Image forming apparatus

Abstract

To provide an image forming apparatus that allows easy removal of a primary transfer unit from an apparatus body.SOLUTION: An image forming apparatus comprises: a separation lever 92 that separates a primary transfer roller for black from a photoreceptor; and a release mechanism that releases connection between a drive-side coupling and a driven-side coupling 104, in conjunction with a user's operation to separate the primary transfer roller for black from the photoreceptor with the use of the separation lever.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus, and more particularly to an image forming apparatus including, for example, a plurality of photosensitive members and a primary transfer unit detachably provided in the apparatus main body. [Background technology]

[0002] An example of a conventional image forming apparatus is disclosed in Patent Document 1. The image forming apparatus of Patent Document 1 includes a belt unit (primary transfer belt) that is stretched over multiple tension members and onto which a toner image on an image carrier is transferred; a transfer device (primary transfer roller) that transfers the toner image from the image carrier (photosensitive member) to the belt; and a displacement device (separation mechanism) that displaces the transfer device between a contact position and a separation position with the image carrier via the belt. The belt unit is detachable through an opening in the housing of the apparatus main body in a direction perpendicular to the axial direction of the tension member. The image forming apparatus also includes an operating lever that operates the displacement device so that the engaging portion of the displacement device and its corresponding engaged portion are detachably engaged with each other in the axial direction of the tension member on the outer side of the housing. The displacement device is displaceable between a first position and a second position. When the displacement device is in the first position, it reaches a contact position with the transfer device, and when the displacement device is in the second position, it reaches a separation position with the transfer device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-85593 Summary of the Invention [Problem to be solved by the invention]

[0004] The primary transfer unit is driven by a rotational driving force transmitted from a drive source provided in the device body, and therefore when the primary transfer unit is attached to the device body, the device body and the primary transfer unit are connected by a coupling. Therefore, if the attachment / detachment direction of the primary transfer unit is perpendicular to the axial direction of the primary transfer roller, etc., it becomes necessary to release this coupling when removing the primary transfer unit from the device body.

[0005] In the technology of Patent Document 1, a control lever is operated to activate a contact / separation mechanism, thereby displacing the primary transfer roller between a contact position (contact position) and a separated position (separation position) with respect to the photosensitive member via the primary transfer belt. However, with the technology of Patent Document 1, when removing the primary transfer unit from the device main body, it is necessary to separately perform the contact / separation operation of the primary transfer roller using the control lever and the operation to release the coupling, which is inconvenient.

[0006] Therefore, a primary object of this disclosure is to provide a novel image forming apparatus.

[0007] Another object of the present disclosure is to provide an image forming apparatus in which the primary transfer unit can be easily removed from the apparatus main body. [Means for solving the problem]

[0008] The first disclosure is an image forming apparatus having a plurality of photosensitive drums and a primary transfer unit that is detachably attached to the apparatus main body, and includes a drive-side coupling provided in the apparatus main body, and a driven-side coupling provided in the primary transfer unit that is connected to the drive-side coupling in a second direction perpendicular to a first direction in which the primary transfer unit is attached and detached, and the primary transfer unit includes a primary transfer belt onto which a toner image is transferred from the plurality of photosensitive drums, a plurality of primary transfer rollers that are arranged to face each of the photosensitive drums across the primary transfer belt, and a separation mechanism that separates the primary transfer rollers from the photosensitive drums, and the separation mechanism is arranged to be able to move back and forth in the first direction and includes a separation lever that separates the black primary transfer roller from the photosensitive drums, and the image forming apparatus is equipped with a release mechanism that releases the connection between the drive-side coupling and the driven-side coupling in conjunction with the user's action of using the separation lever to separate the black primary transfer roller from the photosensitive drum.

[0009] According to the first disclosure, the separation of the black primary transfer roller and the release of the coupling can be performed in a single operation, so the primary transfer unit can be easily removed from the device main body, which is highly convenient.

[0010] The second disclosure is dependent on the first disclosure, and the release mechanism includes a release member that is provided in the primary transfer unit and converts a force that moves the separation lever to the abutment release position into a force in a direction that causes the driven-side coupling to separate from the drive-side coupling, and transmits the force to the driven-side coupling.

[0011] The third disclosure is dependent on the second disclosure, and the release member is provided on the primary transfer unit so as to extend in a first direction, and is rotatable around a rotation axis in a second direction, and is rotatable around a rotation axis in a third direction perpendicular to the first direction and the second direction.

[0012] The fourth disclosure is dependent on the third disclosure, and the release member has a receiving portion formed at one end in the first direction and receiving a force that moves the separation lever to the abutment release position, and a pressing portion formed at the other end in the first direction and pressing the driven side coupling to separate it from the drive side coupling when the receiving portion receives a force accompanying the movement of the separation lever.

[0013] The fifth disclosure is dependent on the second disclosure, and the release member includes a conversion member that is formed in a substantially L-shape and that rotates around a bent portion to convert a force that moves the separation lever to the abutment release position into a force in a direction that moves the driven-side coupling away from the drive-side coupling, and a pressing member that is provided so as to be able to move back and forth in the second direction and that presses the driven-side coupling to separate it from the drive-side coupling when the conversion member receives a force accompanying the movement of the separation lever.

[0014] A sixth disclosure is dependent on any one of the first to fifth disclosures, and the primary transfer unit includes a locking portion that holds the separation lever in a state where the separation lever is in a contact release position. [Effects of the Invention]

[0015] According to this disclosure, the separation of the black primary transfer roller and the release of the coupling can be performed in a single operation, so the primary transfer unit can be easily removed from the device main body, which is highly convenient.

[0016] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments, which proceeds with reference to the drawings. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic cross-sectional view showing an internal structure of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view showing a primary transfer unit provided in the image forming apparatus. [Figure 3] FIG. 2 is a front view showing the primary transfer unit. [Figure 4]FIG. 2 is a rear view showing the primary transfer unit. [Figure 5] FIG. 10 is a front view illustrating the primary transfer unit in a color printing mode, illustrating a mechanism for separating and contacting the primary transfer roller. [Figure 6] FIG. 10 is a front view illustrating the primary transfer unit in a monochrome printing mode, illustrating a mechanism for separating and contacting the primary transfer roller. [Figure 7] FIG. 10 is a front view illustrating the primary transfer unit in a free mode, illustrating a mechanism for separating and contacting the primary transfer roller. [Figure 8] FIG. 4 is a plan view showing the periphery of the separating lever. [Figure 9] FIG. 10 is a rear view showing the release mechanism and its surroundings before the coupling is released. [Figure 10] FIG. 10 is a plan view showing the periphery of the release mechanism before the coupling is released. [Figure 11] FIG. 10 is a perspective view showing the periphery of the release mechanism before the coupling is released. [Figure 12] FIG. 4 is an exploded view showing the release mechanism and its surroundings with the release member removed. [Figure 13] FIG. 4 is a cross-sectional view showing the periphery of the release mechanism before the coupling is released. [Figure 14] FIG. 10 is a rear view showing the release mechanism and its surroundings after the coupling is released. [Figure 15] FIG. 10 is a cross-sectional view showing the periphery of the release mechanism after the coupling is released. [Figure 16] FIG. 10 is a plan view showing the periphery of a release mechanism before the coupling is released in the second embodiment. [Figure 17] FIG. 10 is a perspective view showing a conversion member provided in a release member of a second embodiment. [Figure 18] FIG. 10 is a perspective view showing a pressing member provided in a release member of a second embodiment. [Figure 19] FIG. 10 is a plan view showing the periphery of the release mechanism after the coupling is released in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] [First Example] 1, an image forming apparatus 10 according to an embodiment of the present disclosure is a multifunction peripheral (MFP) having functions such as copying, printing, scanning, and facsimile, and forms multicolor or monochrome images on printing paper by electrophotography. As will be described in detail later, the image forming apparatus 10 is an intermediate transfer type image forming apparatus that primarily transfers a toner image from a plurality of photosensitive drums 36 (an example of a photosensitive body) arranged side by side onto a primary transfer belt 54, and then secondarily transfers the toner image from the primary transfer belt 54 onto printing paper, and includes a primary transfer unit 42 detachably provided in the apparatus main body 12.

[0019] First, a general description will be given of the configuration of the image forming apparatus 10. In this specification, the front (front face) is defined as the surface facing the user's standing position, i.e., the surface on which an operation unit (not shown) is provided, and the front-to-rear direction (depth direction) of the image forming apparatus 10 and its components is defined. The operation unit is provided on the near side of the paper in FIG. 1. The left-to-right direction (horizontal direction) of the image forming apparatus 10 and its components is defined based on the state in which the image forming apparatus 10 is viewed from the user.

[0020] As shown in FIG. 1, the image forming apparatus 10 includes an apparatus main body 12 and an image reading device 14 disposed above the apparatus main body 12. The image reading device 14 is provided with a document placing table 16 formed of a transparent material. A document pressing cover 18 is attached to the upper side of the document placing table 16 via a hinge or the like so as to be able to open and close freely. The document pressing cover 18 is provided with an automatic document feeder (ADF) 24 that automatically feeds documents placed on a document placing tray 20 one by one to an image reading position 22. In addition, an operation unit is provided on the front side of the document placing table 16 for receiving input operations such as printing instructions from a user. The operation unit is appropriately provided with a display such as a touch panel display and various operation buttons, etc.

[0021] The image reading device 14 also includes an image reading unit 26 equipped with a light source, multiple mirrors, an imaging lens, a line sensor, etc. The image reading unit 26 exposes the surface of the document to light, and guides the light reflected from the document surface to the imaging lens via multiple mirrors. The imaging lens then forms an image of the reflected light on the light-receiving elements of the line sensor. The line sensor detects the luminance and chromaticity of the reflected light that forms an image on the light-receiving elements, and generates image data based on the image of the document surface. A CCD (Charge Coupled Device) or a CIS (Contact Image Sensor) is used as the line sensor.

[0022] The device main body 12 is provided with a control unit 28 including a CPU and memory, etc., and an image forming unit 30. The control unit 28 transmits control signals to each part of the image forming device 10 in response to input operations by a user to an operation unit, etc., and causes the image forming device 10 to perform various operations.

[0023] Image forming section 30 includes an exposure device 32, a developing device 34, a photosensitive drum 36, a cleaner unit 38, a charging device 40, a primary transfer unit 42, a secondary transfer unit 44, and a fixing unit 46, and forms an image on print paper transported from a paper feed cassette 48 or a manual paper feed tray 50, and discharges the print paper with the image formed on it to a paper discharge tray 52. Image data used to form an image on the print paper is image data read by image reading section 26 or image data sent from an external computer, etc.

[0024] The image data handled by the image forming apparatus 10 corresponds to four color images: black (K), cyan (C), magenta (M), and yellow (Y). Therefore, four developing devices 34, four photosensitive drums 36, four cleaner units 38, and four charging devices 40 are provided to form four types of latent images corresponding to the four colors, constituting four image stations (also referred to as process units). The four image stations are arranged in a line along the running direction (circumferential direction) of the surface of the primary transfer belt 54, and are arranged in the following order from the downstream side in the running direction of the primary transfer belt 54, i.e., from the side closest to the secondary transfer unit 44: black, cyan, magenta, and yellow. However, the order of the colors can be changed as needed.

[0025] The subscripts K, C, M, and Y attached to the reference numerals indicate that the element is provided for one of the colors, and the subscripts K, C, M, and Y indicate black, cyan, magenta, and yellow, respectively. For example, in FIG. 1, the reference numeral 36K indicates a photosensitive drum for black, and the reference numeral 60K indicates a primary transfer roller for black. However, when it is not necessary to distinguish which color each component is for in the description of each component, the subscripts K, C, M, and Y are omitted and the description is generalized.

[0026] The photosensitive drum 36 is an image carrier having a photosensitive layer formed on the surface of a conductive cylindrical sleeve (substrate). Each photosensitive drum 36 is rotatable around its axis. The charging device 40 charges the surface of the photosensitive drum 36 to a predetermined potential. The exposure device 32 is configured as a laser scanning unit (LSU) equipped with a laser emitter and a reflecting mirror, etc., and exposes the charged surface of the photosensitive drum 36 to light to form an electrostatic latent image on the surface of the photosensitive drum 36 according to image data. The developing device 34 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 36 with four-color (YMCK) toner. The cleaner unit 38 removes toner remaining on the surface of the photosensitive drum 36 after development and image transfer.

[0027] The primary transfer unit 42 includes a primary transfer belt 54, a drive roller 56, a driven roller 58, four primary transfer rollers 60, a pre-transfer roller 62, a contact / separation mechanism 64 (see FIG. 2), and a release mechanism 100 (see FIG. 2), and is disposed above the photosensitive drum 36. The primary transfer unit 42, the primary transfer belt 54, and the primary transfer rollers 60 are also referred to as an intermediate transfer unit, an intermediate transfer belt, and an intermediate transfer roller, respectively.

[0028] The primary transfer belt 54 is an endless belt that is tensioned by a plurality of tension rollers so as to be rotatable in a predetermined rotational direction (counterclockwise in FIG. 1 ), and is disposed so that its outer peripheral surface (bottom surface) is aligned with the plurality of photosensitive drums 36 that are arranged side by side. The plurality of tension rollers include a drive roller 56, a driven roller 58, a pre-transfer roller 62, and a tension roller, and each of these tension rollers is disposed so that its shaft extends in the front-to-rear direction. During image formation, the outer peripheral surface of the primary transfer belt 54 is in contact with the surface of the photosensitive drum 36.

[0029] The drive roller 56 is provided so as to be rotatable about its axis by a drive unit (not shown). A driven coupling 104 (see FIG. 2) is provided at the rear end of the roller shaft of the drive roller 56. This driven coupling 104 is coupled in the front-rear direction (second direction) to a drive coupling 102 (see FIG. 13) provided in the apparatus main body 12, thereby transmitting a rotational drive force from a drive source to the drive roller 56. As the drive roller 56 rotates, the primary transfer belt 54 moves in a predetermined rotational direction. The driven roller 58 rotates in accordance with the rotational movement of the primary transfer belt 54 and applies a constant tension to the primary transfer belt 54 to prevent slack in the primary transfer belt 54. The pre-transfer roller 62 has the function of expanding the width (length in the paper transport direction) of a secondary transfer nip portion (described later), thereby improving transferability.

[0030] The primary transfer rollers 60 are members for transferring (primary transfer) the toner images formed on the corresponding photosensitive drums 36 onto the primary transfer belt 54, and are disposed at positions facing the photosensitive drums 36 of each color across the primary transfer belt 54. When a primary transfer current is supplied to the primary transfer rollers 60, a transfer electric field is formed between the photosensitive drums 36 and the primary transfer belt 54 at the primary transfer position. The toner images formed on the photosensitive drums 36 are transferred to the outer circumferential surface of the primary transfer belt 54 by the action of the transfer electric field formed at this primary transfer position.

[0031] Each of the primary transfer rollers 60 can be displaced in a direction (vertical direction) in which it moves toward or away from the corresponding photosensitive drum 36 by a contact / separation mechanism 64. The primary transfer belt 54 moves toward or away from the photosensitive drum 36 by displacement of the primary transfer rollers 60. Furthermore, the primary transfer unit 42 is provided with a release mechanism 100 for separating the driven-side coupling 104 from the drive-side coupling 102 (i.e., releasing the connection) when the primary transfer unit 42 is removed from the apparatus main body 12. Specific configurations of the contact / separation mechanism 64 and the release mechanism 100 will be described later.

[0032] The secondary transfer unit 44 includes a secondary transfer roller for transferring the toner image formed on the primary transfer belt 54 to a print medium, and is disposed opposite the drive roller 56 across the primary transfer belt 54. When the print paper passes through the secondary transfer nip between the secondary transfer roller and the primary transfer belt 54, the toner image formed on the primary transfer belt 54 is transferred to the print paper.

[0033] The fixing unit 46 includes a heat roller and a pressure roller, and is located above the secondary transfer unit 44. The heat roller is set to a predetermined fixing temperature. When the print paper passes through the nip area (fixing nip) between the heat roller and the pressure roller, the toner image transferred to the print paper is heated and pressed against the print paper, and the toner image is thermally fixed to the print paper.

[0034] Also formed within the device main body 12 is a first paper transport path L1 for sending print paper from the paper feed cassette 48 or manual paper feed tray 50 to the paper output tray 52 via registration rollers 68, secondary transfer unit 44 (secondary transfer nip portion), and fixing unit 46. Also formed is a second paper transport path L2 for returning print paper, when double-sided printing is performed on the print paper, after printing on the front side is completed and the print paper has passed through the fixing unit 46, to the first paper transport path L1 upstream in the paper transport direction of the secondary transfer unit 44. A plurality of transport rollers 66 for applying auxiliary propulsion force to the print paper are appropriately provided in the first paper transport path L1 and the second paper transport path L2.

[0035] Next, a specific description will be given of the configuration of the separation mechanism 64 provided in the primary transfer unit 42. However, in Figures 2 to 7, the primary transfer belt 54 is omitted to make it easier to understand the structure of the primary transfer unit 42. Also, in Figures 5 to 7, a part of the front frame 70 is omitted to make it easier to understand the operation of the separation mechanism 64.

[0036] 2 to 4, the primary transfer unit 42 includes a primary transfer belt 54, a drive roller 56, a driven roller 58, four primary transfer rollers 60, a pre-transfer roller 62, a contact / separation mechanism 64, and a release mechanism 100. These are held in a predetermined arrangement mode directly or indirectly by a front frame 70 and a rear frame 72 (hereinafter collectively referred to as "unit frames 70, 72") that are substantially rectangular plates and extend in the left-right direction (a direction perpendicular to the axial direction of the tension rollers such as the drive roller 56).

[0037] The primary transfer unit 42 is detachably mounted to the apparatus main body 12. In this embodiment, the direction (first direction) for attaching and detaching the primary transfer unit 42 is the left-right direction. A grip 106 is provided at the right end of the unit frames 70, 72. The grip 106 is used when attaching and detaching the primary transfer unit 42 to and from the apparatus main body 12. Although not shown, in this embodiment, when a right door on the right side of the apparatus main body 12 is opened, an access opening is opened and the right end of the primary transfer unit 42 is exposed to the outside. The primary transfer unit 42 can be removed from the apparatus main body 12 by gripping the grip 106 and pulling the primary transfer unit 42 toward the access opening (right side). To remove the primary transfer unit 42, it is necessary to retract the primary transfer roller 60 to the separated position and release the couplings 102, 104, as described below. On the other hand, when attaching the primary transfer unit 42 to the device main body 12, it is advisable to fit the left part of the primary transfer unit 42 into the device main body 12, and then grasp the gripping portion 106 or the like and push the primary transfer unit 42 to the left side to the attachment position.

[0038] The contact / separation mechanism 64 is a mechanism for contacting and separating the primary transfer roller 60 (and therefore the primary transfer belt 54) with and from the photosensitive drum 36. The contact / separation of the primary transfer belt 54 with and from the photosensitive drum 36 is achieved by the primary transfer roller 60 being displaced between a contact position where it presses against the inner circumferential surface of the primary transfer belt 54 to bring the photosensitive drum 36 and the primary transfer belt 54 into contact with each other, and a separation position where it releases the pressure on the primary transfer belt 54 to separate the primary transfer belt 54 from the photosensitive drum 36. In other words, each primary transfer roller 60 is displaceable between a contact position where the photosensitive drum 36 and the primary transfer roller 60 are in contact with each other across the primary transfer belt 54, and a separation position where the primary transfer roller 60 is separated from the photosensitive drum 36.

[0039] In this embodiment, the contact / separation mechanism 64 includes a first contact / separation mechanism 64YMC that is a contact / separation mechanism for color toner, and a second contact / separation mechanism 64K that is a contact / separation mechanism for black toner. As will be described in detail later, the color primary transfer rollers 60Y, 60M, and 60C are displaced in conjunction with each other by operating the first contact / separation mechanism 64YMC using a driving force from the apparatus main body 12 based on instructions from the control unit 28. On the other hand, the black primary transfer roller 60K is displaced independently of the color primary transfer rollers 60Y, 60M, and 60C by operating the second contact / separation mechanism 64K through manual operation by the user.

[0040] For example, in a color printing mode (see FIG. 5) in which a color image is formed, all of the primary transfer rollers 60 are disposed in the contact position, and all of the photosensitive drums 36 are in contact with the primary transfer belt 54. Then, the toner images of each color formed on each photosensitive drum 36 are sequentially transferred onto the primary transfer belt 54 in a superimposed manner, thereby forming a multi-color toner image on the outer circumferential surface of the primary transfer belt 54. Also, in a monochrome printing mode (see FIG. 6) in which a monochrome image is formed, the color primary transfer rollers 60Y, 60M, and 60C are disposed in the separation position, while the black primary transfer roller 60K is disposed in the contact position, and only the black photosensitive drum 36K is in contact with the primary transfer belt 54. Then, a toner image is formed only on the black photosensitive drum 36K, and only the black toner image is transferred onto the outer circumferential surface of the primary transfer belt 54. Furthermore, when the primary transfer unit 42 is attached to or detached from the apparatus main body 12 (see FIG. 7), all of the primary transfer rollers 60 are disposed in the separated position, and all of the photosensitive drums 36 are separated from the primary transfer belt 54. In this embodiment, in the standby mode (when no image is being formed), the color primary transfer rollers 60Y, 60M, and 60C are disposed in the separated position, while the black primary transfer roller 60K remains disposed in the contact position.

[0041] 2 to 4 as well as FIG. 5, the separation / attachment mechanism 64 includes a first separation / attachment mechanism 64YMC and a second separation / attachment mechanism 64K. The first separation / attachment mechanism 64YMC includes collar arm members 76Y, 76M, 76C, a link member 78, and a cam member 80. The collar arm members 76Y, 76M, 76C, the link member 78, and the cam member 80 are pairs of members provided on the front frame 70 side and the rear frame 72 side, respectively.

[0042] The color transfer arm members 76Y, 76M, and 76C are formed in a substantially L-shape, and the color transfer primary transfer rollers 60Y, 60M, and 60C are rotatably supported at one end thereof. Meanwhile, the other end of the color transfer arm members 76Y, 76M, and 76C is formed with pressure receiving portions 84Y, 84M, and 84C that receive pressure from pressing portions 82Y, 82M, and 82C formed on the link member 78. Furthermore, bent portions of the color transfer arm members 76Y, 76M, and 76C are rotatably supported by support protrusions formed on the unit frames 70 and 72. That is, the color transfer arm members 76Y, 76M, and 76C are rotatable about the bent portions, and as the color transfer arm members 76Y, 76M, and 76C rotate (displace), the color transfer primary transfer rollers 60Y, 60M, and 60C move up and down (approach or separate from the photosensitive drum 36). In addition, the color arm members 76Y, 76M, and 76C are provided with biasing members (not shown) such as torsion springs, and the color arm members 76Y, 76M, and 76C are biased in a direction that moves the color primary transfer rollers 60Y, 60M, and 60C downward, i.e., toward the photosensitive drum 36.

[0043] The link member 78 is formed in a generally rectangular plate shape extending in the left-right direction and is provided on the inner surface side of the unit frames 70, 72 (the rear surface side of the front frame 70 and the front surface side of the rear frame 72) so as to be reciprocable in the left-right direction (first direction). In other words, the movement direction of the link member 78 and the attachment / detachment direction of the primary transfer unit 42 are the same direction. The link member 78 is formed with pressing portions 82Y, 82M, and 82C at positions to the right of the pressure-receiving portions 84Y, 84M, and 84C of the color arm members 76Y, 76M, and 76C, respectively, for pressing and displacing the color arm members 76Y, 76M, and 76C. In addition, the link member 78 is formed with a wall portion at a position to the left of a cam member 80, which will be described later, for receiving a pressing force from the cam member 80. Such a link member 78 is movable between an abutment position (see Figure 5) and a disengagement position (see Figure 6), and displaces the color arm members 76Y, 76M, 76C according to the movement position, thereby causing the color primary transfer rollers 60Y, 60M, 60C to come into contact with and separate from the photosensitive drum 36.

[0044] Furthermore, a biasing member 86 such as a tension coil spring is provided at the left end of the link member 78 to bias the link member 78. One end of the biasing member 86 is fixed to the unit frames 70, 72, and the other end of the biasing member 86 is fixed to the link member 78. The link member 78 is biased to the left (towards the abutment position) by this biasing member 86.

[0045] The cam member 80 is a member for pressing the link member 78 to reciprocate, and is attached to both ends of a cam shaft 88, which is rotatably held by the unit frames 70, 72. A drive motor (not shown) is connected to the cam shaft 88, and the drive force of the drive motor rotates the cam shaft 88, thereby rotating the cam member 80. The drive motor is a general-purpose motor such as a stepping motor, and is controlled by the control unit 28. The cam member 80 is, for example, a plate cam, and the distance between its outer circumferential surface and the cam shaft 88 changes depending on the phase (rotation angle) of the cam member 80. The cam member 80 reciprocates the link member 78 between an abutment position and a disengagement position based on instructions from the control unit 28.

[0046] On the other hand, the second separating mechanism 64K includes a black arm member 76K, a second arm member 90, and a separating lever 92. The black arm member 76K, the second arm member 90, and the separating lever 92 are each a pair of members provided on the front frame 70 side and the rear frame 72 side, respectively.

[0047] The black arm member 76K is formed in a substantially L-shape, and the black primary transfer roller 60K is rotatably supported at one end thereof. The other end of the black arm member 76K is connected to the other end of the second arm member 90 via a connecting member 94 such as a wire. The bent portion of the black arm member 76K is rotatably supported by a support protrusion formed on the unit frames 70 and 72. That is, the black arm member 76K is rotatable around the bent portion, and as the black arm member 76K rotates (displaces), the black primary transfer roller 60K moves vertically (approaching or separating from the photosensitive drum 36). The black arm member 76K is provided with a biasing member (not shown) such as a torsion spring, and the black arm member 76K is biased in a direction that moves the black primary transfer roller 60K downward, i.e., toward the photosensitive drum 36.

[0048] The second arm member 90 is formed so as to be slightly bent at its center, and one end (lower end) of the second arm member 90 rotatably supports the pre-transfer roller 62 and the tension roller. Meanwhile, the other end (upper end) of the second arm member 90 is formed with a pressure receiving portion 90a that receives a pressing force from a pressing portion 92c provided on the separation lever 92. The other end of the second arm member 90 is connected to the other end of the black arm member 76K via a connecting member 94. The bent portion of the second arm member 90 is supported so as to be rotatable around the roller axis of the drive roller 56. In other words, the second arm member 90 is rotatable about the bent portion, and as the second arm member 90 rotates (displaces), the black arm member 76K rotates and the pre-transfer roller 62 and the tension roller move in the vertical direction. In addition, the second arm member 90 is provided with a biasing member (not shown) such as a torsion spring, and the second arm member 90 is biased in a direction in which the pre-transfer roller 62 and the tension roller press downward, i.e., in a direction in which they press the primary transfer belt 54.

[0049] As can be clearly seen from FIG. 8 , the separation lever 92 has a round-bar-shaped shaft portion 92a extending in the left-right direction (first direction) and is provided on the unit frames 70, 72 so as to be reciprocable in the left-right direction and rotatable about the axis of the shaft portion 92a. An operating portion 92b is provided at one end (right end) of the shaft portion 92a and is used to operate the separation lever 92, etc. The shape of the operating portion 92b is not particularly limited, but in this embodiment, the operating portion 92b is formed in a rectangular plate shape so that the user can easily rotate and pull (or push) the separation lever 92. Meanwhile, a pressing portion 92c such as a C-ring is provided at the other end (left end) of the shaft portion 92a to press and displace the second arm member 90. Such a separation lever 92 can be moved to an abutment position (see Figure 6) and a release position (see Figure 7), and by displacing the second arm member 90 according to the movement position, the black arm member 76K is rotated to separate the black primary transfer roller 60K from the photosensitive drum 36, and the pre-transfer roller 62 and tension roller are moved up and down.

[0050] The primary transfer unit 42 also includes a locking section 110 that keeps the separation lever 92 in the disengaged position. The locking section 110 prevents the separation lever 92 from returning to the engaged position from the disengaged position by the biasing force of a biasing member provided on the black primary transfer roller 60K or the like. Specifically, as can be clearly seen from FIG. 8 , the locking section 110 includes a guide member 112 provided on the right end of the unit frames 70, 72, and a locking protrusion 92d provided on the shaft 92a of the separation lever 92. The guide member 112 is formed in a cylindrical shape through which the shaft 924a of the separation lever 92 is slidably inserted, and the guide member 112 is formed with a guide groove 114 into which the locking protrusion 92d of the separation lever 92 engages. The guide groove 114 has a sliding groove 114a extending in the left-right direction (first direction), a first locking portion 114b extending from one end (right end) of the sliding groove 114a in the circumferential direction of the guide member 112, and a second locking portion 114c extending from the other end (left end) of the sliding groove 114a in the circumferential direction of the guide member 112. The locking protrusion 92d is fitted into the first locking portion 114b, thereby holding the separation lever 92 in the abutment release position. On the other hand, the locking protrusion 92d is fitted into the second locking portion 114c, thereby holding the separation lever 92 in the abutment position.

[0051] In the primary transfer unit 42 equipped with the above-described separation mechanism 64, the position of the primary transfer roller 60 is moved according to three conditions: color printing mode, monochrome printing mode, and attachment / detachment. In this embodiment, the color primary transfer rollers 60Y, 60M, and 60C are separated from and attached to the photosensitive drum 36 in response to instructions from the control unit 28. That is, the cam member 80 receives a driving force from the drive source, and rotates, causing the link member 78 to reciprocate between the color position and the monochrome position, thereby separating and attaching the color primary transfer rollers 60Y, 60M, and 60C to and from the photosensitive drum 36. Meanwhile, the black primary transfer roller 60K is separated and attached to the photosensitive drum 36 by manual operation of the separation lever 92 by the user. By displacing the black primary transfer roller 60K manually rather than through drive control, the separation mechanism 64 can be simplified and costs reduced. The operation of the separation mechanism 64 will now be described in detail.

[0052] 5, in the color printing mode, the cam member 80 is rotated appropriately in accordance with instructions from the control unit 28, and is held in a phase where the distance between its outer circumferential surface (the surface that abuts against the link member 78) and the cam shaft 88 is smallest. At this time, the link member 78 is held in the color position, which is the leftmost position, by the biasing force of the biasing member 86. When the link member 78 is in the color position, each pressing portion 82 of the link member 78 is spaced from the pressure receiving portion 84 of each arm member 76, and each arm member 76 maintains a state where each primary transfer roller 60 is in the abutting position by the biasing force of the biasing member 86.

[0053] 6, in the monochrome printing mode, the cam member 80 is rotated appropriately in accordance with instructions from the control unit 28 and is held in a phase in which the distance between its outer circumferential surface and the cam shaft 88 is greatest. The link member 78 is pushed to the right by the cam member 80, and moves to the monochrome position against the biasing force of the biasing member 86. When the link member 78 is in the monochrome position, the color pressing portions 82Y, 82M, and 82C of the link member 78 press the pressure-receiving portions 84Y, 84M, and 84C of the color arm members 76Y, 76M, and 76C to the right, causing the color arm members 76Y, 76M, and 76C to rotate in a direction that lifts the color primary transfer rollers 60Y, 60M, and 60C, respectively, and separates the color primary transfer rollers 60Y, 60M, and 60C from the corresponding color photosensitive drums 36Y, 36M, and 36C. On the other hand, the black arm member 76K maintains a state in which the black primary transfer roller 60K is disposed at the abutting position without receiving a pressing force from the link member 78. In this embodiment, in the standby mode (when no image is being formed), the state in the monochrome printing mode is maintained based on an instruction from the control unit 28.

[0054] 7, when removing the primary transfer unit 42 from the apparatus main body 12, the user moves the separation lever 92 to the abutment release position, whereby the black primary transfer roller 60K moves to the separation position and all of the primary transfer rollers 60 are positioned at the separation position. To move the separation lever 92 from the abutment position to the abutment release position, the user grasps the operation portion 92b and rotates the separation lever 92 to release the engagement between the locking protrusion 92d and the second locking portion 114c, and then pulls it toward the outlet side (right side) of the apparatus main body 12. Then, the separation lever 92 is rotated again to engage the locking protrusion 92d with the first locking portion 114b, whereby the separation lever 92 is held in the abutment release position. When the separation lever 92 is moved to the abutment release position, the pressing portion 92c of the separation lever 92 presses the pressure receiving portion 90a of the second arm member 90 to the right, causing the second arm member 90 to rotate so that the pressure receiving portion 90a tilts to the right. Accordingly, the other end (upper end) of the black arm member 76K is pulled to the right by the connecting member 94, causing the black arm member 76K to rotate in a direction lifting the black primary transfer roller 60K, separating the black primary transfer roller 60K from the black photosensitive drum 36K. Furthermore, the pre-transfer roller 62 and the tension roller move upward, releasing the pressure on the primary transfer belt 54 by the pre-transfer roller 62 and the tension roller. This reliably prevents the primary transfer belt 54 from interfering with the photosensitive drum 36 and the like and being damaged when the primary transfer unit 42 is removed from the device main body 12.

[0055] 13, in this embodiment, the couplings 102, 104 (the drive-side coupling 102 and the driven-side coupling 104) for transmitting the rotational drive force from the drive source to the drive roller 56 are coupled in a front-rear direction (second direction) perpendicular to the left-right direction (first direction) in which the primary transfer unit is attached and detached. Therefore, when removing the primary transfer unit 42 from the apparatus main body 12, it is necessary to retract all of the primary transfer rollers 60 to the separated positions and to release the couplings 102, 104 from each other. However, if the operation for connecting and disconnecting the primary transfer rollers 60 and the operation for disconnecting the couplings 102, 104 are performed separately, the number of operational steps required for removing the primary transfer unit 42 increases, which is inconvenient.

[0056] Therefore, in this embodiment, a release mechanism 100 is provided that releases the connection between the drive-side coupling 102 and the driven-side coupling 104 in conjunction with the user's operation of separating the black primary transfer roller 60K from the photosensitive drum 36 using the separating lever 92. The release mechanism 100 will be described in detail below with reference to FIGS. 9 to 15.

[0057] 9 and 10, the driven-side coupling 104 is provided so as to be reciprocatable in the front-rear direction (second direction), which is the axial direction of the drive roller 56. The driven-side coupling 104 is biased rearward, that is, in the direction of coupling (engagement) with the drive-side coupling 102, by a biasing member (not shown) such as a compression coil spring. In addition, a groove 104a is formed on the outer surface of the front end portion of the driven-side coupling 104 (the end portion opposite the drive-side coupling 102) to receive a pressing portion 132 of the release member 120, which will be described later.

[0058] The release mechanism 100 includes a release member 120 and a transmission member 122. The release member 120 is a member that converts the force that moves the separating lever 92 to the abutment release position into a force in the direction that causes the driven-side coupling 104 to move away from the drive-side coupling 102 and transmits the converted force to the driven-side coupling 104. On the other hand, the transmission member 122 is a member that transmits the force that moves the separating lever 92 to the abutment release position to the release member 120. In other words, the force that moves the separating lever 92 to the abutment release position is transmitted to the release member 120 via the transmission member 122, and the release member 120 is actuated by the transmission of this force, thereby releasing the connection between the drive-side coupling 102 and the driven-side coupling 104.

[0059] 9 and 10 as well as 11 to 13, the release member 120 has a receiving portion 130, a pressing portion 132, a support portion 134, etc. The release member 120 is formed in the shape of an arm extending in the left-right direction (first direction), and is provided on the primary transfer unit 42 so as to be rotatable about a rotation axis in the front-rear direction (second direction) and so as to be rotatable about a rotation axis in the up-down direction (third direction orthogonal to the first direction and the second direction).

[0060] Specifically, a receiving portion 130 is formed at the right end (one end in the first direction) of the release member 120, which receives a force that moves the separation lever 92 to the abutment release position. A pressing portion 132 is formed at the left end (the other end in the first direction) of the release member 120. When the receiving portion 130 receives a force accompanying the movement of the separation lever 92, the pressing portion 132 presses the driven-side coupling 104 to separate it from the drive-side coupling 102. A cylindrical support portion 134, whose axial direction is the front-to-rear direction, is formed at the center of the release member 120. That is, the support portion 134 has, at its upper portion, a first curved wall 134a that is convex upward, and a second curved wall 134b that is convex downward, at its lower portion. A cylindrical first protrusion 134c that protrudes upward is formed on the upper surface of the first curved wall 134a, and a first elongated hole 134d that extends in the left-to-right direction is formed in the second curved wall 134b.

[0061] The release member 120 is attached to the rear frame 72 such that the support portion 134 is sandwiched between a first wall 140 and a second wall 142 formed on the rear frame 72. The first wall 140 of the rear frame 72 is disposed above the support portion 134 of the release member 120 and extends horizontally. A second elongated hole 140a extending in the left-right direction is formed in the first wall 140, and a first protrusion 134c of the release member 120 is inserted into this second elongated hole 140a so as to be slidable in the left-right direction. Meanwhile, the second wall 142 of the rear frame 72 is disposed below the support portion 134 of the release member 120 and extends horizontally. A cylindrical second protrusion 142a protruding upward is formed on the upper surface of the second wall 142, and this second protrusion 142a is inserted into the first elongated hole 134d of the release member 120 so as to be slidable in the left-right direction. This allows the support portion 134 (and therefore the release member 120) to rotate about a rotation axis in the up-down direction relative to the rear frame 72. Furthermore, the second protrusion 142a and the first protrusion 134c slide in the left-right direction relative to the first elongated hole 134d and the second elongated hole 140a, respectively, while moving along the outer circumferential surfaces of the first curved wall 134a and the second curved wall 134b, thereby allowing the release member 120 to rotate about a rotation axis in the front-rear direction. In other words, the release member 120 can rotate about two axes, that is, about a rotation axis in the front-rear direction and about a rotation axis in the up-down direction.

[0062] Furthermore, the rear frame 72 has a third wall 144 disposed so as to extend horizontally below the pressing portion 132 of the release member 120. When the release member 120 is not receiving force from the transmission member 122, it rotates by its own weight so that the pressing portion 132 (left end portion) descends, but when the pressing portion 132 is engaged with the third wall 144, it becomes slightly lower to the left and maintains a state in which the pressing portion 132 is spaced apart from the driven-side coupling 104. Furthermore, the rear frame 72 has an inclined surface 146 below the receiving portion 130 of the release member 120 that slopes downward toward the rear.

[0063] 9 and 10, the transmission member 122 is attached to the shaft 92a of the separation lever 92 so as to move left and right together with the left and right movement of the separation lever 92. However, the diameter of the attachment hole formed in the transmission member 122 through which the shaft 92a passes is set larger than the diameter of the shaft 92a so that the transmission member 122 does not follow the rotation of the shaft 92a (the shaft 92a rotates but the transmission member 122 does not rotate). The transmission member 122 is formed to extend up to the upper side of the receiving portion 130 of the release member 120, and an inclined surface 122a that slopes downward toward the left is formed on the underside of the transmission member 122. This inclined surface 122a serves as a pressing portion for the release member 120 against the receiving portion 130.

[0064] Furthermore, a pressing portion 124 is formed on the right end of the rear frame 72 above the transmission member 122. The pressing portion 124 is formed in the shape of a rectangular plate extending in the left-right direction. This pressing portion 124 prevents the transmission member 122 from floating upward when the inclined surface 122a of the transmission member 122 presses the receiving portion 130 of the release member 120.

[0065] Next, the operation of the release mechanism 100 will be described. As shown in Figures 9 and 13, before operation, when the separating lever 92 is in the abutting position, the release member 120 is in a state in which it slopes slightly downward to the left and extends in the left-right direction. In this state, the pressing portion 132 of the release member 120 is separated from the driven-side coupling 104 and retracted downward, so that the rotation of the driven-side coupling 104 is not hindered. In addition, the inclined surface 122a of the transmission member 122 is not pressed against the receiving portion 130 of the release member 120.

[0066] When the separating lever 92 is moved from the abutment position to the abutment release position, as shown in FIGS. 14 and 15 , the inclined surface 122a of the transmission member 122 presses the receiving portion 130 of the releasing member 120, causing the releasing member 120 to rotate about the rotation axis in the front-to-rear direction so that the receiving portion 130 moves downward. Accompanying this rotation, the pressing portion 132 of the releasing member 120 moves upward and enters the groove 104a of the driven-side coupling 104. Furthermore, as the receiving portion 130 of the releasing member 120 moves downward, the lower surface of the receiving portion 130 abuts against the inclined surface 146 of the rear frame 72, causing the releasing member 120 to rotate about the rotation axis in the up-down direction so that the receiving portion 130 moves rearward. Accompanying this rotation, the pressing portion 132 of the releasing member 120 moves forward and presses the side surface of the groove 104a of the driven-side coupling 104 forward. As a result, the driven coupling 104 is moved forward, and the connection between the drive coupling 102 and the driven coupling 104 is released.

[0067] That is, in this embodiment, when removing the primary transfer unit 42 from the apparatus main body 12, the user moves the separation lever 92 to the abutment release position, whereby the black primary transfer roller 60K is displaced to the separation position and the connection between the drive-side coupling 102 and the driven-side coupling 104 is released. In other words, unless the user operates the separation lever 92 to displace the black primary transfer roller 60K to the separation position, the connection between the drive-side coupling 102 and the driven-side coupling 104 is maintained and movement of the primary transfer unit 42 in the removal direction is restricted. Therefore, removal of the primary transfer unit 42 without the primary transfer roller 60 being separated from the photosensitive drum 36 is reliably prevented.

[0068] Note that when the user moves the separation lever 92 from the abutment release position to the abutment position, the operation of the release mechanism 100 is reversed from the operation described above. Briefly, after the primary transfer unit 42 is attached to the apparatus main body 12, when the user moves the separation lever 92 to the abutment position, the black primary transfer roller 60K is displaced to the abutment position, and the pressure of the transmission member 122 against the receiving portion 130 of the release member 120 is released. Then, the release member 120 rotates by its own weight so that the pressing portion 132 lowers, and also rotates so that the pressing portion 132 moves rearward and returns to its original position. As a result, the pressure of the pressing portion 132 against the driven-side coupling 104 is released, and the driven-side coupling 104 moves rearward due to the biasing force of the biasing member and is connected to the drive-side coupling 102.

[0069] As described above, according to the first embodiment, the separation of the black primary transfer roller 60K and the decoupling of the couplings 102, 104 can be performed in a single operation, which is highly convenient. Also, it is possible to reliably prevent the primary transfer unit 42 from being removed from the apparatus main body 12 without the primary transfer roller 60 being separated from the photosensitive drum 36. Therefore, the primary transfer unit 42 can be easily and safely removed from the apparatus main body 12.

[0070] [Second Example] Next, an image forming apparatus 10 according to a second embodiment of this disclosure will be described with reference to Figures 16 to 19. In this second embodiment, the configuration of the release member 120 included in the release mechanism 100 differs from that of the first embodiment described above. As the other parts are similar, parts common to the first embodiment described above are given the same reference numerals, and duplicated descriptions will be omitted or simplified.

[0071] 16, the release member 120 of the second embodiment is composed of two members: a conversion member 150 and a pressing member 152. The conversion member 150 is a member that rotates about a bent portion 154 to convert a force that moves the separating lever 92 to the contact release position into a force that moves the driven-side coupling 104 away from the drive-side coupling 102. On the other hand, the pressing member 152 is a member that presses the driven-side coupling 104 to separate it from the drive-side coupling 102 when the conversion member 150 receives a force accompanying the movement of the separating lever 92.

[0072] 17 together with FIG. 16, the conversion member 150 is formed in a generally L-shape including a first arm 160 extending in the left-right direction (first direction) and a second arm 162 extending in the front-rear direction (second direction). A long hole 160a extending in the left-right direction is formed in the first arm 160, and a protrusion 174 of the pressing member 152 is slidably inserted into this long hole 160a. The second arm 162 is formed in a curved plate shape, and a tip end of the second arm 162 extends to a position corresponding to the upper end (pressure receiving portion 90a) of the second arm member 90. An insertion hole 154a is formed in the bent portion 154 of the conversion member 150, and a support shaft 180 provided on the rear frame 72 is rotatably fitted into this insertion hole 154a. That is, the conversion member 150 is rotatably attached to the rear frame 72 so that the first arm 160 moves back and forth in the left-right direction and the second arm 162 moves back and forth in the front-rear direction around the bent portion 154 (vertical support shaft 180).

[0073] 16 and 18, the pressing member 152 has a rectangular plate-shaped base 170 and is attached to the rear frame 72 so as to be reciprocable in the front-to-rear direction. A rectangular plate-shaped pressing portion 172 is formed on the lower surface of the rear end of the base 170 so as to protrude downward. This pressing portion 172 is engaged with the groove 104a of the driven-side coupling 104. In addition, a cylindrical protrusion 174 is formed on the upper surface of the rear end of the base 170 so as to protrude upward. This protrusion 174 is slidably inserted into the elongated hole 160a of the first arm 160.

[0074] In this embodiment, the pressing portion 92c of the separating lever 92 is used as a transmission member that transmits the force that moves the separating lever 92 to the contact release position to the conversion member 150 of the release member 120.

[0075] 16 and 19 , in the release mechanism 100 of the second embodiment, when the separating lever 92 is moved from the abutment position to the abutment release position, the pressing portion 92c of the separating lever 92 presses the second arm 162 of the conversion member 150, and the release member 120 is rotated about the support shaft 180 (a rotation axis in the vertical direction) so that the second arm 162 moves rightward. This rotation causes the first arm 160 of the conversion member 150 and the pressing member 152 to move forward, and the pressing portion 172 of the pressing member 152 presses forward against the side surface of the groove portion 104a of the driven-side coupling 104. As a result, the driven-side coupling 104 moves forward, and the connection between the drive-side coupling 102 and the driven-side coupling 104 is released.

[0076] In the second embodiment, as in the first embodiment, the separation of the black primary transfer roller 60K and the decoupling of the couplings 102, 104 can be performed in a single operation. Also, it is possible to reliably prevent the primary transfer unit 42 from being removed without the primary transfer roller 60 being separated from the photosensitive drum 36. Therefore, the primary transfer unit 42 can be easily and safely removed from the apparatus main body 12.

[0077] In the above-described embodiment, the image forming apparatus 10 is exemplified as a multifunction device that combines a copier, a facsimile, a printer, etc., but the image forming apparatus 10 may be any one of a copier, a facsimile, a printer, etc., or a multifunction device that combines at least two of these.

[0078] Furthermore, the specific part shapes and dimensions given above are merely examples and can be changed as appropriate according to the needs of the product specifications, etc. [Explanation of symbols]

[0079] 10...Image forming device 28...Control unit 30...Image forming unit 36...Photosensitive drum (photosensitive element) 42...Primary transfer unit 54...Primary transfer belt 60...Primary transfer roller 62…Detachment mechanism 92...Separation lever 100...Release mechanism 102...Drive side coupling 104 ... Driven side coupling 110...Rock section 120 ...Release member 122 ...Transmission member 130...Receiving 132 ...Pressing part 150...Conversion member 152 ...Pressing member

Claims

1. An image forming apparatus including a plurality of photosensitive members and a primary transfer unit detachably provided to a main body of the apparatus, a drive side coupling provided in the device body; and a driven-side coupling provided in the primary transfer unit and coupled to the drive-side coupling in a second direction perpendicular to a first direction in which the primary transfer unit is attached and detached; The primary transfer unit is a primary transfer belt onto which toner images are transferred from the plurality of photoreceptors; a plurality of primary transfer rollers arranged to face the respective photosensitive bodies with the primary transfer belt interposed therebetween; a contact / separation mechanism for contacting and separating the primary transfer roller with respect to the photosensitive member, the separation mechanism includes a separation lever that is provided to be reciprocally movable in the first direction and separates the black primary transfer roller from the photosensitive member, among the plurality of primary transfer rollers; an image forming apparatus including a release mechanism that releases the connection between the drive-side coupling and the driven-side coupling in conjunction with a user's operation of separating the black primary transfer roller from the photosensitive member using the separation lever.

2. 2. The image forming apparatus according to claim 1, wherein the release mechanism includes a release member provided in the primary transfer unit, which converts a force that moves the separation lever to the abutment release position into a force in a direction that causes the driven coupling to separate from the drive coupling, and transmits the force to the driven coupling.

3. 3. The image forming apparatus according to claim 2, wherein the release member is provided on the primary transfer unit so as to extend in the first direction, is rotatable around a rotation axis in the second direction, and is rotatable around a rotation axis in a third direction perpendicular to the first direction and the second direction.

4. The release member is a receiving portion formed at one end in the first direction and configured to receive a force that moves the separating lever to the abutment release position; and 4. The image forming apparatus according to claim 3, further comprising a pressing portion formed at the other end in the first direction, the pressing portion pressing the driven-side coupling to separate it from the drive-side coupling when the receiving portion receives a force accompanying the movement of the separating lever.

5. The release member is a conversion member that is formed in a substantially L-shape and that converts a force that moves the separation lever to the abutment release position by rotating around a bent portion into a force in a direction in which the driven-side coupling separates from the drive-side coupling; and 3. The image forming apparatus according to claim 2, further comprising a pressing member that is reciprocally movable in the second direction and presses the driven-side coupling to separate it from the drive-side coupling when the conversion member receives a force accompanying the movement of the separation lever.

6. 6. The image forming apparatus according to claim 1, wherein the primary transfer unit includes a locking portion that holds the separation lever in a state where the separation lever is in a contact release position.

Images