Image forming apparatus

Abstract

To prevent wrong attachment of a process cartridge without impairing a reduction in size of an image forming apparatus.SOLUTION: An image forming apparatus comprises: process cartridges PY, PM, PC, PK that each have a photoconductor drum 11 and perform image formation on a recording material; an optical scanner 2 that irradiates the photoconductor drums 11 with laser beams to form electrostatic latent images; and a cartridge tray 40 that is movable between the outside of the image forming apparatus and an accommodation position. The optical scanner 2 has a housing 3, and a lid member 5 that covers an opening of the housing 3. The lid member 5 has wrong attachment prevention parts 6M, 6C, 6K that detect process cartridges attached to the cartridge tray 40 in a wrong way. The process cartridges PM, PC, PK have interference walls M2, C2, K2 that are brought into contact with the wrong attachment prevention parts 6M, 6C, 6K when the process cartridges are attached to the cartridge tray 40 in a wrong way.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to an image forming apparatus such as a copying machine or a printer.

Background Art

[0002] Conventionally, a color image forming apparatus for forming a color image irradiates laser light from a plurality of light sources of an optical scanning device onto a corresponding photosensitive drum respectively to form an electrostatic latent image, and superimposes toner images visualized by a plurality of toners to form a color image. Each process cartridge corresponding to a plurality of colors of toner has process means such as a photosensitive drum, charging means, developing means, etc. integrated therein, and is detachably disposed on the image forming apparatus main body.

[0003] For example, Patent Document 1 describes a configuration in which a tray for supporting a plurality of arranged process cartridges called an in-line method is provided inside the image forming apparatus. In the image forming apparatus described in Patent Document 1, the tray is pulled out of the image forming apparatus, and the process cartridge is replaced. Further, Patent Document 2 describes a configuration in which the process cartridge is detached from the image forming apparatus in the rotational axis direction of the photosensitive drum. In Patent Document 1, after replacing the necessary process cartridge among the plurality of process cartridges placed on the tray pulled out of the image forming apparatus, the tray is inserted into the image forming apparatus to replace the process cartridge. On the other hand, in the image forming apparatus described in Patent Document 2, only the process cartridge that needs to be replaced is pulled out, and a new process cartridge is mounted. Therefore, the process cartridges are replaced individually, and the attachment and detachment of the process cartridges that are not replaced are not performed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventional color image forming apparatuses have had the following problems. In a color image forming apparatus, a plurality of process cartridges are used to form a color image on a recording material. For example, in the image forming apparatus of Patent Document 1, the position of the process cartridge placed on the tray is determined, and if the replaced process cartridge is not mounted at the predetermined position of the tray, a desired image cannot be formed on the recording material. Although the replacement of the process cartridge is performed by the user, the image forming apparatus is not provided with a mechanism for preventing misloading even if the process cartridge is mounted at a position different from the predetermined position. Therefore, there is a problem that image formation is performed with the replaced process cartridge misloaded, resulting in image defects.

[0006] The present invention has been made under such circumstances, and an object thereof is to prevent misloading of a process cartridge without impairing the miniaturization of an image forming apparatus.

Means for Solving the Problems

[0007] In order to solve the above-described problems, the present invention has the following configuration.

[0008] (1) An image forming apparatus that forms an image on a recording material, comprising: a photosensitive drum; a plurality of image forming units that form an image on the recording material; a plurality of light sources; an optical scanning device that irradiates the photosensitive drum of the corresponding image forming unit with laser light emitted from the light sources to form an electrostatic latent image; a moving unit on which the plurality of image forming units are mounted at predetermined positions and which is movable between the outside of the image forming apparatus and a storage position where the laser light emitted from the optical scanning device is irradiated onto the photosensitive drum of the corresponding image forming unit. The optical scanning device includes a housing that houses the plurality of light sources and a lid portion that covers an opening of the housing. The lid portion faces the image forming unit mounted on the moving unit, protrudes toward each corresponding image forming unit side, and has a plurality of mismounting detection portions that detect an image forming unit mismounted on the moving unit. The plurality of image forming units have wall portions that contact the mismounting detection portions when mismounted on the moving unit. and a rib portion facing the lid portion; having and the wall portion is provided at positions of both ends of the rib portion in a direction orthogonal to the moving direction of the moving unit, and at positions where the misloading detection portion contacts when the moving unit is misloaded. Each misloading detection portion is provided at a position corresponding to the plurality of image forming portions when the moving unit on which the plurality of image forming portions are mounted is located at the storage position. When all the image forming portions are mounted at the predetermined position of the moving unit, they do not contact the wall portion provided on the corresponding image forming portion. An image forming apparatus characterized by the above. (2) An image forming apparatus that forms an image on a recording material, comprising: a plurality of image forming portions that have a photosensitive drum and form an image on the recording material; and an optical scanning apparatus that has a plurality of light sources and irradiates the photosensitive drum of the corresponding image forming portion with laser light emitted from the light sources to form an electrostatic latent image. The optical scanning apparatus includes a housing that houses the plurality of light sources, and a lid portion that covers an opening of the housing. The lid portion faces the image forming portion and has a plurality of protruding portions that protrude toward the corresponding image forming portion side and detect a misloaded image forming portion. Each image forming portion has a groove portion into which the protruding portion is inserted when mounted at the corresponding position of the optical scanning apparatus. The optical scanning apparatus is disposed above the lid portion in the vertical direction. The protruding portion and the groove portion are formed in the rotation axis direction of the photosensitive drum of the image forming portion. The position where the protruding portion is formed is different depending on the corresponding image forming portion. An image forming apparatus characterized by this.

Effect of the Invention

[0010] According to the present invention, it is possible to prevent the mismounting of a process cartridge without impairing the miniaturization of the image forming apparatus.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example

[0013] [Image Forming Apparatus] FIG. 1 is a schematic cross-sectional view showing the configuration of the image forming apparatus 1 according to Embodiment 1. The image forming apparatus 1 includes an optical scanning device 2 and process cartridges PY, PM, PC, and PK which are image forming units in the main body. The image forming apparatus 1 in this embodiment forms a full-color image by superimposing toner images visualized with four colors of toner: yellow (Y), magenta (M), cyan (C), and black (K). As shown in FIG. 1, the process cartridges PY, PM, PC, and PK have the same configuration, and the a, b, c, and d at the end of the reference numerals of the members of each process cartridge indicate that they are the members of the process cartridges PY, PM, PC, and PK, respectively. In the following description, the description of a, b, c, and d at the end of the reference numerals will be omitted unless referring to the members of a specific process cartridge.

[0014] Also, in Embodiment 1, the side where the door 41 (to be described later) of the image forming apparatus 1 is provided is defined as the "front" side of the image forming apparatus 1, and the side opposite to the door 41 is defined as the "rear" side of the image forming apparatus 1. Further, when looking from the "front" side to the "rear" side of the image forming apparatus 1, the right side is defined as "right", and the left side is defined as "left".

[0015] With reference to FIG. 1, the configuration and the image forming process of the image forming apparatus 1 will be described. The optical scanning device 2 is disposed above the process cartridges PY, PM, PC, and PK in the vertical direction, and irradiates the photosensitive drums 11, which are image carriers carrying the toner images of the process cartridges PY, PM, PC, and PK, with laser lights L1, L2, L3, and L4 corresponding to image data. The photosensitive drums 11 of each process cartridge are charged to a uniform potential by a charging roller 12 in advance, and an electrostatic latent image is formed on the surface of the photosensitive drum 11 by the charge escaping only from the portion irradiated with the laser light from the optical scanning device 2. The electrostatic latent image on the photosensitive drum 11 has toner attached thereto by a developing roller 13, and a toner image is formed. A primary transfer roller 22 is disposed at a position facing the photosensitive drum 11, and when a transfer voltage is applied to the primary transfer roller 22, the toner images on the respective photosensitive drums 11 are sequentially superimposed and transferred onto the intermediate transfer belt 21.

[0016] On one hand, the recording material S, which is a recording medium placed in the paper feed cassette 31 arranged on the lower side in the vertical direction of the intermediate transfer belt 21, is fed from the paper feed cassette 31 by the pickup roller 32 in synchronization with the image forming process of the above-described process cartridge. The recording material S fed from the paper feed cassette 31, which is the stacking part, is conveyed to the secondary transfer roller 33, and the four-color toner image transferred onto the intermediate transfer belt 21 is transferred to the recording material S by the secondary transfer roller 33. The recording material S onto which the toner image has been transferred is conveyed to the fixing device 34, and the toner image is fixed to the recording material S by being heated and pressurized in the fixing device 34. Thereafter, the recording material S that has passed through the fixing device 34 is discharged to the external discharge tray 37 by the discharge rollers 35 and 36.

[0017] [Optical Scanning Device] FIG. 2 is a schematic cross-sectional view showing the configuration of the optical scanning device 2 that is installed on the frames Ff and Fr of the image forming apparatus 1 and exposes the photosensitive drum 11, which is the photosensitive member shown in FIG. 1. The optical scanning device 2 deflects the laser beams L1, L2, L3, and L4 emitted from a plurality of semiconductor lasers (not shown), which are light sources, by the rotating polygon mirror 4 having the deflector 7, and irradiates the corresponding photosensitive drums 11a, 11b, 11c, and 11d through the optical member. The optical scanning device 2 includes a deflector 7 having a rotating polygon mirror 4, first imaging lenses 8a and 8b that are imaging members for laser light, second imaging lenses 9a to 9d, folding mirrors 10a to 10f that are reflecting members, and a housing (also referred to as an optical box) 3 in which these members are arranged. Further, in order to seal the housing 3, the optical scanning device 2 has a lid member 5 that closes (covers) the opening of the housing 3.

[0018] As shown in Fig. 2, the housing 3 is disposed on the upper side in the vertical direction within the image forming apparatus 1, and the lid member 5 is disposed on the lower side in the vertical direction. That is, the lid member 5 is disposed closer to the process cartridges PY, PM, PC, PK than the housing 3 and faces the process cartridges PY, PM, PC, PK. Further, in the deflector 7, a drive substrate 7a for rotationally driving the rotating polygon mirror 4 is fixed to the bottom surface of the housing 3, and the rotating polygon mirror 4 is disposed on the lower side in the vertical direction than the drive substrate 7a. Further, in order to reduce the height of the image forming apparatus 1, the space between the optical scanning device 2 and the process cartridges PY, PM, PC, PK is narrowed so that no other components can enter.

[0019] Next, the operation of the optical scanning device 2 will be described. Laser lights L1, L2, L3, L4 emitted from a plurality of semiconductor lasers (not shown) pass through a plurality of lenses (not shown), are incident on the rotating polygon mirror 4 while being inclined with respect to the scanning plane D, and are deflected (scanning deflection) by the rotating polygon mirror 4. The laser light L1 deflected by the rotating polygon mirror 4 passes through the first imaging lens 8a, and then the optical path is deflected by the folding mirror 10c corresponding to the process cartridge PY. Then, the laser light L1 passes through the second imaging lens 9a and the opening of the lid member 5, and scans the surface of the photosensitive drum 11a at a constant speed while forming a spot on the photosensitive drum 11a of the corresponding process cartridge PY.

[0020] The laser light L2 deflected by the rotating polygon mirror 4 passes through the first imaging lens 8a, and then the optical path is deflected by the folding mirrors 10a and 10b corresponding to the process cartridge PM. Then, the laser light L2 passes through the second imaging lens 9b and the opening of the lid member 5, and scans the surface of the photosensitive drum 11b at a constant speed while forming a spot on the photosensitive drum 11b of the corresponding process cartridge PM.

[0021] The laser beam L3 deflected by the rotating polygon mirror 4 passes through the first imaging lens 8b and then has its optical path deflected by the folding mirror 10d corresponding to the process cartridge PC. Then, the laser beam L3 passes through the second imaging lens 9c, the folding mirror 10e, and the opening of the lid member 5, and scans the surface of the photosensitive drum 11c of the corresponding process cartridge PC at a constant speed while forming a spot on the photosensitive drum 11c.

[0022] The laser beam L4 deflected by the rotating polygon mirror 4 passes through the first imaging lens 8b and then has its optical path deflected by the folding mirror 10f corresponding to the process cartridge PK. Then, the laser beam L4 passes through the second imaging lens 9d and the opening of the lid member 5, and scans the surface of the photosensitive drum 11d of the corresponding process cartridge PK at a constant speed while forming a spot on the photosensitive drum 11d.

[0023] [Replacement of Process Cartridge] Figs. 3 to 6 are diagrams for explaining the method of replacing the process cartridge in the image forming apparatus 1. In each of the process cartridges PY, PM, PC, and PK, as the toner (developer) stored in the developing unit 14 is consumed and decreased as image formation is performed. Then, when there is no toner and image formation cannot be performed, replacement with a new process cartridge is carried out. The process cartridges PY, PM, PC, and PK in this embodiment are placed on the drawer-type cartridge tray 40 (moving unit). Therefore, the replacement of the process cartridge is performed by pulling out the cartridge tray 40 from the image forming apparatus 1 to the front side in Fig. 3, replacing the corresponding process cartridge, and then storing the cartridge tray 40 in the image forming apparatus 1 again.

[0024] [Door of Image Forming Apparatus] FIG. 3 is a schematic cross-sectional view of the image forming apparatus for explaining the maintenance door 41 of the image forming apparatus 1, and FIG. 3 shows a state where the door 41 is opened. At one end of the door 41, a gripping portion 41a (finger-hooking portion) for opening and closing the door 41 is provided, and the other end is rotatable about the horizontal axis 42. As shown in FIG. 3, the door 41 is opened and closed when the cartridge tray 40 is pulled out or the cartridge tray 40 is stored inside the image forming apparatus 1. Note that FIG. 1 shows both the state where the door 41 is closed and the state where it is opened. When the door 41 is opened, an opening 50 through which the cartridge tray 40 passes is formed. The door 41 is an opening / closing member that can take a position closing the opening 50 and a position opening it.

[0025] FIG. 4 is a perspective view showing a state where the door 41 is opened and the cartridge tray 40 is stored in the image forming apparatus 1. On the other hand, FIG. 5 is a perspective view showing a state where the door 41 is opened and the cartridge tray 40 is pulled out from the image forming apparatus 1. As shown in FIG. 4, the horizontal axis 42 as a hinge of the door 41 passes through the left and right sides in the figure, and the door 41 is rotatable with respect to the image forming apparatus 1 about the horizontal axis 42. That is, the door 41 can be rotated about the horizontal axis 42 so as to stand up in the upward direction in the figure to close the opening 50 of the image forming apparatus 1. Also, by rotating the door 41 about the horizontal axis 42 so as to fall to the front side (lower right side in the figure) of the image forming apparatus 1, the opening 50 can be opened. Inside the left frame 60L and the right frame 60R that form the frame of the image forming apparatus 1, a pair of left and right tray holding members 61L and 61R for holding the cartridge tray 40 are disposed. The tray holding members 61L and 61R are provided facing each other, and the cartridge tray 40, which is a frame-shaped member, is sandwiched between the tray holding member 61L and the tray holding member 61R.

[0026] Then, as shown in FIG. 5, since the cartridge tray 40 is held by the tray holding members 61L and 61R, it is movable in the front-rear direction along the tray holding members 61L and 61R. Process cartridges PY, PM, PC, and PK are placed on and supported by the cartridge tray 40, and each process cartridge is removably mounted individually as required.

[0027] The replacement of the process cartridge is performed with the cartridge tray 40 pulled out to the outside of the image forming apparatus 1. Then, after replacing the process cartridge that needs to be replaced among the process cartridges PY, PM, PC, and PK, the cartridge tray 40 is returned (inserted) into the image forming apparatus 1 and fixed (stored) at a predetermined position (storage position). In the process of inserting the cartridge tray 40 into the image forming apparatus 1, the process cartridges are inserted into the image forming apparatus 1 in the order of PY, PM, PC, and PK and stored in the storage section T (the area surrounded by the dotted line in FIG. 6). The storage section T is an area adjacent to the position facing the lid member 5 of the optical scanning device 2.

[0028] [Process Cartridge Misloading Prevention Mechanism] Next, the process cartridge misloading prevention mechanism of this embodiment will be described with reference to FIGS. 6, 7, and 8.

[0029] [Process Cartridge PK Misloading Prevention Mechanism] (When each process cartridge is mounted in the correct position) FIG. 6 is a view showing a state in which the cartridge tray 40 with each of the process cartridges PY, PM, PC, and PK mounted in a normal position is stored in the storage section T (a region surrounded by a dotted line in the figure) of the image forming apparatus 1. In FIG. 6, the white arrows indicate the direction in which the cartridge tray 40 is stored (leftward arrow in the figure) and the direction in which it is pulled out (rightward arrow in the figure). The same applies to the white arrows in the figures after FIG. 6. The misloading prevention mechanism for the process cartridge PK includes a misloading prevention portion 6K, which is a rib portion provided on the lid member 5 of the optical scanning device 2 and protruding toward the process cartridge PK side, and a rib portion provided on the upper part in the vertical direction of the process cartridge PK and facing the lid member 5. In FIG. 6, only the misloading prevention mechanism for the process cartridge PK is shown, and the misloading prevention mechanisms for the process cartridges PM and PC, which will be described later, are not shown.

[0030] The misloading prevention portion 6K provided on the lid member 5, which also serves as a misloading detection portion, has a trapezoidal shape when viewed from the left side of the image forming apparatus 1 as shown in FIG. 6. The bottom surface 6Kb of the misloading prevention portion 6K facing the process cartridge PK is a horizontal surface and extends downward in the vertical direction beyond the zenith portion K4, which is the plane portion closest to the optical scanning device 2 of the rib portion K3 (see FIG. 8) of the process cartridge PK. As shown in FIG. 6, the process cartridges PY, PM, and PC have rib portions facing the lid member 5 at the upper part of the process cartridge, similar to the process cartridge PK. The top surfaces Y1, M1, and C1 are formed at heights lower than the zenith portions of the rib portions of the respective process cartridges PY, PM, and PC and at a height where the bottom surface 6Kb of the misloading prevention portion 6K does not come into contact. Therefore, in the process of inserting the cartridge tray 40 into the image forming apparatus 1, the process cartridges PY, PM, and PC do not come into contact with the misloading prevention portion 6K, and the cartridge tray 40 is stored in the normal position of the storage portion T. The process cartridge PK also has a top surface K1 formed at a height lower than the zenith portion of the rib portion of the process cartridge and at a height where the bottom surface 6Kb of the misloading prevention portion 6K does not come into contact, similar to the other process cartridges PY, PM, and PC. However, the top surface K1 of the process cartridge PK is blocked by an interference wall K2, which is a wall portion standing upright in the upper vertical direction toward the lid member 5 in the middle of the downstream side in the direction of inserting the cartridge tray 40. As shown in FIG. 6, when the process cartridge PK is properly mounted in the normal position of the cartridge tray 40, there is a gap between the collision wall 6Ka of the misloading prevention portion 6K and the interference wall K2, and they are configured not to come into contact.

[0031] (When the process cartridge PK is misloaded) Next, the case where the process cartridge PK is misinstalled will be described. FIG. 7 is a diagram for explaining a state when, as an example of misinstallation, the process cartridge PK is misinstalled, that is, when the cartridge tray 40 is inserted into the image forming apparatus 1 with the process cartridge PK installed in the position of the process cartridge PM. In FIG. 7, since the process cartridge PK is installed in the position of the process cartridge PM, the process cartridge PM is installed in the position of the process cartridge PK. When the cartridge tray 40 is inserted with the process cartridge PK installed in the position of the process cartridge PM, the top surface Y1 of the process cartridge PY installed in the normal position is lower than the bottom surface 6Kb of the misinstallation prevention portion 6K. Therefore, the process cartridge PY passes through the misinstallation prevention portion 6K without contacting the misinstallation prevention portion 6K. Then, when the cartridge tray 40 is further inserted into the image forming apparatus 1, the collision wall 6Ka of the misinstallation prevention portion 6K contacts the interference wall K2 of the process cartridge PK installed in the position of the process cartridge PM. Since the collision wall 6Ka of the misinstallation prevention portion 6K is in contact with the interference wall K2 of the process cartridge PK, the cartridge tray 40 cannot be inserted further into the image forming apparatus 1. Thus, by the misinstallation prevention mechanism of this embodiment, it is detected that the process cartridge is misinstalled, and the storage of the cartridge tray 40 in the storage portion T is prevented.

[0032] (Configuration of the misinstallation prevention mechanism of the process cartridge PK) FIG. 8 is a diagram showing a cross section when the optical scanning device 2 and the process cartridge PK are cut along the line A-A shown in FIG. 6, and is a schematic diagram for explaining the configuration of the misinstallation prevention portion 6K and the rib portion K3 of the process cartridge PK. Note that FIG. 8 is a schematic diagram when the optical scanning device 2 and the process cartridge PK are viewed from the rear side to the front side of the image forming apparatus 1 in FIG. 6.

[0033] In FIG. 8, the misloading prevention portion 6K of the lid member 5 is provided at opposing positions near both ends in the longitudinal direction of the process cartridge PK of the optical scanning device 2 (which is also the direction orthogonal to the moving direction of the cartridge tray 40). Also, interference walls K2 are provided at positions corresponding to the misloading prevention portions 6K of the process cartridge PK. On the other hand, the process cartridge PK has, at the upper vertical portion facing the optical scanning device 2, rib portions K3 having top surface portions K1 in a concave shape on both sides in the longitudinal direction (left - right direction in the figure) and interference walls K2 standing up from the top surface portions K1. Further, the rib portion K3 has a zenith portion K4 facing the optical scanning device 2. Although not shown, when viewed from the side of the optical scanning device 2 facing the rib portion K3 of the process cartridge PK, the shape of the rib portion K3 can be said to be a T - shape with a wide width at the central bar portion. And when the process cartridge PK is misloaded, the collision wall 6Ka of the misloading prevention portion 6K is configured to contact the interference wall K2 of the process cartridge PK. Note that in FIG. 7, the case where the process cartridge PK is misloaded onto the process cartridge PM has been described. Even when the process cartridge PK is misloaded to the mounting positions of the process cartridges PC and PY, during the process of inserting the cartridge tray 40 into the image forming apparatus 1, the collision wall 6Ka contacts the interference wall K2 of the misloaded process cartridge PK. Therefore, the cartridge tray 40 is not stored in the storage portion T.

[0034] [Misloading prevention mechanism for process cartridges PM and PC] As described above, the misloading prevention mechanism for detecting misloading when the process cartridge PK is misloaded to the positions of other process cartridges in the cartridge tray 40 has been explained. In this embodiment, the process cartridges PM and PC also have a similar misloading prevention mechanism, and the misloading prevention mechanisms for the process cartridges PM and PC will be explained with reference to FIGS. 9 to 13.

[0035] (When each process cartridge is mounted in the normal position) FIG. 9 is a view showing a state in which the cartridge tray 40 with each of the process cartridges PY, PM, PC, and PK mounted at their normal positions is stored in the storage section T of the image forming apparatus 1.

[0036] In FIG. 9, the misloading prevention mechanism of the process cartridge PM includes a misloading prevention portion 6M protruding from the lid member 5 of the optical scanning device 2 toward the process cartridge PM, and a rib portion M3 (see FIG. 11) provided on the upper portion of the process cartridge PM. As shown in FIG. 9, the misloading prevention portion 6M has a trapezoidal shape when viewed from the left side of the image forming apparatus 1, similar to the misloading prevention portion 6K. The bottom surface 6Mb of the misloading prevention portion 6M facing the process cartridge PM is a horizontal surface, and extends downward in the vertical direction beyond the zenith portion M4 (see FIG. 11), which is the plane portion closest to the optical scanning device 2 of the rib portion M3 of the process cartridge PM. The process cartridge PM has a top surface portion M1 formed at a height lower than the zenith portion M4 of the rib portion of the process cartridge PM and at which the bottom surface 6Mb of the misloading prevention portion 6M does not come into contact. In the process cartridge PM, similar to the process cartridge PK, a part of the top surface portion M1 is blocked by an interference wall M2 standing upright in the upper vertical direction toward the lid member 5 in the middle of the downstream side in the direction in which the cartridge tray 40 is inserted. As shown in FIG. 9, when the process cartridge PM is mounted at the normal position in the cartridge tray 40, there is a gap between the collision wall 6Ma of the misloading prevention portion 6M and the interference wall M2, and they are configured not to come into contact.

[0037] In addition, the misloading prevention mechanism of the process cartridge PC is composed of a misloading prevention portion 6C protruding from the lid member 5 of the optical scanning device 2 toward the process cartridge PC side (image forming unit side), and a rib portion C3 (see FIG. 10) provided on the upper portion of the process cartridge PC. As shown in FIG. 9, the misloading prevention portion 6C has a trapezoidal shape when viewed from the left side of the image forming apparatus 1, similar to the misloading prevention portion 6M. The bottom surface 6Cb of the misloading prevention portion 6C facing the process cartridge PC is a horizontal surface, and extends downward in the vertical direction beyond the zenith portion C4 (see FIG. 10), which is the plane portion closest to the optical scanning device 2 of the rib portion C3 of the process cartridge PC. The process cartridge PC is formed with a top surface portion C1 at a height lower than the zenith portion C4 of the rib portion of the process cartridge PC and where the bottom surface 6Cb of the misloading prevention portion 6C does not come into contact. In the process cartridge PC, similar to the process cartridge PC, a part of the top surface portion C1 is blocked by an interference wall C2 erected vertically upward toward the lid member 5 in the middle of the downstream side in the direction of inserting the cartridge tray 40. As shown in FIG. 9, when the process cartridge PC is mounted at the normal position of the cartridge tray 40, there is a gap between the collision wall 6Ca of the misloading prevention portion 6C and the interference wall C2, and they are configured not to come into contact.

[0038] (Configuration of the misloading prevention mechanism of the process cartridge PC) FIG. 10 is a cross-sectional view showing the optical scanning device 2 and the process cartridge PC cut along the line B-B shown in FIG. 9, and is a schematic diagram for explaining the configuration of the misloading prevention portion 6C and the rib portion C3 of the process cartridge PC. Note that FIG. 10 is a schematic diagram when the optical scanning device 2 and the process cartridge PC are viewed from the rear side to the front side of the image forming apparatus 1 in FIG. 9.

[0039] In FIG. 10, the misloading prevention portion 6C of the lid member 5 is provided at a position more central than the position where the above-described misloading prevention portion 6K is provided in the longitudinal direction of the process cartridge PC of the optical scanning device 2. Further, an interference wall C2 is provided at a position corresponding to the misloading prevention portion 6C of the process cartridge PC. As described above, the process cartridge PC has top surface portions C1 in a concave shape on both sides in the longitudinal direction (left - right direction in the figure) in the upper vertical direction facing the optical scanning device 2. Furthermore, the process cartridge PC has a rib portion C3 having an interference wall C2 standing upright so as to contact the collision wall 6Ca of the misloading prevention portion 6C from a part of the top surface portion C1, and the rib portion C3 has a zenith portion C4 facing the optical scanning device 2. Although not shown, when viewed from the side of the optical scanning device 2 facing the rib portion C3 of the process cartridge PC, the shape of the rib portion C3 can be said to be a T - shape with a wide width in the central rod portion. And when the process cartridge PC is misloaded, the collision wall 6Ca of the misloading prevention portion 6C is configured to contact the interference wall C2 of the process cartridge PC. Note that the rib portion C3 of the process cartridge PC has a shorter width in the longitudinal direction (left - right direction in the figure) than the rib portion K3 of the process cartridge PK so that the collision wall 6Ka of the misloading prevention portion 6K does not contact it.

[0040] (Configuration of the misloading prevention mechanism of the process cartridge PM) FIG. 11 is a diagram showing a cross - section when the optical scanning device 2 and the process cartridge PM are cut along the C - C line shown in FIG. 9, and is a schematic diagram for explaining the configuration of the misloading prevention portion 6M and the rib portion M3 of the process cartridge PM. Note that FIG. 11 is a schematic diagram when the optical scanning device 2 and the process cartridge PM are viewed from the rear side to the front side of the image forming apparatus 1 in FIG. 9.

[0041] In FIG. 11, the misloading prevention portion 6M of the lid member 5 is provided at a position more central than the position where the above-described misloading prevention portion 6C is provided in the longitudinal direction of the process cartridge PM of the optical scanning device 2. Also, an interference wall M2 is provided at a position corresponding to the misloading prevention portion 6M of the process cartridge PC. As described above, the process cartridge PM has top surface portions M1 having a concave shape on both sides in the longitudinal direction (left - right direction in the figure) in the upper vertical direction facing the optical scanning device 2. Further, the process cartridge PM has a rib portion M3 having an interference wall M2 standing upright so as to contact the collision wall 6Ma of the misloading prevention portion 6M from a part of the top surface portion M1, and the rib portion M3 has a zenith portion M4 facing the optical scanning device 2. Although not shown, when viewed from the side of the optical scanning device 2 facing the rib portion M3 of the process cartridge PM, the shape of the rib portion M3 can be said to be a T - shape with a wide width in the central bar portion. And when the process cartridge PM is misloaded, the collision wall 6Ma of the misloading prevention portion 6M is configured to contact the interference wall M2 of the process cartridge PM. Note that the rib portion M3 of the process cartridge PM has a shorter width in the longitudinal direction (left - right direction in the figure) compared to the rib portions K3, C3 of the process cartridges PK, PC so that the collision walls 6Ka, 6Ca of the misloading prevention portions 6K, 6C do not contact.

[0042] (Misloading prevention mechanism of the process cartridge PY) FIG. 12 is a schematic diagram showing a cross - section when the optical scanning device 2 and the process cartridge PY are cut along the line D - D shown in FIG. 9. Note that FIG. 12 is a schematic diagram when the optical scanning device 2 and the process cartridge PY are viewed from the rear side to the front side of the image forming apparatus 1 in FIG. 9.

[0043] In FIG. 12, the optical scanning device 2 is not provided with a misloading prevention mechanism such as misloading prevention portions 6M, 6C, and 6K for preventing misloading of the process cartridges PM, PC, and PK for the process cartridge PY mounted on the foremost part of the cartridge tray 40. The process cartridge PY has a top surface portion Y1 with a concave shape on both sides in the longitudinal direction and rib portions Y3 standing upright from the top surface portion Y1 at an upper part in the vertical direction facing the optical scanning device 2. Further, the rib portion Y3 has a zenith portion Y4 facing the optical scanning device 2. Since the process cartridge PY is not provided with a misloading prevention mechanism, it does not have an interference wall like the process cartridges PM, PC, and PK. Although not shown, when viewed from the side of the optical scanning device 2 facing the rib portion Y3 of the process cartridge PY, the shape of the rib portion Y3 can be said to be an I shape. Also, the rib portion Y3 of the process cartridge PY is shorter in width in the longitudinal direction (left - right direction in the figure) compared to the rib portions K3, C3, and M3 of the process cartridges PK, PC, and PM so that the collision walls 6Ka, 6Ca, and 6Ma of the misloading prevention portions 6K, 6C, and 6M do not come into contact with it.

[0044] Note that in this embodiment, the lid member 5 side of the optical scanning device 2 is also not provided with a mechanism for preventing misloading of the process cartridge PY. In the case of misloading of the process cartridge PY, misloading of at least one or more other process cartridges also occurs simultaneously, so there is no problem due to the lack of a misloading prevention mechanism for the process cartridge PY.

[0045] As described above, the misloading prevention parts 6C, 6M, 6K of the optical scanning device 2 and the interference walls C2, M2, K2 are provided with their formation positions shifted for each process cartridge on both sides across the center in the longitudinal direction of each process cartridge as shown in FIGS. 8, 10, and 11. Specifically, the positions where the misloading prevention parts 6M, 6C, 6K are formed on the lid member 5 corresponding to the process cartridges PM, PC, PK are as follows. That is, the positions where the misloading prevention parts 6M, 6C, 6K are formed are shifted in the direction of the end orthogonal to the direction in which the cartridge tray 40 moves to the storage position in the order of the process cartridges PM, PC, PK. The order of the process cartridges PM, PC, PK is also the direction from the downstream side to the upstream side in the direction in which the cartridge tray 40 moves to the storage position. Similarly, regarding the positions where the interference walls M2, C2, K2 of the process cartridges PM, PC, PK are formed, they are shifted in the direction of the end orthogonal to the direction in which the cartridge tray 40 moves to the storage position in the order of the process cartridges PM, PC, PK. Therefore, when the process cartridge is mounted in the normal position, the respective collision walls and the respective interference walls do not contact each other during the insertion process. As a result, the cartridge tray 40 is stored in the storage part T.

[0046] (When the process cartridge is misloaded) Next, the case where the process cartridge PC is misloaded will be described. FIG. 13 is a diagram for explaining the state when the cartridge tray 40 is inserted into the image forming apparatus 1 with the process cartridge PC mounted in the position of the process cartridge PM as another example of misloading different from FIG. 7 described above.

[0047] When the process cartridge PC is inserted into the cartridge tray 40 with a misinstalled cartridge, the top surface Y1 of the process cartridge PY installed in the normal position is lower than the bottom surfaces 6Kb, 6Cb, and 6Mb of the anti-misinstallation parts 6K, 6C, and 6M, respectively. Therefore, the process cartridge PY passes through without contacting the anti-misinstallation parts 6K, 6C, and 6M. Then, when the cartridge tray 40 is further inserted into the image forming apparatus 1, since the installation positions of the anti-misinstallation part 6K and the interference wall C2 are shifted in the longitudinal direction of the process cartridge, the process cartridge PC passes through without contacting the anti-misinstallation part 6K. However, when the misinstalled process cartridge PC passes through the anti-misinstallation part 6C, the collision wall 6Ca and the interference wall C2 come into contact with each other. And since the collision wall 6Ca of the anti-misinstallation part 6C is in contact with the interference wall C2 of the process cartridge PC, the cartridge tray 40 can no longer be inserted into the image forming apparatus 1 any further.

[0048] Also, for example, when the process cartridge PC is misinstalled at the position of the process cartridge PY, or when it is misinstalled at the position of the process cartridge PM, the collision wall 6Ca and the interference wall C2 come into contact with each other when the process cartridge PC passes through the anti-misinstallation part 6C. As a result, the cartridge tray 40 can no longer be inserted into the image forming apparatus 1 any further.

[0049] The above has described the case of misinstallation of the process cartridge PC. The same applies to the misinstallation of the process cartridge PM. For example, consider the case where a cartridge tray 40 with a process cartridge PM misinstalled at the position of the process cartridge PY is inserted. In this case, since the installation positions of the misinstallation prevention portion 6K and the interference wall M2 are displaced in the longitudinal direction of the process cartridge, the process cartridge PM passes through without contacting the misinstallation prevention portion 6K. Similarly, for the misinstallation prevention portion 6C and the interference wall M2, since the installation positions in the longitudinal direction of the process cartridge are displaced, the process cartridge PM passes through without contacting the misinstallation prevention portion 6C. However, when the misinstalled process cartridge PM passes through the misinstallation prevention portion 6M, the collision wall 6Ma and the interference wall M2 come into contact. And since the collision wall 6Ma of the misinstallation prevention portion 6M is in contact with the interference wall M2 of the process cartridge PM, the cartridge tray 40 can no longer be inserted into the image forming apparatus 1.

[0050] As described above, when a cartridge tray 40 with a misinstalled process cartridge is inserted into the image forming apparatus 1, the collision wall of the misinstallation prevention portion 6 corresponding to the misinstalled process cartridge contacts the interference wall, thereby detecting the misinstallation. Then, it can be known that the misinstalled process cartridge is one of the process cartridges PM, PC, and PK by any one of the misinstallation prevention portions 6M, 6C, and 6K for the collision wall of the misinstallation prevention portion 6 that has contacted the interference wall. Further, the installation position of the misinstalled process cartridge can be known from the installation position of the cartridge tray 40 on which the process cartridge with the collision wall of the misinstallation prevention portion 6 contacting the interference wall was installed.

[0051] [Shock Absorbing Mechanism When Process Cartridge is Misinstalled] Next, a mechanism for mitigating the shock when the process cartridge is misinstalled will be described.

[0052] [Mounting Mechanism of the Cover Member of the Optical Scanning Device to the Housing] FIG. 14 is a perspective view of the optical scanning device 2 with the lid member 5 attached to the housing 3 as viewed from the lid member 5 side. In FIG. 14, the four elongated openings in the left-right direction of the lid member 5 are the openings from which the laser light irradiated onto the photosensitive drum 11 is emitted, and the pair of trapezoidal members provided in the left-right direction between the respective openings are the above-described misattachment prevention portions 6M, 6C, 6K. As shown in FIG. 14, the lid member 5 has fixing portions 5a, 5b, 5c, 5d of a plurality of snap-fit structures for fixing the lid member 5 to the housing 3. The fixing portions 5a, 5b, 5c, 5d are provided at the four corners of the housing 3 and are elastically fixed to the housing 3 by a snap-fit structure. The snap-fit structures of the fixing portions 5a, 5b, 5c, 5d are integrally formed with the lid member 5 and have a rectangular shape with openings. When the lid member 5 is assembled to the housing 3, the snap-fit structures of the fixing portions 5a, 5b, 5c, 5d elastically bend to overcome the protruding portions 3a, 3b, 3c, 3d provided on the housing 3. Then, the protruding portions 3a, 3b, 3c, 3d engage with the openings of the snap-fit structures of the fixing portions 5a, 5b, 5c, 5d. In this way, the lid member 5 is held by the housing 3 when the protruding portions 3a, 3b, 3c, 3d of the housing 3 protrude from the openings provided in the snap-fit structures of the fixing portions 5a, 5b, 5c, 5d and engage therewith. Note that, in FIG. 14, the U-shaped portion surrounded by an ellipse including the misattachment prevention portion 6C, and the holes 5e, 5f will be described with reference to FIG. 15. Also, the bosses 3g, 3h and the seating surface 3i shown in FIG. 14 will be described with reference to FIG. 16.

[0053] [Configuration of Impact Mitigation Mechanism by Lid Member of Optical Scanning Device] Subsequently, the impact mitigation mechanism by the lid member of this embodiment will be described. FIG. 15 is a diagram for explaining the impact mitigation operation when the impact wall of the misattachment prevention portion 6 provided on the lid member 5 contacts the interference wall of the process cartridge due to misattachment, and is an enlarged view of the U-shaped portion in FIG. 14.

[0054] FIG. 15(a) is a view showing the state of the U portion when each process cartridge is mounted at a normal position in the cartridge tray 40 and the cartridge tray 40 is stored in the storage portion T of the image forming apparatus 1. The lid member 5 is held by the housing 3 by the snap fit structure of the fixing portions 5a, 5b, 5c, 5d described above, but only by that, the position of the lid member 5 with respect to the housing 3 is not determined. Therefore, the lid member 5 of the present embodiment is provided with holes 5e, 5f which are openings, and bosses 3e, 3f provided in the housing 3 and standing upright in the direction of the lid member 5 are inserted through the holes 5e, 5f. Then, springs 11, 12 which are first elastic members bridging the holes 5e, 5f are installed on the lid member 5, and by the springs 11, 12, the bosses 3e, 3f (first protrusions) protruding from the holes 5e, 5f are biased toward the rear side (the insertion direction side of the cartridge tray 40) of the image forming apparatus 1. In the present embodiment, the width in the bridging direction of the hole 5e of the spring 11 and the diameter of the boss 3e, and the width in the bridging direction of the hole 5f of the spring 12 and the diameter of the boss 3f are respectively in a fitting relationship. Then, by the biasing of the springs 11, 12, the bosses 3e, 3f are abutted against end faces 5e1, 5f1 located on the downstream side in the insertion direction of the cartridge tray 40 of the holes 5e, 5f (first position). As a result, the positioning of the lid member 5 with respect to the housing 3 is performed by the engagement between the fixing portion of the lid member 5 and the housing 3 by the snap fit structure described above.

[0055] Next, with reference to FIG. 15(b), the shock mitigation operation of the lid member 5 when the process cartridge is misinstalled will be described. FIG. 15(b) is a diagram showing the state of the lid member 5 when the collision wall of the misinstallation prevention portion 6 provided on the lid member 5 collides with the interference wall of the process cartridge during the process of inserting the cartridge tray 40 with the misinstalled process cartridge into the image forming apparatus 1. When the collision wall of the misinstallation prevention portion 6 collides with the interference wall of the misinstalled process cartridge, the lid member 5 receives an impact in the insertion direction of the cartridge tray 40. As described above, the lid member 5 is only biased by the elastic forces of the springs 11 and 12 in the insertion direction of the cartridge tray 40, and against the biasing forces of the springs 11 and 12, it temporarily moves in the insertion direction of the cartridge tray together with the impact at the time of collision (to the second position). Since the widths of the holes 5e and 5f of the lid member 5 in the insertion direction of the cartridge tray 40 are set to be larger than the amount of movement of the lid member 5, the bosses 3e and 3f of the housing 3 do not hit the end faces on the side opposite to the insertion direction of the cartridge tray 40 of the holes 5e and 5f. Note that the amount of movement of the lid member 5 is the length (distance) of the gap between the collision wall of the misinstallation prevention portion 6 and the interference wall of the process cartridge when the process cartridge is installed in the normal position.

[0056] Since the user cannot insert the cartridge tray 40 into the image forming apparatus 1, the user notices the misinstallation of the process cartridge and performs an operation of pulling out the cartridge tray 40 from the image forming apparatus 1. As a result, the lid member 5 moves in the direction opposite to the insertion direction of the cartridge tray 40. Consequently, the lid member 5 returns by the biasing forces of the springs 11 and 12 with an increased amount of deflection until the bosses 3e and 3f abut against the end faces 5e1 and 5ef of the holes 5e and 5f (the state shown in FIG. 15(a)). In this way, by elastically biasing the lid member 5 so that it can move in the direction of receiving the impact, it becomes possible to mitigate the impact with the elastic force.

[0057] [Configuration of the Shock Mitigation Mechanism by the Housing of the Optical Scanning Device] Next, with reference to FIG. 16, the shock mitigation mechanism of the housing 3 of the optical scanning device 2 will be described.

[0058] FIG. 16(a) is a view of the frame (Ff, Fr) installation part of the optical scanning device 2 as seen from the process cartridge side when the cartridge tray 40 with the process cartridge mounted in the normal position is stored in the storage part T of the image forming apparatus 1. Further, FIG. 16(b) is a view of the optical scanning device 2 in the state shown in FIG. 16(a) as seen from above the optical scanning device 2. Note that the frame (Ff, Fr) installation part is an installation part for fixing the optical scanning device 2 to the front frame Ff and the rear frame Fr of the image forming apparatus 1.

[0059] As shown in FIG. 16(a), in the optical scanning device 2, the seating surfaces 3i1, 3i2 of the housing 3 are in contact with the frame Fr of the image forming apparatus 1, and the seating surface 3i3 of the housing 3 is in contact with the frame Ff of the image forming apparatus 1. Then, by the seating surfaces 3i1, 3i2 of the housing 3 being in contact with the frame Fr of the image forming apparatus 1, the bosses 3g, 3h (second protrusions) provided on the seating surfaces 3i1, 3i2 of the housing 3 respectively penetrate through the holes Fr1, Fr2 provided in the frame Fr. Further, as shown in FIG. 16(b), the ends (the ends on the side in the direction in which the cartridge tray 40 is inserted) of the ribs 3j, 3k erected on the seating surfaces 3i1, 3i2 of the housing 3 of the optical scanning device 2 are biased by springs 13, 14 which are the second elastic members. The springs 13, 14 bias the ribs 3j, 3k provided on the frame Fr in the direction opposite to the insertion direction of the cartridge tray 40. Thereby, the bosses 3g, 3h are abutted against the end faces Fr3, Fr4 on the side opposite to the insertion direction of the cartridge tray 40 of the holes Fr1, Fr2 (third position). On the other hand, the rib 3l erected on the seating surface 3i3 of the housing 3 of the optical scanning device 2 is biased toward the frame Ff side by a spring 15 bridged so as to straddle the rib 3l.

[0060] In this embodiment, the width in the crosslinking direction of the hole Fr1 of the frame Fr of the spring 13 and the diameter of the boss 3g, and the width in the crosslinking direction of the hole Fr2 of the frame Fr of the spring 14 and the diameter of the boss 3h are in a fitting relationship respectively. Then, due to the biasing of the springs 13 and 14, the bosses 3g and 3h are respectively abutted against the end faces Fr3 and Fr4 of the holes Fr1 and Fr2, and the seating surfaces 3i1, 3i2, and 3i3 of the housing 3 are fixed to the frames Fr and Ff. Thereby, the positions of the image forming apparatus 1 of the optical scanning apparatus 2 with respect to the frames Ff and Fr are determined.

[0061] [Shock Absorbing Operation of Shock Absorbing Mechanism by Housing of Optical Scanning Apparatus] Next, with reference to FIG. 16(c), the shock absorbing operation of the optical scanning apparatus 2 when the process cartridge is misloaded will be described. FIG. 16(c) is a diagram showing the state of the frame (Ff, Fr) installation portion of the optical scanning apparatus when the interference wall of the process cartridge misloaded in the cartridge tray 40 collides with the collision wall of the misloading prevention portion 6 provided on the lid member 5.

[0062] When the collision wall of the misloading prevention portion 6 collides with the interference wall of the misloaded process cartridge, the optical scanning apparatus 2 receives an impact in the insertion direction of the cartridge tray 40. As described above, the optical scanning apparatus 2 is only biased by the elastic forces of the springs 13 and 14 with respect to the insertion direction of the cartridge tray 40. Therefore, the optical scanning apparatus 2 (housing 3) temporarily moves in the insertion direction of the cartridge tray 40 together with the impact at the time of collision against the biasing forces of the springs 13 and 14 (the fourth position). The widths in the insertion direction of the cartridge tray 40 of the holes Fr1 and Fr2 of the frame Fr are set to be larger than the moving amount of the optical scanning apparatus 2. Therefore, the bosses 3g and 3h of the housing 3 do not hit the end faces on the side opposite to the insertion direction of the cartridge tray 40 of the holes Fr1 and Fr2. Note that the moving amount of the optical scanning apparatus 2 is the length (distance) of the gap between the collision wall of the misloading prevention portion 6 and the interference wall of the process cartridge when the process cartridge is mounted at the normal position.

[0063] Since the user cannot insert the cartridge tray 40 into the image forming apparatus 1, the user notices the misloading of the process cartridge and performs an operation of pulling out the cartridge tray 40 from the image forming apparatus 1. As a result, the optical scanning device 2 moves in a direction opposite to the insertion direction of the cartridge tray 40. As a result, the optical scanning device 2 returns until the bosses 3g and 3h abut against the end faces Fr3 and Fr4 of the holes Fr1 and Fr2 by the biasing forces of the springs 13 and 14 with an increased amount of deflection (the state shown in FIG. 16(a)). In this way, by elastically biasing the optical scanning device 2 so that it can move in the direction of receiving an impact, the impact on the optical scanning device can be reduced, and a change in optical characteristics such as the spot diameter can be suppressed.

[0064] In this embodiment, the case where the process cartridges PK, PC, and PM are misloaded at positions where the process cartridges PM, PM, and PY downstream in the insertion direction of the cartridge tray 40 are mounted from the normal positions of the cartridge tray 40 has been described. Conversely, the above description can also be said to be an example of the case where the process cartridges PM, PM, and PY are misloaded at the mounting positions of PK, PC, and PM of the cartridge tray 40 upstream in the insertion direction of the cartridge tray 40 from the normal positions. Also, although no misloading prevention portion and interference wall are provided for the process cartridge PY, misloading the process cartridge PY is synonymous with other process cartridges being misloaded to the position of the process cartridge PY. Therefore, if misloading prevention of the remaining three process cartridges PM, PC, and PK is provided, it means that the misloading prevention mechanism is functioning.

[0065] Also, in this embodiment, the configuration in which the process cartridges PY, PM, PC, and PK are mounted on the cartridge tray 40 in this order has been described. However, the mounting order of the process cartridges may be arbitrary. That is, as long as the configuration of the misloading prevention portion 6 of the lid member 5 remains the configuration shown in FIG. 9, for example, it is sufficient that the interference wall of the rib portion of the process cartridge mounted on the cartridge tray 40 corresponds to the collision wall of the misloading prevention portion 6. Thus, in a color image forming apparatus that uses a plurality of process cartridges, there is no need to add dedicated parts for preventing misloading, so the miniaturization of the image forming apparatus 1 is not impaired.

[0066] As described above, according to this embodiment, it is possible to prevent misloading of the process cartridge without impairing the miniaturization of the image forming apparatus.

Example

[0067] In Example 1, an example of preventing misloading of a process cartridge in a color image forming apparatus having a configuration in which a plurality of process cartridges are mounted on a cartridge tray has been described. In Example 2, an example of preventing misloading of a process cartridge in a color image forming apparatus having a configuration in which the process cartridge can be individually replaced will be described.

[0068] [Configuration of Optical Scanning Device] FIG. 17 is a schematic cross-sectional view for explaining the configuration of a storage unit T for process cartridges PY, PM, PC, and PK of the image forming apparatus 1 according to the present embodiment, and an optical scanning device 2 that irradiates laser light onto the photosensitive drums 11 of the process cartridges PY, PM, PC, and PK adjacent to the storage unit T. In Example 1, the optical scanning device 2 was configured to be installed above the process cartridges PY, PM, PC, and PK in the vertical direction and irradiate laser light onto the photosensitive drums 11 of the process cartridges PY, PM, PC, and PK installed below in the vertical direction. On the other hand, in the present embodiment, the optical scanning device 2 is configured to be installed below the process cartridges PY, PM, PC, and PK in the vertical direction and irradiate laser light onto the photosensitive drums 11 of the process cartridges PY, PM, PC, and PK installed above in the vertical direction. Also in Example 2, the internal configuration of the optical scanning device 2 is the same as that in Example 1, and the lid member 5 is disposed on the side facing the process cartridges PY, PM, PC, and PK. In FIG. 17, members having the same functions as those in Example 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0069] The process cartridges PY, PM, PC, and PK according to the present embodiment are different from the configuration of Example 1 in that they can be individually replaced and mounted. Also, the attachment and detachment of each process cartridge are performed in the direction perpendicular to the plane of FIG. 17 (the direction of the rotation axis of the photosensitive drum 11). For example, when removing the process cartridge, it is pulled out toward the front side of the plane in the direction perpendicular to the plane of FIG. 17, and when mounting the process cartridge, it is inserted toward the back side of the plane in the direction perpendicular to the plane of FIG. 17.

[0070] And in this embodiment, in order to prevent the incorrect installation of the process cartridge, the lid member 5 of the optical scanning device 2 is provided with misinstallation prevention portions 6Y1, 6M1, 6C1, 6K1 which are convex-shaped protrusions protruding toward the process cartridges PY, PM, PC, PK. On the other hand, groove portions Y5, M5, C5, K5 having a concave shape are provided at positions facing the misinstallation prevention portions 6Y1, 6M1, 6C1, 6K1 of the lid member 5 of the process cartridges PY, PM, PC, PK. The misinstallation prevention portions 6Y1, 6M1, 6C1, 6K1 provided on the lid member 5 of the optical scanning device 2 and the groove portions Y5, M5, C5, K5 provided on the process cartridges PY, PM, PC, PK side are formed across the direction perpendicular to the plane of FIG. 17 (both ends in the longitudinal direction). Further, the groove portions Y5, M5, C5, K5 are formed with their positions shifted in the arrangement direction of the photosensitive drums for each process cartridge. The positions of the misinstallation prevention portions 6Y1, 6M1, 6C1, 6K1 provided on the lid member 5 of the optical scanning device 2 are formed with their positions shifted for each process cartridge.

[0071] FIG. 17 is a diagram showing a case where the process cartridges PY, PM, PC, PK are mounted in normal positions. In FIG. 17, since each convex portion of the misinstallation prevention portions 6Y1, 6M1, 6C1, 6K1 provided on the lid member 5 and each concave portion of the groove portions Y5, M5, C5, K5 of the process cartridges PY, PM, PC, PK correctly correspond to each other, each process cartridge is stored in the storage portion T. On the other hand, in the case of incorrect installation of the process cartridge, the convex portion of the misinstallation prevention portion provided on the lid member 5 of the optical scanning device 2 and the concave portion provided on the process cartridge do not correspond to each other. Therefore, the process cartridge cannot be stored in the storage portion T, and the user can notice the incorrect installation.

[0072] Also, regarding the impact mitigation mechanism during misloading described in Example 1, the configuration of Example 1 can be applied to this example. In this example, the optical scanning device 2 is configured to be installed at the lower part in the vertical direction of the process cartridges PY, PM, PC, and PK. This example can also be applied to a configuration in which the optical scanning device 2 is installed at the upper part in the vertical direction of the process cartridges PY, PM, PC, and PK, which is the same as that of Example 1. Further, as long as the positions where the convex portions of the misloading prevention portions 6Y1, 6M1, 6C1, and 6K1 and the concave portions of the groove portions Y5, M5, C5, and K5 of the process cartridges PY, PM, PC, and PK are formed correspond to each other, they are not limited to the positions shown in FIG. 17. As described above, in a color image forming apparatus that uses a plurality of process cartridges, there is no need to add dedicated parts for preventing misloading, so the miniaturization of the image forming apparatus 1 is not impaired.

[0073] As described above, according to this example, it is possible to prevent misloading of the process cartridge without impairing the miniaturization of the image forming apparatus.

Explanation of Reference Numerals

[0074] 2 Optical scanning device 3 Housing 5 Cover member 6M, 6C, 6K Misloading prevention portion 11 Photosensitive drum 40 Cartridge tray M2, C2, Y2 Interference wall PY, PM, PC, PK Process cartridge

Claims

1. An image forming apparatus for forming an image on a recording material, comprising: a plurality of image forming units having a photosensitive drum and performing image formation on the recording material; an optical scanning device having a plurality of light sources and irradiating the photosensitive drum of the corresponding image forming unit with laser light emitted from the light sources to form an electrostatic latent image; a moving unit on which the plurality of image forming units are mounted at predetermined positions and which is movable between the outside of the image forming apparatus and a storage position where the laser light emitted from the optical scanning device is irradiated onto the photosensitive drum of the corresponding image forming unit; wherein: the optical scanning device includes a housing that houses the plurality of light sources and a lid that covers an opening of the housing; the lid faces the image forming unit mounted on the moving unit, protrudes toward each corresponding image forming unit side, and has a plurality of mismounting detection portions that detect an image forming unit mismounted on the moving unit; the plurality of image forming units each have a wall portion that contacts the mismounting detection portion when mismounted on the moving unit and a rib portion that faces the lid; the wall portion is provided at positions of both ends of the rib portion in a direction orthogonal to the moving direction of the moving unit, at which positions the mismounting detection portion contacts when the moving unit is mismounted; each of the mismounting detection portions: is provided at a position corresponding to the plurality of image forming units when the moving unit on which the plurality of image forming units are mounted at the predetermined positions is located at the storage position; and does not contact the wall portion provided on the corresponding image forming unit when all the image forming units are mounted at the predetermined positions on the moving unit. An image forming apparatus characterized by this.

2. The position where the mismounting detection portion is formed on the lid corresponding to the image forming unit is shifted in a direction of an end portion orthogonal to a direction in which the moving unit moves to the storage position, from the downstream side to the upstream side in the direction in which the moving unit moves to the storage position. The image forming apparatus according to Claim 1, characterized by this.

3. The position of the wall portion formed on the image forming unit is shifted in the direction of the end portion of the image forming unit as the predetermined position where the image forming unit is mounted goes upstream in the direction in which the moving unit moves to the storage position. The image forming apparatus according to Claim 2, characterized by this.

4. Of the plurality of the image forming units, the image forming unit mounted on the foremost part of the moving unit when the moving unit is moved in the direction of the storage position does not have the wall portion, the image forming apparatus according to claim 3.

5. The image forming apparatus according to claim 4, wherein the lid portion does not have the misloading detection unit corresponding to the image forming unit mounted on the foremost part of the moving unit.

6. The lid portion has an opening through which a first protrusion protruding from the housing is inserted, and a first elastic member that biases the first protrusion inserted through the opening. The image forming apparatus according to claim 5, wherein the first elastic member biases the first protrusion in the direction of moving the moving unit to the storage position.

7. The lid portion is movable between a first position when all the misloading detection units are not in contact with the wall portion and a second position when the misloading detection unit is in contact with the wall portion. The image forming apparatus according to claim 6, wherein the first elastic member moves the lid portion from the second position to the first position when the misloading detection unit moves away from the wall portion.

8. Comprising a frame that supports the optical scanning device. The frame has an opening through which a second protrusion protruding from the housing of the optical scanning device is inserted, and a second elastic member that biases the second protrusion inserted through the opening. The image forming apparatus according to claim 6 or claim 7, wherein the second elastic member biases the second protrusion in a direction opposite to the direction of moving the moving unit to the storage position.

9. The housing is movable between a third position when the misloading detection unit is not in contact with the wall portion and a fourth position when the misloading detection unit is in contact with the wall portion. The image forming apparatus according to claim 8, wherein the second elastic member moves the housing from the fourth position to the third position when the misloading detection unit moves away from the wall portion.

10. The image forming apparatus according to any one of claims 1 to 9, wherein the optical scanning device is disposed above the image forming unit mounted on the moving unit in the vertical direction.

11. An image forming apparatus that forms an image on a recording material, Having a photosensitive drum, and a plurality of image forming units that form an image on a recording material. An optical scanning device having a plurality of light sources and irradiating laser light emitted from the light sources onto a photosensitive drum of the corresponding image forming unit to form an electrostatic latent image; comprising; the optical scanning device includes a housing that houses the plurality of light sources, and a lid that covers an opening of the housing; the lid faces the image forming unit, has a plurality of protruding portions that protrude toward the corresponding image forming unit side, and detect a mis-mounted image forming unit; each image forming unit has a groove portion into which the protruding portion is inserted when mounted at a corresponding position of the optical scanning device, and is disposed above the lid portion of the optical scanning device in the vertical direction; the protruding portion and the groove portion are formed in the rotational axis direction of the photosensitive drum of the image forming unit; An image forming apparatus, characterized in that positions where the protruding portions are formed are different depending on the corresponding image forming unit.

12. The image forming apparatus according to claim 11, characterized in that the image forming unit is disposed below the lid portion of the optical scanning device in the vertical direction.

Images