JP6555216B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  2. Description of the Related Art Conventionally, an image forming apparatus that forms an image on a sheet includes an apparatus main body, a photosensitive drum (image carrier), and a developing device. The developing device includes a developing roller that faces the photosensitive drum. Patent Document 1 discloses a technique in which a developing device can be attached to and detached from an apparatus main body.

  The developing device is attached to and detached from the apparatus main body as an image forming unit. The apparatus main body includes a rail member and a notch formed at one end of the rail member. On the other hand, the image forming unit includes a rotatable roller that rolls on the rail member. When the image forming unit is mounted, the roller is removed from the rail member and enters the notch, whereby the image forming unit is positioned at a predetermined position in the apparatus main body.

JP 2012-230280 A

  In the image forming apparatus described in Patent Document 1, when the image forming unit is detached from the apparatus main body, the roller needs to be detached upward from the notch. For this reason, the operator needs to pull the image forming unit upward and then pull it out from the main body of the apparatus, and there is a problem that the operability of attaching and detaching the image forming unit becomes complicated.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of easily and reliably performing positioning and attachment / detachment of an image forming unit.

An image forming apparatus according to an aspect of the present invention is disposed in an apparatus main body, an image forming unit that can be attached to and detached from the apparatus main body along a predetermined attaching / detaching direction, and the image forming apparatus. A guide portion that guides attachment and detachment of the unit; a first urging member that is disposed in the guide portion; and a unit abutting portion that abuts on the image forming unit by receiving the urging force of the first urging member. A positioning mechanism for biasing the image forming unit mounted at a first position in the apparatus main body to position the image forming unit; and a swingable mechanism provided in the image forming unit. A first posture in which the image forming unit is locked in the first position, the lock of the image forming unit is released, and the image forming unit is along the attaching / detaching direction. A lever member that can be changed in posture between a second posture that allows detachment from the apparatus main body, and the guide portion guides the image forming unit; and the guide An engaged portion disposed on the front side in the mounting direction of the image forming unit from the surface, the lever member includes a fulcrum portion serving as a fulcrum in the swing, and the image forming unit is separated from the apparatus main body. In order to be detached, the pressed portion to be pressed, and disposed on the opposite side of the pressed portion with respect to the fulcrum portion, can be rotated around the fulcrum portion, and the engaged portion of the guide portion A hook that can be engaged with a joint part, and a contact part that is disposed between the fulcrum part and the pressed part and that can contact the guide surface of the guide part, wherein the contact part is , Arranged at a first distance with respect to the fulcrum part, A first contact portion that contacts the guide surface in a state where the hook of the lever member in the first posture is engaged with the engaged portion and the image forming unit is locked at the first position. When the pressed portion of the lever member is pressed while the image forming unit is locked at the first position, the lever member rotates around the fulcrum portion and the hook and the covered portion The engagement with the engagement portion is released, the first contact portion serves as a fulcrum, and the fulcrum portion serves as a load point. The image forming unit moves upward against the urging force of the first urging member. The first distance of the first contact portion is set so that the image forming unit is pushed up and the positioning of the image forming unit by the positioning mechanism is released.

  According to this configuration, the lever member can be changed in posture between the first posture and the second posture by being swung. When the hook of the lever member is engaged with the engaged portion of the guide portion, the image forming unit is locked at the first position. Further, when the pressed portion of the lever member is pressed, the lock of the image forming unit is released and the image forming unit is allowed to be detached from the apparatus main body along a predetermined attaching / detaching direction. As a result, it is possible to easily and reliably execute positioning and detachment of the image forming unit. Further, when the operator presses the lever member, since the first contact portion is in contact with the guide surface, a predetermined pressing load is generated on the lever member. For this reason, compared with the case where there is play in the lever member, the occurrence of work mistakes by the operator is suppressed. Further, since the first contact portion functions as a fulcrum, positioning by the positioning mechanism can be easily released against the biasing force of the first biasing member. Further, the hook is rotatable around the fulcrum portion. For this reason, when the image forming unit is mounted at the first position, even if the hook and the contact portion simultaneously contact the engaged portion and the guide surface, respectively, the image is rotated by the rotation of the hook. Installation of the forming unit is realized smoothly.

  In the above-described configuration, it is preferable to further include a second urging member that urges the hook in the first rotation direction around the fulcrum so that the hook engages with the engaged portion.

  According to this configuration, the hook can be maintained in the posture of engaging with the engaged portion by the biasing force of the second biasing member. For this reason, the engagement between the hook and the engaged portion is prevented from being erroneously released.

  In the above configuration, the lever member may be configured such that the hook is integrated with the pressed portion when the pressed portion is rotated around the fulcrum in a second rotation direction opposite to the first rotation direction. It is desirable to further have an interlocking part that rotates the target.

  According to this configuration, even when the hook is rotatable around the fulcrum portion, the engagement between the hook and the engaged portion can be smoothly released in accordance with the pressed operation of the lever member.

  In the above configuration, the contact portion is further disposed at a second distance larger than the first distance with respect to the fulcrum portion on the pressed portion side with respect to the first contact portion. A positioning mechanism that includes a second abutting portion that is capable of abutting on the guide surface and that is spaced apart from the guide surface in a state in which the image forming unit is locked at the first position. When the pressed part is further pressed after the positioning by the step is released, the second contact part comes into contact with the guide surface, the second contact part serves as a fulcrum, and the fulcrum part serves as a load point. The image forming unit receives the urging force of the first urging member and reaches a second position above the first position, and the image forming unit is detached from the apparatus main body along the attaching / detaching direction. So that the second abutment portion can be separated. It is desirable to serial second distance is set.

  According to this configuration, since the lever ratio of the second contact portion is set smaller than that of the first contact portion, when the image forming unit is pushed up while receiving the biasing force of the first biasing member, The pressing force required for the person can be reduced.

  In the above configuration, when viewed in a cross section perpendicular to the axial direction of the fulcrum portion, the contact portion has an arc shape, and the first contact portion and the second contact portion are formed by the arc. It is desirable to be connected.

  According to this configuration, the operator can smoothly unlock the image forming unit and move from the first position to the second position by continuously pressing the lever member.

  In the above configuration, the unit contact portion of the positioning mechanism includes a tapered tip portion along a mounting direction of the image forming unit with respect to the apparatus main body, and the image forming unit is pressed by the unit contact portion. When the image forming unit is pushed up against the urging force of the first urging member. The unit pressed portion moves over the tip end portion of the unit abutting portion while compressing the first urging member, so that the positioning of the image forming unit by the positioning mechanism is released and the unit contact portion The image arranged at the first position so that the contact portion receives the urging force of the first urging member to promote the pushing-up of the image forming unit. That the unit pressed portion of the deposition unit is arranged to face the unit abutting portion is preferable.

  According to this configuration, the movement of the unit pressed portion of the image forming unit can release the positioning by the positioning mechanism and promote the movement of the image forming unit.

  In the above configuration, the image forming unit further includes an image carrier that is rotatably arranged on the apparatus main body and forms an electrostatic latent image on a peripheral surface thereof, and the image forming unit supplies developer to the image carrier. A developing device including a developing roller, wherein the positioning mechanism urges the image forming unit in a direction in which the developing roller approaches the image carrier, and the image forming unit is disposed in the main body of the device. When positioned at the first position, it is desirable that the developing roller is disposed at a predetermined interval with respect to the image carrier.

  According to this configuration, the developing roller is arranged at a predetermined interval with respect to the image carrier by the positioning mechanism. For this reason, the electrostatic latent image on the image carrier is stably developed by the developing roller.

  In the above configuration, it is preferable that the developing device includes an interval holding member that is disposed at both end portions in the axial direction of the developing roller and contacts the circumferential surface of the image carrier.

  According to this configuration, the interval between the developing roller and the image carrier is stably held by the interval holding member.

  In the above-described configuration, the image forming unit further includes a developer container that can be attached to and detached from the developing device and can be attached to and detached from the device main body integrally with the developing device. Is desirable.

  According to this configuration, it is possible to easily and reliably execute the positioning and the detachment of the developing device even when the developer container is mounted on the developing device.

  According to the present invention, an image forming apparatus capable of easily and reliably executing positioning and detachment of an image forming unit is provided.

1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. 1 is an internal cross-sectional view of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view of an image forming unit and a guide unit according to an embodiment of the present invention. FIG. 3 is a perspective view of a developer container according to an embodiment of the present invention. 1 is a perspective view of a developing device according to an embodiment of the present invention. FIG. 3 is a top view of a part of the image forming unit according to the embodiment of the present invention. It is sectional drawing of the image forming unit and guide part which concern on one Embodiment of this invention, Comprising: It is a figure which shows a mode that a lever member is pressed. It is sectional drawing of the image forming unit and guide part which concern on one Embodiment of this invention, Comprising: It is a figure which shows a mode that a lever member is pressed. It is sectional drawing of the image forming unit and guide part which concern on one Embodiment of this invention, Comprising: It is a figure which shows a mode that a lever member is pressed. FIG. 3 is a cross-sectional view of an image forming unit and a guide unit according to an embodiment of the present invention, and is a diagram illustrating a state in which the image forming unit is positioned by a positioning mechanism. FIG. 5 is a cross-sectional view of the image forming unit and the guide unit according to the embodiment of the present invention, and shows a state in which the positioning of the image forming unit by the positioning mechanism is released. It is a disassembled perspective view of the lever member which concerns on one Embodiment of this invention. It is a disassembled perspective view of the lever member which concerns on one Embodiment of this invention. It is a perspective view of the lever member concerning one embodiment of the present invention. It is a perspective view of the lever member concerning one embodiment of the present invention. FIG. 2 is an exploded perspective view of an image forming unit and a lever member according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of an image forming unit and a lever member according to an embodiment of the present invention. It is sectional drawing of the image forming unit and guide part which concern on one Embodiment of this invention, Comprising: It is a figure which shows a mode that the hook rotated. FIG. 5 is a cross-sectional view of an image forming unit and a guide unit in another image forming apparatus compared with the image forming apparatus according to the embodiment of the present disclosure. FIG. 5 is a cross-sectional view of an image forming unit and a guide unit in another image forming apparatus compared with the image forming apparatus according to the embodiment of the present disclosure. FIG. 5 is a cross-sectional view of an image forming unit and a guide unit in another image forming apparatus compared with the image forming apparatus according to the embodiment of the present disclosure.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a printer 100 (image forming apparatus) according to the present embodiment. FIG. 2 is a cross-sectional view schematically showing the internal structure of the printer 100. The printer 100 shown in FIGS. 1 and 2 is a so-called monochrome printer, but in other embodiments, the image forming apparatus is a color printer, a facsimile machine, a multifunction machine having these functions, or a toner image on a sheet. Other devices for forming may be used. Note that the terms used in the following description, such as “up”, “down”, “front”, “rear”, “left” and “right”, are merely for the purpose of clarifying the description. There is no limitation on the principle of the image forming apparatus.

  The printer 100 includes a housing 101 (apparatus main body) that houses various apparatuses for forming an image on the sheet S. The housing 101 includes an upper wall 102 that defines the upper surface of the housing 101, a bottom wall 103 that defines the bottom surface of the housing 101, a main body rear wall 105 between the upper wall 102 and the bottom wall 103, and a rear body. And a main body front wall 104 positioned in front of the wall 105. The housing 101 includes a main body internal space 107 in which various devices are arranged. A sheet conveyance path PP through which the sheet S is conveyed in a predetermined conveyance direction is extended in the main body internal space 107 of the casing 101. Moreover, the housing | casing 101 is provided with a pair of left wall 101L and right wall 101R (FIG. 1). The left wall 101L and the right wall 101R are wall portions that form the left and right side surfaces of the housing 101.

  A paper discharge unit 102 </ b> A is disposed at the center of the upper wall 102. The paper discharge unit 102 </ b> A includes an inclined surface that is inclined downward from the front portion to the rear portion of the upper wall 102. The sheet S on which an image is formed in the image forming unit 120 described later is discharged to the paper discharge unit 102A. A front cover 106 including a manual feed tray 104A is disposed on the main body front wall 104. The front cover 106 can be turned up and down with the lower end as a fulcrum (arrow DT in FIG. 2). On the other hand, the front end 102B of the upper wall 102 can be rotated rearward with the arm 108 as a fulcrum (FIG. 1). As shown in FIG. 1, when the front end portion 102 </ b> B and the front cover 106 of the upper wall 102 are opened, the main body internal space 107 is exposed to the outside of the printer 100. As a result, an image forming unit 120H, which will be described later, can be mounted inside the housing 101. Further, when the sheet S is jammed in the sheet conveyance path PP, the sheet S can be removed.

  Referring to FIG. 2, the printer 100 includes a cassette 110, a pickup roller 112, a first paper feed roller 113, a second paper feed roller 114, a transport roller 115, a registration roller pair 116, and an image forming unit. 120 and a fixing device 130.

  The cassette 110 accommodates the sheet S inside. The cassette 110 includes a lift plate 111. The lift plate 111 is inclined so as to push up the leading edge of the sheet S. The cassette 110 can be pulled forward with respect to the housing 101.

  The pickup roller 112 is disposed on the leading edge of the sheet S pushed up by the lift plate 111. When the pickup roller 112 rotates, the sheet S is pulled out from the cassette 110.

  The first paper feed roller 113 is disposed downstream of the pickup roller 112 and sends the sheet S further downstream. The second paper feed roller 114 is disposed on the inner side (rear side) of the fulcrum of the manual feed tray 104A, and draws the sheet S on the manual feed tray 104A into the housing 101.

  The conveyance roller 115 is disposed downstream (hereinafter also simply referred to as downstream) of the first paper supply roller 113 and the second paper supply roller 114 in the sheet conveyance direction (hereinafter also simply referred to as conveyance direction). The transport roller 115 transports the sheet S sent out by the first paper feed roller 113 and the second paper feed roller 114 further downstream.

  The registration roller pair 116 has a function of correcting the oblique conveyance of the sheet S. Thereby, the position of the image formed on the sheet S is adjusted. The registration roller pair 116 supplies the sheet S to the image forming unit 120 in accordance with the timing of image formation by the image forming unit 120.

  The image forming unit 120 includes a photosensitive drum 121 (image carrier), a charger 122, an exposure device 123, a developing device 20, a toner container 30 (developer storage container), a transfer roller 126, and a cleaning device. 127. As will be described later, the developing device 20 and the toner container 30 can be integrally attached to and detached from the housing 101 as the image forming unit 120H.

  The photosensitive drum 121 has a cylindrical shape and is rotatably supported by the housing 101. The photosensitive drum 121 has a peripheral surface on which an electrostatic latent image is formed, and carries a toner image (developer image) corresponding to the electrostatic latent image on the peripheral surface. The charger 122 is applied with a predetermined voltage and charges the peripheral surface of the photosensitive drum 121 substantially uniformly.

  The exposure device 123 irradiates the peripheral surface of the photosensitive drum 121 charged by the charger 122 with laser light. The laser light is emitted in accordance with image data output from an external device (not shown) such as a personal computer connected to the printer 100 so as to be communicable. As a result, an electrostatic latent image corresponding to the image data is formed on the peripheral surface of the photosensitive drum 121.

  The developing device 20 supplies toner (developer) to the peripheral surface of the photosensitive drum 121 on which the electrostatic latent image is formed. The toner container 30 supplies toner to the developing device 20. The toner container 30 is detachably disposed with respect to the developing device 20. When the developing device 20 supplies toner to the photosensitive drum 121, the electrostatic latent image formed on the peripheral surface of the photosensitive drum 121 is developed (visualized). As a result, a toner image (developer image) is formed on the peripheral surface of the photosensitive drum 121.

  The transfer roller 126 is disposed below the photosensitive drum 121 so as to face the photosensitive drum 121 with the sheet conveyance path PP interposed therebetween. The transfer roller 126 forms a transfer nip portion with the photosensitive drum 121 and transfers the toner image onto the sheet S.

  The cleaning device 127 removes the toner remaining on the peripheral surface of the photosensitive drum 121 after the toner image is transferred to the sheet S.

  The fixing device 130 is disposed downstream of the image forming unit 120 in the transport direction, and fixes the toner image on the sheet S. The fixing device 130 includes a heating roller 131 that melts the toner on the sheet S and a pressure roller 132 that causes the sheet S to adhere to the heating roller 131.

  The printer 100 further includes a transport roller pair 133 disposed downstream of the fixing device 130 and a discharge roller pair 134 disposed downstream of the transport roller pair 133. The sheet S is conveyed upward by the conveyance roller pair 133 and is finally discharged from the housing 101 by the discharge roller pair 134. The sheets S discharged from the housing 101 are stacked on the paper discharge unit 102A.

  Next, the image forming unit 120H (the developing device 20 and the toner container 30) according to the present embodiment will be described in detail with reference to FIGS. FIG. 3 is a perspective view of the image forming unit 120H according to the present embodiment and a main body unit 150 (guide portion) described later. FIG. 4 is a perspective view of the toner container 30 according to the present embodiment. FIG. 5 is a perspective view of the developing device 20 according to the present embodiment. FIG. 6 is a top view of a part of the image forming unit 120H.

  7 to 9 are cross-sectional views of the image forming unit 120H and the main body unit 150, showing a state in which the lock lever 50 described later is pressed. 10 and 11 are cross-sectional views of the image forming unit 120H and the main unit 150 according to the present embodiment, and FIG. 10 is a diagram illustrating a state in which the image forming unit 120H is positioned by the positioning mechanism 150S. FIG. 11 is a diagram illustrating a state in which the positioning of the image forming unit 120H by the positioning mechanism 150S has been released. 7 to 9 correspond to the cross-sectional view taken along the line XX in FIG. 6, and the cross-sectional views shown in FIGS. 10 and 11 correspond to the cross-sectional view taken along the line YY in FIG. To do.

  As described above, the image forming unit 120H (FIG. 3) includes the developing device 20 and the toner container 30. The image forming unit 120H can be attached to and detached from the housing 101 along a predetermined attachment / detachment direction. As a result, the toner container 30 can be attached to the housing 101 integrally with the developing device 20. When the developing device 20 is mounted on the housing 101 first, the toner container 30 is mounted alone on the developing device 20 in the housing 101. 2 and 3 indicate the mounting direction of the image forming unit 120H with respect to the housing 101.

  Furthermore, the printer 100 includes a main unit 150 (guide unit) (FIGS. 3 and 7). The main unit 150 is disposed in the housing 101 and guides the attachment / detachment of the image forming unit 120H. As shown in FIG. 1, when the front cover 106 is opened with respect to the housing 101, the main unit 150 is exposed to the outside of the housing 101. The image forming unit 120H is mounted in the main body internal space 107 of the housing 101 so as to pass above the main unit 150. As shown in FIG. 3, the main unit 150 is a unit that has a substantially triangular shape in a side view and extends long in the left-right direction. The main unit 150 includes a positioning mechanism 150S (FIG. 10), an engaged portion 153 (FIGS. 3 and 7), and a guide surface 154 (FIG. 7).

  A pair of positioning mechanisms 150 </ b> S are disposed at both left and right ends of the main unit 150. The positioning mechanism 150S includes an urging protrusion 151 (unit contact portion) and a unit urging spring 152 (first urging member). The biasing protrusion 151 abuts against the housing pressed portion 200K (FIG. 10) of the image forming unit 120H mounted on the housing 101. As shown in FIG. 10, the biasing protrusion 151 has a tapered tip along the mounting direction of the image forming unit 120 </ b> H with respect to the housing 101. The unit biasing spring 152 biases the biasing protrusion 151 rearward. In other words, the unit urging spring 152 urges the image forming unit 120H mounted at the first position described later in the housing 101 rearward to position the image forming unit 120H.

  The guide surface 154 (FIG. 7) is formed on the upper surface portion of the main body unit 150. The guide surface 154 has a function of guiding the mounting of the image forming unit 120H. The guide surface 154 includes an inclined surface that descends from the front toward the rear. Further, the rear end side of the inclined surface of the guide surface 154 is a horizontal surface. The engaged portion 153 is disposed on the tip side of the mounting direction of the image forming unit 120H (the direction of the arrow DA in FIG. 3) with respect to the guide surface 154. A hook 506 (FIG. 7) of the lock lever 50 described later can be engaged with the engaged portion 153.

  Referring to FIG. 4, toner container 30 contains toner (developer) therein. The toner container 30 includes a container main body 30A, a container lid 30B, and a container cover 30C. The container body 30A has a shape extending in the left-right direction (longitudinal direction). The upper surface portion of the container main body 30A is opened.

  The container lid 30B is fixed to the container main body 30A so as to close the opening of the container main body 30A. In the present embodiment, the container lid 30B is welded and fixed to the container main body 30A. The container lid 30B includes a first grip 32, a second grip 33, and a third grip 36. When the toner container 30 is mounted on the developing device 20 or when the image forming unit 120H including the toner container 30 and the developing device 20 is mounted on the housing 101, the operator The two gripping portions 33 or the first gripping portion 32 and the third gripping portion 36 can be gripped.

  The container cover 30C is attached to the right side portion of the container main body 30A. The container cover 30C includes a container guide 31. The container guide 31 is a substantially rectangular parallelepiped guide protruding from the container cover 30C. Although not shown in FIG. 4, a guide having the same shape as the container guide 31 is also provided on the left side of the toner container 30. These guides guide the mounting of the toner container 30 to the developing device 20.

  Further, the toner container 30 includes a conveying screw 34 and a stirring paddle 35 (FIG. 10).

  The conveying screw 34 is a screw arranged along the bottom of the container main body 30A. A toner discharge port (not shown) is opened at the bottom of the container main body 30A. The conveying screw 34 is rotated to convey the toner in the container main body 30A toward the toner discharge port. When a shutter (not shown) provided in the container main body 30 </ b> A slides, the toner discharge port is opened, and the toner can be discharged from the toner container 30. The agitation paddle 35 is rotatably supported inside the toner container 30 and agitates the toner accommodated in the toner container 30.

  The developing device 20 includes a developing housing 200 (FIG. 3), a developing roller 210 (FIGS. 3 and 10), a contact roller 211 (FIG. 3) (interval holding member), and a first screw 212 (FIG. 10). , A second screw 213 (FIG. 10), a layer thickness regulating member 214 (FIG. 10), and a developing roller cover 215.

  The developing housing 200 is a housing that supports each member of the developing device 20. The developing housing 200 has a function of supporting the toner container 30. Referring to FIG. 5, the developing housing 200 includes a housing left wall 200L, a housing right wall 200R, and a toner supply port 200H. The housing left wall 200 </ b> L and the housing right wall 200 </ b> R are wall portions erected from both ends in the left-right direction of the developing housing 200. The toner container 30 is mounted between the housing left wall 200L and the housing right wall 200R. Further, the developing housing 200 includes a housing pressed portion 200K (FIG. 10). The housing pressed portion 200K is pressed by the biasing protrusion 151 of the positioning mechanism 150S.

  The housing right wall 200R includes a right guide portion 200R1, a lock piece 200R2, and a press button 200R3. The housing left wall 200L includes a left guide portion 200L1. The right guide portion 200R1 and the left guide portion 200L1 are guide grooves formed in the housing right wall 200R and the housing left wall 200L, respectively. These guide portions are formed along the mounting direction of the toner container 30 with respect to the developing housing 200 (arrow DC1 in FIG. 5). The aforementioned container guide 31 (FIG. 4) of the toner container 30 enters the right guide portion 200R1. Further, a guide (not shown) provided on the left side surface of the toner container 30 enters the left guide portion 200L1. The toner container 30 is inserted above the developing housing 200 and then rotated in the direction of arrow DC2 in FIG. As a result, a toner discharge port (not shown) of the toner container 30 faces the toner supply port 200H, and toner can be supplied from the toner container 30 to the developing device 20. Lock piece 200R2 locks toner container 30 rotated in the direction of arrow DC2. Further, when the press button 200R3 is pressed, the lock of the toner container 30 is released, and the toner container 30 is rotated in the direction opposite to the arrow DC2 direction in FIG. As a result, the toner container 30 can be detached from the developing device 20 along the direction opposite to the arrow DC1.

  The developing roller 210 is rotatably supported by the developing housing 200. The developing roller 210 carries a developer composed of toner and carrier on the peripheral surface. The developing roller 210 supplies toner to the photosensitive drum 121 and develops the electrostatic latent image on the photosensitive drum 121. A pair of contact rollers 211 are arranged at both ends of the developing roller 210 in the axial direction. The contact roller 211 is in contact with the peripheral surface of the photoconductive drum 121, thereby maintaining a constant distance between the developing roller 210 and the photoconductive drum 121. The first screw 212 and the second screw 213 are screws that are rotatably supported in the developing housing 200. The developer in the developing housing 200 is circulated and conveyed by the first screw 212 and the second screw 213. Further, the developer is supplied to the developing roller 210 by the first screw 212. The layer thickness regulating member 214 regulates the layer thickness of the developer supplied on the developing roller 210. The developing roller cover 215 can swing with respect to the developing housing 200. FIG. 3 shows a state in which the developing roller cover 215 is retracted above the developing roller 210. When the developing roller cover 215 is swung downward from the state shown in FIG. 3, the developing roller cover 215 can cover the developing roller 210. Therefore, when the image forming unit 120H is detached from the housing 101, foreign matters are prevented from adhering to the developing roller 210 and the surroundings are prevented from being stained by the toner on the developing roller 210.

  Further, the developing device 20 includes a lock lever 50 (lever member) (FIGS. 3 and 5). The lock lever 50 is swingably provided on the housing left wall 200L of the developing device 20. The lock lever 50 unlocks the image forming unit 120H in the first position to lock the image forming unit 120H (developing device 20) in the first position in the housing 101 and the image forming unit 120H. Can be changed with respect to the second posture that allows the device to be detached from the housing 101 along a predetermined attachment / detachment direction.

  Referring to FIGS. 3, 5, and 7, lock lever 50 includes arm portion 501, lever pressed portion 502 (pressed portion), abutting portion 503, guide groove 504, and fulcrum portion 505. And a hook 506.

  The arm portion 501 is a main body portion of the lock lever 50, and as shown in FIG. 7, is arranged so as to extend obliquely from the front and the upper side to the rear and the lower side. The lever pressed portion 502 is a flat portion provided at the upper end portion of the arm portion 501. The lever pressed portion 502 is pressed by the operator when the image forming unit 120H is detached from the housing 101.

  The contact portion 503 is disposed at a substantially central portion in the front-rear direction of the lock lever 50, and protrudes downward when viewed in a cross section orthogonal to the left-right direction (axial direction of the fulcrum portion 505) as shown in FIG. It has an arc shape. When the image forming unit 120H is mounted in the housing 101, the contact portion 503 is disposed to face the guide surface 154 of the main unit 150 as shown in FIGS. The contact is possible.

  The contact part 503 (FIG. 7) includes a first contact part 503A, a second contact part 503B, and a third contact part 503C. The first contact portion 503A, the second contact portion 503B, and the third contact portion 503C are connected by an arc of the contact portion 503.

  The first abutting portion 503A is disposed at a first distance from the fulcrum portion 505, and the hook 506 of the lock lever 50 in the first posture described later of the image forming unit 120H is engaged with the engaged portion 153 (FIG. 7) is engaged with the guide surface 154 in a state where the image forming unit 120H is locked at the first position. Further, the second contact portion 503B is disposed at a second distance larger than the first distance with respect to the fulcrum portion 505 on the lever pressed portion 502 side than the first contact portion 503A. . The second contact portion 503B can be contacted with the guide surface 154, and is disposed apart from the guide surface 154 in a state where the image forming unit 120H is locked at the first position. The third contact portion 503C is disposed at a third distance larger than the second distance with respect to the fulcrum portion 505 on the lever pressed portion 502 side than the second contact portion 503B. The third abutting portion 503C can be brought into contact with the guide surface 154, and is disposed away from the guide surface 154 in a state where the image forming unit 120H is locked at the first position.

  The guide groove 504 is a groove portion opened to the rear of the contact portion 503. The guide groove 504 is opened so as to have an arc shape centered on the fulcrum portion 505. A lever side locking portion 50S is provided on the inner side (fulcrum portion 505 side) of the guide groove 504. The lever side latching portion 50 </ b> S has a hook shape protruding from the lock lever 50. One end of a lever biasing spring 52 described later is locked to the lever side locking portion 50S.

  The fulcrum part 505 is disposed on the rear end side of the lock lever 50. The fulcrum part 505 is rotatably supported on the housing left wall 200 </ b> L of the developing housing 200. Therefore, the lock lever 50 is connected to the housing left wall 200 </ b> L via the fulcrum part 505. The fulcrum part 505 serves as a fulcrum when the lock lever 50 swings. In addition, the above-mentioned contact part 503 is arrange | positioned between the fulcrum part 505 and the lever pressed part 502 (FIG. 7).

  The hook 506 is disposed on the opposite side of the lever pressed portion 502 with respect to the fulcrum portion 505. The hook 506 can be engaged with the engaged portion 153 (FIG. 7) of the main unit 150. As shown in FIG. 7, the hook 506 extends downward from the fulcrum portion 505 and has a tip portion bent forward (a rear end side in the mounting direction of the image forming unit 120H). Note that the hook 506 is rotatable around the fulcrum portion 505 as described in detail later.

  Further, the developing device 20 includes a guide screw 51 and a lever urging spring 52 (second urging member) (FIG. 7). The guide screw 51 is a screw that is inserted into the guide groove 504 and fastened to the housing left wall 200L. The guide screw 51 has a function of guiding the swing of the lock lever 50 along the guide groove 504.

  The lever biasing spring 52 is a spring member that expands and contracts between the housing left wall 200 </ b> L of the developing housing 200 and the lock lever 50. The housing left wall 200L described above includes a housing side locking portion 200L2. As shown in FIG. 7, one end of the lever urging spring 52 is engaged with the lever side engaging portion 50S of the lock lever 50, and the other end of the lever urging spring 52 is engaged with the housing side engaging portion 200L2. Yes. As a result, the lever urging spring 52 moves the lock lever 50 to the fulcrum portion 505 so that the hook 506 engages with the engaged portion 153 (FIG. 7) (the lock lever 50 assumes the first posture described later). Energize around.

  Next, attachment / detachment of the image forming unit 120H with respect to the housing 101 will be described. As described above, the image forming unit 120H includes the developing device 20 and the toner container 30. The toner container 30 is detachable from the developing device 20. Further, the image forming unit 120H can be mounted on the housing 101 only by the developing device 20 without including the toner container 30. Here, a state in which the image forming unit 120H including the toner container 30 is attached to and detached from the housing 101 will be described.

  As shown in FIG. 1, when the front cover 106 of the housing 101 and the front end portion 102 </ b> B of the upper wall 102 are opened, the image forming unit 120 </ b> H is mounted in the main body internal space 107 of the housing 101. At this time, the image forming unit 120H is inserted into the main body internal space 107 along the direction of the arrow DA in FIGS. The main unit 150 (FIG. 3) guides the lower part of the image forming unit 120H. When the image forming unit 120H is inserted, the hook 506 of the lock lever 50 advances backward while sliding on the guide surface 154. Eventually, the inclined surface 506S (FIG. 7) of the hook 506 rubs against the inclined surface 153S of the engaged portion 153. At this time, in FIG. 7, the hook 506 rotates slightly clockwise around the fulcrum 505, so that the tip of the hook 506 enters below the engaged portion 153. As a result, the hook 506 is engaged with the engaged portion 153, and the image forming unit 120H is locked at the first position shown in FIG. The posture of the lock lever 50 in FIG. 7 is defined as the first posture. At this time, as shown in FIG. 10, the housing pressed portion 200K of the developing housing 200 is pressed backward by the biasing protrusion 151 of the positioning mechanism 150S. That is, the positioning mechanism 150S urges the image forming unit 120H in a direction in which the developing roller 210 approaches the photosensitive drum 121. When the image forming unit 120H is positioned in the first position in FIGS. 7 and 10 in the housing 101, the contact roller 211 (FIG. 3) contacts the peripheral surface of the photosensitive drum 121. The developing roller 210 is disposed at a predetermined interval with respect to the photosensitive drum 121. As a result, toner is stably supplied from the developing roller 210 to the photosensitive drum 121, and a toner image is formed on the photosensitive drum 121.

  When the image forming unit 120H is removed from the housing 101, as shown in FIG. 1, when the front cover 106 of the housing 101 and the front end portion 102B of the upper wall 102 are opened, the lever pressed of the lock lever 50 is pressed. The part 502 is exposed outside the printer 100. The operator first presses the lever pressed portion 502 downward (arrow DR1 in FIG. 7). At this time, in the present embodiment, the first contact portion 503A of the contact portion 503 is already in contact with the guide surface 154 (FIG. 7). In this case, since the load for the operator to press the lever pressed portion 502 is generated from the beginning, the operator can press the lever pressed portion 502 while feeling this load.

  19 and 20 are cross-sectional views of an image forming unit and a guide unit in another image forming apparatus compared with the image forming apparatus according to the present embodiment. The other image forming apparatus includes an image forming unit 120HM and a main unit 150M provided in a housing (not shown). The image forming unit 120HM includes a developing device 20M and a toner container 30M. A lock lever 50M is swingably supported by a housing (not shown) of the developing device 20M. In FIGS. 19 and 20, members having structures and functions similar to those in FIG. 7 are denoted by the same reference numerals as in FIG.

  As shown in FIG. 19, when the image forming unit 120HM is locked at a predetermined position, the contact portion 503 of the lock lever 50M is disposed above the guide surface 154 with a gap. In this case, in order to remove the image forming unit 120HM, when the operator presses the lever pressed portion 502 (arrow DR1 in FIG. 19), the operator moves the lever until the contact portion 503 contacts the guide surface 154. Only a small load that pulls the biasing spring 52 is felt. Therefore, when the contact portion 503 comes into contact with the guide surface 154 as shown in FIG. 20, the operator easily misidentifies that the pressing operation of the lock lever 50 is completed as the load increases. In this case, the unlocking of the image forming unit 120HM and the upward movement as indicated by the arrow DR2 in FIG. 20 have not yet been performed. Therefore, if an operator tries to pull out the image forming unit 120HM forcibly, the peripheral parts are damaged. Will be caused.

  On the other hand, in the present embodiment, since the first contact portion 503A of the contact portion 503 is in contact with the guide surface 154 as described above (FIG. 7), the operator applies a predetermined load from the initial stage of the pressing operation. The lever pressed portion 502 of the lock lever 50 can be continuously pressed while feeling. This prevents the operator from releasing his hand from the lock lever 50 during the pressing operation.

  When the lever pressed portion 502 is pressed from the state shown in FIGS. 7 and 10 (arrow DR1 in FIG. 7), the lock lever 50 rotates around the fulcrum portion 505 and the hook 506 and the engaged portion 153 are moved. The engagement is released. At this time, the first contact portion 503A of the contact portion 503 serves as a fulcrum, the fulcrum portion 505 serves as a load point, and the image forming unit 120H is pushed upward against the urging force of the unit urging spring 152 (FIG. 10). Then, the positioning of the image forming unit 120H by the positioning mechanism 150S is released. More specifically, as the image forming unit 120H moves upward, the housing pressed portion 200K (FIG. 10) gets over the tip of the biasing protrusion 151 while compressing the unit biasing spring 152 (FIG. 11). As a result, the positioning of the image forming unit 120H by the positioning mechanism 150S is released. In this embodiment, as described above, the first contact portion 503A of the contact portion 503 serves as a fulcrum, and the positioning of the image forming unit 120H is released by the push-up operation of the image forming unit 120H by the lock lever 50. A distance (first distance) between the first contact portion 503A and the fulcrum portion 505 is set in advance.

  When the lever pressed portion 502 is further pressed by the operator after the positioning by the positioning mechanism 150S is released, the contact point of the contact portion 503 with respect to the guide surface 154 gradually moves backward, and eventually the second contact. The portion 503B contacts the guide surface 154 (FIG. 8). Then, while the second contact portion 503B serves as a fulcrum and the fulcrum 505 serves as a weighting point, the image forming unit 120H receives the urging force of the unit urging spring 152 and moves upward (arrow DR2 in FIG. 8). The second position above the position 1 is reached (FIG. 9). As a result, the third contact portion 503C of the contact portion 503 contacts the guide surface 154. In the present embodiment, the second contact portion 503B serves as a fulcrum, and the image forming unit 120H is pushed upward by the push-up operation of the image forming unit 120H by the lock lever 50. A distance (second distance) between 503B and the fulcrum portion 505 is set in advance.

  As shown in FIG. 11, when the housing pressed portion 200K rides over the urging protrusion 151, the urging protrusion 151 receives the urging force of the unit urging spring 152 to promote the image forming unit 120H. Therefore, compared with the case where the image forming unit 120H is pushed up (the lock lever 50 is rotated) while compressing the unit biasing spring 152 from the state shown in FIG. For this reason, in this embodiment, the first contact part 503A, the second contact part 503B, and the third contact part 503C of the contact part 503 are set so that the distance to the fulcrum part 505 increases. . In other words, the lever ratio with the fulcrum portion 505 as the weight point decreases in the order of the first contact portion 503A, the second contact portion 503B, and the third contact portion 503C of the contact portion 503. Therefore, compared to the case where the first contact portion 503A is in contact with the guide surface 154, the case where the periphery of the second contact portion 503B and the third contact portion 503C is in contact with the guide surface 154 is greater. The amount by which the pressing portion 502 is pushed down can be greatly reduced to the amount by which the image forming unit 120H is pushed up. As described above, in this embodiment, the movement of the housing pressed portion 200K of the image forming unit 120H can cancel the positioning by the positioning mechanism 150S and promote the movement of the image forming unit 120H.

  In addition, after the image forming unit 120H is pushed up in the direction indicated by the arrow DR2 from the state shown in FIG. 8, the hook 506 is guided above the engaged portion 153 by the weight of the image forming unit 120H (the above-described horizontal plane). , The image forming unit 120H is held in the second position. For this reason, even when the operator releases his / her hand from the lock lever 50, the hook 506 is prevented from being re-engaged with the engaged portion 153. For this reason, the operator can remove the image forming unit 120H easily and reliably.

  On the other hand, as shown in FIG. 9, when the operator presses the lever pressed portion 502 of the lock lever 50, the following problems occur when the first contact portion 503A is already in contact with the guide surface 154. Was found to occur. FIG. 21 is a cross-sectional view of an image forming unit and a guide unit in another image forming apparatus compared with the image forming apparatus according to the present embodiment. The other image forming apparatus includes an image forming unit 120HN and a main unit 150N provided in a housing (not shown). The image forming unit 120HN includes a developing device 20N and a toner container 30N. A lock lever 50N is swingably supported by a housing (not shown) of the developing device 20N. In FIG. 21, members having structures and functions similar to those in FIG. 7 are denoted by the same reference numerals as in FIG. 7.

  In the lock lever 50N shown in FIG. 21, the relative positional relationship between the contact portion 503 and the hook 506 is fixed. Therefore, when the image forming unit 120HN is mounted in the housing and is pressed down in the direction of arrow DW in FIG. 21 while compressing the unit biasing spring 152 (FIG. 11) of the positioning mechanism 150S, the contact portion 503 is guided. While abutting on the surface 154, the hook tip 506S of the hook 506 may abut on the inclined surface 153S of the engaged portion 153. As described above, when the lock lever 50N simultaneously contacts the main unit 150N at two locations, it becomes difficult to engage the hook 506 and the engaged portion 153, and the mounting of the image forming unit 120HN is not realized stably. Occurs.

  In order to solve such a problem, in this embodiment, the structure of the lock lever 50 is provided with a further feature. 12 and 13 are exploded perspective views of the lock lever 50 according to the present embodiment. 14 and 15 are perspective views of the lock lever 50. FIG. 16 and 17 are exploded perspective views of the image forming unit 120H and the lock lever 50. FIG. FIG. 18 is a cross-sectional view of the image forming unit 120H and the main body unit 150, and shows a state where the hook 506 of the lock lever 50 is rotated.

  12 to 17, the lock lever 50 includes a lever main body 50A and a hook portion 50B. That is, in this embodiment, the lock lever 50 is composed of two members. As shown in FIG. 12, the lever main body 50 </ b> A includes the aforementioned arm portion 501, lever pressed portion 502, contact portion 503, and guide groove 504. On the other hand, the hook part 50 </ b> B includes the lever side locking part 50 </ b> S, the fulcrum part 505, and the hook 506.

  When a cylindrical insertion flange 502A formed at one end of the lever main body 50A is inserted into the fulcrum part 505 of the hook part 50B, the hook part 50B is rotatable with respect to the lever main body 50A. That is, the hook 506 can be rotated around the fulcrum portion 505. At this time, an arcuate guide rib 505S disposed around the fulcrum 505 slides with the insertion flange 502A to guide the rotation of the hook 506.

  Further, referring to FIG. 13, the lever main body 50 </ b> A includes a main body contact portion 50 </ b> V. The main body contact portion 50V is a wall portion disposed between the guide groove 504 and the insertion flange 502A. On the other hand, the hook part 50B includes a hook side contact part 50T. The hook-side contact portion 50T is a projecting piece projecting radially outward from the fulcrum portion 505, and has a substantially trapezoidal shape as shown in FIG. Further, in the rotation direction around the fulcrum part 505, the hook side contact part 50T is arranged at a predetermined interval with respect to the lever side locking part 50S. The hook side contact part 50T and the main body contact part 50V in the present embodiment constitute an interlocking part of the present invention. The interlocking portion moves the hook 506 to the lever pressed portion when the lever pressed portion 502 is rotated around the fulcrum portion 505 in the direction indicated by the arrow DB in FIG. 15 (second rotation direction opposite to the first rotation direction). A function of rotating integrally with 502 is provided.

  As shown in FIGS. 14 to 17, the hook portion 50B is attached to the lever main body 50A, and the guide screw 51 inserted into the guide groove 504 is fastened to a stud 200L3 protruding from the housing left wall 200L. Thus, the lock lever 50 is swingably attached to the housing left wall 200L. Further, the hook portion 50B is rotatable with respect to the lever main body 50A.

  Referring to FIG. 15, when lock lever 50 is mounted on housing left wall 200L, lever urging spring 52 provided between lever side locking portion 50S and housing side locking portion 200L2 (FIG. 7). As a result, the hook portion 50B is urged in the direction of the arrow DA in FIG. At this time, the lever biasing spring 52 moves the hook 506 around the fulcrum 505 in the first rotation direction (opposite to the arrow DK in FIG. 15) so that the hook 506 engages with the engaged portion 153 (FIG. 7). Direction). The lever main body 50A is also urged in the first rotational direction by the urging force of the lever urging spring 52 when the abutment surface 50T1 of the hook side abutment portion 50T abuts on the main body abutment portion 50V.

  In FIG. 15, when the lever pressed portion 502 of the lever main body 50A is pressed in the arrow DB direction by the operator, the main body contact portion 50V moves the contact surface 50T1 of the hook side contact portion 50T in the arrow DC direction. In order to press, the hook 506 rotates in the arrow DK direction. That is, when the unlocking operation of the lock lever 50 is performed by the operator, the lever main body 50A and the hook portion 50B can rotate integrally.

  Further, in FIG. 15, the hook portion 50B can independently rotate in the arrow DK direction with respect to the lever main body 50A in a state where no operating force is applied to the lever main body 50A. At this time, the hook part 50 </ b> B rotates around the fulcrum part 505 against the urging force of the lever urging spring 52.

  Also in such a configuration, as shown in FIG. 18, the image forming unit 120H is mounted in the casing 101, and the unit biasing spring 152 (FIG. 11) of the positioning mechanism 150S is compressed and pushed down in the arrow DW direction. In this case, the contact portion 503 contacts the guide surface 154, and the hook tip portion 506S of the hook 506 may contact the inclined surface 153S of the engaged portion 153 (see FIG. 21). Even in such a case, in the present embodiment, since the hook portion 50B is rotatable with respect to the lever main body 50A, the hook 506 is temporarily engaged as shown by the arrow DR in FIG. It can rotate in a direction away from the portion 153. Therefore, the image forming unit 120H is pushed downward while the contact portion 503 is in contact with the guide surface 154, and the temporarily rotated hook 506 is returned to the original posture by the biasing force of the lever biasing spring 52. can do. At this time, the hook 506 is engaged with the engaged portion 153, and the image forming unit 120H is fixed at the first position in the housing 101.

  As described above, in this embodiment, when the image forming unit 120H is mounted at the first position, the hook 506 and the contact portion 503 are simultaneously in contact with the engaged portion 153 and the guide surface 154, respectively. Even so, the image forming unit 120H can be smoothly mounted by the rotation of the hook 506.

  In this embodiment, the lever biasing spring 52 biases the hook 506 around the fulcrum portion 505 in the first rotation direction so that the hook 506 engages with the engaged portion 153. For this reason, the hook 506 can be maintained in a posture to be engaged with the engaged portion 153 by the biasing force of the lever biasing spring 52. For this reason, the engagement between the hook 506 and the engaged portion 153 is prevented from being erroneously released.

  In the present embodiment, an interlocking portion constituted by the hook side contact portion 50T and the main body contact portion 50V is disposed. For this reason, even if the hook 506 can be rotated around the fulcrum portion 505, the engagement between the hook 506 and the engaged portion 153 can be smoothly released in accordance with the pressed operation of the lock lever 50. it can.

  Further, according to the present embodiment, the lock lever 50 can be changed in posture between the first posture and the second posture by being swung. When the hook 506 of the lock lever 50 is engaged with the engaged portion 153 of the main body unit 150, the image forming unit 120H is locked at the first position. Further, when the lever pressed portion 502 of the lock lever 50 is pressed, the lock of the image forming unit 120H is released and the image forming unit 120H is detached from the housing 101 along a predetermined attaching / detaching direction. Is acceptable. As a result, it is possible to easily and reliably execute positioning and detachment of the image forming unit 120H. Further, when the operator presses the lock lever 50, the first contact portion 503A is in contact with the guide surface 154, so that a predetermined pressing load is generated on the lock lever 50. For this reason, compared with the case where there is play in the lock lever 50, it is possible to prevent the operator from making a work mistake. Furthermore, since the lever ratio of the first contact portion 503A is set to be relatively large in the contact portion 503, positioning by the positioning mechanism 150S is easy against the biasing force of the unit biasing spring 152. Can be released. Further, since the lever ratio of the second contact portion 503B is set to be smaller than that of the first contact portion 503A, when the image forming unit 120H is pushed up while receiving the biasing force of the unit biasing spring 152, the operator It is possible to reduce the pressing force required for the operation.

  In the present embodiment, the first contact portion 503A to the third contact portion 503C are connected by an arc of the contact portion 503. Therefore, the operator can release the lock of the image forming unit 120H and move from the first position to the second position by continuously pressing the lock lever 50.

  The printer 100 including the image forming unit 120H according to the embodiment of the present invention has been described above. According to such a configuration, it is possible to provide the printer 100 that can easily and reliably execute positioning and detachment of the image forming unit 120H. In addition, even when the toner container 30 is mounted on the developing device 20, the developing device 20 can be easily and reliably positioned and attached. In addition, this invention is not limited to this, For example, the following modified embodiment is employable.

  (1) In the above-described embodiment, the image forming unit 120H has been described as including the developing device 20 and the toner container 30, but the present invention is not limited to this. The image forming unit 120H may include only the developing device 20, and the image forming unit 120H may include the photosensitive drum 121.

  (2) In the embodiment described above, the contact roller 211 is provided as the spacing member, but the present invention is not limited to this. A thing other than a roller shape may be provided as an interval holding member.

100 Printer (image forming device)
101 Case (device main body)
107 Internal space 120 Image forming unit 120H Image forming unit 121 Photosensitive drum (image carrier)
150 Main unit (guide section)
150S positioning mechanism 151 urging protrusion (unit contact portion)
152 Unit biasing spring (first biasing member)
153 engaged portion 154 guide surface 20 developing device 200 developing housing 200H toner supply port 200K housing pressed portion 200L2 housing side latching portion 210 developing roller 211 abutting roller (spacing holding member)
30 Toner container (developer container)
50 Lock lever (lever member)
501 Arm part 502 Lever pressed part (pressed part)
503 Contact portion 504 Guide groove 505 Support point portion 506 Hook 50A Lever body 50B Hook portion 50S Lever side locking portion 50T Hook side contact portion (interlocking portion)
50V body contact part (interlocking part)
51 Guide screw 52 Lever biasing spring (second biasing member)

Claims (9)

The device body;
An image forming unit that can be attached to and detached from the apparatus main body along a predetermined attaching and detaching direction;
A guide portion disposed in the apparatus main body for guiding attachment / detachment of the image forming unit;
A first position in the apparatus main body, comprising a first urging member disposed on the guide portion and a unit abutting portion that abuts on the image forming unit by receiving the urging force of the first urging member. A positioning mechanism for urging the image forming unit mounted on the image forming unit to position the image forming unit;
The image forming unit is provided so as to be swingable, and in the apparatus main body, the image forming unit is locked in the first position, the image forming unit is unlocked, and the image forming unit is unlocked. A lever member capable of changing the posture between a second posture allowing the forming unit to be detached from the apparatus main body along the attaching / detaching direction;
Have
The guide portion is
A guide surface for guiding the image forming unit;
An engaged portion disposed on the front side in the mounting direction of the image forming unit with respect to the guide surface;
With
The lever member is
A fulcrum portion serving as a fulcrum in the swing;
A pressed portion to be pressed in order to detach the image forming unit from the apparatus main body;
A hook disposed on the opposite side of the pressed portion with respect to the fulcrum portion, rotatable around the fulcrum portion, and engageable with the engaged portion of the guide portion;
An abutting portion disposed between the fulcrum portion and the pressed portion and capable of abutting on the guide surface of the guide portion;
With
The contact portion is disposed at a first distance with respect to the fulcrum portion, the hook of the lever member in the first posture is engaged with the engaged portion, and the image forming unit is A first contact portion that contacts the guide surface in a locked state at the first position;
When the pressed portion of the lever member is pressed in a state where the image forming unit is locked at the first position, the lever member rotates around the fulcrum portion and the hook and the engaged portion The first abutting portion serves as a fulcrum and the fulcrum serves as a load point, and the image forming unit is pushed upward against the urging force of the first urging member, The image forming apparatus according to claim 1, wherein the first distance of the first contact portion is set so that positioning of the image forming unit by the positioning mechanism is released.   The image according to claim 1, further comprising a second urging member that urges the hook around the fulcrum in a first rotation direction so that the hook engages with the engaged portion. Forming equipment.   The lever member rotates the hook integrally with the pressed portion when the pressed portion is rotated around the fulcrum in a second rotation direction opposite to the first rotation direction. The image forming apparatus according to claim 2, further comprising an interlocking unit. The abutting portion is further disposed at a second distance larger than the first distance with respect to the fulcrum portion on the pressed portion side with respect to the first abutting portion, and is disposed on the guide surface. A second abutting portion that is capable of abutting and is disposed apart from the guide surface in a state where the image forming unit is locked at the first position;
After the positioning by the positioning mechanism is released, when the pressed part is further pressed, the second contact part comes into contact with the guide surface, the second contact part becomes a fulcrum, and the fulcrum part is added. The image forming unit receives the biasing force of the first biasing member and reaches a second position above the first position, and the image forming unit moves along the attachment / detachment direction. 4. The image forming apparatus according to claim 1, wherein the second distance of the second contact portion is set so as to be detachable from the main body. 5. When viewed in a cross section orthogonal to the axial direction of the fulcrum portion, the contact portion has an arc shape,
The image forming apparatus according to claim 4, wherein the first contact portion and the second contact portion are connected by the arc. The unit contact portion of the positioning mechanism includes a tapered tip portion along a mounting direction of the image forming unit with respect to the apparatus main body,
The image forming unit includes a unit pressed portion that is pressed by the unit contact portion,
When the first contact portion serves as a fulcrum and the fulcrum serves as a load point, and the image forming unit is pushed upward against the urging force of the first urging member, the unit pressed portion is Positioning the image forming unit by the positioning mechanism is released by overcoming the tip of the unit abutting portion while compressing one urging member, and the unit abutting portion is moved to the first urging member. The unit pressed portion of the image forming unit arranged at the first position is arranged to face the unit contact portion so as to promote the pushing-up of the image forming unit by receiving the urging force of The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The image forming apparatus further includes an image carrier that is rotatably disposed on the apparatus main body and has an electrostatic latent image formed on a peripheral surface thereof.
The image forming unit has a developing device including a developing roller for supplying a developer to the image carrier,
The positioning mechanism urges the image forming unit toward a direction in which the developing roller approaches the image carrier,
2. The apparatus according to claim 1, wherein when the image forming unit is positioned at the first position in the apparatus main body, the developing roller is arranged at a predetermined interval with respect to the image carrier. The image forming apparatus according to any one of 6.   The image forming apparatus according to claim 7, wherein the developing device includes an interval holding member that is disposed at both ends in the axial direction of the developing roller and contacts the circumferential surface of the image carrier.   The image forming unit further includes a developer container that can be attached to and detached from the developing device and can be attached to and detached from the developing device integrally with the developing device. Item 9. The image forming apparatus according to Item 7 or 8.

Images