JP7321720B2 - Positioning device and image forming device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device for positioning a drawer with respect to an apparatus main body and an image forming apparatus having the same.

Generally, in image forming apparatuses such as printers, copiers, and multi-function machines, a cartridge system is adopted in which a photosensitive drum and process means acting on the photosensitive drum are integrated into a cartridge, and the cartridge is detachable from the apparatus main body. there is

Conventionally, a color laser printer has been proposed that includes a drum unit in which four drum subunits are supported by a pair of side plates to form a cartridge, and a main body casing to which the drum unit can be attached and detached (see Patent Document 1). The body casing has a reference axis that positions the drum unit in the attached state by abutting against the notch of the drum unit. Further, the notched portion of the drum unit is pressed against the reference shaft by being pressed toward the back side of the apparatus by the pressing mechanism portion.

JP 2007-178657 A

However, the reference shaft described in Japanese Unexamined Patent Application Publication No. 2002-200011 may bend downward due to force acting in the direction of gravity from the notch of the drum unit. If the reference shaft is bent, the positioning accuracy of the drum unit itself is lowered.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a positioning device capable of improving the positioning accuracy of a drawer portion by restricting deformation of a positioning shaft, and an image forming apparatus having the same.

A positioning device according to the present invention includes a positioning shaft, a first side plate having a first shaft supporting portion for supporting the positioning shaft, and a second shaft supporting portion for supporting the positioning shaft. a device main body having a second side plate spaced apart from the first side plate; a drawer portion displaced with respect to the positioning shaft and capable of being withdrawn from and attached to the device main body; wherein the drawer portion is engaged with the positioning shaft in a predetermined direction, and the engaged portion that positions the drawer portion with respect to the device main body at the mounting position contacts the positioning shaft. and a contact portion for restricting deformation of the positioning shaft in the predetermined direction, wherein the engaged portion is positioned between the first side plate and the second side plate in the axial direction when the drawer portion is positioned at the mounting position. It has a first engaged portion and a second engaged portion that are arranged between the two side plates and engage with the positioning shaft, and the contact portion is axially aligned with the first engaged portion. It is characterized in that it is arranged between the second engaged portion .

According to the present invention, the deformation of the positioning shaft can be restricted by the contact portion, and the positioning accuracy of the drawer portion can be improved.

1 is an overall perspective view showing a printer; FIG. 1 is an overall schematic diagram showing the internal configuration of a printer; FIG. (a) is a front perspective view showing the process cartridge, and (b) is a rear perspective view showing the process cartridge. (a) is a front perspective view showing a cartridge tray, and (b) is a rear perspective view showing the cartridge tray. (a) is a front perspective view showing the cartridge tray with each process cartridge installed, and (b) is a rear perspective view showing the cartridge tray with each process cartridge installed. FIG. 2 is a perspective view showing the frame structure of the printer main body; FIG. 4 is a bottom perspective view showing a positioning shaft of the cartridge tray; (a) is a cross-sectional view showing a state in which the positioning shaft on the apparatus main body side is engaged with the positioning groove, and (b) is a cross-sectional view showing the positioning shaft and the positioning groove when the cartridge tray is pulled out slightly from the mounted state. (c) is a cross-sectional view showing the positioning shaft and the positioning groove when the cartridge tray is further pulled out from (b), and (d) is a cross-sectional view showing a state where the positioning shaft on the cartridge tray side is engaged with the positioning groove. (e) is a sectional view showing the positioning shaft and the positioning groove when the cartridge tray is slightly pulled out from the mounted state, and (f) is the positioning shaft and the positioning groove when the cartridge tray is further pulled out from (e). 3 is a cross-sectional view of FIG. FIG. 4 is a front view showing ribs provided on the cartridge tray; AA arrow view of FIG. (a) is a front perspective view showing a process cartridge and a cartridge tray with a front door closed; 4B is a front perspective view showing the process cartridge and the cartridge tray with the front door opened; FIG. (a) is a rear perspective view showing the process cartridge and the cartridge tray with the front door closed. 4B is a rear perspective view showing the process cartridge and the cartridge tray with the front door opened; FIG. (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 opened. (c) is a side view showing the process cartridge and the cartridge tray with the front door opened. 1 is a perspective view of a retracting device according to a first embodiment; FIG. 1 is a perspective view of a retracting device according to a first embodiment; FIG. The figure which looked at the drawing-in apparatus which concerns on 1st Embodiment from upper direction (a), horizontal direction (b), and the downward direction (c). FIG. 4 is an exploded view of an arm and a locking member according to the first embodiment; The figure (a, b) for demonstrating operation|movement of the drawing-in apparatus which concerns on 1st Embodiment. The figure (a, b) for demonstrating operation|movement of the drawing-in apparatus which concerns on 1st Embodiment. The figure (a, b) for demonstrating operation|movement of the drawing-in apparatus which concerns on 1st Embodiment. The figure (a, b) for demonstrating operation|movement of the drawing-in apparatus which concerns on 1st Embodiment. The figure for demonstrating operation|movement of the drawing-in apparatus which concerns on 1st Embodiment. The top view of the drawing-in apparatus which concerns on 2nd Embodiment. The top view of the drawing-in apparatus which concerns on 3rd Embodiment. The top view of the drawing-in apparatus which concerns on 3rd Embodiment. The top view of the drawing-in apparatus which concerns on 3rd Embodiment.

<<First Embodiment>>
[overall structure]
First, a printer 100 as an image forming apparatus according to the first embodiment is an electrophotographic full-color laser beam printer. The printer 100, as shown in FIG. 1, has an apparatus main body 100A and a front door 31 supported to be openable and closable with respect to the apparatus main body 100A. Regarding the description of the printer 100, directions are defined as follows. That is, the side on which the front door 31 of the printer 100 is provided is the front side (or front side), and the opposite side is the rear side (or rear side). is the front-back direction.

Also, the left side (or non-driving side), the right side (or driving side), the upper side and the lower side are defined with reference to the state of the printer 100 viewed from the front side. The right-to-left direction and the left-to-right direction are defined as left-right directions, and the lower-to-upper direction and the upper-to-lower direction are defined as up-down directions.

As shown in FIG. 2, the printer 100 includes an image forming unit 10 that forms an image on a sheet S, a sheet feeding section 18, a fixing device 23, a discharge roller pair 24, and a control section 200. ing. Printer 100 prints a full-color image or image on a sheet-like recording medium (hereinafter referred to as sheet S) based on an electrical image signal that is output from external host device 400 and input to control unit 200 via interface unit 300 . A monochrome image can be formed. The external host device 400 is, for example, a personal computer, an image reader, a facsimile machine, and the like.

The control unit 200 is control means for controlling the electrophotographic image forming process of the printer 100 and exchanges various electrical information with the external host device 400 . It also controls processing of electrical information input from various process equipment and sensors, processing of command signals to various process equipment, predetermined initial sequence control, sequence control of a predetermined image forming process, and the like.

The sheet feeding unit 18 is provided in the lower part of the printer 100, and has a cassette 19 that stores the sheets S, an intermediate plate 21 that supports the sheets S so that they can move up and down, a pickup roller 20a, and a separation roller pair 20b. are doing. The cassette 19 is configured to be able to be pulled out from the front side of the apparatus main body 100A and mounted thereon. Sheets S stacked on the intermediate plate 21 are fed by a pickup roller 20a and separated one by one by a separation roller pair 20b. Note that the separation roller pair 20b can employ a torque limiter system or a retard roller system, and a separation pad may be used instead of one roller of the separation roller pair 20b.

The fixing device 23 has a fixing film 23a heated by a heater and a pressure roller 23b that presses against the fixing film 23a. A fixing nip Q is formed by the fixing film 23a and the pressure roller 23b. The discharge roller pair 24 has a discharge drive roller 24a and a discharge driven roller 24b that rotates following the discharge drive roller 24a.

The image forming unit 10 as an image forming section has a cartridge tray 40 , four process cartridges PPY, PPM, PPC and PPK, a scanner unit 11 , a transfer unit 12 and a cleaning unit 26 . The transfer unit 12 has 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 around a drive roller 14, an auxiliary roller 15, and a tension roller 16, is made of a dielectric material, and has flexibility.

Inside the intermediate transfer belt 13, primary transfer rollers 17Y, 17M, 17C and 17K are provided facing the respective photosensitive drums of the process cartridges PPY, PPM, PPC and PPK. A secondary transfer roller 27 is provided on the opposite side of the drive roller 14 with the intermediate transfer belt 13 interposed therebetween. A secondary transfer nip T2 is formed by the intermediate transfer belt 13 and the secondary transfer roller 27 .

The four process cartridges PPY, PPM, PPC, and PPK form four-color toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. The four process cartridges PPY, PPM, PPC, and PPK have the same configuration except that the colors of the images to be formed are different. Therefore, only the configuration of the process cartridge PPY and the image forming process will be described, and the description of the process cartridges PPM, PPC, and PPK will be omitted.

As shown in FIGS. 2 and 3, the process cartridge PPY is formed by integrating a drum unit OP and a developing unit DP. A drum unit OP as a unit has a photosensitive drum 1 as a photosensitive member capable of carrying a toner image. The developing unit DP as a unit has a developing roller 3 that develops a latent image formed on the photosensitive drum 1 into a toner image, and a storage section 3b that stores developer. A drum coupling 1c and a developing coupling 3c are provided on the driving side (right side) in the longitudinal direction of the photosensitive drum 1 and the developing roller 3, respectively, and drive is transmitted from a drive source (not shown) of the apparatus main body 100A. . A contact 2 is provided on the driven side (left side) in the longitudinal direction of the developing roller 3, and the contact 2 is in contact with a contact 38 (see FIG. 12B) provided on the apparatus main body 100A. A developing bias is applied in this state. A contact 1b for connection to a ground potential is provided on the driven side of the photosensitive drum 1 in the longitudinal direction.

The process cartridges PPY, PPM, PPC, and PPK are held in the cartridge tray 40, and the user can access the cartridge tray 40 by opening the front door 31. FIG. The user can replace the process cartridges PPY, PPM, PPC, and PPK by pulling out the cartridge tray 40 forward.

[Image forming operation]
Next, the image forming operation of the printer 100 configured as described above will be described. When the control unit 200 of the printer 100 receives a job signal from the interface unit 300, a developing separation mechanism (not shown) provided in the apparatus main body 100A moves in the front-rear direction. The development roller 3 is brought into contact with the photosensitive drum 1 by the development separation mechanism.

In a job for forming a monochrome image, only the photosensitive drum of the process cartridge PPK comes into contact with the developing roller. abut. Each photosensitive member, each developing roller, and the intermediate transfer belt 13 are driven by a drive source (not shown).

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

The cartridge tray 40 is provided with a light guide 57 (see FIG. 5B) as pre-exposure means. The light guide 57 is made of, 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 the surface of the photosensitive drum 1 is irradiated with the light while being uniformly dispersed in the longitudinal direction by the light guide 57 . be done. As a result, the potential on the surface of the photosensitive drum 1 is stabilized, and a good toner image can be formed.

Similarly, the photosensitive drums of the process cartridges PPM, PPC, and PPK are also irradiated with laser light from the scanner unit 11, and magenta (M), cyan (C), and black (K) toner images are formed on the respective photosensitive drums. be done. A toner image of each color formed on each photosensitive drum is 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 image transferred to the intermediate transfer belt 13 is conveyed to the secondary transfer nip T2 by the intermediate transfer belt 13 rotated by the driving roller 14 . Note that the image forming process of each color is performed at the timing of superimposing it on the upstream toner image that has been primarily transferred onto the intermediate transfer belt 13 .

In parallel with this image forming process, the skew feeding of the sheet S sent out by the sheet feeding section 18 is corrected by the registration roller pair 22 . Further, the registration roller pair 22 conveys the sheet S toward the secondary transfer roller 27 in accordance with the toner image conveyed by the intermediate transfer belt 13 . The full-color toner image on the intermediate transfer belt 13 is transferred to the sheet S at the secondary transfer nip T2 by the secondary transfer bias applied to the secondary transfer roller 27 . Further, after the toner image is transferred, 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).

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 , and the toner is melted and then fixed, whereby the image is fixed on the sheet S. After passing through the fixing device 23 , the sheet S is discharged to the discharge tray 25 by the discharge roller pair 24 .

[Cartridge tray]
Next, the configuration of the cartridge tray 40 as a drawer will be described. As shown in FIGS. 4(a) and 4(b), the cartridge tray 40 has tray side plates 41L and 41R which are arranged with a gap in the horizontal direction, and connection members 42, 43 and 44 which connect the tray side plates 41L and 41R. , 45, 46 and guide members 47L, 47R. In addition, in the following description, regarding members provided as a pair on the left and right, the left and right are distinguished by adding “L” or “R” at the end of the reference numerals.

The connecting members 42, 43, 44, 45, 46 are made of resin material and are arranged in order from the front side to the rear side. The connecting members 42, 43, 44 and 45 are provided with the light guides 57 described above. The tray side plates 41L and 41R are made of a metal material, the guide member 47L is supported by the tray side plate 41L, and the guide member 47R is supported by the tray side plate 41R. The guide members 47L, 47R are slidable on a plurality of rollers 56L, 56R provided in the holders 52L, 52R (see FIGS. 11(a) and 12(b)). Further, guide grooves 47aL and 47aR are formed in the guide members 47L and 47R, respectively. Further, the guide grooves 47aL and 47aR restrict the cartridge tray 40 from being pulled out beyond a predetermined position by engaging with a stopper (not shown) provided on the apparatus main body 100A.

The connecting member 42 has receiving portions 42b, 42b and a grip portion 42d. By gripping and pulling out the grip portion 42d by the user, the cartridge tray 40 can be pulled out from the apparatus main body 100A. Further, when the front door 31 is closed and the printer 100 receives a forward impact, the receiving portions 42b, 42b prevent the internal parts of the printer 100 from being damaged by coming into contact with the front door 31. FIG. Similarly, the connecting member 46 has receiving portions 46a, 46a, and the receiving portions 46a, 46a come into contact with the fixing stay 35 (see FIG. 6) when the printer 100 receives a rearward impact. This prevents the internal parts of the printer 100 from being damaged.

The upper portions of the tray side plates 41L and 41R are tapered outward compared to the lower portions, and the distance in the horizontal direction between the tray side plates 41L and 41R is wider at the upper portion and narrower at the lower portion. As a result, the lateral width of the cartridge tray 40 can be reduced without impairing the insertion/removability of the process cartridges PPY, PPM, PPC, and PPK, which contributes to the miniaturization of the printer 100 .

Further, the lower sides of the tray side plates 41L and 41R are L-shaped to ensure strength. The tray side plates 41L, 41R and the connecting members 42, 43, 44, 45, and 46 are fastened with screws, respectively, but not limited to this, heat caulking or the like may be used. Alternatively, only the connecting members 42 and 46 may be fastened to the tray side plates 41L and 41R, and the connecting members 43, 44 and 45 may not be fastened to the tray side plates 41L and 41R.

As shown in FIGS. 4A to 5B, the tray side plate 41R is provided with cartridge engaging portions 41gR, 41hR, 41iR and 41jR. are formed in a substantially V shape. Specifically, the cartridge engaging portions 41gR, 41hR, 41iR, and 41jR are formed so that the front slope is 65° and the rear slope is 45° with respect to the pull-out direction.

The drum flanges 1a (see FIG. 3A) of the process cartridges PPY, PPM, PPC and PPK are engaged with the cartridge engaging portions 41gR, 41hR, 41iR and 41jR. As a result, the process cartridges PPY, PPM, PPC and PPK are positioned with respect to the cartridge tray 40 by being pressed downward by their own weight or by the pressing units 33 and 34 (see FIG. 11(a)). Pressing units 33 and 34 as second pressing units position each process cartridge and the cartridge tray 40 integrated with each process cartridge in the apparatus main body 100A by pressing each process cartridge downward during image formation. The tray side plate 41L is similarly formed with a cartridge engaging portion (not shown), and the process cartridges PPY, PPM, PPC, and PPK are also positioned with respect to the tray side plate 41L.

Bosses 42aL, 43aL, 44aL, and 45aL are formed on the left ends of the connecting members 42, 43, 44, and 45, respectively, and boss portions 42aR, 43aR, 44aR, and 45aR are formed on the right ends, respectively. As shown in FIGS. 3(a) and 3(b), grooves 1d, 1d are formed at the left and right ends of each color process cartridge. The grooves 1d, 1d of the process cartridges PPY, PPM, PPC, and PPK engage with the bosses 42aL, 43aL, 44aL, and 45aL on the left end side, and the bosses 42aR, 43aR, 44aR, and 45aR on the right end side. to engage. As a result, the process cartridges PPY, PPM, PPC, and PPK are prevented from rotating with respect to the cartridge tray 40 .

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

[Cartridge Tray Positioning Configuration]
Next, the positioning structure of the cartridge tray 40 will be described. The apparatus main body 100A and the cartridge tray 40 constitute a positioning device. As shown in FIG. 6, the apparatus main body 100A (see FIG. 1) includes a pair of left and right main body side plates 36L and 36R, a fixing stay 35 connecting the main body side plates 36L and 36R and partitioning the process area and the fixing area, have. The process area is an area in which the process cartridges PPY, PPM, PPC, and PPK are accommodated, and the fixing area is an area in which the fixing device 23 is accommodated. The body side plates 36L, 36R and the fixing stay 35 are made of metal material.

The main body side plates 36L and 36R as the first support portion and the second support portion respectively have shaft support portions 50aL and 50aR on the back side of the apparatus, and the positioning shaft 50 is supported by these shaft support portions 50aL and 50aR. there is Although the positioning shaft 50 is immovably fixed to the shaft support portions 50aL and 50aR, it may be rotatably supported as long as it is immovable in the longitudinal direction and the vertical direction.

The body side plates 36L and 36R have positioning grooves 36aL and 36aR on the front side of the device, respectively. As shown in FIG. 7, shaft supports 41dL and 41dR are formed on the front sides of the tray side plates 41L and 41R of the cartridge tray 40, respectively. A positioning shaft 49 is supported by the shaft support portions 41dL and 41dR. The positioning shaft 49 passes through the tray side plates 41L and 41R, and the left end 49a and the right end (not shown) of the positioning shaft 49 protrude outside the tray side plates 41L and 41R. Although the positioning shaft 49 is immovably fixed to the shaft supports 41dL and 41dR, it may be rotatably supported as long as it is immovable in the front-rear direction and the vertical direction. Further, the positioning shafts 49 and 50 extend in the left-right direction and are constituted by round bar-shaped shafts having a circular cross section, but the shape thereof is not limited.

The connecting member 42 is formed with a shaft contact portion 42c that supports a substantially central portion of the positioning shaft 49 in the axial direction. The shaft contact portion 42c is not limited to the substantially central portion of the positioning shaft 49 in the axial direction, and may support other positions of the positioning shaft 49. It is preferable to regulate at the central portion. Also, the axial contact portion 42c may be formed to be elongated in the axial direction.

As shown in FIG. 8(d), the positioning groove 36aR of the main body side plate 36R is formed along the mounting direction Y1 of the cartridge tray 40. The fitting groove 37aR is formed on the back side and the fitting groove 37aR is formed on the front side. and a guide groove 37bR.

The fitting groove 37aR has a width equal to or slightly smaller than the outer diameter of the positioning shaft 49, and is fitted to the end portion 49a of the positioning shaft 49 when the cartridge tray 40 is positioned at the mounting position. The guide groove 37bR has a width larger than the outer diameter of the positioning shaft 49, and guides the end portion 49a of the positioning shaft 49 to the fitting groove 37aR when the cartridge tray 40 is attached to the apparatus main body 100A. The guide groove and the fitting groove are also formed in the main body side plate 36L in the same manner, and guide or engage the left end of the positioning shaft 49. As shown in FIG.

As shown in FIG. 5B, the tray side plates 41L and 41R are formed with positioning grooves 41bL and 41bR on the inner side, respectively. Position the tray 40 . 8(a) to 8(c) are enlarged views showing the positioning groove 41bL. Since the engaged portion and the positioning grooves 41bL and 41bR as the first engaged portion and the second engaged portion have the same configuration, only the positioning groove 41bR will be described, and the description of the positioning groove 41bL will be omitted. do.

As shown in FIGS. 8A to 8C, the positioning groove 41bR has an inclined surface 41f and a positioning surface 41e formed continuously with the inclined surface 41f. The positioning surface 41e extends in a direction substantially perpendicular to the mounting direction Y1 of the cartridge tray 40, and abuts against the positioning shaft 50 to position the cartridge tray 40 in the mounting direction. The inclined surface 41f is inclined downward in the mounting direction Y1. A sliding surface 46d (see FIG. 5B) is formed on the connecting member 46 of the cartridge tray 40, and the sliding surface 46d is formed so as to continue from the inclined surface 41f to the front side. there is

As shown in FIG. 8(a), when the cartridge tray 40 is mounted, downward force is applied by the weight of the cartridge tray 40 and the pressing units 33 and 34 (see FIG. 11(a)). The inclined surface 41f receives a reaction force F1 from the positioning shaft 50. As shown in FIG. Since the reaction force F1 has a component force F2 in the mounting direction Y1, the cartridge tray 40 is pulled in the mounting direction Y1 by this component force F2. As a result, the positioning surface 41e is pressed against the positioning shaft 50, and the cartridge tray 40 can be accurately positioned with respect to the apparatus main assembly 100A. Thus, the inclined surface 41f is formed so as to generate a force component F2, which is a force acting in the mounting direction Y1, on the cartridge tray 40. As shown in FIG.

As shown in FIG. 9, the positioning shaft 50 is supported by shaft support portions 50aL and 50aR of the body side plates 36L and 36R. When the cartridge tray 40 is attached to the apparatus main body 100A, the positioning grooves 41bL and 41bR are located axially inside the shaft support portions 50aL and 50aR. Therefore, the central portion of the positioning shaft 50 is subjected to downward force by the weight of the cartridge tray 40 and the pressing units 33 and 34 (see FIG. 11(a)), and bends downward (in the direction of the white arrow in the figure). there is a risk of

Therefore, in the present embodiment, a rib 46b is formed as a contact portion at substantially the central portion of the connecting member 46 in the axial direction (horizontal direction). That is, the rib 46b is arranged between the body side plates 36L and 36R in the axial direction and between the positioning grooves 41bL and 41bR. The rib 46b abuts against and supports the substantially central portion between the positioning grooves 41bL and 41bR in the axial direction, thereby restricting the downward deflection of the positioning shaft 50. As shown in FIG. The rib 46b is not limited to the substantially central portion of the positioning shaft 50 in the axial direction, and may support other positions of the positioning shaft 50. However, the downward deflection of the positioning shaft 50 is It is preferable to regulate with Moreover, the rib 46b may be formed to be elongated in the axial direction, or a plurality of ribs 46b may be provided in the axial direction. In the present embodiment, the downward deflection of the positioning shaft 50 is restricted because the positioning shaft 50 receives force in the predetermined direction of gravity. It is not necessary to contact the lower portion of the positioning shaft 50 if the bending of the positioning shaft 50 is to be restricted.

9 and 10, the connecting member 46 is formed with engagement portions 46c, 46c that can be engaged with the fixing stay 35. As shown in FIGS. By engaging the fixing stay 35 with the engaging portions 46 c , 46 c , the downward bending of the cartridge tray 40 including the connecting member 46 can be restricted. By suppressing the downward deflection of the cartridge tray 40, the deformation of the positioning grooves 41bL and 41bR of the cartridge tray 40 is also suppressed, and the cartridge tray 40 can be positioned with high accuracy with respect to the positioning shaft 50. FIG. It should be noted that the locking portions 46c, 46c do not interfere with the mounting operation of the cartridge tray 40, and may be provided with one or three or more. Also, one engaging portion 46c may be formed to be elongated in the axial direction (horizontal direction).

[Cartridge Tray Extraction and Mounting Operation]
Next, the operation of drawing out and mounting the cartridge tray 40 will be described. Each of the process cartridges PPY, PPM, PPC and PPK loses its commercial value as a process cartridge when the developer is consumed to such an extent that it is no longer possible to form an image of satisfactory quality for the user who purchased it.

Therefore, for example, means (not shown) for detecting the remaining amount of developer in each process cartridge is provided, and the control unit 200 detects the remaining amount of developer, and detects the remaining amount of developer by setting a predetermined cartridge life notice or life warning threshold value. can be compared with For a process cartridge whose detected remaining amount value is less than the threshold value, a display section (not shown) displays a life notice or a life warning for the process cartridge, prompting the user to replace the process cartridge. encourage Then, the user opens the front door 31 of the printer 100, pulls the cartridge tray 40 out of the apparatus, and replaces the process cartridges PPY, PPM, PPC, and PPK. Below, the pullout and mounting operations of the cartridge tray 40 will be described in detail.

As shown in FIGS. 11A to 12B, the front door 31 as a door member is supported so as to be openable and closable with respect to the apparatus main body 100A. It can be held in an open state by the connected door links 32L and 32R.

When the front door 31 is opened by the user, a plurality of link members (not shown) are interlocked via the door links 32L and 32R, and the transfer unit 12 rotates around the driving roller 14 by about 1°. As a result, the photosensitive drum 1 of each process cartridge is separated from the intermediate transfer belt 13, as shown in FIG. 13(c).

Next, as shown in FIG. 12(b), the contact 38 provided on the left side (non-driving side) of the apparatus main body 100A retreats from the contact 2 (see FIG. 3(b)) of each developing roller 3, and The pressing of the pressing units 33 and 34 is released. Next, the drum coupling 1c and the developing coupling 3c (FIG. 3(a)) on the drive side of each process cartridge are disengaged, and as shown in FIGS. 11(b) and 13(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 taken out of the apparatus main body 100A.

Here, the tray pressing unit 51 as the first pressing unit is provided in holders 52L and 52R supported by the main body side plates 36L and 36R, respectively, and presses the cartridge tray 40 from the rear side to the front side during image formation. . The tray pressing unit 51 has a tray pressing lever 53, a tray pressing link 54, and an urging spring 55, as shown in FIGS. 13(a) and 13(b).

As shown in FIG. 13A, the tray pressing lever 53 is pressed by a tray pressing link 54 biased by a biasing spring 55 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 rearward.

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 FIG. 13(b). As a result, the rear pressure of the cartridge tray 40 by the tray pressing lever 53 is released, and the cartridge tray 40 can be taken out of the apparatus main assembly 100A.

Next, the movement around the positioning shafts 49 and 50 will be described with reference to FIGS. 8(a) to 8(f). , only the right side of the device will be described, and the description of the left side of the device will be omitted. As shown in FIGS. 8(a) to 8(f), when the cartridge tray 40 starts to be pulled out, the inclined surface 41f slides on the positioning shaft 50, so that the far side of the cartridge tray 40 is slightly lifted. Then, the cartridge tray 40 moves in the pull-out direction Y2 while the sliding surface 46d provided on the connecting member 46 of the cartridge tray 40 slides on the positioning shaft 50. As shown in FIG.

At the same time, the end 49a of the positioning shaft 49 of the cartridge tray 40 comes out of 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 pull-out direction Y2 while the end 49a of the positioning shaft 49 is guided by the guide groove 37bR. 8(a) and 8(d) show a state in which the cartridge tray 40 is positioned at the mounting position. 8B and 8E show a state in which the cartridge tray 40 is pulled out by about 3 mm from the mounting position. 8(c) and 8(f) show a state in which the cartridge tray 40 is pulled out by about 10 mm from the mounting position.

When the cartridge tray 40 is pulled out to some extent, the guide members 47L and 47R of the cartridge tray 40 are guided by the rollers 56L and 56R as shown in FIGS. 11(b) and 12(b). Then, the cartridge tray 40 is pulled out of the apparatus main assembly 100A. During image formation, the cartridge tray 40 and the rollers 56L and 56R are not in contact with each other, ensuring a clearance of about 0.5 mm.

When the cartridge tray 40 is pulled out and the process cartridge is replaced, the cartridge tray 40 is attached to the apparatus main body 100A. The mounting operation when mounting the cartridge tray 40 to the apparatus main body 100A is the reverse of the pulling-out operation. At this time, the sliding surface 46d first begins to slide on the positioning shaft 50, and as shown in FIGS. 49a is transferred from the guide groove 37bR to the fitting groove 37aR.

A boundary portion between the guide groove 37bR and the fitting groove 37aR is inclined upward, and the end portion 49a of the positioning shaft 49 is fitted in the fitting groove 37aR. operation force increases. However, since the positioning shaft 49 enters the fitting groove 37aR after the sliding surface 46d has passed the positioning shaft 50, the user's operation force is not concentrated at the timing when it becomes large, and the operation force can be reduced. When the cartridge tray 40 is inserted to the mounting position by a predetermined distance, the cartridge tray 40 is automatically drawn to the mounting position by a retracting device, which will be described later.

When the cartridge tray 40 is inserted to the mounting position and the front door 31 is closed, the tray pressing unit 51 pushes the cartridge tray 40 backward as shown in FIGS. press to the side. Then, the drum coupling 1c and the developing coupling 3c (see FIG. 3A) on the drive side of each process cartridge are engaged, and the pressing units 33 and 34 press each process cartridge from above. Further, the contact 38 comes into contact with the contact 2 (see FIG. 3B) of each developing roller 3, and the transfer unit 12 rotates upward around the driving roller 14. As shown in FIG. As a result, the photosensitive drum 1 of each process cartridge comes into contact with the intermediate transfer belt 13 .

As described above, when the front door 31 is closed and the printer 100 is ready for image formation, the positioning shaft 50 is engaged with the positioning grooves 41bL and 41bR on the front side of the cartridge tray 40. FIG. At this time, since the positioning grooves 41bL and 41bR are provided with inclined surfaces 41f, the cartridge tray 40 is pulled in the mounting direction Y1 based on the weight of the cartridge tray 40 and the downward force of the pressing units 33 and 34. FIG. 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 mounting direction Y1.

Further, on the rear side of the cartridge tray 40, the positioning shaft 49 is engaged with the positioning grooves 36aL and 36aR. At this time, the end portion 49a of the positioning shaft 49 is fitted into the fitting grooves of the positioning grooves 36aL and 36aR, so that rotation of the cartridge tray 40 about the positioning shaft 50 is prevented. be able to.

The positioning shaft 50 and the positioning grooves 36aL and 36aR provided in the apparatus main body 100A and the positioning grooves 41bL and 41bR and the positioning shaft 50 provided in the cartridge tray 40 constitute a positioning mechanism 60 (see FIGS. 8A and 8D). do. The positioning mechanism 60 positions the cartridge tray 40 in the apparatus main assembly 100A.

Furthermore, since the positioning shaft 50 is supported by the ribs 46b provided on the connecting member 46 of the cartridge tray 40, downward deflection of the positioning shaft 50 is restricted. In addition, deformation of the cartridge tray 40 itself is suppressed by the locking portions 46c, 46c provided on the connecting member 46. As shown in FIG. Further, since the positioning shaft 50 on the rear side of the cartridge tray 40 is also supported by the shaft contact portion 42c, the downward deflection of the positioning shaft 49 is restricted. By configuring in this way, the shaft diameter of the positioning shafts 49 and 50 can be made small, or they can be made of inexpensive resin material, and the cost and size can be reduced.

As a result, the cartridge tray 40 can be accurately positioned in the apparatus main body 100A at the mounting position. In particular, each process cartridge held in the cartridge tray 40 is pressed from above by the pressing units 33 and 34 during image formation, but this does not affect the positioning accuracy of the cartridge tray 40 . Accordingly, 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, and high quality images can be formed.

Further, the cartridge tray 40 is urged forward at the mounting position by the action of the inclined surface 41f on the front side of the cartridge tray 40 and the pressure by the tray pressing unit 51 on the rear side. Therefore, it is possible to reduce the positional deviation of the cartridge tray 40 due to vibration or the like during image formation. Further, by generating the pushing force in front and behind the cartridge tray 40, the pushing force can be dispersed and the urging spring 55 of the tray pushing unit 51 can be made to have a small elastic force. As a result, the size and cost of the tray pressing unit 51 can be reduced.

The positioning shaft 50 and the positioning grooves 41bL and 41bR included in the positioning mechanism 60 may be replaced with each other as long as they are separately arranged in one of the apparatus main body 100A and the cartridge tray 40 and the other. Further, the positioning grooves 36aL and 36aR and the positioning shaft 50 included in the positioning mechanism 60 may be replaced with each other as long as they are separately arranged in one of the apparatus main body 100A and the cartridge tray 40 and the other.

Further, the positioning shaft 49 does not have to be a through shaft extending over the entire length of the cartridge tray 40 in the left-right direction.

Further, although each process cartridge is formed integrally with the drum unit OP and the developing unit DP, the drum unit OP and the developing unit DP may be formed separately. For example, the cartridge tray 40 may hold only the drum unit OP or only the developing unit DP.

[Retraction device]
The retracting device 90 of this embodiment will be described below. As shown in FIGS. 14 and 15, the retracting device 90 has a function of retracting the cartridge tray 40, which is an example of a unit that can be pulled out from the apparatus main body, to a predetermined position (mounting position in FIG. 15 in this embodiment) of the apparatus main body. have.

FIG. 14 shows a state seen from above before the retracting device 90 retracts the cartridge tray 40 . The retracting device 90 includes a holder 91, an arm 92, an arm spring 93, and a locking member 94, which are arranged on the device main body side, and a first operating portion 46s1 and a second operating portion 46s2 provided on the cartridge tray side. I have. The arm 92 is the arm member of this embodiment, the lock member 94 is the regulating member of this embodiment, and the arm spring 93 is the biasing means of this embodiment. Also, the first operating portion 46s1 is the first contact portion of the present embodiment, and the second operating portion 46s2 is the second contact portion of the present embodiment.

The holder 91 is fixed to the fixing stay 35 of the main body of the apparatus, and rotatably holds the arm 92 by a rotation fulcrum portion 91o. The arm 92 is always biased clockwise in the figure by an arm spring 93 . This urging force causes the arm 92 to retract the first operating portion 46s1 to move the cartridge tray 40 toward the rear of the apparatus, resulting in the retracted state shown in FIG. In the retracted state, the cartridge tray 40 is positioned by engaging the above-described tray positioning portion 41b with the positioning shaft 50 and engaging the tray positioning shaft 49 with the main body positioning portions 36a and 37a. In the standby state shown in FIG. 14 (where the cartridge tray 40 is pulled out to the position where the process cartridge PP is attached and detached), the rotation of the arm 92 is restricted by a locking mechanism, which will be described later.

The biasing force applied to the arm 92 by the arm spring 93 is adjusted according to the overall weight of the cartridge tray 40 including the process cartridges PP. In the configuration example to which this embodiment is applied, good operability was obtained when the biasing force of the arm 92 was set to 2 kg. This value is about 1 kg to 1.5 kg when converted into a force for pulling the cartridge tray 40 in the mounting direction. This is set smaller than the force in the same direction generated by the contact between the tray pressing unit 51 and the positioning shaft 49 described above and the inclined surface 41f. On the other hand, the magnitude of the urging force of the arm spring 93 is set so as to overcome the sliding resistance between the sliding surface 46d (FIG. 8) and the positioning shaft 50, thereby retracting the cartridge tray 40 to the mounting position. be.

FIGS. 16A and 16B show the configuration of the device body side of the drawing-in device 90 viewed from above (a), horizontally (b), and below (c). In the drawing, the left-right direction of the image forming apparatus is the X-axis direction, the front-rear direction (the mounting direction of the cartridge tray 40) is the Y-axis direction, and the vertical direction perpendicular to the X-axis direction and the Y-axis direction is the Z-axis direction.

The arm 92 is rotatable between a standby state position shown in FIGS. 14 and 16 and a retracted position shown in FIG. In other words, the direction of the rotation axis of the arm 92 in this embodiment substantially coincides with the vertical direction. Hereinafter, the position of the arm 92 in the standby state will be referred to as "standby position", and the position of the arm 92 in the retracted state will be referred to as "retracted position". The rotation direction (first direction) of the arm 92 from the standby position to the retracted position is defined as the "retraction direction", and the rotation direction (second direction) of the arm 92 from the retracted position to the standby position is defined as the "return direction". and

At the standby position, the arm 92 protrudes toward the front side of the image forming apparatus through an opening 35 o ( FIG. 14 ) provided in the front wall surface 35 a of the fixing stay 35 . When moved to the retracted position, the arm 92 retreats to the rear side of the image forming apparatus with respect to the opening 35o together with the first operating portion 46s1 and the second operating portion 46s2 (FIG. 15). Further, the arm spring 93 of this embodiment is configured to urge the arm 92 in the retraction direction R1 over the entire range from the standby position to the retracted position.

As shown in FIGS. 16(a) to 16(c), the arm 92 is provided with a first engagement surface 92s and a second engagement surface 92d that contact the first operating portion 46s1. The first engaging surface 92s is a portion that contacts the first operating portion 46s1 in the initial stage of the retraction operation to unlock the lock mechanism. The second engaging surface 92d is a portion that contacts the first operating portion 46s1 after the lock mechanism is unlocked in order to receive the force of the arm 92 rotating by the biasing force of the arm spring 93 to pull in the cartridge tray 40 .

17 is an exploded view of arms 92 and 94. FIG. The arm 92 connects an arm upper portion 92a, which is the first portion of the present embodiment, and an arm lower portion 92b, which is the second portion of the present embodiment, by means of fasteners such as screws and elastic claw portions 92m and hole portions 92n. It is integrated by Lock member 94 is held between upper arm portion 92a and lower arm portion 92b. The lock member 94 includes a pressing portion 94s that is pressed by the second operating portion 46s2 when the cartridge tray 40 is inserted, and a contacted portion 911 provided on the holder 91 (that is, fixed to the apparatus main body). (FIG. 18).

The lock member 94 and the lock spring 95 constitute a lock mechanism that locks the arm 92 at the standby position when the cartridge tray 40 is pulled out. Hereinafter, the position where the abutment portion 941 faces the abutted portion 911 and restricts the rotation of the arm 92 is referred to as the "lock position" of the lock member 94, and the abutment portion 941 is separated from the abutted portion 911. A position at which the arm 92 is allowed to rotate is defined as an “unlocked position” of the lock member 94 .

The lock member 94 is rotatably supported by the arm 92 about a pivot point 92o, and is constantly biased counterclockwise in the drawing by a lock spring 95. As shown in FIG. The biasing force of the lock spring 95 is set to be weaker than that of the arm spring 93 as long as it can restrict the free rotation of the lock member 94 with respect to the arm 92 . In the configuration example to which the present embodiment is applied, it is preferable to set the biasing force of the arm spring 93 to 50 g.

As shown in FIG. 16(b), the lock member 94, which is a plate-like member, is in a posture perpendicular to the Z-axis direction, and the upper arm portion 92a and the lower arm portion 92b, which are two plate-like members, are engaged with each other. sandwiched between. That is, the thickness of the lock member 94 is smaller than the interval z1 between the arm upper portion 92a and the arm lower portion 92b in the Z-axis direction. The space z1 is set to a size that does not allow a human fingertip to enter, for example, 5 mm or less.

Slopes 92a1 and 92b1 of an upper arm portion 92a and a lower arm portion 92b are provided at the end of the arm 92 at the standby position on the upstream side in the mounting direction Y1 as a guide shape for guiding the second operating portion 46s2 on the cartridge tray side. It is The slopes 92a1 and 92b1 face each other in the Z-axis direction, and are inclined with respect to the XY plane so that the interval in the Z-axis direction becomes narrower downstream in the mounting direction Y1. In addition, the slopes 92a1 and 92b1 are formed in a range overlapping the position p1 where the second operating portion 46s2 first contacts the lock member 94 in the X-axis direction.

As shown in FIGS. 14 and 18(a), the first operating portion 46s1 and the second operating portion 46s2 are provided on the rearmost connecting member 46 of the cartridge tray 40. As shown in FIGS. The first operating portion 46s1 and the second operating portion 46s2 of the present embodiment are resin molded products 46s that are integrally molded from a resin material, and protrude downstream from the connecting member 46 in the mounting direction of the cartridge tray 40. As shown in FIG. The first operating portion 46s1 has a columnar shape extending in the Z-axis direction, and the second operating portion 46s2 has a plate-like shape perpendicular to the Z-axis direction. The thickness of the second operating portion 46s2 is set to a value smaller than the interval z1 between the arm upper portion 92a and the arm lower portion 92b.

[Operation of retraction device]
The operation of the retracting device 90 will be described below with reference to FIGS. 18 to 21. FIG. 18 shows a standby state in which the cartridge tray 40 is pulled out from the main body of the apparatus, FIG. 19 shows the first step of unlocking operation, FIG. 20 shows the second step of unlocking operation, and FIG. It corresponds to the pull-in state. Further, (a) of each figure is a view of the drawing device 90 viewed from above, and (b) is a perspective view in which a part of the arm upper portion 92a is made invisible from (a).

In the standby state shown in FIGS. 18A and 18B, the first operating portion 46s1 and the second operating portion 46s2 are separated from the arm 92, and the arm 92 is at the standby position. (Although the cartridge tray 40 is shown in FIG. 18 for explanation, when the process cartridge is attached or detached, the cartridge tray 40 is positioned below the range of FIG. 18 from the arm 92.) In the standby state, As shown in FIG. 18(b), the lock member 94 is engaged with the holder 91, and the arm 92 is in a locked state in which rotation in the retraction direction R1 is restricted. That is, the arm 92 is biased in the clockwise direction in the figure by the arm spring 93, but the lock member 94 pivotally supported by the arm 92 contacts the contacted portion 911 of the holder 91 at the contact portion 941. there is Therefore, the rotation fulcrum 92o of the lock member 94 cannot move in the retraction direction R1 with respect to the rotation fulcrum portion 91o of the arm 92, and the arm 92 does not rotate in the retraction direction.

Further, in the standby state, the locking member 94 is pressed counterclockwise (r1) in the drawing by the reaction force from the contacted portion 911, but the wall surface 912 (FIG. 20(b)) adjacent to the contacted portion 911 is pressed. ) abuts. Therefore, the lock member 94 is restricted from rotating counterclockwise in the standby state, and the lock member 94 is maintained at the lock position.

FIGS. 19A and 19B show the state of the first stage of the unlocking operation in which the arm 92 is unlocked while the cartridge tray 40 is being inserted into the apparatus main body. When the cartridge tray 40 approaches the arm 92 in the tray mounting direction Y1, the first operating portion 46s1 comes into contact with the first engagement surface 92s of the arm 92 first. When the arm 92 is at the standby position, the first engaging surface 92s extends downstream in the mounting direction Y1 so as to enter from the outside to the inside of the range of the first operating portion 46s1 in the X-axis direction (that is, upward in the drawing). towards the left). Therefore, as the cartridge tray 40 is inserted, the first operating portion 46s1 presses the first engaging surface 92s leftward in the figure, and rotates the arm 92 in the return direction R2 against the biasing force of the arm spring 93. .

Then, as shown in FIG. 19B, the abutment portion 941 of the lock member 94 is separated from the abutted portion 911 of the holder 91 to form a gap g, and the lock member 94 can move with respect to the arm 92 ( (rotatable clockwise in the drawing). However, even in this state, the lock member 94 is urged clockwise (r1) in the figure by the urging force of the lock spring 95 and comes into contact with the wall surface 912 of the holder 91 . Therefore, the lock member 94 remains at the locked position, and the locked state of the arm 92 is not released. 19, even if the arm 92 is artificially rotated in the retraction direction R1 without moving the cartridge tray 40, the abutting portion 941 of the lock member 94 will not move to the abutted portion 911 of the holder 91. , and the rotation of the arm 92 is restricted.

20(a) and 20(b) show a state in which the cartridge tray 40 is further inserted into the apparatus main body, and the unlocking operation proceeds to the second stage. At this stage, the second operating portion 46s2 presses the pressing portion 94s of the lock member 94 while the first operating portion 46s1 of the cartridge tray 40 rotates the arm 92 from the standby position in the return direction R2. As a result, the lock member 94 rotates in the clockwise direction (r2) in the drawing against the biasing force of the lock spring 95, and the contact portion 941 of the lock member 94 is locked so that it does not face the contact portion 911 of the holder 91. Move away to the release position.

While the lock member 94 rotates from the locked position to the unlocked position, the arm 92 is kept rotated in the return direction R2 from the standby position. In other words, the shape of the first engaging surface 92 s is designed to ensure the amount of rotation of the arm 92 that allows the locking member 94 to rotate to the unlocked position without interfering with the abutted portion 911 . For example, the shortest distance from the rotation fulcrum 92o of the lock member 94 to the contacted portion 911 is between the second operating portion 46s2 coming into contact with the locking member 94 and the contacting portion 941 separating from the contacted portion 911. The distance should be smaller than the turning radius of the contact portion 941 with respect to the turning fulcrum 92o.

The second operating portion 46s2 moves the lock member 94 to the unlocked position, so that the lock member 94 does not prevent the arm 92 from rotating in the retraction direction R1 (unlocked state). That is, if the cartridge tray 40 is removed from the state shown in FIG. 20 while the positions of the arm 92 and the lock member 94 are maintained, the biasing force of the arm spring 93 causes the arm 92 to rotate in the retraction direction R1.

The second engaging surface 92s of the arm 92 engages the first operating portion 46s1 while the arm 92 is unlocked by the second operating portion 46s2. When the second engaging surface 92s is engaged with the first operating portion 46s1, the biasing force of the arm spring 93 causes the arm 92 to pull the cartridge tray 40 in the mounting direction Y1. In other words, the normal vector of the second engaging surface 92s includes a positive component in the Y-axis direction in the process of inserting the cartridge tray 40 in the surface area of the arm 92 that contacts the first operating portion 46s1. It begins to abut against the first actuation portion 46s1 in the orientation.

As shown in FIGS. 21A and 21B, the arm 92 is rotated by a predetermined angle (about 45° in this embodiment) from the standby position while pulling the cartridge tray 40 in the mounting direction Y1 by the biasing force of the arm spring 93. Then the retracted position is reached. As a result, the cartridge tray 40 is mounted at the mounting position of the apparatus main body.

When the cartridge tray 40 is pulled out from the main body of the apparatus, the retracting device 90 reverses the above described retracting operation to change from the retracted state shown in FIG. 21 to the standby state shown in FIG. That is, when the user or the like pulls the cartridge tray 40 in the pull-out direction opposite to the mounting direction Y1, the first operating portion 46s1 presses the second engaging surface 92d of the arm 92 in the pull-out direction. As a result, the arm 92 rotates in the return direction R2, and the state shown in FIG. 21 changes to the state shown in FIG. The lock member 94 rotates counterclockwise in the drawing by the biasing force of the lock spring 95 while the pressing portion 94s is kept in contact with the second operating portion 46s2, and is locked as shown in FIG. return to position.

Further, when the cartridge tray 40 is pulled out, the second operating portion 46s2 is separated from the pressing portion 94s of the lock member 94. As shown in FIG. Also, the first operating portion 46s1 rotates the arm 92 in the return direction R2 to a position beyond the standby position. Thereafter, the arm 92 rotates in the retraction direction R1 to the standby position while sliding on the first operating portion 46s1 on the first engaging surface 92s, and the contact portion 941 of the lock member 94 contacts the contact portion 911 of the holder 91. By abutting, the retracting device 90 enters the standby state shown in FIG.

[Summary of retraction device]
The retracting device 90 of the present embodiment has a structure in which the rotation of the arm 92 is locked in the standby state. ) Requires two actions, that is, the rotation of the locking member 94 . That is, if the above (1) and (2) do not act on the retracting device 90 in this order, basically the arm 92 will not be unlocked. As a result, high stability of the retracting device 90 can be achieved in the standby state before unlocking as shown in FIG. Here, the definition of "high stability" means that it is difficult to cause a situation in which the arm 92 is accidentally unlocked and rotates arbitrarily when the user touches the retracting device 90 in the standby state with a finger. Satoru.

Furthermore, in this embodiment, the locking member 94 is held in a gap between the two arms 92, and access to this gap is required in order to move the locking member 94. . If the lock is to be unlocked by moving the lock member 94 to the unlocked position while the arm 92 is in the standby position, the lock member 94 is moved in the direction of the arrow in FIG. You have to press hard. However, in the standby state, the locking member 94 is pressed against the contacted portion 911 of the holder 91 by the biasing force of the arm spring 93, and a large force is required to rotate the locking member 94 clockwise in the figure. Become. Therefore, it is necessary to insert an object such as a ruler which is thinner than the space z1 (FIG. 16(b)) between the upper arm and the lower arm and is rigid into the gap between the arms 92 and strongly press it. , it is impractical for such behavior to occur accidentally. On the other hand, after rotating the arm 92 in the return direction R2, a two-step operation of rotating the lock member 94 by inserting an object such as a ruler into the clearance of the arm 92 may be performed accidentally. Very Hard to think.

Therefore, the structure of this embodiment, in which the lock member 94 is surrounded and protected by the arm 92, can further improve the stability of the retracting device 90. FIG. In this embodiment, the plate-shaped second operating portion 46s2 is used as the second contact portion, and the thickness of the second operating portion 46s2 is made smaller than the interval z1 between the arms 92, so that the interval z1 between the arms 92 can be adjusted. Objects other than the second operating portion 46s2 are made difficult to enter. Instead of this, even if a non-plate-shaped second contact portion is used, if the second contact portion is arranged between the arm members divided into a plurality of parts, the same effect as in the present embodiment can be obtained. be able to.

In addition, in the retracting device 90 of the present embodiment, at least the arm spring 93 and the pivot point 91o of the arm 92 are arranged behind the front wall surface 35a of the fixing stay 35 (FIG. 14). In this way, with a configuration in which there are few members protruding toward the space in which the cartridge tray 40 is accommodated in the standby state, accidental contact with the retracting device 90 can be reduced, and stability can be further improved. . As shown in FIG. 16(c), the arm 92 is provided with an enclosing portion 92k that covers at least a portion of the lock spring 95 when viewed from the Y-axis direction in the standby state. Preferably, the holder 91 is provided with an overlapping enclosure 91k. These configurations also contribute to improving the stability of the retracting device 90 by preventing careless contact with the lock spring 95 and the lock member 94 . Moreover, not only the fixing stay 35 but also another sheet metal frame or holder 91 may be used to provide an enclosure that covers the movable portion other than the arm 92 .

Further, in this embodiment, the arm spring 93 is configured to bias the arm 92 in the retraction direction R1 over the entire range from the standby position to the retracted position. Therefore, compared to a structure in which the urging direction of the arm by the spring member changes in the middle of the range from the standby position to the retracted position, which is used in a so-called toggle type retracting device, the distance by which the arm 92 can retract the cartridge tray 40 is increased. can be set longer. In the case of the toggle-type retracting device, the retracting action is generated after the arm has passed the neutral position, but the retracting action is weak near the neutral position, and a force in the direction of pushing back the cartridge tray is rather applied before the arm exceeds the neutral position. On the other hand, in the case of the present embodiment, the biasing force of the arm spring 93 is efficiently transmitted as a force to move the cartridge tray 40 in the mounting direction Y1 at the stage of FIG. 20 when the retraction action begins to occur. As a result, compared to a toggle-type retracting device, it is possible to increase the distance at which a sufficient retracting force can be exerted while avoiding an increase in the size of the retracting device.

In addition, this embodiment also has a feature of good storability. When the retracting device 90 retracts the cartridge tray 40 to the mounting position (FIG. 21), the range in the mounting direction Y1 occupied by the retracting device 90 is about half that in the standby state (FIG. 18). At least part of the space occupied by the arm 92 in the standby state contains the cartridge tray 40 in the retracted state. These features make it possible to secure a storage space for the cartridge tray 40 without increasing the size of the housing of the image forming apparatus, thereby contributing to the miniaturization of the apparatus.

The retracting device 90 of the present embodiment has a configuration in which the force that the cartridge tray 40 receives from the arm 92 in the process of the unlocking operation and the retracting operation includes a component toward one side of the X-axis direction (leftward in FIG. 20). It has become. Although the retraction device 90 could be arranged with the illustrated configuration inverted about the X-axis, in this embodiment the force component in the X-axis is directed from the right side plate 37 to the left side plate 36. It is arranged in such a way that it is oriented (see FIG. 14).

Here, in this embodiment, the positioning of the photosensitive drum in the longitudinal direction when the image forming operation is performed after the cartridge tray 40 is attached to the apparatus main body is performed by pressing the photosensitive drum leftward. Specifically, a drive coupling provided in the apparatus main body presses leftward a drum coupling 1c (FIG. 3A) provided coaxially with the photosensitive drum.

With such a configuration, the retracting device 90 of the present embodiment has a force component acting on the cartridge tray 40 in the direction perpendicular to the mounting direction in the process of retracting the cartridge tray 40 so that the photosensitive drum is elongated after the tray is mounted. It is arranged so as to match the direction pressed in the direction. If they were oriented in opposite directions, there would be a guide shape that regulates the position of the tray in the horizontal direction when the cartridge tray 40 is inserted, and a guide that receives the force received by the tray through the photosensitive drum after the tray is mounted and regulates the tray position. It becomes necessary to provide the shape and shape separately. The guide shape refers to, for example, a wall surface facing the guide member 47L of the cartridge tray 40 from the left-right direction. On the other hand, in the present embodiment, since the directions of these forces are the same, it is possible to realize the position regulation function at the time of insertion of the cartridge tray 40 and the position regulation function after installation with a common guide shape. It is possible to simplify the configuration.

Further, as shown in FIG. 14, the cartridge tray 40 is provided with a contact t1 for connecting the photosensitive drum to the ground potential, and the apparatus body is provided with a wire spring t2 connected to the ground potential. The contact t1 is electrically connected to the contact 1b (FIG. 3B) of each process cartridge PP mounted on the cartridge tray 40 via a wire 48 (FIG. 5) mounted on the cartridge tray 40. . When the cartridge tray 40 is mounted at the mounting position of the apparatus main body, the wire spring t2 is pressed against the contact t1, and the photosensitive drum is grounded.

The contact t1 and the wire spring t2 are provided on the left end of the cartridge tray 40, and are not provided on the right side. In such a configuration, the position where the arm 92 presses the first operating portion 46s1 in the cartridge mounting direction when the cartridge tray 40 is mounted is offset to the left with respect to the center position of the cartridge tray 40 in the X-axis direction. there is Therefore, the force with which the cartridge tray 40 is pressed by the wire spring t2 via the contact t1 and the force with which the cartridge tray 40 receives from the retracting device 90 are offset, and the inclination of the cartridge tray 40 is suppressed.

Further, as described above, the process cartridges PPY, PPM, PPC, and PPK are positioned with respect to the cartridge tray 40 rather than the main body of the image forming apparatus. In such a case, if the final positioning of the cartridge tray 40 with respect to the main body is performed by the user's insertion/removal operation, the positioning accuracy may be lowered. If the positioning accuracy of the cartridge tray 40 with respect to the main body is not good, the laser beam irradiation position on the surface of the photosensitive drum 1 deviates from the ideal position, resulting in deviation of the image position on the sheet. In contrast, in the above-described embodiment, the biasing force of the arm spring 93 or the like is used to position the cartridge tray 40 with respect to the main body, so that such problems can be further prevented.

[Modification]
In this embodiment, the first operating portion 46s1 frictionally contacts the first engagement surface 92s of the arm 92 during the process of inserting the cartridge tray 40 into the retracting device 90 (FIG. 20). Therefore, depending on conditions such as the material of the first operating portion 46s1 and the first engaging surface 92s, humidity, etc., the load of the operation of inserting the cartridge tray 40 may increase due to the frictional force. As a countermeasure, instead of the first operating portion 46s1 of the present embodiment, a rotating member that has a cylindrical shape like the first operating portion 46s1 and is rotatably supported by the cartridge tray 40 may be used. . In the present embodiment, the first operating portion 46s1 serves both as a portion that acts on the arm 92 in the initial stage of the unlocking operation and as a portion that receives a pulling force from the arm 92 after unlocking, but these portions are separate. You may arrange|position as a member.

Further, regarding the shape of the first engaging surface 92s of the arm 92, it is preferable to reduce the fluctuation of the load of the operation of inserting the cartridge tray 40 to the position where the retraction of the cartridge tray 40 is started. For example, when the first engaging surface 92s is viewed from the Z-axis direction, it is preferable to form an arcuate shape centered at a position some distance away from the rotation fulcrum portion 91o of the arm 92 . Also, in the present embodiment, all the parts other than the springs (93, 95) are made of resin parts, but it is also conceivable to make parts such as the arm 92 that receive a strong force out of metal parts. It is also conceivable to use a torsion coil spring or a compression spring instead of the tension spring.

Further, even if the arm 92 and the locking member 94 are arranged on the cartridge tray 40 and the first operating portion 46s1 and the second operating portion 46s2 are arranged on the main body of the apparatus, the retraction operation similar to that of the present embodiment is realized. That is, the arm member and the restricting member can be arranged on either one of the device main body and the unit, and the first contact portion and the second contact portion can be arranged on the other of the device main body and the unit. However, disposing the arm 92 and the lock member 94, which are movable members, in the main body of the apparatus as in this embodiment is advantageous in terms of reducing the weight and size of the cartridge tray 40 and reducing damage to the members. .

<<Second Embodiment>>
A retracting device according to the second embodiment will be described. Since only one arm 92 is arranged in the first embodiment, when the cartridge tray 40 is inserted into the main body of the apparatus, the cartridge tray 40 is pressed in either the left or right direction by the arm 92, and the distance between the cartridge tray 40 and the main body of the apparatus is increased. was one of the factors that generate frictional force in the

In this embodiment, as shown in FIG. 23, two arms 92L and 92R are arranged symmetrically. Further, the same locking mechanisms as in the first embodiment including locking members 94L and 94R are arranged symmetrically in correspondence with the arms 92L and 92R. Therefore, the rotation direction R3 (third direction) of the right arm 92R when the cartridge tray 40 is retracted is the rotation direction opposite to the retraction direction R1 of the left arm 92L. Also, the arms 92L and 92R are connected to both ends of an arm spring 93, which is a common biasing means, to receive biasing force. When the left arm 92L and the locking member 94L are the first arm member and the first restricting member, the right arm 92R and the locking member 94R are the second arm member and the second restricting member.

In this embodiment, the detailed configuration of the arms 92L, 92R and the lock members 94L, 94R and the operation when inserting the cartridge tray are the same as the arms 92L and the lock members 94 of the first embodiment. Therefore, with the configuration of this embodiment, it is possible to provide a retraction device that can prevent the lock from being unlocked by mistake.

In addition, in the configuration of the present embodiment, of the forces exerted by the two arms 92L and 92R on the two first operating portions 46s1 and 46s1, the components in the X-axis direction perpendicular to the mounting direction of the cartridge tray 40 are cancel each other out. As a result, the friction between the cartridge tray 40 and the apparatus main body can be reduced, and the operational load can be reduced. In addition, it is possible to prevent the cartridge tray 40 from tilting when viewed from above due to the force received from the retracting device 90 during the insertion operation. Also, if the same spring member as in the first embodiment is used as the arm spring 93, the tension of the arm spring 93 acts on the cartridge tray 40 via the arms 92L and 92R connected to both ends of the spring. The force in the direction is approximately doubled. As a result, even if a spring member that is weaker than that of the first embodiment is used, the necessary pulling force can be secured, so the cost of the arm spring 93 can be reduced.

<<Third Embodiment>>
A retracting device according to the second embodiment will be described. In the first embodiment, the arm 92 holds the lock member 94, but as shown in FIG. 24, the lock member 94A is rotatably held by the holder 91 in the present embodiment. In other words, the regulating member of this embodiment is rotatably supported by the apparatus main body separately from the arm member.

In the standby state, the engagement portion 92e of the arm 92 contacts the lock member 94A, thereby restricting the rotation of the arm 92 in the retraction direction R1. When the cartridge tray 40 is inserted, as shown in FIG. 24, the first operating portion 46s1 provided on the tray presses the first engagement surface 92s of the arm 92 to push the arm 92 against the arm spring 93. It is rotated in the return direction R2 from the standby position. As a result, the engaging portion 92e of the arm 92 is disengaged from the lock member 94A, so that the lock member 94A can rotate clockwise in the figure. However, since the posture of the lock member 94A is maintained by the biasing force of the lock spring 95 in the state shown in FIG. 24, the lock of the arm 92 is not released.

When the cartridge tray 40 is further inserted, as shown in FIG. 25, the second operating portion 46s2 comes into contact with the lock member 94A and rotates the lock member 94A clockwise against the force of the lock spring 95. As shown in FIG. Thereby, the lock of the arm 92 by the lock member 94A is released. With the second engagement surface 92d of the arm 92 in contact with the first operating portion 46s1, the arm 92 rotates in the retraction direction R1 according to the biasing force of the arm spring 93, thereby finally closing the cartridge tray 40. is retracted to the position of FIG.

Also in this embodiment, to unlock the arm 92, (1) the arm 92 is rotated in the return direction R2, and (2) the lock member 94A is rotated. Therefore, with the configuration of this embodiment, it is possible to provide a retraction device that can prevent the lock from being unlocked by mistake.

[Other embodiments]
In the first to third embodiments described above, the drawing device 90 for drawing the cartridge tray 40 into the apparatus main body has been described, but this drawing device 90 can be applied to any device having a unit that can be drawn out from the apparatus main body. be. For example, the present invention can be applied to a configuration in which a cassette 19 (FIG. 2), which is an example of a sheet storage unit for storing sheets used as recording media, is pulled into the apparatus main body. Also, the positioning mechanism for the cartridge tray 40 may be applied to other drawers such as the cassette 19 .

Further, for example, an apparatus main body of an image forming apparatus, a sheet processing device (apparatus for performing processing such as binding processing on sheets) and an optional feeder (device for supplying sheets to the apparatus main body) detachable from the apparatus main body are connected to the apparatus main body. It can be applied to a configuration that pulls into Further, the present invention is not limited to image forming apparatuses, and can be applied to a configuration in which, for example, a drawer of an office desk or a drawer of storage furniture is pulled into the apparatus main body (housing).

Further, in all of the above-described embodiments, the electrophotographic printer 100 is used in the description, but the present invention is not limited to this. For example, the present invention can also be applied to an inkjet image forming apparatus that forms an image on a sheet by ejecting ink liquid from nozzles.

1: photoreceptor (photosensitive drum) / 10: image forming section (image forming unit) / 36aR: second engaging section (positioning groove) / 36L: first supporting section (main body side plate) / 36R: second supporting section ( main body side plate)/40: cartridge tray (drawer portion)/41bL, 41bR: engaged portion, first engaged portion, second engaged portion (positioning groove)/46b: contact portion (rib)/50: Positioning shaft/100: Image forming apparatus (printer)/100A: Apparatus body/DP: Unit (developing unit)/OP: Unit (drum unit)

Claims (9)

A positioning shaft, a first side plate having a first shaft support for supporting the positioning shaft, and a second shaft support for supporting the positioning shaft, and spaced from the first side plate in the axial direction of the positioning shaft a device main body having a second side plate spaced apart from the
a drawer part that can be displaced with respect to the positioning shaft and can be drawn out and attached to the device main body,
The drawer portion is engaged with the positioning shaft in a predetermined direction, and is engaged with an engaged portion that positions the drawer portion with respect to the device main body at a mounting position. and a contact portion that regulates deformation in the predetermined direction of
The engaged portion is arranged between the first side plate and the second side plate in the axial direction when the drawer portion is positioned at the mounting position, and is a first engaged portion that engages with the positioning shaft. having a mating portion and a second engaged portion;
The contact portion is arranged between the first engaged portion and the second engaged portion in the axial direction,
A positioning device characterized by: The contact portion is arranged in a central portion between the first engaged portion and the second engaged portion in the axial direction,
The positioning device according to claim 1, characterized in that: the device body includes a stay connected to the first side plate and the second side plate,
The drawn-out portion has a locking portion that can be locked to the stay,
3. The positioning device according to claim 1 or 2, characterized in that: The locking portion includes a first locking portion and a second locking portion that can be locked to the stay,
4. The positioning device according to claim 3, characterized in that: The drawer portion has a connecting member having the contact portion and the locking portion,
5. The positioning device according to claim 3 or 4, characterized in that: the predetermined direction is the direction of gravity;
The contact portion contacts the lower portion of the positioning shaft when the drawer portion is positioned at the mounting position.
The positioning device according to any one of claims 1 to 5 , characterized in that: The drawer holds a cartridge having a photosensitive member capable of carrying a toner image.
The positioning device according to any one of claims 1 to 6 , characterized in that: the drawer holds a cartridge containing developer;
The positioning device according to any one of claims 1 to 7 , characterized in that: A positioning device according to any one of claims 1 to 8 ;
an image forming unit that forms an image on the sheet;
An image forming apparatus characterized by:

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