Unit support device and image forming apparatus

Abstract

To provide a unit support device that can increase workability in attaching and detaching a unit to and from the unit support device, and an image forming apparatus.SOLUTION: A drawing unit 70 as a unit support device comprises cylindrical shafts 413a, 413b as support members supporting a shaft member 412 as a support target part of a secondary transfer unit 40 as a unit, and is provided drawable from an apparatus body. The drawing unit 70 further comprises a fixing mechanism 130 that fixes the shaft member 412 in an unattachable and undetachable state when the drawing unit is attached to the apparatus body, and changes the shaft member in the unattachable and undetachable state to an attachable and detachable state in conjunction with an operation to draw the drawing unit 70 from the apparatus body.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a unit supporting device and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a unit supporting device that has a supporting portion that supports a supported portion of a unit and is provided so as to be removable from an apparatus main body.

[0003] Patent Document 1 describes a unit support device in which a belt unit consisting of a secondary transfer roller, a separation roller, and a secondary transfer belt stretched around these rollers is supported on a frame. The shaft of the secondary transfer roller and the shaft of the separation roller are fixed to the frame so as not to be detached by a rotary shaft support arm attached to the frame. It describes that the belt unit can be removed from the frame by removing the rotary shaft support arm to make the shaft of the secondary transfer roller and the shaft of the separation roller detachable from the frame. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in order to attach or detach a unit such as a belt unit to or from a unit support device such as a frame, it is necessary to remove and attach the rotating shaft support arm, which poses a problem of poor workability in attaching and detaching the unit. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a unit support device which has a support member that supports a supported portion of a unit and is arranged to be retractable from the device main body, and which is characterized in that when the unit support device is attached to the device main body, it fixes the supported portion of the unit so that it cannot be removed, and is equipped with a fixing mechanism which switches from the non-detachable state to a detachable state in conjunction with the action of pulling the unit support device out of the device main body. Effect of the Invention

[0006] According to the present invention, the ease of attaching and detaching the unit to and from the unit support device can be improved. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a copying machine according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram of the secondary transfer device as viewed from the left-right direction (X direction) of the device. [Diagram 3] FIG. 2 is a schematic configuration diagram of the front side of the secondary transfer device. [Figure 4] FIG. 2 is a schematic diagram of the rear side of the secondary transfer device. [Diagram 5] FIG. 2 is a schematic diagram showing a secondary transfer device mounted in a main body of a copying machine. [Figure 6] FIG. 13 is a schematic configuration diagram of a first modified example. [Figure 7] FIG. 11 is a schematic configuration diagram of a main part of a second modified example. [Figure 8] FIG. 11 is a schematic configuration diagram of a third modified example. [Figure 9] FIG. 13 is a schematic diagram of a main part of a third modified example in which the shaft member is pressed from the left-right direction (X direction) of the device to fix the rear side of the shaft member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The best mode for carrying out the present invention will be described below with reference to the drawings. Note that a person skilled in the art can easily modify and alter the present invention within the scope of the claims to create other embodiments, and these modifications and alterations are included in the scope of the claims. The following description is an example of the best mode for carrying out the present invention, and does not limit the scope of the claims.

[0009] Hereinafter, an embodiment of a tandem type color laser copier (hereinafter simply referred to as a "copier") in which a plurality of photoconductors 1 are arranged in parallel will be described as an image forming apparatus to which the present invention is applied.

[0010] First, the basic configuration of the copying machine according to the embodiment will be described. FIG. 1 is a schematic diagram of a copying machine according to an embodiment. This copying machine comprises a printer section 100, a paper feeder 200 on which the printer section 100 is placed, a scanner 300 fixed on the printer section 100, etc. In addition, it also comprises an automatic document feeder 600 fixed on the scanner 300, etc.

[0011] The printer section 100 is provided with an image forming unit having five imaging units 18S, 18Y, 18M, 18C, and 18K for forming images of each color of special color (S), yellow (Y), magenta (M), cyan (C), and black (K). The subscripts S, Y, M, C, and K added after the numbers of each reference symbol indicate that the unit is for the special color, yellow, cyan, magenta, or black (hereinafter the same). In addition to the imaging units 18S, 18Y, 18M, 18C, and 18K, an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer device 400, a pair of registration rollers 49, and a fixing device 25 using a belt fixing method are provided.

[0012] The optical writing unit 21 includes a light source, a polygon mirror, an f-θ lens, a reflecting mirror, etc., and irradiates the surfaces of the photoconductors 1S, 1Y, 1M, 1C, and 1K with laser light based on image data.

[0013] The imaging units 18S, 18Y, 18M, 18C, and 18K each include a drum-shaped photoconductor 1S, 1Y, 1M, 1C, and 1K, as well as a charger, a developing device, a drum cleaning device, a static eliminator, and the like.

[0014] The imaging unit 18S for S (special color) will be described below. The surface of the photoreceptor 1S is uniformly charged by a charger serving as a charging means. The charged surface of the photoreceptor 1S is irradiated with laser light modulated and deflected by an optical writing unit 21. Then, the potential of the irradiated area (exposed area) is attenuated. Due to this attenuation, an S electrostatic latent image is formed on the surface of the photoreceptor 1S. The formed S electrostatic latent image is developed by a developing device serving as a developing means into an S toner image.

[0015] The S toner image formed on the S photoconductor 1S is primarily transferred onto the intermediate transfer belt 110. After the primary transfer, the surface of the photoconductor 1S is cleaned by a drum cleaning device to remove any residual toner remaining after transfer.

[0016] In the S imaging unit 18S, the photoconductor 1S cleaned by the drum cleaning device is discharged by the discharger. Then, the photoconductor 1S is uniformly charged by the charger and returned to its initial state. The above series of processes are the same for the other imaging units (18Y, 18M, 18C, 18K).

[0017] Next, the intermediate transfer unit will be described. The intermediate transfer unit 17 includes an intermediate transfer belt 110 and a belt cleaning device 90. It also includes a drive roller 15, a secondary transfer backup roller 16, and four primary transfer bias rollers 62S, 62Y, 62M, 62C, and 62K.

[0018] The endless intermediate transfer belt 110 is tensioned by a plurality of tension rollers, including a drive roller 15, disposed inside the loop of the intermediate transfer belt 110. The intermediate transfer belt 110 is moved endlessly in the clockwise direction in the drawing by the rotation of the drive roller 15, which is driven by a belt drive motor.

[0019] The four primary transfer bias rollers 62S, 62Y, 62M, 62C, and 62K are disposed so as to be in contact with the inner peripheral side of the intermediate transfer belt 110, and a primary transfer bias output from a power source is applied to each of the primary transfer bias rollers 62S, 62Y, 62M, 62C, and 62K. ... primary transfer bias presses the intermediate transfer belt 110 against the photoconductors 1S, 1Y, 1M, 1C, and 1K, respectively, to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photoconductor 1 and the primary transfer bias rollers 62 due to the influence of the primary transfer bias.

[0020] The S toner image formed on the S photoconductor 1S is primarily transferred onto the intermediate transfer belt 110 by the influence of the primary transfer electric field and nip pressure. The Y toner image, M toner image, C toner image, and K toner image formed on the Y, M, C, and K photoconductors 1Y, 1M, 1C, and 1K are sequentially superimposed and primarily transferred onto this S toner image. A multi-color toner image is formed on the intermediate transfer belt 110 by this superimposed primary transfer.

[0021] The multi-color toner images transferred and superimposed on the intermediate transfer belt 110 are secondarily transferred to a recording sheet in a secondary transfer nip, which will be described later. Residual toner remaining on the surface of the intermediate transfer belt 110 after passing through the secondary transfer nip is cleaned by a belt cleaning device 90 that sandwiches the belt between itself and a drive roller 15 on the left side of the drawing.

[0022] Next, the secondary transfer device 400 will be described. The secondary transfer device 400, disposed below the intermediate transfer unit 17 in the drawing, forms a secondary transfer nip by bringing a secondary transfer roller 407 into contact with the portion of the intermediate transfer belt 110 where the secondary transfer backup roller 16 is wound around it. A secondary transfer bias of the same polarity as the toner is applied to the secondary transfer backup roller 16, while the secondary transfer roller 407 is grounded. As a result, a secondary transfer electric field is formed in the secondary transfer nip, which electrostatically moves the multi-color toner image on the intermediate transfer belt 110 from the belt side toward the secondary transfer roller 407 side. The multi-color toner image, influenced by the secondary transfer electric field and nip pressure, is secondarily transferred onto a recording sheet fed into the secondary transfer nip by a pair of registration rollers 49 in synchronization with the multi-color toner image on the intermediate transfer belt 110.

[0023] The paper feed device 200 provided at the bottom of the copying machine body is provided with a paper feed cassette 44 and a paper bank 43 that store a plurality of recording sheets stacked together in a sheet bundle. The paper feed cassette 44 and the paper bank 43 press a paper feed roller 42 against the topmost recording sheet of the paper bundle. The topmost recording sheet is sent toward the paper feed path 46 by rotating the paper feed roller 42.

[0024] The paper feed path 46, which receives the recording sheets sent from the paper feed cassette 44 or the paper bank 43, has a plurality of conveying roller pairs 47 and a registration roller pair 49 provided near the end of the path. The recording sheets are conveyed toward the registration roller pair 49. The recording sheets conveyed toward the registration roller pair 49 are sandwiched between the rollers of the registration roller pair 49. Meanwhile, in the intermediate transfer unit 17, the multi-color toner image formed on the intermediate transfer belt 110 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the recording sheet sandwiched between the rollers at a timing that allows the recording sheet to be brought into contact with the multi-color toner image at the secondary transfer nip. As a result, the multi-color toner image on the intermediate transfer belt 110 is brought into contact with the recording sheet at the secondary transfer nip. Then, the recording sheet is secondarily transferred onto the recording sheet, becoming a full-color image on the white recording sheet. The recording sheet on which the full-color image has been formed in this manner leaves the secondary transfer nip as the secondary transfer roller 407 is rotated, and is then sent to the fixing device 25 via a sheet transport unit equipped with a transport belt.

[0025] The fixing device 25 includes a belt unit that moves the fixing belt 26 endlessly while stretching it between two rollers, and a pressure roller 27 that is pressed against one of the rollers of the belt unit. The fixing belt 26 and the pressure roller 27 come into contact with each other to form a fixing nip, and a recording sheet received from the sheet transport unit is sandwiched in the fixing nip. Of the two rollers in the belt unit, the roller that is pressed by the pressure roller 27 has an internal heat source that generates heat to pressurize the fixing belt 26. The pressed fixing belt 26 heats the recording sheet sandwiched in the fixing nip. Due to the effect of this heat and nip pressure, a full-color image is fixed to the recording sheet.

[0026] The recording sheet which has been subjected to the fixing process in the fixing device 25 is either stacked on a stack section protruding from the left side panel of the copier housing in the figure, or returned to the secondary transfer nip to form a toner image on the other side as well.

[0027] When copying an original, for example, a stack of sheet originals is set on the original table 30 of the automatic original feeder 600. However, if the original is a single-sided bound original that is closed like a book, it is set on the contact glass 32. Prior to this setting, the automatic original feeder 600 is opened relative to the copying machine body, and the contact glass 32 of the scanner 300 is exposed. After this, the single-sided bound original is pressed down by the closed automatic original feeder 600.

[0028] After the document is set in this manner, when the copy start switch is pressed, the document reading operation by the scanner 300 starts. However, if a sheet document is set in the automatic document feeder 600, the automatic document feeder 600 automatically conveys the sheet document to the contact glass 32 prior to the document reading operation. In the document reading operation, first, the first traveling body 33 and the second traveling body 34 both start traveling, and light is emitted from a light source provided in the first traveling body 33. Then, the reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, passes through an imaging lens 35, and is then incident on the reading sensor 36. The reading sensor 36 constructs image information based on the incident light.

[0029] In parallel with this document reading operation, the devices in each image-forming unit (18S, 18Y, 18M, 18C, 18K), the intermediate transfer unit 17, the secondary transfer device 400, and the fixing device 25 each start to operate. Then, based on the image information constructed by the reading sensor 36, the optical writing unit 21 is controlled and driven to form S, Y, M, C, and K toner images on the photoconductors 1S, 1Y, 1M, 1C, and 1K. These toner images are transferred onto the intermediate transfer belt 110 in a superimposed manner to form a multi-color toner image.

[0030] Almost simultaneously with the start of the document reading operation, a paper feed operation is started in the paper feed device 200. In this paper feed operation, one of the paper feed rollers 42 is selectively rotated to feed a recording sheet from the paper bank 43 or the paper feed cassette 44. The fed recording sheets are separated one by one by the separation roller 45 and enter the reversing paper feed path, and then are transported by the transport roller pair toward the secondary transfer nip.

[0031] In the copying machine according to the embodiment, when a multi-color image made of toners of two or more colors is formed, the intermediate transfer belt 110 is stretched in such a manner that its upper stretch surface is almost horizontal, and all the photoconductors (1S, 1Y, 1M, 1C, 1K) are brought into contact with the upper stretch surface. In contrast, when a monochrome image made of only K toner is formed, the intermediate transfer belt 110 is tilted downward and to the left in the figure, and its upper stretch surface is separated from the photoconductors 1S, 1Y, 1M, 1C for S, Y, M, and C. Then, of the five photoconductors 1S, 1Y, 1M, 1C, 1K, only the photoconductor 1K for K is rotated counterclockwise in the figure to form only a K toner image. At this time, not only the photoconductors 1 but also the developing device 4 are stopped for S, Y, M, and C to prevent unnecessary consumption of the photoconductors 1 and the developer.

[0032] A control unit consisting of a CPU and the like that controls the following devices inside the copier is disposed inside the housing of the copier. An operation display unit 500 consisting of a liquid crystal display, various key buttons, etc. is disposed on the top surface of the housing. An operator can specify a single-sided print mode in which an image is formed on only one side of a recording sheet, a double-sided print mode in which an image is formed on both sides, etc., by sending a command to the control unit through key input operation on this operation display unit 500.

[0033] 2 to 4 are schematic diagrams of the secondary transfer device 400, and Fig. 2 is a schematic diagram of the secondary transfer device 400 viewed from the left-right direction (X direction) of the device. Fig. 3 is a schematic diagram of the front side of the secondary transfer device (a schematic diagram of the front side viewed from the rear side (+Y direction)), and Fig. 4 is a schematic diagram of the rear side of the secondary transfer device (a schematic diagram of the rear side viewed from the front side). In the following explanation, the vertical direction is the Z direction, the front-rear direction of the device is the Y direction, and the left-right direction of the device is the X direction. FIG. 2 also shows the secondary transfer device 400 (drawer unit 70) in a non-attached state after being drawn out from the main body of the copier.

[0034] The secondary transfer device 400 has a secondary transfer unit 40 as a unit, and a drawer unit 70 as a unit support device that rotatably supports the secondary transfer unit 40. The drawer unit 70 is supported by the copier body so as to be able to be drawn out toward the front side of the copier body (X direction).

[0035] The secondary transfer unit 40 has six tension rollers that support the secondary transfer belt 406 on the inner peripheral side of the belt. Specifically, the six tension rollers are a secondary transfer roller 407, a separation roller 401, driven rollers 402 and 403, a drive roller 404, and a slippage prevention roller 409. It also has a tension roller 405 that presses the secondary transfer belt 406 from the outer peripheral surface. The multiple tension rollers that tension the secondary transfer belt 406 are rotatably supported by a pair of roller support plates 40a and 40b as roller support members. The secondary transfer unit 40 may also include a cleaning member, a lubricant application device, and the like.

[0036] The drawer unit 70 is provided with pressure arms 72a and 72b as a pair of pressure members that come into contact with a core metal part 407a that rotatably supports the secondary transfer roller 407. These pressure arms 72a and 72b are provided on the inner side in the front-rear direction (Y direction) of the device than the side plates 170a and 170b of the frame 170 of the drawer unit 70.

[0037] The pressure arm 72b on the rear side of the apparatus is rotatably supported by a rear cylindrical shaft 413b serving as a support provided on the rear side plate 170b of the frame 170. The pressure arm 72a on the front side of the apparatus is rotatably supported by a front cylindrical shaft 413a serving as a support provided on the front side plate 170a.

[0038] The drawer unit 70 has a first pressure drive device 78a (see FIG. 3) that rotates the pressure arm 72a on the front side of the device, and a second pressure drive device 78b (see FIG. 4) that rotates the pressure arm 72b on the rear side of the device. The first pressure drive device 78a and the second pressure drive device 78b have the same configuration. The pressure motor 71, which is a stepping motor that is an electric motor of each pressure drive device, is disposed near the center in the axial direction, and the driving force of the pressure motor 71 is transmitted to a pressure cam 74, which is a cam member, via a timing belt 75. The pressure cam 74 abuts against a cam receiving roller 73a provided near the lower part of the pressure arm 72 on the opposite side to the support shaft side. The pressure cam 74 is attached to a cam shaft that is rotatably supported by a frame 170.

[0039] 3 and 4, the cam receiving roller 73a is supported by the pressure arm 72 so as to be movable within a predetermined range in the vertical direction of the device (Z direction). The pressure arm 72 is provided with a pressure spring 73b, one end of which abuts against a spring receiving portion 73c of the pressure arm 72 and the other end of which abuts against a bearing portion 73d that supports the shaft of the cam receiving roller 73a.

[0040] The tips of the front cylindrical shaft 413a and the rear cylindrical shaft 413b have arc-shaped grooves 426, 427 formed by cutting out, which serve as support parts for positioning and supporting the shaft member 412, which serves as the supported part of the secondary transfer unit 40. By positioning and supporting the shaft member 412 of the secondary transfer unit 40 in the grooves 426, 427 of the cylindrical shafts 413a, 413b, the center of rotation of the secondary transfer unit 40 and the center of rotation of the pressure arm 72 can be aligned with high precision.

[0041] In addition, the secondary transfer unit 40 is positioned and supported by the abutment portions 172a of the pressure arms 72a and 72b as both ends of the core metal portion 407a, which rotatably supports the secondary transfer roller 407, come into contact with the abutment portions 172a of the pressure arms 72a and 72b. In this manner, the secondary transfer unit 40 is positioned and supported in the drawer unit 70 by the abutment portions 172a of the pressure arms 72a and 72b and the cylindrical shafts 413a and 413b.

[0042] In this embodiment, various types of recording sheets are used, such as plain paper, thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and OHP sheets. The optimal secondary transfer pressure (nip pressure) differs depending on the type of recording sheet. Therefore, in this embodiment, the secondary transfer pressure is adjusted according to the type of recording sheet. For example, the user operates the operation display unit 500 (see FIG. 1) provided in the main body of the copier to input type information of the recording sheets set in the paper bank 43 and the paper feed cassette 44. The control unit of the copier sets the driving time of the pressure motor 71 based on the input type information of the recording sheets. Specifically, the pressure motor 71 is a stepping motor, and sets the number of steps based on the input type information of the recording sheets.

[0043] By driving the pressure motor 71 for a set number of steps, the position in the rotation direction of the pressure cam 74 that contacts the cam receiving roller 73a corresponds to the type of recording sheet, and the pressure applied to the core metal portion 407a of the pressure arm 72 is adjusted to correspond to the type of recording sheet. As a result, the force applied to the secondary transfer nip is adjusted to a force corresponding to the type of recording sheet, resulting in a secondary transfer pressure corresponding to the type of recording sheet.

[0044] Furthermore, by using a stepping motor as the pressure motor 71, a holding force (holding torque) can be generated by passing a constant current through the motor in a stopped state. This motor holding force can prevent the pressure cam 74 from rotating in a direction that reduces the pressure force (secondary transfer pressure) due to the reaction force from the intermediate transfer belt 110 (secondary transfer backup roller 16) or the weight of the secondary transfer unit. This allows the pressure cam 74 to be stopped at a position corresponding to the type of recording sheet without using an electromagnetic brake or the like, reducing the number of parts and the cost of the device.

[0045] When the recording sheet enters the secondary transfer nip, the pressure spring 73b contracts, the secondary transfer unit 40 rotates together with the pressure arm 72 in the clockwise direction in FIG. 3, and the secondary transfer unit 40 retreats (moves in a direction away from the intermediate transfer belt 110) by the thickness of the recording sheet. This allows the recording sheet to pass through the secondary transfer nip.

[0046] Two front positioning shafts 203 are formed on the upper part of the front side plate 170a of the frame 170. The front side of the secondary transfer device 400 is positioned by inserting these front positioning shafts 203 into positioning holes provided in the front side plate of the copier body.

[0047] Two rear positioning shafts 416 are also formed on the upper part of the rear side plate 170b of the frame 170. The rear side of the secondary transfer device 400 is positioned by inserting these rear positioning shafts 416 into positioning holes 102e provided in the main body rear side plate 102 (see FIG. 2) of the copier main body.

[0048] An opening for pulling out the secondary transfer device 400 (drawer unit 70) is provided on the front side of the copier body. An opening door is provided at the opening, and when pulling out the secondary transfer device 400 from the copier body, the opening door is opened to open the opening. This makes it possible to pull out the secondary transfer device 400 from the opening. With the secondary transfer device 400 pulled out from the opening in the X direction, the secondary transfer unit 40 is detachable in the Z direction (vertical direction) from the drawer unit 70.

[0049] As shown in Fig. 2, the drawer unit 70 has a fixing mechanism 130 for fixing the rear side of the shaft member 412 to the groove portion 427 serving as a support portion of the cylindrical shaft 413b serving as a support member so as not to be detachable. The fixing mechanism 130 has a slide member 133 held by the rear side plate 170b of the frame 170 so as to be slidable in the Y direction. The slide member 133 has a first plate 133a that is perpendicular to the Y direction and faces the inner surface of the rear side plate 170b, a second plate 133c that faces the outer surface of the rear side plate 170b, and four legs 133b that connect the first plate 133a and the second plate 133c. The legs 133b are connected to the four corners of the plates 133a and 133c, respectively.

[0050] The first face plate 133a has a through hole through which the rear cylindrical shaft 413b passes. A fixed base 132 to which one end of a leaf spring member 131 serving as a pressing member is fixed is provided on the surface of the first face plate 133a opposite to the surface facing the rear side plate 170b. One end of the leaf spring member 131 is fixed to the tip of the fixed base 132.

[0051] Each leg portion 133b holds a coil spring 134 serving as a biasing means. Each leg portion 133b is inserted into each coil spring 134 to support the coil spring 134. One end of the coil spring 134 abuts against the second panel 133c, and the other end abuts against the rear side panel 170b.

[0052] As shown in FIG. 4, a notch for allowing the fixed base 132 to escape is formed in the rear cylindrical shaft 413b and in the through hole of the rear pressure arm 72b through which the cylindrical shaft 413b passes.

[0053] 2, when the secondary transfer device 400 (drawer unit 70) is drawn out from the main body of the copier, the leaf spring member 131 is located at a retracted position retracted in the Y direction from the shaft member 412 (where the leaf spring member does not face the shaft member in the Z direction) by the biasing force of the coil spring 134. As a result, the leaf spring member 131 does not hinder the attachment and detachment of the secondary transfer unit 40 to and from the drawer unit 70.

[0054] FIG. 5 is a schematic diagram showing the secondary transfer device 400 mounted in the main body of a copying machine. When the secondary transfer device 400 (drawer unit 70) is pushed into the main body of the copier from the state shown in FIG. 2, the rear positioning shaft 416 is inserted into the positioning hole 102e of the main body rear panel 102 of the copier main body, as shown in FIG. 5, and the rear side of the secondary transfer device 400 is positioned.

[0055] Furthermore, the second plate 133c of the slide member 133 abuts against the main body rear side plate 102. When the secondary transfer device 400 (drawer unit 70) is further pushed into the main body of the copier from this state, the slide member 133 slides toward the front side relative to the drawer unit 70 against the biasing force of the coil spring 134 (see arrow D in FIG. 5).

[0056] The rear end of the shaft member 412 has a tapered shape (cone shape) so that the diameter becomes shorter toward the end. When the slide member 133 slides toward the front side relative to the drawer unit 70, the abutment portion of the leaf spring member 131 abuts against the tapered rear end of the shaft member 412 and climbs up the rear end. This causes the leaf spring member 131 to elastically deform and exert a biasing force.

[0057] 5, when the secondary transfer device 400 is attached to the main body of the copier, the leaf spring member 131 is located at a pressing position where it presses the shaft member 412 into the groove portion 427. As a result, the leaf spring member 131 presses the shaft member 412 into the arc-shaped groove portion 427 of the rear cylindrical shaft 413b, and the shaft member 412 is fixed to the rear cylindrical shaft 413b so as not to be detached.

[0058] The shaft member 412 is pressed by the leaf spring member 131 into the groove portion 427 serving as a support portion and fixed thereto, so that the shaft member 412 can be fixed to the groove portion 427 without rattling. This allows the rear side of the shaft member 412 to be positioned with high precision in the Z direction (vertical direction) and the X direction (left-right direction of the device). In addition, the front side of the shaft member 412 is positioned in the X direction by fitting into the arc-shaped groove portion 426 of the front cylindrical shaft 413a. By positioning the shaft member 412 on the cylindrical shafts 413a and 413b, the center of the shaft member 412, which is the rotation center of the secondary transfer unit, can be satisfactorily aligned with the centers of the cylindrical shafts 413a and 413b, which are the rotation centers of the pressure arms 72a and 72b.

[0059] In addition, by pushing the secondary transfer device 400 (drawer unit 70) into the main body of the copier, the rear side of the shaft member 412 can be automatically fixed to the cylindrical shaft 413b serving as the support member. This simplifies the work of mounting the secondary transfer unit 40 to the drawer unit 70, compared to a case in which the rear side of the shaft member 412 is manually fixed before pushing the secondary transfer device 400 (drawer unit 70) into the main body of the copier.

[0060] When the secondary transfer device 400 is pulled out from the body of the copier, the urging force of the coil spring 134 moves the slide member 133 rearward, and the leaf spring member 131 is automatically positioned at the retracted position shown in FIG. 2. This automatically releases the rear side of the shaft member 412 from the cylindrical shaft 413b, making it detachable. Therefore, the secondary transfer unit can be removed from the drawer unit simply by pulling the secondary transfer device 400 out of the body of the copier. This simplifies the removal work of the secondary transfer unit 40 from the drawer unit 70, compared to a case in which the shaft member 412 is manually brought into a detachable state from the cylindrical shaft 413b when removing the secondary transfer unit 40 from the drawer unit 70.

[0061] Next, a modification of this embodiment will be described.

[0062] [Variation 1] Figure 6 is a schematic diagram of variant example 1, where Figure 6(a) shows the secondary transfer device 400 pulled out from the copier body, and Figure 6(b) shows the secondary transfer device 400 attached to the copier body.

[0063] This modified example 1 has positioning plates 201 and 202 that serve as position fixing members for fixing the relative positions of the secondary transfer device 400 and the intermediate transfer unit 17. The rear positioning panel 202 is provided on the main body rear panel 102. The rear positioning panel 202 is provided with two panel positioning holes 205, into which the rear ends of two reference shafts 316 provided in the intermediate transfer unit 17 are respectively inserted, spaced apart at a predetermined interval in the left-right direction (X direction) of the device.

[0064] The rear positioning face plate 202 is provided with two positioning holes 206 into which two rear positioning shafts 416 are respectively inserted. The two rear positioning shafts 416 are provided at a predetermined interval in the X direction on the rear side plate 170b of the frame 170 of the drawer unit 70.

[0065] The rear positioning panel 202 is supported so as to be displaceable (movable) along a plane (XZ plane) perpendicular to the front-to-rear direction (Y direction) of the device relative to the main body rear plate 102 of the copier main body. Specifically, small diameter portions of multiple stepped studs 102a provided on the main body rear plate 102 are inserted into support holes 202a provided in the rear positioning panel 202 corresponding to each stud 102a, thereby supporting the rear positioning panel 202 on the main body rear plate 102. Then, the rear positioning panel 202 is attached to the main body rear plate 102 by screwing screws 207 into the studs 102a.

[0066] The inner diameter of the support hole 202a provided in the rear positioning panel 202 is larger than the diameter of the small diameter portion of the stud 102a. The length (length in the Y direction) of the small diameter portion of the stud 102a is also longer than the plate thickness of the rear positioning panel 202. Therefore, the screw 207 is screwed into the stud with a predetermined gap between the head of the screw and the rear positioning panel 202. As a result, the rear positioning panel 202 is supported relative to the main body rear panel 102 so as to be displaceable (movable) along a plane (XZ plane) perpendicular to the front-rear direction (Y direction) of the device.

[0067] The reference shaft 316 of the intermediate transfer unit is inserted into the plate positioning hole 205 of the rear positioning plate 202, thereby positioning the rear positioning plate 202 with respect to the intermediate transfer unit 17. Then, the rear positioning shaft 416 provided on the rear side plate 170b of the frame 170 is inserted into the rear positioning hole 206 of the rear positioning plate 202 that has been positioned with respect to the intermediate transfer unit 17. This determines the relative positions of the secondary transfer device 400 and the intermediate transfer unit 17 on the rear side.

[0068] The front positioning panel 201 is attached to the reference shaft 315 of the intermediate transfer unit 17 and the front positioning shaft 203 of the secondary transfer device 400 without being supported by the main body of the copier. This determines the relative positions of the secondary transfer device 400 and the intermediate transfer unit 17 on the front side. Furthermore, since the front positioning panel 201 is not supported by the main body of the copier, the front positioning panel 201 is also supported so as to be displaceable along the XZ plane with respect to the device main body.

[0069] The following advantages can be obtained by supporting the front positioning plate 201 and the rear positioning plate 202 so as to be displaceable along the XZ plane with respect to the device body. That is, the pressure force of the secondary transfer roller 407 on the intermediate transfer belt 110 can be made an internal force of the integrated unit consisting of the secondary transfer device 400 and the intermediate transfer unit 17. This prevents the above pressure force from being applied to the main body of the copier, and suppresses deformation of members such as the housing of the main body of the copier, such as the main body rear side plate 102. This has the advantage of suppressing changes in the positional relationship of members within the device and suppressing effects on image quality. In addition, there is no need to increase the strength of members such as the housing of the main body of the copier so as not to deform due to the pressure force of the secondary transfer device 400, which has the advantage of reducing the cost of the device.

[0070] [Variation 2] FIG. 7 is a schematic configuration diagram of a main part of the second modified example. As shown in Fig. 7, in this modification 2, the pressing member for pressing the shaft member 412 against the groove portion 427 serving as a support portion is a plate-like member 135 supported at one end by the fixed base 132. The lower surface of the plate-like member 135 has a sliding protrusion 135a serving as a sliding portion that slides against the shaft member 412, and a pressing protrusion 135b serving as a pressing portion that presses the shaft member 412 against the groove portion 427. The sliding protrusion 135a is provided at the tip of the plate-like member 135, and is higher from the lower surface of the plate-like member 135 than the pressing protrusion 135b. In addition, the sliding protrusion 135a is made of a member having a higher slidability with respect to the shaft member 412 than the pressing protrusion 135b.

[0071] Further, on the rear side of the shaft member 412, there is formed a retraction groove 412a into which the sliding protrusion 135a fits when the secondary transfer device 400 is mounted in the copying machine body.

[0072] When the secondary transfer device 400 (drawer unit 70) is pushed into the main body of the copier and the slide member 133 moves relatively forward with respect to the secondary transfer device 400, the sliding protrusion 135a protruding from the lower surface of the plate-like member further than the pressing protrusion 135b comes into contact with the shaft member 412. As a result, the plate-like member 135 is elastically deformed so that the tip of the plate-like member 135 moves upward.

[0073] 7(b), the sliding protrusion 135a moves toward the front while sliding against the outer circumferential surface of the shaft member 412. At this time, the pressing protrusion 135b, which is shorter than the sliding protrusion 135a, does not come into contact with the shaft member 412.

[0074] When the secondary transfer device 400 is attached to the copier body and the plate-like member 135 is located at the pressing position, the sliding protrusion 135a enters the retraction groove 412a as shown in FIG. 7(c). As a result, the tip of the plate-like member 135 moves downward. Then, the pressing protrusion 135b comes into contact with the shaft member 412 and presses the rear side of the shaft member 412 into the groove portion 427. As a result, the rear side of the shaft member 412 is fixed to the cylindrical shaft 413b serving as a support member.

[0075] In the second modification, sliding between the pressing protrusion 135b and the shaft member 412 is suppressed, and wear of the pressing protrusion 135b can be suppressed. This makes it possible to suppress a decrease in the pressing force over time, and the rear side of the shaft member 412 can be satisfactorily fixed to the cylindrical shaft 413b over time.

[0076] [Variation 3] Figure 8 is a schematic diagram of the main parts of variant example 3, where Figure 8(a) shows the secondary transfer device 400 pulled out from the copier body, and Figure 8(b) shows the secondary transfer device 400 attached to the copier body. In this third modification, a support member 136 having a support hole 136a as a support portion into which a shaft member 412 is inserted to support the shaft member 412 is provided on a slide member 133. The support hole 136a serves as a support portion into which a shaft member 412 is inserted.

[0077] The support member 136 is made of sheet metal, with a tip bent downward by 90 degrees, and a support hole 136a is formed in the bent portion. A sliding member is provided on the inner peripheral surface of the support hole 136a. The support member 136 is also provided with an elastic member 136b made of an elastic material such as rubber as a pressing member for pressing the shaft member 412 against the support hole 136a.

[0078] The rear cylindrical shaft 413b is provided with a temporary support portion 414 that temporarily supports the rear side of the shaft member 412 when the secondary transfer device 400 is pulled out from the main body of the copier. The temporary support portion 414 may be omitted. This is because when the secondary transfer unit 40 is pulled out from the main body of the copier, both ends of the core metal portion 407a are supported by the pressure arms 72a and 72b, and the front side of the shaft member 412 is supported by the front cylindrical shaft 413a, so that the secondary transfer unit 40 is supported at three points. Therefore, even without the temporary support portion 414, the secondary transfer unit 40 can be supported by the drawer unit 70 in the pulled out state with almost no change in its posture.

[0079] 7A, when the secondary transfer device 400 is pulled out from the main body of the copier, the support hole 136a is located at the non-support position, and the rear side of the shaft member 412 is removed from the support hole 136a. At this time, the rear side of the shaft member 412 is temporarily supported by the temporary support portion 414. In this way, when the secondary transfer device 400 is pulled out from the main body of the copier, the rear side of the shaft member 412 is removed from the support hole 136a, the fixation is released, and the secondary transfer unit 40 is in a removable state. Therefore, the secondary transfer unit 40 can be removed from the pull-out unit 70 by moving the secondary transfer unit 40 vertically upward.

[0080] When the secondary transfer device 400 is pushed into the copier body, the slide member 133 abuts against the main body rear side plate 102 in the same manner as described above, and slides toward the front side relative to the drawer unit 70 against the biasing force of the coil spring 134. As the slide member 133 slides toward the front side, the rear side of the shaft member 412 is inserted into the support hole 136a of the support member 136, and the rear side of the shaft member 412 is supported by the support hole 136a.

[0081] When the secondary transfer device 400 is attached to the copier body, the support member 136 is located at the support position, and the elastic member 136b, which is a pressing member protruding from the lower surface, comes into contact with the rear side of the shaft member 412 and presses the rear side of the shaft member 412 downward. As a result, the rear side of the shaft member 412 is pressed against the lower part of the support hole 136a, and the rear side of the shaft member 412 is fixed to the support hole 136a without any rattling.

[0082] In this modification 3, the rear side of the shaft member 412 is automatically fixed by pushing the secondary transfer device 400 (drawer unit 70) into the main body of the copier. This simplifies the work of mounting the secondary transfer unit 40 to the drawer unit 70, compared to a case in which the rear side of the shaft member 412 is manually fixed before pushing the secondary transfer device 400 (drawer unit 70) into the main body of the copier.

[0083] 8(b), the sliding member 133 moves rearward relative to the drawer unit 70 due to the biasing force of the coil spring 134, and the rear side of the shaft member 412 comes out of the support hole 136a. This automatically releases the rear side of the shaft member 412, making it removable. This simplifies the removal work of the secondary transfer unit 40 from the drawer unit 70, compared to a case in which the shaft member 412 is manually released from its fixed state to make it removable after the secondary transfer device 400 is pulled out of the copier body.

[0084] In the configuration in which the rear side of the shaft member 412 is positioned and fixed by pressing the shaft member 412 against the groove portion 427 of the cylindrical shaft 413b, the shaft member 412 needs to be pressed from vertically above due to the attachment / detachment direction of the secondary transfer unit 40 with respect to the drawer unit 70. However, as shown in Modification 3, in the configuration of Modification 3 in which the rear side of the shaft member 412 is positioned and fixed by inserting the shaft member 412 into the support hole 136a and pressing the shaft member 412 against the inner circumferential surface of the support hole 36a, for example, a configuration as shown in FIG. 9 can be used. That is, the rear side of the shaft member 412 is fixed by pressing the shaft member 412 from the X direction (the left-right direction of the device) by the elastic member 136b. In this way, since there is no restriction on the direction in which the shaft member 412 is pressed, the degree of freedom of layout can be improved.

[0085] On the other hand, the configuration in which the shaft member 412 is pressed against the groove portion 427 of the cylindrical shaft 413b to position and fix the rear side of the shaft member 412 has the advantage that there is no stacking tolerance and the rotation center of the pressure arm 72b and the rotation center of the secondary transfer unit can be easily and accurately aligned.

[0086] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description.

[0087] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) In a unit supporting device such as a drawer unit 70 having a support member such as a cylindrical shaft 413b that supports a supported part such as an axis member 412 of a unit such as a secondary transfer unit 40 and that is arranged to be able to be pulled out from the device main body, the unit supporting device is provided with a fixing mechanism 130 that fixes the supported part of the unit so that it cannot be removed when the unit supporting device is attached to the device main body, and switches from a non-detachable state to a detachable state in conjunction with the pulling operation of the unit supporting device from the device main body. According to this, by pulling out the unit support device from the device body, the supported part of the unit switches from a fixed state that cannot be detached to a detachable state. This makes it possible to detach the unit after pulling out the unit without performing work such as removing / attaching fixed members such as the rotating shaft support arm, and improves the ease of attaching and detaching the unit to and from the unit support device compared to Patent Document 1.

[0088] (Aspect 2) In aspect 1, the fixing mechanism 130 includes a pressing member such as a leaf spring member 131 that presses a supported portion such as the shaft member 412 against a supporting portion such as the groove portion 427 of a supporting member such as the cylindrical shaft 413b when a unit supporting device such as the drawer unit 70 is attached to the device main body. According to this, by pressing the supported portion such as shaft member 412 against a supporting portion such as groove portion 427 with a pressing member such as leaf spring member 131, the supported portion can be fixed without rattling, and deterioration of positional accuracy can be suppressed.

[0089] (Aspect 3) In aspect 1 or 2, the fixing mechanism 130 has a sliding member 133 that holds a pressing member such as a leaf spring member 131 and is slidable in the pull-out direction relative to the device body of the unit support device, and a biasing means such as a coil spring 134 that biases the sliding member 133 upstream in the pull-out direction, and when the unit support device is attached to the device body, the sliding member 133 abuts against a member of the device body such as the main body rear side plate 102 and is located at a pressing position where the pressing member presses the supported part against the supporting part, and in conjunction with the pull-out operation of the unit support device from the device body, the sliding member 133 slides upstream in the pull-out direction due to the biasing force of the biasing means, and moves to a retracted position where the pressing member is retracted from the supported part. According to this, as described in the embodiment, when a unit support device such as the drawer unit 70 is inserted into the apparatus body, the pressing member of the leaf spring member 131 is located at the pressing position, and the supported portion such as the shaft member 412 is pressed against a supporting portion such as the groove portion 427 of the supporting member such as the cylindrical shaft 413b, thereby fixing the supported portion so that it cannot be detached. Then, when the unit support device is pulled out from the apparatus body, the pressing member slides upstream in the pulling direction by the biasing force of the biasing means such as the coil spring 134 and moves to the retracted position. As a result, the state automatically switches from the non-detachable state to the detachable state in conjunction with the pulling operation of the unit support device from the apparatus body, and the ease of attachment and detachment of a unit such as the secondary transfer unit 40 to the unit support device can be improved.

[0090] (Aspect 4) In aspect 3, the pressing member such as plate-like member 135 has a pressing portion such as pressing protrusion 135b that abuts against a supported portion such as shaft member 412 and presses the supported portion when in the pressing position, and a sliding portion such as sliding protrusion 135a that slides against the supported portion and moves the pressing portion away from the supported portion when slide member 133 slides between the pressing position and the retracted position. As described in the second modification, this suppresses the sliding of the pressing portion, such as pressing protrusion 135b, with the supported portion, such as shaft member 412, and suppresses wear of the pressing portion. This suppresses a decrease in pressing force over time, and the supported portion can be favorably fixed to a supporting portion, such as groove 427 of a supporting member, such as cylindrical shaft 413b, over time.

[0091] (Aspect 5) In aspect 1, the support member 136 has a support hole 136a into which a supported part such as the shaft member 412 is inserted, and has a slide member 133 that holds the support member 136 and is slidable in the pull-out direction relative to the device body of a unit support device such as the drawer unit 70, and a biasing means such as a coil spring 134 that biases the slide member 133 upstream in the pull-out direction, and when the unit support device is attached to the device body, the slide member 133 is located at a support position where the supported part is inserted into the support hole 136a, and slides upstream in the pull-out direction due to the biasing force of the biasing means in conjunction with the pull-out operation of the unit support device from the device body, and the supported part moves to a non-support position where it has come out of the support hole 136a. According to this, as described in the third modification, when a unit support device such as the drawer unit 70 is attached to the apparatus body, the supported portion such as the shaft member 412 is inserted into the support hole 136a, and the supported portion is fixed to the support hole in an undetachable manner. When the unit support device is drawn out from the apparatus body, the supported portion slides upstream in the drawing direction due to the biasing force of the biasing means such as the coil spring 134, and the supported portion comes out of the support hole 136a, and the fixation is released and the unit becomes detachable. As a result, the unit support device automatically switches from an undetachable state to a detachable state in conjunction with the drawing operation of the unit support device from the apparatus body, and the ease of attachment and detachment of units such as the secondary transfer unit 40 to the unit support device can be improved.

[0092] (Aspect 6) In the fifth aspect, the support member 136 has a pressing member such as the elastic member 136b that presses the supported portion such as the shaft member 412 against the inner circumferential surface of the support hole 136a when the support member 136 is located at the support position. According to this, as described in the third modification, the supported portion such as the shaft member 412 can be fixed in the support hole 136a without rattling, and deterioration of positional accuracy can be suppressed. Furthermore, as described in the third modification, by configuring the supported portion to be fixed by inserting it into the support hole 136a, there is no restriction on the direction in which the pressing member presses the supported portion, thereby improving the freedom of layout.

[0093] (Aspect 7) In an image forming apparatus equipped with a transfer unit such as a secondary transfer unit 40 and a unit support device such as a drawer unit 70 that supports the transfer unit and is arranged so as to be able to be drawn out from the apparatus main body, the unit support device according to any one of aspects 1 to 6 was used as the unit support device. According to this, as described in the embodiment, the attachment and detachment operation of a transfer unit such as the secondary transfer unit 40 to and from a unit supporting device such as the drawer unit 70 can be simplified.

[0094] (Aspect 8) In aspect 7, there is provided an image carrier unit such as intermediate transfer unit 17 having an image carrier such as intermediate transfer belt 110 against which a transfer member such as secondary transfer roller 407 of a transfer unit such as secondary transfer unit 40 abuts, and a position fixing member such as positioning panel 202 that fixes the relative position with respect to the transfer unit, and the position fixing member is supported on the device body so as to be displaceable along a surface perpendicular to the pull-out direction. According to this, as described in the first modification, the pressure of the transfer member such as the secondary transfer roller 407 against the intermediate transfer belt can be the internal force of the unit consisting of the transfer device such as the secondary transfer device 400 and the intermediate transfer unit. This makes it possible to prevent the pressure force from being applied to the rear panel of the main body of the device, and to suppress deformation of members such as the housing of the main body of the copier. This makes it possible to suppress changes in the positional relationship of the members inside the device, and to suppress effects on image quality. In addition, it becomes unnecessary to increase the strength of members such as the housing of the main body of the copier, such as the rear panel 102, so as not to deform due to the pressure force of the transfer device, and the cost of the device can be reduced. [Explanation of symbols]

[0095] 16: Secondary transfer backup roller 17: Intermediate transfer unit 40: Secondary transfer unit 40a: Roller support plate 40b: Roller support plate 70: Drawer unit (unit support device) 71: Pressure motor 72: Pressure arm 73a: Cam receiving roller 73b: Pressure spring 73c: Spring support 73d: Bearing part 74: Pressure Cam 75: Timing belt 78a: First pressure drive device 78b: Second pressure drive device 102: Rear panel of main body 102a: Stud 102e: Positioning hole 110: Intermediate transfer belt 130:Fixing mechanism 131: Leaf spring member (pressure member) 132: Fixed base 133: Slide member 133a: First plate 133b: Legs 133c: Second face plate 134: Coil spring (biasing means) 135: Plate-shaped member (pressure member) 135a: Sliding protrusion (sliding portion) 135b: Pressing protrusion (pressing portion) 136: Support member 136a: Support hole 136b: Elastic member (pressure member) 170: Frame 170a: Front side panel 170b: Rear side plate 172a: Contact part 201: Front positioning face plate (position fixing member) 202: Rear positioning plate (position fixing member) 202a: Support hole 203: Front positioning axis 205: Face plate positioning hole 206: Rear positioning hole 207: Screw 316: Reference axis 400: Secondary transfer device 401: Separation roller 402: Driven roller 403: Driven roller 404: Drive roller 405: Tension roller 406: Secondary transfer belt 407: Secondary transfer roller 407a: Core metal part 409: Anti-slipping roller 412: Shaft member (supported part) 412a: Evacuation groove 413a: Front cylindrical shaft (support member) 413b: Rear cylindrical shaft (support member) 414: Temporary support 416: Rear positioning axis 426: Front groove (support part) 427: Rear groove (support part) [Prior art documents] [Patent documents]

[0096] [Patent Document 1] Patent No. 6260856

Claims

1. A unit support device has a support member that supports a supported portion of a unit and is provided so as to be removable from an apparatus main body, A unit support device characterized in that, when the unit support device is attached to the device main body, the supported portion of the unit is fixed so that it cannot be removed, and the unit support device is switched from the non-detachable state to a detachable state in conjunction with the pulling-out action of the unit support device from the device main body.

2. 2. The unit support device according to claim 1, The unit support device, wherein the fixing mechanism includes a pressing member that presses the supported portion against the supporting portion of the supporting member when the unit support device is attached to the apparatus body.

3. 3. The unit supporting device according to claim 2, the fixing mechanism includes a slide member that holds the pressing member and is slidable in a direction in which the unit support device is pulled out relative to the device body, and a biasing means that biases the slide member toward an upstream side in the pulling out direction, When the unit support device is attached to the device main body, the sliding member abuts against a member of the device main body and is positioned at a pressing position where the pressing member presses the supported portion against the supporting portion, and in conjunction with the pulling-out operation of the unit support device from the device main body, the sliding member slides upstream in the pulling-out direction due to the biasing force of the biasing means, and the pressing member moves to a retracted position where it is retracted from the supported portion.

4. The unit supporting device according to claim 3, The pressing member is a pressing portion that contacts the supported portion and presses the supported portion when the support member is at the pressing position; a sliding portion that slides against the supported portion when the sliding member slides between the pressing position and the retracted position, and moves the pressing portion away from the supported portion.

5. 2. The unit support device according to claim 1, the support member has a support hole into which the supported portion is inserted, a slide member that holds the support member and is slidable in a direction in which the unit support device is pulled out relative to the device body; a biasing means for biasing the slide member toward the upstream side in the pull-out direction, When the unit support device is attached to the device main body, the slide member is located at a support position where the supported part is inserted into the support hole, and in conjunction with the pulling-out operation of the unit support device from the device main body, the slide member slides upstream in the pulling-out direction due to the biasing force of the biasing means, so that the supported part moves to a non-support position where it has come out of the support hole.

6. The unit supporting device according to claim 5, The unit support device according to claim 1, wherein the support member has a pressing member that presses the supported portion against an inner circumferential surface of the support hole when the support member is located at the support position.

7. A transcription unit; an image forming apparatus including a unit support device that supports the transfer unit and is provided so as to be removable from an apparatus main body, 2. An image forming apparatus, comprising: the unit support device according to claim 1 as the unit support device.

8. 8. The image forming apparatus according to claim 7, an image carrier unit including an image carrier with which a transfer member of the transfer unit comes into contact, and a position fixing member that fixes a relative position with the transfer unit; The image forming apparatus according to claim 1, wherein the position fixing member is supported by the apparatus body so as to be displaceable along a plane perpendicular to a direction in which the transfer unit is pulled out.

Images