JP6488672B2 - Rotating bearing cooling structure, developing device, image forming apparatus, and rotating bearing structure - Google Patents

Description

  The present invention relates to a rotary shaft movement prevention structure, a developing device, an image forming apparatus, and a rotary bearing structure.

  An electrophotographic image forming apparatus may be used as an image forming apparatus that forms digitized information as an image on a recording medium. In an electrophotographic image forming apparatus, a developing device for developing an electrostatic latent image formed on a photoreceptor is provided.

  Conventionally, shafts of rotating members such as a developing device and a conveying screw in a developer conveying path are rotatably supported by bearings. In addition to receiving the rotation of the rotating member as a bearing, the bearing is required to have a function of preventing leakage of the developer. Therefore, a bearing incorporating a seal member is known. Some seal members are used by applying grease to the seal portion from the viewpoint of slidability, durability, and sealability, or some materials can be used without using grease.

  However, in any case, when the rotating member rotates, the developer that has reached the softening point is fixed by the frictional heat between the rotating member, the bearing, and the seal member, and this fixed developer flows into the apparatus, and finally Between the layer thickness regulating member and the developer carrying member, it may cause a white streak image or an increase in the torque of the apparatus due to the fixing of the developer on the bearing. In addition, depending on the material of the sealing member, the sealing performance may be lowered due to temperature rise.

  In order to solve such problems, in order to prevent the temperature of the seal member from rising, the shaft is provided with a communication groove, and the bearing is provided with a waste heat outlet for waste heat to accumulate heat in the closed space between the bearing and the seal member. The structure which suppresses the frictional heat to be performed is proposed (for example, refer patent document 1).

  In Patent Document 1, a communication groove is provided in the shaft, and a waste heat port for waste heat is provided in the bearing to suppress the temperature rise of the seal member due to the waste heat of friction heat. Propagates to the seal member and the temperature of the seal member rises. Since the communication groove becomes smaller with the shaft, bearing, and developer over time, it is assumed that the air permeability decreases and the temperature of the seal member affects the rise. Occurrence occurs not a little. Further, assuming that the toner has a low melting point, it is desired to further suppress the temperature rise of the bearing seal member.

  The temperature rise of the bearing is particularly a problem in the rotating member used in the developing device due to the above-described circumstances. However, the heat radiation of the bearing, in which the temperature rises due to friction, is a common problem in the apparatus including the rotating member, and is not limited to the developing device.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to more efficiently cool a bearing of a rotating member in an apparatus including the rotating member.

In order to solve the above-described problem, an aspect of the present invention is a rotary bearing cooling structure for cooling a bearing of a rotary member, the bearing supporting the shaft of the rotary member rotatably, and more than the bearing provided on the end side of the shaft, anda movement restricting member for restricting the movement in the axial direction of said rotary member, said movement restricting member, the air flow by rotating along with the rotation of said rotary member An airflow generating structure to be generated, wherein the airflow generated by the rotation of the movement restricting member is configured to pass through a space facing the bearing, and a portion of the shaft that is in contact with the bearing has a smaller diameter than other portions And the portion having a diameter smaller than that of the other portion in the shaft is made of a material having a higher thermal conductivity than the other portion .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform the cooling of the bearing of the rotation member in the apparatus containing a rotation member more efficiently.

1 is a diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the image creation part which concerns on embodiment of this invention. It is a figure which shows the detail of the stirring conveyance part periphery which concerns on embodiment of this invention. It is a figure which shows the structure of the retaining ring which concerns on embodiment of this invention. It is a figure which shows the airflow which generate | occur | produces with the retaining ring which concerns on embodiment of this invention. It is a figure which shows the bearing cooling structure which concerns on embodiment of this invention. It is a figure which shows the bearing cooling structure which concerns on embodiment of this invention. It is a figure which shows the bearing cooling structure which concerns on embodiment of this invention. It is a figure which shows the structure of the partition plate which concerns on embodiment of this invention. It is a figure which shows the airflow which generate | occur | produces with the retaining ring which concerns on embodiment of this invention. It is a figure which shows the bearing cooling structure and scattered toner suction structure which concern on embodiment of this invention. It is a figure which shows the structure of the retaining ring which concerns on embodiment of this invention. It is a figure which shows the airflow which generate | occur | produces with the retaining ring which concerns on embodiment of this invention. It is a figure which shows the bearing cooling structure which concerns on embodiment of this invention. It is a figure which shows the cooling effect of the bearing cooling structure which concerns on embodiment of this invention.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. Note that, in each drawing and each embodiment, the same member or a member having the same function is basically denoted by the same reference numeral, and redundant description is appropriately omitted.

  FIG. 1 is an overall configuration diagram showing a color copying machine as an image forming apparatus according to the present invention, and FIG. 2 is an enlarged view showing a configuration of an image forming unit thereof. As shown in FIG. 1, the toner container housing 31 disposed above the image forming apparatus main body 300 has four toner containers 32Y, 32M, 32C, and 32K corresponding to the respective colors (yellow, magenta, cyan, and black). Is installed detachably (changeable). Y, M, C, and K with numbers are subscripts indicating each color and are omitted as appropriate.

  An intermediate transfer unit 15 is disposed below the toner container housing 31. Image forming portions 6Y, 6M, 6C, and 6K for respective colors (yellow, magenta, cyan, and black) are arranged in parallel at a portion facing the intermediate transfer belt 8 as an intermediate transfer member provided in the intermediate transfer unit 15. As shown in FIG. 2, the image forming unit 6Y corresponding to yellow includes a drum-shaped photoconductor 1Y as a latent image carrier, a charging unit 4Y disposed around the photoconductor 1Y, and a developing device 5Y (development). Part), a cleaning part 2Y, a static elimination part shown in the figure, and the like. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photoreceptor 1Y, and a yellow image is formed on the photoreceptor 1Y.

  The other three image forming units 6M, 6C, and 6K have substantially the same configuration as that of the image forming unit 6Y corresponding to yellow except that the color of the toner used is different. A corresponding image is formed. Hereinafter, description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

  As shown in FIG. 2, the photoreceptor 1Y is rotated in the clockwise direction in FIG. 2 by a drive motor (not shown). Then, the surface of the photoreceptor 1Y is uniformly charged at the position of the charging unit 4Y (a charging process). Thereafter, the surface of the photoreceptor 1Y reaches the irradiation position of the laser beam L emitted from the exposure unit 7 (see FIG. 1), and an electrostatic latent image corresponding to yellow is formed by exposure scanning at this position. It is formed. This is the exposure process.

  Thereafter, the surface of the photoconductor 1Y reaches a position facing the developing device 5Y, and the electrostatic latent image is developed at this position to form a yellow toner image. This is the development process. Thereafter, the surface of the photoreceptor 1Y reaches a position facing the intermediate transfer belt 8 and the first transfer bias roller 9Y, and the toner image on the photoreceptor 1Y is transferred onto the intermediate transfer belt 8 at this position. This is the primary transfer process. At this time, a small amount of untransferred toner remains on the photoreceptor 1Y.

  Thereafter, the surface of the photoreceptor 1Y reaches a position facing the cleaning unit 2Y, and untransferred toner remaining on the photoreceptor 1Y at this position is mechanically collected by the cleaning blade 2a. This is the cleaning process. Finally, the surface of the photoconductor 1Y reaches a position facing a neutralization unit (not shown), and the residual potential on the photoconductor 1Y is removed at this position. Thus, a series of image forming processes performed on the photoreceptor 1Y is completed.

  The image forming process described above is performed in the other image forming units 6M, 6C, and 6K similarly to the yellow image forming unit 6Y. That is, a laser beam L based on image information is emitted from the exposure unit 7 disposed below the image forming unit onto the photoreceptors 1M, 1C, and 1K of the image forming units 6M, 6C, and 6K. The Specifically, the exposure unit 7 emits laser light L from a light source and irradiates the latent image carrier through a plurality of optical elements while scanning the laser light L with a polygon mirror that is rotationally driven.

  Thereafter, the toner images of the respective colors formed on the respective photoconductors through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8. Here, referring to FIG. 1, the intermediate transfer unit 15 includes an intermediate transfer belt 8, four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a secondary transfer backup roller 12, a cleaning backup roller 13, and a tension roller. 14 and the intermediate transfer cleaning unit 10. The intermediate transfer belt 8 is stretched and supported by the three rollers 12 to 14 and is endlessly moved in the direction of the arrow in FIG.

  The four primary transfer bias rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photoreceptors 1Y, 1M, 1C, and 1K to form a primary transfer nip. Then, a transfer bias reverse to the polarity of the toner is applied to the primary transfer bias rollers 9Y, 9M, 9C, and 9K. The intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photoreceptors 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  The intermediate transfer belt 8 on which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19. At this position, the secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 8 are transferred onto a transfer material P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, the untransferred toner that has not been transferred to the transfer material P remains on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, the untransferred toner on the intermediate transfer belt 8 is collected. Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

  Here, the transfer material P transported to the position of the secondary transfer nip is transported from the paper feed unit 26 disposed below the apparatus main body 300 via the paper feed roller 27, the registration roller pair 28, and the like. It has been done. Specifically, a plurality of transfer materials P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is rotated in the counterclockwise direction in FIG. 1, the uppermost transfer material P is fed between the rollers of the registration roller pair 28. The transfer material P conveyed to the registration roller pair 28 is temporarily stopped at the position of the roller nip of the registration roller pair 28 that has stopped rotating. Then, the registration roller pair 28 is rotationally driven in synchronization with the color image on the intermediate transfer belt 8, and the transfer material P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the transfer material P.

  Thereafter, the transfer material P on which the color image has been transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the transfer material P by heat and pressure generated by the fixing roller and the pressure roller. Thereafter, the transfer material P is discharged out of the apparatus through the rollers of the discharge roller pair 29. The transferred P discharged from the apparatus by the discharge roller pair 29 is sequentially stacked on the stack unit 30 as an output image. Thus, a series of image forming processes in the image forming apparatus is completed.

Next, the configuration and operation of the developing device in the image forming unit will be described in more detail with reference to FIG. The developing device Y is disposed in a developer carrier 51Y that faces the photoreceptor 1Y, a layer thickness regulating member 52Y that faces the developer carrier 51Y, a first agitation conveyance path 53Y, and a second agitation conveyance path 54Y. The two agitating / conveying members 55Ya and 55Yb, the density detecting sensor 56Y for detecting the toner density in the developer, and the like are arranged in the casing 57Y.

  The developer carrier 51Y includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. A two-component developer G composed of a carrier and toner is accommodated in the agitation transport paths 53Y and 54Y. The agitating / conveying path 54Y communicates with the toner receiving port 43Y through an opening formed thereabove.

  The developing device 5Y configured as described above operates as follows. The sleeve of the developer carrier 51Y rotates in the direction of the arrow in FIG. The developer G carried on the developer carrier 51Y by the magnetic field formed by the magnet moves on the developer carrier 51Y as the sleeve rotates. Here, the developer G in the developing device 5Y is adjusted so that the ratio of toner in the developer (toner concentration) is within a predetermined range. Specifically, according to the consumption of toner in the developing device 5Y, the toner stored in the toner container 32Y is replenished into the second agitating / conveying path 54Y via a toner replenishing device (not shown).

  Thereafter, the toner replenished in the second agitating / conveying path 54Y is mixed and agitated with the developer G by the first agitating / conveying member 55Ya and the second agitating / conveying member 55Yb. It is conveyed in a direction corresponding to the direction, and circulates through the first agitation conveyance path 53Y and the second agitation conveyance path 54Y (movement in the direction perpendicular to the paper surface of FIG. 2). That is, the first agitation transport member 55Ya and the second agitation transport member 55Yb function as transport rollers that transport the developer in the main scanning direction. The toner in the developer G is adsorbed to the carrier by frictional charging with the carrier and is carried on the developer carrier 51Y together with the carrier by the magnetic force formed on the developer carrier 51Y.

  The developer G carried on the developer carrier 51Y is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the layer thickness regulating member 52Y. The developer G on the developer carrying member 51Y is conveyed to a position (development region) facing the photoreceptor 1Y after the developer amount is made appropriate at this position. The toner is attracted to the latent image formed on the photoreceptor 1Y by the electric field formed in the development area. Thereafter, the developer G remaining on the developer carrier 51Y reaches the upper portion of the developer container 53Y as the sleeve rotates, and is detached from the developer carrier 51Y at this position.

  Next, first stirring and conveying members 55Ya, 55Ma, 55Ca, and 55Ka that are rotation members included in the developing devices 5Y, 5M, 5C, and 5K according to the present embodiment, and second agitating and conveying members 55Yb, 55Mb, and 55Cb, respectively. The 55Kb bearing cooling structure will be described. This bearing cooling structure is the rotary bearing cooling structure according to the present embodiment. Since the bearing cooling structure in each agitating and conveying member of each color has the same form, the rotating member will be simply described as the agitating and conveying member 55 below.

(First embodiment)
As shown in FIG. 3, the stirring and conveying member 55 includes a shaft portion 55A and a conveying screw 55B provided on the outer peripheral surface of the shaft portion 55A. The agitating / conveying member 55 is rotatably supported at both ends 55Aa and 55Ab of the shaft portion 55A by bearings 60 and 60 fitted in a casing 57 containing developer.

  The bearings 60, 60 are sliding bearings made of resin (for example, polyoxymethylene), and rotatably support the shaft portion 55A with shaft support portions 61, 61. The bearings 60, 60 according to the present embodiment include seal members 62, 62 that contact the shaft portion 55 </ b> A inside the casing with respect to the shaft support portions 61, 61. In this embodiment, the bearings 60 and 60 and the seal member 62 constitute a bearing seal structure.

  The stirring and conveying member 55 according to the present embodiment is provided with a retaining ring 100 for restricting axial movement outside the bearing seal structure. That is, the retaining ring 100 functions as a movement restricting member that restricts the movement of the stirring and conveying member 55 in the axial direction. The outside of the bearing seal structure is the opposite side of the portion of the shaft portion 55A supported by the bearing 60 to the portion where the conveying screw 55B is provided, and corresponds to the end portion side of the shaft portion 55A. . The retaining ring 100 is a ring-shaped member fixed to the shaft portion 55A. The axial movement of the agitating and conveying member 55 is regulated by contacting the casing 57 in the axial direction of the shaft portion 55A.

  4A and 4B are views showing details of the retaining ring 100 according to the present embodiment. FIG. 4A is a diagram illustrating a state viewed from the axial direction in a state where the retaining ring 100 is fixed to the shaft portion 55A. FIG. 4B is a cross-sectional view taken along the cutting line AA ′ shown in FIG.

  As shown in FIG. 4A, the retaining ring 100 includes a base portion 101, an outer ring portion 102, and a wing portion 103. The base portion 101 is a central portion that becomes a base of the retaining ring 100 and is a portion that is fixed to the shaft portion 55 </ b> A of the stirring and conveying member 55. A through hole 104 for passing the retaining ring 100 through the shaft portion 55 </ b> A is provided in the base portion 101.

  As shown in FIG. 4A, the through-hole 104 is a D-cut through hole. A portion of the shaft portion 55A where the retaining ring 100 is fixed is provided with a notch corresponding to the D-cut shape of the through hole 104. When the through hole 104 fits into the notch of the shaft portion 55A, the retaining ring 100 rotates simultaneously with the rotation of the shaft portion 55A.

  Further, as shown in FIG. 4B, a retaining portion 105 is provided inside the through hole 104. The retaining portion 105 is a convex portion protruding from the inner wall of the through hole 104. A concave portion corresponding to the convex portion of the retaining portion 105 is provided in a portion where the retaining ring 100 is fixed in the shaft portion 55A.

  By fitting the convex portion of the retaining portion 105 provided in the through hole 104 into the concave portion of the shaft portion 55A, the position of the retaining ring 100 with respect to the shaft portion 55A is fixed. As a result, even if a force is applied in a direction in which the retaining ring 100 comes into contact with the casing 57 and changes the positional relationship with the shaft portion 55A, the position of the retaining ring 100 does not move and the retaining ring 100 is moved relative to the shaft portion 55A. The state where 100 is fixed is maintained.

  The base 101 and the outer ring portion 102 are connected via a wing portion 103. The wing portion 103 has a fin shape, and the snap ring 100 rotates according to the rotation of the shaft portion 55A to generate an air flow. That is, the wing 103 functions as an airflow generation structure. FIG. 5 is a diagram showing the airflow generated by the rotation of the retaining ring 100 by broken arrows. As shown in FIG. 5, when the retaining ring 100 rotates, an air flow from the inside to the outside of the retaining ring 100 is generated.

  Here, the outer side of the retaining ring 100 is the opposite side of the bearing seal structure across the retaining ring 100 in the axial direction of the shaft portion 55A, and the inner side is the bearing seal structure side. As shown in FIG. 5, the diameter of the outer ring portion 102 of the retaining ring 100 is provided outside the shaft support portion 61 in the normal direction of the side surface of the shaft portion 55 </ b> A. With such a structure, an airflow from the space facing the shaft support portion 61 toward the outside of the retaining ring 100 is generated by the rotation of the retaining ring 100, and the bearing 60 is cooled by the airflow.

  The retaining ring 100 is made of a metal having a high thermal conductivity such as aluminum or copper. Thereby, the heat dissipation effect from the retaining ring 100 itself can be enhanced by the airflow generated as shown in FIG. As a result, the heat generated by the friction between the shaft support portion 61 and the shaft portion 55A is also radiated from the retaining ring 100 via the shaft portion 55A, and the cooling effect of the bearing seal structure can be enhanced.

  Similarly, the bearing 60 itself including the shaft support portion 61 can be made of the above-described metal having high thermal conductivity, so that the heat radiation effect due to the airflow generated by the rotation of the retaining ring can be further enhanced. In addition, when the material of the shaft support portion 61 is a metal, there is a possibility that abnormal noise or wear may occur due to friction with the shaft portion 55A. For this reason, it is preferable to perform a treatment for improving the frictional property on the contact portion between the shaft support portion 61 and the shaft portion 55A.

  Examples of the treatment for improving the rubability include performing fluorine processing and locally adopting a material having a low coefficient of friction. An embodiment in which grease with high thermal conductivity is applied is also conceivable.

(Second Embodiment)
FIG. 6 is a view showing a bearing cooling structure according to the second embodiment. As shown in FIG. 6, the bearing cooling structure according to the second embodiment has substantially the same configuration as that of the first embodiment, but the outer ring portion 102 is extended inward in the axial direction of the shaft portion 55A. In other words, it enters the space between the outer periphery of the bearing 60 and the shaft support portion 61. An extended portion of the outer ring portion 102 that has entered the inside of the bearing 60 functions as a flow path forming portion.

  As a result, the outer ring portion 102 faces the normal direction of the shaft support portion 61 and the shaft portion 55 </ b> A in a space where the airflow generated by the rotation of the retaining ring 100 passes and faces the shaft support portion 61. That is, the shaft support portion 61 and the outer ring portion 102 face each other across a space through which an airflow for cooling the shaft support portion 61 to be cooled passes.

  In the case of the aspect shown in FIG. 5, the intake air generated by the rotation of the retaining ring 100 may affect the outside of the bearing 60. In contrast, due to the structure of the outer ring portion 102 as shown in FIG. 6, the intake air generated by the retaining ring 100 is more reliably performed from the space between the outer wall of the bearing 60 and the shaft support portion 61. The shaft support 61 can be cooled more reliably.

(Third embodiment)
FIG. 7 is a view showing a bearing cooling structure according to the third embodiment. As shown in FIG. 7, the bearing cooling structure according to the third embodiment is provided with a through hole 106 that is an opening that penetrates the bearing 60 and the casing 57. The through hole 106 is a path for the air flow generated by the retaining ring 100 and is provided further in the space from the retaining ring 100 to the shaft support portion 61. In other words, the through hole 106 faces a space generated by the rotation of the retaining ring 100 and is provided on the opposite side of the retaining ring 100 via the shaft support portion 61 to serve as an air flow path.

  As a result, a path of airflow is generated in the space from the retaining ring 100 to the through hole 106, and the airflow generated by the retaining ring 100 generates a negative pressure in the space facing the shaft support portion 61, and penetrates by the negative pressure. Inhalation is performed from the hole 106. Therefore, the flow of the airflow can be made smooth and the cooling effect of the shaft support portion 61 can be further enhanced.

(Fourth embodiment)
FIG. 8 is a view showing a bearing cooling structure according to the fourth embodiment. As shown in FIG. 8, in the bearing cooling structure according to the fourth embodiment, a through hole 106 is provided in the same manner as the structure according to the third embodiment. In the case of the structure shown in FIG. 7, since the airflow generated by the rotation of the retaining ring 100 generates intake air from the through hole 106, mainly the cooling effect of the lower shaft support portion 61 in the figure is enhanced. Become. As a result, the cooling effect of the upper shaft support portion 61 in the drawing may be lower than that of the lower shaft support portion 61.

  On the other hand, in the bearing cooling structure according to the present embodiment, as shown in FIG. 8, a partition plate 107 is provided inside the retaining ring 100 in the axial direction of the shaft portion 55A. FIG. 9 is a diagram illustrating a state in which the partition plate 107 is viewed from the plate surface. As shown in FIG. 9, the partition plate 107 is provided with a shaft hole 108 through which the shaft portion 55 </ b> A and the shaft support portion 61 pass, and a vent hole 109 through which an air flow generated by the retaining ring 100 passes.

  As shown in FIG. 8, the partition plate 107 is disposed so that the airflow generated by the retaining ring 100 passes through the space facing the bearing 60 and blocks the passage of the airflow that generates intake air from the through hole 106. In other words, the partition plate 107 divides the space facing the through hole 106 and the space facing the retaining ring 100 in the space facing the shaft support portion 61 that is a flow path of the air flow generated by the rotation of the retaining ring 100. Are arranged as follows.

  With such a configuration, the passage of the air current is limited to the vent 109 only. And the partition plate 107 is arrange | positioned so that the vent 109 may be located in the circumference | surroundings of 55 A of axial parts on the opposite side to the through-hole 106. FIG.

  FIG. 10 is a diagram illustrating a path of an air flow generated by the retaining ring 100 in the bearing cooling structure according to the fourth embodiment. As shown in FIG. 10, the airflow generated by the retaining ring 100 first generates a negative pressure in a portion of the shaft support portion 61 that is exposed to the outside of the partition plate 107.

  Then, the negative pressure generated outside the partition plate 107 passes through the vent 109 provided in the partition plate 107 and generates a negative pressure inside the partition plate 107. The negative pressure generated in the space inside the partition plate 107 passes through the space facing the shaft support portion 61 around the shaft portion 55A, and is sucked from the through hole 106 provided on the side opposite to the vent hole 109. Is generated.

  Thus, according to the bearing cooling structure according to the fourth embodiment, the airflow generated by the retaining ring 100 can guide the airflow so as to pass through the entire space facing the shaft support portion 61. The cooling effect of the support part 61 can be further enhanced.

  In the first to fourth embodiments, the case has been described as an example in which an airflow from the inside to the outside of the retaining ring 100 is generated in the axial direction of the shaft portion 55A. However, this is only an example, and even when an air flow from the outside to the inside of the retaining ring 100 is generated, an air flow that flows in the space facing the bearing 60 and the shaft support portion 61 is generated, so that the same as above. An effect can be obtained.

(Embodiment 5)
FIG. 11A is a diagram illustrating a bearing cooling structure and a scattered toner suction structure according to the fifth embodiment. As shown in FIG. 11A, the bearing cooling structure according to the fifth embodiment is based on the structure according to the fourth embodiment, and the through hole 106 is connected to the scattered toner suction port 110 as a space. .

  FIG. 11B is a diagram illustrating a configuration of the image forming unit according to the present embodiment, and corresponds to FIG. As shown in FIG. 11B, in the image forming unit according to this embodiment, the scattered toner suction port 110 is located in the casing 57Y in the vicinity of the developer carrier 51Y and at the downstream side in the rotation direction. Is provided. The scattered toner suction port 110 functions as an exhaust port that connects the space inside the developing device and the outside space.

  With such a configuration, the intake air generated in the through hole 106 due to the rotation of the retaining ring 100 generates an air flow from the inside of the casing 57 toward the through hole 106 via the scattered toner suction port 110. As a result, the scattered toner scattered inside the casing 57Y is sucked into the through hole 106 through the scattered toner suction port 110.

  With such a configuration, it is possible to discharge the scattered toner inside the stirring and conveying path 53Y in the casing 57Y. The toner sucked into the through hole 106 adheres to the filter 111 provided outside the retaining ring 100 in the axial direction of the shaft portion 55A. This prevents the scattered toner from diffusing inside the apparatus.

  As the filter 111, various filters can be used as long as the filter 111 has an opening that allows air to pass and does not allow toner to pass. The position where the filter 111 is provided is not limited to the outside of the retaining ring 100 shown in FIG. 11A, but may be the position of the through hole 106 or the position of the scattered toner suction port 110, for example.

  The seal member 62 is a seal that is in contact with the shaft portion 55A. In the state of being in contact with the shaft portion 55A, the intrusion of powder from the outside to the inside of the casing 57Y or the axial direction from the inside to the outside. Regulates leakage of powder into the body.

  Here, the contact portion between the seal member 62 and the shaft portion 55A needs to be used by applying grease to the seal portion from the viewpoint of slidability, durability, and sealing performance. However, when applying grease, the grease is inevitably applied in the vicinity of the developer. As a result, there is a possibility that the grease may enter the developer accommodating portion inside the seal member 62 due to the production assembly process or the operation of the conveying screw during machine operation.

  When the grease enters the inside, agglomerates of the developer and the grease are generated, and there is a problem that image quality deterioration such as white streaks occurs due to the agglomerates affecting the development. In addition, it is desired to reduce grease from the viewpoint of simplification of production process and cost reduction.

  On the other hand, an ALP slide seal that does not use grease may be used, thereby solving the above-described problems. However, the sealing performance of this ALP slide seal has temperature dependence, and the sealing performance decreases as the temperature of the seal increases. Therefore, the required sealing performance cannot be ensured depending on the use conditions.

  By using the bearing cooling structure according to the present invention, the cooling performance of the bearing 60 and the seal member 62 can be enhanced. Therefore, when the ALP slide seal is used, the deterioration of the seal performance can be suppressed, and the bearing life can be extended. I can do it.

(Embodiment 6)
In the third, fourth, and fifth embodiments, the case where the air passage is provided by providing the through hole 106 has been described as an example. However, the provision of the through hole 106 increases one design constraint. Moreover, it may be difficult to provide the through hole 106 in relation to the shape for other functions. In this embodiment, an example will be described in which a passage for airflow is secured without providing the through hole 106.

  FIGS. 12A and 12B are views showing details of the retaining ring 100 according to the sixth embodiment. FIG. 12A is a diagram showing a state viewed from the axial direction in a state where the retaining ring 100 is fixed to the shaft portion 55A. FIG. 4B is a cross-sectional view taken along the cutting line AA ′ shown in FIG.

  As shown in FIGS. 12A and 12B, the retaining ring 100 according to the present embodiment has a structure that is substantially the same as the structure described in FIG. 4, but a portion in which a wing 103 around the base 101 is formed. Is divided into an inner side and an outer side, and an inner wing portion 103a is formed on the inner side and an outer wing portion 103b is formed on the outer side. The inner wing portion 103a and the outer wing portion 103b each have a fin shape, and the snap ring 100 rotates according to the rotation of the shaft portion 55A to generate an air flow.

  Here, the inner wing 103a and the outer wing 103b generate airflow in different directions. In the present embodiment, the inner wing portion 103a and the outer wing portion 103b are configured to generate airflows in opposite directions. In the retaining ring 100 according to the present embodiment, the outer wing portion 103b generates an airflow from the right side to the left side of the retaining ring 100 in FIG. 12B, and the inner wing portion 103a is the retaining ring in FIG. 12B. An air flow from the left side of 100 toward the right side is generated.

  FIG. 13 is a diagram illustrating an air flow generated by the retaining ring 100 according to the present embodiment. As shown in FIG. 13, when the retaining ring 100 according to the present embodiment rotates, an air flow from the outer side to the inner side of the retaining ring 100 is generated by the inner wing portion 103 a in a portion closer to the inner side of the diameter of the retaining ring 100. To do. In other words, the air flow generated by the inner wing portion 103a is an air flow in a direction from the retaining ring 100, which is a movement restricting member, toward the space facing the bearing 60.

  Further, in the portion closer to the outer side of the diameter of the retaining ring 100, an air flow from the inner side to the outer side of the retaining ring 100 is generated by the outer wing portion 103b. In other words, the air flow generated by the outer wing portion 103 b is an air flow in a direction from the space facing the bearing 60 toward the retaining ring 100.

  As a result, airflow is supplied to the space facing the shaft support portion 61, and the supplied airflow is sucked out of the retaining ring 100 by the retaining ring 100. Thus, according to the retaining ring 100 according to the present embodiment, it is possible to secure a flow path of the air flow generated by the retaining ring 100 without providing the through hole 106 as shown in FIG.

(Embodiment 7)
In the present embodiment, an aspect in which the heat generation in the bearing 60 and the seal member 62 is reduced and the cooling performance is further improved will be described. FIG. 14 is a cross-sectional view showing the periphery of the bearing 60 according to the seventh embodiment. As shown in FIG. 14, the shaft portion 55 </ b> A according to this embodiment is rotatably supported by a bearing 60 and sealed by a seal member 62 as in the other embodiments described above. Here, the end portion 55Aa, which is the end portion of the shaft portion 55A according to the present embodiment, is formed to be narrower than the portion where the conveying screw 55B is provided.

  Heat generation of the bearing 60 and the seal member 62 is generated by friction with the rotating shaft portion 55A. The thermal energy generated at that time increases in accordance with the friction energy with the bearing 60 and the seal member 62. The friction energy between the bearing 60, the seal member 62, and the shaft portion 55A increases according to the area of the friction surface and the sliding speed of the friction surface. Therefore, as shown in FIG. 14, the diameter of the end portion 55Aa where the shaft portion 55A contacts the bearing 60 and the seal member 62 is reduced, and the contact area between the bearing 60 and the seal member 62 is reduced, thereby reducing the bearing 60. Heat generation due to friction between the seal member 62 and the shaft portion 55A can be suppressed.

  Further, as shown in FIG. 14, in the developing device 5 according to the present embodiment, in addition to the retaining ring 100 a fixed to the shaft portion 55 </ b> A on the outside of the casing 57, the inside of the casing 57 sealed by the seal member 62. Also, a retaining ring 100b which is a heat radiating plate is provided. For example, when a heat source such as a motor is disposed in the vicinity of the retaining ring 100a attached to the outside of the casing 57, the temperature of the air around the retaining ring 100a increases, and the cooling effect decreases.

  On the other hand, as shown in FIG. 14, when the retaining ring 100b is also provided inside the casing 57, the conveyed developer contacts the retaining ring 100b to release heat. Since the individual developer has a higher thermal conductivity than the gaseous air, it is possible to dissipate heat efficiently by disposing the retaining ring 100 in the space where the developer contacts and dissipating heat. It becomes.

  FIG. 15 shows the case where the retaining rings 100a and 100b are attached and the temperature when the diameter of the end portion 5Aa is the same as that of the shaft portion 55A and the retaining rings 100a and 100b are attached or the diameter of the end portion 55Aa is not attached. It is the graph which showed the change in cooling efficiency by showing the temperature at the time of thinning as a percentage. In FIG. 15, the state where the retaining rings 100a and 100b are not attached is indicated by a solid line, the state where the retaining rings 100a are attached is indicated by a broken line, and the state where the retaining rings 100b are attached is indicated by a one-dot chain line.

  As shown in FIG. 15, the cooling efficiency is improved in the order of a solid line, a broken line, and a one-dot chain line. Moreover, in any state, the cooling efficiency is improved as the diameter of the end portion 55Aa is reduced. In this way, heat generation is suppressed by reducing the diameter of the end portion 55Aa supported by the bearing 60 and the seal member 62 in the shaft portion 55A and reducing the area of the portion where friction is generated by the rotation of the shaft portion 55A. I can do it. Further, by providing the retaining ring 100b inside the casing 57 sealed by the seal member 62 and performing heat radiation with the developer conveyed, the heat radiation effect can be enhanced.

  FIG. 14 shows an example in which a retaining ring 100 a and a retaining ring 100 b are provided on both sides of the bearing 60 and the seal member 62. However, this is an example. As shown by the solid line in FIG. 15, the cooling effect can be enhanced by making the diameter of the end portion 55Aa of the shaft portion 55A smaller than the position where the conveying screw 55B is provided, and the retaining rings 100a, 100b. Need not be provided.

  Further, only the retaining ring 100b may be provided without providing the retaining ring 100a. In particular, when a heat source is disposed in the vicinity of the retaining ring 100a and the temperature of the surrounding air is high, the cooling efficiency by the retaining ring 100a is low, resulting in a useless configuration. In such a case, it is preferable to provide only the retaining ring 100b.

  Moreover, in the said embodiment, the case where the components containing the structure for generating the airflow as shown in FIG. 4 etc. as a retaining ring 100b as a retaining ring 100b is provided as an example. However, this is an example. Since the retaining ring 100b mainly has a cooling effect by the conveyed developer rather than a cooling effect by the airflow, it may be a structure that functions as a heat sink rather than a structure for generating the airflow.

  Moreover, in the said embodiment, the case where the diameter of end part 55Aa, 55Ab of 55 A of axial parts is made narrower than the diameter of the part (henceforth "shaft main-body part") in which the conveyance screw 55B is provided is an example. As explained. As one aspect of this, the portion of the end portion 55Aa having a small diameter may be made of a material different from that of the shaft main body portion.

  Heat generated by friction between the bearing 60 and the seal member 62 and the end portion 55Aa is radiated through the retaining ring 100a and the retaining ring 100b. Therefore, the end 55Aa is preferably made of a material having as high a thermal conductivity as possible. Further, in FIG. 14, the retaining ring 100b is fixed to the shaft main body, but the portion 55Aa having a small diameter may be formed up to the portion where the retaining ring 100b is fixed.

  Moreover, in the said embodiment, as shown in FIG. 14, the case where the diameter of the whole end part 55Aa of a shaft main-body part is formed thin is taken as an example. However, this is an example, and the purpose is to reduce the friction area between the bearing 60 and the seal member 62. Accordingly, at least only the contact portion with the bearing 60 and the seal member 62 may be thinner than the other portions.

1 (Y, M, C, K) Image carrier 5 (Y, M, C, K) Developer 51 (Y, M, C, K) Developer carrier 53 (Y, M, C, K) Stirring Conveying path 55 (Ya, Yb) Rotating member 55A Shaft portion 55Aa, 55Ab End portion 57 Casing 61 Shaft support portion 60 Bearing 62 Seal member 100, 100a, 100b Retaining ring 101 Base portion
102 Outer ring portion 103 Wing portion 103a Inner wing portion 103b Outer wing portion 104 Through hole 105 Retaining portion 106 Through hole 107 Partition plate 108 Shaft hole 109 Vent hole 110 Scatter toner suction port 111 Filter G Developer

JP 2011-257703 A

Claims (17)

A rotary bearing cooling structure for cooling a bearing of a rotary member,
A bearing that rotatably supports the shaft of the rotating member;
Wherein provided on the end side of the shaft than the bearing includes a movement restricting member for restricting the movement in the axial direction of said rotary member,
The movement restricting member has an air flow generating structure that generates an air flow by rotating with the rotation of the rotating member, so that the air flow generated by the rotation of the movement restricting member passes through the space facing the bearing. Configured ,
The portion of the shaft that contacts the bearing has a smaller diameter than the other portions,
In the shaft, the portion having a smaller diameter than the other portion is made of a material having higher thermal conductivity than the other portion.
A rotating bearing cooling structure characterized by that.   The rotary bearing cooling structure according to claim 1, wherein a material of the movement restricting member is a metal.   The rotating bearing cooling structure according to claim 1 or 2, wherein a material of a portion of the bearing that supports the rotating member is a metal.   The rotating bearing cooling structure according to claim 3, wherein a portion of the bearing that supports the rotating member is subjected to a treatment for improving friction.   In the space facing the bearing through which the air flow generated by rotation passes, the movement restricting member faces the portion of the bearing that supports the rotating member in the normal direction of the shaft, thereby allowing the flow path of the air flow. The rotary bearing cooling structure according to any one of claims 1 to 4, further comprising a flow path forming portion to be formed. The movement restricting member has an air flow generating structure that generates air flows in different directions depending on the position of the axis in the normal direction,
The airflow generated by the rotation of the movement restriction member is an airflow in a direction from the movement restriction member toward the space facing the bearing, and an airflow in a direction from the space facing the bearing toward the movement restriction member. The rotating bearing cooling structure according to claim 1, wherein the rotating bearing cooling structure is a rotating bearing cooling structure. A developing device for developing an electrostatic latent image formed on a photoreceptor,
A developing device comprising the rotary bearing cooling structure according to any one of claims 1 to 6 in a bearing portion of a conveying roller that conveys the developer in a main scanning direction. A developing device for developing an electrostatic latent image formed on a photoreceptor,
Rotating bearing cooling structure on the bearing portion of the conveying roller for conveying the developer,
A developer carrier for supplying a developer to the photoreceptor;
An exhaust port connecting a space inside the developing device provided with the developer carrying member and the outside of the developing device;
With
The rotary bearing cooling structure is
A bearing that rotatably supports the shaft of the rotating member;
It is provided on the end side of the shaft with respect to the bearing, and restricts the movement of the rotating member in the axial direction.
A movement restricting member,
The movement restricting member has an air flow generating structure that generates an air flow by rotating with the rotation of the rotating member, so that the air flow generated by the rotation of the movement restricting member passes through the space facing the bearing. Configured,
The bearing faces a space facing the bearing through which an air flow generated by the rotation of the movement restricting member passes, and is provided on the opposite side of the movement restricting member via a portion of the bearing that supports the rotating member. Including an opening serving as a flow path for the airflow,
The opening is connected to the exhaust port;
A developing device. A partition that partitions the space facing the opening and the space facing the movement restricting member in the space facing the bearing through which the airflow generated by the rotation of the movement restricting member passes;
The partition includes a vent that connects a space that the opening faces and a space that the movement restricting member faces,
The developing device according to claim 8 , wherein the vent is provided on a side opposite to the side where the opening is provided around the shaft. A developing device for developing an electrostatic latent image formed on a photoreceptor,
A rotation bearing cooling structure for cooling a bearing portion of a conveyance roller that conveys the developer in the main scanning direction;
The rotary bearing cooling structure is
A bearing that rotatably supports the shaft of the transport roller;
A movement restriction member provided on a space side where the developer is conveyed from the bearing, and restricting movement of the conveyance roller in the axial direction;
The developing device according to claim 1, wherein the movement restricting member has a heat dissipation effect. Image forming apparatus characterized by including a developing device according to any one of claims 7 to 10. A rotating member that rotates according to power;
A bearing that rotatably supports the shaft of the rotating member,
The portion of the shaft of the rotating member that contacts the bearing has a smaller diameter than the other portions,
In the shaft, the portion having a smaller diameter than the other portion is made of a material having higher thermal conductivity than the other portion.
A rotary bearing structure characterized by that. A rotating member that rotates according to power;
The rotating member is provided with a screw,
A bearing that rotatably supports the shaft of the rotating member,
The portion in contact with the bearing in the shaft of the rotating member has a smaller diameter than the portion where the screw is provided,
In the shaft, the portion having a smaller diameter than the portion where the screw is provided is made of a material having a higher thermal conductivity than the other portion.
A rotary bearing structure characterized by that. In the bearing, the material of the portion that supports the rotating member is a metal.
The rotary bearing structure according to claim 12 or 13. The rotary bearing structure according to claim 14, wherein a treatment for improving friction is performed on a portion of the bearing that supports the rotary member. A developing device for developing an electrostatic latent image formed on a photoreceptor,
15. A developing device comprising the rotary bearing structure according to claim 13 or 14 in a bearing portion of a conveying roller for conveying a developer. An image forming apparatus comprising the developing device according to claim 13.