Image forming apparatus

Abstract

The present invention provides an image forming apparatus that can oscillate a developing device even when the developing member and the drive input member are aligned in the axial direction. [Solution] The image forming apparatus 1 includes a connecting / separating device 15 that rotates the developing device 22 between a developing position and a separated position P2. Multiple developing devices 22 are provided to correspond to monochrome and color images. The developing roller 31 is positioned offset to one side (to the right) in the axial direction from the drive input gear and is connected to the right end of the drive input gear. The connecting / separating device 15 either separates the developing roller 31 from the drive input gear and then rotates the developing device 22 to the separated position P2, or rotates the developing device 22 to the developing position and then connects the developing roller 31 to the drive input gear. The connecting / separating device 15 switches between a state in which all developing devices 22 are positioned at the separated position P2 or the developing position, and a monochrome printing state in which the developing device 22 for monochrome images is positioned at the developing position and the developing device 22 for color images is positioned at the separated position P2.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] An electrophotographic image forming apparatus includes a developing device including a developer carrier that develops a latent image while rotating in proximity to or in contact with an image carrier, a moving mechanism that swings the developing device, and a drive input gear that inputs a driving force to the developer carrier via a drive transmission gear. The developing device is provided so as to be swingable between a developing position where the developer carrier is in proximity to or in contact with the image carrier and first to second separation positions (hereinafter referred to as "separation positions") where the developer carrier is separated from the image carrier. The swing fulcrum of the developing device is provided on the side opposite to the drive input gear with the drive transmission gear interposed therebetween. In a state where the developing device is at the developing position, the central axis of the drive transmission gear is located on the downstream side in the rotational direction toward the separation position from a straight line connecting the swing fulcrum and the central axis of the drive input gear, and the developing device is allowed to rotate from the developing position to the separation position. During a period when image formation (printing) is stopped in the image forming apparatus, the developing device is rotated to the separation position, so that the developer carrier is separated from the image carrier and the drive transmission gear is separated from the drive input gear. Thereby, deterioration of the developer in the developing device is prevented.

[0003] Four developer carriers, four developing devices, four drive transmission gears, and four drive input gears are provided respectively. The moving mechanism has a drive mechanism that reciprocates a link member that presses the developing device. The drive mechanism switches between a first state in which a monochrome developing device is arranged at the developing position and other developing devices are arranged at the separation positions, a second state in which all the developing devices are arranged at the separation positions, and a third state in which all the developing devices are arranged at the developing positions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] In the image forming apparatus described above, the pivot point, drive transmission gear, and drive input gear of the developing device were arranged in roughly a straight line on a plane perpendicular to the axial direction of the image carrier, etc. As a result, the transmission of driving force to the developer carrier was released when the developing device was rotated to a separated position. However, arranging the pivot point and the two gears in a straight line on a plane perpendicular to the axial direction requires a large space, and depending on the size of the image forming apparatus, it was sometimes not possible to secure the necessary space.

[0006] To address the above problem, one might consider connecting the drive transmission gear and the drive input gear in the axial direction. However, in this case, the developing device cannot be rotated around the pivot point unless the connection between the drive transmission gear (developer carrier) and the drive input gear is released. Therefore, the image forming apparatus described above could not be adapted to a structure in which the developer carrier and the member that inputs the driving force are aligned in the axial direction.

[0007] In consideration of the above circumstances, the present invention provides an image forming apparatus that can oscillate even when the developing member and the drive input member are aligned in the axial direction. [Means for solving the problem]

[0008] The image forming apparatus of the present invention comprises: an image carrier mounted on the apparatus body so as to be movable in the axial direction and carrying a latent image while rotating around an axis; a developing member that rotates around an axis while approaching or in contact with the image carrier and developing the latent image; a developing member mounted on the apparatus body so as to be movable in the axial direction and rotating around a pivot axis arranged parallel to the developing member; a contacting / separating device that rotates the developing device between a developing position in which the developing member is approaching or in contact with the image carrier and a separation position in which the developing member is separated from the image carrier; and a drive input member that is rotatably supported by the contacting / separating device and inputs a driving force to the developing member. The image carrier, the developing device, and the drive input member are each provided in multiple quantities corresponding to monochrome images and color images, and the multiple image carriers, multiple developing devices, and multiple drive input members are each arranged in a contacting / separating direction perpendicular to the axial direction. The image carrier and the developing device are removable from the device body in one direction in the axial direction when the developing device is positioned in the separated position, the developing member is positioned offset in one direction in the axial direction from the drive input member and connected to one end of the drive input member in the axial direction, the connecting / disconnecting device separates the developing member and the drive input member in the axial direction, rotates the developing device from the developing position to the separated position, and connects the developing member and the drive input member in the axial direction after rotating the developing device from the separated position to the developing position, and the connecting / disconnecting device switches to one of the following states: an insertable / removable state with all the developing devices positioned in the separated position, a normal printing state with all the developing devices positioned in the developing position, and a monochrome printing state with the developing device for monochrome images positioned in the developing position and the developing device for color images positioned in the separated position.

[0009] In this case, the developing member approaches or contacts the image carrier from one of the connecting / separating directions and is connected to one end of the drive input member in the axial direction via a cylindrical drive coupling, and the connecting / separating device includes a support member that supports the drive coupling so as to be rotatable and movable in the axial direction, a plurality of release arms that are rotatably provided along the outer circumferential surface of the drive coupling and move in the axial direction by rotating while contacting an inclined surface formed on the support member, and a first slider that is movable between an engagement direction, which is one of the connecting / separating directions, and an engagement / disengagement direction, which is the other of the connecting / separating directions, and the first slider includes a monochrome slider corresponding to the developing device for monochrome images and a color slider corresponding to the developing device for color images, and the monochrome slider and the color slider each have a first projection that is provided so as to be able to contact the release arm and a second projection that is provided so as to be able to contact the developing device, and when the first slider is moved in the engagement direction, the first projection pushes the release arm in the engagement direction, and the release arm When the drive coupling is separated from the developing member by rotating in the engagement direction while contacting the inclined surface, and then the second projection pushes the developing device in the engagement direction, rotating it from the developing position to the separated position, and the first slider is moved in the disengagement direction, the second projection separates from the developing device in the disengagement direction, the developing device rotates from the separated position to the developing position, and then the first projection separates from the release arm in the disengagement direction, and the release arm disengages while contacting the inclined surface. By rotating in the direction, the drive coupling is connected to the developing member, and in the insertable state, the monochrome slider and the color slider move in the engagement direction, all the first projections push all the release arms, and all the second projections push all the developing device, and in the normal printing state, the monochrome slider and the color slider move in the disengagement direction, all the second projections move away from all the developing device, and all the first projections move away from all the release arms, and in the monochrome printing state,The monochrome slider moves in the disengagement direction, the second projection of the monochrome slider separates from the developing device for the monochrome image, the first projection of the monochrome slider separates from the release arm, the color slider moves in the engagement direction, the first projection of the color slider pushes the release arm, and the second projection of the color slider pushes the developing device for the color image.

[0010] In this case, the connecting / disconnecting device further includes a second slider that is movable between the engagement direction and the disengagement direction in conjunction with the first slider, the first slider and the disengagement arm are provided on the other axial side of the support member, the second projection contacts the other axial end of the developing device, the second slider is provided on one axial side of the support member and has a third projection that is provided to contact the one axial end of the developing device, and when the first slider and the second slider are moved in the engagement direction, the drive coupling separates from the developing member, When the second and third projections push the developing device in the engagement direction, causing it to rotate from the developing position to the separated position, and the first and second sliders are moved in the disengagement direction, the drive coupling connects to the developing member after the second and third projections have moved away from the developing device in the disengagement direction, and in the removable state, all of the third projections push all of the developing devices and guide the developing devices as they are pulled out of the device body, and in the normal printing state and the monochrome printing state, all of the third projections are separated from all of the developing devices.

[0011] In this case, the connecting / disconnecting device further comprises: a first link rotatably supported by the support member and engaging with the monochrome slider; a second link rotatably supported by the support member and engaging with the first link and the second slider; a manual lever connected to the rotation axis of the second link; a slide drive unit that moves the color slider toward the engagement direction; and a biasing member that biases the color slider toward the disengagement direction. As the manual lever is rotated, the second link rotates in the same direction as the manual lever, and the first link rotates in the opposite direction to the manual lever in conjunction with the second link. When the manual lever is rotated to one side, the first link moves the monochrome slider together with the color slider toward the engagement direction. When the second link moves the second slider in the engagement direction and the manual lever is rotated to the other, the first link moves the monochrome slider in the disengagement direction, the biasing member moves the color slider in the disengagement direction, the second link moves the second slider in the disengagement direction, in the insertable state the manual lever is rotated to one side, in the normal printing state the manual lever is rotated to the other side, in the monochrome printing state the manual lever is rotated to the other side, the slide drive unit moves the color slider in the disengagement direction, the first projection of the color slider pushes the release arm, and the second projection of the color slider pushes the developing device for the color image. [Effects of the Invention]

[0012] According to the present invention, the developing device can be oscillated even if the developing member and the drive input member are aligned in the axial direction. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing an image forming apparatus according to one embodiment of the present invention. [Figure 2] This is a schematic diagram (side view) showing the internal structure of an image forming apparatus according to one embodiment of the present invention. [Figure 3] It is a perspective view showing a photosensitive drum, a developing device, a separating and contacting device, etc. of an image forming apparatus according to an embodiment of the present invention. [Figure 4] It is a plan view showing a separating and contacting device (initial state, normal printing state) of an image forming apparatus according to an embodiment of the present invention. [Figure 5] It is a sectional view taken along the line V-V of FIG. 4. [Figure 6] It is a right side view showing a photosensitive drum, a developing device (developing position), and a separating and contacting device of an image forming apparatus according to an embodiment of the present invention. [Figure 7] It is an exploded perspective view showing a rotation transmission device, a separating and contacting device, etc. of an image forming apparatus according to an embodiment of the present invention. [Figure 8] It is an explanatory view (left side view, sectional view taken along the line A-A) explaining a state in which a driving force can be transmitted to a developing roller, which is a rotation transmission device of an image forming apparatus according to an embodiment of the present invention. [Figure 9] It is an explanatory view (left side view, sectional view taken along the line B-B) explaining a state in which a driving force cannot be transmitted to a developing roller, which is a rotation transmission device of an image forming apparatus according to an embodiment of the present invention. [Figure 10] It is an exploded perspective view showing a separating and contacting device of an image forming apparatus according to an embodiment of the present invention. [Figure 11] It is a plan view showing a separating and contacting device (insertable state) of an image forming apparatus according to an embodiment of the present invention. [Figure 12] It is a sectional view taken along the line XII-XII of FIG. 11. [Figure 13] It is a right side view showing a photosensitive drum, a developing device (separated position), and a separating and contacting device of an image forming apparatus according to an embodiment of the present invention. [Figure 14] It is a plan view showing a separating and contacting device (monochrome printing state) of an image forming apparatus according to an embodiment of the present invention. [Figure 15] It is a sectional view taken along the line XV-XV of FIG. 14.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described while referring to the attached drawings. In the drawings, Fr, Rr, L, R, U, and D indicate front, rear, left, right, up, and down. Also, the front-rear direction (approach / separation direction), the left-right direction (axial direction), and the up-down direction are orthogonal to each other. In this specification, terms indicating directions and positions are used for convenience of explanation and do not limit the technical scope of the present invention. Also, in each figure, the shape, dimensions, angles, etc. of each component member are not exact and are schematized for explanation purposes.

[0015] [Image forming apparatus] Referring to FIGS. 1 to 3, the image forming apparatus 1 according to this embodiment will be described. FIG. 1 is a perspective view showing the image forming apparatus 1. FIG. 2 is a schematic view (side view) showing the image forming apparatus 1. FIG. 3 is a perspective view showing the photosensitive drum 20, the developing device 22, the approach / separation device 15, etc.

[0016] The image forming apparatus 1 is a printer that forms an image on a sheet S (medium) by an electrophotographic method. As shown in FIGS. 1 and 2, the image forming apparatus 1 includes an apparatus main body 2 having a substantially rectangular parallelepiped appearance. A paper feed cassette 3 for accommodating the sheet S is detachably attached to the lower part of the apparatus main body 2. A paper discharge tray 4 for receiving the sheet S on which an image is formed is provided on the upper surface of the apparatus main body 2. Note that the apparatus main body 2 includes a frame that constitutes the skeleton of the image forming apparatus 1 and an exterior member that is attached to the frame and constitutes the exterior of the image forming apparatus 1. Also, the sheet S is not limited to paper and may be made of resin or the like. Also, in this specification, the terms "upstream" and "downstream" and similar terms refer to the "upstream" and "downstream" in the conveyance direction of the sheet S and similar concepts.

[0017] As shown in FIG. 2, inside the apparatus main body 2, a conveyance path 8 for conveying the sheet S from the paper feed cassette 3 to the paper discharge tray 4 is provided. A paper feed device 5 is provided at the upstream end of the conveyance path 8, an image forming device 6 is provided in the middle part of the conveyance path 8, and a fixing device 7 is provided on the downstream side of the conveyance path 8.

[0018] The imaging apparatus 6 comprises an intermediate transfer belt 10, four image forming units 11A to 11D, and an exposure apparatus 12. The intermediate transfer belt 10 is wound around a plurality of rollers located above the paper feed cassette 3. One roller connected to a belt drive motor (not shown) is rotated, causing the intermediate transfer belt 10 to rotate counterclockwise in Figure 2. The four image forming units 11A to 11D are arranged in a front-to-back direction (away-from-front direction) above the intermediate transfer belt 10. As an example, the four image forming units 11A to 11D form images of yellow, magenta, cyan, and black in order from rear to front in Figure 2. The exposure apparatus 12 is located above the four image forming units 11A to 11D.

[0019] Since the four image forming units 11A to 11D have substantially the same structure, in this specification, when describing the four image forming units 11A to 11D in common, we may focus on any one of the image forming units 11 and use only Arabic numerals for their designations. Furthermore, the designations of the components included in the image forming units 11A to 11D, and the designations of the components provided in correspondence with the image forming units 11A to 11D, may also be "A, B, C, D". In addition, in this specification, we may mainly focus on any one of these components and use only Arabic numerals for their designations.

[0020] The image forming units 11A to 11D include photoreceptor drums 20A to 20D, charging devices 21A to 21D, developing devices 22A to 22D, primary transfer rollers 23A to 23D, and cleaning devices 24A to 24D. There are four of each of the photoreceptor drums 20A to 20D, charging devices 21A to 21D, developing devices 22A to 22D, primary transfer rollers 23A to 23D, and cleaning devices 24A to 24D, corresponding to monochrome images using black toner and color images using toners of colors other than black.

[0021] As an example of an image carrier, the photoreceptor drum 20 is formed in a cylindrical shape extending in the left-right direction and is housed in a photoreceptor container 26 (26A~26D) to form a unit (see Figure 3). The photoreceptor drum 20 is supported in the photoreceptor container 26 so as to be rotatable around its axis. The photoreceptor drum 20 is rotationally driven by a drive motor (not shown) connected via a power transmission mechanism (not shown) such as a gear train, while in contact with the intermediate transfer belt 10. The charging device 21, developing device 22, primary transfer roller 23, and cleaning device 24 are arranged around the photoreceptor drum 20 in order of the image formation process. The primary transfer roller 23 faces the photoreceptor drum 20 across the intermediate transfer belt 10. The secondary transfer roller 25 is in contact with the rear side of the intermediate transfer belt 10.

[0022] The developing device 22 is located, for example, behind the photoreceptor drum 20. The developing devices 22A to 22D include developing containers 30A to 30D, developing rollers 31A to 31D, and supply rollers 32A to 32D. The developing container 30 is connected to a toner container (not shown) via a supply passage (not shown) and is formed to store toner (developer) supplied from the toner container. The four developing containers 30A to 30D are filled with yellow, magenta, cyan, and black toners, for example, in order from rear to front in Figure 2. The developing rollers 31 and supply rollers 32 are located inside the developing container 30 and are rotatably supported around the axis of the developing container 30. The developing roller 31, as an example of a developing member, is positioned to approach the photoreceptor drum 20 from the rear (more specifically from the rear-upward diagonal direction (one of the moving-away directions)). Specifically, regulating rollers (not shown) provided at both axial ends of the developing roller 31 contact the circumferential surface of the photoreceptor drum 20, so that the circumferential surfaces of the photoreceptor drum 20 and the developing roller 31 are positioned close together with a predetermined gap between them. The supply roller 32 is positioned below the developing roller 31 and supplies toner from the developing container 30 to the circumferential surface of the developing roller 31. Although the developing roller 31 is positioned close to the photoreceptor drum 20, it is not limited to this position; it may also rotate around its axis while in contact with the photoreceptor drum 20.

[0023] As will be described in more detail later, the developing roller 31 and the supply roller 32 are connected to the drive motor via a drive input gear 36, a drive coupling 38, etc. The developing roller 31 is rotationally driven by the drive force received from the drive motor. The supply roller 32 is rotationally driven in conjunction with the developing roller 31.

[0024] [Image Forming Processing] The image forming apparatus 1 forms an image on a sheet of paper S based on image data transmitted from, for example, an external terminal (such as a personal computer). A control unit (not shown) provided in the image forming apparatus 1 controls the image forming apparatus 1 based on the input image data, and the image forming process is executed as follows.

[0025] The charging device 21 charges the surface of the photoreceptor drum 20. The exposure device 12 exposes the photoreceptor drum 20 to the image data, forming an electrostatic latent image on the surface of the photoreceptor drum 20. The photoreceptor drum 20 carries the electrostatic latent image while rotating around its axis. The developing roller 31 of the developing device 22 rotates around its axis in close proximity to the photoreceptor drum 20, supplying toner to the photoreceptor drum 20 and developing the electrostatic latent image on the photoreceptor drum 20. The four toner images carried on the four photoreceptor drums 20A to 20D are sequentially transferred to the intermediate transfer belt 10 by the primary transfer rollers 23A to 23D to which a primary transfer bias is applied. As a result, a full-color toner image is formed on the surface of the intermediate transfer belt 10.

[0026] The paper S is fed from the paper feed cassette 3 to the transport path 8 by the paper feed device 5, and the toner image supported on the intermediate transfer belt 10 is secondarily transferred to the paper S by the secondary transfer roller 25 to which a secondary transfer bias is applied. The toner image is heat-fixed to the paper S by the fuser device 7, and then the paper S is discharged into the output tray 4. Toner remaining on the surface of the photoreceptor drum 20 is removed by the cleaning device 24, and the charge on the photoreceptor drum 20 is removed by the static elimination device (not shown).

[0027] Incidentally, in the image forming apparatus 1, for example, the photoreceptor drum 20 and the developing device 22 are mounted on the apparatus body 2 so as to be movable in the left-right direction (axial direction) for maintenance and replacement of the photoreceptor drum 20 and the developing device 22. As an example, a cover 2A (see Figure 1) is provided on the right side of the apparatus body 2 so as to be openable and closable. By opening the cover 2A, the right side of the image forming apparatus 6, including the developing device 22, is exposed (see Figure 3), and the developing device 22, etc., can be attached and detached. The cover 2A is provided so as to be rotatable on a hinge (not shown) provided at the rear, spaced apart in the vertical direction. Furthermore, since the photoreceptor drum 20 is housed in a photoreceptor container 26 and is unitized, more precisely, the unitized photoreceptor drum 20 is attached to and detached from the apparatus body 2.

[0028] If the photoreceptor drum 20 or the developing device 22 is attached or detached while the developing roller 31 is in close proximity to the photoreceptor drum 20, there is a risk that the developing roller 31 or the photoreceptor drum 20 may come into contact and be damaged. Therefore, when attaching or detaching the photoreceptor drum 20, etc., it is necessary to pull the developing roller 31 away from the photoreceptor drum 20. In addition, before pulling the developing roller 31 (developing device 22) away from the photoreceptor drum 20, it is also necessary to disconnect the developing roller 31 from the drive motor.

[0029] Furthermore, when forming a monochrome image, it is preferable to separate the color image developing roller 31 from the photoreceptor drum 20 in order to suppress deterioration of the color image developing roller 31 and the photoreceptor drum 20. In addition, when forming a monochrome image, it is preferable to disconnect the color image developing roller 31 from the drive motor in order to suppress deterioration of the toner due to continuous agitation in the developing container 30 of the color image developing device 22.

[0030] Therefore, the image forming apparatus 1 according to this embodiment is equipped with a connecting / disconnecting device 15 that separates the developing roller 31 from the photoreceptor drum 20 and disconnects it from the drive motor when attaching or detaching the developing apparatus 22 to the apparatus body 2.

[0031] Prior to describing the contact / disconnection device 15, the rotational transmission devices 14A to 14D, which transmit driving force (rotational force) to the developing devices 22A to 22D and developing rollers 31A to 31D, will be further described with reference to Figures 4 to 9. Figure 4 is a plan view showing the contact / disconnection device 15. Figure 5 is a cross-sectional view of VV in Figure 4. Figure 6 is a right side view showing the photoreceptor drum 20, developing device 22, and contact / disconnection device 15. Figure 7 is an exploded perspective view showing the rotational transmission device 14 and the contact / disconnection device 15, etc. Figures 8 and 9 are explanatory diagrams (left side view and cross-sectional view) illustrating the rotational transmission device 14.

[0032] [Developing equipment] The developing device 22 is supported by the device body 2 so as to be able to swing in the front-rear direction. Specifically, as shown in Figure 5, the developing device 22 rotates around a pivot axis 33 (33A~33D) which is positioned parallel to the developing roller 31 and radially offset from the developing roller 31. The pivot axis 33 is provided on both sides of the developing container 30 in the left-right direction. When viewing the developing container 30 from the side, the pivot axis 33 is positioned below (more specifically, diagonally downward and rearward) from the center of rotation of the developing roller 31 (see the cross-shaped mark in Figure 5). The developing device 22 rotates between a developing position P1 (see Figures 5 and 6) in which the developing roller 31 is close to the photoreceptor drum 20, and a separated position P2 (see Figure 12, described later) in which the developing roller 31 is separated rearward from the photoreceptor drum 20. The photoreceptor drum 20 and the developing device 22 can be pulled out from the main body 2 toward the right (one side in the axial direction) when the developing device 22 is positioned at the separated position P2. Although not shown in the figures, the developing container 30 is provided with a return member (not shown) that biases the developing device 22 from the separated position P2 toward the developing position P1.

[0033] As shown in Figure 5, first engaging portions 34A to 34D are provided on the upper left end of the developing containers 30A to 30D. The first engaging portion 34 is formed as a projection that protrudes upward from the upper left end of the developing container 30. As shown in Figure 6, second engaging portions 35A to 35D are provided on the upper part of the developing containers 30A to 30D, extending almost the entire length in the left-right direction. When viewed from the side, the second engaging portion 35 is formed as a roughly L-shaped rail that protrudes upward from the upper part of the developing container 30 and bends forward.

[0034] [Rotational transmission device] As shown in Figure 7, the rotary transmission devices 14A to 14D are located to the left (on the other side in the axial direction) of the developing devices 22A to 22D. The rotary transmission devices 14A to 14D include drive input gears 36A to 36D, drive transmission gears 37A to 37D (see Figures 8 and 9), and drive couplings 38A to 38D. There are four sets of drive input gears 36A to 36D, drive transmission gears 37A to 37D, and drive couplings 38A to 38D, corresponding to monochrome and color images, respectively. The drive input gear 36, drive transmission gear 37, and drive coupling 38 are arranged in a line in the left-right direction (axial direction).

[0035] <Drive input gear, drive transmission gear> The drive input gear 36 (drive input member) is, for example, a spur gear and is rotatably supported around an axis by a contacting / disconnecting device 15, which will be described later. The drive input gear 36 is connected to a drive motor via a gear train (not shown) or the like. The drive transmission gear 37 is, for example, a spur gear and is rotatably supported around an axis by the developing container 30. The drive transmission gear 37 is connected to the developing roller 31 and the supply roller 32 via an intermediate gear (not shown) or the like.

[0036] <Drive coupling> As shown in Figures 7 and 8, the drive coupling 38 is formed in a substantially cylindrical shape with its right end face closed. A pair of drive ribs 39 (39A to 39D) protrude radially outward from the outer circumferential surface of the drive coupling 38. The pair of drive ribs 39 are positioned symmetrically with respect to the axis of the drive coupling 38. The drive coupling 38 is provided to be movable in the left-right direction (axial direction) between the drive input gear 36 and the drive transmission gear 37. The drive coupling 38 moves between a connection position P3 (see Figure 8) that connects the drive input gear 36 and the drive transmission gear 37, and a separation position P4 (see Figure 9) that approaches the drive input gear 36 and moves away from the drive transmission gear 37.

[0037] A biasing connecting member 40 (40A~40D) (for example, a compression coil spring) is housed in the axial center of the drive coupling 38. The biasing connecting member 40 is mounted between the drive input gear 36 and the drive coupling 38, biasing the drive coupling 38 toward the drive transmission gear 37. In other words, the drive coupling 38 is pushed toward the coupling position P3 by the biasing connecting member 40 (see Figure 8).

[0038] The developing roller 31 is positioned offset to the right (one side in the axial direction) from the drive input gear 36. When the drive coupling 38 is positioned at connection position P3, the developing roller 31 is connected to the right side (one end in the axial direction) of the drive input gear 36 via the drive transmission gear 37 and the drive coupling 38. As a result, the drive input gear 36 becomes capable of inputting driving force to the developing roller 31 and the supply roller 32 via the drive transmission gear 37 and the drive coupling 38.

[0039] [Detachment device] Next, the connecting / disconnecting device 15 will be described with reference to Figures 4 to 10. Figure 10 is an exploded perspective view showing the connecting / disconnecting device 15.

[0040] The connecting / disconnecting device 15 has the function of rotating the developing device 22 between the developing position P1 and the separated position P2, and the function of switching the connection state between the developing roller 31 and the drive input gear 36. As shown in Figure 7, the connecting / disconnecting device 15 includes a support member 41, release arms 50A to 50D, a first slider 54, a second slider 58, a first link 64, a second link 65, a manual lever 66, and a slide drive unit 67 (see Figure 4).

[0041] <Support member> As shown in Figure 7, the support member 41 has a support body portion 42 and a mounting guide 43. The support body portion 42 is formed in a flat plate shape that covers the top of the four developing devices 22A to 22D (see Figure 6). A rail portion 44 is provided hanging down from the lower surface of the support body portion 42, which supports the unitized photoreceptor drum 20 and developing device 22 so that they can slide in the left-right direction (axial direction) (see Figure 6).

[0042] The mounting guide 43 is attached to the left end (the other end in the axial direction) of the support body 42, with a gap in which the first slider 54, described later, can be positioned (see Figure 10). The mounting guide 43 has shaft holes 45A to 45D formed at equal intervals in the front-rear direction (away-from direction). The shaft hole 45 is a circular opening into which the drive coupling 38 is inserted. The mounting guide 43 (support member 41) supports the drive coupling 38 so that it can rotate and move in the left-right direction (axial direction). In addition, inclined surfaces 46A to 46D are formed on the left surface of the mounting guide 43 along the rear edges of the shaft holes 45A to 45D. The inclined surface 46 has a surface that slopes from top to bottom and to the left (the other side in the axial direction).

[0043] <Release Arm> As shown in Figure 7, the release arms 50A to 50D are provided to the left of the support member 41 (the other side in the axial direction). As shown in Figures 7 and 8, the release arm 50 has an annular portion 51 (51A to 51D) and an arm portion 52 (52A to 52D).

[0044] The annular portion 51 is formed in an annular shape, and the drive coupling 38 is inserted into the annular portion 51. As a result, the release arm 50 is rotatably mounted along the outer circumferential surface of the drive coupling 38. The arm portion 52 extends radially outward from the outer circumferential surface of the annular portion 51. The arm portion 52 is formed to be in contact with the inclined surface portion 46 formed on the mounting guide 43 (support member 41). The release arm 50 moves in the left-right direction (axial direction) by rotating while the arm portion 52 is in contact with the inclined surface portion 46.

[0045] As shown in the upper part of Figure 9, when the release arm 50 rotates counterclockwise and moves to the left, as shown in the lower part of Figure 9, the tip (left end) of the annular portion 51 abuts against the drive rib 39, causing the drive coupling 38 to move to the left against the biasing force of the biasing connecting member 40. As a result, the drive coupling 38 is separated from the drive transmission gear 37, and the transmission of driving force to the developing roller 31 is interrupted.

[0046] <First Slider> As shown in Figures 4 and 7, the first slider 54 is provided to the left of the support member 41 (the other side in the axial direction). More specifically, the first slider 54 is positioned in the gap between the support body 42 and the mounting guide 43 (see also Figure 10). The first slider 54 includes a monochrome slider 55 corresponding to the monochrome image developing device 22D and a color slider 56 corresponding to the color image developing devices 22A to 22C. The monochrome slider 55 and the color slider 56 are each formed in the shape of an elongated rod in the front-rear direction. For the sake of explanation, in this specification, the rear (one side in the connecting / separating direction) will be referred to as the "engagement direction D1," and the front (the other side in the connecting / separating direction) will be referred to as the "disengagement direction D2." Therefore, the first slider 54 is provided to be movable between the engagement direction D1 and the disengagement direction D2.

[0047] (Monochrome slider) The monochrome slider 55 is supported by the mounting guide 43 so as to be movable in the front-rear direction (away-from direction). As shown in Figure 7, the monochrome slider 55 has a slider housing portion 55a formed in the portion excluding the front side, which is capable of accommodating the color slider 56. The slider housing portion 55a is formed by cutting a large notch into the left side of the monochrome slider 55, and a stopper step portion 55b is formed at the front end of the slider housing portion 55a. In addition, a first joint shaft portion 57 (see Figure 4) is formed at the rear end of the monochrome slider 55 via a bracket 55c that protrudes to the right. The first joint shaft portion 57 protrudes downward from the lower surface of the bracket 55c.

[0048] As shown in Figures 4, 5, and 7, the monochrome slider 55 has a first projection 61D that is provided so as to be able to contact the release arm 50D for monochrome images, and a second projection 62D that is provided so as to be able to contact the left end of the developing device 22D for monochrome images. The first projection 61D protrudes to the left from the lower part of the left side of the monochrome slider 55, excluding the slider housing 55a, on the front side of the monochrome slider 55. The second projection 62D protrudes to the right from the lower part of the right side of the monochrome slider 55, on the front side of the monochrome slider 55. The second projection 62D is provided in a position shifted forward (in the disengagement direction D2) compared to the first projection 61D.

[0049] (Color slider) As shown in Figures 4, 5, and 7, the color slider 56 is supported so as to be movable in the front-rear direction in the slider housing portion 55a of the monochrome slider 55. A biasing housing portion 56a (see Figure 7) capable of housing a biasing member 60 is formed on the rear side of the color slider 56. The biasing member 60 is, for example, a compression coil spring, which is installed between the front end of the biasing housing portion 56a and the rear end of the mounting guide 43, and biases the color slider 56 forward (in the disengagement direction D2).

[0050] The color slider 56 has first projections 61A to 61C that are provided so as to be able to contact the release arms 50A to 50C for color images, and second projections 62A to 62C that are provided so as to be able to contact the left end of the developing devices 22A to 22C for color images. The three first projections 61A to 61C are arranged at approximately equal intervals in the front-rear direction and protrude to the left from the lower part of the left side of the color slider 56. The three second projections 62A to 62C are arranged at approximately equal intervals in the front-rear direction and protrude to the right from the lower part of the right side of the color slider 56. The second projection 62A is provided at a position shifted forward (in the release direction D2) compared to the first projection 61A. Similarly, the second projections 62B and 62C are provided at positions shifted forward compared to the first projections 61B and 61C, respectively.

[0051] <Second Slider> As shown in Figures 4, 7, and 10, the second slider 58 is formed in the shape of an elongated rod in the front-rear direction and is provided to the right of the support member 41 (on one side in the axial direction). The second slider 58 is supported by the support body 42 so as to be movable in the front-rear direction (toward and away direction). As will be described in detail later, the second slider 58 is provided so as to be movable between the engagement direction D1 and the disengagement direction D2 in conjunction with the first slider 54.

[0052] As shown in Figures 4 and 6, the second slider 58 has four third projections 63A to 63D that are provided so as to be able to contact the right end (one end in the axial direction) of the developing devices 22A to 22D. The four third projections 63A to 63D are arranged at approximately equal intervals in the front-rear direction and protrude to the left from the lower left side of the second slider 58. The four third projections 63A to 63D are positioned opposite the four second projections 62A to 62D of the first slider 54, with the four developing devices 22A to 22D in between. In addition, an engagement groove 58a is formed on the upper rear side of the second slider 58, which is inclined backward from left to right when viewed from a plan view (see Figure 10).

[0053] <Link 1> As shown in Figures 4, 7, and 10, the first link 64 is formed as a flat plate bent in a generally L-shape ("V" shape) and is rotatably supported by the support member 41. More specifically, the first link 64 is supported by a first support shaft portion 47 located at the rear of the upper surface of the support body portion 42 and approximately in the center in the left-right direction. The first link 64 is also engaged with the first slider 54. More specifically, an elongated hole 70 (see Figure 7) is formed at the left end of the first link 64, into which the first joint shaft portion 57 of the mono slider 55 is inserted (see Figure 4). The first joint shaft portion 57 is supported so as to be movable and rotatable along the elongated hole 70. Furthermore, an engagement recess 71 is formed at the right end of the first link 64.

[0054] <Second Link> The second link 65 is formed as a flat plate bent in a generally L-shape ("V" shape) and is rotatably supported by the support member 41. More specifically, the second link 65 is bent in the opposite direction to the first link 64 when viewed from above and is supported by the second support shaft portion 48, which is provided at the right end and rear side of the upper surface of the support body portion 42. The right end of the second link 65 engages with the engagement groove 58a of the second slider 58. The left end of the second link 65 engages with the engagement recess 71 of the first link 64. The first and second links 64 and 65 constitute a link mechanism that interlocks the first and second sliders 54 and 58. In addition, the second link 65 is provided with a cylindrical lever support shaft portion 72 on the same axis as the second support shaft portion 48.

[0055] <Manual lever> The manual lever 66 is formed in the shape of a rod bent in roughly an L-shape ("V" shape) and is connected to the upper end of the lever support shaft portion 72, which serves as the rotation axis of the second link 65. The manual lever 66 is rotated by the operator. When the operator grasps the manual lever 66 and rotates it around its axis, the first link 64 and the second link 65 rotate in opposite directions, causing the first slider 54 and the second slider 58 to move in the same direction.

[0056] <Slide drive unit> The slide drive unit 67 is connected to the color slider 56 (see Figure 4). The slide drive unit 67 includes an actuator, such as an eccentric cam rotated by a solenoid or servo motor, and is configured to push (or pull) the color slider 56 in the engagement direction D1. When the monochrome slider 55 is moved in the disengagement direction D2, the slide drive unit 67 moves only the color slider 56 in the engagement direction D1. When the slide drive unit 67 releases the pressing force (or tension) on the color slider 56, the monochrome slider 55, which has been moved in the engagement direction D1, is biased by the biasing member 60 and moves in the disengagement direction D2.

[0057] [Operation of the contact / disconnection device] Next, with reference to Figures 4 to 6, 8, 9, and 11 to 15, the operation of the connecting / detaching device 15, or in other words, the connecting / detaching operation of the developing device 22 with respect to the photoreceptor drum 20, will be explained. Figure 11 is a plan view showing the connecting / detaching device 15 (insertable / removable state). Figure 12 is a cross-sectional view taken along line XII-XII of Figure 11. Figure 13 is a right side view showing the photoreceptor drum 20, the developing device 22 (separated position P2), and the connecting / detaching device 15. Figure 14 is a plan view showing the connecting / detaching device 15 (monochrome printing state). Figure 15 is a cross-sectional view taken along line XV-XV of Figure 14.

[0058] Here, as shown in Figures 4 to 6, the initial state is defined as the position in which the gripping portion of the manual lever 66 is aligned in the front-rear direction, the first and second sliders 54 and 58 are moved in the disengagement direction D2, all developing devices 22 are positioned in the developing position P1, and all drive couplings 38 are connected to all drive transmission gears 37. In this specification, the initial state is the same as the normal printing state described later.

[0059] <When removing the developing equipment, etc.> For example, when removing the photoreceptor drum 20 or developing unit 22 from the main unit 2 for maintenance or replacement, the operator opens the cover 2A located on the right side of the main unit 2 to expose the right end surface of the photoreceptor drum 20 or developing unit 22 (see Figure 3). As shown in Figure 11, the operator grasps the manual lever 66 and pulls it towards them (to the right), rotating the manual lever 66 counterclockwise (in one direction) when viewed from above. As a result, the second link 65 rotates counterclockwise around the second support shaft 48, and the first link 64 rotates clockwise around the first support shaft 47. In other words, as the manual lever 66 rotates, the second link 65 rotates in the same direction as the manual lever 66, and the first link 64 rotates in the opposite direction to the manual lever 66 in conjunction with the second link 65.

[0060] When the manual lever 66 is rotated counterclockwise (in one direction), the first link 64 moves the monochrome slider 55 in the engagement direction D1 (from front to back) (see Figure 12), and the second link 65 moves the second slider 58 in the engagement direction D1 (see Figure 13). The color slider 56 has its front end surface in contact with the abutment step portion 55b of the slider housing portion 55a, and therefore moves together with the monochrome slider 55 in the engagement direction D1 (rearward).

[0061] When the first slider 54 (monochrome slider 55 and color slider 56) is moved in the engagement direction D1, the four first protrusions 61A to 61D contact the arm portions 52A to 52D of the corresponding release arms 50A to 50D, pushing the release arms 50A to 50D in the engagement direction D1 (rearward) (see upper part of Figure 9). The release arms 50A to 50D move parallel to the left (separation position P4) by rotating in the engagement direction D1 (counterclockwise in the upper part of Figure 9) while their arm portions 52A to 52D contact the inclined surfaces 46A to 46D. The release arms 50A to 50D make contact with the drive ribs 39A to 39D of the drive couplings 38A to 38D at their left ends, pushing the drive couplings 38A to 38D to the left and separating them from the developing rollers 31A to 31D (drive transmission gears 37A to 37D) (see the lower part of Figure 9). In this state, the connection between all developing rollers 31 and all drive input gears 36 is released, and the drive transmission to all developing rollers 31 is cut off.

[0062] After all the drive couplings 38A to 38D are separated from all the drive input gears 36A to 36D (developing rollers 31A to 31D), as shown in Figure 12, the four second protrusions 62A to 62D contact the first engaging portions 34A to 34D of the corresponding developing devices 22A to 22D, pushing the developing devices 22A to 22D in the engagement direction D1. Also, as shown in Figure 13, the four third protrusions 63A to 63D contact the second engaging portions 35A to 35D of the corresponding developing devices 22A to 22D, pushing the developing devices 22A to 22D in the engagement direction D1. Thus, when the first and second sliders 54 and 58 are moved in the engagement direction D1, the second projections 62A to 62D and the third projections 63A to 63D push the developing device 22A to 22D in the engagement direction D1, causing it to rotate from the developing position P1 to a position P2 (see Figures 12 and 13).

[0063] As a result, the image forming apparatus 1 is in an insertable / removable state with all developing devices 22 positioned at the separated position P2 (see Figures 9, 11 to 13). In the insertable / removable state, the manual lever 66 is rotated counterclockwise (one way), causing the monochrome slider 55 and the color slider 56 to move in the engagement direction D1, with all first projections 61 pushing all release arms 50, and all second projections 62 and all third projections 63 pushing all developing devices 22. After the developing devices 22 are positioned at the separated position P2 (after being put into the insertable / removable state), the operator pulls the photosensitive drum 20 and developing devices 22 to the right. The third projection 63 of the second slider 58 engages with the second engagement portion 35 of the developing device 22, guiding the developing device 22 as it is pulled out from the apparatus body 2.

[0064] <When installing developing equipment, etc.> The operator attaches (pushes in) the developing device 22 to the device body 2 in the reverse order of the procedure for removing the developing device 22 from the device body 2. At this time, the third projection 63 of the second slider 58 engages with the second engaging portion 35 of the developing device 22, guiding the developing device 22 as it is pushed into the device body 2. When the developing device 22 is positioned in the correct mounting position, the first engaging portion 34 of the developing device 22 engages with the second projection 62 of the first slider 54.

[0065] The operator grasps the manual lever 66 and pushes it to the left, rotating the manual lever 66 clockwise (in the opposite direction) when viewed from above (see Figure 4). This causes the second link 65 to rotate clockwise around the second support shaft 48, and the first link 64 to rotate counterclockwise around the first support shaft 47. When the manual lever 66 is rotated clockwise (in the opposite direction), the first link 64 moves the monochrome slider 55 in the disengagement direction D2 (from rear to front), and the second link 65 moves the second slider 58 in the disengagement direction D2. The color slider 56 is biased by the biasing member 60 and moves together with the monochrome slider 55 in the disengagement direction D2 (forward).

[0066] When the first slider 54 (monochrome slider 55 and color slider 56) and the second slider 58 are moved in the disengagement direction D2, the four second protrusions 62A to 62D and the four third protrusions 63A to 63D move away from their respective developing devices 22A to 22D in the disengagement direction D2 (forward) (see Figures 5 and 6). As a result, all developing devices 22A to 22D are biased by a return member (not shown) and rotate from the separated position P2 to the developing position P1 (see Figures 5 and 6).

[0067] After the second projection 62 and the third projection 63 move away from the developing device 22 in the disengagement direction D2, all the first projections 61A to 61D move away from their respective release arms 50A to 50D in the disengagement direction D2 (in the upper part of Figure 8, the pressure on the release arm 50 is released). As the release arms 50A to 50D rotate in the disengagement direction D2 (clockwise in the upper part of Figure 8) while contacting the inclined surfaces 46A to 46D, the drive couplings 38A to 38D are biased to the right (towards the connection position P3) by the biasing connecting members 40A to 40D and connected to the drive transmission gears 37A to 37D (see the lower part of Figure 8). As a result, the drive couplings 38A to 38D are connected to the developing rollers 31A to 31D via the drive transmission gears 37A to 37D.

[0068] As a result, the image forming apparatus 1 is in a normal printing state with all developing devices 22 positioned at the developing position P1 (see Figures 4 to 6 and 8). In the normal printing state, the manual lever 66 is rotated clockwise (the other way around), causing the monochrome slider 55 and the color slider 56 to move in the disengagement direction D2, so that all the second projections 62 and all the third projections 63 are separated from all the developing devices 22, and all the first projections 61 are separated from all the release arms 50. After the developing devices 22 are positioned at the developing position P1 (after being put into the normal printing state), the operator closes the cover 2A. This makes the image forming process ready to be performed.

[0069] <When printing monochrome images> For example, if the image data transmitted from an external terminal (such as a personal computer) is a monochrome image (an image formed using only black toner), the control unit (not shown) of the image forming apparatus 1 controls the slide drive unit 67. The cover 2A of the apparatus body 2 is closed, and the manual lever 66 is rotated clockwise (the other way around) (the manual lever 66 is not operated).

[0070] The slide drive unit 67 moves the color slider 56 in the engagement direction D1 (from front to back). At this time, as shown in Figures 14 and 15, the monochrome slider 55 remains stationary and is held in the disengagement direction D2 (forward), while only the color slider 56 moves in the engagement direction D1 (backward) against the biasing force of the biasing member 60. The second slider 58 also remains stationary and is held in the disengagement direction D2 (forward).

[0071] The three first projections 61A to 61C of the color slider 56 each push the corresponding release arms 50A to 50C in the engagement direction D1 (rearward) (see Figure 9). The three release arms 50A to 50C rotate in the engagement direction D1 (counterclockwise in the upper part of Figure 9) while contacting the inclined surfaces 46A to 46D, pushing the drive couplings 38A to 38C to the left. The drive couplings 38A to 38C separate from the developing rollers 31A to 31C (drive transmission gears 37A to 37C), releasing the connection between the developing rollers 31A to 31C and the drive input gears 36A to 36C, and interrupting the drive transmission to the developing rollers 31A to 31C (see the lower part of Figure 9). The drive coupling 38D is connected to the drive transmission gear 37D, and the drive transmission to the developing roller 31D is maintained.

[0072] After the drive couplings 38A~38C are separated from the drive input gears 36A~36C, as shown in Figure 15, the three second projections 62A~62C of the color slider 56 contact the first engagement portions 34A~34C of the corresponding developing devices 22A~22C, pushing the developing devices 22A~22D in the engagement direction D1. As a result, the second projections 62A~62C push the developing devices 22A~22C in the engagement direction D1, rotating them from the developing position P1 to the separated position P2.

[0073] As a result, the image forming apparatus 1 is in a monochrome printing state with the monochrome image developing device 22D positioned at the developing position P1 and the color image developing devices 22A to 22C positioned at the separated position P2 (see Figures 14 and 15). In the monochrome printing state, the manual lever 66 is rotated to the other side, the monochrome slider 55 moves in the disengagement direction D2 (forward), the second projection 62D of the monochrome slider 55 separates from the monochrome image developing device 22D, and the first projection 61D of the monochrome slider 55 separates from the release arm 50D. Furthermore, in monochrome printing mode, the slide drive unit 67 moves the color slider 56 in the disengagement direction D2, causing the color slider 56 to move in the engagement direction D1 (rearward), with the first projections 61A-61C of the color slider 56 pushing the release arms 50A-50C, and the second projections 62A-62C of the color slider 56 pushing the color image developing units 22A-22C. Note that in monochrome printing mode, all third projections 63 are separated from all developing units 22.

[0074] The control unit of the image forming apparatus 1 sets the device to monochrome printing mode and then performs image forming processing for the monochrome image. After the control unit finishes image forming processing for the monochrome image, it stops driving the slide drive unit 67. At this point, the color slider 56 is biased by the biasing member 60 and moves in the disengagement direction D2, returning to the normal printing mode in the reverse order of the procedure described above.

[0075] In the image forming apparatus 1 according to the embodiment described above, the developing roller 31 (developing member) is positioned offset to the right (one side in the axial direction) from the drive input gear 36 (drive input member) and is connected to the right end (one end in the axial direction) of the drive input gear 36. The connecting / disconnecting device 15 separates the developing roller 31 and the drive input gear 36 in the axial direction, then rotates the developing apparatus 22 from the developing position P1 to the separated position P2, and then rotates the developing apparatus 22 from the separated position P2 back to the developing position P1 before connecting the developing roller 31 and the drive input gear 36 in the axial direction. With this configuration, when the developing roller 31 is separated from the drive input gear 36, the developing roller 31 moves closer to or further away from the photoreceptor drum 20, so the developing apparatus 22 can be swung even if the developing roller 31 and the drive input gear 36 are aligned in the axial direction. Furthermore, since the contact / detachment device 15 combines the functions of oscillating the developing device 22 and switching the drive input of the developing roller 31, the structure of the image forming apparatus 1 can be simplified and manufacturing costs reduced compared to the case where the mechanism for oscillating the developing device 22 and the mechanism for switching the drive input of the developing roller 31 are provided separately.

[0076] Furthermore, in the image forming apparatus 1 according to this embodiment, the connecting / disconnecting device 15 is configured to switch between one of the following states: an insertable / removable state in which all developing devices 22 are positioned at the separated position P2, a normal printing state in which all developing devices 22 are positioned at the developing position P1, and a monochrome printing state in which the developing device 22D for monochrome images is positioned at the developing position P1 and the developing devices 22A to 22C for color images are positioned at the separated position P2. With this configuration, by setting the image forming apparatus 1 to the monochrome printing state, the developing rollers 31A to 31C for color images can be stopped at a distance from the photoreceptor drums 20A to 20C, and only the developing roller 31D for monochrome images can be rotated in close proximity to the photoreceptor drum 20D. This prevents the developing rollers 31A to 31C for color images and the photoreceptor drums 20A to 20C from rotating relative to each other and deteriorating when forming a monochrome image, and also prevents the developer (toner) contained in the developing devices 22A to 22C for color images from rubbing against each other and deteriorating.

[0077] Furthermore, in the image forming apparatus 1 according to this embodiment, the developing roller 31 is connected to the drive input gear 36 via a drive coupling 38, and the forward / backward movement (toward / away direction) of the first slider 54 is converted into the rotation of the release arm 50, and the release arm 50 rotates while contacting the inclined surface portion 46, thereby moving the drive coupling 38 in the left / right direction (axial direction). In addition, after the drive coupling 38 separates from the developing roller 31, the second projection 62 of the first slider 54 pushes the developing device 22 toward the separated position P2. Furthermore, after the second projection 62 of the first slider 54 separates from the developing device 22 and the developing device 22 moves to the developing position P1, the drive coupling 38 is connected to the developing roller 31. With this configuration, the oscillation of the developing device 22 and the switching operation of the drive input of the developing roller 31 can be properly linked. As a result, the developing device 22 can be oscillated even if the developing roller 31, drive coupling 38 and drive input gear 36 are aligned in the axial direction.

[0078] Furthermore, according to the image forming apparatus 1 of this embodiment, since the developing device 22 is positioned between the first slider 54 and the second slider 58, the second and third projections 62 and 63 can be pressed against both ends of the developing device 22 in the left-right direction (axial direction). This ensures stable rotation of the developing device 22. Also, in the removable state, all developing devices 22 are engaged with the third projection 63 of the second slider 58, so all developing devices 22 can be pulled out straight while being guided by the third projection 63. This suppresses problems such as the developing roller 31 coming into contact with the photosensitive drum 20 during the process of pulling out the developing device 22 from the apparatus body 2.

[0079] Furthermore, in the image forming apparatus 1 according to this embodiment, the first slider 54 and the second slider 58 were connected via a link mechanism including first and second links 64 and 65. With this configuration, by rotating the manual lever 66, the first link 64 and the second link 65 rotate in opposite directions, causing the first slider 54 and the second slider 58 to move in the same direction in conjunction with each other.

[0080] In the image forming apparatus 1 according to this embodiment, the developing roller 31 was connected to the drive input gear 36 (drive motor) via a drive coupling 38, but the present invention is not limited thereto. For example, the drive coupling 38 may be omitted, and the developing roller 31 may be directly connected to the drive input gear 36 (drive motor) (not shown). In this case, the drive input gear 36 may be provided to be movable in the axial direction.

[0081] Furthermore, in the image forming apparatus 1 according to this embodiment, the operator manually operates a manual lever 66 to slide the first and second sliders 54 and 58, switching between the insertable / removable state and the normal printing state. However, the present invention is not limited to this. For example, a drive source (not shown) for sliding the first and second sliders 54 and 58 may be provided, and the control unit may drive the drive source based on terminal operation by the operator, causing the first and second sliders 54 and 58 to slide in conjunction. In this case, the first and second links 64 and 65 and the manual lever 66 may be omitted (not shown).

[0082] Furthermore, in the image forming apparatus 1 according to this embodiment, the developing roller 31 and the drive input gear 36 are separated or connected by the rotation (oscillation) of the release arm 50, but the present invention is not limited thereto. For example, the release arm 50 may be omitted, and a drive source (not shown) that reciprocates the drive coupling 38 (or drive input gear 36) in the axial direction may be provided, and the control unit may drive and control the drive source to separate or connect the developing roller 31 and the drive input gear 36.

[0083] Furthermore, in the image forming apparatus 1 according to this embodiment, the first slider 54 and the second slider 58 are provided so as to sandwich the developing apparatus 22 from both sides in the axial direction, but the present invention is not limited to this. For example, the second slider 58 may be omitted, and the developing apparatus 22 may be oscillated by the first slider 54 (not shown).

[0084] Furthermore, in the image forming apparatus 1 according to this embodiment, the pivot axis 33 of the developing apparatus 22 was positioned radially offset from the developing roller 31, but the present invention is not limited to this. For example, the pivot axis 33 may be positioned on the same axis as the developing roller 31 or the drive input gear 36 (drive transmission gear 37) (not shown). In other words, the rotation axis of the developing roller 31 or the drive input gear 36 (drive transmission gear 37) may be the pivot axis 33. In this case, when the developing apparatus 22 is oscillated, it is not necessary to separate the developing roller 31 and the drive input gear 36, and the drive coupling 38, release arm 50, etc. may be omitted (not shown).

[0085] Furthermore, while the above description of the embodiments shows the application of the present invention to an image forming apparatus 1 (printer) as an example, the invention is not limited to this, and may also be applied to, for example, a copier, facsimile machine, or multifunction device.

[0086] The above description of the embodiments illustrates one aspect of the image forming apparatus according to the present invention, and the technical scope of the present invention is not limited to the above embodiments. The present invention may be modified, substituted, or transformed in various ways without departing from the spirit of the technical idea, and the claims include all embodiments that may fall within the scope of the technical idea. [Explanation of Symbols]

[0087] 1. Image forming apparatus 2. Main unit of the device 15 Disconnection device 20 Photosensitive drum (image carrier) 22 Developing equipment 31. Developing roller (developing component) 33. Oscillating axis 36 Drive input gear (drive input component) 38 Drive Coupling 41 Support member 46 Slope section 48 Second support shaft (rotation shaft) 50 Release Arm 54. First slider 58. Second slider 55 Monochrome Slider 56 Color Sliders 60 biasing member 61 1st protrusion 62 2nd protrusion 63 Third protrusion 64. Link 1 65 Second Link 66 Manual lever 67 Slide drive unit P1 development position P2 Separate position

Claims

1. An image carrier is mounted on the device body so as to be movable in the axial direction, and carries the latent image while rotating around the axis, A developing device having a developing member that rotates around an axis while approaching or in contact with the image carrier to develop the latent image, mounted on the main body of the device so as to be movable in the axial direction, and rotating around a pivot axis arranged parallel to the developing member, A developing device that rotates the developing device between a developing position in which the developing member is brought close to or in contact with the image carrier, and a separating position in which the developing member is separated from the image carrier, The device comprises a drive input member that is rotatably supported on the axis of the contact / disconnection device and inputs a driving force to the developing member, Multiple image carriers, developing devices, and drive input members are provided, each corresponding to monochrome images and color images. The multiple image carriers, the multiple developing devices, and the multiple drive input members are each arranged in a line in a direction perpendicular to the axial direction, The image carrier and the developing device are removable from the main body of the device in one direction in the axial direction when the developing device is positioned at the separated position. The developing member is positioned offset from the drive input member in one axial direction and connected to one end of the drive input member in the axial direction. The aforementioned connecting / disconnecting device is After separating the developing member and the drive input member in the axial direction, the developing device is rotated from the developing position to the separated position. After rotating the developing device from the separated position to the developing position, the developing member and the drive input member are connected in the axial direction. The aforementioned connecting / disconnecting device is All of the developing devices are in an insertable and removable state with the separated positions, A normal printing state in which all the developing devices are placed in the developing position, An image forming apparatus characterized by switching to one of the following states: a monochrome printing state in which the developing device for monochrome images is placed at the developing position and the developing device for color images is placed at the separated position.

2. The developing member approaches or contacts the image carrier from one of the moving-away directions and is connected to one end of the drive input member in the axial direction via a cylindrical drive coupling. The aforementioned connecting / disconnecting device is A support member that supports the drive coupling so that it is rotatable and movable in the axial direction, Multiple release arms are provided so as to be rotatable along the outer circumferential surface of the drive coupling and move in the axial direction by rotating while contacting an inclined surface formed on the support member, It includes a first slider that is movable between an engagement direction, which is one of the aforementioned connecting and disconnecting directions, and a disengagement direction, which is the other of the connecting and disconnecting directions, The first slider includes a monochrome slider corresponding to the developing apparatus for monochrome images and a color slider corresponding to the developing apparatus for color images. The monochrome slider and the color slider each have a first projection that is provided so as to be able to contact the release arm and a second projection that is provided so as to be able to contact the developing device. When the first slider is moved in the engagement direction, the first projection pushes the release arm in the engagement direction, causing the release arm to rotate in the engagement direction while contacting the inclined surface, thereby separating the drive coupling from the developing member, and then the second projection pushes the developing device in the engagement direction, causing it to rotate from the developing position to the separated position. When the first slider is moved in the disengagement direction, the second projection moves away from the developing device in the disengagement direction, the developing device rotates from the separated position to the developing position, and thereafter the first projection moves away from the release arm in the disengagement direction, and the release arm rotates in the disengagement direction while contacting the inclined surface, thereby connecting the drive coupling to the developing member. In the aforementioned removable state, the monochrome slider and the color slider move in the engagement direction, all of the first projections push all of the release arms, and all of the second projections push all of the developing device. In the normal printing state, the monochrome slider and the color slider move in the disengagement direction, all of the second protrusions move away from all of the developing device, and all of the first protrusions move away from all of the release arms. The image forming apparatus according to claim 1, characterized in that, in the monochrome printing state, the monochrome slider moves in the disengagement direction, the second projection of the monochrome slider separates from the developing device for the monochrome image, the first projection of the monochrome slider separates from the release arm, the color slider moves in the engagement direction, the first projection of the color slider pushes the release arm, and the second projection of the color slider pushes the developing device for the color image.

3. The connecting / disconnecting device further includes a second slider that is provided to be movable between the engagement direction and the disengagement direction in conjunction with the first slider, The first slider and the release arm are provided on the other side of the support member in the axial direction. The second projection contacts the other end of the developing device in the axial direction, The second slider is provided on one side of the support member in the axial direction and has a third projection that is provided so as to be able to contact one end of the developing device in the axial direction. When the first slider and the second slider are moved in the engagement direction, the drive coupling separates from the developing member, and then the second projection and the third projection push the developing device in the engagement direction, causing it to rotate from the developing position to the separated position. When the first slider and the second slider are moved in the disengagement direction, the second projection and the third projection move away from the developing device in the disengagement direction, after which the drive coupling connects to the developing member. In the aforementioned removable state, all of the third projections push all of the developing device and guide the developing device as it is pulled out from the main body of the device. The image forming apparatus according to claim 2, characterized in that in the normal printing state and the monochrome printing state, all of the third protrusions are spaced apart from all of the developing device.

4. The aforementioned connecting / disconnecting device is A first link is rotatably supported by the support member and engages with the monochrome slider, A second link is rotatably supported by the support member and engages with the first link and the second slider, A manual lever connected to the rotating shaft of the second link, A slide drive unit that moves the color slider in the engagement direction, The system further includes a biasing member that biases the color slider toward the disengagement direction, As the manual lever rotates, the second link rotates in the same direction as the manual lever, and the first link rotates in the opposite direction to the manual lever in conjunction with the second link. When the manual lever is rotated to one side, the first link moves the monochrome slider together with the color slider in the engagement direction, and the second link moves the second slider in the engagement direction. When the manual lever is rotated to the other side, the first link moves the monochrome slider in the disengagement direction, the biasing member moves the color slider in the disengagement direction, and the second link moves the second slider in the disengagement direction. In the aforementioned insertion / removal state, the manual lever is rotated to one side. In the normal printing state, the manual lever is rotated to the other side. The image forming apparatus according to claim 3, characterized in that, in the monochrome printing state, the manual lever is rotated to the other, the slide drive unit moves the color slider in the disengagement direction, the first projection of the color slider pushes the release arm, and the second projection of the color slider pushes the developing device for the color image.

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