Image forming apparatus

Abstract

To provide an image forming apparatus comprising a cartridge tray that is small-sized and can be reliably electrically connected with process cartridges.SOLUTION: An image forming apparatus comprises a cartridge tray that holds process cartridges and is movable between an inside and outside of the image forming apparatus. The cartridge tray includes tray side plates formed of a metal material. The tray side plates each include a support part on the inside, an outside part on the outside and in an upper part, an inclined plane connecting the support part and the outside part, and a projection part bent to the outside and to a lower part of the support part, and include contacts of the cartridge tray and the process cartridges in an area surrounded by the support part, the inclined plane, and the projection part.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to an image forming apparatus that forms an image on a recording material.

Background Art

[0002] Some image forming apparatuses such as printers, copiers, and multifunction peripherals have a cartridge removably attached to a moving member that moves between the inside and outside of the apparatus main body. Patent Document 1 discloses an image forming apparatus in which a cartridge is removably attached to a moving member that moves between the inside and outside of the apparatus main body. A metal reinforcing member is provided on the moving member of Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention further develops the conventional technology. The present invention relates to an image forming apparatus having an apparatus main body and a tray unit to which a cartridge is removably attached and that includes a side plate formed of metal, and the tray unit is configured to be movable with respect to the apparatus main body. An object of the present invention is to arrange tray contacts of the tray unit that are electrically connected to cartridge contacts of the cartridge in a space-saving manner.

Means for Solving the Problems

[0005] In order to solve the above problems, the image forming apparatus of the present invention is an image forming apparatus to which a plurality of cartridges are removably attached, an apparatus main body having a main body side plate, a main body side positioning shaft supported by the main body side plate, and a main body side charging contact, A tray unit is configured to be removable and movable relative to the device body, from an external position located outside the device body to an internal position located inside the device body, wherein the plurality of cartridges are detachably mounted, and the tray unit is configured to be movable relative to the device body in an insertion direction, A first tray side plate made of metal, having a plurality of cartridge positioning portions, an inclined surface that slopes downward as it moves downstream in the insertion direction, and a positioning surface, A tray unit having, Equipped with, Each of the plurality of cartridges is a process cartridge having a photosensitive drum, a charging member configured to charge the photosensitive drum, and a cartridge-side charging contact that can contact the main body-side charging contact and is electrically connected to the charging member. The tray unit is configured to position the process cartridge at the image forming position by contacting the process cartridge. Each of the plurality of cartridge positioning units is configured to position the process cartridge at the image forming position by contacting the process cartridge, The position where the main unit-side charging contact and the cartridge-side charging contact come into contact is higher than the position where each of the plurality of cartridge positioning units comes into contact with the process cartridge. With the tray unit in the internal position, the weight of the tray unit acts on the main body positioning shaft, causing the inclined surface to receive a reaction force from the main body positioning shaft, and the reaction force includes a component force directed in the insertion direction such that the positioning surface is pressed against the main body positioning shaft. It is characterized by the following: [Effects of the Invention]

[0006] According to the present invention, the tray contacts of the tray unit, which are electrically connected to the cartridge contacts of the cartridge, can be arranged in a space-saving manner. [Brief explanation of the drawing]

[0007] [Figure 1] Overall perspective view showing a printer according to the first embodiment of this disclosure [Figure 2] Overall schematic diagram showing the internal structure of the printer [Figure 3]Front and rear perspective views showing the process cartridge. [Figure 4] Front and rear perspective views showing the cartridge tray. [Figure 5] Front and rear perspective views showing the cartridge tray with a process cartridge installed. [Figure 6] Side view showing the drive side of the cartridge tray. [Figure 7] Side view showing the non-driven side of the cartridge tray. [Figure 8] Top view of the cartridge tray [Figure 9] Perspective view showing the frame structure of the printer body. [Figure 10] Bottom perspective view showing the positioning axis of the cartridge tray. [Figure 11] (a) is a cross-sectional view showing the positioning shaft on the main body of the device engaged with the positioning groove, (b) is a cross-sectional view showing the positioning shaft and positioning groove when the cartridge tray is slightly pulled out from the installed state, (c) is a cross-sectional view showing the positioning shaft and positioning groove when the cartridge tray is further pulled out from (b), (d) is a cross-sectional view showing the positioning shaft on the cartridge tray engaged with the positioning groove, (e) is a cross-sectional view showing the positioning shaft and positioning groove when the cartridge tray is slightly pulled out from the installed state, and (f) is a cross-sectional view showing the positioning shaft and positioning groove when the cartridge tray is further pulled out from (e). [Figure 12] Front view showing the ribs on the cartridge tray. [Figure 13] View from arrow AA in Figure 9 [Figure 14] (a) is a front perspective view showing the process cartridge and cartridge tray with the front door closed, and (b) is a front perspective view showing the process cartridge and cartridge tray with the front door open. [Figure 15] (a) is a rear perspective view showing the process cartridge and cartridge tray with the front door closed, and (b) is a rear perspective view showing the process cartridge and cartridge tray with the front door open. [Figure 16](a) is a side view showing the process cartridge and the cartridge tray with the front door closed, (b) is a side view showing the process cartridge and the cartridge tray with the front door open, and (c) is a side view showing the process cartridge and the cartridge tray with the front door open. [Figure 17] View of the cartridge tray pulled out [Figure 18] View showing the pressing state and the contact state of the contacts on the left side of the process cartridge [Figure 19] View showing the pressing state on the right side of the process cartridge [Figure 20] View showing the positional relationship between the power supply contact portion to the charging roller and the photosensitive drum, etc.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, with reference to the drawings, embodiments for carrying out this invention will be exemplarily and specifically described based on examples. However, dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, the scope of this invention is not intended to be limited to the following embodiments.

[0009] <<First Embodiment>> [Overall Configuration] First, the printer 100 as an image forming apparatus according to the first embodiment is a full-color laser beam printer using the electrophotographic method As shown in FIG. 1, the printer 100 has a device main body 100A and a front door 31 that is supported by the device main body 100A so as to be openable and closable. Regarding the description of the printer 100, the directions are defined as follows. That is, the side where the front door 31 of the printer 100 is provided is the front side (or the front face side), the opposite side is the rear side (or the back face side), and the direction from the rear side to the front side and the direction from the front side to the rear side are the front-rear direction.

[0010] Furthermore, the left side (or non-driven side) and right side (or driven side), as well as the top and bottom sides, are defined based on the printer 100 as viewed from the front. The direction from right to left and from left to right are defined as the left-right direction, and the direction from bottom to top and from top to bottom are defined as the up-down direction.

[0011] As shown in Figure 2, the printer 100 includes an image forming unit 10 for forming an image on a sheet S, a sheet feeding unit 18, a fixing device 23, a pair of discharge rollers 24, and a control unit 200. The printer 100 can form a full-color image or a monochrome image on a sheet-shaped recording medium (hereinafter referred to as sheet S) based on an electrical image signal output from an external host device 400 and input to the control unit 200 via an interface unit 300. The external host device 400 is, for example, a personal computer, an image reader, and a facsimile machine.

[0012] The control unit 200 is a control means that controls the electrophotographic image formation process of the printer 100, and exchanges various electrical information with the external host device 400. It also handles the processing of electrical information input from various process equipment and sensors, the processing of command signals to various process equipment, predetermined initial sequence control, predetermined image formation process sequence control, and so on.

[0013] The sheet feeding unit 18 is located at the bottom of the printer 100 and includes a cassette 19 for containing the sheets S, a middle plate 21 for supporting the sheets S so that they can be raised and lowered, a pickup roller 20a, and a pair of separation rollers 20b. The cassette 19 is configured to be able to be pulled out and attached to the main body 100A from the front. The sheets S loaded on the middle plate 21 are fed by the pickup roller 20a and separated one by one by the pair of separation rollers 20b. The pair of separation rollers 20b can be configured using a torque limiter or retard roller method, and a separation pad may be used in place of one of the rollers of the pair of separation rollers 20b.

[0014] The fixing device 23 includes a fixing film 23a heated by a heater and a pressure roller 23b that presses against the fixing film 23a, and a fixing nip Q is formed by the fixing film 23a and the pressure roller 23b. The discharge roller pair 24 includes a discharge drive roller 24a and a discharge driven roller 24b that rotates in accordance with the discharge drive roller 24a.

[0015] The image forming unit 10 includes a cartridge tray 40, four process cartridges (cartridges) PPY, PPM, PPC, and PPK, a scanner unit 11, a transfer unit 12, and a cleaning unit 26. The transfer unit 12 includes a drive roller 14, an auxiliary roller 15, a tension roller 16, and an intermediate transfer belt 13. The intermediate transfer belt 13 is stretched over the drive roller 14, the auxiliary roller 15, and the tension roller 16, and is made of a dielectric material and is flexible. The printer 100 is configured to perform image forming operations using process cartridges PPY, PPM, PPC, and PPK that are detachable from the main unit 100A.

[0016] Inside the intermediate transfer belt 13 are primary transfer rollers 17Y, 17M, 17C, and 17K, which face the photosensitive drums of process cartridges PPY, PPM, PPC, and PPK. On the opposite side of the drive roller 14, across the intermediate transfer belt 13, are secondary transfer rollers 27 A secondary transfer nip T2 is formed by the intermediate transfer belt 13 and the secondary transfer roller 27.

[0017] The four process cartridges PPY, PPM, PPC, and PPK each form toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K), respectively. The four process cartridges PPY, PPM, PPC, and PPK are identical in configuration except for the colors of the images they form (the colors of the toners they contain). Therefore, the configuration and image formation process of one of the four process cartridges PPY, PPM, PPC, or PPK will be explained, and the explanations for the others will be omitted. Furthermore, when there is no need to distinguish between the process cartridges PPY, PPM, PPC, and PPK, they may simply be referred to as process cartridge PP.

[0018] As shown in Figures 2 and 3, the process cartridge PPY is a unit in which a drum unit OP and a developing unit DP are integrated. The drum unit OP has a photosensitive drum 1 as an image carrier, and the developing unit DP has a developing roller 3 that develops the latent image formed on the photosensitive drum 1 as a toner image, and a storage section 3b for storing the developer. On the drive side (right side) in the longitudinal direction of the photosensitive drum 1 and the developing roller 3, a drum coupling (drive transmission member, first drive transmission member) 1c and a developing coupling (drive transmission member, second drive transmission member) 3c are provided, respectively. Drive is transmitted from a drive source (not shown) of the main body 100A to the drum coupling 1c and the developing coupling 3c, causing the photosensitive drum 1 and the developing roller 3 to rotate.

[0019] Furthermore, a cartridge developing contact 2 is provided on the non-driven side (left side) in the longitudinal direction of the developing roller 3. The cartridge developing contact 2 is in contact with the main body developing contact 38 (see Figure 20(b)), which will be described later and is provided on the main body 100A, when the developing bias is applied. On the non-driven side in the longitudinal direction of the photosensitive drum 1, an earthing member (cartridge contact, cartridge electrode) 1b is provided to connect the photosensitive drum 1 to ground potential.

[0020] As shown in Figure 3, along the longitudinal direction of the process cartridge PPY, a drum bearing (drive-side support member, first end support member) 1aR is provided at the drive-side end (first end) of the process cartridge PPY. On the opposite side of the drive-side end, the non-drive-side end (second end) of the process cartridge PPY is provided a drum bearing (non-drive-side support member, second end support member) 1aL. The drum bearings 1aR and 1aL support the photosensitive drum 1.

[0021] The longitudinal direction of the process cartridge PPY is the same as the rotation axis direction (longitudinal direction) of the photosensitive drum 1 and the rotation axis direction (longitudinal direction) of the developing roller 3. Furthermore, in the following description, when describing the main unit 100A and the cartridge tray 40, the longitudinal direction of the process cartridge PPY refers to the longitudinal direction of the process cartridge PPY when it is mounted on the mounting section 40a described later. In this embodiment, the longitudinal direction of the process cartridge PPY is perpendicular to the direction of movement of the cartridge tray 40 and the mounting direction of the process cartridge PP.

[0022] The process cartridges PPY, PPM, PPC, and PPK, as multiple cartridges, are removably mounted on a cartridge tray (tray unit, movable member, movable unit) 40. As described above, the cartridge tray 40 is configured to be movable relative to the device body 100A between an internal position located inside the device body 100A and an external position located outside the device body 100A, while supporting the process cartridges PPY, PPM, PPC, and PPK. In this embodiment, when the cartridge tray 40 is in the internal position, the process cartridges PPY, PPM, PPC, and PPK are in the image forming position. It is positioned to perform image forming operations. When the cartridge tray 40 is in the external position, the process cartridges PPY, PPM, PPC, and PPK are in the attachment / detachment position and can be attached to and detached from the cartridge tray 40.

[0023] The printer 100 is equipped with a front door (opening / closing member) 31 attached to the main body 100A. The front door 31 is movable between a closed position that covers the cartridge tray 40 located inside and an open position that exposes the cartridge tray 40 located inside. When the user opens the front door 31, the cartridge tray 40 is exposed, and the user can access the cartridge tray 40. The user can then pull the cartridge tray 40 forward to position each process cartridge PPY, PPM, PPC, and PPK in the attachment / detachment position and replace each process cartridge PPY, PPM, PPC, and PPK.

[0024] [Image Formation Process] Next, the image forming operation of the printer 100 configured in this way will be described. When the control unit 200 of the printer 100 receives a job signal from the interface unit 300, a development separation mechanism (not shown) provided in the main body 100A of the device moves in the front-back direction. The development separation mechanism causes the development roller 3 to come into contact with the photosensitive drum 1.

[0025] In jobs that form monochrome images, only the photosensitive drum of process cartridge PPK contacts the developing roller, while in jobs that form full-color images, the photosensitive drums of process cartridges PPY, PPM, PPC, and PPK contact their respective developing rollers. Each photosensitive drum, each developing roller, and the intermediate transfer belt 13 are driven by a drive source (not shown).

[0026] The scanner unit 11 irradiates the photosensitive drum 1 of the process cartridge PPY with laser light corresponding to the image signal. At this time, the surface of the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by a charging member (charging roller) 5, and an electrostatic latent image is formed on the surface when laser light is irradiated from the scanner unit 11. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing roller 3, and a yellow (Y) toner image is formed on the photosensitive drum 1.

[0027] Furthermore, the cartridge tray 40 is provided with a light guide 57 (see Figure 5(b)) as a pre-exposure means. The light guide 57 is molded from, for example, transparent acrylic. Before the surface of the photosensitive drum 1 is charged by the charging roller 5, light is emitted from a light source (not shown), and this light is uniformly dispersed in the longitudinal direction by the light guide 57 and irradiated onto the surface of the photosensitive drum 1. As a result, the potential of the surface of the photosensitive drum 1 is stabilized, and a good toner image can be formed.

[0028] Similarly, laser light from the scanner unit 11 is shone onto each photosensitive drum of the process cartridges PPM, PPC, and PPK, forming magenta (M), cyan (C), and black (K) toner images on each photosensitive drum. The toner images of each color formed on each photosensitive drum are transferred to the intermediate transfer belt 13 by a primary transfer bias applied to the primary transfer rollers 17Y, 17M, 17C, and 17K. The full-color toner images transferred to the intermediate transfer belt 13 are transported to the secondary transfer nip T2 by the intermediate transfer belt 13, which is rotated by the drive roller 14. The image formation process for each color is performed at a timing that overlaps with the upstream toner image that has been primary transferred onto the intermediate transfer belt 13.

[0029] In parallel with this image formation process, the sheet S fed by the sheet feeding unit 18 is corrected for skew by the registration roller pair 22. Further registration The roller pair 22 transports the sheet S toward the secondary transfer roller 27 in accordance with the toner image conveyed by the intermediate transfer belt 13. The sheet S has the full-color toner image from the intermediate transfer belt 13 transferred to it at the secondary transfer nip T2 by the secondary transfer bias applied to the secondary transfer roller 27. After the toner image transfer, the toner remaining on the surface of the intermediate transfer belt 13 is removed by the cleaning unit 26 and collected in a waste toner collection container (not shown).

[0030] The sheet S onto which the toner image has been transferred is subjected to predetermined heat and pressure at the fixing nip Q of the fixing device 23, causing the toner to melt and then solidify, thereby fixing the image to the sheet S. The sheet S that has passed through the fixing device 23 is discharged to the discharge tray 25 by the discharge roller pair 24.

[0031] [Cartridge tray] Next, the configuration of the cartridge tray 40 will be described. As shown in Figures 4(a) and 4(b), the cartridge tray 40 has tray side plates 41L and 41R arranged with a gap between them in the left-right direction, connecting members 42, 43, 44, 45, and 46 that connect the tray side plates 41L and 41R, and guide members 47L and 47R. In the following description, members provided in pairs on the left and right sides will be distinguished from left and right by adding "L" or "R" to the end of their reference numerals.

[0032] The process cartridges PPY, PPM, PPC, and PPK are supported by tray side plates 41L and 41R. A mounting section 40a is formed between the tray side plate (drive side plate, first side plate) 41R and the tray side plate (non-drive side plate, second side plate) 41L, into which the process cartridges PPY, PPM, PPC, and PPK are mounted. The process cartridge PPY is mounted in mounting section 40aY, the process cartridge PPM is mounted in mounting section 40aM, the process cartridge PPC is mounted in mounting section 40aC, and the process cartridge PPK is mounted in mounting section 40aK. The process cartridges PPY, PPM, PPC, and PPK are mounted in mounting sections 40aY, 40aM, 40aC, and 40aK along the mounting direction (arrow In direction).

[0033] The connecting members 42, 43, 44, 45, and 46 are made of resin material and are arranged in order from front to rear. The connecting members 42, 43, 44, and 45 are each provided with the light guides 57 described above. The tray side plates 41L and 41R are made of metal material. The guide member (drive-side cover member, first cover member) 47R is supported by the tray side plate 41R, and the guide member (non-drive-side cover member, second cover member) 47L is supported by the tray side plate 41L. The guide member 47R has a guide groove (first guided groove) 47aR, and the guide member 47L has a guide groove (second guided groove) 47aL. The guide grooves 47aL and 47aR extend along the direction in which the multiple cartridges are arranged and guide the cartridge tray 40 in the pull-out direction and the insertion direction relative to the device body 100A. Furthermore, the guide grooves 47aL and 47aR engage with a stopper (not shown) provided on the main body 100A of the device, thereby restricting the cartridge tray 40 from being pulled out beyond a predetermined position.

[0034] The connecting member 42 has receiving portions 42b, 42b and a gripping portion 42d, and the cartridge tray 40 can be pulled out from the main body 100A by the user gripping and pulling out the gripping portion 42d. In addition, the receiving portions 42b, 42b prevent damage to the internal components of the printer 100 by contacting the front door 31 when the printer 100 is subjected to a forward impact while the front door 31 is closed. Similarly, the connecting member 46 has receiving portions 46a, 46a, and the receiving portions 46a, 46a prevent damage to the internal components of the printer 100 by contacting the fixing stay 35 (see Figure 6) when the printer 100 is subjected to a rearward impact.

[0035] The tray side panels 41L and 41R have a shape where the upper part is tapered outward compared to the lower part, and the distance between the tray side panels 41L and 41R in the left-right direction is wider at the top and narrower at the bottom. This allows the left-right width of the cartridge tray 40 to be reduced without compromising the insertion and removal of process cartridges PPY, PPM, PPC, and PPK, contributing to the miniaturization of the printer 100.

[0036] Furthermore, the tray side panels 41L and 41R are bent into an L-shape at the bottom to ensure strength. The tray side panels 41L and 41R and the connecting members 42, 43, 44, 45, and 46 are fastened with screws, but this is not the only method; heat riveting or other methods may also be used. Alternatively, only the connecting members 42 and 46 may be fastened to the tray side panels 41L and 41R, while the connecting members 43, 44, and 45 do not need to be fastened to the tray side panels 41L and 41R.

[0037] As shown in Figures 4(a) to 5(b), the tray side plate 41R is provided with cartridge engagement portions (first positioning portions) 41gR, 41hR, 41iR, and 41jR, and each of the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR is formed in a roughly V-shape. Specifically, the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR are formed such that the front slope is 65° and the rear slope is 45° with respect to the pulling direction.

[0038] As shown in Figure 4(a), the tray side plate 41L is provided with cartridge engagement portions (second positioning portions) 41gL, 41hL, 41iL, and 41jL, and each of the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL is formed in a roughly V-shape. Specifically, the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL are formed such that the front slope is 65° and the rear slope is 45° with respect to the pulling direction.

[0039] The process cartridges PPY, PPM, PPC, and PPK are positioned by the cartridge tray 40 at the image forming position where the image forming operation is performed. During the image forming operation, the drum bearing 1aR of the process cartridge PPY (see Figure 3(a)) contacts the cartridge engagement portion 41gR, and the drum bearing 1aL of the process cartridge PPY (see Figure 3(b)) contacts the cartridge engagement portion 41gL. Similarly, the drum bearing 1aR of the process cartridges PPM, PPC, and PPK contacts the cartridge engagement portions 41hR, 41iR, and 41jR. In addition, the drum bearing 1aL of the process cartridges PPM, PPC, and PPK contacts the cartridge engagement portions 41hL, 41iL, and 41jL. In other words, the cartridge engagement portions 41gR and 41gL contact and support the drum bearings 1aR and 1aL of the process cartridge PPY so that the process cartridge PPY is positioned at the image forming position. Similarly, the cartridge engagement portions 41hR, 41iR, 41jR and 41hL, 41iL, 41jL contact and support the drum bearings 1aR and 1aL of the process cartridges PPM, PPC, and PPK.

[0040] The process cartridges PPY, PPM, PPC, and PPK are positioned relative to the cartridge tray 40 by their own weight or by being pressed downward by the pressing units 33 and 34 (first pressing member 34, second pressing member 33) (Figures 14 to 20). The pressing units 33 and 34 press each process cartridge downward during image formation, thereby positioning each process cartridge and the cartridge tray 40, which is integrated with each process cartridge, on the device body 100A. As will be described in more detail later, the pressing units 33 and 34 are assembled to the device body 100A so as to be movable between a pressing position that presses each process cartridge and a separation position that separates them, in conjunction with the opening and closing operation of the front door 31 of the printer 100.

[0041] Furthermore, the connecting members 42, 43, 44, and 45 each have boss portions 42aL, 43aL, 44aL, and 45aL formed on their left ends, and boss portions 42aR, 43aR, 44aR, and 45aR formed on their right ends. Each color of process cartridge has groove portions 1dR and 1dL formed on its left and right ends, as shown in Figures 3(a) and (b). The groove portions 1dR and 1dL of each process cartridge PPY, PPM, PPC, and PPK engage with the boss portions 42aL, 43aL, 44aL, and 45aL on the left end and with the boss portions 42aR, 43aR, 44aR, and 45aR on the right end. This prevents each process cartridge PPY, PPM, PPC, and PPK from rotating relative to the cartridge tray 40.

[0042] In this way, the process cartridges PPY, PPM, PPC, and PPK are mounted on the cartridge tray 40, and each process cartridge is grounded via a wire (drum ground) 48 provided on the guide member 47L.

[0043] [Cartridge tray details] Figures 6(a), 6(b), 7(a), 7(b), and 8 will be used to describe the details of the cartridge tray 40. Figures 6(a) and 6(b) are side views showing the drive side of the cartridge tray 40. Figures 6(a) and 6(b) show the cartridge tray 40 along the longitudinal direction of the process cartridge PPY, and the guide member 47R is not shown in Figure 6(b). Figures 7(a) and 7(b) are side views showing the non-drive side of the cartridge tray 40. Figures 7(a) and 7(b) show the cartridge tray 40 along the longitudinal direction of the process cartridge PPY, and the guide member 47L is not shown in Figure 7(b). Figure 8 is a top view of the cartridge tray 40. Figure 8 shows the cartridge tray 40 along the mounting direction In of the process cartridges PPY, PPM, PPC, and PPK.

[0044] As shown in Figure 6(b), the tray side plate 41R comprises a first support portion 41R1 having cartridge engaging portions 41gR, 41hR, 41iR, and 41jR, a first outer portion 41R2, and a first connecting portion 41R3 connecting the first support portion 41R1 and the first outer portion 41R2. The tray side plate 41R is made of metal. In this embodiment, the tray side plate 41R is a single metal plate and integrally comprises the first support portion 41R1, the first outer portion 41R2, and the first connecting portion 41R3. The first support portion 41R1 and the first outer portion 41R2 extend along the direction of movement in which the cartridge tray 40 moves relative to the device body 100A.

[0045] The tray side plate 41R is formed by drawing a metal sheet. As a result, the first connecting portion 41R3 has a portion located horizontally between the first support portion 41R1 and the first outer portion 41R2 when viewed in the longitudinal direction of the process cartridge PPY, and a portion located vertically between the first support portion 41R1 and the first outer portion 41R2. Furthermore, the tray side plate 41R is provided with a first opening 41R5. Cartridge engaging portions 41gR, 41hR, 41iR, and 41jR are formed in the first opening 41R5. In the vertical direction, the upper end of the first opening 41R5 is located above the lower end of the first outer portion 41R2, and the lower end of the first opening 41R5 is located below the upper end of the first support portion 41R1 and the first connecting portion 41R3. The process cartridges PPY, PPM, PPC, and PPK are exposed to the outside of the mounting section 40a through the first opening 41R5. More specifically, the drum couplings 1c of the process cartridges PPY, PPM, PPC, and PPK are exposed to the outside of the cartridge tray 40 through the first opening 41R5.

[0046] As shown in Figure 6(a), the cartridge tray 40 has a guide member (first cover member) 47R attached to the tray side plate 41R outside the mounting portion 40a. The guide member 47R covers the first support portion 41R1. More specifically, the guide member 47R is The first support portion 41R1 is covered such that, when viewed in the longitudinal direction of the process cartridge PPY, the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR are exposed.

[0047] Furthermore, as described above, the guide member 47R is equipped with a guide groove (first guided groove) 47aR. With respect to the mounting direction In of the process cartridges PPY, PPM, PPC, and PPK, the guide groove 47aR is located downstream of the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR. The guide groove 47aR extends along the direction in which the process cartridges PPY, PPM, PPC, and PPK are aligned. As a result, the cartridge tray 40 is movable relative to the main body 100A along the direction in which the process cartridges PPY, PPM, PPC, and PPK are aligned.

[0048] As shown in Figure 7(b), the tray side plate 41L includes a second support portion 41L1 having cartridge engaging portions 41gL, 41hL, 41iL, and 41jL, a second outer portion 41L2, and a second connecting portion 41L3 connecting the second support portion 41L1 and the second outer portion 41L2. The tray side plate 41L is made of metal. In this embodiment, the tray side plate 41L is a single metal plate and integrally includes the second support portion 41L1, the second outer portion 41L2, and the second connecting portion 41L3. The second support portion 41L1 and the second outer portion 41L2 extend along the direction of movement in which the cartridge tray 40 moves relative to the device body 100A.

[0049] The tray side plate 41L is formed by drawing a metal sheet. As a result, the second connecting portion 41L3 has a portion located horizontally between the second support portion 41L1 and the second outer portion 41L2 when viewed in the longitudinal direction of the process cartridge PPY, and a portion located vertically between the second support portion 41L1 and the second outer portion 41L2. Furthermore, the tray side plate 41L is provided with a second opening (contact opening) 41L5. Cartridge engaging portions 41gL, 41hL, 41iL, and 41jL are formed in the second opening 41L5. In the vertical direction, the upper end of the second opening 41L5 is located above the lower end of the second outer portion 41L2, and the lower end of the second opening 41L5 is located below the upper end of the second support portion 41L1 and the second connecting portion 41L3. The process cartridges PPY, PPM, PPC, and PPK are exposed to the outside of the mounting section 40a through the second opening 41L5. More specifically, the grounding member 1b of the process cartridges PPY, PPM, PPC, and PPK is exposed to the outside of the mounting section 40a through the second opening 41L5.

[0050] As shown in Figure 7(a), the cartridge tray 40 has a guide member (second cover member) 47L attached to the tray side plate 41L outside the mounting portion 40a. The guide member 47L covers the second support portion 41L1. More specifically, the guide member 47L covers the second support portion 41L1 such that at least a portion of the second opening 41L5 is covered when viewed in the longitudinal direction of the process cartridge PPY. The guide member 47L is also provided with a wire 48. When viewed in the longitudinal direction of the process cartridge PPY, the wire 48 is positioned to overlap with the second opening 41L5.

[0051] Furthermore, as described above, the guide member 47L is equipped with a guide groove (second guided groove) 47aL. With respect to the mounting direction In of the process cartridges PPY, PPM, PPC, and PPK, the guide groove 47aL is located downstream of the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL. The guide groove 47aL extends along the direction in which the process cartridges PPY, PPM, PPC, and PPK are aligned. As a result, the cartridge tray 40 is movable relative to the device body 100A along the direction in which the process cartridges PPY, PPM, PPC, and PPK are aligned.

[0052] As shown in Figure 8, when viewed in the mounting direction In, the process car mounted on the mounting portion 40a In the longitudinal direction of the PP cartridge (arrow LD), the first support portion 41R1 and the second support portion 41L1 are located between the first outer portion 41R2 and the second outer portion 41L2. Also, when viewed in the mounting direction In, the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR are exposed on the upstream side (front side of the paper) in the mounting direction In through the first opening 41R5. Similarly, the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL are exposed on the upstream side (front side of the paper) in the mounting direction In through the second opening 41L5.

[0053] [Cartridge tray positioning configuration] Next, the positioning configuration of the cartridge tray 40 will be described. The main body 100A (see Figure 1) has a main body frame 30 which includes a pair of left and right main body side plates 36L and 36R, and a fixing stay 35 which connects the main body side plates 36L and 36R and separates the process area from the fixing area, as shown in Figure 9. The process area is the area in which the process cartridges PPY, PPM, PPC, and PPK are housed, and the fixing area is the area in which the fixing device 23 is housed. The main body side plates 36L and 36R and the fixing stay 35 are made of metal material.

[0054] The main body side plates 36L and 36R each have pivot supports 50aL and 50aR on the rear side of the device, and a positioning shaft 50 is supported on these pivot supports 50aL and 50aR. The positioning shaft 50 is fixed to the pivot supports 50aL and 50aR so as not to move, but it may be supported so as to be rotatable, as long as it is not movable in the front-to-back and up-to-down directions.

[0055] Furthermore, the main body side plates 36L and 36R have positioning grooves 36aL and 36aR, respectively, on the front side of the device. As shown in Figure 10, pivot supports 41dL and 41dR are formed on the front side of the tray side plates 41L and 41R of the cartridge tray 40, respectively. A positioning shaft 49 is supported by the pivot supports 41dL and 41dR. The positioning shaft 49 penetrates the tray side plates 41L and 41R, and the left end 49a and the right end (not shown) of the positioning shaft 49 protrude to the outside of the tray side plates 41L and 41R. The positioning shaft 49 is fixed immovably to the pivot supports 41dL and 41dR, but it may be rotatably supported as long as it is immovable in the front-rear and up-down directions. The positioning shafts 49 and 50 are composed of round rod-shaped shafts with a circular cross-section that extend in the left-right direction, but their shape is not limited.

[0056] Furthermore, the connecting member 42 has an axial contact portion 42c formed thereon that supports the approximate center of the positioning shaft 49 in the axial direction, and the axial contact portion 42c restricts the downward deflection of the positioning shaft 49. Note that the axial contact portion 42c is not limited to the approximate center of the positioning shaft 49 in the axial direction, but may support other positions of the positioning shaft 49, however, it is preferable to restrict the downward deflection of the positioning shaft 49 at its center. In addition, the axial contact portion 42c may be formed to be long in the axial direction.

[0057] As shown in Figure 11(d), the positioning groove 36aR of the main body side plate 36R is formed along the insertion direction Y1 of the cartridge tray 40 and has a fitting groove 37aR formed on the rear side and a guide groove 37bR formed on the front side.

[0058] The fitting groove 37aR has a width equal to or slightly smaller than the outer diameter of the positioning shaft 49, and fits onto the end 49a of the positioning shaft 49 when the cartridge tray 40 is in the mounting position. The guide groove 37bR has a width greater than the outer diameter of the positioning shaft 49, and guides the end 49a of the positioning shaft 49 into the fitting groove 37aR when the cartridge tray 40 is mounted on the device body 100A. The guide groove and fitting groove are similarly formed on the main body side plate 36L, and guide or engage with the left end of the positioning shaft 49.

[0059] As shown in Figure 5(b), the tray side plates 41L and 41R each have positioning grooves on the rear side. Positioning grooves 41bL and 41bR are formed, and the cartridge tray 40 is positioned by engaging with the positioning shaft 49. Figures 11(a) to 11(c) are enlarged views showing the positioning groove 41bL. Since the positioning grooves 41bL and 41bR have similar configurations, only the positioning groove 41bR will be described, and the description of the positioning groove 41bL will be omitted.

[0060] As shown in Figures 11(a) to 11(c), the positioning groove 41bR has an inclined surface 41f and a positioning surface 41e that is formed continuously with the inclined surface 41f. The positioning surface 41e extends in a direction substantially perpendicular to the insertion direction Y1 of the cartridge tray 40 and positions the cartridge tray 40 in the insertion direction by abutting against the positioning shaft 50. The inclined surface 41f is inclined downward as it approaches the insertion direction Y1. In addition, the connecting member 46 of the cartridge tray 40 has a sliding surface 46d (see Figure 5(b)) formed thereon, and the sliding surface 46d is formed to be continuous with the inclined surface 41f on the front side.

[0061] As shown in Figure 11(a), when the cartridge tray 40 is installed, the inclined surface 41f receives a reaction force F1 from the positioning shaft 50 due to the weight of the cartridge tray 40 and the downward force applied by the pressing units 33, 34 (see Figure 14(a)). Since the reaction force F1 has a component force in the insertion direction Y1, the cartridge tray 40 is pulled in the insertion direction Y1 and moves in the direction of F2. As a result, the positioning surface 41e is pressed against the positioning shaft 50, and the cartridge tray 40 can be accurately positioned relative to the device body 100A. In this way, the inclined surface 41f is formed to generate a component force.

[0062] As shown in Figure 12, the positioning shaft 50 is supported by the pivot points 50aL and 50aR of the main body side plates 36L and 36R. When the cartridge tray 40 is mounted on the device body 100A, the positioning grooves 41bL and 41bR are located axially inward from the pivot points 50aL and 50aR. As a result, the central part of the positioning shaft 50 is subjected to a downward force due to the weight of the cartridge tray 40 and the pressing units 33 and 34 (see Figure 14(a)), and there is a risk that it will bend downward (in the direction of the white arrow in the figure).

[0063] Therefore, in this embodiment, a rib 46b is formed approximately in the center of the connecting member 46 in the axial direction (left-right direction). The rib 46b contacts and supports the positioning shaft 50 approximately in the axial direction, thereby restricting the downward deflection of the positioning shaft 50. Note that the rib 46b is not limited to the approximately center of the positioning shaft 50 in the axial direction, but may support other positions of the positioning shaft 50, however, restricting the downward deflection of the positioning shaft 50 at its center is preferable. Furthermore, the rib 46b may be formed to be long in the axial direction, or multiple ribs 46b may be provided in the axial direction. In addition, in this embodiment, the downward deflection of the positioning shaft 50 is restricted because it is subjected to a force in the direction of gravity, but if the deflection of the positioning shaft 50 is restricted by receiving a force in the direction of deflection of the positioning shaft 50, it is not necessary for the rib 46b to contact the lower part of the positioning shaft 50.

[0064] Furthermore, as shown in Figures 12 and 13, the connecting member 46 has locking portions 46c, 46c formed thereon that can be locked onto the fixing stay 35. By locking the locking portions 46c, 46c onto the fixing stay 35, the downward deflection of the cartridge tray 40 including the connecting member 46 can be restricted. By suppressing the downward deflection of the cartridge tray 40, deformation in the positioning grooves 41bL, 41bR of the cartridge tray 40 is also suppressed, and the cartridge tray 40 can be positioned accurately with respect to the positioning axis 50. Note that the locking portions 46c, 46c do not hinder the mounting operation of the cartridge tray 40, and may be provided as one or as three or more. Also, one locking portion 46c may be formed to be long in the axial direction (left-right direction).

[0065] [Cartridge tray removal and insertion operation] Next, we will explain the operation of pulling out and inserting the cartridge tray 40. Each process cartridge (PPY, PPM, PPC, PPK) loses its commercial value as a process cartridge when the developer is consumed to such an extent that it can no longer produce images of satisfactory quality for the user who purchased it.

[0066] For example, the control unit 200 may be equipped with means (not shown) for detecting the remaining amount of developer in each process cartridge, and compare the detected remaining amount with a preset threshold for cartridge life prediction or life warning. When the detected remaining amount of a process cartridge falls below the threshold, the display unit (not shown) displays a life prediction or life warning for that process cartridge, prompting the user to replace the process cartridge. The user then opens the front door 31 of the printer 100, pulls out the cartridge tray 40 from the device, and replaces each process cartridge PPY, PPM, PPC, and PPK. The following describes in detail the operation of pulling out and installing the cartridge tray 40.

[0067] As shown in Figures 14(a) to 15(b), the front door 31 is supported by the main body 100A so as to be openable and closable, and can be held open by door links 32L and 32R connected between the front door 31 and the main body 100A.

[0068] When the front door 31 is opened by the user, several link members (not shown) are linked via door links 32L and 32R, causing the transfer unit 12 to rotate about 1° around the drive roller 14. As a result, the photosensitive drum 1 of each process cartridge is separated from the intermediate transfer belt 13, as shown in Figure 16(c).

[0069] Next, as shown in Figure 20(b), the main body developing contact 38 located on the left side (non-driven side) of the main body 100A retracts from the cartridge developing contact 2 (see Figure 3(b)) electrically connected to each developing roller 3, and the pressing of the pressing units 33 and 34 is released. That is, the pressing unit 33, as the second pressing member, moves from the second pressing position to the second separation position, and the pressing unit 34, as the first pressing member, moves from the first pressing position to the first separation position. Next, the engagement of the drum coupling 1c and developing coupling 3c (Figure 3(a)) on the drive side of each process cartridge is released, and as shown in Figures 14(b) and 16(b), the pressing of the cartridge tray 40 by the tray pressing unit 51 is released. As a result, the cartridge tray 40 can be removed from the main body 100A.

[0070] Here, the tray pressing unit 51 is provided on holders 52L and 52R, respectively, which are supported by the main body side plates 36L and 36R, and presses the cartridge tray 40 from the rear to the front during image formation. As shown in Figures 16(a) and (b), the tray pressing unit 51 includes a tray pressing lever 53, a tray pressing link 54, and a biasing spring (not shown).

[0071] As shown in Figure 16(a), the tray pressing lever 53 is pressed by a tray pressing link 54, which is biased by a biasing spring, when the front door 31 is closed. As a result, the tray pressing lever 53 presses the pressed portion 41c formed on the tray side plate 41R of the cartridge tray 40 toward the rear.

[0072] When the front door 31 is opened, the tray pressing lever 53 is retracted downward by the door links 32L, 32R and a link member (not shown), as shown in Figure 16(b). This releases the pressure on the rear of the cartridge tray 40 by the tray pressing lever 53, making it possible to remove the cartridge tray 40 from the outside of the device body 100A.

[0073] Next, the movement around the positioning axes 49 and 50 will be explained using Figures 11(a) to 11(f). However, since the positioning configuration of the cartridge tray 40 on the positioning axes 49 and 50 is the same on both the left and right sides, only the right side of the device will be explained, and the explanation for the left side of the device will be omitted. As shown in Figures 11(a) to 11(f), when the cartridge tray 40 begins to be pulled out, the inclined surface 41f slides against the positioning axis 50, causing the back side of the cartridge tray 40 to lift slightly. Then, the cartridge tray 40 moves in the pulling direction Y2 while the sliding surface 46d provided on the connecting member 46 of the cartridge tray 40 slides against the positioning axis 50.

[0074] Simultaneously, the end 49a of the positioning shaft 49 of the cartridge tray 40 disengages from the fitting groove 37aR of the positioning groove 36aR and is transferred to the guide groove 37bR. The cartridge tray 40 is pulled out in the pulling direction Y2, with the end 49a of the positioning shaft 49 guided by the guide groove 37bR. Figures 11(a) and 11(d) show the state in which the cartridge tray 40 is in the mounting position. Figures 11(b) and 11(e) show the state in which the cartridge tray 40 is pulled out about 3 mm from the mounting position. Figures 11(c) and 11(f) show the state in which the cartridge tray 40 is pulled out about 10 mm from the mounting position.

[0075] Once the cartridge tray 40 is pulled out to a certain extent, it is guided on the rollers 56L and 56R (the first and second rotating bodies), as shown in Figures 14(b) and 15(b). The cartridge tray 40 is then pulled out to the outside of the main body 100A of the device. During image formation, the cartridge tray 40 and the rollers 56L and 56R are not in contact, and a clearance of approximately 0.5 mm is maintained.

[0076] Figure 17 shows the process of the cartridge tray being pulled out. The guide groove 47aL of the cartridge tray 40 is guided by a guide portion 32aL provided on the door link 32L. The configuration of the guide groove 47aR and the guide portion 32aR is the same as the configuration of the guide groove 47aL and the guide portion 32aL. Therefore, even when the amount of the cartridge tray 40 is pulled out is large, the tilt of the cartridge tray 40 can be reduced and it can be pulled out smoothly. In addition, the posture of the cartridge tray 40 when it is pulled out can be stabilized, so the ease of replacing process cartridges can be improved.

[0077] The guide grooves 47aL and 47aR are provided on the outside of the first support portion 41R1 and the second support portion 41L1 of the tray side plates 41L and 41R, which are made of metal material, and are formed in a U-shape with the outside open. Below the guide grooves 47aL and 47aR, protrusions 41L4 and 41R4 are arranged, extending outward from the first support portion 41R1 and the second support portion 41L1. The guide grooves 47aL and 47aR are positioned between the outer portions 41L2 and 41R2 and the protrusions 41L4 and 41R4. In the direction in which the process cartridge is mounted onto the cartridge tray 40, the guide groove 47aL is positioned downstream of the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL, and the guide groove 47aR is positioned downstream of the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR. This allows for the construction of a robust guide. When the cartridge tray 40 is pulled out, the protrusions 41L4 and 41R4 are supported by rollers 56L and 56R.

[0078] Furthermore, the guide grooves 47aL and 47aR are located inward from the first outer portion 41R2 and the second outer portion 41L2 in the longitudinal direction of the photosensitive drum 1, allowing them to be arranged without increasing the size of the cartridge tray 40 and the image forming apparatus. The process cartridge can be mounted on the cartridge tray 40 by dropping it through the upward-opening. The tray side plates 41L and 41R have a first support portion 41R1, a second support portion 41L1, and a first outer portion 41R2 and a second outer portion 41L2. The device includes a first connection part 41R3 and a second connection part 41L3. The first connection part 41R3 and the second connection part 41L3 have inclined surfaces that slope from the outside to the inside of the mounting part 40a in the longitudinal direction LD. More specifically, the inclined surfaces of the first connection part 41R3 and the second connection part 41L3 slope from the outside to the inside of the mounting part 40a from the upstream side to the downstream side in the mounting direction of the process cartridge PP. These inclined surfaces allow the process cartridge PP to be smoothly mounted into the cartridge tray 40.

[0079] The installed process cartridge PP is positioned at the cartridge engagement portions 41gL, 41hL, 41iL, 41jL, 41gR, 41hR, 41iR, and 41jR of the tray side plates 41L and 41R. At this time, the ground member 1b, which is a cartridge contact provided at the end of the photosensitive drum 1, is connected to a wire 48, which is a contact member provided on the cartridge tray 40 for each process cartridge PP. The wire 48 acts as a tray contact, serving as an intermediate contact that electrically connects the photosensitive drum 1 and the main body frame 30 of the device body 100A. Each wire 48 is connected to a conductive wire 59 below the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL, and via the conductive wire 59, is connected to the main body side plate 36L of the main body frame 30. In other words, when the cartridge tray 40 is located inside the main body 100A of the device, the grounding member 1b is electrically connected to the main body 100A via the wire 48 and the side plate 41L.

[0080] The wire 48 has an arm portion 48b that acts as a spring portion with spring properties, and a wound portion 48a that is wound along the insertion direction In of the process cartridge PP at the contact point with the ground member 1b. The spring properties of the arm portion 48b bias the wound portion 48a toward the ground member 1b. The ground member 1b and the wound portion 48a come into contact at a position upstream of the cartridge engagement portions 41gL, 41hL, 41iL, 41jL and downstream of the second outer portion 41L2 when the process cartridge is mounted on the cartridge tray 40. On the other hand, the wound portion 48a is roughly positioned by inserting and passing a contact restricting portion 47eL provided on the guide member 47L through the wound portion 48a. This contact restricting portion 47eL restricts the contact position between the ground member 1b and the wound portion 48a to a predetermined position even when the process cartridge is not mounted on the mounting portion 40a. Furthermore, by positioning the wire 48 below the second connection portion 41L3, damage to the wire 48 is prevented when inserting the process cartridge PP into the cartridge tray 40, allowing for smooth insertion of the process cartridge PP. In addition, by positioning the wire 48 inward from the second outer portion 41L2 in the longitudinal direction of the photosensitive drum 1, it was possible to accommodate the cartridge tray 40 and the image forming apparatus without increasing their size.

[0081] The wire 48 is positioned adjacent to the outside of the second support portion 41L1 of the tray side plate 41L in the longitudinal direction of the photosensitive drum 1, and is held in place by a guide member 47L with a guide groove 47aL further outside. The wire 48 is also electrically connected to the tray side plate 41L, which is made of metal, and as described later, the tray side plate 41L is connected to the positioning shafts 49 and 50, and the positioning shafts 49 and 50 are connected to the main frame 30. In this way, a more robust grounding contact path is formed.

[0082] When the cartridge tray 40 is pulled out and the process cartridge is replaced, the cartridge tray 40 is mounted on the main unit 100A of the apparatus. The mounting operation when mounting the cartridge tray 40 on the main unit 100A is the reverse of the pulling operation. At this time, the sliding surface 46d first begins to slide on the positioning shaft 50, and as shown in Figures 11(b) and (e), after the positioning shaft 50 has passed the sliding surface 46d, the end 49a of the positioning shaft 49 is transferred from the guide groove 37bR to the fitting groove 37aR.

[0083] The boundary between the guide groove 37bR and the fitting groove 37aR is sloped upward, and the end portion 49a of the positioning shaft 49 is fitted into the fitting groove 37aR, so the cartridge tray 40 The user's operating force is increased when installing the cartridge. However, since the positioning shaft 49 enters the fitting groove 37aR after the sliding surface 46d has passed the positioning shaft 50, the timing of when the user's operating force is increased is not concentrated, thus reducing the operating force. Furthermore, once the cartridge tray 40 has been inserted to a predetermined distance to the installation position, it is configured to be automatically pulled into the installation position by a retraction device described later.

[0084] Once the cartridge tray 40 is inserted to the mounting position and the front door 31 (opening / closing member) is closed, the tray pressing unit 51 presses the cartridge tray 40 inward, as shown in Figures 14(a), 15(a), and 16(a). Then, the drum coupling 1c and developing coupling 3c (see Figure 3(a)) on the drive side of each process cartridge PP engage, and the pressing units 33 and 34 press each process cartridge PP from above.

[0085] Figures 18 and 19 show the pressing state in which the pressing units 33 and 34 press the process cartridge. Figure 18(a) is a schematic perspective view showing the contact between the main body developing contact 38 and the cartridge developing contact 2 connected to the developing roller 3, and the contact between the pressing part 33a and the memory member 7, partially cut in the longitudinal direction of the photosensitive drum 1 on the left side of the process cartridge PPK. Figure 18(b) is a schematic view of the cross-section of Figure 18(a) as seen in the direction of movement of the cartridge tray 40. Figure 18(c) is a schematic view of the cross-sections of each process cartridge and cartridge tray 40 in the second virtual plane IFL shown in Figure 18(b), as seen in the longitudinal direction of the photosensitive drum 1. Figure 19(a) is a schematic perspective view showing the center of the drum coupling 1c on the right side of the process cartridge PPK as partially cut in the longitudinal direction of the photosensitive drum 1. Figure 19(b) is a schematic view of the cross-section of Figure 19(a) as seen in the direction of movement of the cartridge tray 40. Figure 19(c) is a schematic diagram showing the cross-sections of each process cartridge and cartridge tray 40 in the first virtual plane IFR shown in Figure 19(b), viewed along the longitudinal direction of the photosensitive drum 1.

[0086] Here, the pressing units 33 and 34 press the drum bearings 1aL and 1aR toward the cartridge engagement portions 41gL, 41hL, 41iL, 41jL, 41gR, 41hR, 41iR, and 41jR. The pressing unit 34 (first pressing member) is positioned to intersect with a first virtual plane IFR that is perpendicular to the longitudinal direction of the photosensitive drum 1 and intersects with the cartridge engagement portions 41gR, 41hR, 41iR, and 41jR (first positioning portions). The pressing unit 33 (second pressing member) is positioned to intersect with a second virtual plane IFL that is perpendicular to the longitudinal direction and intersects with the cartridge engagement portions 41gL, 41hL, 41iL, and 41jL (second positioning portions).

[0087] Furthermore, when viewed from the longitudinal direction of the photosensitive drum 1, the contact portion (pressing portion) 39 of the pressing units 33 and 34, which is the part that contacts the cartridge, is positioned so that it overlaps with the cartridge engagement portions 41gL, 41hL, 41iL, 41jL, 41gR, 41hR, 41iR, and 41jR with respect to the pressing direction of the pressing units 33 and 34. In other words, the force with which the pressing units 33 and 34 press the process cartridge is received by the cartridge engagement portions 41gL, 41hL, 41iL, 41jL, 41gR, 41hR, 41iR, and 41jR, which are on the same line. Thus, the process cartridge can be held stably and firmly and positioned.

[0088] Furthermore, the pivot support portions 41dL, 41dR and positioning grooves 41bL, 41bR of the tray side plates 41L, 41R are provided on the same plane as the cartridge engagement portions 41gL, 41hL, 41iL, 41jL, 41gR, 41hR, 41iR, 41jR, and are supported by the positioning shafts 49, 50 (Figures 6 and 7). In addition, the pressing portion 33a, which is part of the contact portion 39 of the pressing unit 33, also has contact with a memory member 7 provided in the process cartridge PP for storing various information such as the operation history of the process cartridge and performance information specific to the process cartridge. As described above, the process cartridge is held stably and firmly. By being able to position the device precisely, stable power supply and communication can be maintained.

[0089] Furthermore, as shown in Figure 20, the pressing unit 33 is equipped with a main body charging contact 37 for supplying power to the charging roller 5. The process cartridge PP is equipped with a charging contact 6 electrically connected to the charging roller 5. The main body charging contact 37 is made of a wire having the same configuration as the wire 48 described above, and is configured to be biased against the charging contact 6 by its springiness and to make contact with the charging contact 6. Figure 20 is a diagram showing the positional relationship between the power supply contact part to the charging roller 5 and the photosensitive drum 1 and the charging roller 5, etc. Figure 20(a) is a schematic perspective view showing the contact between the main body charging contact 37 and the charging contact 6 on the left side of the process cartridge PPK, partially cut in the longitudinal direction of the photosensitive drum 1. Figure 20(b) is a schematic view of the cut surface of Figure 20(a) as seen in the direction of movement of the cartridge tray 40. The pressing unit 33 presses the process cartridge PP from above, even in the part where the main body charging contact 37 is provided. The pressing unit 33 presses the process cartridge PP from above and positions the main body's charged contact 37 relative to the charged contact 6 of the process cartridge, thereby connecting the main body's charged contact 37 with the charged contact 6. The main body's charged contact 37 is positioned in the longitudinal direction of the photosensitive drum 1, overlapping with the photosensitive drum 1 and the charged roller 5. That is, the contact position between the main body's charged contact 37 and the charged contact 6 is positioned in the longitudinal direction of the photosensitive drum 1, overlapping with the photosensitive drum 1 and the charged roller 5. Therefore, the pressing unit 33 around the contact area of ​​the main body's charged contact 37 and the charged contact 6 allows for precise positioning of the contact area, the photosensitive drum 1, and the charged roller 5 relative to each other. In other words, by stably and firmly holding and positioning the process cartridge, stable current flow can be maintained. Furthermore, since a strong and stable contact path can be formed near the ends of the photosensitive drum 1 and the charged roller 5, the contact path within the process cartridge can be shortened, and the process cartridge can be manufactured at a low cost. In the longitudinal direction of the photosensitive drum 1, the main body charging contact 37 and charging contact 6 are positioned between the first support portion 41R1 and the second support portion 41L1.

[0090] As described above, after the pressing units 33 and 34 press the process cartridge from above, the main unit developing contact 38 then contacts the cartridge developing contact 2 (see Figure 3(b)) connected to each developing roller 3, and the transfer unit 12 rotates upward around the drive roller 14. As a result, the photosensitive drum 1 of each process cartridge comes into contact with the intermediate transfer belt 13.

[0091] As described above, when the front door 31 is closed and the printer 100 is in an image-forming state, the positioning shaft 50 and the positioning grooves 41bL and 41bR engage with each other on the front side of the cartridge tray 40. At this time, since the positioning grooves 41bL and 41bR are provided with inclined surfaces 41f, the cartridge tray 40 is pulled in the insertion direction Y1 based on the weight of the cartridge tray 40 and the downward force from the pressing units 33 and 34. As a result, the positioning surface 41e is pressed against the positioning shaft 50, and the cartridge tray 40 can be accurately positioned in the insertion direction Y1.

[0092] Furthermore, at the rear of the cartridge tray 40, the positioning shaft 49 engages with the positioning grooves 36aL and 36aR. At this time, the end portion 49a of the positioning shaft 49 fits into the fitting grooves of the positioning grooves 36aL and 36aR, thereby preventing the cartridge tray 40 from rotating in a direction perpendicular to the mounting direction Y1, i.e., around the positioning shaft 50.

[0093] The positioning shaft 50 and positioning grooves 36aL, 36aR provided on the main body 100A of the device, and the positioning grooves 41bL, 41bR and positioning shaft 50 provided on the cartridge tray 40, constitute a positioning mechanism 60 (see Figures 11(a) and 11(d)). The positioning mechanism 60 positions the cartridge tray 40 on the main body 100A of the device.

[0094] Furthermore, the ribs 46b provided on the connecting member 46 of the cartridge tray 40 support the positioning shaft 50 from below, thereby restricting the downward deflection of the positioning shaft 50. In addition, the locking portions 46c, 46c provided on the connecting member 46 suppress deformation of the cartridge tray 40 itself. Moreover, the positioning shaft 50 on the rear side of the cartridge tray 40 is also supported from below by the shaft contact portion 42c, thereby restricting the downward deflection of the positioning shaft 49. With this configuration, the shaft diameters of the positioning shafts 49 and 50 can be reduced, or they can be made from inexpensive resin materials, thereby reducing costs and miniaturizing the device.

[0095] These features allow the cartridge tray 40 to be accurately positioned on the main body 100A in its mounting position. In particular, during image formation, each process cartridge held in the cartridge tray 40 is pressed from above by the pressing units 33 and 34, but this does not affect the positioning accuracy of the cartridge tray 40. Consequently, the positional accuracy of each process cartridge held in the cartridge tray 40, specifically the photosensitive drum 1 and the intermediate transfer belt 13, is improved, enabling the formation of high-quality images.

[0096] Furthermore, the cartridge tray 40 is biased forward in its mounting position due to the action of the inclined surface 41f on the front side of the cartridge tray 40 and the pressure applied by the tray pressing unit 51 on the rear side. This reduces the likelihood of the cartridge tray 40 shifting position due to vibrations during image formation. In addition, by generating pressing forces on both the front and rear of the cartridge tray 40, the pressing force is distributed, allowing the biasing spring of the tray pressing unit 51 to have a smaller elastic force. This makes it possible to miniaturize and reduce the cost of the tray pressing unit 51.

[0097] Furthermore, the positioning shaft 50 and positioning grooves 41bL, 41bR included in the positioning mechanism 60 may be swapped if they are arranged separately on either the device body 100A or the cartridge tray 40. Also, the positioning grooves 36aL, 36aR and positioning shaft 50 included in the positioning mechanism 60 may be swapped if they are arranged separately on either the device body 100A or the cartridge tray 40.

[0098] Furthermore, the positioning shaft 49 does not have to be a continuous shaft that extends along the entire length of the cartridge tray 40 in the left-right direction; it is sufficient to have two protrusions that protrude from both sides of the cartridge tray 40.

[0099] Furthermore, although each process cartridge is formed with the drum unit OP and the developing unit DP as an integrated unit, they may be configured as separate components. For example, the cartridge tray 40 may hold only the drum unit OP, or it may hold only the developing unit DP. [Explanation of symbols]

[0100] 100…Printer, 100A…Device body, PPY, PPM, PPC, PPK…Process cartridge, 40…Cartridge tray, 40a…Mounting part, 41R, 41L…Tray side plate, 41R1…First support part, 41R2…First outer part, …First connection part, 41L1…Second support part, 41L2…Second outer part, 41L3…Second connection part, 41gR, 41hR, 41iR, 41jR, 41gL, 41hL, 41iL, 41jL…Cartridge engagement part, 1b…Grounding member, 48…Wire

Claims

1. An image forming apparatus in which multiple cartridges are removablely mounted, A device body having a main body side plate, a main body side positioning shaft supported by the main body side plate, and a main body side electrostatic contact, A tray unit is configured to be removable and movable relative to the device body, from an external position located outside the device body to an internal position located inside the device body, wherein the plurality of cartridges are detachably mounted, and the tray unit is configured to be movable relative to the device body in an insertion direction, A first tray side plate made of metal, having a plurality of cartridge positioning sections, an inclined surface that slopes downward as it moves downstream in the insertion direction, and a positioning surface, A tray unit having, Equipped with, Each of the plurality of cartridges is a process cartridge having a photosensitive drum, a charging member configured to charge the photosensitive drum, and a cartridge-side charging contact that can contact the main body-side charging contact and is electrically connected to the charging member. The tray unit is configured to position the process cartridge at the image forming position by contacting the process cartridge. Each of the plurality of cartridge positioning units is configured to position the process cartridge at the image forming position by contacting the process cartridge, The position where the main unit-side charging contact and the cartridge-side charging contact come into contact is higher than the position where each of the plurality of cartridge positioning units comes into contact with the process cartridge. With the tray unit in the internal position, the weight of the tray unit acts on the main body positioning shaft, causing the inclined surface to receive a reaction force from the main body positioning shaft, and the reaction force includes a component force directed in the insertion direction such that the positioning surface is pressed against the main body positioning shaft. An image forming apparatus characterized by the following features.

2. The main body side plate has a main body side positioning groove, The tray unit is positioned in the internal position relative to the main body. Having a tray-side positioning shaft that engages with a positioning groove, The image forming apparatus according to feature 1.

3. The image forming apparatus according to claim 2, characterized in that the tray-side positioning shaft penetrates the first tray side plate.

4. The device body includes a pressing member, The image forming apparatus according to any one of claims 1 to 3, characterized in that the pressing member is configured to press the cartridge from above.

5. The device further includes a door attached to the main body of the aforementioned device, The door is movable between a closed position that covers the tray unit located inside and an open position that exposes the tray unit located inside. The image forming apparatus according to claim 4, characterized in that the pressing member moves in conjunction with the opening and closing of the door.

6. The image forming apparatus according to claim 4 or 5, characterized in that the pressing member is provided with the main body side electrostatic contact.

7. The image forming apparatus according to any one of claims 1 to 6, wherein the tray unit further comprises a second tray side plate made of metal and a connecting member connecting the first tray side plate and the second tray side plate, and a mounting portion for mounting the process cartridge is formed between the first tray side plate and the second tray side plate.

8. With respect to the rotation axis direction of the photosensitive drum, the position where the main unit-side charged contact and the cartridge-side charged contact come into contact is between the first tray side plate and the second tray side plate. The image forming apparatus according to feature 7.

9. The process cartridge includes cartridge contacts for connecting the photosensitive drum to ground potential. The tray unit has a tray contact that is electrically connected to the cartridge contact, and the tray contact has a contact portion that contacts the cartridge contact. The first tray side plate integrally comprises a first support portion having the plurality of cartridge positioning portions, a first outer portion, and a first connecting portion connecting the first support portion and the first outer portion. The image forming apparatus according to claim 1, characterized in that, with respect to the rotation axis direction of the photosensitive drum, the contact portion is located between the first support portion and the first outer portion.

10. A device body having a main body side plate, a main body side positioning shaft supported by the main body side plate, and a main body side electrostatic contact, Multiple cartridges, A tray unit is configured to be removable and movable relative to the device body, from an external position located outside the device body to an internal position located inside the device body, wherein the plurality of cartridges are detachably mounted, and the tray unit is configured to be movable relative to the device body in an insertion direction, A first tray side plate made of metal, having a plurality of cartridge positioning sections, an inclined surface that slopes downward as it moves downstream in the insertion direction, and a positioning surface, A tray unit having, Equipped with, Each of the plurality of cartridges includes a photosensitive drum and a mechanism for charging the photosensitive drum. A process cartridge having a charging member configured as such, and a cartridge-side charging contact that can contact the main body-side charging contact and is electrically connected to the charging member, The tray unit is configured to position the process cartridge at the image forming position by contacting the process cartridge. Each of the plurality of cartridge positioning units is configured to position the process cartridge at the image forming position by contacting the process cartridge, The position where the main unit-side charging contact and the cartridge-side charging contact come into contact is higher than the position where each of the plurality of cartridge positioning units comes into contact with the process cartridge. With the tray unit in the internal position, the weight of the tray unit acts on the main body positioning shaft, causing the inclined surface to receive a reaction force from the main body positioning shaft, and the reaction force includes a component force directed in the insertion direction such that the positioning surface is pressed against the main body positioning shaft. An image forming apparatus characterized by the following features.

11. The main body side plate has a main body side positioning groove, The tray unit has a tray-side positioning shaft that engages with the main body-side positioning groove when the tray unit is in the internal position. The image forming apparatus according to feature 10.

12. The image forming apparatus according to claim 11, characterized in that the tray-side positioning shaft penetrates the first tray side plate.

13. The device body includes a pressing member, The image forming apparatus according to any one of claims 10 to 12, characterized in that the pressing member is configured to press the cartridge from above.

14. The device further includes a door attached to the main body of the aforementioned device, The door is movable between a closed position that covers the tray unit located inside and an open position that exposes the tray unit located inside. The image forming apparatus according to claim 13, characterized in that the pressing member moves in conjunction with the opening and closing of the door.

15. The image forming apparatus according to claim 13 or 14, characterized in that the pressing member is provided with the main body side electrostatic contact.

16. The tray unit further comprises a second tray side plate made of metal and a connecting member connecting the first tray side plate and the second tray side plate, and a mounting portion for mounting the process cartridge is formed between the first tray side plate and the second tray side plate. The image forming apparatus according to any one of claims 10 to 15.

17. With respect to the rotation axis direction of the photosensitive drum, the position where the main unit-side charged contact and the cartridge-side charged contact come into contact is between the first tray side plate and the second tray side plate. The image forming apparatus according to feature 16.

18. The process cartridge includes cartridge contacts for connecting the photosensitive drum to ground potential. The tray unit has a tray contact that is electrically connected to the cartridge contact, and the tray contact has a contact portion that contacts the cartridge contact. The first tray side plate has a first support portion having the plurality of cartridge positioning portions, It integrally comprises a first outer portion and a first connecting portion that connects the first support portion and the first outer portion, The image forming apparatus according to claim 10, characterized in that, with respect to the rotation axis direction of the photosensitive drum, the contact portion is located between the first support portion and the first outer portion.

Images