to the second developing region facing each other, where they contribute again to the development. The developer that has completed the second development step is transported to a communication position between the developing chamber 59 and the recovery transport path 52a. Then, after separating from the surface of the lower developing sleeve due to the influence of the repulsive magnetic field formed by the magnet roller of the lower developing roller 412, it falls into the collection conveyance path 52 a.

  After passing through the second developing area along with the rotation of the lower developing sleeve, the developer that has separated from the surface of the lower developing sleeve at a position relatively distant from the recovery conveyance path 52a was disposed immediately below the lower developing sleeve. By the rotational force of the catch roller 56, it is conveyed toward the collection conveyance path 52a.

  In the collection conveyance path 52 a, the developer (not shown) held in the blades of the collection screw 52 is conveyed from the near side to the back side in the direction orthogonal to the drawing sheet as the collection screw 52 rotates. In this conveyance process, toner is supplied to the developer in the collection conveyance path 52a by a toner supply device (not shown). Further, the developer falling from the drop opening of the supply conveyance path 51a is taken in. Thereafter, the developer transported to the vicinity of the downstream end of the recovery screw 52 in the agent transport direction (near the rear end in the figure) passes through the opening provided in the partition wall 58 and enters the circulation transport path 53a. enter in.

  The developer that has entered the circulation conveyance path 53a is taken into the upstream end of the circulation screw 53a in the agent conveyance direction. Then, as the circulating screw 53a is disposed in an obliquely upward posture from the upstream side in the agent transport direction to the downstream side in the agent transport direction, it is transported with an ascending gradient. When the developer is transported to the vicinity of the downstream end of the circulation screw 53 in the agent transport direction, the developer passes through the opening provided in the partition wall 58 and is returned to the supply transport path 51a. And it is taken in into the agent conveyance direction upstream edge part of the supply screw 51. FIG.

[Example 1]
Next, features of the present invention will be described.

  In the developing device 4, a two-component developer composed of toner and carrier circulates in the case 62 as shown in FIG. 3. FIG. 4 shows an example of the structure of the developing roller. FIG. 5 is a perspective view of the developing device 4. The developing sleeve is formed in a hollow shape, and a magnet roller M is fixedly disposed therein. A shaft for fixing the internal magnet roller M to one end of the developing sleeve is fixed to a bearing portion of the case 62. The other of the photosensitive member 1 is such that the sleeve shaft 81 has a predetermined gap between the ball bearing 30 provided on the case 62 as shown in FIG. 1 and the developing gap between the photosensitive member surface and the developing roller surface. A ball bearing 40 provided on a support plate 69 for positioning and supporting the rotation shaft and the sleeve shaft 81 is rotatably supported. Then, it is rotatably supported by a coupling gear (not shown) attached to the distal end portion of the sleeve shaft 81, and is rotationally driven via a gear 82 that transmits driving from a driving means (not shown).

  Between the ball bearing 30 and the ball bearing 40 of the sleeve shaft 81, elastic tubes 66 and 68 for applying a load in the thrust direction to the inner rings 31 and 41 of the ball bearings 30 and 40 are arranged as shown in FIG. It is arranged in a compressed state with a gap. As shown in FIG. 1, a gear 82 that transmits driving is fitted to the sleeve shaft 81 in contact with the side surface of the inner ring 41 of the ball bearing 40, and the gear 82 does not come off the sleeve shaft 81. A parallel pin 83 for retaining is fitted.

  The inner diameter of the elastic tube 66 provided on the sleeve shaft 81 is small so that the elastic tube 66 is in close contact with the surface of the sleeve shaft 81. The elastic tube 66 is compressed in the axial direction (thrust direction) of the sleeve shaft 81 by the side surface of the inner ring 31 of the ball bearing 30 and the side surface of the collar 67. Similarly, the inner diameter of the elastic tube 68 provided on the sleeve shaft 81 is small so that the elastic tube 7 is in close contact with the surface of the sleeve shaft 81. The elastic tube 68 is compressed in the axial direction (thrust direction) of the sleeve shaft 81 by the side surface of the inner ring 41 of the ball bearing 40 and the side surface of the collar 67.

  The material and shape of the elastic tubes 66 and 68 are not particularly limited, and an elastic force that presses the inner rings 31 and 41 of the ball bearings 30 and 40 in the thrust direction can be generated. Any elastic body can be used as long as it is in close contact with the substrate, and a silicon tube is used in this embodiment.

  The collar 67 serves as a spacer for shortening the elastic tubes 66 and 68 and making the elastic tubes 66 and 68 difficult to buckle.

  In this embodiment, the collar 67 is formed from a synthetic resin. As the shape, both sides are flat as shown in FIG. 1, and the material is not particularly specified as long as the elastic tubes 66 and 68 have a compressible hardness. Further, regarding the width of the collar 67, the material of the elastic tubes 66 and 68 is selected so that the load in the thrust direction due to the elastic force of the elastic tubes 66 and 68 is sufficiently applied to the inner rings 31 and 41 of the ball bearings 30 and 40. Determined by width.

  As shown in FIG. 1, the inner ring 31 of the ball bearing 30 is held in a form that is held between an elastic tube 66 provided on the sleeve shaft 81 and a stepped portion 84 formed on the sleeve shaft 81. That is, the elastic tube 66 compressed by the sleeve shaft 81 presses one side surface of the inner ring 31 in the direction of the stepped portion by an elastic force (restoring force), and the stepped portion 84 presses the elastic tube 66. The inner ring 31 is received in contact with the other side surface of the inner ring 31. In this way, the inner ring 31 of the ball bearing 30 is held by the elastic tube 66 and the stepped portion 84 by the pressing force of the elastic tube 66. The position where the elastic body tube 66 and the stepped portion 84 are provided is opposite to that of FIG. 1 with the ball bearing 30 in between (the elastic tube 66 is on the left side of the ball bearing 30 and the stepped portion 84 is on the right side of the ball bearing 30 in FIG. ).

  Thus, the inner ring 31 of the ball bearing 30 is fixed to the sleeve shaft 81 in such a manner that the inner ring 31 of the ball bearing 30 is sandwiched from the side by the elastic tube 66 that is in close contact with the sleeve shaft 81 and the stepped portion 84 that is the sleeve shaft 81 itself. The inner ring 31 can be rotated by following the rotation of the sleeve shaft 81 with certainty. Therefore, it is possible to prevent the inner ring 51 and the sleeve shaft 81 from being worn by the inner ring 31 and the sleeve shaft 81 being idle and the inner peripheral surface of the inner ring 31 and the sleeve shaft 81 being rubbed against each other.

  The inner ring 41 of the ball bearing 40 is fitted into an elastic tube 68 provided on the sleeve shaft 81 as shown in FIG. 1 and a sleeve shaft 81 that transmits a driving force from a driving source (not shown) to the sleeve shaft 81. And is held by a driving force transmission gear 82. That is, the elastic tube 68 compressed by the sleeve shaft 81 presses one side surface of the inner ring 41 in the gear direction by an elastic force (restoring force), and the gear 82 is pressed by the elastic tube 68. The inner ring 41 is received in contact with the other side surface of the inner ring 41. Here, as shown in FIG. 1, the gear 82 is prevented from coming off from the sleeve shaft 81 by the parallel pin 83 which is a coming-off preventing member, so that the pressing force from the elastic tube 68 via the inner ring 41 is prevented. Is received by the gear 82. In this way, the inner ring 41 of the ball bearing 40 is held by the elastic tube 68 and the gear 82 by the pressing force of the elastic tube 68.

  As a result, the inner ring 41 of the ball bearing 40 is fixed to the sleeve shaft 81 from the side by the elastic tube 66 and the gear 82 that are in close contact with the sleeve shaft 81, and the sleeve shaft 81 is reliably rotated. The inner ring 41 can be rotated by being driven. Therefore, it is possible to suppress wear of the inner ring 41 and the sleeve shaft 81 due to the inner ring 41 and the sleeve shaft 81 being idle and the inner peripheral surface of the inner ring 41 and the sleeve shaft 81 being rubbed.

  Therefore, in this embodiment, since it is possible to suppress the backlash between the sleeve shaft 81 and the ball bearings 30 and 40, it is possible to cause driving failure of the developing roller and instability of driving torque of the developing roller. Further, it is possible to prevent the development gap between the developing roller surface and the photoreceptor surface from being maintained at a predetermined interval and preventing good development from being performed.

  Further, by increasing the frictional force generated between the elastic tubes 66 and 68 and the inner rings 31 and 41, the inner rings 31 and 31 can be rotated by being further driven by the rotation of the sleeve shaft 81. As the elastic tubes 66 and 68, it is desirable to use an elastic body made of a material that increases the frictional force.

  In the present embodiment, as described above, silicon tubes are used as the elastic body tubes 66 and 68, and the inner rings 31 and 41 of the ball bearings 30 and 40 can be pressed with a sufficient load in the thrust direction. Further, the frictional force generated between the elastic tubes 66 and 68 and the inner rings 31 and 41 can be increased.

  Further, the thrust tubes 66 and 68 may not be sufficiently loaded in the thrust direction, and the inner rings 31 and 41 and the sleeve shaft 81 may idle. In this case, if the elastic force is increased by gradually increasing the width of the elastic tubes 66, 68, the elastic tubes 66, 68 when the crushing amount of the elastic tubes 66, 68 reaches a certain ratio. Causes buckling deformation, and the load in the thrust direction is extremely reduced. Therefore, in order to prevent buckling deformation of the elastic tubes 66, 68, a cover for preventing buckling deformation of the elastic tubes 66, 68 is provided outside the collar 67 as shown in FIG. It may be provided around so as to cover it.

  In this embodiment, the stepped portion 84 and the gear 82 formed on the elastic tubes 66 and 68 and the sleeve shaft 81 are in contact with only the inner rings 31 and 41 of the ball bearings 30 and 40. This is because the outer rings 32 and 42 of the ball bearings 30 and 40 are fixed to the case 62 and the support plate 69 so as not to rotate. In other words, if the elastic body tubes 66 and 68 are in contact with the outer rings 32 and 42, the elastic body tubes 66 and 68 and the outer rings 32 and 42 rub against each other when the sleeve shaft 81 rotates, so that the elastic body tubes 66 and 68 are moved. This is because there is a risk of damage. Further, when the stepped portion 84 and the gear 82 are in contact with the outer rings 32 and 42, the stepped portion 84 and the gear 82 slidably contact with the outer rings 32 and 42 when the sleeve shaft 81 rotates, so that the stepped portion 84 and the gear 82. This is because the outer rings 32 and 42 may be damaged.

[Example 2]
In this embodiment, as shown in FIG. 7, a compression coil spring 80 is attached to the sleeve shaft 81 in a compressed state instead of the elastic tube used in the first embodiment. Further, the inner diameter of the compression coil spring 80 is made small so that the compression coil spring 80 is in close contact with the surface of the sleeve shaft 81.

  As shown in FIG. 7, the inner ring 31 of the ball bearing 30 is held by a compression coil spring 80 provided on the sleeve shaft 81 and a stepped portion 84 formed on the sleeve shaft 81. That is, the compression coil spring 80 that is provided by being compressed by the sleeve shaft 81 presses one side surface of the inner ring 31 toward the stepped portion by an elastic force (restoring force), and the stepped portion 84 is pressed by the compression coil spring 80. The inner ring 31 is received in contact with the other side surface of the inner ring 31. In this way, the inner ring 31 of the ball bearing 30 is held by the compression coil spring 80 and the stepped portion 84 by the pressing force of the compression coil spring 80.

  Thereby, the inner ring 31 of the ball bearing 30 is fixed to the sleeve shaft 81 in such a manner that the inner ring 31 of the ball bearing 30 is sandwiched from the side by the compression coil spring 80 that is in close contact with the sleeve shaft 81 and the stepped portion 84 that is the sleeve shaft 81 itself. The inner ring 31 can be rotated by following the rotation of the sleeve shaft 81 with certainty. Therefore, it is possible to suppress the inner ring 41 and the sleeve shaft 81 from being worn by the idle rotation of the inner ring 31 and the sleeve shaft 81 and the friction between the inner peripheral surface of the inner ring 31 and the sleeve shaft 81.

  Further, as shown in FIG. 7, the inner ring 41 of the ball bearing 40 is fitted into a compression coil spring 80 provided on the sleeve shaft 81 and a sleeve shaft 81 that transmits a driving force from a driving source (not shown) to the sleeve shaft 81. It is held in the form of being held by a driving force transmission gear 82. That is, the compression coil spring 80 provided by being compressed by the sleeve shaft 81 presses one side surface of the inner ring 41 in the gear direction by an elastic force (restoring force), and the gear 82 is pressed by the compression coil spring 80. The inner ring 41 is received in contact with the other side surface of 41. Here, as shown in FIG. 7, the gear 82 is prevented from coming off from the sleeve shaft 81 by the parallel pin 83 which is a slip-off preventing member, so that the pressing force from the compression coil spring 80 is applied via the inner ring 41. It is received by the gear 82. In this way, the inner ring 41 of the ball bearing 40 is held by the compression coil spring 80 and the gear 82 by the pressing force of the compression coil spring 80.

  Accordingly, the inner ring 41 of the ball bearing 40 is fixed from the side by the compression coil spring 80 and the gear 82 that are in close contact with the sleeve shaft 81, and the sleeve shaft 81 is reliably rotated. The inner ring 41 can be rotated by being driven. Therefore, it is possible to suppress wear of the inner ring 41 and the sleeve shaft 81 due to the inner ring 41 and the sleeve shaft 81 being idle and the inner peripheral surface of the inner ring 41 and the sleeve shaft 81 being rubbed.

  Therefore, in this embodiment, the inner ring 41 and the sleeve shaft 81 are prevented from being worn, and an increase in play between the sleeve shaft 81 and the ball bearings 30 and 40 can be suppressed. This may cause drive failure or instability of the driving torque of the developing roller, or the development gap, which is the distance between the developing roller surface and the photoreceptor surface, cannot be maintained at a predetermined interval, and good development cannot be performed. Can be suppressed.

  Further, as in this embodiment, the member that presses the inner ring 41 in the thrust direction is the compression coil spring 80, so that the compression coil spring 80 that measures the load when pressing the inner rings 31, 41 in the thrust direction is used. Therefore, a more stable design than the elastic tube used in Example 1 can be performed.

  Further, the end surface of the compression coil spring 80 may slide with respect to the side surfaces of the inner rings 31 and 41 of the ball bearings 30 and 40. Therefore, it is better to arrange the anti-slip member 90 between the end surface of the compression coil spring 80 and the side surfaces of the ball bearings 30 and 40 as shown in FIG. The anti-slip member 90 is preferably made of a material having a large friction coefficient, such as rubber.

  In this embodiment, the compression coil spring 80, the stepped portion 84 formed on the sleeve shaft 81, the gear 82, and the like are in contact with only the inner rings 31, 41 of the ball bearings 30, 40. This is because the outer rings 32 and 42 of the ball bearings 30 and 4 are fixed to the case 62 and the support plate 69 so as not to rotate. That is, if the compression coil spring 80 is in contact with the outer rings 32 and 42, the compression coil spring 80 and the outer rings 32 and 42 may rub against each other when the sleeve shaft 81 rotates, and the compression coil spring 80 and the outer rings 32 and 42 may be damaged. Because there is. Further, when the stepped portion 84 and the gear 82 are in contact with the outer rings 32 and 42, the stepped portion 84 and the gear 82 and the outer rings 32 and 42 are slid and rubbed when the sleeve shaft 81 is rotated, so that the stepped portion 84 and the gear 82 are rubbed. This is because there is a risk of damage to 82 and the outer rings 32 and 42.

As described above, according to the present embodiment, there are a developing roller that is a developer carrying member that develops a latent image carried on the photosensitive member 1 that is a latent image carrying member, and a rotation shaft of the developing roller. In a developing device 4 including a ball bearing 30 provided on a device main body that rotatably supports a sleeve shaft 81, a side surface of the inner ring 31 that is an inner ring portion of the ball bearing 30 that intersects the sleeve shaft axial direction is pressed. A gripping means for gripping the inner ring 31 is provided on the sleeve shaft 81 so as to be rotatable integrally with the sleeve shaft 81. Thereby, since the inner ring 31 of the ball bearing 30 is held by the holding means provided on the sleeve shaft 81, the sleeve shaft 81 is simply inserted into the inner ring 31 of the ball bearing 30 by the holding means. The inner ring 31 and the sleeve shaft 81 of the ball bearing 30 can be made more difficult to idle than the configuration in which the inner ring 31 is not held. Therefore, the inner ring 31 and the sleeve shaft 81 of the ball bearing 30 are idled more than the configuration in which the inner ring 31 of the ball bearing 30 is not clamped by the above-mentioned clamping means simply by inserting the sleeve shaft 81 into the inner ring 31 of the ball bearing 30. Thus, the wear caused by the friction between the inner peripheral surface of the inner ring 31 and the sleeve shaft 81 can be reduced.
Further, according to the present embodiment, the holding means includes an elastic member such as an elastic tube or a compression coil spring that is in contact with the side surface of the inner ring 31, and a sleeve that is in contact with the side surface opposite to the side surface of the inner ring 31 that is in contact with the elastic member. The inner ring 31 is pressed toward the stepped portion 84 in the axial direction of the sleeve by the restoring force of the elastic member provided by being compressed on the sleeve shaft 81. 84 and the elastic member. Thereby, the inner ring 31 of the ball bearing 30 can be fixed to the sleeve shaft 81 with a simple configuration.
Further, according to the present embodiment, since the elastic tube 66 is a cylindrical rubber member, the inner rings 31, 41 of the ball bearings 30, 40 can be pressed with a sufficient load in the thrust direction, and the sleeve shaft 81 can be brought into close contact with the surface, and the frictional force generated between the elastic tubes 66 and 68 and the inner rings 31 and 41 can be increased. Therefore, the inner ring 31 can be rotated by following the rotation of the sleeve shaft 81.
Further, according to the present embodiment, by having the buckling deformation preventing means for preventing the buckling deformation of the elastic tube 66, the load in the thrust direction is extremely applied to the elastic tube 66 due to the buckling deformation of the elastic tube 66. Can be suppressed.
In addition, according to the present embodiment, the buckling deformation preventing means is a cover member that covers the elastic tube 66 while being in contact with the surface of the elastic tube 66, so that it is possible to easily prevent the elastic tube 66 from buckling. .
Further, according to the present embodiment, since the elastic member is the compression coil spring 80 that is a spring member, it is possible to use a compression coil spring 80 that has previously measured the load when pressing the inner ring 31 in the thrust direction. A more stable design than that of the elastic tube 66 can be performed.
Further, according to the present embodiment, the slip preventing member 90 that prevents the end surface of the compression coil spring 80 and the side surface of the inner ring 31 from slipping is provided between the end surface of the compression coil spring 80 and the side surface of the inner ring 31, thereby In addition, since the inner ring 31 can be held by the compression coil spring 80 and the stepped portion 84, the inner ring 31 can be rotated more reliably following the rotation of the sleeve shaft 81.
In addition, according to the present embodiment, a printer that is an image forming apparatus that includes a photosensitive member 1 that is a latent image carrier that carries a latent image, and a developing unit that develops the latent image carried on the photosensitive member 1. 100, by using the developing device 4 of the present invention as the developing means, the driving failure of the developing roller or the unstable driving torque of the developing roller may be caused, or the distance between the developing roller surface and the photosensitive member surface may be increased. It can be suppressed that a certain development gap cannot be maintained at a predetermined interval and good development cannot be performed.
Further, according to the present embodiment, the support plate 69 which is a support plate member provided with a bearing portion that rotatably supports one end in the axial direction of each of the rotation shaft of the photosensitive member 1 and the sleeve shaft 81 of the developing roller is provided. The bearing portion that supports at least the sleeve shaft 81 provided on the support plate 69 is a ball bearing 40, and the inner ring 41 is held by pressing the side surface of the inner ring 41 of the ball bearing 40 provided on the support plate 69. Two gripping means are provided on the sleeve shaft 81. Thereby, since the inner ring 41 of the ball bearing 40 is held by the second holding means provided on the sleeve shaft 81, the inner ring 41 is reliably driven by the rotation of the sleeve shaft 81 via the second holding means. Can be rotated. Therefore, it is possible to prevent the inner ring 41 and the sleeve shaft 81 of the ball bearing 40 from spinning idle. Therefore, it is possible to prevent the inner ring 41 and the sleeve shaft 81 from rubbing due to sliding of the inner ring 41 of the ball bearing 40 and the sleeve shaft 81 due to the idle rotation of the inner ring 41 and the sleeve shaft 81. Can do.
In addition, according to the present embodiment, a printer that is an image forming apparatus that includes a photosensitive member 1 that is a latent image carrier that carries a latent image, and a developing unit that develops the latent image carried on the photosensitive member 1. 100, the developing device 4 of the present invention is used as the developing means, and the rotating shaft of the photosensitive member 1 and the sleeve shaft 81 are arranged so that the distance between the surface of the photosensitive member 1 and the surface of the developing roller is a predetermined interval. A support plate 69 which is a support plate member for positioning and supporting the shaft, and a plurality of bearing members provided on the support plate 69 for rotatably supporting one end in the axial direction of the rotation shaft of the photoreceptor 1 and the sleeve shaft 81. The bearing member that supports at least the sleeve shaft 81 provided on the support plate 69 is a ball bearing 40, and the ball bearing 30 provided on the developing device main body and the ball bearing 40 provided on the support plate 69 are provided. It is arranged opposite to the same axis The elastic member such as an elastic tube or a compression coil spring has a different end from one end in contact with the side surface of the inner ring 31 of the ball bearing 30 and a side surface on the side in contact with the side surface of the inner ring 41 of the ball bearing 40. A contact member such as a gear 82 provided on the sleeve shaft 81 is in contact with the side surface of the inner ring 41 of the ball bearing 40 on the opposite side, and the elastic member moves the inner ring 41 of the ball bearing 40 toward the contact member. The inner ring 41 of the ball bearing 40 is held between the elastic member and the contact member by pressing in the axial direction. Thereby, since the inner ring 41 of the ball bearing 40 is held by the elastic member and the contact member provided on the sleeve shaft 81, the inner ring 41 can be rotated by the rotation of the sleeve shaft 81. Therefore, it is possible to prevent the inner ring 41 and the sleeve shaft 81 of the ball bearing 40 from spinning idle. Therefore, it is possible to prevent the inner ring 41 and the sleeve shaft 81 from rubbing due to sliding of the inner ring 41 of the ball bearing 40 and the sleeve shaft 81 due to the idle rotation of the inner ring 41 and the sleeve shaft 81. Can do.
Further, according to the present embodiment, the collar 67 which is a partition member is provided on the sleeve shaft 81 between the ball bearing 30 provided in the developing device main body and the ball bearing 40 provided in the support plate 69. The elastic tube and the compression coil spring are provided so as to sandwich the collar 67. Thereby, the compression rate of the elastic body tube or the compression coil spring can be easily increased, and the inner rings 31 and 41 of the ball bearings 30 and 40 can be pressed by the elastic body tube or the compression coil spring with a larger load. Further, by dividing the elastic tube into the elastic tube 66 and the elastic tube 68, the width of the elastic tubes 66, 68 can be set short, and the elastic tubes 66, 68 are hardly buckled and deformed. be able to.

1 is a schematic configuration diagram of one end portion of a developing device according to Embodiment 1. FIG. 1 is a schematic configuration diagram of a printer according to an embodiment. FIG. 3 is a schematic sectional view of an image forming unit. FIG. 3 is a schematic diagram of a developing roller. FIG. 3 is a perspective view of a developing device and a photoreceptor that are positioned and supported by a support plate. The schematic diagram at the time of arrange | positioning a slip prevention member between the end surface of a compression coil spring, and the side surface of the inner ring | wheel of a ball bearing. FIG. 6 is a schematic configuration diagram of one end portion of a developing device according to Embodiment 2. The schematic block diagram at the time of providing a slip prevention member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 4 Developing apparatus 30 Ball bearing 31 Inner ring 40 Ball bearing 41 Inner ring 51 Supply screw 52 Recovery screw 53 Circulating screw 57 Doctor blade 62 Case 66 Elastic body tube 67 Collar 68 Elastic body tube 69 Support plate 80 Compression coil spring 81 Sleeve shaft 82 Gear 83 Parallel pin 84 Stepped portion 90 Anti-slip member 411 Upper developing roller 412 Lower developing roller

Claims (11)

A developer carrier for carrying a developer for developing the latent image carried on the latent image carrier;
In a developing device comprising a ball bearing provided in a device main body that rotatably supports the rotation shaft of the developer carrier,
A developing device comprising: a holding means for pressing the side surface of the inner ring portion of the ball bearing that intersects the rotation axis direction so as to hold the inner ring portion so as to be rotatable integrally with the rotation shaft. The developing device according to claim 1.
The holding means includes an elastic member in contact with a side surface of the inner ring portion, and a step portion formed on the rotation shaft in contact with a side surface opposite to the side surface of the inner ring portion in contact with the elastic member. The inner ring portion is pressed between the stepped portion and the elastic member by pressing the inner ring portion toward the stepped portion in the direction of the axis of rotation by the restoring force of the elastic member provided to be compressed to A developing device. The developing device according to claim 2.
The developing device according to claim 1, wherein the elastic member is a cylindrical rubber member. The developing device according to claim 3.
A developing device comprising buckling deformation preventing means for preventing buckling deformation of the rubber member. The developing device according to claim 4.
The developing device according to claim 1, wherein the buckling deformation preventing means is a cover member that covers the rubber member in contact with the surface. The developing device according to claim 2.
The developing device according to claim 1, wherein the elastic member is a spring member. The developing device according to claim 6.
A developing device comprising an anti-slip member for preventing the end surface of the spring member and the side surface of the inner ring portion from slipping between the end surface of the spring member and the side surface of the inner ring portion. In an image forming apparatus comprising: a latent image carrier that carries a latent image; and a developing unit that develops the latent image carried on the latent image carrier.
An image forming apparatus using the developing device of claim 1, 2, 3, 4, 5, 6, or 7 as the developing means. The image forming apparatus according to claim 8.
A support plate member provided with a plurality of bearing members that rotatably support one axial end of each of the rotation shaft of the latent image carrier and the rotation shaft of the developer carrier;
The bearing member that supports at least the rotation shaft of the developer carrier provided on the support plate member is a ball bearing,
Image forming characterized in that second holding means for pressing the side surface of the inner ring portion of the ball bearing provided on the support plate member to hold the inner ring portion is provided on the rotation shaft of the developer carrier. apparatus. In an image forming apparatus comprising: a latent image carrier that carries a latent image; and a developing unit that develops the latent image carried on the latent image carrier.
The developing device of claim 2, 3, 4, 5, 6 or 7 is used as the developing means.
A support plate for positioning and supporting the rotation shaft of the latent image carrier and the rotation shaft of the developer carrier so that the distance between the surface of the latent image carrier and the surface of the developer carrier is a predetermined distance. Members,
A plurality of bearing members provided on the support plate member and rotatably supporting axial ends of the rotation shaft of the latent image carrier and the rotation shaft of the developer carrier;
The bearing member that supports at least the rotation shaft of the developer carrier provided on the support plate member is a ball bearing, and a ball bearing provided on the developing device body and a ball bearing provided on the support plate member Are arranged on the same axis and facing each other,
The elastic member is in contact with the side surface of the inner ring portion of the ball bearing provided on the support plate member at the other end different from one end contacting the side surface of the inner ring portion of the ball bearing provided on the developing device main body. A contact member provided on the rotating shaft is in contact with a side surface of an inner ring portion of a ball bearing provided on the support plate member on the side opposite to the side surface on which the contact is made;
The inner ring portion of the ball bearing provided on the support plate member corresponds to the elastic member by pressing the inner ring portion of the ball bearing provided on the support plate member in the axial direction toward the contact member. An image forming apparatus configured to be held by a contact member. The image forming apparatus according to claim 10.
A partition member is provided on the rotating shaft between a ball bearing provided in the developing device main body and a ball bearing provided in the support plate member;
An image forming apparatus, wherein the elastic member is divided and provided so as to sandwich the partition member.

Images