JP4735770B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a laser printer.

  In general, as an electrophotographic image forming apparatus such as a laser printer, a photosensitive unit having a plurality of photosensitive drums and a developing unit (developing tray) having a plurality of developing units are provided. Is configured to be detachable from the apparatus main body (see Patent Document 1).

JP 2006-184553 A (FIGS. 1 to 4)

  However, in the above apparatus, when the developing unit is removed from the apparatus main body, the developing unit of the developing unit is separated from the photosensitive drum by separating the entire developing unit from the photosensitive unit, and then the developing unit. It was necessary to pull out the unit from the main body. For this reason, there is a problem that a large mechanism for moving the developing unit while supporting the weight of the whole developing unit is required.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image forming apparatus in which the developing unit can be pulled out from the apparatus main body with a simple mechanism.

In order to achieve the above object, an image forming apparatus of the present invention includes a photosensitive unit having a plurality of photosensitive drums, a plurality of developing units provided corresponding to the plurality of photosensitive drums and having developing rollers, And a developing unit that can be pulled out from the apparatus main body in the arrangement direction of the plurality of photosensitive drums, and the plurality of developing units are arranged in the supporting member. A developing position where the developing roller is close to the photosensitive drum, and a pulling position where the developing roller is separated from the photosensitive drum more than the developing position and the developing unit can be pulled out from the apparatus main body. And the plurality of developing devices are configured to stop and be supported at an intermediate position between the developing position and the drawing position, and Light body unit, said engaged with the developing device, the groove for positioning the movement of the developing device with guides between said intermediate position and said developing position a position of the developing unit relative to the photosensitive drum formed In the drawing position of the developing device, the engagement between the developing device and the groove is released.

According to the image forming apparatus configured as described above, each of the plurality of developing units includes a developing position in the support member where the developing roller is close to the photosensitive drum, and the developing roller is closer to the photosensitive drum than the developing position. since between the extended position away is movably supported, in deriving the developing unit from the apparatus main body may be pulled out of the developing unit in a state of being moved to a position pulled out a plurality of developing devices. This eliminates the need for a large-scale mechanism that moves while supporting the weight of the entire developer unit.

According to the image forming apparatus of the present invention, since a large-scale mechanism that moves while supporting the weight of the entire developing unit is unnecessary, the developing unit can be pulled out from the apparatus main body with a simple mechanism.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a cross-sectional view showing a schematic configuration of a color multifunction peripheral as an example of an image forming apparatus. 2A and 2B are diagrams for explaining the color development position of the developing unit, in which FIG. 2A is a diagram illustrating an external structure of the photosensitive unit and the developing unit, and FIG. 2B is a partially enlarged view of FIG. (C) is a diagram showing the internal structure of the photoreceptor unit and the developing unit. 3A and 3B are diagrams for explaining an intermediate position of the developing unit, in which FIG. 3A is a diagram illustrating an external structure of the photosensitive unit and the developing unit, FIG. 3B is a partially enlarged view of FIG. c) is a diagram showing the internal structure of the photoreceptor unit and the developing unit. 4A and 4B are diagrams for explaining the attachment / detachment positions of the developing unit, where FIG. 4A is a diagram showing the external structure of the photosensitive unit and the developing unit, FIG. 4B is a partially enlarged view of FIG. (c) is a diagram showing the internal structure of the photosensitive unit and the developing unit, and (d) is an enlarged view of the lock engaging portion. 5A and 5B are diagrams for explaining the monochrome development position of the developing unit, where FIG. 5A is a diagram illustrating the external structure of the photosensitive unit and the developing unit, and FIG. 5B is a partially enlarged view of FIG. (C) is a diagram showing the internal structure of the photoreceptor unit and the developing unit.

  Here, in the following description, the direction will be described with reference to the user when using the color multifunction peripheral. That is, in FIG. 1, the right side toward the paper surface is “front side”, the left side toward the paper surface is “rear side”, the back side toward the paper surface is “right side”, and the front side toward the paper surface is “left side”. To do. In addition, the vertical direction toward the page is defined as the “vertical direction”.

  As shown in FIG. 1, the color multifunction peripheral 1 mainly includes a main body case 2 as an example of an apparatus main body, and a flat bed scanner 3 provided above the main body case 2. Further, the color multifunction peripheral 1 includes a paper feed unit 4 that supplies a sheet P as an example of a recording sheet, an image forming unit 5 that forms an image on the fed paper P, and an image A paper discharge roller 6 that discharges the formed paper P and an exposure device 7 that exposes the photosensitive drum 32 are mainly provided.

  A front cover 2 </ b> A is provided on the front side of the main body case 2 so as to be pivotable back and forth with the lower part as a fulcrum. A paper discharge tray 2B for storing the paper P discharged from the main body case 2 is provided at the upper part of the main body case 2, and a rear cover 2C is provided at the rear side.

  The flatbed scanner 3 is an image reading device having a known configuration, and at the time of copying, generates image data by irradiating a document having an image with light and reading the image.

  The paper feeding unit 4 is provided in the lower part of the main body case 2 and is detachably attached to the main body case 2, and the separation provided in the main body case 2 at the upper rear side of the paper feeding cassette 71. The roller 72 and the paper feed rollers 73 to 75, the first conveyance roller 76 provided on the rear side of the photosensitive unit 30, and the second conveyance roller 77 provided so as to face the first conveyance roller 76 are mainly used. In preparation. The paper P in the paper feed cassette 71 is separated one by one by the separation roller 72, sent upward by the paper feed rollers 73 to 75, and passes between the first transport roller 76 and the second transport roller 77 to form an image. Supplied to the section 5 (between the intermediate transfer belt 51 and the secondary transfer roller 53).

  The image forming unit 5 mainly includes a photoconductor unit 30, a developing unit 40, a transfer unit 50, and a fixing unit 60.

  As shown in FIG. 2C, the photoconductor unit 30 includes a support frame 31 constituting an outer frame, four photoconductor drums 32, and a scorotron charger 33. The support frame 31 has openings on the top and bottom. In a state where the photoconductor unit 30 is mounted on the main body case 2, the photoconductor drum 32 is in contact with the primary transfer roller 52 via the intermediate transfer belt 51 in the upper portion thereof and in contact with the developing roller 42A in the oblique lower portion thereof.

As shown in FIG. 2C, the developing device unit 40 includes a support member 41 and a developing cartridge 42 as an example of a developing device.

  The support member 41 includes a support frame 41A that constitutes an outer frame, and a developing device holder 41B that supports the developing cartridge 42. The developing device holder 41B detachably accommodates the developing cartridge 42, and can swing like a cradle around a shaft 43 fixed to the support frame 41A.

  The developing cartridge 42 includes a developing roller 42A, a supply roller 42B, a layer thickness regulating blade 42C, and a toner containing portion 42D. The support frame 41A has an opening on the upper side. In a state where the developing unit 40 is mounted on the main body case 2, the developing roller 42 </ b> A supported by the developing unit holder 41 </ b> B can come into contact with the photosensitive drum 32 at an oblique upper portion thereof. Each developing cartridge 42 has the same configuration except for the color of the toner stored in the toner storage portion 42D.

  As shown in FIG. 1, the transfer unit 50 is provided between the photosensitive unit 30 and the paper discharge tray 2B, and includes an intermediate transfer belt 51, four primary transfer rollers 52, a secondary transfer roller 53, and a drive roller 54. The driven roller 55 and the cleaning unit 56 are mainly provided.

  The driving roller 54 and the driven roller 55 are spaced apart in parallel in the front-rear direction, and an intermediate transfer belt 51 composed of an endless belt is stretched therebetween. The respective photosensitive drums 32 are opposed to and in contact with the lower side of the outer peripheral surface of the intermediate transfer belt 51, and the secondary transfer roller 53 is opposed to and in contact with the rear side.

  Each primary transfer roller 52 is in contact with the inner peripheral surface of the portion of the intermediate transfer belt 51 that is stretched on the lower side, and each photoconductor so as to sandwich the intermediate transfer belt 51 between each photoconductor drum 32. It is arranged opposite to the drum 32. The secondary transfer roller 53 is disposed to face the drive roller 54 so as to sandwich the intermediate transfer belt 51. The secondary transfer roller 53 is provided on the rear cover 2C. A transfer bias is applied to the primary transfer roller 52 and the secondary transfer roller 53 by constant current control during transfer.

  The cleaning unit 56 is disposed on the upper front side of the intermediate transfer belt 51, removes the toner remaining on the intermediate transfer belt 51 by the cleaning roller 57, and removes it to the toner storage unit 58 disposed on the rear side of the cleaning roller 57. The toner is stored.

  The fixing unit 60 is provided on the upper rear side of the intermediate transfer belt 51 and mainly includes a heating roller 61 and a pressure roller 62 that is disposed to face the heating roller 61 and presses the heating roller 61.

  In the image forming unit 5 configured as described above, first, the surface of each photosensitive drum 32 is uniformly charged by each scorotron charger 33 and then exposed by the laser light emitted from the exposure device 7. The As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed on each photosensitive drum 32. In addition, the toner in the toner container 42D is supplied to the developing roller 42A by the rotation of the supply roller 42B, and enters between the developing roller 42A and the layer thickness regulating blade 42C by the rotation of the developing roller 42A, and has a constant thickness. A thin layer is carried on the developing roller 42A.

The toner carried on the developing roller 42A is supplied to the electrostatic latent image formed on the photosensitive drum 32 when the developing roller 42A comes into contact with the photosensitive drum 32. As a result, the toner is selectively carried on the photosensitive drum 32, the electrostatic latent image is visualized, and a toner image is formed. The toner images of the respective colors formed on the respective photosensitive drums 32 are sequentially superimposed and transferred onto the intermediate transfer belt 51 by the action of the respective primary transfer rollers 52 to which a transfer bias is applied.

  The toner image transferred to the intermediate transfer belt 51 is subjected to secondary transfer to which a transfer bias is applied when the paper P supplied to the image forming unit 5 passes between the intermediate transfer belt 51 and the secondary transfer roller 53. The image is transferred onto the paper P by the action of the roller 53. The sheet P onto which the toner image has been transferred is conveyed to the fixing unit 60 and passes between the heating roller 61 and the pressure roller 62 so that the toner image is thermally fixed. The paper P on which the toner image has been thermally fixed is discharged out of the main body case 2 by the paper discharge roller 6 and accumulated in the paper discharge tray 2B.

  Next, a detailed configuration relating to the attachment / detachment of the photosensitive unit 30 and the developing unit 40 will be described with reference to FIGS. As shown in FIG. 2B, among the walls of the support frame 41A, four walls 41C are formed in the wall in the rotation axis direction of the developing roller 42A, and the developing device holder 41B is connected to the support frame 41A. Each of the operation portions 41D protrudes outward from the hole 41C. The hole 41C has a vertically long shape that can move the operation portion 41D in the vertical direction. As shown in FIG. 2A, the color multifunction device 1 further includes a first operation bar 80, a second operation bar 90, a second operation bar driving member 100, and a lock member 110.

  The first operation bar 80 includes a bar body 81 supported so as to be movable in the arrangement direction of the four developing rollers 42A with respect to the support frame 41A, and an inclined member 82 engageable with the four operation portions 41D. Yes. The bar body 81 is a member that extends back and forth on the left and right sides of the support frame 41A. The bar main bodies 81 on both sides of the support frame 41A are connected on the front side of the support frame 41A, and can move integrally in the front-rear direction. The inclined member 82 has an inclined surface whose upper surface is lowered from the front side toward the rear side. The front half of the inclined surface is composed of a tilting member 82A that can tilt up and down about the rear end. The tilting member 82A is urged from below to above by a spring 82B.

  The second operation bar 90 is provided in the main body case 2 and is indicated by a virtual line in FIG. The second operation bar 90 includes four concave portions 91 that form steps that can be engaged with the four operation portions 41D, and one concave portion 92 that forms a step that can be engaged with the frontmost operation portion 41D. I have. The interval between the four concave portions 91 is the same as the interval between the four operation portions 41D.

  The second operation bar drive member 100 meshes with the rear end portion of the second operation bar 90, and rotates according to the control of a control unit (not shown) to slide the second operation bar 90 back and forth. .

  In addition, about the hole 41C, the operation part 41D, the inclined member 82, the second operation bar 90, etc., only the left side surface (front side of the paper surface) is illustrated, but these are also the same on the right side surface (back side of the paper surface). Is provided.

  The lock member 110 is provided on the rear side of the support frame 41 </ b> A of the developing unit 40, and supports the rod-shaped member 111, the flange portion 112 formed at the lower end portion of the rod-shaped member 111, and the upper end portion of the rod-shaped member 111. A spring 113 that biases in a direction away from the frame 41A, and a holding member 114 that holds the upper end portion of the rod-like member 111 and prevents the dropping from the support frame 41A are provided. The collar portion 112 of the lock member 110 is provided in the main body case 2 by the claw protruding downward in a state where the developing unit 40 is completely accommodated in the main body case 2 and the first operation bar 80 is pushed backward. It is engaged with the lock engaging portion 2D (see FIG. 4D).

  As shown in FIGS. 2A and 4C, the photosensitive unit 30 engages with the rotation shaft of the developing roller 42A to guide the movement of the developing roller 42A and to the photosensitive drum 32. A groove 34 is provided for positioning the developing roller 42A.

<Color development position>
As shown in FIGS. 2A and 2B, the operation portion 41D is placed on the tilt member 82A of the tilt member 82, the tilt member 82A is urged upward by the spring 82B, and the operation portion 41D is further moved to the second position. When engaged with the recess 91 of the operation bar 90, as shown in FIG. 2C, the four developing rollers 42A are in the developing positions where they abut against the four photosensitive drums 32 (color developing position). In a state where the four developing rollers 42 </ b> A are arranged at the color developing position, the color multifunction peripheral 1 can perform color development using the four photosensitive drums 32. At this color developing position, the developing roller 42A partially overlaps the photosensitive drum 32 when viewed from the direction in which the developing unit 40 is pulled out.

<Intermediate position>
When the second operation bar 90 is moved backward from the color development position shown in FIG. 2 by the second operation bar driving member 100 as shown in FIGS. 3A and 3B, the operation unit 41D and the second operation bar 41 The engagement of the operation bar 90 with the recess 91 is released. In this state, as shown in FIG. 3C, the four developing rollers 42A are slightly separated from the corresponding photosensitive drums 32 (intermediate position). In a state where the four developing rollers 42A are disposed at the intermediate position, the color multifunction peripheral 1 can clean the four photosensitive drums 32 by the cleaning unit 56, for example.

<Removal position>
When the user pulls the first operation bar 80 forward as shown in FIGS. 4A and 4B from the color development position shown in FIG. 2, the operation unit 41D and the inclined member 82 of the first operation bar 80 Is disengaged. In this state, as shown in FIG. 4C, the four developing rollers 42A are separated from the corresponding photosensitive drums 32 and are completely accommodated in the support frame 41A. That is, when viewed from the drawing direction of the developing unit 40, the developing roller 42A moves to a position where it does not overlap the photosensitive drum 32 (attachment / detachment position). In the present embodiment, a locking release member 83 protruding downward from the bar body 81 is provided at the rear end of the bar body 81 of the first operation bar 80. When the user pulls the first operation bar 80 forward, the unlocking member 83 engages with the upper end portion of the rod-shaped member 111, and the rod-shaped member 111 rotates. Thereby, the collar part 112 moves upward and the engagement with the main body case 2 is released. In a state where the four developing rollers 42 </ b> A are arranged at the attachment / detachment positions, the color multifunction peripheral 1 can pull out at least one of the photosensitive unit 30 and the developing unit 40 from the main body case 2.

  In the present embodiment, a pair of guide portions 44 and 45 extending in the front-rear direction and a wheel 46 positioned at the rear end are provided on the outer wall surface in the rotation axis direction of the developing roller 42A of the support frame 41A. The main body case 2 includes a guide portion 121 along the guide portion 45, a stopper portion 122 that is provided at the rear end portion of the guide portion 121 and restricts the rearward movement of the wheel 46, and a front end portion. Positioned wheels 123 are provided. When the user pulls the first operation bar 80, the wheel 123 rotates and the guide portion 44 moves on the wheel 123 and is sent to the front side, and the wheel 46 rolls on the guide portion 121, thereby developing unit. 40 is pulled out from the main body case 2.

<Monochrome development position>
When the second operation bar 90 is moved forward by the second operation bar driving member 100 from the color development position shown in FIG. 2 as shown in FIGS. The engagement of the operation bar 90 with the concave portion 91 is released, and only the foremost operation portion 41D is engaged with the concave portion 92. In this state, as shown in FIG. 5C, the development roller 42A on the front side is at the development position where it abuts on the photosensitive drum 32, and the remaining three development rollers 42A are slightly from the corresponding photosensitive drum 32, respectively. (Monochrome development position). In a state where the four developing rollers 42 </ b> A are arranged at the monochrome development position, the color multifunction peripheral 1 can perform monochrome development using the front photosensitive drum 32.

  Next, the drawing operation of the photosensitive unit 30 and the developing unit 40 will be described with reference to FIGS. FIG. 6 is a diagram for explaining a state in which the paper discharge tray is opened. FIG. 7 is a diagram for explaining a state in which the photosensitive unit is pulled out. FIG. 8 is a diagram for explaining a state in which the developing unit is pulled out.

  First, from the state shown in FIG. 1, the user opens the paper discharge tray 2B upward as shown in FIG. Subsequently, the user opens the front cover 2 </ b> A and pulls the first operation bar 80 to move the developing roller 42 </ b> A to the attachment / detachment position (see FIG. 4) and unlock the hook 112. As a result, the photosensitive unit 30 and the developing unit 40 can be pulled out.

  Here, as shown in FIG. 7, when the user grips and pulls the handle 35 provided on the front wall surface of the support frame 31, the wheel 36 provided on the rear side of the support frame 31 is attached to the main body case 2. The photoreceptor unit 30 is pulled out from the main body case 2 by moving up from the provided wheel mounting portion 124 onto the guide portion 125 and rolling. In this state, the user can replace the photosensitive drum 32.

  On the other hand, when the user pulls the first operation bar 80 forward as shown in FIG. 8 from the attached / detached state shown in FIG. 4, the developer unit 40 is pulled out from the main body case 2. In this state, the user can exchange the developing cartridge 42 accommodated in the developing device holder 41B.

According to the above, the following effects can be obtained in the present embodiment.
When the developer unit 40 is attached to or detached from the main body case 2, the plurality of developer cartridges 42 may be moved to the attachment / detachment position with respect to the support member 41 and the developer unit 40 may be pulled out. This eliminates the need for a large-scale mechanism that separates the developing cartridge 42 from the photosensitive drum 32 while supporting the weight of the entire developing unit 40, so that the developing unit 40 can be detached from the main body case 2 with a simple mechanism. Will be able to. Further, since only the developing unit 40 needs to be pulled out when the developing cartridge 42 is replaced, the main body case 2 can be prevented from falling.

  Further, since the position of the developing cartridge 42 can be changed by the operation portion 41D protruding from the hole 41C formed in the side wall of the support frame 41A, the position of the developing cartridge 42 can be easily changed. By providing the operation portion 41D in the cradle-shaped developer holder 41B that is not removed from the support frame 41A, it is not necessary to open the hole 41C to the upper edge of the support frame 41A. Can be kept high.

  Further, since the position of the developing cartridge 42 can be set at an intermediate position slightly separated from the photosensitive drum 32, the photosensitive drum 32 and the intermediate transfer belt 51 can be cleaned with a small amount of movement.

Further, the position of the plurality of developing cartridges 42 is a color developing position in which all of the plurality of developing cartridges 42 are in the developing position, and one of the plurality of developing cartridges 42 is in the developing position.
Since the remainder can be switched to a monochrome development position that is located away from the photosensitive drum 32, monochrome printing can be performed even when the color toner is used up.

  In addition, since the groove 34 that engages the developing cartridge 42 is provided in the photosensitive unit 30, the positioning of the developing cartridge 42 with respect to the photosensitive drum 32 is easy.

Further, since the plurality of developing cartridges 42 can be moved to the color developing position and the attaching / detaching position by operating the first operation bar 80, the operation is easy.
Further, since the first operation bar 80 is provided on the support frame 41A, the first operation bar 80 does not interfere with the operation unit 41D when the developing unit 40 is pulled out.

Further, since the plurality of developing cartridges 42 can be moved to the color developing position, the attaching / detaching position, and the intermediate position by operating the first operating bar 80 and the second operating bar 90, the operation is easy. Since the first operation bar 80 and the second operation bar 90 are provided on the side of the developing unit 40, the first operating bar 80 and the second operating bar 90 do not interfere with the attachment / detachment of the developing unit 40.
Further, since both ends of the developing roller 42A are positioned by the groove 34 provided in the photosensitive unit 30, the parallelism of the shafts of the photosensitive drum 32 and the developing roller 42A can be reliably obtained.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the above-described embodiment, the developing device holder 41B that supports the developing cartridge 42 is illustrated as being rotatable with respect to the support frame 41A. However, the present invention is not limited to this. That is, the developing unit of the present invention may be configured to slide the developing unit having the developing roller with respect to the support member.

  In the above-described embodiment, the color multifunction peripheral 1 is illustrated as an example of the image forming apparatus, but the present invention is not limited to this. That is, the present invention can be applied to a color printer that does not include a color copying machine or an image reading device (flatbed scanner).

  In the above-described embodiment, the exposure apparatus 7 using a laser as a light source has been exemplified. However, the present invention is not limited to this. That is, the light source of the light emitting element may be an LED, an EL (electroluminescence) element, a phosphor, or the like.

  In the above-described embodiment, the configuration in which the photosensitive unit 30 and the developing unit 40 are pulled out in the front-rear direction from the front side of the main body case 2 has been described. The structure pulled out from the side surface of case 2 (apparatus main body) may be sufficient.

  In the above-described embodiment, an example in which the developing roller 42A is in contact with the photosensitive drum 32 at the developing position is shown. However, as long as development on the photosensitive drum 32 is possible, the developing roller 42A is at the developing position. However, it may be in a separated state. That is, the phrase “the developing roller is close to the photosensitive drum” in this specification includes the case where the developing roller is in contact with the photosensitive drum and the case where the developing roller is not in contact with the photosensitive drum.

In the above-described embodiment, the recesses 91 and 92 that can be engaged with the operation unit 41D are formed in the second operation bar 90, and the operation unit 41D and the recesses 91 and 92 are engaged by the movement of the second operation bar 90. Thus, the developing roller 42A and the photosensitive drum 32 are close to each other, and the operation portion 41D and the concave portions 91 and 92 are disposed.
Although the configuration in which the developing roller 42A and the photosensitive drum 32 are separated by releasing the engagement is shown, the present invention is not limited to this. For example, a convex portion (step) is formed on the lower surface of the second operation bar, and the development roller is separated from the photosensitive drum by the operation portion being pushed down by the movement of the second operation bar, so that the operation portion is convex. The developing roller may be close to the photosensitive drum by being separated from the portion. Here, “close” is not limited to a state in which the photosensitive drum and the developing roller are in contact with each other, but is not in contact, but a state in which the photosensitive drum and the developing roller are closer than a separated state. Shall be included.

1 is a cross-sectional view illustrating a schematic configuration of a color multifunction peripheral as an example of an image forming apparatus. 4A and 4B are diagrams for explaining a color developing position of the developing unit, where FIG. 5A is a diagram illustrating an external structure of the photosensitive unit and the developing unit, FIG. 5B is a partially enlarged view of FIG. It is a figure which shows the internal structure of a photoreceptor unit and a developing device unit. 2A and 2B are diagrams for explaining an intermediate position of the developing unit, in which FIG. 3A is a diagram illustrating an external structure of the photosensitive unit and the developing unit, FIG. 2B is a partially enlarged view of FIG. FIG. 3 is a diagram illustrating an internal structure of a body unit and a developing unit. 4A and 4B are diagrams for explaining a mounting / demounting position of the developing unit, in which FIG. 4A is a diagram illustrating an external structure of the photosensitive unit and the developing unit, FIG. 5B is a partially enlarged view of FIG. FIG. 6 is a diagram showing an internal structure of the body unit and the developing device unit, and FIG. 4A and 4B are diagrams for explaining a monochrome development position of the developing unit, where FIG. 5A is a diagram illustrating an external structure of the photosensitive unit and the developing unit, FIG. 5B is a partially enlarged view of FIG. It is a figure which shows the internal structure of a photoreceptor unit and a developing device unit. It is a figure for demonstrating the state which opened the paper discharge tray. FIG. 6 is a diagram for explaining a state in which the photosensitive unit is pulled out. FIG. 10 is a diagram for explaining a state in which the developing unit is pulled out.

DESCRIPTION OF SYMBOLS 1 Color compound machine 2 Main body case 5 Image forming part 30 Photosensitive unit 32 Photosensitive drum 34 Groove part 40 Developing unit 41 Supporting member 41A Supporting frame 41B Developing unit holder 41C Hole 41D Operation part 42 Developing cartridge 42A Developing roller 50 Transfer unit 60 Fixing unit 80 First operation bar 81 Bar body 82 Inclining member 82A Inclining member 82B Spring 90 Second operation bar 91 Concave portion 92 Concave portion 100 Second operating bar driving member

Claims (5)

A photoreceptor unit having a plurality of photoreceptor drums;
A plurality of developing units provided corresponding to the plurality of photosensitive drums and having developing rollers; and a support member for supporting the plurality of developing units; an arrangement direction of the plurality of photosensitive drums from the apparatus main body A developer unit that can be pulled out
The plurality of developing units may include a developing position in the support member where the developing roller is close to the photosensitive drum, and the developing roller is further away from the photosensitive drum than the developing position. It is supported so as to be movable between the drawing position where it can be drawn with respect to the device body,
The plurality of developing devices are configured to be stopped and supported at an intermediate position between the developing position and the drawing position;
The photosensitive unit engages with the developing unit , guides the movement of the developing unit between the developing position and the intermediate position, and has a groove for positioning the position of the developing unit with respect to the photosensitive drum. Formed,
2. An image forming apparatus according to claim 1, wherein the developing unit is configured to be disengaged from the groove portion at a drawing position of the developing unit. The support member includes a support frame, and a developer holder that is supported movably with respect to the support frame and to which the developer is mounted.
The support frame has a hole formed in a wall in a rotation axis direction of the developing roller,
The image forming apparatus according to claim 1, wherein the developing device holder includes an operation unit that protrudes outward from the hole of the support frame.   The plurality of developing units correspond to a first state in which all of the plurality of developing units are in the developing position, and one of the plurality of developing units is in the developing position, and the rest of the plurality of developing units corresponds. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to be switchable between the second state at the intermediate position. A first operation bar including an inclined member that is supported so as to be movable in an arrangement direction of the plurality of developing rollers with respect to the support frame and has an inclined surface that can be engaged with the operation unit;
3. The apparatus according to claim 2, wherein by moving the first operation bar, the inclined surface presses the operation unit and the developing device can be moved between the developing position and the drawing position. The image forming apparatus described. A first operation bar provided with an inclined member having an inclined surface that is supported so as to be movable in the arrangement direction of the plurality of developing rollers with respect to the support frame and that can be engaged with the operation unit;
A level difference that is supported so as to be movable in the arrangement direction of the plurality of developing rollers with respect to the apparatus main body and engages with the operation unit to move the operation unit in a direction to approach or separate from the photosensitive drum. A second operation bar provided with;
A second operation bar drive member that moves the operation unit by moving the second operation bar to engage the operation unit and the step;
The inclined member is configured to be movable in a direction approaching / separating from the operation unit, and has a spring that biases the inclined surface toward the operation unit,
By moving the first operation bar, the inclined surface presses the operation unit, so that the developing unit can be moved between the development position and the drawing position, and the operation unit and the step are The image forming apparatus according to claim 1, wherein the developing unit is movable between the developing position and the intermediate position by being engaged.

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