JP2017053921A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can facilitate a releasing operation by performing release of transmission of a driving force from a rotational driving force transmission mechanism and release of transmission of a driving force from a nip driving force transmission mechanism in a single releasing operation.SOLUTION: An image forming apparatus 100 comprises: a fixing roller pair 30; a rotational driving force transmission mechanism 60 that transmits a driving force for the fixing roller pair 30 to be driven to rotate from a first driving motor 51 to the fixing roller pair 30; a pressing mechanism 40 that applies a nip force to the fixing roller pair 30; a nip driving force transmission mechanism 70 that transmits a driving force from a second driving motor 52 to the pressing mechanism 40; a cover member 100a that is provided openably/closably on one lateral face of an apparatus body; and a releasing mechanism 80 that releases the transmission of the driving force from the rotational driving force transmission mechanism 60 and the nip driving force transmission mechanism 70 in conjunction with the opening operation of the cover member 100a.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including a pair of conveying rollers that convey a sheet and a driving force transmission mechanism that transmits a driving force to the pair of conveying rollers.

  2. Description of the Related Art Conventionally, an image forming apparatus is known that includes a pair of conveying rollers such as a pair of fixing rollers that are arranged in an apparatus main body and nip and convey a sheet (sheet). In such an image forming apparatus, a rotational driving force transmission mechanism that transmits a driving force for rotating the conveying roller pair from the driving source to the conveying roller pair, and a nip force on the conveying roller pair by pressing the conveying roller pair. And a nip driving force transmission mechanism for transmitting a driving force from the driving source to the pressing mechanism.

  By the way, when a paper jam occurs in the transport roller pair or when the transport roller pair is removed from the apparatus main body, the driving force transmission of the rotational driving force transmission mechanism is canceled or the driving force transmission of the nip driving force transmission mechanism is performed. It is necessary to cancel.

  An image forming apparatus provided with a release mechanism that releases the driving force transmission of the rotational driving force transmission mechanism in conjunction with the opening operation of the cover member is disclosed in, for example, Patent Document 1.

JP 2011-203528 A

  However, in the conventional image forming apparatus, when a paper jam occurs in the conveyance roller pair or when the conveyance roller pair is removed from the apparatus main body, the release of the driving force transmission of the rotational driving force transmission mechanism and the nip driving force transmission mechanism Since it is necessary to cancel the driving force transmission separately, there is a problem that the releasing operation is complicated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to cancel the driving force transmission of the rotational driving force transmission mechanism and to cancel the driving force transmission of the nip driving force transmission mechanism. It is an object of the present invention to provide an image forming apparatus capable of simplifying the release operation by performing the release operation in one release operation.

  In order to achieve the above object, an image forming apparatus according to a first configuration of the present invention includes an apparatus main body, a conveyance roller pair that is arranged in the apparatus main body and conveys the sheet while nipping the sheet, and the conveyance roller pair is rotationally driven. Rotational driving force transmission mechanism for transmitting the driving force for the transfer from the first driving source to the conveying roller pair and the nip force applied to the conveying roller pair by pressing one roller constituting the conveying roller pair against the other roller A nip driving force transmission mechanism for transmitting a driving force from the second driving source to the pressing mechanism, a cover member that can be opened and closed on one side of the apparatus main body, and an opening operation of the cover member. And a release mechanism for releasing the driving force transmission of the rotational driving force transmission mechanism and the nip driving force transmission mechanism.

  According to the first configuration of the present invention, the release mechanism that releases the driving force transmission of the rotational driving force transmission mechanism and the nip driving force transmission mechanism is provided. Thus, for example, when a paper jam occurs in the transport roller pair or when the transport roller pair is removed from the apparatus main body, the driving force transmission cancellation and the nip of the rotational driving force transmission mechanism are performed by operating one release mechanism. Since it is possible to both cancel the driving force transmission of the driving force transmission mechanism, the releasing operation can be simplified.

  The release mechanism releases the driving force transmission of the rotation driving force transmission mechanism and the nip driving force transmission mechanism in conjunction with the opening operation of the cover member. As a result, the two driving force transmissions can be released simply by opening the cover member, so that the release operation can be simplified.

1 is a cross-sectional view schematically showing the structure of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a structure of a fixing roller pair and a pressing mechanism of a fixing device of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a structure of a fixing roller pair and a pressing mechanism of a fixing device of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing a structure around a rotational driving force transmission mechanism, a nip driving force transmission mechanism, and a release mechanism of an image forming apparatus according to an embodiment of the present invention from one side of a frame. FIG. 3 is a perspective view showing the structure around the rotational driving force transmission mechanism, the nip driving force transmission mechanism, and the release mechanism of the image forming apparatus according to the embodiment of the present invention from the other surface side of the frame. FIG. 3 is an exploded view illustrating a structure of a first transmission device of the image forming apparatus according to the embodiment of the present invention. FIG. 2 is a diagram illustrating a structure of a first transmission device of an image forming apparatus according to an embodiment of the present invention, and is a diagram illustrating a state where an input gear and a connecting member are engaged. FIG. 2 is a diagram illustrating a structure of a first transmission device of an image forming apparatus according to an embodiment of the present invention, and is a diagram illustrating a state where an input gear and a connecting member are not engaged. FIG. 6 is a diagram illustrating a structure around a second transmission device of an image forming apparatus according to an embodiment of the present invention, in which a coupling portion is moved leftward (inside the apparatus main body) by a biasing force of a third biasing member. It is the figure which showed the state. FIG. 4 is a diagram illustrating a structure around a second transmission device of an image forming apparatus according to an embodiment of the present invention, in which an input gear of the second transmission device is moved rightward (outside the apparatus main body) by an abutment piece. FIG. FIG. 3 is a diagram illustrating a structure around a release mechanism of an image forming apparatus according to an embodiment of the present invention from the other side of a frame. 1 is a perspective view illustrating a structure of a release mechanism of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing a structure around a contact piece of an image forming apparatus according to an embodiment of the present invention from one side of a frame.

  Embodiments of the present invention will be described below with reference to the drawings.

  An image forming apparatus 100 including a fixing device 13 according to an embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the image forming apparatus 100 (here, a color printer) includes four photosensitive drums (image carriers) 1a, 1b, 1c, and 1d corresponding to four different colors (yellow, cyan, magenta, and black). This is a quadruple tandem type color printer that performs image formation in parallel.

  In the apparatus main body of the image forming apparatus 100, four image forming sections Pa, Pb, Pc, and Pd are sequentially arranged from the left side in FIG. These image forming portions Pa to Pd are provided corresponding to images of four different colors (yellow, cyan, magenta, and black), and yellow, cyan, magenta are respectively obtained by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  These image forming portions Pa to Pd are provided with photosensitive drums 1a to 1d for carrying visible images (toner images) of the respective colors, and further, an intermediate transfer belt that rotates counterclockwise in FIG. 8 is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on the photosensitive drums 1a to 1d are sequentially transferred onto the intermediate transfer belt 8 that moves while contacting the photosensitive drums 1a to 1d, and then the paper ( The sheet is transferred onto the sheet P at a time, and further fixed on a sheet P as an example of a recording medium in the fixing device 13 and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d clockwise in FIG.

  The paper P onto which the toner image is transferred is housed in a paper cassette 16 at the lower part of the apparatus, and is conveyed to the secondary transfer roller 9 via the paper feed roller 12a and the registration roller pair 12b. A sheet made of dielectric resin is used for the intermediate transfer belt 8, and a (seamless) belt having no seam is mainly used. The intermediate transfer belt 8 and the secondary transfer roller 9 are rotationally driven at the same linear speed as the photosensitive drums 1a to 1d by a belt drive motor (not shown). Further, a blade-like belt cleaner 17 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed on the downstream side of the secondary transfer roller 9.

  Next, the image forming units Pa to Pd will be described. Around the photosensitive drums 1a to 1d disposed rotatably, there are charging devices 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d, and the photosensitive drums 1a to 1d. Exposure unit 5 that performs exposure based on image data, development units 3a, 3b, 3c, and 3d that develop electrostatic latent images formed on the photosensitive drums 1a to 1d with toner, and photosensitive drums 1a to 1d Are provided with cleaning devices 7a, 7b, 7c and 7d for collecting and removing the developer (toner) remaining after the transfer of the toner image.

  When image data is inputted from a host device such as a personal computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the charging devices 2a to 2d, and then light is irradiated by the exposure unit 5 based on the image data. The electrostatic latent images corresponding to the image data are formed on the respective photosensitive drums 1a to 1d. Each of the developing units 3a to 3d includes a developing roller disposed so as to face the photosensitive drums 1a to 1d, and each of the developing units 3a to 3d is filled with a predetermined amount of a two-component developer containing toners of yellow, cyan, magenta, and black.

  In addition, when the ratio of the toner in the two-component developer filled in each developing unit 3a to 3d is less than a predetermined value due to the formation of a toner image described later, each developing unit 3a to 3d is transferred from the toner container 4a to 4d. Toner is replenished. This toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached to form a toner image corresponding to the electrostatic latent image formed by exposure of the exposure unit 5. Is done.

  Then, the primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and yellow, cyan, magenta, and the like on the photosensitive drums 1a to 1d. A black toner image is primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning devices 7a to 7d in preparation for the subsequent formation of a new electrostatic latent image.

  The intermediate transfer belt 8 is stretched over a driven roller 10 and a driving roller 11, and when the intermediate transfer belt 8 starts to rotate counterclockwise as the driving roller 11 is rotated by the belt driving motor, the sheet P is registered. It is conveyed from the roller pair 12b to the nip portion (secondary transfer nip portion) between the secondary transfer roller 9 and the intermediate transfer belt 8 provided adjacent to the intermediate transfer belt 8 at a predetermined timing. A full-color image is secondarily transferred to the image. The sheet P on which the toner image is transferred is conveyed to the fixing device 13.

  The sheet P conveyed to the fixing device 13 is fed by a fixing nip portion N (see FIG. 2) of the fixing roller pair 30 including a heating roller (heating rotator) 31 and a pressure roller (pressure rotator) 32. When being conveyed, the toner image is fixed on the surface of the paper P by being heated and pressurized to form a predetermined full-color image. The sheet P on which the full-color image is formed is distributed in the conveying direction by the branching member 21 arranged in the branching portion of the sheet conveying path 18 through the conveying roller pair 15 and is sent as it is (or sent to the duplex conveying path 22 to both sides. After being copied), the sheet is discharged to the discharge tray 20 via the discharge roller pair 19. The fixing roller pair 30 is an example of the “conveying roller pair” in the present invention.

  Specifically, the sheet conveyance path 18 is bifurcated into a left and right fork on the downstream side of the conveyance roller pair 15, and one path (a path branched in the left direction in FIG. 1) communicates with the discharge tray 20. ing. The other path (the path branching rightward in FIG. 1) is configured to communicate with the double-sided conveyance path 22. When images are formed on both sides of the paper P, a part of the paper P that has passed through the fixing device 13 is once protruded from the discharge roller pair 19 to the outside of the device.

  Thereafter, by rotating the discharge roller pair 19 in the reverse direction and swinging the branch member 21 substantially horizontally, the paper P is guided to the double-sided conveyance path 22 along the upper surface of the branch member 21 and the image surface is reversed. Then, it is conveyed again to the secondary transfer roller 9. Then, after the next image formed on the intermediate transfer belt 8 is transferred to the surface of the paper P where the image is not formed by the secondary transfer roller 9 and conveyed to the fixing device 13 to fix the toner image, It is discharged to the discharge tray 20.

  As shown in FIGS. 2 and 3, the fixing device 13 includes a fixing roller pair 30 including a heating roller 31 and a pressure roller 32, and a pressing mechanism 40 that applies a nip force to the fixing roller pair 30. It has.

  The heating roller 31 is a fluorine-based material such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having excellent releasability on a cylindrical metal core made of metal such as aluminum or iron having excellent heat conductivity. A so-called hard roller coated with resin is used, and a heat source such as a halogen heater (not shown) is provided inside the cored bar. Further, an input gear 31 a to which a rotational driving force is input is provided at one end portion of the heating roller 31.

  In the pressure roller 32, an elastic layer such as silicon rubber is formed on a cylindrical base material made of synthetic resin, metal or other material, and the surface of the elastic layer is excellent in releasability such as fluororesin. The one covered with resin is used.

  The heating roller 31 and the pressure roller 32 are arranged so as to be in pressure contact with each other at a predetermined pressure and in parallel. The sheet P conveyed to the fixing nip N between the heating roller 31 and the pressure roller 32 is heated and pressed to melt and fix the powdered toner.

  The pressing mechanism 40 is provided at at least one end of the pressure roller 32. The pressing mechanism 40 includes a bearing member 41 that rotatably supports the rotating shaft 32a of the pressure roller 32, a pressed piece 42 that is disposed at a predetermined interval from the bearing member 41, and a first attachment that includes a compression spring. The biasing member 43 and the eccentric cam 44 are configured.

  The bearing member 41 is formed with a protruding portion 41a that protrudes in a direction orthogonal to the rotation shaft 32a (the right direction in FIG. 2). The pressed piece 42 is formed with a protruding portion 42a that protrudes toward the protruding portion 41a. The first urging member 43 is wound around the protruding portions 41a and 42a, and urges the bearing member 41 and the pressed piece 42 in a direction away from each other. The eccentric cam 44 presses the pressed piece 42 toward the bearing member 41. The eccentric cam 44 changes the distance between the pressed piece 42 and the bearing member 41 by rotating about the rotation shaft 44a. When the eccentric cam 44 is disposed at the position shown in FIG. 2, the urging force of the first urging member 43 is maximized, and the nip force of the nip portion N is maximized. On the other hand, when the eccentric cam 44 is disposed at the position shown in FIG. 3, the urging force of the first urging member 43 is minimized, and the nip force of the nip portion N is minimized.

  On one side of the heating roller 31 and the pressure roller 32 in the axial direction (the back side with respect to the paper surface of FIG. 2), as shown in FIGS. 4 and 5, a first drive motor (first drive source) 51, The second drive motor (second drive source) 52, the rotational drive force transmission mechanism 60 that transmits the drive force from the first drive motor 51 to the fixing roller pair 30, and the drive force from the second drive motor 52 to the pressing mechanism 40. A nip driving force transmission mechanism 70 for transmitting, a release mechanism 80, and a sheet metal frame 50 to which these are fixed are provided.

  The first drive motor 51 is fixed to one surface (outer surface) 50 a of the frame 50, and the gear portion 51 a protrudes toward the other surface (inner surface) 50 b through the through hole of the frame 50. .

  The second drive motor 52 is fixed to a sheet metal 53 attached to the one surface 50 a of the frame 50.

  The rotational driving force transmission mechanism 60 is disposed on the other surface 50 b of the frame 50. The rotational driving force transmission mechanism 60 includes an intermediate gear 61 composed of a two-stage gear, an intermediate gear 62 engaged with the intermediate gear 61, and a first transmission device 63 capable of transmitting and releasing the driving force. ing.

  The intermediate gear 61 engages with the gear portion 51a of the first drive motor 51, and is formed integrally with the large diameter portion 61a to which the rotational drive force is input from the first drive motor 51, and the large diameter portion 61a. And a small-diameter portion 61b that engages with.

  The intermediate gear 62 transmits the rotational driving force from the intermediate gear 61 to the first transmission device 63.

  As shown in FIGS. 6 to 8, the first transmission device 63 is engaged with the intermediate gear 62 and receives an input gear 63a to which the rotational driving force is input from the intermediate gear 62, and a connecting member 63b engaged with the input gear 63a. And an output gear 63c that engages with the connecting member 63b and outputs the rotational driving force from the input gear 63a to the input gear 31a (see FIG. 2) of the heating roller 31, and is disposed between the input gear 63a and the connecting member 63b. A second urging member 63d made of a compression spring and a shaft portion 63e to which these members are attached are included.

  The shaft portion 63e is fixed to the other surface 50b of the frame 50, and rotatably supports the input gear 63a, the connecting member 63b, and the output gear 63c. The input gear 63a is provided with a protrusion 63aa, and the output gear 63c is provided with a protrusion 63ca. The connecting member 63b is provided with a protrusion 63ba that engages with the protrusion 63aa and a protrusion 63bb that engages with the protrusion 63ca. A frustoconical portion 63ab is provided on a portion of the input gear 63a opposite to the protruding portion 63aa.

  As will be described later, the input gear 63a is selectively arranged at the position of FIG. 7 and the position of FIG. 8 by the release mechanism 80. In the state where the input gear 63a is disposed at the position shown in FIG. 7, the projection 63aa and the projection 63ba are engaged, and the projection 63bb and the projection 63ca are engaged. The rotational driving force is transmitted to the output gear 63c via the connecting member 63b, and is output from the output gear 63c to the heating roller 31. On the other hand, in the state in which the input gear 63a is disposed at the position shown in FIG. 8, the engagement between the protrusion 63aa and the protrusion 63ba is released, so that the rotational driving force input to the input gear 63a is the output gear 63c. Not transmitted to. Note that, since the connecting member 63b is urged toward the output gear 63c by the second urging member 63d, the protrusion 63bb and the protrusion 63ca are always engaged.

  As shown in FIGS. 4 and 5, the nip driving force transmission mechanism 70 transmits the rotational driving force from the second driving motor 52 to the pressing mechanism 40, and includes a plurality of intermediate gears 71 and intermediate gears 71. And a second transmission device 72 that transmits the rotational driving force to the pressing mechanism 40.

  The plurality of intermediate gears 71 constitute a driving force transmission train that transmits the rotational driving force from the second driving motor 52 to the second transmission device 72.

  As shown in FIGS. 9 and 10, the second transmission device 72 is engaged with the intermediate gear 71 and receives an input gear (upstream transmission member) 72a to which the rotational driving force from the intermediate gear 71 is input, and from the input gear 72a. A third urging member comprising a coupling portion (downstream transmission member) 72b that outputs the rotational driving force of the second urging drive force to the pressing mechanism 40, and a compression spring disposed between the coupling portion 72b and the other surface 50b of the frame 50. 72c and a shaft portion 72d to which these are attached.

  The shaft portion 72d is attached to the frame 50 and the sheet metal 53 via a bearing so as to be movable in the axial direction of the shaft portion 72d, and penetrates the frame 50 and the sheet metal 53.

  The input gear 72a is disposed on the one surface 50a side of the frame 50, is fixed to the shaft portion 72d, and rotates integrally with the shaft portion 72d. The coupling portion 72b is disposed on the other surface 50b side of the frame 50, is fixed to the shaft portion 72d, and rotates integrally with the shaft portion 72d. For this reason, when the input gear 72a rotates, the coupling part 72b also rotates.

  Further, the input gear 72a and the coupling part 72b are integrated with the shaft part 72d and move in the axial direction of the shaft part 72d (the left-right direction in FIG. 9, the direction orthogonal to the movement direction of the release lever 81 described later). And the position shown in FIG. 10 are selectively arranged. In a state where the coupling portion 72b is disposed at the position of FIG. 9 by the urging force of the third urging member 72c, the coupling portion 72b is provided on the rotating shaft 44a (see FIG. 2) of the eccentric cam 44 of the pressing member 40. The rotational driving force input to the input gear 72 a is transmitted to the eccentric cam 44 in order to engage (connect) with the coupling portion (not shown). On the other hand, in the state where the input gear 72a is disposed at the position of FIG. 10 by the abutting piece 92 described later, a coupling (not shown) provided on the coupling portion 72b and the rotating shaft 44a of the eccentric cam 44 of the pressing member 40. Since the engagement (connection) with the portion is released, the rotational driving force input to the input gear 72 a is not transmitted to the eccentric cam 44.

  The release mechanism 80 releases the driving force transmission of the rotational driving force transmission mechanism 60 and the nip driving force transmission mechanism 70 in conjunction with an opening operation of a cover member 100a described later. Specifically, as shown in FIG. 11, the release mechanism 80 is disposed on the other surface 50 b side of the frame 50, and includes a release lever 81 that can reciprocate in the horizontal direction (left-right direction in FIG. 11), and a release lever 81. 11 and a fourth urging member (release spring) 82 made of a compression spring that urges in the right direction in FIG.

  As shown in FIGS. 11 and 12, the release lever 81 includes a storage portion 81a for storing a part of the fourth urging member 82, an opening portion 81b through which the shaft portion of the intermediate gear 62 is inserted, and the first transmission device. 63, the opening portion 81c through which the shaft portion 63e is inserted, the contact portion 81d provided at the end opposite to the storage portion 81a, and the outside (on the one surface 50a side of the frame 50) compared to the other portions. And a protruding inclined portion (inclined portion, protruding portion) 81e that protrudes.

  The openings 81b and 81c are formed to extend in the left-right direction in FIG. 11 so as to allow the release lever 81 to move in the left-right direction in FIG.

  The contact portion 81d is pressed by the cover member 100a in a state where the cover member 100a provided on one side surface of the apparatus main body is closable (the state shown in FIG. 11). When the cover member 100a is closed (the state shown in FIG. 11), the release lever 81 is disposed at a position where the fourth urging member 82 is compressed. On the other hand, when the cover member 100a is opened, the release lever 81 moves from the position in FIG. 11 toward the right (the opening direction of the cover member 100a) by the urging force of the fourth urging member 82.

  The opening 81c is disposed on the side far from the fourth urging member 82, is disposed on the side closer to the guide portion 81ca that guides the shaft portion 63e, and the fourth urging member 82, and is a truncated cone of the input gear 63a. Receiving portion 81cb into which the shape portion 63ab enters. Therefore, in the state where the cover member 100a is closed and the release lever 81 is disposed at the position of FIG. 11, the shaft portion 63e is disposed within the guide portion 81ca, and therefore the first transmission device 63 is in the state of FIG. The rotational driving force input to the input gear 63a is transmitted to the output gear 63c. On the other hand, when the cover member 100a is opened and the release lever 81 is moved to the right from the position of FIG. 11, the truncated cone portion 63ab enters the receiving portion 81cb, so that the first transmission device 63 is in the state of FIG. Thus, the rotational driving force input to the input gear 63a is not transmitted to the output gear 63c.

  The protruding inclined portion 81e has an inclined surface 81ea and protrudes to the one surface 50a side (the back side with respect to the paper surface of FIG. 11) through the opening 50c of the frame 50.

  As shown in FIG. 13, a holding member 91 is fixed to the one surface 50a of the frame 50 in the vicinity of the opening 50c. The holding member 91 rotatably holds the rotation shaft 92a of the contact piece 92.

  A part of the contact piece 92 is disposed at a position facing the opening 50c (position facing the opening 50c), and when the release lever 81 moves in the direction of the cover member 100a (left direction in FIG. 13), The inclined surface 81ea of the protruding inclined portion 81e presses the contact piece 92 in the right direction in FIG.

  The contact piece 92 is formed with an opening 92b (see FIG. 13) having a diameter larger than that of the shaft portion 72d of the second transmission device 72 and through which the shaft portion 72d of the second transmission device 72 is inserted. The contact piece 92 is disposed between the one surface 50a of the frame 50 and the input gear 72a of the second transmission device 72, and the contact piece 92 rotates around the rotation shaft 92a. The input gear 72a moves in the axial direction of the shaft portion 72d.

  In the state where the cover member 100a is closed and the release lever 81 is disposed at the position shown in FIG. 11, the protruding inclined portion 81e does not contact the contact piece 92, so that the coupling portion 72b is moved by the urging force of the third urging member 72c. The rotational driving force input to the input gear 72 a is transmitted to the eccentric cam 44 in the state of being arranged at the position of FIG. On the other hand, when the cover member 100a is opened and the release lever 81 is moved rightward from the position shown in FIG. 11, the inclined surface 81ea of the protruding inclined portion 81e presses the contact piece 92 rightward in FIG. The input gear 72 a is placed at the position of FIG. 10 by the contact piece 92, and the rotational driving force input to the input gear 72 a is not transmitted to the eccentric cam 44.

  In the present embodiment, as described above, the release mechanism 80 that releases the driving force transmission of the rotational driving force transmission mechanism 60 and the nip driving force transmission mechanism 70 is provided. Accordingly, for example, when a paper jam occurs in the fixing roller pair 30 or when the fixing unit including the fixing roller pair 30 and the pressing mechanism 40 is removed from the apparatus main body, the rotation driving is performed by operating one release mechanism 80. Since both the cancellation of the driving force transmission of the force transmission mechanism 60 and the cancellation of the driving force transmission of the nip driving force transmission mechanism 70 can be performed, the releasing operation can be simplified.

  The release mechanism 80 releases the driving force transmission of the rotational driving force transmission mechanism 60 and the nip driving force transmission mechanism 70 in conjunction with the opening operation of the cover member 100a. As a result, the two driving force transmissions can be released simply by opening the cover member 100a, so that the release operation can be simplified.

  Further, as described above, the second transmission device 72 of the nip driving force transmission mechanism 70 transmits the rotational driving force to the pressing mechanism 40 and the input gear 72a to which the rotational driving force from the second driving motor 52 is transmitted. The coupling portion 72b and the shaft portion 72d to which the input gear 72a and the coupling portion 72b are fixed. The input gear 72a moves in the axial direction of the shaft portion 72d. Are connected or disconnected. As a result, the driving force transmission of the nip driving force transmission mechanism 70 can be easily released.

  As described above, the release mechanism 80 includes the release lever 81 and the fourth urging member 82 that urges the release lever 81 toward the cover member 100a. Accordingly, the release lever 81 moves in conjunction with the opening operation of the cover member 100a, and the input gear 72a moves in the axial direction of the shaft portion 72d. Therefore, it is easier to release the driving force transmission of the nip driving force transmission mechanism 70. Can be done.

  Further, as described above, when the release lever 81 moves in the opening direction of the cover member 100a, the contact piece 92 is pressed against the inclined surface 81ea of the protruding inclined portion 81e, and the input gear 72a is moved to the right ( The release lever 81 is moved in the direction orthogonal to the movement direction of the release lever 81. Thereby, even when the moving direction of the release lever 81 and the axial direction of the shaft portion 72d are orthogonal to each other, the input gear 72a can be easily moved in the axial direction of the shaft portion 72d by the movement of the release lever 81. it can.

  Further, as described above, the release mechanism 80 is formed with the protruding inclined portion 81e that protrudes toward the one surface 50a through the opening 50c of the frame 50. Thus, even when the input gear 72a, the rotational driving force transmission mechanism 60, and the release mechanism 80 are arranged on the opposite side across the frame 50, the single release mechanism 80 transmits the rotational driving force. Both cancellation of the driving force transmission of the mechanism 60 and cancellation of the driving force transmission of the nip driving force transmission mechanism 70 can be easily performed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a color printer has been described, the present invention is not limited to this. Needless to say, various image forming apparatuses including a pair of conveying rollers and a driving force transmission mechanism that transmits a driving force to the pair of conveying rollers, such as a monochrome printer, a color copying machine, a monochrome copying machine, a digital multifunction peripheral, and a facsimile machine. The present invention can be applied to.

  In the above-described embodiment, an example in which the fixing roller pair 30 is used as a conveying roller pair that nips and conveys the sheet is shown. However, a conveying roller pair other than the fixing roller pair 30 may be used.

30 Fixing roller pair (conveying roller pair)
40 pressing mechanism 50 frame 50a one side 50b other side 50c opening 51 first drive motor (first drive source)
52 Second drive motor (second drive source)
60 Rotational driving force transmission mechanism 70 Nip driving force transmission mechanism 72a Input gear (upstream transmission member)
72b Coupling part (downstream transmission member)
72d Shaft portion 80 Release mechanism 81 Release lever 81e Protruding inclined portion (inclined portion, protruding portion)
81ea inclined surface 82 4th urging member (release spring)
92 Contact piece 100 Image forming apparatus 100a Cover member P Paper (sheet)

Claims (5)

The device body;
A pair of conveying rollers arranged in the apparatus main body and conveying the sheet in a nip,
A rotational driving force transmission mechanism for transmitting a driving force for rotationally driving the transport roller pair from a first drive source to the transport roller pair;
A pressing mechanism for applying a nip force to the pair of transport rollers by pressing one roller constituting the pair of transport rollers against the other roller;
A nip driving force transmission mechanism that transmits a driving force from a second driving source to the pressing mechanism;
A cover member provided on one side surface of the apparatus main body so as to be openable and closable;
In conjunction with the opening operation of the cover member, a release mechanism that releases the driving force transmission of the rotational driving force transmission mechanism and the nip driving force transmission mechanism;
An image forming apparatus comprising: The nip driving force transmission mechanism includes an upstream transmission member that transmits a rotational driving force from the second driving source, and a downstream transmission member that transmits the rotational driving force from the upstream transmission member to the pressing mechanism. A shaft portion to which the upstream transmission member and the downstream transmission member are fixed,
The image forming apparatus according to claim 1, wherein the downstream transmission member and the pressing mechanism are connected or disconnected as the upstream transmission member moves in the axial direction of the shaft portion.   The release mechanism moves in the opening direction of the cover member in conjunction with the opening operation of the cover member, and also releases a release lever for moving the upstream transmission member in the axial direction of the shaft portion, and the release lever The image forming apparatus according to claim 2, further comprising: a release spring that biases the cover toward the cover member. A contact piece for moving the upstream transmission member in conjunction with the movement of the release lever;
The release lever is formed with an inclined portion that can contact the contact piece,
When the release lever moves in the opening direction of the cover member in conjunction with the opening operation of the cover member, the contact piece is pressed by the inclined portion and the upstream transmission member is moved in the moving direction of the release lever. The image forming apparatus according to claim 3, wherein the image forming apparatus is moved in a direction substantially orthogonal to the image forming apparatus. A frame to which the rotational driving force transmission mechanism and the nip driving force transmission mechanism are attached;
The upstream transmission member of the nip driving force transmission mechanism is disposed on one side of the frame,
The downstream transmission member of the nip driving force transmission mechanism, the rotational driving force transmission mechanism, and the release lever are disposed on the other surface side of the frame,
The release lever is formed with a protrusion that protrudes to the one surface side through the opening of the frame and moves the upstream transmission member in conjunction with the opening operation of the cover member. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus.

Images