JP5088573B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus applied to a recording apparatus, a display apparatus, and the like to which an electrophotographic system such as a copying machine, a FAX, and a printer is applied.

  In an electrophotographic image forming apparatus, an image carrier such as a photosensitive drum, a charging device for uniformly charging the image carrier, and a surface charge are converted into an electrostatic latent image for process execution. For exposing the electrostatic latent image to a visible image with a developer (hereinafter referred to as toner), and electrically transferring the visible image on the image carrier to a medium such as a recording material. A transfer device for mechanical transfer, a cleaning device for removing toner remaining in the transfer operation by the transfer device on the image carrier, and the visualized toner on the recording material by heat or pressure permanently. And a fixing device for fixing.

  Of these, the configuration including the image carrier, the charging device, the exposure device, the developing device, the transfer device, and the cleaning device is referred to as a “process unit”. There is no need, and an image forming apparatus using a process unit in which an image carrier, a charging device, a cleaning device, and a developing device are integrated is common.

  Each device in each process has been promoted to reduce the size and speed of the device, especially with the increase in full-color output, and further demanded longer life, higher reliability, higher image quality and lower price. Yes.

  As a developing device, generally, a so-called two-component developing method using a mixture of toner and carrier is mainstream, and it is possible to output an image for a long time by continuously supplying the toner.

  However, such a two-component development method has a problem that the carrier deteriorates with time.

  Therefore, in recent years, mainly from the viewpoint of prolonging the service life and reliability, it has deteriorated over time by replenishing carrier materials in addition to toner and discharging excess carrier materials in a timely manner. An increasing number of image forming apparatuses are equipped with a “trickle-type” developing device that can suppress deterioration by replacing a carrier material with a certain probability.

  As described above, the two-component development method can achieve a long life and high reliability by adopting the “trickle method”. However, at present, technical countermeasures do not progress so much, and therefore, it is not possible to expect a long life for the image carrier, the charging device, and the cleaning device.

  Accordingly, when the image carrier, the charging device, and the cleaning device are integrated as a drum cartridge and the trickle method is adopted, the time required for replacement can be reduced by integrating the drum cartridge and the developing device. Since the lifespan of the drum cartridge and the developing device is different, it is wasteful of resources to replace both of them together. For this reason, it is necessary to separate the drum cartridge and the developing device from each other. That is, when the drum cartridge and the developing device are configured separately, it is desirable that the drum cartridge and the developing device can be easily replaced.

  For this reason, conventionally, for example, a technique has been proposed in which a process unit with a short lifetime is arranged at a position where it can be replaced with priority (see, for example, Patent Document 1).

Further, a technique has been proposed in which the drum cartridge and the developing device are taken out of the apparatus in an integrated state and can be easily separated outside the apparatus (for example, see Patent Document 2).
JP-A-5-289428 JP 2003-114601 A

  However, in the technique of Patent Document 1, a process unit having a long life cannot be easily replaced.

  In the technique disclosed in Patent Document 2, when the drum cartridge and the developing device are taken out and separated, a working space for that purpose must be secured, and the separation between the two is simple only outside the machine. If the configuration is such that the drum cartridge and the developing device are separated and dropped during the replacement work outside the apparatus, they may be damaged.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus in which a developing device and a drum cartridge attached via a tray can be individually replaced by a simple operation.

  The above problem is solved by the following means.

[1] a drum cartridge;
A developing device;
A tray arranged to be drawable with respect to the main body of the apparatus,
One of the drum cartridge and the developing device is attached to the tray so as to be in a removal preventing state in which removal from the tray is prevented, and the one of the drum cartridge and the developing device is only in a position where the tray is pulled out by the first pulling amount. First attachment means for releasing the removal preventing state;
The other one of the drum cartridge and the developing device is attached to the tray so as to be in a removal prevention state in which removal of the drum cartridge and the developing device is prevented, and the tray has a second drawing amount different from the first drawing amount. Second attaching means for releasing the other removal preventing state only at the pulled-out position;
An image forming apparatus comprising:

  [2] The image forming apparatus according to [1], wherein the first attachment unit is configured not to release the removal prevention state of the one unless the other is removed from the tray.

  [3] The image forming apparatus according to [2], wherein the first pull-out amount is set smaller than the second pull-out amount.

  [4] The image forming apparatus according to [2] or [3], wherein the second attachment unit is configured to be attached to the tray via the one by attaching the other to the one. .

  According to the invention described in [1], the first pull-out amount of the tray from which the removal prevention state with respect to one tray of the drum cartridge and the developing device is released, and the first of the trays from which the other removal prevention state is released are released. Since the amount of pull-out 2 differs, it is possible to avoid a situation in which the drum cartridge and the developing device attached to the tray are removed at the same time. That is, since either the drum cartridge or the developing device attached to the tray is removed first, when the tray is set to the first pull-out amount or the second pull-out amount, the removal preventing state for the later removal is not released. For this reason, it is possible to remove only one from the tray while securely securing the one to be left later to the tray.

  According to the invention described in [2] above, if the other of the drum cartridge and the developing device is not removed from the tray, the removal preventing state of one is not released, so that the preset order of removing one after the other is set. On the other hand, the situation where these are removed can be avoided.

According to the invention described in [3] above, since the first pull-out amount is set smaller than the second pull-out amount, the tray is first pulled out to the second pull-out amount to remove the other, If the operation of returning the tray to the first pull-out amount is not performed, one side does not come off, so that it is possible to reduce the situation where one side is unintentionally removed after the other is removed first.

According to the invention described in [4] above, since the other is attached to the tray via one, the drum cartridge and the developing device are directly coupled to each other, and the positional relationship between the two can be maintained properly and stable. It can contribute to image formation.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a full-color electrophotographic image forming apparatus, and FIG. 2 is a schematic cross-sectional view showing a process unit used in the image forming apparatus.

  1 and 2, an image forming apparatus 20 includes an image carrier 1 such as a photosensitive drum, a charging device 2 for uniformly charging the surface of the image carrier 1 to form a potential, and a charging device. 2 to irradiate light to form a predetermined electrostatic latent image on the surface of the image carrier 1 charged to a desired potential by 2 and toner in the area where the electrostatic latent image is formed. A plurality of developing devices 4 for applying a mirror image by applying an electric field or the like are provided, and the powder on the image carrier 1 that has been mirrored is sequentially transferred onto a so-called transfer belt 5 called an intermediate transfer member. A primary transfer device 6 for moving by an electric field / pressure, a secondary transfer device 7 for moving powder on the transfer belt 5 onto a recording medium 11 such as recording paper by an electric field / pressure, and a recording medium 11 The powder that has moved up is permanently fixed by heat or pressure. And a because of the fixing device 8.

  On the other hand, in the primary transfer device 6, the powder may not completely move on the transfer belt 5 and may remain slightly on the image carrier 1. At this time, the residual powder remaining on the image carrier 1 is electrically and mechanically removed from the image carrier 1 by the cleaning device 9, and then the image carrier 1 is applied to the image carrier 1 by the slow current device 12. The charging process is performed again.

  In addition, since the mirror image formed on the transfer belt 5 cannot be completely transferred onto the recording medium in the secondary transfer device 7, it remains as a slight residual powder on the transfer belt 5. In some cases, this is electrically and mechanically removed by the transfer belt cleaning device 10.

  In order to form a color image, for example, a plurality of image forming units for each color such as yellow (Y), magenta (M), cyan (C), and black (K) are used and arranged as shown in FIG. In some cases, one image forming apparatus unit may be provided alone to form only a monochrome image.

  FIG. 3 is an external perspective view showing a process unit unit including the drum cartridge 21 and the developing device 30.

  In FIG. 3, the process unit section includes a tray 34, a drum cartridge 21 including the image carrier 1 accommodated via the tray 34, a developing device 30 including the developing device 4, and the drum cartridge 21 and the developing device. And a tray 34 to which 4 is attached.

  In this embodiment, the drum cartridge 21 is configured as a unit including the image carrier 1, the charging device (FIGS. 1 and 2), and the concept of the drum cartridge 21 in the present invention is at least an image. What is necessary is just to provide the support body 1. FIG.

In this embodiment, the developing device 30 includes the developing device 4 having the developing roller 31, a toner supply unit (not shown), and the like. However, the concept of the developing device in the present invention is at least the developing roller 31. As long as it has.

On the inner surface of the side wall of the apparatus main body 20A in the image forming apparatus 20, a movable member 200 that is movable in the front-rear direction with respect to the apparatus main body 20A is held. A tray sliding rail is fixed to the inner surface of the movable member 200 along the longitudinal direction (front-rear direction).

  A slider rail 341 that is fitted to the tray sliding rail is fixed to the outer surface of the side wall of the tray 34, and the tray 34 is set to be movable in the front-rear direction along the rail via the slider rail 341. ing. Thereby, the tray 34 can be pulled out from the apparatus main body 20A.

  In addition, the image forming apparatus 20 includes a first attachment unit that attaches one of the drum cartridge 21 and the developing device 30 to the tray 34, and a second attachment unit that attaches the other drum cartridge 21 to the tray 34. And.

  The first attachment means attaches the developing device 30 to the tray 34 such that the developing device 30 is prevented from being removed from the tray 34. The first attachment means releases the developing device 30 from the removal preventing state and allows the tray 34 to be removed from the tray 34 at a position where the tray 34 is pulled out by a predetermined first pull-out amount described later. It is configured as follows.

  In this embodiment, the first attachment means is configured to be prevented from being removed from the tray 34 by restricting the developing device 30 from being lifted upward. 20 on the left side of the front face, a first lifting restricting portion 50 that restricts lifting of the developing device 30 above the tray 34, and the developing device 30 on the opposite side of the developing device 30, in this embodiment, on the right side. 34, and a second lifting restricting portion 40 that restricts the lifting from 34.

  The first lifting restricting portion 50 restricts the left side of the developing device 30 from being lifted upward. For example, the first lifting restricting portion 50 is an inverted L shape fixed to the apparatus main body 20A side (specifically, the movable member 200). A fixing member 32 and a protruding member 33 provided on the lower surface side of the developing device 30 are provided.

  As shown in FIGS. 3 and 5, the inverted L-shaped fixing member 32 protrudes rightward so as to face the upper surface of the left end of the developing device 30, and interferes with the upper surface of the developing device 30. Thus, the upward lifting of the developing device 30 is restricted.

  When the developing device 30 is attached to the tray 34 as shown in FIG. 3, the protruding member 33 enters the lower side of the slider rail 341 of the tray 34 and interferes with the slider rail 341 from the lower side. The upward lifting of the developing device 30 is restricted.

  The second lifting restricting portion 40 restricts the right side of the developing device 30 from being lifted upward. As shown in FIGS. 4 and 9, the second lifting restricting portion 40 is located at the front portion of the tray 34 and is located on the inner surface of the bottom wall. The engaging piece 402 is provided upright.

  When the developing device 30 is set at a predetermined position on the tray 34, the engaging piece 402 has upper and lower ribs 301, which protrude from the front side wall of the developing device 30, as shown in FIG. It is restricted that the developing device 30 is lifted by entering between 302.

  Among the elements constituting the first mounting means, the interference between the projection member 33 and the slider race 341 and the engagement between the engagement piece 402 and the ribs 301 and 302 cause the developing device 30 to move forward with respect to the tray 34. It is released by slightly pulling out.

  On the other hand, the inverted L-shaped fixing member 32 and the upper surface of the developing device 30 interfere only at a position where the tray 34 on which the developing device 30 is set is pulled out by a predetermined first pulling amount (state shown in FIG. 6). The state is canceled and the developing device 30 can be lifted.

  Specifically, a groove portion 51 is provided at the back of the upper surface of the developing device 30 so that the side wall surface is slightly folded, and the tray 34 on which the developing device 30 is set is attached to the inverted L-shaped fixing member 32 on the apparatus main body side 20A. The leading end portion 32a of the developing device 30 and the groove portion 51 on the developing device 30 side are pulled out to the pulling position (the state shown in FIG. 6), which is the first pulling amount, so that the removal preventing state of the developing device 30 can be released. ing.

  On the contrary, the first attachment means including the inverted L-shaped fixing member 32 maintains the removal preventing state of the developing device 30 except for the drawing position that is the first drawing amount.

  Further, the first attachment means is configured such that the drum cartridge 21 is positioned above the developing device 30 in a state where the drum cartridge 21 is attached to the tray 34, so that the drum cartridge 21 is connected to the apparatus main body 20 </ b> A. The interference prevents the developing device 30 from being removed from the tray 34, that is, the removal preventing state of the developing device 30 is not released.

  The second attachment means attaches the drum cartridge 21 to the tray 34 so that the drum cartridge 21 is prevented from being removed from the tray 34. The first attachment means can release the drum cartridge 21 from the tray 34 and remove it from the tray 34 at a position where the tray 34 is pulled out by a predetermined second pull-out amount described later. It is configured as follows.

  This second attachment means attaches the drum cartridge 21 to the tray 34, but in this embodiment, the drum cartridge 21 is attached to the developing device 30 previously attached to the tray 34. A joining portion 60 for joining 21 to the developing device 30 is provided. That is, in this embodiment, the drum cartridge 21 is attached to the tray 34 via the developing device 30.

  In this embodiment, the joint portion 60 has a pair of front and rear lever members 62 and 62 disposed at both ends in the longitudinal direction (front-rear direction) of the drum cartridge 21.

  As shown in FIG. 3, the lever members 62 and 62 are pivotally supported by a pivot 61 provided in the drum cartridge 21 so that the lever members 62 and 62 can swing in the left-right direction. Key-shaped engaging portions 62a and 62a are formed which enter the lower side of the developing roller shaft (not shown) and engage in a holding state.

  A spring force is applied to the pair of lever members 62, 62 in a direction to engage with the developing roller shaft by a spring (not shown).

  Each upper end portion 22 of the pair of lever members 62, 62 is configured as a release operation portion that releases the locking state of the locking portions 62a, 62a by a pushing operation against a spring force. By releasing the locking state of the portions 62a and 62a, the joined state of the drum cartridge 21 with respect to the developing device 30 is released.

  Further, the second attachment means has a removal preventing portion 80 that does not release the removal preventing state of the drum cartridge 21 unless it is at the drawing position of the predetermined second pulling amount.

  As shown in FIG. 8, the take-out prevention unit 80 includes, for example, an exterior part of the apparatus main body 20 </ b> A, and prevents the removal of the drum cartridge 21 by interfering with the upper surface side of the drum cartridge 21. ing.

  The removal prevention state by the removal prevention unit 80 is canceled when interference between the removal prevention unit 80 and the drum cartridge 21 is eliminated at a position where the tray 34 on which the drum cartridge is set is pulled out to the outermost part. ing.

  That is, in this embodiment, the drawing position of the second pull-out amount is a position where the tray is pulled out to the outermost portion, and the above-described first pull-out amount pull-out position is a position where the tray is slightly pulled back from here. It is different from the position.

  Therefore, at the position of the first pull-out amount of the tray 34 (FIG. 5), the drum cartridge 21 cannot be taken out even if the joining of the drum cartridge 21 and the developing device 30 by the joining portion 60 can be released.

  Next, a procedure for attaching and detaching the drum cartridge 21 and the developing device 30 will be described.

  When the drum cartridge 21 or the developing device 30 is attached to the tray 34, first, the tray 34 is pulled out from the apparatus main body 20A side.

  The developing device 30 is moved rearward to cause the protruding member 33 to enter the lower side of the rail 341, and the developing device 30 is located below the distal end portion 32a of the inverted L-shaped fixing member 32 on the apparatus main body 20A side. As described above, when the pull-out position of the tray 34 is shifted rearward to a position corresponding to the first pull-out amount so that the tip end portion 32a is avoided by the groove portion 51 of the developing device 30, the developing device 30 is placed on the tray 34. It is set at a predetermined position.

  In this set state, the tip end portion 32a of the inverted L-shaped fixing member 32 faces the upper surface of the left end portion of the developing device 30, and the protruding member 33 enters the lower side of the rail 341. The engaging piece 402 on the tray 34 enters between the pair of upper and lower ribs 301 and 302 of the developing device 30. As a result, the developing device 30 is set on the tray 34.

  If the drawing position of the tray 34 is moved from the position corresponding to the first drawing amount, the developing device 30 is in a removal prevention state.

  With the developing device 30 set on the tray 34, the tray 34 is pulled out to the position of the total drawing amount (second drawing amount position) shown in FIG. 5, and then the drum cartridge 21 is developed from the posture shown in FIG. If installed on the apparatus 30, the hook-shaped locking pieces 62 a of the pair of front and rear lever members 62, 62 in the joint portion 60 enter and engage the lower side of the developing roller shaft, so that the drum cartridge 21 is developed by the developing apparatus. 30. And if the tray 34 is pushed in and accommodated in the apparatus main body 20A side, it can be used.

  When the drum cartridge 21 or the developing device 30 is replaced, the tray 34 stored on the apparatus main body 20 side is pulled out.

  When the tray 34 is pulled out to the position of the full pulling amount shown in FIG. 5 and then the upper end portions 22 of the pair of lever members 62 and 62 in the joint portion 60 are pushed in, the lower end portions of the lever members 62 and 62 are operated. Since the hook-shaped locking piece 62a is detached from the developing roller shaft, the joined state between the drum cartridge 21 and the developing device 30 is released.

  At this time, as shown in FIG. 8, since the entire drum cartridge 21 protrudes outside the apparatus main body 20A, the removal preventing state is released without interfering with the removal preventing portion 80.

  For this reason, first, the drum cartridge 21 can be pulled up and removed from the tray 34 to be replaced.

  Although the drum cartridge 21 can be taken out at the position where the tray 34 is fully pulled out, the tip 32a of the inverted L-shaped fixing member 32 is developed with respect to the developing device 30 as shown in FIG. Further, the protrusion member 33 of the developing device 30 enters the lower side of the rail 341, and the engaging piece 402 of the tray 34 is located at the front portion of the developing device 30. Since the ribs 301 and 302 are engaged, the developing device 30 cannot be removed even if the joining with the drum cartridge 21 is released.

  Therefore, if the tray 34 is pushed back slightly from the position of the total amount of drawer (second drawer amount) and set to the position of the first drawer amount shown in FIG. On the other hand, as shown in FIG. 6, the groove 51 of the developing device 30 is in a state of being opposed at the same position. That is, the developing device 30 can be avoided from the tip end portion 32a of the inverted L-shaped fixing member 32, and the removal preventing state is released.

  As a result, the front end portion 32a of the solid member 32 is avoided through the groove portion 51 while slightly lifting the rear side of the developing device 30 as shown in FIG. When the developing device 30 is moved forward (front side) with respect to the tray 34, the projecting member 33 escapes from the lower side of the rail 341, while the engaging piece 402 has the ribs 301 and 302 of the developing device 30. Escape from.

  Therefore, if the drum cartridge 21 has been removed first at the position of the total drawing amount of the tray 34, the developing device 30 can be easily taken out from the tray 34 and replaced at the position of the first drawing amount of the tray 34. it can.

  In this example, the take-out prevention unit 50 has been described with an example in which the tray 34 is held so as to be in a removal prevention state via the inverted L-shaped fixing member 32, the protruding member 33, and the engagement piece 402. It is not limited to the structure which employ | adopts these members.

  Further, in this example, the groove 51 that functions as the take-out prevention release unit is configured by the vertical groove provided in the developing device 30, but other configurations may be adopted.

  Although the developing device 30 cannot be removed even when the drum cartridge 21 is taken out at the position where the tray 34 is fully pulled out, the user accidentally lifts and removes the rear side of the developing device 30 at the position where the total amount is pulled out. If it does so, there exists a possibility that the site | part top surface of this developing device 30 may hit the front-end | tip part 32a of the reverse L-shaped fixing member 32, and the site | part may be damaged. For this reason, as shown in FIG. 10, it is preferable to ensure the strength by projecting the rear measuring end portion 30b of the developing device 30 by a minute amount (t) from the side surface.

  On the other hand, when the tray 34 is pushed back to the position of the first pull-out amount with the drum cartridge 21 being joined to the developing device 30, the exterior of the apparatus main body 20 </ b> A that is the second removal prevention unit with respect to the drum cartridge 21. Since the portion 80 protrudes relatively above the drum cartridge 21, the drum cartridge 21 cannot be removed even if the joint with the developing device 30 is released.

  Of course, the second take-out prevention unit 80 is not limited to a configuration using the projecting exterior portion of the apparatus main body 20A.

  As described above, according to the above-described embodiment, the first pull-out amount of the tray 34 from which the removal preventing state of the developing device 30 with respect to the tray 34 is released, and the tray from which the removal prevention state of the drum cover ridge 21 is released. Since the second pull-out amount of 34 is different, it is possible to avoid a situation in which the drum cartridge 21 and the developing device 30 attached to the tray 34 are removed at the same time. That is, in order to remove the drum cartridge 21 attached to the tray 34, when the tray 34 is pulled out to the position of the second pull-out amount, the removal preventing state of the developing device 30 is not released because it is not at the position of the first pull-out amount. Therefore, only the drum cartridge 21 can be removed from the tray 34 while the developing device 30 is securely fastened to the tray 34.

  Further, if the drum cartridge 21 is not removed from the tray 34, the removal preventing state of the developing device 34 is not released. Therefore, these are removed in the preset order of removing the developing device 30 after the drum cartridge 21. Can be avoided.

  Further, since the first pull-out amount is set smaller than the second pull-out amount, the tray 34 is pulled out to the second pull-out amount to remove the drum cartridge 21, and then the tray 34 is set to the first pull-out amount. Since the developing device 30 is not detached unless the operation of returning to the uppermost position is performed, it is possible to reduce the situation where the developing device 30 is unintentionally detached after the drum cartridge 21 is removed first.

  In addition, since the drum cartridge 21 is attached to the tray 34 via the developing device 30, the drum cartridge 21 and the developing device 30 are directly coupled to each other, so that the positional relationship between the two can be maintained properly and stable image formation can be achieved. Can contribute.

  In this embodiment, the position of the second pull-out amount of the tray 34 is set as the position of the total pull-out amount of the tray 34, and the position of the first pull-out amount of the tray 34 is changed from the position of the total pull-out amount of the tray 34. Although described as a position where it is pushed back a little, the positions of the first and second withdrawal amounts are not limited to those of the configuration of this example.

  In the above-described embodiment, the configuration in which the developing device 30 is first attached to the tray 34 and then the drum cartridge 21 is attached has been described. However, the present invention is directed to the developing device 30 and the drum on the tray 34. The mounting order of the cartridges 21 may be reversed. That is, the drum cartridge 21 may be attached by the first attachment means, and the developing device 30 may be attached by the second attachment means.

  Further, the second mounting means is configured to mount the drum cartridge 21 on the tray 34 via the developing device 30 by mounting the drum cartridge 21 to the developing device 30, but the drum cartridge (the other of the two). 21 may be directly attached to the tray 34.

  Also, the specific configuration of the second mounting means has been described in the example realized by the joint portion 60 using the pair of lever members 62, 62 having the engagement piece 62a. It is also possible to join them together.

1 is a schematic cross-sectional view showing a full-color electrophotographic image forming apparatus according to an embodiment of the present invention. It is a schematic sectional drawing which similarly shows the process unit in an image forming apparatus. FIG. 3 is an external perspective view showing a process unit unit including a drum cartridge and a developing device in the image forming apparatus. Similarly, it is the perspective view which looked at the developing device from the upper right. FIG. 6 is a plan view showing the drum cartridge and the developing device at the position of the second pull-out amount of the tray. FIG. 6 is a plan view showing the drum cartridge and the developing device at the position of the first pull-out amount of the tray. It is a perspective view which shows the removal operation state of a developing device. It is a top view which shows a drum cartridge in the taking-out prevention state at the position of the 1st drawer amount. FIG. 3 is a schematic front view showing a state in which the developing device is prevented from being detached by a regulating piece. It is explanatory drawing of the reinforcement part of a developing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Image forming apparatus 20A ... Apparatus main body 21 ... Drum cartridge (the other)
30 ... Developing device (one side)
34 ... Tray 40 ... Second lifting prevention portion (first mounting means)
50 ... 1st lifting prevention part (1st attachment means)
60 ... Joint portion (second mounting means)
80 ... Removal prevention part (second mounting means)

Claims (4)

A drum cartridge,
A developing device;
A tray arranged to be drawable with respect to the main body of the apparatus,
One of the drum cartridge and the developing device is attached to the tray so as to be in a removal preventing state in which removal from the tray is prevented, and the one of the drum cartridge and the developing device is only in a position where the tray is pulled out by the first pulling amount. First attachment means for releasing the removal preventing state;
The other one of the drum cartridge and the developing device is attached to the tray so as to be in a removal prevention state in which removal of the drum cartridge and the developing device is prevented, and the tray has a second drawing amount different from the first drawing amount. Second attaching means for releasing the other removal preventing state only at the pulled-out position;
An image forming apparatus comprising:   2. The image forming apparatus according to claim 1, wherein the first attachment unit is configured not to release the removal prevention state of the one unless the other is removed from the tray.   The image forming apparatus according to claim 2, wherein the first pull-out amount is set smaller than the second pull-out amount.   The image forming apparatus according to claim 2, wherein the second attachment unit is configured to be attached to the tray via the one by attaching the other to the one.

Images