JP2014056183A - Drawer unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drawer unit capable of suppressing damage to a plurality of link members for transmitting driving force to members of a transfer device, and suppressing loss of durability of the plurality of link members; and an image forming apparatus.SOLUTION: In a plurality of link members, an input link member 713 is fixed to an input part, and a coupling link member 712 is coupled to the input link member 713; and a long hole 712a is formed on any one of the link members 712 and 713, and a fitting projection 713a fitted to the long hole 712a is formed on the other. The fitting projection 713a is fitted to the long hole 712a, so as to couple the input link member 713 and the coupling link member 712.

Description

  The present invention relates to a drawer unit and an image forming apparatus.

  Japanese Patent Application Laid-Open No. 2004-228561 includes a drawer unit configured to hold a transfer device that transfers a toner image on an intermediate transfer belt serving as an image carrier onto a recording sheet serving as a transfer medium and can be pulled out from the image forming apparatus. An image forming apparatus is described. In the image forming apparatus described in Patent Document 1, the transfer apparatus includes a contact / separation mechanism that contacts and separates a secondary transfer roller as a transfer member that contacts the intermediate transfer belt from the intermediate transfer belt, and includes a drawer unit. When pulling out, the contact / separation mechanism is driven so that the secondary transfer roller is separated from the intermediate transfer belt and then pulled out.

  In the transfer device, an input gear meshed with a secondary transfer roller drive gear provided in the apparatus main body to which a driving force is transmitted from the secondary transfer roller drive motor, and fixed to the shaft of the secondary transfer roller and meshed with the input gear. A roll shaft gear is provided. In addition, a contact / separation input gear that meshes with a contact / separation drive gear provided in an apparatus main body to which a driving force is transmitted from a contact / separation drive motor for driving the contact / separation mechanism is also provided.

  When the drawer unit is mounted on the apparatus main body, the input gear meshes with the secondary transfer roller driving gear provided on the apparatus main body, and the driving force is transmitted to the secondary transfer roller from the secondary transfer roller driving motor provided on the apparatus main body. The secondary transfer roller can be rotationally driven. Further, the contact / separation input gear meshes with the contact / separation drive gear of the apparatus main body, so that the drive force can be transmitted from the contact / separation drive motor provided in the apparatus body to the contact / separation mechanism, and the secondary transfer roller Can be separated.

  However, in the image forming apparatus described in Patent Document 1, when the drawer unit is mounted on the apparatus body, the teeth of the input gear may collide with the teeth of the secondary transfer roller drive gear, The teeth of the drive gear for contact / separation may collide with the teeth of the gear.

The present applicant is developing an image forming apparatus in which a pull-out unit is provided with a contact / separation drive device for driving a contact / separation mechanism provided in the secondary transfer device.
FIG. 27 is a front view of the drawer unit 500 under development.
The drawer unit 500 under development holds a secondary transfer device 350 as a transfer device. The secondary transfer device 350 includes a secondary transfer roller 24 as a transfer member that contacts an unshown intermediate transfer belt, and a contact / separation mechanism (not shown) that makes the secondary transfer roller 24 contact and separate from the intermediate transfer belt. It has. Further, the side plate 504 of the drawer unit 500 under development is provided with a contact / separation drive device 700 for driving the contact / separation mechanism of the secondary transfer device 350. The contact / separation drive device 700 includes a drive unit 710a as drive means including a contact / separation drive motor 701 and the like. Also, the contact / separation drive device 700 has an input shaft 361 as an input portion provided in a secondary transfer device 350 for driving a contact / separation mechanism (not shown) from an output shaft 703 as an output portion of the drive portion 710a. A link mechanism 710b is provided as a drive transmission mechanism that transmits drive to the vehicle. The link mechanism 710b includes an output link member 711 fixed to the output shaft 703, an input link member 713 fixed to the input shaft 361, and a connection link member 712 that connects the output link member 711 and the input link member 713. It is configured.

  The driving force of the contact / separation drive motor 701 is transmitted to a plurality of drive transmission members provided inside the case 702 of the drive unit 710 a and is transmitted to the output shaft 703 of the drive unit 710 a protruding from the case 702. The driving force transmitted to the output shaft 703 is transmitted to the link mechanism 710. Then, the driving force of the contact / separation drive motor 701 is transmitted to the input shaft 361 provided in the secondary transfer device via the link mechanism 710b, and the contact / separation mechanism (not shown) in the secondary transfer device is driven, and the secondary transfer device is driven. The transfer roller 24 contacts and separates from an intermediate transfer belt (not shown).

  As described above, the contact / separation drive motor 701 is provided in the drawer unit 500 as a drive unit for driving the contact / separation mechanism of the secondary transfer apparatus 350, so that when the apparatus main body of the drawer unit 500 is mounted, the secondary transfer apparatus 500 is installed. There is no need to contact the drive transmission member on the apparatus main body side that transmits drive to the contact / separation mechanism and the drive transmission member on the drawer unit side. This can prevent the contact / separation drive transmission member from being damaged when the drawer unit 500 is attached to the apparatus main body.

  In the drawer unit 500 under development, the drawer unit 500 includes only a driving unit that drives a contact / separation mechanism that contacts and separates the secondary transfer roller 24 with respect to the intermediate transfer belt. Driving means for driving 24 may be provided in the drawer unit. Of course, only the driving means for driving the secondary transfer roller 24 may be provided in the drawer unit 500. In the drawer unit 500 under development, a motor is used as a driving means for driving the contact / separation mechanism. However, an operating lever is provided as the driving means, and a driving force is generated by operating the operating lever of the operator. The contacting / separating mechanism may be driven.

  However, the positional relationship between the output shaft 703 and the input shaft 361 is a prescribed positional relationship due to the assembly error of the secondary transfer device 350 with respect to the drawer unit 500 and the assembly error of the contact / separation drive device 700 with respect to the drawer unit 500. May be out of position. When the positional relationship between the output shaft 703 and the input shaft 361 is displaced with respect to a specified position, a large stress is applied to the plurality of link members 711, 712, and 713 constituting the link mechanism 710 during drive transmission, and the durability of the link member is increased. There was a problem that the property was impaired.

  The above-mentioned problem is also a problem that occurs in the drive transmission using gears. That is, when the positional relationship between the output shaft 703 and the input shaft 361 is displaced with respect to a specified position, the gear fixed to the input shaft 361 and the gear provided on the side plate on the drawer unit side that meshes with the gear. A large stress is applied to the meshing, resulting in a problem that the gear durability is impaired.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to prevent damage to a plurality of link members for transmitting a driving force to a member of a transfer device, and to ensure durability of the plurality of link members. To provide a drawer unit and an image forming apparatus capable of suppressing damage, to prevent damage to a plurality of gears for transmitting a driving force to a member of a transfer device, and to durability of the plurality of gears It is an object of the present invention to provide a drawer unit and an image forming apparatus that can suppress the deterioration of performance.

  In order to achieve the above object, a first aspect of the present invention provides a drawer unit that includes a holding body that holds a transfer device that transfers an image of an image carrier to a transfer medium, and is configured to be drawn out from the image forming apparatus. A drive means for generating a drive force, and a plurality of link members for transmitting the drive force of the drive means from an output portion of the drive means to an input portion of the transfer device, and the link member among the plurality of link members A long hole is formed in one of the input link member fixed to the input portion and the connecting link member connected to the input link member, and a fitting protrusion that fits into the long hole is formed in the other. The input link member and the connecting link member are connected by fitting the fitting protrusion into the elongated hole.

  According to a fourth aspect of the present invention, in a drawer unit that includes a holder that holds a transfer device that transfers an image on an image carrier onto a transfer medium and that is configured to be drawable with respect to the image forming apparatus, a driving force is generated. And a plurality of gears for transmitting the driving force of the driving unit from the output unit of the driving unit to the input unit of the transfer device, one of the plurality of gears being fixed to the input unit An input gear, wherein a gear meshing with the input gear among a plurality of gears is held movably with respect to a holding body.

  According to the first aspect of the present invention, since the drive unit for driving the member of the transfer device is provided in the drawer unit, the drive transmission member and the drawer on the device main body side are different from Patent Document 1 in which the drive unit is provided in the device main body. There is no need to contact the drive transmission member on the unit side. Thereby, when the drawer unit is mounted on the apparatus main body, it is possible to prevent the drive transmission member from being damaged. Further, even when the positional relationship between the output unit of the driving unit and the input unit of the transfer device is displaced with respect to a predetermined positional relationship, it is possible to suppress a large stress from being applied to the plurality of link members. It can suppress that durability of this link member falls.

  According to the invention of claim 4, since the driving unit for driving the member of the transfer device is provided in the drawer unit, the driving transmission member on the device main body side is different from Patent Document 1 in which the driving device is provided in the device main body. There is no need to contact the drive transmission member on the drawer unit side. Thereby, when the drawer unit is mounted on the apparatus main body, it is possible to prevent the drive transmission member from being damaged. Further, even when the positional relationship between the output unit of the driving unit and the input unit of the transfer device is deviated from a predetermined positional relationship, it is possible to suppress a large stress from being applied to the plurality of gears. It can suppress that the durability of a gear falls.

1 is a schematic configuration diagram showing a copying machine. FIG. 3 is a perspective view of the copying machine showing a state when the drawer unit is pulled out. The perspective view of a part vicinity of a drawer unit. The perspective view of the vicinity of the location different from FIG. 3 of a drawer unit. The perspective view which shows the rear side of a secondary transfer unit. The perspective view which shows the front side of a secondary transfer unit. The front view which shows a rear side holding member. The front view which shows the rear side holding member in the state which has located the secondary transfer roller in the separation position. The perspective view which shows the drawer unit front board and the front side of a secondary transfer unit. FIG. 4 is an enlarged plan view showing the vicinity of a drawer unit front side fixing portion of a secondary transfer unit. FIG. 4 is an enlarged perspective view showing the vicinity of a drawer unit front side fixing portion of a secondary transfer unit. The perspective view which shows the drawer unit rear side plate and the rear side of the secondary transfer unit. FIG. 4 is an enlarged plan view showing the vicinity of a drawer unit rear side fixing portion of a secondary transfer unit. FIG. 4 is an enlarged perspective view showing the vicinity of a drawer unit rear side fixing portion of a secondary transfer unit. The perspective view which shows the transfer unit rear side board of a transfer unit. The perspective view which shows the transfer unit front side board of a transfer unit. The perspective view which shows a mode that the secondary transfer unit was positioned by the transfer unit. The schematic block diagram of a cancellation | release drive mechanism. The schematic block diagram which shows the principal part of the main body rear side board of an apparatus main body. The perspective view of FIG. The figure which shows the state by which fixation of the drawer unit was cancelled | released. The perspective view of FIG. The figure which shows the state of a link mechanism in the state where fixation of the drawer unit was cancelled | released. The figure explaining operation | movement of the conventional link mechanism when the position of an input shaft fluctuates, and operation | movement of the link mechanism of this embodiment. The figure which shows the modification of a cancellation | release drive mechanism. The schematic block diagram which shows an example in the case of performing the drive transmission from an output shaft to an input shaft with a gear. Schematic block diagram of a conventional drawer unit.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter simply referred to as a copying machine 1) will be described.
FIG. 1 is a schematic configuration diagram showing a copying machine 1. The copying machine includes a printer unit 100, a paper feeding unit 200, a scanner unit 300, and an automatic document feeder (hereinafter referred to as ADF) 400 as a sheet material feeder supported by the printer unit 100.

  The printer unit 100 includes an endless belt-shaped intermediate transfer belt 10 as an image carrier. The intermediate transfer belt 10 is wound around the driving roller 14, the driven roller 15 and the secondary transfer counter roller 16 in a posture in which the side view is an inverted triangle shape. It can be moved endlessly in the clockwise direction. Above the intermediate transfer belt 10, four image forming units 18Y, 18M, 18C, and 18K for forming toner images of Y (yellow), M (magenta), C (cyan), and K (black) are provided. Arranged along the belt moving direction.

  The image forming units 18Y, 18M, 18C, and 18K include photoreceptors 20Y, 20M, 20C, and 20K, developing units 61Y, 61M, 61C, and 61K, and photoreceptor cleaning devices 63Y, 63M, 63C, and 63K. Yes. The photoconductors 20Y, 20M, 20C, and 20K are in contact with the intermediate transfer belt 10 to form primary transfer nips for Y, M, C, and K, respectively, and are rotated counterclockwise in the drawing by driving means (not shown). It can be driven to rotate. The developing units 61Y, 61M, 61C, and 61K are for developing the electrostatic latent images formed on the photoconductors 20Y, 20M, 20C, and 20K with Y, M, C, and K toners. Further, the photoconductor cleaning devices 63Y, 63M, 63C, and 63K clean the transfer residual toner adhering to the photoconductors 20Y, 20M, 20C, and 20K after passing through the primary transfer nip. In this printer, a tandem image forming unit is configured by four image forming units 18Y, 18M, 18C, and 18K arranged in the belt moving direction.

  In the printer unit 100, an optical writing unit 21 is disposed above the tandem image forming unit. The optical writing unit 21 performs an optical writing process by optical scanning on the surfaces of the photoconductors 20Y, 20M, 20C, and 20K that are driven to rotate counterclockwise in the drawing to form an electrostatic latent image. Is. Prior to the optical writing process, the surfaces of the photoreceptors 20Y, 20M, 20C, and 20K are uniformly charged by the uniform charging means of the image forming units 18Y, 18M, 18C, and 18K, respectively.

  The transfer unit 600 including the intermediate transfer belt 10 and the like has primary transfer rollers 62Y, 62M, 62C, and 62K inside the loop of the intermediate transfer belt 10. These primary transfer rollers 62Y, 62M, 62C, and 62K press the intermediate transfer belt 10 toward the photoreceptors 20Y, 20M, 20C, and 20K behind the primary transfer nips for Y, M, C, and K. Yes.

  A secondary transfer roller 24 as a transfer member is disposed below the intermediate transfer belt 10. The secondary transfer roller 24 is in contact with the portion of the intermediate transfer belt 10 that is wound around the secondary transfer counter roller 16 from the belt front surface side to form a secondary transfer nip. A sheet-like recording medium (hereinafter referred to as a recording sheet) is fed into the secondary transfer nip at a predetermined timing. Then, the four-color superimposed toner image on the intermediate transfer belt 10 is secondarily transferred onto the recording sheet at the secondary transfer nip.

  The scanner unit 300 reads the image information of the document placed on the contact glass 32 by the reading sensor 36 and sends the read image information to the control unit of the printer unit 100. A control unit (not shown) controls light sources such as laser diodes and LEDs in the optical writing unit 21 of the printer unit 100 based on the image information received from the scanner unit 300, and lasers for Y, M, C, and K. Writing light is emitted to optically scan the photoconductors 20Y, 20M, 20C, and 20K. By this optical scanning, electrostatic latent images are formed on the surfaces of the photoreceptors 20Y, 20M, 20C, and 20K, and the latent images are developed into Y, M, C, and K toner images through a predetermined development process.

  The paper feeding unit 200 includes a paper feeding roller 42 that feeds recording sheets from paper feeding cassettes 44 arranged in multiple stages in the paper bank 43, a separation roller 45 that separates the fed recording sheets and guides them to a paper feeding path 46. A conveyance roller 47 that conveys a recording sheet is provided in a paper feed path 48 of the printer unit 100.

  In addition to the paper feed unit 200, manual paper feed is also possible, and the manual feed tray 51 for manual feed and the recording sheets on the manual feed tray 51 are separated one by one toward the manual feed path 53. A separating roller 52 is also provided. In the printer unit 100, the manual paper feed path 53 joins the paper feed path 48.

  Near the end of the paper feed path 48, a registration roller pair 49 is disposed. The registration roller pair 49 sandwiches the recording sheet conveyed in the paper feed path 48 between the rollers, and then feeds it toward the secondary transfer nip at a predetermined timing.

  In the copying machine according to the embodiment, when copying a color image, an original is set on the original table 30 of the ADF 400, or the ADF 400 is opened and the original is set on the contact glass 32 of the scanner unit 300. Hold the document by closing it. Then, a start switch (not shown) is pressed. Then, when the document is set on the ADF 400, the document is conveyed onto the contact glass 32. Thereafter, the scanner unit 300 starts driving, and the first traveling body 33 and the second traveling body 34 start traveling along the document surface. Then, the light emitted from the light source by the first traveling body 33 is emitted on the original surface, and the obtained reflected light is folded and directed to the second traveling body 34. The folded light is further folded by the mirror of the second traveling body 34 and then incident on the reading sensor 36 through the imaging lens 35. Thereby, the content of the original is read.

  When the printer unit 100 receives image information from the scanner unit 300, the printer unit 100 feeds a recording sheet having a size corresponding to the image information to the paper feed path 48. Along with this, the drive roller 14 is rotationally driven by a drive motor (not shown) to move the intermediate transfer belt 10 endlessly in the clockwise direction in the drawing. At the same time, after starting rotation of the photoconductors 20Y, 20M, 20C, and 20K of the image forming units 18Y, 18M, 18C, and 18K, uniform charging processing, optical writing processing for the photoconductors 20Y, 20M, 20C, and 20K, Perform development processing. The Y, M, C, and K toner images formed on the surfaces of the photoconductors 20Y, 20M, 20C, and 20K by these processes are sequentially overlapped at the Y, M, C, and K primary transfer nips to be intermediate. Primary transfer is performed on the transfer belt 10 to form a four-color superimposed toner image.

  In the paper feeding unit 200, one of the paper feeding rollers 42 is selectively rotated according to the recording sheet size, and the recording sheet is sent out from one of the three paper feeding cassettes 44. The fed recording sheets are separated one by one by the separation roller 45, introduced into the paper feed path 46, and then sent to the paper feed path 48 in the printer unit 100 via the conveyance roller 47. When the manual feed tray 51 is used, the paper feed roller of the tray is driven to rotate, and the recording sheet on the tray is fed to the manual paper feed path 53 while being separated by the separation roller 52 and is fed to the end of the paper feed path 48. To the vicinity. In the vicinity of the end of the paper feed path 48, the recording sheet stops by abutting the leading edge against the registration roller pair 49. Thereafter, when the registration roller pair 49 is rotationally driven at a timing that can be synchronized with the four-color superimposed toner image on the intermediate transfer belt 10, the registration roller pair 49 is fed into the secondary transfer nip and is in close contact with the four-color superimposed toner image on the belt. . Then, the secondary transfer is performed collectively on the recording sheet due to the influence of the nip pressure and the transfer electric field.

The recording sheet onto which the four-color superimposed toner image has been secondarily transferred at the secondary transfer nip is fed into the fixing device 25 by the paper transport belt 22. When the fixing device 25 is sandwiched between the fixing nip between the pressure roller 27 and the fixing belt 26, the four-color superimposed toner image is fixed on the surface by pressure or heat treatment. The recording sheet on which the color image is formed in this manner is stacked on a discharge tray 57 outside the apparatus via a discharge roller pair 56.
If an image is also formed on the other side of the recording sheet, the recording sheet is discharged from the fixing device 25 and then sent to the sheet reversing device 57 by the path switching by the switching claw 55. Then, after being turned upside down, it is returned to the registration roller pair 49 again, and then goes through the secondary transfer nip and the fixing device 25 again.

  After passing through the secondary transfer nip, the belt cleaning device 17 abuts on the surface of the intermediate transfer belt 10 before entering the Y primary transfer nip where the primary transfer process is the most upstream of the four colors. ing. Residual toner remaining on the intermediate transfer belt 10 after image transfer is removed by the belt cleaning device 17 to prepare for re-image formation by the tandem image forming device 20.

  In addition, the copying machine transfers the registration roller pair 49, the secondary transfer device including the secondary transfer roller 24, the sheet conveying belt 22, the fixing device 25, the switching claw 55, the discharge roller pair 56, the sheet reversing device 57, and the like. A drawer unit 500 in which a paper transport related unit is stored is provided.

FIG. 2 is a perspective view of the copying machine showing a state when the drawer unit is pulled out.
As shown in FIG. 2, the drawer unit 500 includes a registration roller pair 49, a secondary transfer device including a secondary transfer roller 24, a sheet conveying belt 22, a fixing device 25, a switching claw 55, a discharge roller pair 56, a sheet reversal. The printer unit 100 is slidable in the front-rear direction by a right slide rail 501 and a left slide rail (not shown) provided on a housing 550 as a holding body that holds the device 57 and the like. The recording sheet conveyance path is exposed by pulling out the drawer unit 500. The housing 550 includes a drawer unit front plate 504, a drawer unit rear plate (not shown), and a plurality of stays (not shown) that connect the drawer unit rear plate 504 and the like.

  When the drawer unit 500 is set in the main body 100, as shown in FIGS. 3 and 4, the fitting holes 504a and 504b provided in the drawer unit front side plate 504 and the fitting pins 101a and 101b provided in the main body front side plate 102 are provided. Are fitted, and similarly, a fitting hole (not shown) provided in the drawer unit rear side plate 505 and a fitting pin (not shown) provided in the main body rear side plate 103 are fitted. The Further, the positioning of the drawer unit 500 in the set direction is performed by abutting against the fitting pins 101a and 101b provided on the front plate 102 on the main body and the stepped portions of the fitting pins provided on the rear plate on the main body.

Next, the secondary transfer unit 350 including the secondary transfer roller 24 will be described.
FIG. 5 is a perspective view showing the rear side of the secondary transfer unit 350, and FIG. 6 is a perspective view showing the front side of the secondary transfer unit 350.
As shown in FIGS. 5 and 6, the secondary transfer unit 350 includes a front frame 350a, a rear frame 350b, and a stay 360 screwed thereto. The secondary transfer roller 24 is rotatably attached to the front holding member 354a and the rear holding member 354b. The front holding member 354a is rotatably attached to the front frame 350a, and the rear holding member 354b is rotatably attached to the rear frame 350b. Spring receivers 354a1 and 354b1 are provided at the ends of the front holding member 354a and the rear holding member 354b. One end of each of the springs 351a and 351b is hooked on the spring receivers 354a1 and 354b1 of the holding members 354a and 354b, and the other end is hooked on the stay 360 to urge the holding members 354a and 354b in the direction of arrow A in the figure. .

  As shown in FIG. 5, a transfer input gear 314 is fixed to the rear end portion of the shaft of the secondary transfer roller 24. The transfer input gear 314 is rotatably attached to the rear holding member 354b. The transferred idler gear 352 is engaged. The transfer idler gear 352 meshes with the joint gear 353 a of the joint member 353. The joint member 353 is fixed to a rear end portion of a rotary shaft 353c (see FIG. 17) rotatably supported by the front frame 350a and the rear frame 350b, and has inner teeth formed on the inner peripheral surface. A spline female portion 353b is provided. The spline female portion 353b is fitted to a spline male portion (not shown) provided with external teeth provided on the apparatus main body side. As a result, the driving force of a transfer drive motor (not shown) provided on the apparatus main body side is 2 through the spline joint portion (configured by the spline female portion 353b and the spline male portion), the transfer idler gear 352, and the transfer input gear 314. The secondary transfer roller 24 is driven to rotate by being transmitted to the secondary transfer roller 24.

  The rear frame 350b is provided with tapered rear positioning holes 358a and 358b for positioning on the transfer unit rear plate 602 (see FIG. 15). Tapered front positioning holes 357a and 357b for positioning on the side plates are provided.

  Also, opposite roller members 312 and 313 are attached to both ends of the shaft of the secondary transfer roller 24 and contact with a secondary transfer roller push-down cam (not shown) arranged coaxially with the secondary transfer counter roller 16. Yes. When a gradation pattern or the like for adjusting the image density is formed on the intermediate transfer belt, the secondary transfer roller 24 is pushed down by a secondary transfer roller push-down cam (not shown) so that the secondary transfer roller 24 is primarily intermediate. Separate from the transfer belt. As a result, it is possible to prevent the gradation pattern from adhering to the secondary transfer roller 24 and to suppress contamination of the secondary transfer roller 24.

FIG. 7 is a front view showing the rear holding member 354b.
As shown in FIG. 7, the rear holding member 354b is rotatably supported by a support shaft 359 attached to the rear frame 350b. A spring receiver 354b1 is provided at the end opposite to the support shaft 359 side and the secondary transfer roller 24, and is urged upward (intermediate transfer belt 10 side) in the figure by the rear spring 351b. Yes. Further, a long hole 354b3 is provided on the opposite side of the support shaft 359 and the secondary transfer roller 24, and the input shaft 361 passes through the long hole 354b3. Release cams 362 are provided on the rear side and the front side of the input shaft 361, respectively. The rear holding member 354b is provided with an abutting portion 354b2 against which the rear release cam 362 abuts.
Although the rear holding member 354b has been described in detail above, the front holding member 354a has the same configuration.

As shown in FIG. 7, when the release cam 362 is separated from the abutting portion 354b2, the secondary transfer roller 24 is applied to the intermediate transfer belt 10 with a predetermined pressure by the urging force of the rear spring 351b. It is in contact. When the drawer unit 500 is pulled out, the input shaft 361 is rotated by a contact / separation driving device described later, and the release cam 362 is rotated clockwise in the drawing. Then, the release cam 362 abuts against the abutting portion 354b2, and the release cam 362 causes the rear holding member 354b to use the support shaft 359 as a fulcrum against the urging force of the rear spring 351b as shown in FIG. The secondary transfer roller 24 is rotated clockwise in the drawing, and the rear side of the secondary transfer roller 24 is separated from the intermediate transfer belt 10. Similarly, the front holding member 354 a is also rotated against the urging force of the front spring 351 a by the front release cam, and the front side of the secondary transfer roller 24 is also separated from the intermediate transfer belt 10. As a result, the secondary transfer roller 24 is separated from the intermediate transfer belt 10. In other words, in this embodiment, the secondary transfer roller 24 is brought into contact with and separated from the intermediate transfer belt 10 by the front and rear holding members 354a and 354b, the front and rear springs 351a and 351b, the release cam 362, and the like. The separation mechanism is configured.
In the present embodiment, the secondary transfer roller 24 is configured to move about 5 to 7 mm from the pressure position shown in FIG. 7 to the retracted position shown in FIG.

  The secondary transfer unit 350 is also provided with a guide plate 241 that guides the recording sheet to the secondary transfer nip, a guide plate 242 that guides the recording sheet that has passed through the secondary transfer nip to the paper transport belt 22, and the like. (See FIG. 9).

Next, fixing of the secondary transfer unit 350 to the drawer unit 500 will be described.
When the drawer unit 500 is pulled out from the main body, the secondary transfer unit 350 is held on the drawer unit so as to be movable to some extent in the left-right direction, the depth direction, and the vertical direction when viewed from the front side of the main body.

FIG. 9 is a perspective view showing the front side of the drawer unit front plate 504 and the secondary transfer unit 350.
As shown in FIG. 9, a transfer unit front side fixing base 510 a for mounting and fixing the front side of the secondary transfer unit 350 is fixed to the drawer unit front side plate 504. The front frame 350a of the secondary transfer unit is placed on the transfer unit front fixing base 510a, and is fixed by a stepped screw 511a.

FIG. 10 is an enlarged plan view showing the periphery of the front-side fixing unit of the drawer unit 500 of the secondary transfer unit 350, and FIG. 11 is a perspective view.
As shown in the figure, the front frame 350a is provided with a flange 321a provided so as to face the transfer unit front fixing base 510a, and a substantially rectangular shape through which a stepped screw 511a passes through the flange 321a. Screw insertion holes 359a are provided. The front side of the secondary transfer unit 350 is attached to the drawer unit 500 by inserting the stepped screw 511a into the screw insertion hole 539a and fastening the stepped screw 511a to the transfer unit front side fixing base 510a.

FIG. 12 is a perspective view showing the drawer unit rear plate 505 and the rear side of the secondary transfer unit 350.
As shown in FIG. 12, the drawer unit rear plate 505 is provided with a transfer unit rear fixing base 510b for mounting and fixing the rear side of the secondary transfer unit 350. The transfer unit rear fixed base 510b is formed by cutting out a part of the drawer unit rear plate 505 made of sheet metal and bending the secondary transfer unit 350 side.

FIG. 13 is an enlarged plan view showing the periphery of the rear fixing portion of the drawer unit 500 of the secondary transfer unit 350, and FIG. 14 is a perspective view.
As shown in the figure, the rear frame 350b is also provided with a flange portion 321b provided so as to face the transfer unit rear-side fixing base 510b, and a stepped screw 511b passes through the flange portion 321b. A rectangular screw insertion hole 359b is provided. The rear side of the secondary transfer unit 350 is attached to the drawer unit 500 by inserting the stepped screw 511b into the screw insertion hole 539b and fastening the stepped screw 511b to the transfer unit rear side fixing base 510b.

  As shown in FIGS. 11 and 14, a predetermined gap is formed between the screw insertion holes 359a and 359b and the stepped portions of the stepped screws 511a and 511b. Thereby, the secondary transfer unit 350 is held on the drawer unit so as to be movable within a predetermined range in the left-right direction and the depth direction when viewed from the front side of the main body. In addition, the secondary transfer unit 350 is attached to the drawer unit 500 with a gap between the heads of the stepped screws 511a and 511b and the flanges 321a and 321b. Accordingly, the secondary transfer unit 350 is held by the drawer unit 500 so as to be movable within a predetermined range in the vertical direction when viewed from the front side of the main body on the drawer unit. In this embodiment, the left-right direction can be moved by 1 mm to the left and right, the depth direction can be moved by 1 mm to the front and back, and the vertical direction can be moved 2-7 mm upward.

Next, positioning of the secondary transfer unit 350 with respect to the transfer unit 600 will be described.
15 is a perspective view showing the transfer unit rear side plate 602 of the transfer unit 600, and FIG. 16 is a perspective view showing the transfer unit front side plate 601 of the transfer unit 600.
As shown in FIG. 15, rear positioning protrusions 612 a and 612 b are provided on the surface of the transfer unit rear side plate 602 facing the transfer unit front side plate 601. Also, as shown in FIG. 16, front positioning protrusions 611a and 611b are provided on the surface of the transfer unit front plate 601 opposite to the side facing the transfer unit rear plate 602. Further, as shown in FIGS. 15 and 16, the positioning protrusions 611a, 611b, 612a, 612b are tapered.

  When the drawer unit 500 is mounted on the apparatus main body, the rear positioning protrusions 612a and 612b of the transfer unit rear plate 602 are rear positioning holes 358a and 358b provided in the rear frame 350b shown in FIG. Inserted into. The rear positioning holes 358a and 358b are mortar-shaped taper holes whose diameters increase as they go later, and the rear positioning protrusions 612a and 612b are tapered, so that the secondary transfer unit Even if the rear side of 350 is slightly deviated from the prescribed position, the tips of the rear positioning protrusions 612a and 612b can be reliably inserted into the rear positioning holes 358a and 358b. Then, the rear positioning protrusions 612a and 612b of the transfer unit 600 are fitted into the rear positioning holes 358a and 358b of the secondary transfer unit 350, so that the rear side of the secondary transfer unit 350 is positioned as shown in FIG. The transfer unit 600 is positioned.

  Further, the front positioning protrusions 611a and 611b of the transfer unit front plate 601 are inserted into the front positioning holes 357a and 357b provided in the front frame 350a shown in FIG. The front positioning holes 357a and 357b are also mortar-shaped taper holes whose diameters increase as they go later, and the front positioning protrusions 611a and 611b also have a tapered shape. Even if the front side is slightly deviated from the specified position, the front end of the front positioning protrusions 611a and 611b can be reliably inserted into the front positioning holes 357a and 357b. Then, the front side positioning protrusions 611a and 611b of the transfer unit 600 are fitted into the front side positioning holes 357a and 357b of the secondary transfer unit 350, so that the front side of the secondary transfer unit 350 is transferred as shown in FIG. Positioned in unit 600.

  As shown in FIG. 17, the front side and the rear side of the secondary transfer unit 350 are positioned on the transfer unit 600, whereby the secondary transfer unit 350 is positioned on the transfer unit 600, and the secondary transfer roller 24 is defined. It can be brought into contact with the intermediate transfer belt 10 at a position, and good secondary transfer properties can be ensured.

  A structure in which the secondary transfer unit 350 is fixed to the drawer unit 500 and the secondary transfer unit 350 is positioned by positioning the drawer unit 500 on the apparatus body as shown in FIGS. In this case, the accuracy of the contact position of the secondary transfer roller 24 with the intermediate transfer belt 10 is deteriorated due to accumulation of component tolerances, accumulation of mounting errors, and the like. On the other hand, as in the present embodiment, the secondary transfer unit 350 is held in the drawer unit 500 so as to be movable at least in the left-right direction and the vertical direction, and the secondary transfer unit 350 is directly positioned on the transfer unit 600. Accumulation of component tolerances and accumulation of mounting errors can be suppressed, and the secondary transfer roller 24 can be brought into contact with the intermediate transfer belt 10 at a specified position with high accuracy.

Next, a release drive mechanism that rotationally drives the release cam 362 shown in FIG. 7 will be described.
FIG. 18 is a schematic configuration diagram of the release drive mechanism 700.
As shown in FIG. 18, the release drive mechanism 700 is provided on the drawer unit front side plate 504, and includes a drive unit 710a and a link mechanism 710b as a drive transmission mechanism.
The drive unit 710a includes a contact / separation drive motor 701, an output shaft 703, and a transmission mechanism (not shown) provided in the case 702 that transmits the driving force of the contact / separation drive motor 701 to the output shaft 703.
The release drive motor 701 is fixed to the case 702 such that a motor shaft (not shown) is parallel to the drawer unit front plate 504. By fixing in this way, the drawer unit 500 can be prevented from being enlarged in the pull-out direction compared to the case where the motor shaft of the release drive motor 701 is fixed so as to be orthogonal to the drawer unit front plate. Can do.

  The drive transmission mechanism (not shown) housed in the case 702 has a worm gear, and the helical teeth of the worm gear are fixed to the motor shaft. The rotating shaft of the screw gear of the worm gear is housed in the case 702 so that it is perpendicular to the drawer unit front plate 504. A driven gear (not shown) is provided coaxially with the screw gear of the worm gear. Then, the driven gear passes through a plurality of idler gears and is output to an output shaft 703 protruding from the case 702.

  Drive transmission from the output shaft 703 to the input shaft 361 is performed by the link mechanism 710b. The link mechanism 710b includes an output link member 711, a connecting link member 712, and an input link member 713. One end of the output link member 711 is fixed to the output shaft 703, and the other end is provided with an output protrusion 711a. Specifically, the end of the output shaft 703 has a D-shaped cross section, and a D-shaped fitting hole is formed at one end of the output link member 711 and is fitted into one end of the output shaft 703. The E ring 714 is attached to the output shaft 703 so that the output link member 711 does not come out of the output shaft 703. One end of a connecting link member 712 is rotatably attached to the output projection 711a of the output link member 711. An elongated hole 712a is formed at the other end of the connecting link member 712, and an input projection 713a provided at one end of the input link member 713 is fitted into the elongated hole 712a. Also, the end of the input shaft 361 has a D-shaped cross section, and a D-shaped fitting hole formed at the other end of the input link member is fitted into one end of the input shaft 361 to input the E-ring 714. It is attached to the shaft 361 so that the input link member does not come out of the input shaft.

  By using the link mechanism 710b for drive transmission from the output shaft 703 to the input shaft 361, a plate material can be used as each link member, and the drawer unit 500 is larger in the pull-out direction than in the case of driving transmission by gears. Can be suppressed.

FIG. 19 is a schematic configuration diagram illustrating a main part of the main body rear side plate 103 of the apparatus main body, and FIG. 20 is a perspective view.
A rear end portion of the output shaft 703 protrudes from the drawer unit rear plate 505, and a fixing member 730 for fixing the drawer unit 500 to the apparatus main body is attached to the end portion. Protrusions 731 a and 731 b extending in the normal direction of the output shaft 703 are provided on the fixing member 730 with an interval of 180 ° in the rotation direction of the output shaft 703.

  A unit fixing portion 110 is provided directly below the through hole 103a through which a spline male portion (not shown) that fits with the spline female portion 353b of the secondary transfer unit 350 of the main body rear side plate 103 passes. The unit fixing part 110 fixes the drawer unit 500 by the contact of the notches 111a and 111b for inserting the protrusions 731a and 731b of the fixing member 730 and the protrusions 731a and 731b of the fixing member 730. Fixed surfaces 113a and 113b and guide portions 112a and 112b for guiding the protrusions 731a and 731b to the fixed surfaces 113a and 113b are provided. The guide portions 112a and 112b are tapered surfaces inclined to the front side. Further, the surface adjacent to the fixed surface on the side opposite to the guide portions 112a and 112b is also a tapered surface. For example, when the drawer unit 500 is pulled out, the output shaft 703 rotates by touching the link member or the like, and the protrusions 731a and 731b may not be completely positioned in the notches 111a and 111b. is there. However, by providing the tapered surface, even if the drawer unit 500 is pulled out in such a state, the protruding portions 731a and 731b can be guided to the notches 111a and 111b by the tapered surface, and the drawer unit 500 can be pulled out. it can.

  When the drawer unit 500 is attached to the apparatus main body and the drawer unit 500 is fixed to the apparatus main body, the protrusions 731a and 731b of the fixing member 730 come into contact with the fixed surfaces 113a and 113b, and the drawer unit 500 Is positioned and fixed in the pull-out direction (front-rear direction). Further, the protrusions 731a and 731b of the fixing member 730 come into contact with the fixed surfaces 113a and 113b, so that the rear frame 350b of the secondary transfer unit 350 hits the transfer unit rear plate 602, and the front frame 350a The secondary transfer unit 350 is positioned in the front-rear direction by abutting against the transfer unit front plate 601.

  The previous FIG. 18 shows a state in which the secondary transfer roller 24 is in contact with the intermediate transfer belt 10 (the release cam 362 is separated from the abutting portion 354b2 as shown in FIG. 7). In this state, the protrusions 731a and 731b of the fixing member 730 are in contact with the fixed surfaces 113a and 113b, and the drawer unit 500 is fixed to the apparatus main body.

  For example, when a paper jam occurs and the drawer unit 500 needs to be pulled out, the release drive motor 701 is driven to rotate the output shaft 703. Then, the protrusions 731a and 731b of the fixing member 730 rotate counterclockwise in FIG. Then, as shown in FIGS. 21 and 22, the driving of the release drive motor 701 stops when the protrusions 731a and 731b reach the positions of the notches 111a and 111b, respectively. Thereby, the drawer unit 500 can be pulled out from the apparatus main body.

  Further, when the release drive motor 701 is driven so that the drawer unit 500 can be pulled out and the output shaft 703 rotates, the output shaft 703 rotates in the clockwise direction in FIG. When the output shaft 703 rotates, as shown in FIG. 18, the output link member 711 rotates clockwise in the drawing, and moves the connecting link member 712 to the right side in the drawing. As the connecting link member 712 moves to the right side in the figure, the input link member 713 rotates together with the input shaft 361 counterclockwise in the figure with the input shaft 361 as a fulcrum. As a result, as described above with reference to FIGS. 7 and 8, the release cam 362 fixed to the input shaft 361 rotates, and the secondary transfer roller 24 moves away from the intermediate transfer belt 10. When the output shaft 703 further rotates, the output link member 711 further pushes the connection link member 712 to the right side in the drawing, further rotates the input link member 713, and the state shown in FIG. The drive of the release drive motor 701 stops. In the state shown in FIG. 23, the protrusions 731a and 731b of the fixing member 730 shown in FIGS. 21 and 22 are at the positions of the notches 111a and 111b, and the secondary transfer roller 24 is in the intermediate transfer state. It is in a separated position completely separated from the belt 10.

  Thus, in the present embodiment, the secondary transfer roller 24 is separated from the intermediate transfer belt 10 in conjunction with the unlocking of the drawer unit 500, so that the drawer unit 500 can be pulled out. The secondary transfer roller 24 can always be separated from the intermediate transfer belt 10. Accordingly, the secondary transfer roller 24 can be prevented from rubbing against the intermediate transfer belt 10 when the drawer unit 500 is pulled out from the apparatus main body, and the surface of the secondary transfer roller 24 and the surface of the intermediate transfer belt 10 are damaged. Generation | occurrence | production can be suppressed.

  Further, since the unlocking motor 701 is automatically driven to release the fixation of the drawer unit 500 and to separate the secondary transfer roller 24 from the intermediate transfer belt 10, the drawer unit 500 can be easily pulled out.

  When the drawer unit 500 is pulled out from the apparatus main body, jammed, etc., and then the drawer unit 500 is stored in the apparatus main body, the release drive motor 701 is driven to rotate again, and the output shaft 703 is further rotated counterclockwise in FIG. Drive to rotate. Then, the protrusions 731a and 731b gradually move toward the rear of the apparatus while being guided by the guides 112a and 112b. Thereby, the drawer unit 500 is further pulled into the apparatus main body. When the protrusions 731a and 731b come into contact with the fixed surfaces 113a and 113b, the release drive motor 701 stops, and the drawer unit 500 is positioned and fixed to the apparatus main body in the front-rear direction.

  Further, when the release drive motor 701 is driven to fix the drawer unit 500 to the apparatus main body and the output shaft 703 rotates, the output shaft 703 rotates clockwise in the drawing in FIG. When the output shaft 703 further rotates clockwise from the state shown in FIG. 23, the link mechanism 710 is in a state where the output link member 711 and the connecting link member 712 are aligned. At this time, the release cam 362 pushes the holding members 354a and 354b most, and the secondary transfer roller 24 is located farthest from the intermediate transfer belt 10. When the output shaft 703 further rotates clockwise in the figure from this state, the output link member 711 moves the connecting link member 712 to the left side in the figure, and the input shaft 361 rotates counterclockwise in the figure. Switches from the direction of rotation to the direction of clockwise rotation. As a result, the pushing of the release cam 362 decreases, and the secondary transfer roller 24 approaches the intermediate transfer belt 10. Then, when returning to the state shown in FIG. 18, the release drive motor 701 stops driving, and the secondary transfer roller 24 contacts the intermediate transfer belt 10 with a predetermined pressure.

  In the present embodiment, by using the link mechanism 710 for driving transmission of the release cam 362, the one-rotation motion of the output shaft 703 can be changed to the swing motion of the release cam 362. As a result, a motor that rotates only in one direction can be used as the release drive motor 701, and the apparatus can be made inexpensive.

  As described above, in this embodiment, the drawer unit 500 is fixed and the secondary transfer roller 24 is brought into contact with the intermediate transfer belt 10, so that the drawer unit 500 is forgotten to be fixed, or the secondary transfer is performed. Forgetting to contact the roller 24 with the intermediate transfer belt 10 does not occur, and the attaching operation of the drawer unit 500 can be easily performed.

  Further, when a drive motor or the like for driving the release cam 362 is provided in the apparatus main body, it is necessary to provide a joint portion or the like. However, by providing the drive unit 710 a for driving the release cam 362 in the drawer unit 500, Parts such as the parts are not necessary, and the apparatus can be made inexpensive. Further, when a drive motor or the like for driving the release cam 362 is provided in the apparatus main body, when the joint unit on the drawer unit side and the joint unit on the apparatus side are fitted, the joint units may collide with each other and be damaged. . On the other hand, in this embodiment, providing the drive unit 710a for driving the release cam 362 in the drawer unit 500 can prevent such damage to the members.

  When the output shaft 703 is configured to rotate easily, when the drawer unit 500 is mounted, the projections 731a and 731b of the fixing member 730 are not inserted into the notches 111a and 111b, but the front surface of the fixed surface. Otherwise, the protrusions 731a and 731b may be damaged, or the drawer unit 500 may not be attached. Therefore, in the present embodiment, a worm gear (not shown) having a large reduction ratio and a high torque is used for drive transmission from the release drive motor 701 to the output shaft 703 so that the output shaft 703 cannot be easily rotated. . This prevents the projections 731a and 731b from being damaged and the drawer unit 500 from being attached to the apparatus main body.

  In the present embodiment, the secondary transfer unit 350 is held by the drawer unit 500 so as to be movable at least in the left-right and vertical directions with respect to the drawer unit 500. The secondary transfer unit 350 is positioned on the transfer unit 600, while the drawer unit 500 is positioned on the apparatus main body. Therefore, when the drawer unit 500 is mounted on the apparatus main body, the positional relationship between the input shaft 361 provided in the secondary transfer unit 350 and the output shaft 703 provided in the drawer unit 500 on the drawer unit front plate 504 varies. To do.

  As in the configuration shown in FIG. 27, the hole in which the input projection 713a of the input link member 713 of the connection link member 712 fits is substantially the same diameter as the input projection 713a. In the configuration in which the drive transmission position to the link member 713 does not change, for example, when the position of the input shaft 361 moves downward with respect to the position shown in FIG. 18 and is in the state shown in FIG. When the connection link member overlaps and the connection link member 712 and the input link member 713 are completely overlapped, the output shaft 703 cannot be rotated. Moreover, even if it can rotate, a big stress will be applied to each link member and the durability of the link mechanism 710b will be impaired.

  On the other hand, in the present embodiment, the connecting link member 712 is configured so that the connecting portion of the connecting link member 712 with the input link member 713 is movable by using a hole into which the input projection 713a of the input link member 713 is fitted as a long hole. Has been. Therefore, when the position of the input shaft 361 moves downward with respect to the position shown in FIG. 18 and the state shown in FIG. 23, the input shaft 361 and the connecting link member 712 overlap, and the connecting link member 712 and the input are input. Even when the link member 713 is completely overlapped, the output shaft 703 can be smoothly rotated, and a large stress is applied to each link member to prevent the durability of the link mechanism 710b from being impaired. be able to.

Specific description will be given below with reference to FIG.
FIG. 24A is a view showing a case where the hole into which the input projection 713a of the input link member 713 of the connection link member 712 is fitted is a hole having substantially the same diameter as the input projection 713a. These are figures which show the case where the hole which the input projection part 713a of the input link member 713 in the connection link member 712 fits into a long hole.
The input shaft 361 indicated by the dotted line in FIG. 24 is moved from the predetermined position to the position indicated by the solid line in the drawing, and the output shaft 703 is rotated clockwise in the drawing to enter the state shown in FIG. When the output shaft 703 further rotates clockwise in the figure, the connecting link member 712 tries to move further to the right side in the figure by the output link member 711. As a result, the input link member 713 receives a force to move from the connecting link member 712 to the right side in the figure. When the drawer unit 500 is mounted on the mounting body, the secondary transfer unit 350 is positioned on the transfer unit 600, and the input shaft 361 provided on the secondary transfer unit 350 is hardly moved. Absent. Therefore, in the configuration shown in FIG. 24A, a large stress that causes the input link member 713 to expand is applied. Further, a large stress is applied to the connecting link member 712 and the output link member 711 in the compression direction due to the reaction force of the input link member 713. Further, the output shaft 703 cannot be rotated due to the tension of the input link member 713.

  On the other hand, in this embodiment, when the output shaft 703 rotates clockwise in the figure from the state shown in FIG. 24 and the connecting link member 712 is moved to the right side in the figure by the output link member, FIG. As shown, the input projection 713a of the input link member relatively moves in the elongated hole 712a. Thereby, the force which moves the input link member 712 to the right side in the figure by the connection link member 712 is not added. Therefore, it is possible to prevent a large stress from being applied to the input link member 713. Further, since the input projection 713a of the input link member 713 relatively moves in the elongated hole 712a, a large stress is applied to the connecting link member 712 and the output link member 711 in the compression direction by the reaction force of the input link member 713. There is nothing. Furthermore, the output shaft 703 can be smoothly rotated, and the rotation of the output shaft 703 can be maintained. When the output shaft 703 rotates and the state of FIG. 24, that is, the state where the connecting link member 712 and the input link member 713 are not completely overlapped, the connecting link member 712 moves from the connecting link member 712 to the input link member 713 in the vertical direction in the figure. Power is added. Therefore, thereafter, the input link member 713 can rotate about the input shaft 361 to rotate the input shaft 361.

  In the above description, the connecting link member 712 is provided with a long hole and the input link member 713 is provided with a protrusion. However, the input link member 713 may be provided with a long hole and the connecting link member 712 may be provided with a protrusion.

  In the above description, the release drive motor 701 automatically switches the drawer unit 500 to and from the main body and switches the secondary transfer roller 24 to and from the intermediate transfer belt 10. As shown in FIG. 25, a lever 704 may be provided for manual operation. A lever 704 as a driving means is fixed to the output shaft 703. Further, as shown in FIG. 25, the connection link member 712 is provided on the rear side of the output link member 711 and the input link member 713 so that the lever 704 and the connection link member 712 do not interfere with each other.

  From the state shown in FIG. 25 (a), as shown in FIG. 25 (b), the lever 704 is rotated 90 ° clockwise in the drawing to release the device of the drawer unit 500, and 2 The next transfer roller 24 is separated from the intermediate transfer belt 10. Then, after pulling out the drawer unit 500 to perform jam processing and the like, and mounting the drawer unit 500 on the apparatus main body, the lever 704 is rotated 90 ° counterclockwise from the state shown in FIG. 25B. The drawer unit 500 is fixed to the apparatus main body, and the secondary transfer roller 24 is brought into contact with the intermediate transfer belt 10.

  In this embodiment, drive transmission from the output shaft 703 to the input shaft 361 is performed by the link mechanism 710, but may be performed by meshing a plurality of gears. In the case of meshing with the gear, the configuration shown in FIG. 26 is used, so that even if the position of the input shaft 361 fluctuates slightly with respect to the position of the output shaft 703, a large stress is not applied to the gear, and the drive transmission is performed. It can be performed.

FIG. 26 is a schematic configuration diagram illustrating an example in which drive transmission from the output shaft 703 to the input shaft 361 is performed using gears.
This configuration includes an output gear 811 fixed to the output shaft, an input gear 813 fixed to the input shaft 361, and a connection gear 812 that meshes with the output gear 811 and the input gear 813. The gear shaft 812 a of the connection gear 812 is attached to one end of the arm member 814, and the other end of the arm member 814 is attached to the output shaft 703. Thereby, the connection gear 812 can revolve around the output gear 811 with the output shaft 703 as a fulcrum. The distance L1 from the meshing position D1 between the output gear 811 and the coupling gear 812 to the meshing position D2 between the coupling gear 812 and the input gear 813 is shorter than the diameter L2 of the coupling gear 812.

  As shown in FIG. 26B, when the position of the input shaft 361 fluctuates from the position of the dotted line in the figure to the position of the solid line in the figure, the connection gear 812 moves with the output shaft 703 as a fulcrum, Engagement can be maintained and drive transmission from the output shaft to the input shaft can be performed. Since the distance L1 from the meshing position D1 between the output gear 811 and the coupling gear 812 to the meshing position D2 between the coupling gear 812 and the input gear 813 is shorter than the diameter L2 of the coupling gear 812, the input shaft 361 Even if the position fluctuates in the direction away from the output shaft (right side in the figure), the meshing between the input gear 813 and the connecting gear 812 can be maintained. Further, when the position of the input shaft 361 changes in the direction approaching the output shaft 703 (left side in the figure), the input gear 813 pushes the connecting gear 812 and rotates the arm member counterclockwise in the figure, Change the position of the connecting gear. Thereby, it can suppress that a big stress is added to a tooth | gear in the meshing position of a connection gear and an input gear, and can suppress damage to a gear.

  In the above description, the example in which the driving unit 710a serving as a driving unit for driving the release cam 362 for bringing the secondary transfer roller 24 into and out of contact with the intermediate transfer belt 10 is provided in the drawer unit 500 has been described. A drive unit that rotationally drives the transfer roller 24 may be provided in the drawer unit 500. As a result, the spline joint portion (configured by the spline female portion 353b and the spline male portion) can be eliminated, and the apparatus can be made inexpensive.

What has been described above is an example, and the present invention has a specific effect for each of the following aspects.
(Aspect 1)
A holder such as a housing 550 that holds a transfer device such as a secondary transfer unit 350 that transfers an image on an image carrier such as an intermediate transfer belt 10 to a transfer medium such as a recording sheet, and is drawn out to the image forming apparatus. In the drawer unit 500 configured to be capable of driving the driving unit such as a driving unit 710a that generates a driving force and the driving unit from the output unit such as the output shaft 703 of the driving unit to the input unit such as the input shaft 361 of the transfer device. A plurality of link members that transmit force, and a long hole in any one of the input link member 713 fixed to the input portion of the plurality of link members and the connecting link member 712 connected to the input link member 713 712a is formed, and on the other side, a fitting protrusion 713a that fits into the long hole 712a is formed, and the fitting protrusion 713a is fitted into the long hole 712a, A force link member 713 connects the connection link member 712.
With this configuration, as described in the embodiment, as described with reference to FIG. 24, even if the position of the input unit such as the input shaft 361 varies with respect to the output unit such as the output shaft 703, A large stress can be suppressed from being applied to the link member, and the drive transmission can be maintained.

(Aspect 2)
Further, in the drawer unit 500 described in (Aspect 1), the plurality of link members are transferred by the secondary transfer roller 24 or the like that contacts the image carrier such as the intermediate transfer belt 10 of the transfer device such as the secondary transfer unit 350. The driving force is transmitted to the contact / separation mechanism that contacts and separates the member with respect to the image carrier.
With such a configuration, a transfer member such as the secondary transfer roller 24 can be satisfactorily brought into contact with and separated from an image carrier such as the intermediate transfer belt 10. Further, when the drawer unit is pulled out, the transfer member and the image carrier can be prevented from rubbing, and the transfer member and the image carrier surface can be prevented from being damaged.

(Aspect 3)
In the drawer unit 500 described in (Aspect 1) or (Aspect 2), the plurality of link members include a fixing mechanism that fixes and releases the drawer unit 500 with respect to the apparatus main body (in this embodiment, fixed). The driving force is transmitted to the member 730 and the unit fixing portion 110.
By providing such a configuration, it is possible to prevent the drawer unit from moving within the apparatus main body.

(Aspect 4)
A holder such as a housing 550 that holds a transfer device such as a secondary transfer unit 350 that transfers an image on an image carrier such as an intermediate transfer belt 10 to a transfer medium such as a recording sheet, and is drawn out to the image forming apparatus. In the drawer unit 500 configured to be capable of driving the driving unit such as a driving unit 710a that generates a driving force and the driving unit from the output unit such as the output shaft 703 of the driving unit to the input unit such as the input shaft 361 of the transfer device. A plurality of gears for transmitting force, one of the plurality of gears is an input gear 813 fixed to an input portion such as the input shaft 361, and a gear 812 that meshes with the input gear among the plurality of gears is Was held movable.
With this configuration, as described with reference to FIG. 36, even when the position of the input unit such as the input shaft 361 varies with respect to the output unit such as the output shaft 703, the meshing with the input gear 813 is maintained. And drive transmission can be maintained. Moreover, it can suppress that a big stress is added to a tooth | gear.

(Aspect 5)
In the drawer unit 500 described in (Aspect 4), the plurality of gears are transfer members such as the secondary transfer roller 24 that abut on the image carrier such as the intermediate transfer belt 10 of the transfer device such as the secondary transfer unit 350. The driving force is transmitted to the contact / separation mechanism that contacts and separates the image bearing member from the image carrier.
With such a configuration, a transfer member such as the secondary transfer roller 24 can be satisfactorily brought into contact with and separated from an image carrier such as the intermediate transfer belt 10. Further, when the drawer unit is pulled out, the transfer member and the image carrier can be prevented from rubbing, and the transfer member and the image carrier surface can be prevented from being damaged.

(Aspect 6)
In the drawer unit 500 according to (Aspect 4) or (Aspect 5), the plurality of gears are fixed mechanisms (in this embodiment, for fixing and releasing the drawer unit 500 with respect to the apparatus main body). The driving force is transmitted to the fixing member 730 and the unit fixing portion 110.
By providing such a configuration, it is possible to prevent the drawer unit from moving within the apparatus main body.

(Aspect 7)
Further, in the drawer unit 500 according to any one of (Aspect 1) to (Aspect 6), the transfer device is positioned with respect to a unit including an image carrier provided in the image forming apparatus. The holding body is configured such that the transfer device is held so as to be movable within a predetermined range with respect to the holding body such as the casing 500 at least in a direction other than the drawing direction of the drawer unit 500.
With this configuration, as described in the embodiment, the transfer device such as the secondary transfer unit 350 can be accurately positioned on the unit such as the transfer unit 600.

(Aspect 8)
In the drawer unit 500 described in any one of (Aspect 1) to (Aspect 7), a conveyance mechanism that conveys a transfer medium such as a recording sheet is held.
With such a configuration, as described in the embodiment, it is possible to perform jam processing by pulling out the drawer unit from the apparatus main body.

(Aspect 9)
Also, an image carrier such as the intermediate transfer belt 10, a transfer device such as a secondary transfer unit 350 that transfers an image on the image carrier onto a transfer medium such as a recording sheet, In the image forming apparatus including the drawer unit 500 configured to be pulled out, the drawer unit 500 according to any one of the above (Aspect 1) to (Aspect 6) is used as the drawer unit.
With such a configuration, it is possible to prevent the transmission mechanism that transmits the driving force to the transfer device such as the secondary transfer unit from being damaged.

(Aspect 10)
Also, an image carrier such as the intermediate transfer belt 10, a transfer device such as a secondary transfer unit 350 that transfers an image on the image carrier onto a transfer medium such as a recording sheet, When the drawer unit 500 described in the above (Aspect 2) or (Aspect 5) is used as the drawer unit and the drawer unit is pulled out from the apparatus main body in the image forming apparatus including the drawer unit 500 configured to be pulled out. The transfer member is automatically separated from the image carrier.
By providing such a configuration, as described in the embodiment, when the drawer unit is pulled out, it is possible to suppress the rubbing between the transfer member and the image carrier, and to prevent damage to the surface of the transfer member or the image carrier. can do.

10: intermediate transfer belt 24: secondary transfer roller 102: main body front plate 103: rear side plate 110: unit fixing portion 321a: collar portion 321b: collar portion 350: secondary transfer unit 350a: front frame 350b: rear frame 351a : Front side spring 351b: rear side spring 354a: front side holding member 354b: rear side holding member 354b2: butting portion 357a, 357b: front side positioning hole 358a, 358b: rear side positioning hole 359: support shaft 360: stay 361: input shaft 362: Release cam 500: Drawer unit 504: Drawer unit front side plate 501 Right slide rail 505: Drawer unit rear side plate 510a: Transfer unit front side fixed base 510b: Transfer unit rear side fixed base 511a, 511b: Stepped screws 539a, 539b: Screw insertion hole 55 0: Housing 600: Transfer unit 601: Transfer unit front plate 602: Transfer unit rear plates 611a, 611b: Front positioning projections 612a, 612b: Rear positioning projection 700: Release drive mechanism 701: Release drive motor 702: Case 703: Output shaft 704: lever 710a: drive unit 710b: link mechanism 711: output link member 712: connection link member 712a: long hole 713: input link member 713a: input projection 730: fixing member 731a, 731b: projection 811: output Gear 812: Connection gear 812a: Gear shaft 813: Input gear 814: Arm member

JP 2000-227691 A

Claims (10)

In a drawer unit that includes a holding body that holds a transfer device that transfers an image of an image carrier to a transfer medium, and is configured to be drawable to the image forming apparatus.
A driving unit that generates a driving force, and a plurality of link members that transmit the driving force of the driving unit from the output unit of the driving unit to the input unit of the transfer device,
A long hole is formed in one of the input link member fixed to the input portion of the plurality of link members and a connecting link member connected to the input link member, and the other is fitted into the long hole. A drawer unit, wherein the input link member and the connecting link member are connected by forming a fitting protrusion to be fitted and fitting the fitting protrusion into the elongated hole. The drawer unit of claim 1,
The drawer unit, wherein the plurality of link members are configured to transmit a driving force to a contact / separation mechanism that contacts and separates a transfer member that contacts the image carrier of the transfer device with respect to the image carrier. The drawer unit according to claim 1 or 2,
The plurality of link members transmit a driving force to a fixing mechanism that fixes and releases the drawer unit with respect to the apparatus main body. In a drawer unit that includes a holding body that holds a transfer device that transfers an image of an image carrier to a transfer medium, and is configured to be drawable to the image forming apparatus.
A drive unit that generates a drive force; and a plurality of gears that transmit the drive force of the drive unit from the output unit of the drive unit to the input unit of the transfer device;
One of the plurality of gears is an input gear fixed to the input unit, and a gear that meshes with the input gear among the plurality of gears is held movably with respect to a holding body. . The drawer unit of claim 4,
The plurality of gears are configured to transmit a driving force to a contact / separation mechanism that contacts and separates a transfer member that contacts the image carrier of the transfer device with respect to the image carrier. The drawer unit according to claim 4 or 5,
The plurality of gears transmit a driving force to a fixing mechanism that fixes and releases the drawer unit with respect to the apparatus main body. The drawer unit according to any one of claims 1 to 6,
The transfer device is positioned with respect to a unit provided with an image carrier provided in the image forming apparatus;
A drawer unit, wherein the holder is configured to hold the transfer device movably within a predetermined range with respect to the holder, at least in a direction other than the drawer direction of the drawer unit. The drawer unit according to any one of claims 1 to 7,
A drawer unit characterized by holding a transport mechanism for transporting the transfer medium. An image carrier;
A transfer device for transferring an image of the image carrier to a transfer medium;
In the image forming apparatus comprising the drawer unit configured to hold the transfer device and be configured to be pulled out from the apparatus body.
An image forming apparatus using the drawer unit according to claim 1 as the drawer unit. An image carrier;
A transfer device for transferring an image of the image carrier to a transfer medium;
In the image forming apparatus comprising the drawer unit configured to hold the transfer device and be configured to be pulled out from the apparatus body.
The drawer unit according to claim 2 or 5 is used as the drawer unit.
An image forming apparatus configured to automatically separate the transfer member from the image carrier when the drawer unit is pulled out from the apparatus main body.

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