Image-forming device

Abstract

To provide an image-forming device capable of smoothly attaching or detaching a developing device when maintaining or exchanging the developing device.SOLUTION: An image-forming device 1 comprises a developing device 40 and a slide member 82. The slide member 82 can be reciprocated in the longitudinal direction of the developing device 40 and supports the developing device 40 removably. The developing device 40 and the slide member 82 have a positioning pin 822d and a positioning hole 55 that are fitted when they approach mutually. The positioning hole 55 has an opening tilted section 55a tilted relative to an axial direction of the positioning hole 55. The positioning pin 822d has: an end tilted section 822da tilted relative to an axial direction of the positioning pin 822d; and a positioning tilted section 822db that is disposed opposite to the opening tilted section 55a in a longitudinal direction of the developing device 40 continuously in a circumferential direction of the end tilted section 822da, and has a smaller tilt angle than the end tilted section 822da.SELECTED DRAWING: Figure 17

Description

[Technical Field]

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

[0002] Electrophotographic image forming devices such as copiers and printers are equipped with a developing device that supplies toner to an electrostatic latent image formed on the outer surface of an image carrier such as a photosensitive drum, thereby developing the image into a toner image.The image forming device may detachably support the developing device for maintenance or replacement of the developing device.

[0003] The conventional image forming apparatus disclosed in Patent Document 1 includes a developer holder that holds a developing device. The developer holder can swing in a direction that moves the developing roller toward or away from the photosensitive drum. Before removing the developing device, the image forming apparatus swings the developer holder to move the developing roller away from the photosensitive drum. This prevents damage to the outer peripheral surface of the photosensitive drum. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-201459 Summary of the Invention [Problem to be solved by the invention]

[0005] When installing or removing a developing device in a conventional image forming apparatus, the support frame of the developing device holder may be moved toward the rear or front side as the front cover is closed or opened, bringing the developing device holder closer to or further away from the support frame. In other words, the longitudinal movement of the developing device holder and the installation or removal of the developing device holder relative to the support frame occur almost simultaneously as the front cover is opened or closed. However, the simultaneous relative movement of the developing device holder and the support frame in two different directions can make it difficult to insert or remove the pins and holes used to connect the developing device to the support frame. This raises concerns that smooth installation and removal of the developing device may be difficult.

[0006] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned points, and has as its object to provide an image forming apparatus in which a developing device can be smoothly attached and detached when the developing device is to be maintained or replaced. [Means for solving the problem]

[0007] To solve the above problems, the image forming apparatus of the present invention includes an image carrier, a developing device, a slide member, a contact / separation mechanism, a density sensor, and an interconnection board. An electrostatic latent image is formed on the outer peripheral surface of the image carrier. The developing device has a developer carrier that supplies toner to the electrostatic latent image to form a toner image. The slide member is reciprocally movable in the longitudinal direction of the developing device and detachably supports the developing device. The contact / separation mechanism moves the slide member in the longitudinal direction of the developing device between a support position approaching the developing device and a separated position away from the developing device. The density sensor is provided in the developing device and detects the toner density within the developing device. The interconnection board is provided on the slide member and is electrically connectable to the density sensor. The developing device and the slide member have either a positioning pin or a positioning hole that fit together when they approach each other. The positioning hole is provided at an opening end and has an opening inclined portion that is inclined with respect to the axial direction of the positioning hole. The positioning pin has a tip inclined portion and a positioning inclined portion. The tip inclined portion is provided at the tip of the positioning pin and is inclined with respect to the axial direction of the positioning pin. The positioning inclined portion is continuous with the tip inclined portion in the circumferential direction, is disposed opposite the opening inclined portion in the longitudinal direction of the developing device, and has a smaller inclination angle with respect to the axial direction than the tip inclined portion. [Effects of the Invention]

[0008] According to the configuration of the present invention, the positioning pin and the positioning hole each have an inclined opening portion and an inclined tip portion, so they fit easily when they approach each other. Furthermore, because the positioning pin has an inclined positioning portion, when the developing device moves in the longitudinal direction, the inclined positioning portion, which has a small inclination angle, comes into contact with the inclined opening portion and easily advances toward the positioning hole. Therefore, the developing device can be smoothly installed and removed when performing maintenance or replacement. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a schematic cross-sectional front view of an image forming apparatus according to an embodiment of the present invention; [Figure 2] 2 is a schematic cross-sectional front view of the periphery of the image forming unit of the image forming apparatus of FIG. 1, showing a state in which a developing device is disposed at a developing position. [Figure 3] 2 is a schematic cross-sectional front view of the periphery of the image forming unit of the image forming apparatus of FIG. 1, showing a state in which the developing device is placed at a retracted position. FIG. [Figure 4] FIG. 2 is a perspective view showing the arrangement of four image forming units in FIG. [Figure 5] 5 is a perspective view showing the arrangement of the four image forming units in FIG. 4 with the access cover open; FIG. [Figure 6] 5 is a vertical cross-sectional side view of the image forming unit of FIG. 4. [Figure 7] 7 is a vertical cross-sectional side view of the image forming unit in FIG. 6, showing a state in which the access cover is open. [Figure 8] 5 is a perspective view of the developing device of FIG. 4 as seen from below. [Figure 9] FIG. 9 is a partially enlarged perspective view of the periphery of a density sensor of the developing device in FIG. 8. [Figure 10] 5 is a partial perspective view of the slide member of the image forming unit of FIG. 4 as seen from above. [Figure 11] 11 is a partially enlarged perspective view of the periphery of the relay board of the sliding member of FIG. 10. FIG. [Figure 12] FIG. 12 is a perspective view of the relay board and the board holder of FIG. [Figure 13] 12 is a side view of the holder support portion of the slide member of FIG. 11. FIG. [Figure 14] 12 is a side view of the periphery of the holder support part in FIG. 11, showing a state in which the slide member is in a support position. FIG. [Figure 15] 14. FIG. 15 is a side view of the holder support section and its surroundings in FIG. 11, showing a state in which the slide member has moved to the front side from the state in FIG. [Figure 16] 15. FIG. 16 is a side view of the periphery of the holder support part in FIG. 11, showing a state in which the slide member has moved from the state in FIG. 15 to the front side and moved to the separated position. [Figure 17] FIG. 15 is a partial cross-sectional side view of the connection portion of FIG. [Figure 18] 18 is a partial cross-sectional side view of the connection portion of FIG. 17, showing a state in which a positioning pin is inserted into a positioning hole. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following.

[0011] Fig. 1 is a schematic cross-sectional front view of an image forming apparatus 1 according to an embodiment. Figs. 2 and 3 are schematic cross-sectional front views of the image forming unit 20 and its surroundings of the image forming apparatus 1 shown in Fig. 1, showing a state in which the developing device is disposed in a developing position and a retracted position. An example of the image forming apparatus 1 according to this embodiment is a tandem color printer that transfers a toner image onto a sheet S using an intermediate transfer belt 31. The image forming apparatus 1 may be a so-called multifunction device that has functions such as printing, scanning (image reading), and facsimile transmission.

[0012] As shown in Figures 1, 2 and 3, the image forming apparatus 1 includes a sheet supply unit 3, a sheet conveying unit 4, an exposure unit 5, an image forming unit 20, a transfer unit 30, a fixing unit 6, a sheet discharge unit 7 and a control unit 8, which are provided in a main body 2.

[0013] The sheet supply unit 3 is located at the bottom of the main body 2. The sheet supply unit 3 stores multiple sheets S before printing, and separates and sends out the sheets S one by one during printing. The sheet conveying unit 4 extends in the vertical direction along the side wall of the main body 2. The sheet conveying unit 4 conveys the sheet S sent out from the sheet supply unit 3 to the secondary transfer unit 33 and the fixing unit 6, and then discharges the sheet S after fixing from the sheet discharge port 4a to the sheet discharge unit 7.

[0014] The exposure unit 5 is disposed above the sheet supply unit 3. The exposure unit 5 irradiates the image forming unit 20 with laser light controlled based on image data.

[0015] The image forming units 20 are disposed above the exposure unit 5 and below the intermediate transfer belt 31. The image forming units 20 include an image forming unit 20Y for yellow, an image forming unit 20C for cyan, an image forming unit 20M for magenta, and an image forming unit 20B for black. These four image forming units 20 have the same basic configuration. Therefore, in the following description, the identification symbols "Y," "C," "M," and "B" representing each color may be omitted unless otherwise specified.

[0016] The image forming unit 20 includes a photosensitive drum (image carrier) 21 that is supported so as to be rotatable in a predetermined direction (clockwise in FIGS. 1 and 2). The image forming unit 20 further includes a charging unit 22, a developing device 40, and a drum cleaning unit 23 that are arranged around the photosensitive drum 21 along the direction of rotation of the photosensitive drum 21. A primary transfer unit 32 is arranged between the developing device 40 and the drum cleaning unit 23.

[0017] The photosensitive drum 21 is formed in a cylindrical shape extending horizontally and has a photosensitive layer formed of, for example, an amorphous silicon photosensitive material on its outer circumferential surface. The charging unit 22 charges the surface (outer circumferential surface) of the photosensitive drum 21 to a predetermined potential. The exposure unit 5 exposes the outer circumferential surface of the photosensitive drum 21 charged by the charging unit 22 to light, forming an electrostatic latent image of the original image on the outer circumferential surface of the photosensitive drum 21. The developing device 40 supplies toner to this electrostatic latent image to develop it into a toner image. Each of the four image forming units 20 forms a toner image of a different color. The drum cleaning unit 23 removes and cleans any toner remaining on the outer circumferential surface of the photosensitive drum 21 after the toner image has been primarily transferred to the outer circumferential surface of the intermediate transfer belt 31. In this way, the image forming unit 20 forms an image (toner image) that will later be transferred to the sheet S.

[0018] The transfer unit 30 includes an intermediate transfer belt 31, primary transfer units 32Y, 32C, 32M, and 32B, a secondary transfer unit 33, and a belt cleaning unit 34. The intermediate transfer belt 31 is disposed above the four image forming units 20. The intermediate transfer belt 31 is supported so as to be rotatable in a predetermined direction (counterclockwise in FIG. 1), and is an endless intermediate transfer body onto which the toner images formed by each of the four image forming units 20 are sequentially superimposed and primarily transferred. The four image forming units 20 are disposed in a so-called tandem arrangement, lined up in a row from the upstream side to the downstream side in the rotation direction of the intermediate transfer belt 31.

[0019] Primary transfer units 32Y, 32C, 32M, and 32B are disposed above image forming units 20Y, 20C, 20M, and 20B of the respective colors, with intermediate transfer belt 31 sandwiched therebetween. Secondary transfer unit 33 is disposed upstream of fixing unit 6 in the sheet conveying direction of sheet conveying unit 4, and downstream of four image forming units 20Y, 20C, 20M, and 20B in the rotation direction of intermediate transfer belt 31. Belt cleaning unit 34 is disposed downstream of secondary transfer unit 33 in the rotation direction of intermediate transfer belt 31.

[0020] The primary transfer unit 32 transfers the toner image formed on the outer circumferential surface of the photosensitive drum 21 onto the intermediate transfer belt 31. In other words, the toner image is primarily transferred onto the outer circumferential surface of the intermediate transfer belt 31 at the primary transfer units 32Y, 32C, 32M, and 32B for each color. Then, as the intermediate transfer belt 31 rotates, the toner images of the four image forming units 20 are successively superimposed and transferred onto the intermediate transfer belt 31 at a predetermined timing, thereby forming a color toner image on the outer circumferential surface of the intermediate transfer belt 31 in which toner images of four colors, yellow, cyan, magenta, and black, are superimposed.

[0021] The color toner image on the outer circumferential surface of the intermediate transfer belt 31 is transferred to the sheet S, which is fed synchronously by the sheet conveying unit 4, at a secondary transfer nip formed in the secondary transfer unit 33. The belt cleaning unit 34 removes and cleans the toner and other adhering matter remaining on the outer circumferential surface of the intermediate transfer belt 31 after the secondary transfer. In this way, the transfer unit 30 transfers (records) the toner image formed on the outer circumferential surface of the photosensitive drum 21 onto the sheet S.

[0022] The fixing unit 6 is disposed above the secondary transfer unit 33. The fixing unit 6 fixes the toner image to the sheet S by applying heat and pressure to the sheet S onto which the toner image has been transferred.

[0023] The sheet discharge section 7 is disposed above the transfer section 30. The sheet S on which the toner image has been fixed and printing has been completed is transported to the sheet discharge section 7. The sheet discharge section 7 takes out the printed sheet (printed material) from above.

[0024] The control unit 8 includes a CPU, an image processing unit, a memory unit, and other electronic circuits and electronic components (all not shown). The CPU controls the operation of each component provided in the image forming apparatus 1 based on control programs and data stored in the memory unit to perform processing related to the functions of the image forming apparatus 1. The sheet supply unit 3, the sheet conveying unit 4, the exposure unit 5, the image forming unit 20, the transfer unit 30, and the fixing unit 6 each receive individual commands from the control unit 8 and work together to print on the sheet S. The memory unit is configured by a combination of a non-volatile storage device such as a program ROM (Read Only Memory) or a data ROM, and a volatile storage device such as a RAM (Random Access Memory).

[0025] Next, the configuration of the developing device 40 will be described with reference to Figures 2 and 3. Note that the developing devices 40 for each color have the same basic configuration, so the identification symbols representing each color for the components will not be listed or described. In addition, in this description, the "axial direction" refers to the axial direction of rotation of the photosensitive drum 21, first transport member 42, second transport member 43, and developing roller 44, which extend parallel to one another (the direction into the paper in Figures 2 and 3).

[0026] The developing device 40 supplies toner to the outer peripheral surface of the photosensitive drum 21. The developing device 40 is detachable from, for example, the main body 2 of the image forming apparatus 1. The developing device 40 includes a developer container 50, a first transport member 42, a second transport member 43, a developing roller (developer carrier) 44, a regulating blade 45, and a concentration sensor 46.

[0027] The developing container 50 has an elongated shape extending along the axial direction of the photosensitive drum 21, and is disposed with its longitudinal direction horizontal. In other words, the longitudinal direction of the developing container 50 is parallel to the axial direction of the photosensitive drum 21. The developing container 50 contains, as the developer containing toner to be supplied to the photosensitive drum 21, for example, a two-component developer containing toner and a magnetic carrier.

[0028] The developing container 50 has a partition portion 51, a first transport chamber 52, a second transport chamber 53, a pair of communication portions (not shown), and a pair of developing support shafts 54.

[0029] The partition portion 51 is provided at the lower part inside the developing container 50. The partition portion 51 is disposed at approximately the center in a direction intersecting the longitudinal direction of the developing container 50 (the left-right lateral direction in FIGS. 2 and 3). The partition portion 51 is formed in a generally plate shape extending in the longitudinal direction and the up-down direction of the developing container 50. The partition portion 51 divides the inside of the developing container 50 in a direction intersecting the longitudinal direction.

[0030] The first transport chamber 52 and the second transport chamber 53 are provided inside the developing container 50. The first transport chamber 52 and the second transport chamber 53 are formed by dividing the inside of the developing container 50 by a partition 51. The first transport chamber 52 and the second transport chamber 53 are arranged in parallel at approximately the same height.

[0031] The second transport chamber 53 is located adjacent to the photosensitive drum 21 and includes an area within the developer container 50 where the developing roller 44 is disposed. The first transport chamber 52 is located in an area within the developer container 50 that is farther away from the photosensitive drum 21 than the second transport chamber 53. A developer supply port (not shown) is opened in the first transport chamber 52, and developer is supplied to the developer container 50 through the developer supply port. In the first transport chamber 52, the first transport member 42 transports the developer from the rear side to the front side of the developer container 50 (from the rear side to the front side in the depth direction of the paper in FIGS. 2 and 3). In the second transport chamber 53, the second transport member 43 transports the developer from the front side to the rear side of the developer container 50 (from the front side to the rear side in the depth direction of the paper in FIGS. 2 and 3).

[0032] The pair of communication portions are disposed on the outer sides of both longitudinal ends of the partition portion 51. The communication portions communicate the first transport chamber 52 and the second transport chamber 53 in a direction intersecting the longitudinal direction of the partition portion 51 (the left-right lateral direction in FIGS. 2 and 3), i.e., in the thickness direction of the approximately plate-shaped partition portion 51. The pair of communication portions communicate the first transport chamber 52 and the second transport chamber 53 at both longitudinal end sides of the first transport chamber 52 and the second transport chamber 53. At the communication portion at the downstream end of the first transport chamber 52 in the developer transport direction, the developer is transported from the first transport chamber 52 side toward the second transport chamber 53 side. At the communication portion at the downstream end of the second transport chamber 53 in the developer transport direction, the developer is transported from the second transport chamber 53 side toward the first transport chamber 52 side.

[0033] The first transport member 42 is disposed in the first transport chamber 52. The second transport member 43 is disposed in the second transport chamber 53. The first transport member 42 and the second transport member 43 are disposed in parallel with each other at approximately the same height. The second transport member 43 extends in close proximity to and parallel to the developing roller 44. The first transport member 42 and the second transport member 43 are supported by the developing container 50 so as to be rotatable about an axis extending horizontally parallel to the developing roller 44.

[0034] The first transport member 42 and the second transport member 43 have the same basic configuration. The first transport member 42 and the second transport member 43 have spiral transport blades on the outer periphery of a rotation shaft extending along the longitudinal direction of the developing container 50. The first transport member 42 transports the developer from the rear side to the front side of the developing container 50 along the rotation axis in the first transport chamber 52 while stirring the developer. The second transport member 43 transports the developer from the front side to the rear side of the developing container 50 along the rotation axis in the second transport chamber 53 while stirring the developer. In other words, the first transport member 42 and the second transport member 43 transport the developer in opposite longitudinal directions while stirring the developer, and circulate it in a predetermined circulation direction.

[0035] The developing roller 44 is located above the second conveying member 43 inside the developing container 50 and is disposed opposite the photosensitive drum 21. The developing roller 44 is supported by the developing container 50 so as to be rotatable about an axis extending parallel to the axis of the photosensitive drum 21.

[0036] A portion of the outer circumferential surface of the developing roller 44 is exposed from the developing container 50, and faces and is close to the photosensitive drum 21. The developing roller 44 carries toner on its outer circumferential surface to be supplied to the outer circumferential surface of the photosensitive drum 21 in the region facing the photosensitive drum 21. The developing roller 44 carries toner in the second transport chamber 53 of the developing container 50 and supplies it to the photosensitive drum 21. In other words, the developing roller 44 causes the toner in the second transport chamber 53 to adhere to the electrostatic latent image on the outer circumferential surface of the photosensitive drum 21, thereby forming a toner image.

[0037] The regulating blade 45 is disposed upstream in the rotation direction of the developing roller 44 in the opposing region between the developing roller 44 and the photosensitive drum 21. The regulating blade 45 is disposed closely opposing the developing roller 44 with a predetermined gap between its tip and the outer circumferential surface of the developing roller 44. The regulating blade 45 extends over the entire area of ​​the developing roller 44 in the axial direction. The regulating blade 45 regulates the layer thickness of the developer carried on the outer circumferential surface of the developing roller 44 that passes through the gap between the tip of the regulating blade 45 and the outer circumferential surface of the developing roller 44.

[0038] The concentration sensor 46 is disposed at the bottom of a wall portion along the longitudinal direction of the first transport chamber 52. The concentration sensor 46 is disposed opposite the first transport member 42. In this embodiment, a headless sensor is used as the concentration sensor 46. The concentration sensor 46, which is a headless sensor, has a detection surface embedded in the inner wall surface of the first transport chamber 52. In other words, the concentration sensor 46 is provided in the developing device 40 and detects the toner concentration in the developer in the developing device 40.

[0039] More specifically, the concentration sensor 46 is a magnetic permeability detection sensor that obtains the toner concentration (the mixture ratio of toner T to carrier C in the developer; T / C) by detecting changes in the magnetic permeability of the two-component developer. If the ratio of toner to carrier in the developer in the first transport chamber 52 changes, the magnetic permeability also changes, and the output signal of the concentration sensor 46 changes accordingly. Based on the sensor output signal received from the concentration sensor 46, the control unit 8 controls the start and stop of replenishment of developer (toner and carrier) to the developing device 40.

[0040] The developer in the developing container 50 circulates in a predetermined circulation direction between the first transport chamber 52 and the second transport chamber 53 through the communication portion due to the rotation of the first transport member 42 and the second transport member 43. At this time, the toner in the developing container 50 is stirred and charged, and is carried on the outer peripheral surface of the developing roller 44. The developer carried on the outer peripheral surface of the developing roller 44 has its layer thickness regulated by the regulating blade 45, and is then carried to the opposing region between the developing roller 44 and the photosensitive drum 21 due to the rotation of the developing roller 44. When a predetermined development voltage is applied to the developing roller 44, the toner in the developer carried on the outer peripheral surface of the developing roller 44 moves to the outer peripheral surface of the photosensitive drum 21 in the opposing region due to the potential difference with the surface (outer peripheral surface) of the photosensitive drum 21. As a result, the electrostatic latent image on the outer peripheral surface of the photosensitive drum 21 is developed with the toner.

[0041] The pair of development support shafts 54 are disposed at the bottom of the development container 50 on the photosensitive drum 21 side in a direction intersecting the longitudinal direction (the left-right lateral direction in FIGS. 2 and 3). Each of the pair of development support shafts 54 extends along the longitudinal direction (axial direction, the direction into the paper in FIGS. 2 and 3) toward the front side and the back side of the development container 50.

[0042] The developing container 50 (developing device 40) is supported to be swingable relative to a support frame 60 (described later) around the axes of a pair of developing support shafts 54. The developing device 40 can swing around the axes of the pair of developing support shafts 54 between a developing position (see FIG. 2) where the developing roller 44 approaches the photosensitive drum 21 and a retracted position (see FIG. 3) where the developing roller 44 is separated from the photosensitive drum 21.

[0043] Fig. 4 is a perspective view showing the arrangement of the four image forming units 20 in Fig. 1. Fig. 5 is a perspective view showing the arrangement of the four image forming units 20 in Fig. 4, showing a state in which the opening / closing cover 2c is open. Fig. 6 is a vertical cross-sectional side view of the image forming units 20 in Fig. 4. Fig. 7 is a vertical cross-sectional side view of the image forming units 20 in Fig. 6, showing a state in which the opening / closing cover 2c is open. As shown in Figs. 4, 5, 6 and 7, the image forming apparatus 1 includes the opening / closing cover 2c and a support frame 60.

[0044] The access cover 2c is disposed on the front side of the four image forming units 20. An exterior cover (not shown) of the main body 2 of the image forming apparatus 1 is provided on the front side of the access cover 2c. The access cover 2c is supported on the main body 2 so as to be rotatable in the up and down direction, with a hinge portion 2d provided at the bottom end and extending horizontally in the left-right direction as a fulcrum. The access cover 2c opens and closes openings provided on the front side of the four image forming units 20. The developing device 40 can be inserted or removed from the front side of the image forming apparatus 1 by opening the access cover 2c and passing through the opening.

[0045] The support frame 60 is disposed below each of the four image forming units 20. The support frame 60 is disposed facing the image forming units 20 in the up-down direction. The support frame 60 supports the developing devices 40 of each of the four image forming units 20 so that they can be individually attached and detached. The support frame 60 includes a developer holder 70 and a contact / separation mechanism 80.

[0046] The developer holders 70 are disposed below the four developing devices 40, respectively. The developer holders 70 are supported by the support frame 60 via shafts (not shown) that are coaxial with the pair of developer support shafts 54 of the developer container 50 so as to be swingable about the axes of the shafts. The developer holders 70 extend in the front-rear and left-right directions below the developer containers 50. The developer holders 70 hold the developing devices 40.

[0047] The contact / separation mechanism 80 is disposed below the development holder 70 of each of the four development devices 40. The contact / separation mechanism 80 moves the development device 40 between a development position where the development roller 22 is brought close to the photosensitive drum 21 and a retracted position where the development roller 44 is separated from the photosensitive drum 21. The contact / separation mechanism 80 has an upper convex portion 81, a slide member 82, a lower convex portion 83, and a link member 84.

[0048] The upper convex portion 81 is provided on the lower surface of the developer holder 70. The upper convex portion 81 protrudes downward from the lower surface of the developer holder 70. The contact / separation mechanism 80 has multiple upper convex portions 81. In this embodiment, three upper convex portions 81 are provided at intervals in the front-to-rear direction (the left-to-right lateral direction in Figures 6 and 7). The upper convex portion 81 is approximately rectangular parallelepiped in shape, has a flat upper surface, and has an inclined surface at the front that slopes downward from the front to the rear.

[0049] The slide member 82 is disposed below the developer holder 70 (developing device 40). The slide member 82 is disposed facing the developer holder 70 in the up-down direction. The slide member 82 extends in the front-rear and left-right directions below the developer holder 70. The slide member 82 is guided by a guide portion (not shown) that is provided on the support frame 60 and extends along the longitudinal direction of the developing device 40 (front-rear direction, left-right lateral direction in Figures 6 and 7), and is capable of reciprocating movement in the longitudinal direction of the developing device 40. The slide member 82 supports the developing devices 40 of each of the four image forming units 20 so that they can be individually attached and detached. In addition, a front end portion 82a of the slide member 82 is bent downward in a substantially L-shape and is connected to a link member 84.

[0050] The lower protrusion 83 is provided on the upper surface of the slide member 82. The lower protrusion 83 protrudes upward from the upper surface of the slide member 82. The lower protrusion 83 is arranged opposite the upper protrusion 81 in the up-down direction. That is, the contact / separation mechanism 80 has a plurality of lower protrusions 83, the same number as the upper protrusions 81. In this embodiment, three lower protrusions 83 are provided spaced apart in the front-to-rear direction (the left-to-right lateral direction in Figures 6 and 7). The lower protrusion 83 has a substantially rectangular parallelepiped shape, a flat upper surface, and an inclined surface at the rear that slopes upward from the rear to the front.

[0051] The link member 84 is provided on the open-close cover 2c and protrudes toward the developing device 40 on the rear side. A front end 82a of the slide member 82 is connected to the link member 84. The link member 84 reciprocates the slide member 82 in the front-to-rear direction (the longitudinal direction of the developing device 40, the left-to-right lateral direction in FIGS. 6 and 7) in conjunction with the movement of the open-close cover 2c. More specifically, when the open-close cover 2c is opened as shown in FIG. 7, the slide member 82 moves forward (toward the front). When the open-close cover 2c is closed as shown in FIG. 6, the slide member 82 moves backward (toward the rear).

[0052] When the open / close cover 2c is in the closed state (see FIG. 6), the slide member 82 is positioned at the rearmost position, with the upper convex portion 81 riding on the lower convex portion 83. As a result, the slide member 82 pushes up the developing device 40 around the axis of the developing support shaft 54 ​​via the developing holder 70, and moves the developing device 40 to the developing position (see FIG. 2).

[0053] When the open / close cover 2c is opened to a predetermined position (see FIG. 7), the slide member 82 moves forward from the position shown in FIG. 6, and the upper convex portion 81 slides down the inclined surface of the lower convex portion 83 and moves away from the lower convex portion 83. As a result, the slide member 82 pulls the developing device 40 down around the axis of the developing support shaft 54 ​​via the developing holder 70, and moves the developing device 40 to the retracted position (see FIG. 3).

[0054] As described above, the contact / separation mechanism 80 moves the slide member 82 in the longitudinal direction (front-to-back direction) of the developing device 40, thereby moving the developing device 40 between a developing position where the developing roller 44 is brought close to the photosensitive drum 21 and a retracted position where the developing roller 44 is moved away from the photosensitive drum 21.

[0055] Next, a configuration related to the electrical connection of the density sensor 46 will be described. FIG. 8 is a perspective view of the developing device 40 of FIG. 4, seen from below. FIG. 9 is a partially enlarged perspective view of the periphery of the density sensor 46 of the developing device 40 of FIG. 8. FIG. 10 is a partially enlarged perspective view of the sliding member 82 of the image forming unit 20 of FIG. 4, seen from above. FIG. 11 is a partially enlarged perspective view of the periphery of the relay board 821 of the sliding member 82 of FIG. 10. FIG. 12 is a perspective view of the relay board 821 and the board holder 822 of FIG. 11. FIG. 13 is a side view of the holder support portion 85 of the sliding member 82 of FIG. 11.

[0056] As shown in FIGS. 8, 9, 10, and 11, the image forming unit 20 includes a connection portion 24 for supplying electricity and communicating signals to the concentration sensor 46 of the developing device 40. The connection portion 24 is provided below the concentration sensor 46 of the developing container 50. In the connection portion 24, the slide member 82 includes an intermediate board 821, a board holder 822, and a holder support portion 85. In other words, the image forming unit 20 includes the connection portion 24 between the concentration sensor 46 and the intermediate board 821. Note that the developing holder 70 has an opening 71 at the connection portion 24 through which components related to the electrical connection of the concentration sensor 46 pass.

[0057] In the connection portion 24, the developing container 50 includes a sensor connector portion 46c, a positioning hole 55, and a rotation restriction hole 56.

[0058] The sensor connector portion 46c is disposed at the bottom of the first transport chamber 52 of the developing container 50. The sensor connector portion 46c protrudes downward relative to the concentration sensor 46. The sensor connector portion 46c is electrically connected to a board connector portion 821c of the relay board 821, which will be described later.

[0059] The positioning hole 55 is disposed behind (on the rear side of) the sensor connector portion 46c in the longitudinal direction (front-rear direction) of the developing device 40. The positioning hole 55 has a cylindrical shape, opens to the lower surface of the first transport chamber 52 of the developing container 50, and is recessed upward. A positioning pin 822d, which will be described later, is inserted into and fitted into the positioning hole 55.

[0060] The rotation restriction hole 56 is disposed in front (on the front side) of the sensor connector portion 46c in the longitudinal direction (front-rear direction) of the developing device 40. The rotation restriction hole 56 is an elongated hole whose cross section extends in the front-rear direction, and opens to the lower surface of the first transport chamber 52 of the developing container 50 and is recessed upward. A rotation restriction pin 822e, which will be described later, is inserted into and fitted into the rotation restriction hole 56.

[0061] The relay substrate 821 includes a substrate connector portion 821c. The substrate connector portion 821c is disposed on the upper surface of the relay substrate 821 and protrudes upward. The substrate connector portion 821c is electrically connected to a sensor connector portion 46c of the concentration sensor 46. In other words, the relay substrate 821 is provided on the sliding member 82 and is electrically connectable to the concentration sensor 46.

[0062] The substrate holder 822 is a frame-shaped member extending in the longitudinal direction (front-rear direction) of the developing device 40, and holds the relay substrate 821. The substrate holder 822 is supported movably relative to the holder support portion 85 of the slide member 82. The substrate holder 822 includes a pair of side plates 822a, a front upper plate 822b, a rear upper plate 822c, a positioning pin 822d, a rotation restriction pin 822e, and a pair of connecting shafts 822f.

[0063] The pair of side plates 822a extend in the up-down and front-rear directions and are arranged opposite each other in the left-right direction. The front upper plate 822b connects the upper ends of the pair of side plates 822a at the front side. The rear upper plate 822c connects the upper ends of the pair of side plates 822a at the rear side. The front upper plate 822b and the rear upper plate 822c are separated by a gap in the front-rear direction.

[0064] The relay board 821 is held inside a board holder 822, which is a frame-shaped member composed of a pair of side plates 822a, a front upper plate 822b, and a rear upper plate 822c. The board connector portion 821c protrudes upward from the gap between the front upper plate 822b and the rear upper plate 822c.

[0065] The positioning pin 822d is disposed behind (on the rear side of) the board connector portion 821c in the longitudinal direction (front-rear direction) of the developing device 40. The positioning pin 822d is cylindrical and is provided on the upper surface of the rear upper plate 822c, protruding upward. The positioning pin 822d is inserted into and fitted into the positioning hole 55.

[0066] The rotation restriction pin 822e is disposed in front (on the front side) of the board connector portion 821c in the longitudinal direction (front-rear direction) of the developing device 40. The rotation restriction pin 822e is formed, for example, as a protrusion having a cross-shaped cross section, and is provided on the upper surface of the front upper plate 822b, protruding upward. The rotation restriction pin 822e is inserted into and fitted into the rotation restriction hole 56.

[0067] The positioning pin 822d and the positioning hole 55 are provided for positioning the sensor connector portion 46c and the board connector portion 821c. Therefore, the positioning pin 822d and the positioning hole 55 preferably have circular cross sections that fit together.

[0068] Furthermore, the rotation restriction pin 822e and the rotation restriction hole 56 are disposed at a distance from the positioning pin 822d and the positioning hole 55 in the longitudinal direction (front-rear direction) of the developing device 40. This makes it possible to restrict rotation of the sensor connector portion 46c and the board connector portion 821c about the axes of the positioning pin 822d and the positioning hole 55. For this reason, the rotation restriction pin 822e and the rotation restriction hole 56 may have any shape that can restrict their displacement in the left-right lateral directions.

[0069] The pair of connecting shafts 822f are provided on the pair of side plates 822a. Each of the pair of connecting shafts 822f protrudes toward the outside of each of the pair of side plates 822a and extends horizontally in the left-right direction. The pair of connecting shafts 822f are inserted into a pair of guide grooves 853 of the holder support part 85, which will be described later.

[0070] The holder support portion 85 is provided on the slide member 82. The holder support portion 85 includes a base portion 851, a pair of guide walls 852, and a pair of guide grooves 853.

[0071] The base portions 851 are arranged at two locations spaced apart in the front-to-rear direction. The base portions 851 are substantially rectangular parallelepiped-shaped, with a flat upper surface and an inclined surface at the rear that slopes upward from the rear to the front.

[0072] The pair of guide walls 852 are located between the two base portions 851 in the front-rear direction and are arranged on both outer sides of the base portion 851 in the left-right lateral direction. The pair of guide walls 852 extend in the up-down direction and the front-rear direction and are arranged opposite each other in the left-right lateral direction. The distance between the pair of guide walls 852 is longer than the width of the substrate holder 822. The substrate holder 822 is arranged between the pair of guide walls 852.

[0073] The pair of guide grooves 853 are formed in the pair of guide walls 852, penetrate the guide walls 852 in the left-right direction, and extend in the front-rear direction. The pair of guide grooves 853 have horizontal portions parallel to the upper surface of the base portion 851 and inclined portions that slope downward from the rear ends of the horizontal portions toward the rear. The angle of the inclined portions of the guide grooves 853 relative to the horizontal direction is the same as the angle of the inclined surfaces of the base portion 851 relative to the horizontal direction.

[0074] A pair of connecting shafts 822f of the substrate holder 822 are inserted into the pair of guide grooves 853. In this way, the holder support portion 85 supports the substrate holder 822 so that it can move in the front-rear direction.

[0075] Next, a connection operation between the sensor connector portion 46c of the concentration sensor 46 and the board connector portion 821c of the relay board 821 will be described. FIG. 14 is a side view of the holder support portion 85 and its periphery in FIG. 11, illustrating a state in which the slide member 82 is in the separated position. FIG. 15 is a side view of the holder support portion 85 and its periphery in FIG. 11, illustrating a state in which the slide member 82 has moved rearward from the state in FIG. 14. FIG. 16 is a side view of the holder support portion 85 and its periphery in FIG. 11, illustrating a state in which the slide member 82 has moved rearward from the state in FIG. 15 to the support position. Note that in FIGS. 14, 15, and 16, the left side is the front (front side) of the developing device 40 and the slide member 82, and the right side is the rear (rear side) of the developing device 40 and the slide member 82.

[0076] 14, when the open-close cover 2c is in the open state, the slide member 82 is positioned in the front (left side in FIG. 14), and the pair of connecting shafts 822f of the substrate holder 822 are positioned in the rearmost position (right side in FIG. 14) of the pair of guide grooves 853 of the holder support portion 85. The relay board 821 and the substrate holder 822 are spaced below the developing device 40. In other words, the slide member 82 is positioned in a spaced position spaced from the developing device 40.

[0077] At this time, the contact / separation mechanism 80 places the developing device 40 in a retracted position where the developing roller 44 is separated from the photosensitive drum 21. That is, when the opening / closing cover 2c is in the open state, the contact / separation mechanism 80 moves the slide member 82 to a separated position where the slide member 82 is separated from the developing device 40.

[0078] When the open-close cover 2c is closed to a predetermined position, as shown in FIG. 15, the slide member 82 moves rearward from the position shown in FIG. 14, the pair of connecting shafts 822f rise up the inclined portions of the pair of guide grooves 853, and the board holder 822 rides up onto the rear pedestal portion 851. The board connector portion 821c is electrically connected to the sensor connector portion 46c. The positioning pin 822d is inserted into and fitted into the positioning hole 55. The rotation restriction pin 822e is inserted into and fitted into the rotation restriction hole 56. As a result, the relay board 821 and the board holder 822 are connected to the underside of the developing device 40.

[0079] 16, when the open / close cover 2c is closed, the slide member 82 moves rearward from the position shown in FIG. 15, the pair of connecting shafts 822f move along the horizontal portions of the pair of guide grooves 853, and the substrate holder 822 rides up onto the front pedestal portion 851. With the substrate connector portion 821c and the sensor connector portion 46c electrically connected, the relay substrate 821 is held below the lower surface of the developing container 50. The slide member 82 is positioned at a support position close to the developing device 40.

[0080] At this time, the contact / separation mechanism 80 places the developing device 40 at a development position where the developing roller 44 approaches the photosensitive drum 21. That is, by closing the open / close cover 2c, the contact / separation mechanism 80 moves the slide member 82 to a support position where the slide member 82 approaches the developing device 40.

[0081] Furthermore, when opening the open-close cover 2c that is in the closed state, the operations are reversed to those described above with reference to Figures 14, 15, and 16. As a result, the slide member 82 that is positioned in the support position moves to the separated position, and the electrical connection between the sensor connector portion 46c and the board connector portion 821c is released.

[0082] As described above, the contact / separation mechanism 80 moves the slide member 82 in the longitudinal direction (front-rear direction) of the developing device 40, between a support position where it approaches the developing device 40 and a separated position where it is separated from the developing device 40.

[0083] In other words, the contact / separation mechanism 80 moves the developing roller 44 closer to the photosensitive drum 21 when the slide member 82 is located in the support position, and moves the developing roller 44 away from the photosensitive drum 21 when the slide member 82 is located in the separated position. With this configuration, the developing device 40 can be supported by the slide member 82 and the developing device 40 can be positioned at the development position simultaneously. Also, the developing device 40 can be separated from the slide member 82 and the developing device 40 can be positioned at the retracted position simultaneously. This allows the developing device 40 to be attached and detached efficiently, reducing the number of parts and costs.

[0084] Next, details of the connection portion 24 between the concentration sensor 46 and the relay board 821 will be described. Fig. 17 is a partial cross-sectional side view of the connection portion 24 in Fig. 14. Fig. 18 is a partial cross-sectional side view of the connection portion 24 in Fig. 17, showing the state in which the positioning pin 822d is inserted into the positioning hole 55.

[0085] The positioning hole 55 has an opening inclined portion 55a. The opening inclined portion 55a is provided at the lower end of the positioning hole 55, at the opening end. The opening inclined portion 55a is formed in an annular shape along the circumferential direction of the cylindrical positioning hole 55. The opening inclined portion 55a is inclined with respect to the axial direction of the positioning hole 55 (the up-and-down direction in Figures 17 and 18). For example, the opening inclined portion 55a has an inclination angle α of 45 degrees with respect to the axial direction of the positioning hole 55.

[0086] The positioning pin 822d has a tip inclined portion 822da and a positioning inclined portion 822db.

[0087] The inclined tip portion 822da is provided at the upper end of the positioning pin 822d, at its tip. The inclined tip portion 822da is formed in a substantially annular shape along the circumferential direction of the cylindrical positioning pin 822d. The inclined tip portion 822da is inclined with respect to the axial direction of the positioning pin 822d (the up-and-down direction in FIGS. 17 and 18). For example, the inclined tip portion 822da has an inclination angle β of 45 degrees with respect to the axial direction of the positioning pin 822d.

[0088] The positioning inclined portion 822db is formed circumferentially continuous with the tip inclined portion 822da and in a portion of the circumferential direction. Specifically, the positioning inclined portion 822db is disposed opposite the opening inclined portion 55a in the longitudinal direction (front-rear direction, left-right lateral direction in FIGS. 17 and 18) of the developing device 40. The positioning inclined portion 822db faces in the longitudinal direction (front-rear direction) of the developing device 40 in the direction in which the slide member 82 moves from the separated position to the support position, i.e., toward the rear (rightward in FIGS. 17 and 18). The positioning inclined portion 822db has an inclination angle γ that is smaller than the inclination angle β of the tip inclined portion 822da with respect to the axial direction of the positioning pin 822d (γ<β).

[0089] According to the above configuration, the positioning pin 822d and the positioning hole 55 each have the inclined tip portion 822da and the inclined opening portion 55a, so that they can easily fit together when they approach each other. Furthermore, because the positioning pin 822d has the inclined positioning portion 822db, when the developing device 40 moves in the longitudinal direction (the direction of arrow A in FIG. 18), the inclined positioning portion 822db, which has a small inclination angle, comes into contact with the inclined opening portion 55a and easily moves toward the positioning hole 55 (the direction of arrow B in FIG. 18). Therefore, when the developing device 40 is maintained or replaced, the developing device 40 can be smoothly attached and detached.

[0090] Furthermore, as in the above configuration, for example, opening inclined portion 55a has an inclination angle α of 45 degrees and tip inclined portion 822da has an inclination angle β of 45 degrees, which makes it easier for positioning pin 822d to enter positioning hole 55. Then, by setting positioning inclined portion 822db to an inclination angle γ that is smaller than 45 degrees, it is possible to enhance the effect of positioning pin 822d moving toward the radial center of positioning hole 55 when positioning inclined portion 822db comes into contact with opening inclined portion 55a. Therefore, it becomes easier for positioning pin 822d to enter positioning hole 55, and it becomes possible to improve the accuracy of connection between board connector portion 821c and sensor connector portion 46c.

[0091] Furthermore, as configured above, the connection portion 24 between the density sensor 46 and the relay board 821 is disposed between the positioning pin 822d and the positioning hole 55 and the rotation restriction pin 822e and the rotation restriction hole 56 in the longitudinal direction (front-rear direction) of the developing device 40. This configuration improves the positioning accuracy of the connection portion 24, i.e., the board connector portion 821c and the sensor connector portion 46c, in the front-rear direction and the left-right lateral direction. This allows for optimal power supply and signal communication to the density sensor 46.

[0092] 15 and 16, the positioning pin 822d and the positioning hole 55 are engaged with each other before the slide member 82 moves to the support position close to the developing device 40, and are disengaged from each other before the slide member 82 moves to the separated position away from the developing device 40. According to this configuration, the positioning of the board connector portion 821c and the sensor connector portion 46c is completed before the connection between the board connector portion 821c and the sensor connector portion 46c is completed. Therefore, it is possible to improve the accuracy of the electrical connection between the board connector portion 821c and the sensor connector portion 46c.

[0093] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these, and various modifications can be made without departing from the spirit of the invention.

[0094] For example, in the above embodiment, the image forming apparatus 1 is a so-called tandem type image forming apparatus for color printing that forms images of multiple colors by sequentially overlapping them, but the image forming apparatus is not limited to this type. The image forming apparatus may be a non-tandem type image forming apparatus for color printing or a monochrome image forming apparatus. [Industrial Applicability]

[0095] The present invention can be used in an image forming apparatus. [Explanation of symbols]

[0096] 1. Image forming device 2 Main unit 2c Opening and closing cover 20 Image forming unit 21 Photosensitive drum (image carrier) 40 Developing device 44 Developing roller (developer carrier) 46 Concentration sensor 46c Sensor connector 50 Developer container 54 Developing shaft 55 Positioning hole 55a Opening slope 56 Rotation restriction hole 60 Support Frame 70 Developer holder 80 Approach / separation mechanism 81 Upper convex part 82 Slide member 83 Lower convex part 821 Relay board 821c PCB connector 822 PCB holder 822d Locating Pin 822da Tip inclined part 822db positioning inclined section 822e Rotation control pin

Claims

1. an image carrier on whose outer circumferential surface an electrostatic latent image is formed; a developing device having a developer carrier that supplies toner to the electrostatic latent image to form a toner image; a slide member that is reciprocally movable in the longitudinal direction of the developing device and that detachably supports the developing device; a contact / separation mechanism that moves the slide member in the longitudinal direction of the developing device between a support position where the slide member approaches the developing device and a separation position where the slide member is separated from the developing device; a concentration sensor provided in the developing device and detecting a toner concentration in the developing device; a relay board provided on the slide member and electrically connectable to the concentration sensor; Equipped with the developing device and the slide member have either a positioning pin or a positioning hole that fit together when they approach each other; the positioning hole has an opening inclined portion provided at an opening end and inclined with respect to an axial direction of the positioning hole, The positioning pin is a tip inclined portion provided at a tip end of the positioning pin and inclined with respect to an axial direction of the positioning pin; a positioning inclined portion that is continuous with the tip inclined portion in a circumferential direction and faces the opening inclined portion in the longitudinal direction of the developing device, and has an inclination angle with respect to the axial direction smaller than that of the tip inclined portion; An image forming apparatus comprising:

2. the opening inclined portion has an inclination angle of 45 degrees with respect to the axial direction of the positioning hole, the inclined tip portion has an inclination angle of 45 degrees with respect to the axial direction of the positioning pin, 2. The image forming apparatus according to claim 1, wherein the positioning inclined portion has an inclination angle of less than 45 degrees with respect to the axial direction of the positioning pin.

3. The image forming apparatus according to claim 1, characterized in that the developing device and the slide member are positioned away from the positioning pin and the positioning hole in the longitudinal direction of the developing device, and have either a rotation control pin or a rotation control hole that engage with each other when they approach each other.

4. 4. An image forming apparatus according to claim 3, wherein the connection portion between the density sensor and the relay board is arranged between the positioning pin and the positioning hole and the rotation restriction pin and the rotation restriction hole in the longitudinal direction of the developing device.

5. 2. The image forming apparatus according to claim 1, wherein the contact / separation mechanism brings the developer carrier closer to the image carrier when the slide member is positioned at the support position, and separates the developer carrier from the image carrier when the slide member is positioned at the separated position.

6. 6. An image forming apparatus according to claim 1, wherein the positioning pin and the positioning hole are engaged with each other before the slide member moves to the support position, and the engagement between the positioning pin and the positioning hole is released before the slide member moves to the separated position.

Images