JP4793557B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus in which a main body holds a rotating body such as an image carrier or a developing roller.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic copying machine or a printer, a drum driving shaft that is pivotally supported by a side plate of the apparatus main body and rotationally driven by a chain sprocket 8 is fitted to an end of an image carrier drum. The image bearing drum is positioned by fitting the drive bearing provided on the fixed resin flange, and the drive transmission held on the drum drive shaft is engaged with the drive transmission received on the resin flange. There is a structure in which the image carrier drum is rotated by combining (Patent Document 1).

As another structure, a drum drive gear, which is a helical gear provided in the main body, is fitted to a drum gear, which is a helical gear fixed to one end of the image carrier drum, and rotates the image carrier drum. There is a structure (Patent Document 2).
JP-A-62-65049 JP-A-63-4252

  However, in the above prior art, since the shaft of the image carrier drum is composed of separate members at both ends, the degree of coaxiality between the shafts is reduced, the shaft shake increases, and the positional accuracy of the image carrier drum is lowered. Resulting in. In particular, in the case of a tandem type color printer or the like in which a plurality of image carrier drums are arranged, a desired color cannot be obtained unless toners of respective colors are overlapped with an accuracy of several tens of micrometers. This is a major factor that decreases the accuracy.

  Also, when the image carrier drum is driven by a gear, the larger the gear, the greater the number of gear teeth, the higher the accuracy, the less the rotation unevenness, and the higher the quality. However, when the image carrier drum has a gear, if the outer shape of the gear is larger than the outer shape of the process cartridge, the gear is caught on the intermediate transfer member or the like of the image forming apparatus when the process cartridge is replaced, making it difficult to attach and detach.

  The present invention solves the above-described problems, and provides an image forming apparatus having a structure in which the shaft accuracy is improved by eliminating the shaft shake of the rotating body, and the outer shape of the rotating body driving means can be increased to reduce the rotational unevenness and improve the accuracy. For the purpose.

In order to solve the above problems, an image forming apparatus of the present invention supports a first shaft holding member that supports one end of both ends of a shaft that penetrates and supports an image carrier, and supports the other end of the shaft. A second shaft holding member, a rotating body driving unit having a through hole through which the shaft passes and having a rotating body driving means for driving the image carrier; and the rotating body driving means for holding the first shaft A rotating body driving means holding portion that holds the rotating body driving means so as to be movable in a direction other than the axial direction of the shaft. To do.

Further, the rotating body driving means is a gear, and a moving distance in which the gear moves in a direction perpendicular to the axial direction out of directions other than the axial direction is shorter than a tooth height of the gear. And

Further, the rotating body driving means has a larger portion than the image carrier when projected from the insertion direction of the image carrier .

  The shaft is non-rotating.

Further, the rotary body drive means is characterized in that slidable in the axial direction.

Furthermore, the image forming apparatus of the present invention includes a first shaft holding member that supports one end of both ends of a shaft that penetrates and supports the image carrier, and a second shaft holding member that supports the other end of the shaft. A rotating body driving unit having a rotating body driving unit for driving the image carrier, and a rotating body driving unit holding member for holding the rotating body driving unit, wherein the rotating body driving unit is concentric with the shaft. The rotary body drive means having a groove, a holder held by the rotary body drive means holding member, and the image carrier and the rotary body drive means are connected in the holder and slidable in the axial direction. It has a coupling and an elastic member which enables the coupling to slide, and at least a part of the coupling is movable into the groove of the rotating body driving means.

Further, the image bearing member is characterized Rukoto pressed against the image bearing member inserting direction front side by the pressing mechanism.

Further, the image forming apparatus includes a plurality of the image carrier and the rotating body driving unit.

In addition, the penetrating and supporting shaft may be a shaft for penetrating and supporting a developing roller or a charging roller instead of the image carrier.

  According to the present invention, since the shaft of the rotating body can be a through-shaft, the shaft blur is reduced, the positional accuracy is improved, and the outer shape of the rotating body driving means can be increased, so that the rotation unevenness is reduced and the quality is improved. Further, it is possible to prevent the rotating body driving means from falling off and to prevent the gear from being disengaged. Further, when the shaft is non-rotating, the rotation of the rotating body can be rotated with high accuracy because no shake corresponding to the straightness occurs. In addition, since the slidable member is provided in the rotator driving unit, it is easy to match and connect the phases of the rotator and the rotator driving means, and the rotator unit can be set smoothly. Furthermore, since at least a part of the coupling can move inside the groove of the rotating body driving means, the axial space can be shortened. Moreover, since the rotating body unit has a pressurizing mechanism that presses the rotating body toward the front side in the inserting direction of the rotating body unit, the rotating body can be displaced in one direction. Furthermore, since a plurality of rotating body units and rotating body drive units are provided and the rotating body unit is held by the shaft holding member, the number of parts is reduced and the position accuracy is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an overall configuration of an embodiment of an image forming apparatus of the present invention, and FIG. 2 is an enlarged view of a transfer belt unit and an image forming unit of FIG. In the following description, the same components may be denoted by the same reference numerals in the drawings, and description thereof may be omitted. In this embodiment, an intermediate transfer belt is used as the transfer belt.

  In FIG. 1, an image forming apparatus 1 according to the present embodiment includes a housing main body 2 as an example of a main body, a first opening / closing member 3 that is detachably mounted on the front surface of the housing main body 2, and an upper surface of the housing main body 2. And a second opening / closing member (also serving as a paper discharge tray) 4 that can be freely opened and closed. Further, the first opening / closing member 3 is attached to the front surface of the housing body 2 so as to be freely opened and closed. An opening / closing lid 3 ′ is provided, and the opening / closing lid 3 ′ can be opened / closed in conjunction with or independently of the first opening / closing member 3.

  In the housing body 2, an electrical component box 5 incorporating a power circuit board and a control circuit board, an image forming unit 6, a blower fan 7, a transfer belt unit 9, and a paper feed unit 10 are disposed, and a first opening / closing member In FIG. 3, a secondary transfer unit 11, a fixing unit 12, and a recording medium conveying means 13 are arranged. The consumables in the image forming unit 6 and the paper feeding unit 10 are configured to be detachable from the main body. In this case, the configuration including the transfer belt unit 9 can be removed and repaired or replaced. It has become.

  The transfer belt unit 9 is disposed below the housing body 2 and is driven to rotate by a drive source (not shown), a driven roller 15 disposed obliquely above the drive roller 14, and the two rollers. 14, an intermediate transfer belt 16 that is stretched between 14 and 15 and is driven to circulate in the direction of the arrow in the figure, and a cleaning means 17 that contacts the surface of the intermediate transfer belt 16, and the driven roller 15 and the intermediate transfer belt 16 are The drive roller 14 is disposed in a direction inclined to the left in the drawing. As a result, the belt surface 16a with the belt conveyance direction downward when the intermediate transfer belt 16 is driven is positioned below. In the present embodiment, the belt surface 16a is a belt tension surface (surface pulled by the drive roller 14) when the belt is driven.

  The driving roller 14 and the driven roller 15 are rotatably supported by a support frame 9a, and a rotating portion 9b is formed at the lower end of the supporting frame 9a. The rotating portion 9b is a rotation provided on the housing body 2. The support frame 9a is fitted to the housing body 2 so as to be rotatable. A lock lever 9c is rotatably provided at the upper end of the support frame 9a, and the lock lever 9c can be locked to a locking shaft 2c provided in the housing body 2.

The drive roller 14 also serves as a backup roller for the secondary transfer roller 19 constituting the secondary transfer unit 11. As shown in FIG. 2, a rubber layer 14a having a thickness of about 3 mm and a volume resistivity of 10 ⁵ Ω · cm or less is formed on the peripheral surface of the drive roller 14 and is grounded through a metal shaft. Thus, a conductive path for the secondary transfer bias supplied via the secondary transfer roller 19 is formed. By providing the rubber layer 14a having high friction and shock absorption on the driving roller 14 in this way, the impact when the recording medium enters the secondary transfer portion is difficult to be transmitted to the intermediate transfer belt 16, and the image quality is deteriorated. Can be prevented.

  In the present embodiment, the diameter of the driving roller 14 is smaller than the diameter of the driven roller 15. Thereby, the recording medium after the secondary transfer can be easily peeled by the elastic force of the recording medium itself. The driven roller 15 is also used as a backup roller for the cleaning means 17. The cleaning means 17 is provided on the belt surface 16a side facing down in the transport direction. As shown in FIG. 2, a cleaning blade 17a for removing toner remaining on the surface of the intermediate transfer belt 16 after the secondary transfer and a toner transport member 17b for transporting the collected toner are provided, and the cleaning blade 17a is driven. The intermediate transfer belt 16 is in contact with a portion where the intermediate transfer belt 16 is wound around the roller 15.

  Further, on the back surface of the belt surface 16a facing downward in the transport direction of the intermediate transfer belt 16, a primary transfer member 21 made of a leaf spring electrode is opposed to an image carrier 20 of each image forming station Y, M, C, K described later. Is contacted by the elastic force, and a transfer bias is applied to the primary transfer member 21. A test pattern sensor 18 is installed on the support frame 9 a of the transfer belt unit 9 in the vicinity of the drive roller 14. This test pattern sensor 18 is a sensor for positioning each color toner image on the intermediate transfer belt 16, detecting the density of each color toner image, and correcting the color shift and image density of each color image.

  The image forming unit 6 includes image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (for black) that form a plurality (four in this embodiment) of different color images. As shown in detail in FIG. 2, each of the image forming stations Y, M, C, and K has an image carrier 20 formed of a photosensitive drum and a charging unit 22 disposed around the image carrier 20. The image writing unit 23 and the developing unit 24 are provided. The order of arrangement of the image forming stations Y, M, C, and K is arbitrary.

  Then, the image carrier 20 of each of the image forming stations Y, M, C, and K is brought into contact with the belt surface 16a facing downward in the transport direction of the intermediate transfer belt 16, and as a result, each of the image forming stations Y, M. , C and K are also arranged in a direction inclined to the left in the drawing with respect to the drive roller 14. The image carrier 20 is rotationally driven in the conveyance direction of the intermediate transfer belt 16 as indicated by the arrows in the figure.

The charging means 22 is composed of a conductive brush roller connected to a high voltage generating source, rotates in the same direction as the image carrier 20 as an image carrier, and abuts at a peripheral speed of 2 to 3 times. Thus, the surface of the image carrier 20 is uniformly charged. The conductive brush roller is a square inch of semiconductive fibers having a diameter of 2 to 6 denier and a yarn resistance of 10 ⁷ to 10 ⁹ Ω on the surface of a highly conductive shaft member (for example, a metal shaft) having a diameter of 5 to 8 mm. 150,000 to 430,000 pile-woven fabrics are wound in a spiral shape, and are held rotatably so that the contact depth with respect to the image carrier 20 is 0.3 to 0.5 mm.

  When a negatively chargeable image carrier is used as the image carrier 20, the voltage applied to the brush roller is a voltage obtained by superimposing an alternating current component having a frequency of about 1 KHz on a direct current component -300 to -500V and 800 to 1300V. It is desirable. In addition, when an image forming method having a cleaner-less configuration is used as in the present embodiment, the transfer residual toner adhered to the brush roller by applying a bias having a polarity opposite to the toner and the charging polarity to the brush roller during non-image formation. It is desirable that the toner is discharged onto the image carrier 20, transferred onto the intermediate transfer belt 16 at the primary transfer portion, and collected by the cleaning means 17 of the intermediate transfer belt 16.

  By using such a charging means 22, the surface of the image carrier can be charged with an extremely small current, so that the inside and outside of the apparatus is not contaminated with a large amount of ozone unlike the corona charging method. In addition, since the contact with the image carrier 20 is soft, the transfer residual toner generated when the roller charging method is used is less likely to stick to the charging roller or the image carrier, and stable image quality and device reliability are ensured. Sex can be secured.

  The image writing means 23 uses an array-like writing head in which elements such as a liquid crystal shutter having a light emitting diode and a backlight are arranged in a line in the axial direction of the image carrier 20. The array-like writing head has an advantage that the optical path length is shorter than that of the laser scanning optical system and is compact, can be arranged close to the image carrier 20, and the entire apparatus can be downsized. In the present embodiment, the image carrier 20, the charging unit 22, and the image writing unit 23 of each of the image forming stations Y, M, C, and K are unitized as an image carrier unit 25 (FIG. 2) to form an array. The configuration is such that the positioning of the writing head is maintained, and when the image carrier unit 25 is replaced, it is exchanged including the array writing head, and the new image carrier unit is adjusted for light quantity and positioned for reuse. It is configured to do.

  Next, details of the developing unit 24 will be described on behalf of the image forming station K in FIG. In the present embodiment, the image stations Y, M, C, and K are disposed in an oblique direction, and the image carrier 20 is in contact with the belt surface 16a facing downward in the conveyance direction of the intermediate transfer belt 16, The toner storage container 26 is disposed obliquely downward. Therefore, a special configuration is adopted as the developing unit 24.

  That is, the developing unit 24 includes a toner storage container 26 that stores toner (hatched part in the drawing), a toner storage part 27 formed in the toner storage container 26, and a toner disposed in the toner storage part 27. The stirring member 29, the partition member 30 partitioned on the upper part of the toner storage portion 27, the toner supply roller 31 disposed above the partition member 30, and the toner supply roller 31 provided on the partition member 30 The developing roller 33 disposed so as to be in contact with the toner supply roller 31 and the image carrier 17, and the regulation blade 34 being in contact with the developing roller 33.

  The image carrier 20 is rotated in the conveying direction of the intermediate transfer belt 16, and the developing roller 33 and the supply roller 31 are rotationally driven in a direction opposite to the rotation direction of the image carrier 20, as shown by the arrows in the figure. The stirring member 29 is driven to rotate in the direction opposite to the direction of rotation of the supply roller 31. The toner stirred and carried up by the stirring member 29 in the toner storage unit 27 is supplied to the toner supply roller 31 along the upper surface of the partition member 30, and the supplied toner is rubbed against the blade 32 and slid on the supply roller 31. The toner is supplied to the surface of the developing roller 33 by a mechanical adhesion force to the surface uneven portion and an adhesion force by frictional band power. The toner supplied to the developing roller 33 is regulated to a predetermined thickness by the regulating blade 34, and the thinned toner layer is conveyed to the image carrier 20 so that the developing roller 33 and the image carrier 20 come into contact with each other. The latent image portion of the image carrier 20 is developed at the nip portion configured as described above and in the vicinity thereof.

Returning to FIG. 1, the paper feed unit 10 is a paper feed unit including a paper feed cassette 35 in which the recording media P are stacked and held, and a pickup roller 36 that feeds the recording media P from the paper feed cassette 35 one by one. It has.
In the first opening / closing member 3, a registration roller pair 37 that defines the feeding timing of the recording medium P to the secondary transfer unit, and a secondary transfer unit that is pressed against the drive roller 14 and the intermediate transfer belt 16. A secondary transfer unit 11, a fixing unit 12, a recording medium conveyance unit 13, a paper discharge roller pair 39, and a duplex printing conveyance path 40 are provided.

  The secondary transfer unit 11 includes a rotation lever 42 pivotally supported by a fixed shaft 41, a secondary transfer roller 19 rotatably provided at one end of the rotation lever 42, and a rotation lever 42. The secondary transfer roller 19 is normally moved in the direction of the arrow by the bias of the spring 43 to drive the intermediate transfer belt 16 and the drive. The roller 14 can be pressed. An eccentric cam 44 is provided on the spring 43 side of the rotation lever 42, and the rotation lever 42, the spring 43, and the eccentric cam 44 constitute a means for separating and contacting the secondary transfer roller 19. Then, the rotation of the eccentric cam 44 causes the rotation lever 42 to rotate against the spring 43 so that the secondary transfer roller 19 is separated from the intermediate transfer belt 16.

  The fixing unit 12 includes a heating roller 45 that includes a heating element such as a halogen heater and is rotatable, a pressure roller 46 that presses and biases the heating roller 45, and is swingable on the pressure roller 46. The belt tension member 47, and the heat-resistant belt 49 stretched between the pressure roller 45 and the belt tension member 47, and the color image secondarily transferred to the recording medium are the heat roller 45 and the heat-resistant belt 49. The toner image is fixed on the recording medium at a predetermined temperature at the nip portion formed in step (b). In the present embodiment, the fixing unit 12 can be disposed in a space formed obliquely above the intermediate transfer belt 16, in other words, in a space opposite to the image forming unit 6 with respect to the intermediate transfer belt 16. Thus, heat transfer to the electrical component box 5, the image forming unit 6, and the intermediate transfer belt 16 can be reduced, and the frequency of performing the color misregistration correction operation for each color can be reduced.

  In the image forming apparatus of the present embodiment, as shown in FIG. 1, the intermediate transfer belt 16 and the image forming stations Y, M, C, and K are arranged obliquely in the housing main body 2, and the electrical component box 5 is arranged in each case. Arranged vertically below the image forming stations Y, M, C, and K. Then, the wiring (shown by the two-dot chain line in FIG. 1) from the power supply circuit in the electrical component box 5, the drive circuit, the control circuit, etc. (shown by the two-dot chain line in FIG. The image writing means 23 and the test pattern sensor 18 are detachably connected. The secondary transfer unit 11 and the fixing unit 12 in the first opening / closing member 3 may be wired via the connector 50, or may be wired near the rotating shaft 3b of the first opening / closing member 3. May be.

The outline of the operation of the entire image forming apparatus as described above is as follows.
(1) When a print command signal (image formation signal) from a host computer (not shown) or the like (personal computer or the like) is input to the control circuit in the electrical component box 5, each image forming station Y, M, C, K The image carrier 20, the rollers of the developing unit 24, and the intermediate transfer belt 16 are driven to rotate.
(2) The surface of the image carrier 20 is uniformly charged by the charging means 22.
(3) The surface of the image carrier 20 that is uniformly charged in each image forming station Y, M, C, K is selectively exposed according to the image information of each color by the image writing means 23, and for each color. Electrostatic latent image is formed.
(4) The electrostatic latent images formed on the respective image carriers 20 are developed with toner images by the developing means 24.
(5) The primary transfer member 21 of the intermediate transfer belt 16 is applied with a primary transfer voltage having a polarity opposite to the charged polarity of the toner, and the toner image formed on the image carrier 20 is transferred to the intermediate transfer belt at the primary transfer portion. The images are successively transferred onto the intermediate transfer belt 16 in accordance with the movement of 16.
(6) In synchronization with the movement of the intermediate transfer belt 16 on which the primary image has been primarily transferred, the recording medium P stored in the paper feed cassette 35 is fed to the secondary transfer roller 19 through the registration roller pair 37. Is done.
(7) The primary transfer image is merged with the recording medium at the secondary transfer site, and the secondary transfer roller 19 pressed against the driving roller 14 of the intermediate transfer belt 16 by the pressing mechanism. A reverse-polarity bias is applied, and the primary transfer image formed on the intermediate transfer belt 16 is secondarily transferred to the synchronously fed recording medium.
(8) The transfer residual toner in the secondary transfer is conveyed in the direction of the driven roller 15 and scraped off by the cleaning means 17 disposed opposite to the roller 15, and the intermediate transfer belt 16 is refreshed. Once again, the above cycle can be repeated.
(9) The toner image on the recording medium is fixed by passing the recording medium through the fixing unit 12, and then the recording medium is directed to a predetermined position (or double-sided printing toward the paper discharge tray 4 if not double-sided printing). In this case, the sheet is conveyed toward the conveyance path 40 for double-sided printing.

  Next, features of the present invention will be described. FIG. 3 is a diagram showing an embodiment of the image forming apparatus of the present invention. In the figure, 50 is an image carrier unit as an example of a rotating body unit, 51 is an image carrier as an example of a rotating body, 52 is a hub, 52a is a connection portion, 53 is a shaft, 54 is a housing, and 60 is a holding member. , 61 is a first outer plate as an example of a first shaft holding member, 62 is an inner plate as an example of a rotating member driving means holding member, and 62a is an image carrier driving gear holding as an example of a rotating member driving means holding portion. , 63 is a second outer plate as an example of the second shaft holding member, 70 is an image carrier driving unit as an example of the rotating body driving unit, 71 is an image carrier driving gear as an example of the rotating body driving means, 71a is a connecting portion, 71b is a tooth, and 71c is a groove.

  The image carrier unit 50 includes an image carrier 51, a hub 52, a shaft 53, and a housing 54. The image carrier 51 is provided with a hub 52 at an end, is a cylindrical member, and a shaft 53 passes through the center. The hub 52 is provided at an end portion of the image carrier 51 and has a connection portion 52a that supports the shaft 53 and is connected to the image carrier driving portion 70 side. The connecting portion 52a has teeth having a shape that transmits a driving force. The shaft 53 passes through the image carrier 51, the hub 52 and the image carrier drive unit 70, and is supported by the holding member 60 at both ends. The housing 54 is a member supported by the shaft 53.

  The holding member 60 includes a first outer plate 61, an inner plate 62 and a second outer plate 63. The first outer plate 61 and the second outer plate 63 are provided outside the image carrier unit 50 and the rotator driving unit 70, and support the shaft 53 at the front and rear portions with respect to the insertion direction of the image carrier unit 50. The second outer plate 63 can be opened and closed. The inner plate 62 is provided between the first outer plate 61 and the second outer plate 63 and between the image carrier unit 50 and the image carrier driving unit 70, and is made of sheet metal or resin. The image carrier driving means holding portion 62a is a portion formed in the inner plate 62 and protruding into the groove 71c of the image carrier driving means 71 described later. The holding member 60 may be used as a ground for the image carrier 51 using a conductive material.

  The image carrier driving unit 70 has an image carrier driving gear 71. The image carrier drive gear 71 is held by the inner plate 62 between the first outer plate 61 and the image carrier unit 50 and the inner plate 62 before the shaft 53 is inserted, and is supported by the shaft 53 after the shaft 53 is inserted. It is rotationally driven by a driving force such as a motor (not shown), and drives the image carrier unit 50 by the driving force. The connection portion 71 a is a portion that is connected to a connection portion 52 a provided on the hub 52 of the image carrier 51 and transmits a driving force to the image carrier 51. The teeth 71b are provided on the outer periphery of the image carrier driving gear 71 and receive a driving force such as a motor (not shown). The groove 71c is a concave portion provided annularly on the outer side of the through hole through which the shaft 53 passes, and is a portion where the image carrier driving means holding portion 62a of the inner plate 62 protrudes inside.

  When the image carrier driving unit 70 is assembled to the holding member 60, a shaft-shaped jig is inserted into the hole from the outside of the first outer plate 61 of the holding member 60, and the image carrier driving gear 71 and the inner plate 62 are inserted. Are assembled by sequentially fitting them into the jig.

  When using the image carrier unit 50, the holding member 60, and the image carrier drive unit 70 of such an image forming apparatus, first, the second outer member 63 is opened and the image carrier unit 50 is inserted. At this time, in a state where the image carrier unit 50 is not inserted, a motor or the like (not shown) or the image carrier driving unit 70 may be set not to be driven. Next, after the image carrier unit 50 is inserted, the image carrier driving gear 71 is rotationally driven by a driving force such as a motor (not shown), and the driving force of the image carrier driving gear 71 is transmitted from the connecting portion 71a to the hub 52. It is actuated by being transmitted to the image carrier 51 through the connecting portion 52a. At this time, the shaft 53 may rotate with the image carrier 51 or may not rotate. When the shaft 53 is not rotated, the straightness of the shaft itself does not occur and the image carrier 51 can be rotated with high accuracy. Since the first outer plate 61 supporting the shaft 53 is provided on the back side of the image carrier driving gear 71 as viewed from the insertion direction of the image carrier 51 as described above, the shaft 53 of the image carrier 51 is used as a through shaft. As a result, the positional accuracy of the image carrier 51 is improved.

  4A shows a state of the holding member 60 and the image carrier driving unit 70 before or after the image carrier unit 50 is inserted, and FIG. 4B shows a cross-sectional view taken along line AA. In the figure, h1 is the height of the tooth, and h2 is the fall amount. Before or after the image carrier unit 50 is inserted or removed, the image carrier driving gear 71 of the image carrier driving unit 70 does not have the shaft 53 to be supported. The outer periphery or the inner periphery is held by the protruding portion 62a of the inner plate 62. At this time, if the fall amount h2 is not set lower than the tooth height h1 of the image carrier driving gear 71, the tooth engagement with the gear G upstream of the image carrier driving gear 71 will be disengaged. The distance from the protrusion 62a to the outer periphery or inner periphery of the groove 71c of the image carrier driving gear 71 is made smaller than h1. That is, the moving distance of the image carrier drive gear 71 when the image carrier unit 50 is not inserted from the state where the image carrier unit 50 is inserted is the tooth distance of the image carrier drive gear 71. By setting the height shorter than the height, the tooth engagement with the gear upstream of the image carrier driving gear 71 will not be lost.

  FIG. 5 shows another embodiment of the connecting portion 52 a provided on the hub 52 of the image carrier 51 and the connecting portion 71 a of the image carrier driving gear 71. Both of the connecting portions 52a and 71a have trapezoidal peaks and valleys alternately, and have a shape in which driving force is transmitted only in one direction of rotation.

  6 and 7 are views showing another embodiment of the holding member 60, FIG. 6 is a perspective view, and FIG. 7 is a cross-sectional view. In the figure, 61a is a first extension part, and 61b is a second extension part. The first extending portion 61a is a portion that extends outward from the outer periphery of the image carrier driving gear 71 from the first outer plate 61, and the second extending portion 61b further extends from the first extending portion 61a. This is a portion extending toward the center of the carrier driving gear 71. In this embodiment, the image carrier driving gear 71 can be held without providing the inner plate 62. In this case, if the first outer plate 61 is made of an elastically deformable resin, the image carrier driving gear 71 can be easily assembled. 4 and 5, since the image carrier drive gear 71 of the image carrier drive unit 70 does not have the shaft 53 to be supported before or after the image carrier unit 50 is inserted or removed, It falls entirely under the influence of gravity and is held by the inner periphery of the first extending portion 61 a of the first outer plate 61. At this time, if the fall amount h2 is not set lower than the tooth height h1 of the image carrier driving gear 71, the tooth engagement with the gear upstream of the image carrier driving gear 71 will be disengaged. The distance between the inner circumference of 61 and the outer circumference of the image carrier driving gear 71 may be smaller than h1. Since the inner plate 62 need not be used in this way, the number of parts is reduced, the manufacturing cost is reduced, and the assembly is facilitated.

  FIG. 8 is a view showing another embodiment of the image carrier driving gear 71. In the figure, 71d is a convex part. In this embodiment, the convex portion 71d of the image carrier driving gear 71 is supported by the first outer plate 61, and the other portions are the same as in FIG. By adopting a structure in which the convex portion 71d of the image carrier driving gear 71 is supported by the first outer plate 61 in this way, the image carrier driving gear 71 is prevented from falling off and disengaged from the upstream gear. Can be prevented.

  FIG. 9 is a view showing another embodiment of the image carrier driving gear 71. In this embodiment, the outer shape of the image carrier driving gear 71 is made larger than the outer shapes of the image carrier 51 and the housing 54. That is, the outer shape of the image carrier drive gear 71 has a larger portion than the image carrier unit when projected from the insertion direction of the image carrier unit 50. The image carrier driving gear 71 is separate from the image carrier unit 50, and the first outer plate 61 that supports the shaft 53 is disposed on the back side of the image carrier driving gear 71 when viewed from the insertion direction of the image carrier 51. Since it is provided, it is possible to make it larger than the outer shape of the image carrier 51 and the casing 54. Then, the number of teeth of the image carrier driving gear 71 is increased, the accuracy is improved, and the rotation unevenness is reduced, so that the quality is improved.

  FIG. 10 is a diagram showing another embodiment of the image carrier driving unit 70, FIG. 10 (a) is a diagram before the image carrier unit 50 is inserted, and FIG. 10 (b) is the image carrier unit 50. It is a figure after inserting. In the figure, reference numeral 72 denotes an image carrier driving part spring as an example of a rotating body driving part spring. In this embodiment, a spring 72 is installed between the first outer plate 61 and the image carrier driving gear 71. By installing the image carrier driving section spring 72 in this way, as shown in FIG. 10A, before or after the image carrier unit 50 is inserted, the image carrier driving gear 71 is affected by gravity. 10a and 10b, when the image carrier unit 50 is inserted, the connecting portion between the image carrier 51 and the image carrier driving gear 71 as shown in FIG. Even when the phases do not match at 51a and 71a and the projections and depressions collide with each other, the image carrier driving part spring 72 contracts, so that the image carrier driving gear 71 can slide in the direction of the axis 53, so that the second outer plate 63 can be closed. Then, when the image carrier 51 rotates, the phases are matched, and the image carrier 51 and the image carrier drive gear 71 are connected.

  11 and 12 are diagrams showing another embodiment of the present invention. In the figure, 52b is a second connection projection, 55 is an image carrier spring as an example of a pressurizing mechanism, 62b is a hole, 71e is a first connection projection, 73 is a holder, 73a is a projection, and 74 is a coupling. 74a is a first connection recess, 74b is a second connection recess, 74c is a wall, and 75 is a coupling spring as an example of an elastic member. In the present embodiment, the connection portion 71a of the image carrier driving gear 71 and the connection portion 52a of the hub 52 are connected via a holder 73, a coupling 74, and a coupling spring 75.

  The holder 73 is a cylindrical member fixed by inserting the protrusion 73 a into the hole 62 b of the inner plate 62, and includes the coupling 74 and the coupling spring 75. The coupling 74 is a cylindrical member included in the holder 73, and has a first connection recess 74a, a second connection recess 74b, and a wall 74c on the inner periphery. The first connection concave portion 74a is coupled to the first connection convex portion 71e provided in the connection portion 71a of the image carrier driving gear 71 so as to be axially slidable. The second connection concave portion 74b is coupled to the second connection convex portion 52b provided in the connection portion 52a of the hub 52 so as to be axially slidable. The first connection convex portion 71e provided in the connection portion 71a of the image carrier driving gear 71 and the first connection concave portion 74a of the coupling 74 do not relatively move in the circumferential direction so that the hub 52 is connected. The second connection convex portion 52b provided on the portion 52a and the second connection concave portion 74b of the coupling 74 are relatively rotatable in the circumferential direction by enlarging the second connection concave portion 74b in the circumferential direction. To do. By adopting such a structure, the first connecting convex portion 71e provided in the connecting portion 71a of the image carrier driving gear 71 and the first connecting concave portion 74a of the coupling 74 can transmit the driving force instantaneously. In addition, the second connection convex portion 52b provided in the connection portion 52a of the hub 52 and the second connection concave portion 74b of the coupling 74 can be easily inserted when the image carrier unit 50 is assembled to the main body. The wall 74 c separates the connection portion 71 a of the image carrier driving gear 71 from the connection portion 52 a of the hub 52, and is provided on the inner periphery of the coupling 74.

  The coupling spring 75 is provided between the image carrier driving gear 71 and the coupling 74 on the inner periphery of the holder 73, and is a spring spring that allows the coupling 74 to slide in the axial direction. The two outer plates 62 are biased in the direction.

  With such a structure, when the image carrier unit 50 is inserted into the holding member 60, the connection portion 52 a of the hub 52 is first inserted into the coupling 74. At this time, if the second connection convex portion 52b of the connection portion 52a is fitted into the second connection concave portion 74b of the coupling 74, it is inserted as it is. However, when the second connection convex portion 52b of the connection portion 52a does not fit into the second connection concave portion 74b of the coupling 74, the entire coupling 74 slides in the axial direction against the urging force of the coupling spring 75. Then, the second outer plate 62 can be closed. Thereafter, when the image carrier driving gear 71 rotates during driving, the second connection convex portion 52 b of the connection portion 52 a is fitted into the second connection concave portion 74 b of the coupling 74. That is, the image carrier unit 50 can be easily set without considering the phase between the hub 52 of the image carrier unit 50 and the image carrier driving gear 71. Further, by positioning the holder 73 in the groove 71c of the image carrier driving gear 71, the space in the axial direction can be shortened.

  Next, the image carrier spring 55 will be described. The image carrier spring 55 is provided between the image carrier 51 and the housing 54 in the housing 54 of the image carrier unit 50, and the image carrier 51 is connected to the image carrier driving gear 71 side in the axial direction, on the image carrier. The unit 50 is biased toward the front side in the insertion direction. By adopting such a structure, the coupling between the image carrier driving gear 71 and the image carrier can be ensured. In the present embodiment, the spring is used. However, the present invention is not limited thereto, and any spring may be used as long as it biases or presses the image carrier 51 toward the image carrier drive gear 71 in the axial direction.

  FIG. 13 is a perspective view seen from the second outer plate 63 side. The shaft 53 is supported by the first outer member 61 and the second outer plate 63 and passes through the second outer plate 63. With such a structure, the shaft 53 is more stable and the positional accuracy of the image carrier 51 is improved. Also, by providing a plurality of image carriers 51 and supporting their shafts 53 with one first outer plate 61 and one second outer plate 63, the accuracy of stacking parts is improved, and the image carrier is improved. The position accuracy of the body 51 is improved.

  In this embodiment, the image carrier unit 50 has been described as an example of a rotating body. However, the present invention can also be applied to a rotating body that does not include the casing 54 as shown in FIG. 14, such as a developing roller or a charging roller.

1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. The figure which shows one Embodiment of this invention The figure which shows the state after extracting the axis | shaft of FIG. The figure which shows other embodiment of a connection part. The perspective view which shows other embodiment of a holding member The figure which shows other embodiment of a holding member The figure which shows other embodiment of an image carrier drive gear. The figure which shows other embodiment of an image carrier drive gear. The figure which shows other embodiment of an image carrier drive part. The figure which shows other embodiment of this invention The figure which shows other embodiment of this invention The figure which shows other embodiment of an image carrier drive gear. The figure which shows other embodiment of this invention

Explanation of symbols

  25, 50: Image carrier unit (rotating body unit), 20, 51: Image carrier (rotating body), 52: Hub, 52a ... Connection portion, 52b is second connection convex portion, 53 ... Shaft, 54 ... Housing , 60 ... holding member, 61 ... first outer plate (first shaft holding member), 61a ... first extending portion, 61b ... second extending portion, 62 ... inner plate (rotating body driving means holding member), 62a ... image carrier driving gear holding part (rotating body driving means holding part), 62b ... hole, 63 ... second outer plate (second shaft holding member), 70 ... image carrier driving part (rotating body driving part), 71 ... image carrier driving gear (rotating body driving means), 71a ... connecting portion, 71b ... teeth, 71c ... groove, 71d ... convex portion, 71e ... first connecting convex portion, 72 ... image carrier driving portion spring (pressure) Mechanism) 73 ... Holder, 73a ... Projection, 74 ... Coupling, 74a ... First connection recess, 74b ... Second contact Recess, 74c ... wall, 75 ... coupling spring (elastic member)

Claims (9)

A first shaft holding member that supports one end of both ends of a shaft that penetrates and supports the image carrier;
A second shaft holding member that supports the other end of the shaft;
A rotating body drive unit having a through hole through which the shaft passes and having a rotating body driving means for driving the image carrier;
Rotating body drive for holding the rotating body driving means between the first shaft holding member and the image carrier and for holding the rotating body driving means movably in directions other than the axial direction of the shaft. Means holding part;
An image forming apparatus comprising: The rotating body driving means is a gear, and a moving distance in which the gear moves in a direction perpendicular to the axial direction out of directions other than the axial direction is shorter than a tooth height of the gear. The image forming apparatus according to claim 1 . Said rotating body driving means, when projected from the insertion direction of the image bearing member, an image forming apparatus according to claim 1 or claim 2, characterized in that it has the image bearing member a larger portion. The axis is the image forming apparatus according to any one of claims 1 to 3, characterized in that a non-rotating. It said rotating body driving means, the image forming apparatus according to any one of claims 1 to 4, wherein the slidable in the axial direction. A first shaft holding member that supports one end of both ends of a shaft that penetrates and supports the image carrier;
A second shaft holding member that supports the other end of the shaft;
A rotating body driving unit having rotating body driving means for driving the image carrier;
A rotating body driving means holding member for holding the rotating body driving unit;
With
The rotating body drive unit is
The rotating body driving means having a groove concentric with the shaft;
A holder held by the rotating body driving means holding member;
A coupling that connects between the image carrier and the rotating body driving means in the holder and is slidable in the axial direction;
An elastic member that allows the coupling to slide;
Have
An image forming apparatus according to claim 1, wherein at least a part of the coupling is movable into the groove of the rotating body driving unit. It said image bearing member, an image forming apparatus according to claim 6, characterized in Rukoto pressed against the image bearing member inserting direction front side by the pressing mechanism. Wherein the image forming apparatus, an image forming apparatus according to any one of claims 1 to 7, characterized in that including a plurality of said image bearing member and said rotating body driving unit. The image forming apparatus according to claim 1, wherein the shaft that supports and penetrates is a shaft that penetrates and supports a developing roller or a charging roller instead of the image carrier.

Images