Image forming device

Abstract

The present invention provides an image forming device. The image forming device has a drum unit, a developing device, a developing holder and a sliding component. The drum unit has a photosensitive drum. The developing device has a developing roller, which is arranged in a manner that its outer peripheral surface faces the outer peripheral surface of the photosensitive drum. The developing holder can detach the developing device and swing the developing roller in a manner that makes the developing roller approach and leave the photosensitive drum. The sliding component slides in the axial direction of the developing roller. The developing holder and the sliding component slide from a first position to a second position in linkage so as to swing the developing roller in a manner that makes the developing roller approach the photosensitive drum, and the developing holder and the sliding component slide from the second position to the first position in linkage so as to swing the developing roller away from the photosensitive drum. Accordingly, the developing device can be easily and accurately positioned by a simple structure.

Description

Technical Field

[0001] The present invention relates to an image forming device. Background Art

[0002] An image forming apparatus of an electronic photographic method has a photosensitive drum and a developing device. When the photosensitive drum reaches the end of its service life, the photosensitive drum needs to be replaced. The developing device requires regular maintenance. Therefore, a structure is generally adopted in which the drum unit including the photosensitive drum and the developing device can be individually disassembled and assembled relative to the main body of the image forming apparatus. For example, there is the following situation: the image forming apparatus has a unit support frame and a developing holding frame, wherein the unit support frame supports the drum unit and the developing device in a manner that the drum unit and the developing device can be individually disassembled and assembled, the developing holding frame is arranged on the unit support frame, and the developing device is held in a manner that the developing roller can swing toward or away from the photosensitive drum, and the developing holding frame has a driving gear and a pair of swinging shaft portions, wherein the driving gear transmits power to the developing device, and the pair of swinging shaft portions have a rotation axis extending parallel to the axial direction of the developing roller, and are supported on the unit support frame in a rotatable manner.

[0003] However, since the above-mentioned image forming apparatus includes a cam for swinging the developing device and a gear for linking the opening and closing of the cover with the operation of the cam, the number of parts increases and the cost rises. Summary of the invention

[0004] In view of the above, an object of the present invention is to provide an image forming apparatus capable of easily and accurately positioning a developing device with a simple structure.

[0005] The image forming device involved in the present invention comprises a drum unit, a developing device, a developing holder and a sliding member. The drum unit comprises a photosensitive drum. The developing device comprises a developing roller, which is arranged in such a manner that its outer peripheral surface faces the outer peripheral surface of the photosensitive drum. The developing holder is capable of detaching the developing device and swinging in such a manner that the developing roller approaches and moves away from the photosensitive drum. The sliding member slides in the axial direction of the developing roller. The developing holder is linked to the sliding of the sliding member from a first position to a second position so as to swing in such a manner that the developing roller approaches the photosensitive drum, and the developing holder is linked to the sliding of the sliding member from the second position to the first position so as to swing in such a manner that the developing roller moves away from the photosensitive drum. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a perspective view showing the appearance of an image forming apparatus according to an embodiment of the present invention.

[0007] Figure 2It is a front view schematically showing the internal structure of the image forming apparatus according to one embodiment of the present invention.

[0008] Figure 3 It is a perspective view of an imaging device and an inner cover according to an embodiment of the present invention.

[0009] Figure 4 It is a perspective view of an imaging device and an inner cover according to an embodiment of the present invention.

[0010] Figure 5 It is a perspective view of a drum unit according to an embodiment of the present invention.

[0011] Figure 6 It is a perspective view of a developing device according to an embodiment of the present invention.

[0012] Figure 7 It is a front view schematically showing the structure of an imaging device according to an embodiment of the present invention.

[0013] Figure 8 It is a front view schematically showing the structure of an imaging device according to an embodiment of the present invention.

[0014] Fig. 9 It is a perspective view showing a state where a developer holder is attached to a unit support frame according to an embodiment of the present invention.

[0015] Fig.10 It is a perspective view of a unit support frame according to one embodiment of the present invention.

[0016] Fig.11 It is a perspective view of a developer holder and a lower guide rail according to an embodiment of the present invention.

[0017] Fig.12 It is a perspective view of a developer holder, an upper guide rail, and a lower guide rail according to an embodiment of the present invention.

[0018] Fig.13 It is a cross-sectional view of a lower guide rail and a developing device according to an embodiment of the present invention.

[0019] Fig.14 It is a cross-sectional view of a lower guide rail and a developing device according to an embodiment of the present invention.

[0020] Fig.15 It is a cross-sectional view of a lower guide rail and a developing device according to an embodiment of the present invention.

[0021] Fig.16 It is a side view of a link member according to an embodiment of the present invention.

[0022] Fig.17It is a side view of a link member according to an embodiment of the present invention.

[0023] Fig.18 It is a side view of a link member according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] Hereinafter, an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.

[0025] First, the overall structure of the image forming apparatus 100 will be described. Figure 1 It is a perspective view showing the appearance of the image forming apparatus 100 . Figure 2 FIG. 1 is a front view schematically showing the internal structure of the image forming apparatus 100. Figure 2 The front side of the paper in the figure is the front side (front side) of the image forming apparatus 100, and the left and right directions are described based on the direction of viewing the image forming apparatus 100 from the front. In each figure, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and back, respectively.

[0026] The image forming apparatus 100 includes a printer 1, a scanner 110, and a document conveying device 120. The scanner 110 is provided above the printer 1, and the document conveying device 120 is provided above the scanner 110. The document conveying device 120 conveys a document along a conveying path passing through a reading position of the scanner 110. The scanner 110 is a flatbed image scanner that reads a document and generates image data. The printer 1 forms an image based on the image data on a sheet S.

[0027] The printer 1 and the scanner 110 are integrated by a housing 3. A paper feed cassette 4 and a paper feed roller 5 are provided at the lower part of the interior of the housing 3, wherein the paper feed cassette 4 accommodates the sheet S, and the paper feed roller 5 feeds the sheet S to the right from the paper feed cassette 4. An image forming device 6 is provided above the paper feed cassette 4, and the image forming device 6 forms a toner image by an electronic photographic method, and a fixing device 7 is provided at the upper right of the image forming device 6, and the fixing device 7 is used to fix the toner image on the sheet S. A paper discharge roller 8 and a paper discharge tray 9 are provided above the fixing device 7, wherein the paper discharge roller 8 is used to discharge the sheet S with the toner image fixed thereon, and the paper discharge tray 9 is used to load the discharged sheet S.

[0028] A conveying path 10 is provided inside the housing 3, which extends from the paper supply roller 5 through the image forming device 6 and the fixing device 7 to the paper discharge roller 8. The conveying path 10 is mainly formed by plate-like members facing each other with a gap for the sheet S to pass through, and conveying rollers 17 that clamp the sheet S for conveying are provided at multiple positions in the conveying direction Y. A resist roller 18 is provided at a position upstream of the image forming device 6 in the conveying direction Y. A reversing conveying path 10R is provided on the right side of the fixing device 7, and the reversing conveying path 10R branches from the conveying path 10 at a position downstream of the fixing device 7 in the conveying direction Y, and merges with the conveying path 10 at a position upstream of the resist roller 18 in the conveying direction Y.

[0029] The imaging device 6 includes a photosensitive drum 11, a charging device 12, an exposure device 13, a developing device 14, an intermediate transfer unit 15 and a cleaning device 16, wherein the potential of the photosensitive drum 11 changes by being irradiated with light, the charging device 12 charges the photosensitive drum 11, the exposure device 13 emits a laser corresponding to the image data, the developing device 14 supplies colorant to the photosensitive drum 11, the intermediate transfer unit 15 transfers the colorant image from the photosensitive drum 11 to the sheet S, and the cleaning device 16 removes the colorant remaining on the photosensitive drum 11. The intermediate transfer unit 15 has an intermediate transfer belt 15B, a primary transfer roller 151 and a secondary transfer roller 152, wherein the intermediate transfer belt 15B is annular and is wound around a driving roller 15D and a driven roller 15N; the primary transfer roller 151 faces the inner peripheral surface of the intermediate transfer belt 15B at a position corresponding to the photosensitive drum 11 and generates a primary transfer bias; the secondary transfer roller 152 faces the outer peripheral surface of the intermediate transfer belt 15B at a position corresponding to the driving roller 15D and generates a secondary transfer bias. A toner container 20 is connected to the developing device 14, and the toner container 20 supplies toner to the developing device 14.

[0030] The image forming device 6 has four sets of photosensitive drums 11, charging devices 12, exposure devices 13, developing devices 14, primary transfer rollers 151, cleaning devices 16, and toner containers 20, and forms a color image by superimposing toner images of four colors on an intermediate transfer belt 15B. In addition, the present invention can also be applied to an image forming device that forms a color image using toners of three or less colors or five or more colors.

[0031] The control unit 2 has a computing unit and a storage unit. The computing unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as ROM (Read Only Memory), RAM (Random Access Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). The computing unit performs various processes by reading and executing the control program stored in the storage unit. In addition, the control unit 2 can also be implemented only by an integrated circuit without using software.

[0032] An operation panel 19 is provided on the front side of the scanner 110. The operation panel 19 includes a display screen, a touch screen superimposed on the display surface of the display screen, and a keypad adjacent to the display screen. The control unit 2 displays a screen showing an operation menu, status, etc. of the printer 1 and the scanner 110 on the display screen, and controls each unit of the printer 1 and the scanner 110 according to the operation detected by the touch screen and the keypad.

[0033] The basic image forming operation of the printer 1 is as follows. When a print job for single-sided printing is input to the printer 1 from an external computer or the like, the paper feed roller 5 feeds the sheet S from the paper feed cassette 4 to the conveying path 10, the registration roller 18 stops rotating to correct the skew of the sheet S, and the registration roller 18 feeds the sheet S to the image forming device 6 at a predetermined timing. In the image forming device 6, the charging device 12 charges the photosensitive drum 11 to a predetermined potential, the exposure device 13 writes a latent image on the photosensitive drum 11, the developing device 14 develops the latent image using the toner supplied from the toner container 20, thereby forming a toner image, the primary transfer roller 15A transfers the toner image to the intermediate transfer belt 15B, and the secondary transfer roller 15C transfers the toner image to the sheet S. Next, the fixing device 7 melts the toner image while sandwiching the sheet S and conveying it, thereby fixing the toner image to the sheet S, and the discharge roller 8 discharges the sheet S to the discharge tray 9. The cleaning device 16 removes the toner remaining on the photosensitive drum 11. In the case of double-sided printing, the sheet S having the toner image fixed on the first surface is conveyed to the conveyance path 10 through the reverse conveyance path 10R, so that the toner image is transferred on the second surface.

[0034] Next, the imaging device 6 will be described in detail. Figure 3 It is a perspective view of the imaging device 6 and the inner cover 3C (in a state where the inner cover 3C is closed). Figure 4 It is a perspective view of the imaging device 6 and the inner cover 3C (a state in which the inner cover 3C is opened). Figure 5 It is a perspective view of the drum unit 50 . Figure 6It is a perspective view of the developing device 14 . Figure 7 and Figure 8 It is a front view schematically showing the structure of the imaging device 6 (excluding the exposure device 13).

[0035] [Inner cover]

[0036] An opening 3A and a cover 3B (see FIG. 3B ) for closing the opening 3A are provided above the paper feed cassette 4 on the front surface of the housing 3. Figure 1 ). By opening (or removing) the outer cover 3B, the opening 3A is opened, and the inner cover 3C (an example of a cover) is exposed (refer to Figure 3 , Figure 4 The lower end of the inner cover 3C is connected to the opening 3A by a hinge 3H with the left-right direction as the axial direction. Four sets of detachable drum units 50 and developing devices 14 are provided at the rear of the inner cover 3C.

[0037] [Drum Unit]

[0038] Drum unit 50 (see Figure 5 , Figure 7 ) is a unit formed by integrating the photosensitive drum 11, the charging device 12 and the cleaning device 16. The lower part of the drum unit 50 is formed into a box shape with the front-rear direction as the longitudinal direction, and the charging device 12 is accommodated in the inside. The photosensitive drum 11 is arranged above the charging device 12, and the cleaning device 16 is arranged on the right side of the photosensitive drum 11.

[0039] [Developing device]

[0040] The developing device 14 (see Figure 6 , Figure 7 ) has two screws 33, a developing roller 32, a housing 31 and a scraper 34, wherein the screw 33 rotates around an axis to stir the developer; the developing roller 32 holds the developer above the screw 33; the housing 31 accommodates the screw 33 and the developing roller 32, and has an opening 35 that exposes a portion of the outer circumference of the developing roller 32; the scraper 34 is arranged below the opening 35 to limit the thickness of the developer held by the developing roller 32. The developing roller 32 and the screw 33 are both arranged with the front-rear direction as the axial direction.

[0041] The developer is, for example, a two-component developer containing a magnetic carrier and a non-magnetic toner. Two screws 33 are arranged in parallel to each other in the left and right directions inside the housing 31, and convey the developer in opposite directions. A partition wall 36 is provided between the two screws 33. A gap is provided between the front end of the partition wall 36 and the inner surface of the housing 31, and between the rear end of the partition wall 36 and the inner surface of the housing 31, and the developer circulates around the partition wall 36 through the gap. By stirring the developer with the screw 33, the toner is frictionally charged.

[0042] The developing roller 32 is arranged in parallel above the screw 33 on the right side. The developing roller 32 has a permanent magnet and a developing sleeve (not shown), wherein the developing sleeve is formed of a non-magnetic material covering the periphery of the permanent magnet. A driven gear 32G is provided at the rear end of the developing roller 32. An opening 35 is formed on the right side of the upper part of the housing 31, and the outer peripheral surface of the developing roller 32 exposed from the opening 35 faces the outer peripheral surface of the photosensitive drum 11. The developer forms a layer of magnetic brush on the surface of the developing roller 32. The scraper 34 is arranged so that its top end is separated from the developing roller 32 by a predetermined interval, and the layer thickness of the magnetic brush is adjusted to a predetermined thickness.

[0043] Annular spacing limiting members 32S having a larger diameter than the developing sleeve are provided at both ends of the developing roller 32. The spacing limiting members 32S contact the outer peripheral surface of the photosensitive drum 11, thereby causing the outer peripheral surfaces of the developing sleeve and the photosensitive drum 11 to face each other at a predetermined distance.

[0044] Next, a structure for positioning the developing device 14 will be described. Fig. 9 It is a perspective view showing a state where the developer holding frame 70 is attached to the unit supporting frame 60 . Fig.10 It is a perspective view of the unit support frame 60 . Fig.11 It is a perspective view of the developer holding frame 70 and the lower guide rail 42. Fig.12 It is a perspective view of the developer holding frame 70 , the upper guide rail 41 , and the lower guide rail 42 . Fig.13 4 is a cross-sectional view of the lower guide rail 42 and the developing device 14 (in a state where the inner cover 3C is completely closed). Fig.14 1 is a cross-sectional view of the lower guide rail 42 and the developing device 14 (a state in which the inner cover 3C is at a predetermined position between fully closed and fully opened). Fig.15 4 is a cross-sectional view of the lower guide rail 42 and the developing device 14 (inner cover 3C is fully opened). Figures 13 to 15 A cross section along the axis of the left screw 33 is shown. Figures 16 to 18 It is a side view of the link member 43.

[0045] The image forming device 100 includes a drum unit 50, a developing device 14, a developing holder 70 and a lower guide rail 42 (an example of a sliding component), wherein the drum unit 50 includes a photosensitive drum 11; the developing device 14 includes a developing roller 32, and the developing roller 32 is arranged in a manner that its outer peripheral surface faces the outer peripheral surface of the photosensitive drum 11; the developing holder 70 can disassemble the developing device 14 and swing in a manner that the developing roller 32 approaches and moves away from the photosensitive drum 11; the lower guide rail 42 slides in the axial direction of the developing roller 32, the developing holder 70 slides in conjunction with the lower guide rail 42 from a first position to a second position so as to swing in a manner that the developing roller 32 approaches the photosensitive drum 11, and the developing holder 70 slides in conjunction with the lower guide rail 42 from the second position to the first position so as to swing in a manner that the developing roller 32 moves away from the photosensitive drum 11.

[0046] [Unit support frame]

[0047] Unit support frame 60 (see Fig. 9 , Fig.10 ) is a component that supports the four-group drum unit 50 and the developing device 14. The unit support frame 60 has a substantially rectangular plate-shaped bottom 60B and is fixed to the housing 3. A drum unit support portion 62, a holder support portion 61, and a lower rail support portion 63 are provided on the upper surface of the unit support frame 60.

[0048] The drum unit support portion 62 is a concave portion into which the lower portion of the drum unit 50 is fitted. A developer holder 70 is provided on the left side of the drum unit support portion 62, and the developer holder 70 supports the developer device 14 paired with the drum unit 50. The developer holder 70 is supported by the holder support portion 61. The holder support portion 61 has a first fulcrum 611 and a second fulcrum 612, and the first fulcrum 611 and the second fulcrum 612 support two positions of the developer holder 70 in the front-to-back direction. A wall portion 60W standing upright upward is provided at the rear end portion of the unit support frame 60. The first fulcrum 611 is a cylindrical shaft protruding forward from the wall portion. The second fulcrum 612 is an upright plate-shaped component provided at a position forward of the first fulcrum 611, and has a circular hole penetrating in the front-to-back direction. The center line of the axis of the first fulcrum 611 passes through the center of the hole of the second fulcrum 612. The lower rail support portion 63 is provided on the left side portion of the upper surface of the holder support portion 61 and supports the lower rail 42 slidably in the front-rear direction by contacting left and right side surfaces of the lower rail 42 described later.

[0049] [Developer holder]

[0050] The developer holder 70 (see Fig.11 , Fig.12) has an axial connection portion 71 connected to the rear end of the developing device 14 and a bottom support portion 72 that supports the bottom of the developing device 14. The axial connection portion 71 faces the rear end of the developing device 14 and has a driving gear 71G. The driving gear 71G is driven by a motor through a reduction gear (not shown). The bottom support portion 72 is a roughly rectangular plate-shaped member with the front-to-back direction as the longitudinal direction, and has a wall portion that limits the positional deviation of the developing device 14 in the left-right direction.

[0051] A first fulcrum 721 and a second fulcrum 722 are provided at the right end of the bottom support portion 72. The first fulcrum 721 is a circular hole into which the first fulcrum 611 of the unit support frame 60 is engaged. The second fulcrum 722 is a cylindrical shaft engaged with the second fulcrum 612 of the unit support frame 60. A fulcrum 37 is provided at the lower right portion of the front end portion of the housing 31 of the developing device 14. The fulcrum 37 is, for example, a hole that penetrates in the front-to-back direction. The fulcrum 37 is externally fitted to the second fulcrum 722 of the developing holder 70. The developing holder 70 and the developing device 14 can swing around the first fulcrum 721 and the second fulcrum 722.

[0052] The developing device 14 is installed on the developing frame 70 by being pushed into the developing frame 70 from the front. At this time, the driven gear 32G of the developing roller 32 meshes with the driving gear 71G of the developing frame 70. The developing device 14 is removed from the developing frame 70 by being pulled forward from the developing frame 70.

[0053] [Upper rail, lower rail]

[0054] The upper rail 41 and the lower rail 42 (see Figures 11 to 15 ) is a rod-shaped member whose overall length direction is the front-to-back direction. The upper guide rail 41 is fixed to the left side portion of the lower surface of the developer holder 70. As described above, the lower guide rail 42 is slidably provided on the upper surface of the unit support frame 60. The upper guide rail 41 and the lower guide rail 42 face each other in the up-down direction.

[0055] The upper rail 41 has a main body 41M with a rectangular cross section. On the lower surface of the main body 41M, a first convex portion 41T protruding downward is provided at a position slightly behind the center portion in the front-to-back direction of the developer holder 70. The first convex portion 41T has left and right side surfaces, a front surface, a rear surface, and a lower surface, and the front surface is inclined in such a manner that the upper end portion is located in front of the lower end portion. A concave portion 41U elongated in the front-to-back direction is provided in front of the first convex portion 41T so as to be adjacent thereto. The width of the concave portion 41U in the left-to-right direction is narrower than the width of the first convex portion 41T.

[0056] A guide member 41G is provided on the lower surface of the upper guide rail 41 at a position forward of the recessed portion 41U. The guide member 41G includes a groove member 41GU and a rod-shaped member 41GB, the rod-shaped member 41GB having a length direction in the left-right direction. The groove member 41GU includes a top plate portion and left and right side walls, and the top plate portion is fixed to the lower surface of the upper guide rail 41. The rod-shaped member 41GB is provided inside the groove member 41GU, and the left and right ends of the rod-shaped member 41GB are supported by the left and right side walls of the groove member 41GU.

[0057] The lower rail 42 has a main body 42M with a rectangular cross section. The front end of the main body 42M is bent downward and has a boss 42B protruding to the right. A second convex portion 42T protruding upward is provided on the upper surface of the lower rail 42. The second convex portion 42T has left and right side surfaces, a front surface, a rear surface, and an upper surface, and the rear surface is inclined in such a way that the upper end is located forward of the lower end. The width of the second convex portion 42T in the left-right direction is slightly narrower than the width of the recess 41U of the upper rail 41, and the second convex portion 42T can enter the recess 41U.

[0058] The lower guide rail 42 is provided with a notch 42K into which the rod-shaped member 41GB of the guide member 41G of the upper guide rail 41 can be inserted. The notch 42K includes an axial portion 42KA extending in the front-rear direction (the axial direction of the developing roller 32) and an inclined portion 42KS inclined in the same manner as the front surface of the first convex portion 41T and the rear surface of the second convex portion 42T.

[0059] [Connecting rod parts]

[0060] Link member 43 (see Figures 16 to 18 ) is fixed to the inner side of the inner cover 3C and swings together with the inner cover 3C when the inner cover 3C is opened or closed. The connecting member 43 has an axial hole portion 43A and a groove 43V, wherein the axial hole portion 43A is coaxially supported with the hinge 3H of the inner cover 3C, and the groove 43V slides relative to the top end portion of the protrusion 42B when the inner cover 3C is opened or closed. The groove 43V has a first section 43V1 and a second section 43V2, wherein the first section 43V1 is an arc shape centered on the axis of the hinge 3H, and the second section 43V2 is continuous with the first section 43V1 and has a smaller curvature radius than the first section 43V1. The second section 43V2 is connected to the end of the first section 43V1 on the inner cover 3C side.

[0061] Next, the opening and closing operation of the inner cover 3C will be described. Fig.15 , Fig.18Indicates the state in which the inner cover 3C is fully opened. The developing device 14 is installed and removed in the state in which the inner cover 3C is fully opened. The protrusion 42B of the lower guide rail 42 is located at the end of the first section 43V1 of the groove 43V of the connecting rod member 43 on the side of the developing device 14. At this time, the lower guide rail 42 is located at the position where it is pulled out to the front. This position is called the first position.

[0062] In the first position, the second protrusion 42T of the lower guide rail 42 is located in front of the first protrusion 41T of the upper guide rail 41 and enters the recess 41U of the upper guide rail 41. That is, the second protrusion 42T does not contact the first protrusion 41T. In addition, the rod-shaped member 41GB of the guide member 41G of the upper guide rail 41 is located in the axial portion 42KA of the notch portion 42K of the lower guide rail 42. At this time, the upper guide rail 41 is in a state closest to the lower guide rail 42, as shown in FIG. Figure 8 As shown, the developing roller 32 is farthest from the photosensitive drum 11 .

[0063] Fig.14 , Fig.17 Indicates a state where the projection 42B is located near the boundary between the first section 43V1 and the second section 43V2 of the 43V groove. The position of the inner cover 3C at this time is referred to as a predetermined position. When the inner cover 3C is swung within the range from the fully open position to the predetermined position, the first section 43V1 slides relative to the projection 42B while the lower guide rail 42 is kept at the first position. Since the lower guide rail 42 does not move, the relative positional relationship with the upper guide rail 41 does not change, and the posture of the developer holder 70 does not change.

[0064] Fig.13 , Fig.16 Indicates the state in which the inner cover 3C is completely closed. When the inner cover 3C is closed from the specified position to the fully closed position, the projection 42B enters the second area 43V2 of the groove 43V, so the projection 42B is pressed backward by the outer periphery of the second area 43V2, and the lower rail 42 also moves backward. When the inner cover 3C is completely closed, the lower rail 42 is located at the position where it is pressed to the rearmost. This position is referred to as the second position.

[0065] When the lower guide rail 42 is moved from the first position (refer to Fig.15 ) to the second position (reference Fig.13) moves, the rear surface of the second protrusion 42T moves rearward while sliding relative to the front surface of the first protrusion 41T. In addition, the rod-shaped member 41GB of the guide member 41G of the upper guide rail 41 moves rearward while sliding relative to the inclined portion 42KS of the notch portion 42K of the lower guide rail 42. Therefore, the upper guide rail 41 is gradually pushed upward, the lower surface of the first protrusion 41T climbs onto the upper surface of the second protrusion 42T, and the rod-shaped member 41GB climbs onto the upper surface of the lower guide rail 42. At this time, the upper guide rail 41 is in a state farthest from the lower guide rail 42, as shown in FIG. Figure 7 As shown, the developing roller 32 is closest to the photosensitive drum 11.

[0066] In the fully closed position (refer to Fig.13 ) to the specified position (refer to Fig.14 ) When the cover 3C is opened, the protrusion 42B is pressed forward by the inner peripheral portion of the second section 43V2 of the groove 43V, and the lower guide rail 42 also moves forward. When the inner cover 3C reaches the specified position, the lower guide rail 42 reaches the first position. When the lower guide rail 42 moves from the second position to the first position, the rear surface of the second protrusion 42T moves forward while sliding relative to the front surface of the first protrusion 41T. The rod-shaped part 41GB moves forward while sliding relative to the inclined portion 42KS of the notch portion 42K. Therefore, the upper guide rail 41 gradually descends and returns to the fully opened position (refer to Fig.15 ).

[0067] According to the image forming apparatus 100 according to the present embodiment described above, the drum unit 50 includes the photosensitive drum 11, the developing device 14 includes the developing roller 32, and the developing roller 32 is arranged so that its outer peripheral surface faces the outer peripheral surface of the photosensitive drum 11, the developing holder 70 can be detached from the developing device 14, and swings so that the developing roller 32 approaches and leaves the photosensitive drum 11, the lower guide 42 slides in the axial direction of the developing roller 32, the developing holder 70 is linked to the sliding of the lower guide 42 from the first position to the second position, so that the developing roller 32 is swung so that the photosensitive drum 11 is approached, and the developing holder 70 is linked to the sliding of the lower guide 42 from the second position to the first position, so that the developing roller 32 is swung so that the photosensitive drum 11 is separated. Therefore, the positioning of the developing device 14 can be easily and reliably performed with a simple structure.

[0068] In addition, according to the image forming apparatus 100 of the present embodiment, the lower guide rail 42 is provided below the developer holder 70, the developer holder 70 has the first convex portion 41T protruding downward, and the lower guide rail 42 has the second convex portion 42T protruding upward, when the lower guide rail 42 is located at the first position, the first convex portion 41T does not contact the second convex portion 42T, and when the lower guide rail 42 slides from the first position to the second position, the first convex portion 41T pushes the second convex portion 42T, so that the developer holder 70 is swung in such a manner that the developing roller 32 approaches the photosensitive drum 11. Therefore, the developer holder 70 can be swung in conjunction with the sliding of the lower guide rail 42 by a simple structure.

[0069] In addition, according to the image forming apparatus 100 involved in this embodiment, the opening portion 3A and the inner cover 3C (an example of a cover) are provided, wherein the opening portion 3A is used to insert the developing device 14, and the inner cover 3C is connected to the opening portion 3A through the hinge 3H and is connected to the lower guide rail 42. The lower guide rail 42 slides from the first position to the second position in conjunction with the action of closing the inner cover 3C, and the lower guide rail 42 slides from the second position to the first position in conjunction with the action of opening the inner cover 3C. Therefore, the developing device 14 can be easily and accurately positioned only by opening and closing the inner cover 3C.

[0070] In addition, according to the image forming apparatus 100 involved in this embodiment, there are a protrusion 42B, a link member 43 and a groove 43V, wherein the protrusion 42B protrudes from the end of the inner cover 3C side of the lower guide rail 42 toward the axial direction of the hinge 3H, the link member 43 is provided on the inner side of the inner cover 3C, and swings together with the inner cover 3C when the inner cover 3C is opened or closed, and the groove 43V is provided in the link member 43, and slides relative to the top end of the protrusion 42B when the inner cover 3C is opened or closed, and the groove 43V has a first section 43V1 and a second section 43V2, wherein the first section 43V1 is an arc shape centered on the axis of the hinge 3H, The second section 43V2 is continuous with the end of the first section 43V1 on the inner cover 3C side, and has a smaller curvature radius than the first section 43V1. When the inner cover 3C is swung from the fully open position to a predetermined position between the fully open position and the fully closed position, the first section 43V1 slides relative to the projection 42B while the lower guide rail 42 is kept at the first position. When the inner cover 3C is swung from the predetermined position to the fully closed position, the second section 43V2 slides relative to the projection 42B, thereby sliding the lower guide rail 42 between the first position and the second position. Therefore, since the lower guide rail 42 slides in a state where the axial component of the force for opening and closing the inner cover 3C is large, the effort required for opening and closing the inner cover 3C can be reduced.

[0071] The above-mentioned embodiment may be modified as follows.

[0072] In the above embodiment, an example is shown in which the rear surface of the second convex portion 42T slides relative to the front surface of the first convex portion 41T, but it is also possible to configure the rear end of the lower rail 42 to be inclined similarly to the rear surface of the second convex portion 42T, and the rear end of the lower rail 42 slides relative to the front surface of the first convex portion 41T. In this case, the second convex portion 42T is not required. With this structure, the same function as the above embodiment can be achieved.

[0073] In the above embodiment, the first protrusion 41T is provided on the lower surface of the upper rail 41, but the upper rail 41 may not be provided, and the first protrusion 41T may be provided on the lower surface of the developer holder 70. This structure can also achieve the same function as the above embodiment.

[0074] In the above embodiment, an example is shown in which the link member 43 has the shaft hole portion 43A supported coaxially with the hinge 3H of the inner cover 3C, but the link member 43 may not have the shaft hole portion 43A. With this structure, the same function as the above embodiment can be achieved. In addition, the structure with the shaft hole portion 43A can suppress the deformation of the inner cover 3C when opening and closing.

[0075] In the above-described embodiment, an example is shown in which the inner cover 3C is provided behind the outer cover 3B, but the outer cover 3B may also serve as the inner cover 3C.

Claims

1. An image forming device, It is characterized in that The invention comprises a drum unit, a developing device, a developing holding frame, a sliding member, an opening and a cover, wherein: The drum unit has a photosensitive drum, The developing device includes a developing roller, the developing roller being arranged such that its outer peripheral surface faces the outer peripheral surface of the photosensitive drum. The developing holding frame can be detached from the developing device and can swing in such a way that the developing roller approaches and moves away from the photosensitive drum. The sliding member slides in the axial direction of the developing roller. The opening is used to insert the developing device. The cover is engaged with the opening portion and connected to the sliding member via a hinge. The sliding member slides from the first position to the second position in conjunction with the action of closing the cover, and the sliding member slides from the second position to the first position in conjunction with the action of opening the cover. The developing holder and the sliding member slide from the first position to the second position in conjunction with each other so as to swing the developing roller close to the photosensitive drum. The developing holder and the sliding member slide from the second position to the first position in conjunction with each other so as to swing the developing roller away from the photosensitive drum. The image forming device has a protrusion, a link member and a groove, wherein: The projection protrudes from the cover-side end of the sliding member in the axial direction of the hinge. The link member is provided inside the cover and swings together with the cover when the cover is opened or closed. The groove is provided in the link member and slides relative to the tip of the projection when the cover is opened or closed. The groove has a first section and a second section, wherein The first section is an arc-shaped section centered on the axis of the hinge. The second section is continuous with the end of the first section on the cover side and has a smaller curvature radius than the first section. When the cover is swung within a range from the fully open position to a predetermined position, the first section slides relative to the protrusion when the sliding member is located at the first position, wherein the predetermined position is a position between the fully open position and the fully closed position. When the cover is swung within the range from the predetermined position to the fully closed position, the second section slides relative to the boss, whereby the sliding member slides between the first position and the second position.

2. The image forming apparatus according to claim 1, It is characterized in that The developer holding frame swings around a fulcrum provided below an end portion on a side close to the photosensitive drum.

3. The image forming apparatus according to claim 1, It is characterized in that The sliding member is disposed below the developing holding frame. The developing holding frame has a first protrusion protruding downward. The sliding member has a second protrusion protruding upward, When the sliding member is located at the first position, the first protrusion is not in contact with the second protrusion. When the sliding member slides from the first position to the second position, the first projection pushes up the second projection, so that the developing holder swings in such a manner that the developing roller approaches the photosensitive drum.

4. The image forming apparatus according to claim 1, It is characterized in that The connecting member is fixed to the inner side of the cover and swings around the hinge.

Images