Transfer apparatus and image forming apparatus

Abstract

To speed up the attachment and detachment of a unit.SOLUTION: A transfer device has: a transfer unit 20 that has a belt member (intermediate transfer belt 2) and first holding members 1-1 to 1-4 for holding warped ends in a width direction of the belt member, and is detachably arranged with respect to an apparatus body in the width direction of the belt member; and functional members 2-1 to 2-5 that are detachably arranged with respect to the apparatus body in the width direction of the belt member while being adjacent to the belt member of the transfer unit 20. Second holding members 4-1 and 4-2 prevent the functional members from separating from the apparatus body. The first holding members 1-1 to 1-4 and the second holding members 4-1 and 4-2 can be moved to working positions and non-working positions by a common operation member 16, and the operation member 16 can be switched to a first switching position for selecting the non-working positions of the first holding members and the working positions of the second holding members, and a second switching position for selecting the working positions of the first holding members and the non-working positions of the second holding members.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0001] The present invention relates to a transfer device including a belt member for transporting a sheet member and an image forming apparatus including the same.

Background Art

[0002] An image forming apparatus includes a plurality of units having various functions related to image formation inside the apparatus main body. These plurality of units include a process cartridge unit and a transfer unit. The process cartridge unit is also abbreviated as a PCDU (Photo Conductor Development Unit).

[0003] The transfer unit has a belt member for transporting a sheet member. The PCDU forms an image on the sheet member and is usually composed of a plurality of units. These plurality of units can be composed of a total of five units, namely, four units using toners of yellow (Y), magenta (M), cyan (C), and black (K), and one unit using toners other than these (hereinafter referred to as "special toners").

[0004] Special toners include transparent toner, white toner, gold toner, and the like. A plurality of PCDUs using different special toners can be prepared, and one desired special toner can be selected and mounted on the apparatus main body.

[0005] Each unit is detachably arranged in the width direction of the belt member with respect to the apparatus main body for maintenance, cleaning, component replacement, unit replacement, etc. On the other hand, since the belt member of the transfer unit has a multilayer structure having a base layer and an elastic layer, etc., warping is likely to occur at the width direction ends of the belt due to thermal deformation or deterioration over time.

[0006] Since the transfer unit and the PCDU are adjacently arranged with a narrow gap therebetween, a part of the unit may be caught by the warping of the belt end during the attachment and detachment of the unit. Then, a crease remains on the belt, and this crease causes transfer defects or image defects.

[0007] Therefore, it has been proposed to place a belt retainer to suppress the curvature of the belt end (see, for example, Patent Document 1). This belt retainer is supported by an attachment / detachment mechanism, and by moving the belt retainer vertically with the attachment / detachment mechanism when attaching or detaching the unit, it is possible to prevent part of the unit from getting caught on the curvature of the belt end. [Overview of the project] [Problems that the invention aims to solve]

[0008] In devices with such a connecting / separating mechanism, a foolproof structure is provided that prevents the PCDU from being separated unless the connecting / separating mechanism is operated. This foolproof structure includes a PCDU retainer that prevents the PCDU from being separated. The PCDU retainer can be released by operating the connecting / separating mechanism.

[0009] However, the process of attaching and detaching the unit by sequentially operating the connecting / separating mechanism and the PCDU retainer is cumbersome and time-consuming. The present invention aims to solve this problem and expedite the attachment and detachment of the unit. [Means for solving the problem]

[0010] To solve the above problems, the present invention provides a transfer device comprising a transfer unit having a belt member for transporting a sheet member and a first pressing member for suppressing the curvature of the widthwise end of the belt member, wherein the transfer unit is detachably disposed to the device body in the widthwise direction of the belt member, and the first pressing member is configured to be movable between an operating position that suppresses the curvature of the widthwise end of the belt member and a non-operating position spaced apart from the widthwise end of the belt member, and a functional member is detachably disposed to the device body in the widthwise direction of the belt member in a state adjacent to the belt member of the transfer unit. In the photocopier, the functional member is configured to be immovable from the main body of the device by a second retaining member, the second retaining member is configured to be movable between an operating position that prevents the functional member from being removed and a non-operating position that allows it to be removed, the first retaining member and the second retaining member are configured to be movable between an operating position and a non-operating position by a common operating member, and the operating member is switchable between a first switching position that selects the non-operating position of the first retaining member and the operating position of the second retaining member, and a second switching position that selects the operating position of the first retaining member and the non-operating position of the second retaining member. [Effects of the Invention]

[0011] According to the present invention, the attachment and detachment of the unit can be expedited. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of the image forming apparatus. [Figure 2A] This is a perspective view of the transfer unit. [Figure 2B] This is a side view of a transfer apparatus with a PCDU mounted on a transfer unit. [Figure 3A] This is a perspective view of the transfer unit with the PCDU retainer in the upright position. [Figure 3B] This is a front view of the operating lever in the first switching position. [Figure 3C] This is a front view of the operating link of the PCDU retainer. [Figure 3D]Perspective view of the operating link of the PCDU retainer. [Figure 4A] Perspective view of the transfer unit with the PCDU retainer fallen down. [Figure 4B] Front view of the operation lever at the second switching position. [Figure 4C] Front view of the operating link of the PCDU retainer. [Figure 4D] Perspective view of the operating link of the PCDU retainer. [Figure 5A] Perspective view of the rotation axis of the operation lever and the operating link. [Figure 5B] Side view of the rotation axis of the operation lever and the operating link. [Figure 6A] Side view of the belt retainer in (a) the standing state and (b) the fallen state. <于 [Figure 6B] Perspective view of the operating link of the belt retainer. [Figure 7A] Side view of the state where the primary transfer roller abuts on the PCDU and the PCDU retainer stands up. [Figure 7B] Side view of the state where the primary transfer roller is separated from the PCDU and the PCDU retainer falls down. [Figure 8A] Perspective view of the operation lever. [Figure 8B] Front view of the operation lever. [Figure 9] ' Perspective view of the cam member. [Figure 10] Perspective view of the cam member and its peripheral structure seen from the back side. [Figure 11] Front view showing the structure around the first arm and the second arm. [Figure 12] Perspective view showing the second arm and its peripheral structure. [Figure 13] Perspective view of the second arm and its peripheral structure seen from the back side. [Figure 14] Front view showing the contact and separation structure of the detection sensor and the sensor bracket. [Figure 15] 'This is a perspective view of the first sensor bracket and the second sensor bracket as seen from the front side of the image forming apparatus. [Figure 16] This is a plan view showing the positioning of the second sensor bracket in the "separated" state. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations will be simplified or omitted as appropriate.

[0014] (●Image forming apparatus) Figure 1 shows the configuration of an image forming apparatus 1 according to one embodiment of the present invention. The image forming apparatus 1 shown in Figure 1 is a color printer with a tandem configuration in which multiple photoreceptors as latent image carriers are arranged side by side. Each photoreceptor can form a toner image of a color corresponding to color separation using toner as a developer supplied from a developing device. After superimposing and transferring the toner images formed on each photoreceptor onto an intermediate transfer surface, the superimposed image is transferred all at once to a sheet such as recording paper, thereby forming a multicolor image on the sheet. In the present invention, the image forming apparatus 1 is not limited to a color printer, but also includes color copiers, facsimile machines, and printing presses, among others.

[0015] In Figure 1, the image forming apparatus 1 has an image forming unit 1A positioned near the center in the vertical direction, a paper feeding unit 1B below it, and a document scanning unit 1C equipped with a document placement table 1C1 positioned above the image forming unit 1A. The image forming unit 1A has a transfer unit 20. An intermediate transfer belt 2, which acts as an intermediate transfer belt, is positioned on this transfer unit 20.

[0016] The intermediate transfer belt 2 has a horizontally stretched surface. Above the intermediate transfer belt 2, a configuration is provided for forming an image of a color that is complementary to the color separation color.

[0017] The image forming unit 1A is equipped with image forming units 10K, 10C, 10M, 10Y, and 10T, which are capable of forming images using complementary color toners (yellow, magenta, cyan, and black) and glossy images using transparent toner. Each image forming unit 10K, 10C, 10M, 10Y, and 10T has a photoreceptor 3K, 3C, 3M, 3Y, and 3T (transparent toner) capable of carrying an image, which is arranged side by side along the tensioned surface of the intermediate transfer belt 2. In the following description, if the content is common to all photoreceptors, the photoreceptor is indicated by the reference numeral 3.

[0018] Each photoreceptor 3K, 3C, 3M, 3Y, and 3T consists of a drum that can rotate in the same direction (counterclockwise in Figure 1), and around it are a charging device, a writing device 5, a developing device 6, a primary transfer roller 7 as a primary transfer member, and a cleaning device that perform image formation processing during the rotation process (for convenience, the reference numeral T is added to the symbols of each device, with photoreceptor 3T as the target).

[0019] The transfer unit 20 comprises an intermediate transfer belt 2, a plurality of primary transfer rollers 7 (for convenience, only the primary transfer roller 7T is shown with a reference numeral), and a plurality of rollers 2A to 2C, which serve as transfer members.

[0020] The intermediate transfer belt 2 sequentially transfers toner images from the imaging unit, which is equipped with each photoreceptor 3. The intermediate transfer belt 2 is wrapped around multiple rollers 2A to 2C, and multiple rollers not indicated in Figure 1, and can travel in a circular motion in the direction of the arrows in Figure 1. Rollers 2A and 2B tension the intermediate transfer belt 2 on both sides of the outer side in the direction of travel of the intermediate transfer belt 2 at opposing positions facing each photoreceptor 3 of the intermediate transfer belt 2. The secondary transfer opposing roller 2C faces the secondary transfer device 9 across the intermediate transfer belt 2.

[0021] The secondary transfer device 9 has a secondary transfer roller 9A. The secondary transfer roller 9A forms a secondary transfer nip between itself and the secondary transfer opposing roller 2C, with the intermediate transfer belt 2 in between. The secondary transfer opposing roller 2C is subjected to a secondary transfer bias of the same polarity as the toner, while the secondary transfer roller 9A is grounded. As a result, a secondary transfer field is formed in the secondary transfer nip that electrostatically moves the multicolor toner image on the intermediate transfer belt 2 from the belt side towards the secondary transfer roller 9A side. This secondary transfer nip transfers the multicolor toner image to the sheet that has been transported to the secondary transfer nip.

[0022] Recording sheets are fed from the paper feed unit 1B to the secondary transfer position. The paper feed unit 1B comprises multiple paper feed cassettes 1B1 and multiple transport rollers 1B2. The multiple transport rollers 1B2 are arranged in the transport path of the recording sheets fed from the paper feed cassettes 1B1.

[0023] The writing device 5 irradiates the photoreceptors 3K, 3C, 3M, 3Y, and 3T with writing light, forming an electrostatic latent image on the photoreceptors 3K, 3C, 3M, 3Y, and 3T corresponding to the image information. This image information is obtained by scanning the original document on the original document tray 1C1 of the original document scanning unit 1C, or from image information output from a computer.

[0024] The document scanning unit 1C is equipped with a scanner 1C2 and an automatic document feeder 1C3. The scanner 1C2 exposes and scans the document on the document tray 1C1. The automatic document feeder 1C3 is positioned on the upper surface of the document tray 1C1. The automatic document feeder 1C3 is configured to be able to flip the document as it is fed onto the document tray 1C1, allowing scanning of both the front and back sides of the document.

[0025] The electrostatic latent image formed on the photoreceptor 3 by the writing device 5 is processed into a visible image by the developing device 6 (indicated by the symbol 6T in Figure 1 for convenience) and primary transferred to the intermediate transfer belt 2. Once the toner images of each color are superimposed and transferred onto the intermediate transfer belt 2, they are collectively secondary transferred to the recording sheet by the secondary transfer device 9.

[0026] The second-transferred recording sheet has the unfixed image on its surface fixed by the fixing device 11. The fixing device 11 has a belt fixing structure that includes a fixing belt heated by a heating roller and a pressure roller that is in contact with the fixing belt. By providing a contact area between the fixing belt and the pressure roller, i.e., a nip area, the heating area on the recording sheet can be expanded compared to a hot roller fixing method.

[0027] The recording sheet that has passed through the fixing device 11 has its transport direction switched by a transport path switching claw located behind the fixing device 11. Specifically, the transport path switching claw selects the transport direction to either the transport path toward the paper discharge section 13 or the reverse transport path RP.

[0028] In the image forming apparatus 1 having the above configuration, an electrostatic latent image is formed on a uniformly charged photoreceptor 3 by exposure scanning of a document placed on the document placement table 1C1, or by image information from a computer. After the electrostatic latent image is processed into a visible image by the developing apparatus 6, the toner image is first transferred to the intermediate transfer belt 2.

[0029] The toner image transferred to the intermediate transfer belt 2 is transferred directly to the recording sheet fed from the paper feed unit 1B in the case of a single-color image, and in the case of a multi-color image, the primary transfer is repeated to superimpose the images before being transferred all at once to the recording sheet in a secondary transfer. After the secondary transfer, the recording sheet has the unfixed image fixed by the fuser unit 11 and is then fed to the paper discharge unit 13 or inverted and fed again towards the secondary transfer position.

[0030] In Figure 1, the intermediate transfer belt 2 is constructed by forming one or more layers of PVDF (vinyldenine fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC (polycarbonate), etc., and dispersing conductive materials such as carbon black. The volume resistivity of the intermediate transfer belt 2 is set to 10 8 ~10 12 Ωcm, and surface resistivity of 10 9 ~10 13It is adjusted to be within the range of Ωcm.

[0031] Furthermore, a release layer may be coated onto the surface of the intermediate transfer belt 2 as needed. Suitable materials for the coating include, but are not limited to, fluororesins such as ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluoroethylene), PVDF (vinyldenine fluoride), PEA (perfluoroalkoxy fluororesin), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and PVF (vinyl fluoride).

[0032] The intermediate transfer belt 2 can be manufactured by casting, centrifugal molding, or other methods, and its surface may be polished as needed. If the volume resistivity of the intermediate transfer belt 2 exceeds the range described above, the bias required for transfer will increase, which is undesirable as it leads to increased power supply costs.

[0033] Furthermore, the charge potential of the intermediate transfer belt 2 increases during the transfer process and the transfer paper peeling process, and self-discharge becomes difficult, making it necessary to provide a means for static discharge. Also, if the volume resistivity and surface resistivity fall below the above range, the charge potential decays more quickly, which is advantageous for static discharge, but the current during transfer flows in the planar direction, causing toner to splatter.

[0034] Therefore, it is preferable that the volume resistivity and surface resistivity of the intermediate transfer belt 2 in this embodiment be within the above range. The volume resistivity and surface resistivity were measured by connecting an HRS probe (inner electrode diameter 5.9 mm, ring electrode inner diameter 11 mm) to a high-resistivity resistivity meter (Mitsubishi Chemical Corporation: High Resista IP), applying a voltage of 100 V (500 V for surface resistivity) to both sides of the intermediate transfer belt 2, and using the measured values ​​after 10 seconds.

[0035] The intermediate transfer belt 2 is wrapped around at least one pair of rollers, rollers 2A and 2B, and a secondary transfer opposing roller 2C located at the secondary transfer position. The drive roller 2A is set to rotate clockwise, allowing the intermediate transfer belt 2 to move in the direction of the arrow shown inside the intermediate transfer belt 2 in Figure 1. The transfer surface of the belt moving between rollers 2A and 2B faces the photoreceptors 3K, 3Y, 3C, 3M, and 3T of each imaging unit.

[0036] A primary transfer roller 7 (indicated by reference numeral 7T in Figure 1, for special toner) is positioned opposite each photoreceptor, with the intermediate transfer belt 2 in between. This roller corresponds to a transfer member for electrostatically transferring the visible image on the photoreceptor. The primary transfer roller 7 used in this embodiment is made by coating a metal (iron, SUS, AI, etc.) core with a foaming resin.

[0037] The thickness of the foamed resin is 2 mm to 10 mm. In addition, known blade-shaped or brush-shaped materials can also be used as transfer components.

[0038] In this embodiment, in addition to the toner used for full-color image formation, white toner is used to form a white background on the image. Alternatively, transparent toner may be used to improve the gloss and transferability of the image, and light cyan toner, light magenta toner, etc., may be selected to increase the color gamut. In some cases, metallic toners such as gold toner or silver toner may be used as a background to create colored metallic colors such as reddish-bronze or bronze.

[0039] (●Transfer unit and transfer device) Figure 2A is a perspective view of the transfer unit 20 described above. Belt retainers 1-1, 1-2, 1-3, and 1-4, which serve as first retaining members, are arranged at two locations on the front left and right sides and two locations on the rear left and right sides of the transfer unit 20. These belt retainers 1-1 to 1-4 make it possible to suppress upward curvature at both ends in the width direction of the intermediate transfer belt 2.

[0040] Furthermore, PCDU retainers 4-1 and 4-2 are provided as second retaining members at two locations on the front left and right sides of the transfer unit 20. These PCDU retainers 4-1 and 4-2 prevent the two PCDUs 2-1 to 2-2 on the right side (downstream side) of Figure 2B from detaching towards the front side of Figure 2B. Similar PCDU retainers may also be provided on the front side of the three PCDUs 2-3 to 2-5 on the left side (upstream side) of Figure 2B.

[0041] An operating lever 16 is provided at the front right end of the transfer unit 20. By rotating this operating lever 16, the belt retainers 1-1 to 1-4 and the PCDU retainers 4-1 and 4-2 can be moved between the operating and non-operating positions. By providing the operating lever 16, belt retainers 1-1 to 1-4, and PCDU retainers 4-1 and 4-2 on the transfer unit 20, the link mechanism described later can be easily and inexpensively constructed.

[0042] Figure 2B shows the transfer apparatus of this embodiment. In this transfer apparatus, five PCDU2-1 to 2-5 are arranged on the transfer unit 20. The five PCDU2-1 to 2-5 correspond to the imaging units 10T, 10C, 10M, 10Y, and 10K in Figure 1.

[0043] PCDU2-1 to 2-5 are arranged in order from the downstream side to the upstream side in the direction of travel of the intermediate transfer belt 2. PCDU2-1 corresponds to the image unit 10T (transparent toner), PCDU2-2 to the image unit 10C (cyan), PCDU2-3 to the image unit 10M (magenta), PCDU2-4 to the image unit 10Y (yellow), and PCDU2-5 to the image unit 10K (black).

[0044] (●Second link mechanism of the PCDU retainer) Figures 3A to 3D and 4A to 4D show the second linkage mechanism between the operating lever 16 and the PCDU retainers 4-1 and 4-2. The movement of the operating lever 16 is transmitted to the PCDU retainers 4-1 and 4-2 via this second linkage mechanism.

[0045] Figures 3A to 3D show the state when the PCDU retainers 4-1 and 4-2 are moved to the operating position at the first switching position of the operating lever 16. In this operating position, the PCDU retainers 4-1 and 4-2 stand upright, preventing the PCDU 2-1 to 2-2 from detaching towards the front as shown in Figure 2B.

[0046] Figures 4A to 4D show the state when the PCDU retainers 4-1 and 4-2 are moved to the non-operational position at the second switching position of the operating lever 16. In this non-operational position, the PCDU retainers 4-1 and 4-2 collapse, allowing the PCDUs 2-1 to 2-2 to detach towards the front as shown in Figure 2B.

[0047] The operating lever 16 is attached to the rotating shaft 14 in Figure 3C. The first link 9 is fixed to the rotating shaft 14. The first link 9 is biased by a tension spring 50 in a clockwise direction, i.e., from the second switching position to the first switching position.

[0048] In the first switching position shown in Figure 3C, the tension spring 50 is at its shortest length, and the rotation axis 14 is located on the longitudinal extension of the tension spring 50. In this state, the biasing force of the tension spring 50 becomes zero. The rotation axis 14 or the operating lever 16 cannot rotate further to the right than shown in Figures 3C and 3D due to the stopper.

[0049] As shown in Figures 5A and 5B, the first link 9 is connected to the fourth link 6 via the second link 12 and the third link 11. That is, one end of the second link 12 and the third link 11 are connected to pin 9a of the first link 9.

[0050] Furthermore, the other ends of the second link 12 and the third link 11 are connected to the right end of the fourth link 6. That is, the pin 12a at the other end of the second link 12 is engaged with the elongated hole 15 formed near the right end of the fourth link 6. Also, the pin 11a at the other end of the third link 11 is connected to the right end of the fourth link 6.

[0051] As shown in Figures 3A and 4A, the fourth link 6 is positioned horizontally between the PCDU pressers 4-1 and 4-2 on the front side of the transfer unit 20. The fourth link 6 slides in the longitudinal direction from left to right, causing the PCDU pressers 4-1 and 4-2 to stand up and fall down.

[0052] By rotating the rotation axis 14 from side to side, the fourth link 6 of the second link mechanism slides from side to side. This sliding movement causes the PCDU retainers 4-1 and 4-2 to be raised as shown in Figures 3A to 3D, or to be lowered as shown in Figures 4A to 4D.

[0053] Elongated holes 4-1-1 and 4-2-1 are formed in the longitudinal middle of the PCDU retainers 4-1 and 4-2, and fixing pins 8-1 and 8-2 are slidably engaged with these elongated holes. One longitudinal end of the PCDU retainers 4-1 and 4-2 is connected to the fourth link 6 by pins 4-1-2 and 4-2-2.

[0054] Therefore, by sliding the fourth link 6 from side to side, the PCDU retainers 4-1 and 4-2 can be raised and lowered as described above. Retaining pins 4-1-3 are attached to the tips of pins 4-1-2 and 4-2-2, as shown in Figure 5A, to prevent the PCDU retainers 4-1 and 4-2 from coming loose.

[0055] The left end of the fourth link 6 is connected to the connecting shaft 8 via the fifth link 7. The connecting shaft 8 is supported by the machine frame and connects the front cam 7-1 and the rear cam 7-2, as shown in Figures 3A and 4A. Cams 7-1 and 7-2 allow the belt retainers 1-1 to 1-4 to move up and down.

[0056] (●First link mechanism of the belt retainer) The operating lever 16, which serves as the operating member, is connected to the four belt retainers 1-1, 1-2, 1-3, and 1-4 via the first link mechanism shown in Figures 6A and 6B. Figures 6A and 6B show the connecting structure that links the rear cam 7-2 to the rear belt retainers 1-3 and 1-4. The front cam 7-1 and the front belt retainers 1-1 and 1-2 are connected by a similar connecting structure.

[0057] At the first switching position of the operating lever 16 as shown in Figures 3A to 3D, belt retainers 1-1 to 1-4 move to the non-operating position (away from the intermediate transfer belt 2). At the second switching position of the operating lever 16 as shown in Figures 4A to 4D, belt retainers 1-1 to 1-4 move to the operating position (pressing the widthwise end of the intermediate transfer belt 2).

[0058] The cam follower 5-2-2 is engaged with the cam 7-2 at the right end of Figure 6A. The cam follower 5-2-2 has an F-shape in side view and is integrated with the slider 5-2. The slider 5-2 is biased to the right in Figure 6A by a tension spring 5-2-3.

[0059] Pins 5-2-1 are fixed to both ends of slider 5-2. These pins 5-2-1 engage with the belt retainer rotating parts (cam grooves) 1-3-3 and 1-4-3 of belt retainers 1-3 and 1-4.

[0060] Belt retainers 1-3 and 1-4 are supported so as to be rotatable in the left-right direction in Figure 6A. As pin 5-2-1 slides together with slider 5-2 in the left-right direction, belt retainers 1-3 and 1-4 rise (stand up) as shown in Figure 6A(a) or fall down (tumble down) as shown in Figure 6A(b).

[0061] To suppress the upward curvature of both ends of the intermediate transfer belt 2 in the width direction, the slider 5-2 is moved to the left by the cam 7-2 as shown in Figure 6A(b) to lower (fold down) the belt retainers 1-3 and 1-4. In this state, the belt retainers 1-3 and 1-4 press against the ends of the intermediate transfer belt 2 in the width direction by their own weight.

[0062] Therefore, the force acting on cam 7-2 is small, and the operating force required to rotate the operating lever 16 from the first switching position to the second switching position and from the second switching position to the first switching position is very small. As a result, cam 7-2 and belt retainer rotating parts 1-3-3 and 1-4-3 can be constructed at low cost using resin molded parts. In addition, the durability of these components, such as cam 7-2, can be improved.

[0063] Each belt retainer 1-3 and 1-4 has a two-layer structure consisting of an upper hard plate-like portion and a lower soft felt portion. Specifically, as illustrated in Figure 6B, one of the belt retainers 1-3 has a two-layer structure consisting of an upper hard plate-like portion 1-3-1 and a lower soft felt portion 1-3-2. The soft felt portion 1-3-2 is intended to prevent damage to the intermediate transfer belt 2, and in the lowered state shown in Figures 6A(b) and 6B, the soft felt portion 1-3-2 contacts the widthwise end of the intermediate transfer belt 2.

[0064] (●Transfer unit attachment / detachment mechanism)

[0065] Next, referring to Figures 7A and 7B, the connection / separation mechanism (third link mechanism) that moves the driven roller 33A at the left end of the transfer unit 20 toward and toward (raises and lowers) the PCDU2-1 at the downstream end will be explained. The first transfer roller 19-1, the driven roller 21A, and the second transfer roller 19-2 at the right end are moved toward and toward (raises and lowers) the PCDU2-1 and PCDU2-2 by other connection / separation mechanisms.

[0066] Figures 7A and 7B are cross-sectional views of the image forming apparatus 1, seen from the rear side, opposite to that shown in Figures 1 to 4C. The rotating shaft 14, connected to the aforementioned operating lever 16, protrudes from the rear side of the apparatus. A cam 14-1 is attached to this rotating shaft 14.

[0067] A front slider 17 is positioned so as not to interfere with the rotation axis 14. This front slider 17 is positioned to be movable in the left-right direction in Figures 7A and 7B.

[0068] A cam follower 23 is formed on the front slider 17, which the cam 14-1 can contact. When the operating lever 16 is rotated against the tension spring 50 as shown in Figure 4B, the cam 14-1 contacts the cam follower 23 as shown in Figure 7B, moving the front slider 17 to the right.

[0069] On the other hand, a driven roller 33A, which is one of the rollers that tensions the intermediate transfer belt 2, is provided at one end of the rotating member 33. The rotating member 33 is provided so as to be rotatable about a pivot point 33a. The rotating member 33 has a hole 33b at the end opposite to the side on which the driven roller 33A is provided.

[0070] An insertion portion 17a, provided on the front slider 17, is inserted into the hole 33b. The insertion portion 17a is constructed by press-fitting a ball bearing onto a shaft fixed to the front slider 17. By providing a ball bearing in the insertion portion 17a, the sliding resistance between the insertion portion 17a and the rotating member 33 can be reduced.

[0071] As shown in Figure 7B, when the front slider 17 moves to the right, the rotating member 33 rotates counterclockwise around the pivot point 33a, separating the driven roller 33A from the PCDU2-1 at the downstream end. In this state, the cam 14-1 is in contact with the cam follower 23, and the frictional force between them is greater than that of the tension spring 50. Therefore, even if you release your hand from the operating lever 16 in the state shown in Figure 4B, the operating lever 16 will remain stopped in the state shown in Figure 4B.

[0072] Therefore, with a single release operation of the operating lever 16 from the first switching position to the second switching position, 1) The driven roller 33A can be held in a separated state from PCDU2-1. 2) The PCDU retainers 4-1 and 4-2 can be held in a collapsed state. 3) By lowering (tilting) the belt retainers 1-1 to 1-4, the intermediate transfer belt 2 can be held in a state where the upward curvature at both ends in the width direction is suppressed. Therefore, the attachment and detachment of PCDU2-1 to 2-2 in the front-to-back direction in Figure 2B can be performed easily and quickly without damaging the intermediate transfer belt 2.

[0073] As mentioned above, the operating lever 16 is biased clockwise by the tension spring 50, i.e., from the second switching position to the first switching position. If the operating lever 16 is not biased clockwise by the tension spring 50, there is a possibility that the operating lever 16 will stop at an intermediate position between the first and second switching positions.

[0074] In that case, the user may mistakenly believe that the operating lever 16 has been fully switched to the second switching position, and that the belt retainers 1-1 to 1-4 are in the operating state (belt retainer state). Then, they may continue the attachment and detachment work of PCDU 2-1 to 2-2 and inadvertently damage the intermediate transfer belt 2.

[0075] By providing a tension spring 50 on the operating lever 16, it is possible to prevent the operating lever 16 from unexpectedly stopping at an intermediate position between the first and second switching positions. Therefore, it is possible to prevent erroneous operation of attaching or detaching the PCDU based on the user's misjudgment of the position of the operating lever 16.

[0076] Furthermore, if the operating lever 16 is moved even slightly clockwise from the second switching position after the PCDU 2-1 to 2-2 is installed, the cam 14-1 detaches from the cam follower 23. Immediately, the operating lever 16 returns to the first switching position due to the biasing force of the tension spring 50. Consequently, the PCDU retainers 4-1 and 4-2 instantly return to the upright position, and the belt retainers 1-1 to 1-4 also instantly rise (stand up). In this way, the PCDU installation and detachment process can be completed quickly and reliably.

[0077] In the first switching position shown in Figure 3C, the tension spring 50 is at its shortest length, and the rotation axis 14 is located on the longitudinal extension of the tension spring 50. In this state, the biasing force of the tension spring 50 becomes zero. The rotation axis 14 or the operating lever 16 cannot rotate further to the right than shown in Figures 3C and 3D due to the stopper.

[0078] (●Other contact / separation mechanisms) The other contact / separation mechanism that brings the first transfer roller 19-1, the driven roller 21A, and the second transfer roller 19-2 at the right end into contact with and separates from PCDU2-1 and PCDU2-2 has a cam member 31 to which the driving force of the motor is transmitted. As shown in Figure 9, the cam member 31 has a first cam 31A and a second cam 31B and is rotatably mounted around the rotation axis 31a.

[0079] The second cam 31B is a ball bearing with an outer ring and is an eccentric cam with respect to the rotating shaft 31a. The first cam 31A abuts against the front slider 17, which acts as a sliding member.

[0080] The front slider 17 is biased to the left by the spring 18. The motor's driving force causes the first cam 31A to rotate, changing the surface that contacts the front slider 17, thereby moving the front slider 17 to the right in Figures 7A and 7B, against the biasing force of the spring 18.

[0081] A primary transfer roller 19-1 (corresponding to the primary transfer roller 7T in Figure 1) is provided at one end of the rotating member 34. The rotating member 34 is rotatable about a pivot point 34a. The rotating member 34 has a hole 34b at the end opposite to the side on which the primary transfer roller 19-1 is provided.

[0082] A pin 17b provided on the front slider 17 is inserted into the hole 34b. The spring 35 is fixed to the housing of the image forming apparatus 1 and biases the rotating member 34 to rotate clockwise around the pivot point 34a as shown in Figures 7A and 7B.

[0083] The driven roller 33A is a first tension roller located downstream of the primary transfer roller 19-1 in the downstream primary transfer section. As the front slider 17 moves in the left-right direction as shown in Figures 7A and 7B, the insertion section 17a pushes the rotating member 33, causing the rotating member 33 to rotate around the pivot point 33a.

[0084] As a result, the driven roller 33A changes its position. Also, as the front slider 17 moves to the right in Figures 7A and 7B, the rotating member 34 is pushed by the pin 17b and rotates counterclockwise around the pivot point 34a against the biasing force of the spring 35.

[0085] Alternatively, as the front slider 17 moves to the left in the figure, the biasing force of the spring 35 causes the rotating member 34 to rotate clockwise around the pivot point 34a. As a result, the primary transfer roller 19-1 provided on the rotating member 34 moves toward and away from the photoreceptor 3.

[0086] Furthermore, as shown in Figures 7A and 7B, upstream of the primary transfer roller 19-1 in the direction of travel of the intermediate transfer belt 2, and downstream of the primary transfer roller 7C which is one position upstream of the primary transfer roller 19-1, a driven roller 21A is provided that is stretched over the intermediate transfer belt 2 and is driven by the rotation of the intermediate transfer belt 2. The driven roller 21A is provided at one end of the rotating member 21.

[0087] The rotating member 21 is mounted so as to be rotatable around the pivot point 21a. The rotating member 21 is subjected to a force by the spring 39 that causes it to rotate clockwise around the pivot point 21a.

[0088] For example, as shown in Figure 7A ⇒ Figure 7B, when the front slider 17 moves to the right in Figure 7A, the rotating member 34 rotates counterclockwise around the pivot point 34a against the biasing force of the spring 35, and the primary transfer roller 19-1 moves in a direction away from the photoreceptor 3.

[0089] Furthermore, as the front slider 17 moves to the right in Figure 7A, the pin 17c (see Figure 12) provided on the front slider 17 presses against the side of the rotating member 21 opposite to the side where the driven roller 21A is provided.

[0090] As a result, the rotating member 21 rotates counterclockwise around the pivot point 21a against the biasing force of the spring 39. Consequently, in Figure 7B, the driven roller 21A separates from the intermediate transfer belt 2.

[0091] In this way, by changing the arrangement of the driven rollers 33A in the "contact" and "separated" states, the position on which the intermediate transfer belt 2 is tensioned in each state can be changed. Therefore, the intermediate transfer belt 2 can be tensioned in the appropriate position, and the detection sensor 22 can accurately detect the running speed of the intermediate transfer belt 2.

[0092] The detection sensor 22 optically detects the scale marks on the scale tape attached to the inner surface of the end of the intermediate transfer belt 2, and is sometimes called a "scale mark sensor" or simply a "scale sensor". The detection sensor 22 is a reflective sensor, with the light-emitting side positioned below the end of the intermediate transfer belt 2 and the scale tape, which is the reflective side, positioned above it. If the intermediate transfer belt 2 is wavy, the detection sensor 22 will not be able to read it properly, so a pressing part 22a that presses down on the intermediate transfer belt 2 from above is provided integrally with the detection sensor 22, as shown in Figure 3D.

[0093] The pressing portion 22a presses down on the end of the intermediate transfer belt 2 from above, thereby maintaining a constant distance between the detection sensor 22 and the belt and ensuring detection accuracy. Therefore, the pressing portion 22a of the detection sensor 22 incidentally provides a belt-holding function.

[0094] In particular, in this embodiment, by changing the tensioning position of the driven roller 33A, which is positioned downstream of the primary transfer roller 19-1 of the downstream primary transfer section and tensions the intermediate transfer belt 2, the tensioning posture of the intermediate transfer belt 2 can be appropriately changed, and the detection sensor 22 can accurately detect the running speed of the intermediate transfer belt 2. By shifting the position where the intermediate transfer belt 2 is tensioned downward as shown in Figure 7B, damage to the photoreceptor 3T (see Figure 1) and the intermediate transfer belt 2 due to interference between the photoreceptor 3T and the intermediate transfer belt 2 can be prevented when attaching or detaching the PCDU or transfer unit 20.

[0095] (● Mechanism for contacting and separating the detection sensor) Next, the mechanism for raising and lowering the detection sensor 22 will be described. As shown in Figure 7A, the first arm 37 grips the outer circumferential surface of the second cam 31B provided on the cam member 31. The first arm 37 is rotatably mounted around the pivot point 37a.

[0096] The pivot point 37a is fixed to the front slider 17 via a ball bearing. As the second cam 31B rotates, the first arm 37 rotates around the pivot point 37a, as shown in Figure 7A. In addition, as the front slider 17 moves due to the rotation of the first cam 31A (see Figure 12) provided on the cam member 31, the first arm 37 moves in the left-right direction as shown in Figure 7A.

[0097] Figure 9 is a perspective view showing the cam member 31. As shown in Figure 9, the cam member 31 has a first cam 31A and a second cam 31B. The cam member 31 is rotatably mounted around the rotation axis 31a.

[0098] The first cam 31A has small diameter, medium diameter, and large diameter sections with different diameters, each spanning 120 degrees. As shown in Figure 10, the first cam 31A contacts the cam follower 36, which is made of a ball bearing.

[0099] The cam follower 36 is a first transmission member provided on the first arm 37. By rotating the first cam 31A, the surface that contacts the cam follower 36 is changed, allowing the front slider 17 to move in the left-right direction in Figure 7A. Furthermore, as the front slider 17 moves, the first arm 37, whose pivot point 37a is fixed to the front slider 17, moves in conjunction with the front slider 17 in the left-right direction in Figure 7A.

[0100] As shown in Figures 10 and 11, the first arm 37 grips the second cam 31B at two points, gripping portions 37c1 and 37c2. The rotation of the second cam 31B causes the first arm 37 to rotate around the pivot point 37a.

[0101] As shown in Figure 10, a thrust stopper member 60, which serves as both a restricting member and a retaining member, is attached to the first arm 37. The thrust stopper member 60 has a contact portion 60a and a restricting portion 60b, which serve as retaining portions.

[0102] By bringing the contact portion 60a into contact with the pivot point 37a of the first arm 37 from above as shown in Figure 10, it functions as a retainer against the front slider 17 of the pivot point 37a. Figure 11 shows the thrust retaining member 60 removed.

[0103] Furthermore, the thrust deterrent member 60 also contacts the pivot point 37a from below in Figure 10, preventing it from coming loose downwards in Figure 10. The restricting portion 60b of the thrust deterrent member 60 is a surface provided along the outer circumferential surface of the outer ring of the second cam 31B, which is a bearing.

[0104] The restricting portion 60b restricts the position of the outer circumferential surface of the second cam 31B, thereby restricting the relative movement direction of the first arm 37 with respect to the second cam 31B. In other words, it restricts the first arm 37 from moving in a direction other than along the outer circumferential surface of the second cam 31B, for example, in the sliding direction relative to the second cam 31B. Consequently, positional deviations such as tilting of the first arm 37 with respect to the second cam 31B can be prevented, and wear of the gripping portions 37c1 and 37c2 can be prevented.

[0105] In this embodiment, the number of parts in the transfer device can be reduced by providing a contact portion 60a that functions as a retaining mechanism for the first arm 37 against the front slider 17, and a restricting portion 60b that restricts the relative movement direction of the first arm 37 with respect to the second cam 31B, on a common thrust stopper member 60. However, these may be provided on separate members.

[0106] Figure 12 is a front perspective view of the area around the first arm 37 and the second arm 38. Figure 13 is a rear perspective view of the first arm 37 and the second arm 38.

[0107] As shown in Figure 12, the second arm 38, which serves as the second link member, has other elongated holes 38a and 38b at both ends. One end 37b of the first arm 37 is inserted into the other elongated hole 38a.

[0108] As shown in Figure 13, one end 37b of the first arm 37 has a bearing 40. The bearing 40 is provided so as to be movable relative to the other elongated hole 38a. The bearing 40 is the other insertion part into the other elongated hole 38a.

[0109] The bearing 40 is provided with a parallel pin 40a on its back side as a retaining part. The length of the parallel pin 40a is shorter than the length of the other elongated holes 38a in the longitudinal direction.

[0110] By positioning the parallel pin 40a approximately parallel to the longitudinal direction of the other elongated holes 38a, the bearing 40 can be inserted into the other elongated holes 38a. In the state shown in Figure 13, the parallel pin 40a functions as a retainer for the bearing 40 to remain in place of the other elongated holes 38a.

[0111] As shown in Figure 12, a bearing 41 is inserted into the elongated hole 38b. The bearing 41 is fixed to the first sensor bracket 43, which serves as a retaining member, by a stepped screw 42.

[0112] The bearing 41 is movably mounted within the elongated hole 38b. The bearing 41 is the insertion part for the elongated hole 38b.

[0113] The rotation of the cam member 31 moves the front slider 17 to the right from the state shown in Figure 7A. As a result, the rotation of the second cam 31B causes the first arm 37 to rotate counterclockwise around the pivot point 37a. Consequently, the tip of the first arm 37 moves upward from Figure 7A to Figure 7B.

[0114] As a result, the second arm 38 moves upward and to the right as shown in Figure 7B. This causes the bearing 41 to move relative to one end of the elongated hole 38b and come into contact with the wall surface forming the elongated hole 38b. Then, the second arm 38 pulls the first sensor bracket 43 downward and to the left as shown in Figure 7B.

[0115] Figure 14 shows the configuration of the first sensor bracket 43 and the area around the detection sensor 22, and is a diagram showing the state with the rotating member 21 removed from Figure 7A, etc. For convenience, the detection sensor 22 and the second sensor bracket 44 are shown in a simplified manner in Figure 14.

[0116] As shown in Figure 14, the first sensor bracket 43 is rotatably mounted around a pivot point 43a. The first sensor bracket 43 is subjected to a force by a spring 45 fixed to the housing of the image forming apparatus 1, which causes it to rotate counterclockwise around the pivot point 43a as shown in Figure 14.

[0117] Furthermore, a regulating member 63 is fixed to the first sensor bracket 43. The pin 17d of the front slider 17 is inserted into the hole 63a of the regulating member 63. In the "contact" state in Figure 7A and the "separated" state in Figure 7B, the pin 17d contacts the left side of the wall surface forming the hole 63a, thereby applying a force to the first sensor bracket 43 that causes the front slider 17 to rotate clockwise around the pivot point 43a as shown in Figure 14.

[0118] The second sensor bracket 44 is fixed to the first sensor bracket 43 via a stud 43b provided on the first sensor bracket 43. The second sensor bracket 44 holds the detection sensor 22. As shown in Figure 14, the second sensor bracket 44 has a hook 44a to which one end of a spring 62 (see Figures 7A and 7B) is attached, a first contact portion 44b, and a second contact portion 44c.

[0119] In the "contact" state shown in Figure 7A, the second sensor bracket 44 is biased by the spring 62 and moves in a direction that rotates clockwise around the pivot point 43a, and is positioned so that the first contact portion 44b contacts the stud 64 provided on the housing of the image forming apparatus 1.

[0120] On the other hand, in the "separated" state shown in Figure 7B, the pin 17d provided on the front slider 17 moves to the right compared to Figure 7A, causing the first sensor bracket 43, the second sensor bracket 44, and the detection sensor 22 to rotate counterclockwise around the pivot point 43a due to their own weight and the biasing force of the spring 45. Also, the pin 43c provided on the first sensor bracket 43 shown in Figure 15 presses against the bent portion 44d of the second sensor bracket 44, causing the second sensor bracket 44 to rotate counterclockwise around the pivot point 43a as shown in Figure 7B.

[0121] As a result, the first sensor bracket 43, the second sensor bracket 44, and the detection sensor 22 rotate counterclockwise in Figure 7B, moving downward in Figure 7B, which is further away from the photoreceptor 3 than in Figure 7A. Figure 15 is a perspective view showing the back side of the first sensor bracket 43 and the second sensor bracket 44 in Figure 7B.

[0122] Furthermore, in the "separated" state shown in Figure 7B, as the pin 17d moves further to the right, the force with which the pin 17d presses the regulating member 63 to the left in Figure 14 is released, as shown in Figure 14. Simultaneously, as described above, the second arm 38 pulls the first sensor bracket 43 towards the lower left of Figure 14, causing the first sensor bracket 43 to rotate clockwise around the pivot point 43a in Figure 14. As a result, the second sensor bracket 44, which is fixed to the first sensor bracket 43 via the stud 43b, moves upward in Figure 14, and the detection sensor 22 also moves upward in Figure 14.

[0123] In this case, as shown in Figure 16, the second sensor bracket 44 is positioned so that its second contact portion 44c contacts the positioning portion 21b of the rotating member 21. In other words, upward movement of the second sensor bracket 44 and the detection sensor 22 as shown in Figure 14 is restricted, and the detection sensor 22 is positioned.

[0124] In this way, by transmitting the driving force of the cam member 31 to the first sensor bracket 43 via link members such as the first arm 37 and the second arm 38, and by creating a mechanism that rotates the first sensor bracket 43, the first sensor bracket 43 can be rotated in a desired direction.

[0125] The number of link members connected to the first sensor bracket 43 that holds the detection sensor 22 is not limited to two in this embodiment. There may be three or more, or there may be just one.

[0126] Furthermore, the combination of the member providing the elongated hole and the member providing the insertion member such as a pin inserted into it may be reversed. Also, it is not necessarily required that the motor's driving force activate all of the detection sensor 22, primary transfer roller 19-1, driven rollers 21A and 33A.

[0127] As described above, in this embodiment, the rotation of the first cam 31A shown in Figure 9 moves the front slider 17 in the left-right direction in Figure 7A, thereby moving each primary transfer roller 7 and the driven roller. Furthermore, the rotation of the first cam 31A and the second cam 31B moves the detection sensor 22.

[0128] Specifically, in the "contact" state shown in Figure 7A and the "separated" state shown in Figure 7B, the position of the detection sensor 22 can be changed by applying a force in a clockwise direction to the first sensor bracket 43 through the pressure exerted by the pin 17d (see Figure 14), which moves due to the rotation of the first cam 31A. In the "separated" state, the position of the detection sensor 22 can be changed by the rotation of the second cam 31B, which pulls the first sensor bracket 43 into the second arm 38.

[0129] (●Operating lever) The operating lever 16 has a disc-shaped body portion 16b, as shown in Figures 8A and 8B. The center of the disc-shaped body portion 16b is connected to the rotation shaft 14. A knob portion 16a is formed on the front side of the body portion 16b so as to coincide with the extension of the rotation shaft 14.

[0130] The knob portion 16a extends linearly from near the center of the main body portion 16b to the radial outer circumference. By applying forces F in opposite directions to both ends of the knob portion 16a, straddling the extension of the rotation axis 14, the force F is distributed, allowing the knob portion 16a to rotate easily.

[0131] The main body portion 16b is formed to be lower than the height of the knob portion 16a. A stepped portion 16c is formed on the outer circumference of the main body portion 16b, and the entire perimeter of this stepped portion 16c is covered by the front cover 20-1 of the transfer unit 20. As a result, the internal mechanism inside the front cover 20-1 is completely invisible from the front or from a diagonal direction.

[0132] Furthermore, a notch 20-2 is formed in the front cover 20-1. The operating lever 16 is exposed to the left of this notch 20-2. The notch 20-2 is an obtuse V-shape, so that when the knob 16a is rotated to the first switching position (solid line) and the second switching position (dash line) in Figure 8B, the fingers holding the knob 16a do not interfere with the notch 20-2 of the front cover 20-1.

[0133] In other words, at the first and second switching positions, two sides of the V-shape of the notch 20-2 are approximately parallel to the knob 16a. This prevents fingers from getting caught in the notch 20-2 when rotating the knob 16a.

[0134] The operating force required for the operating lever 16 is lighter than that of the operating lever (manual lever 549 in Figure 14) of the transfer device described in Patent Document 1. In the transfer device described in Patent Document 1, the raising and lowering of multiple transfer rollers and multiple belt retaining members are performed by a single operating lever. Therefore, a large force is required to operate the operating lever. In addition, measures such as using a strong metal for the material of the cams and other components used in the contact and separation mechanism are necessary.

[0135] In contrast, in this embodiment, the driven roller 33A that tensions the downstream end of the intermediate transfer belt 2 is raised and lowered by the operating lever 16, while the other rollers (first transfer roller 19-1, driven roller 21A, and the second transfer roller 19-2 at the right end) are raised and lowered by a motor-driven cam member 31. As a result, the operating lever can be operated with light force, and costs can be reduced by using materials other than metal, such as resin, for the cams and other components used in the contact and release mechanism.

[0136] While embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. The sheet material includes paper (plain paper), cardboard, postcards, envelopes, thin paper, coated paper (such as coated paper and art paper), tracing paper, OHP sheets, plastic films, prepregs, copper foil, and the like. Furthermore, the functional material on the transfer unit is not limited to PCDU, and various functional materials that can be applied to the sheet material can be used.

[0137] <Note> Preferred embodiments of the present invention are described below. <First aspect> A transfer unit having a belt member for transporting a sheet member and a first pressing member for suppressing the curvature of the widthwise end of the belt member, wherein the transfer unit is detachably disposed to the device body in the widthwise direction of the belt member, the first pressing member being configured to move between an operating position that suppresses the curvature of the widthwise end of the belt member and a non-operating position spaced apart from the widthwise end of the belt member, and a functional member being detachably disposed to the device body in the widthwise direction of the belt member in a state adjacent to the belt member of the transfer unit, wherein the functional member A transfer device characterized in that a functional member is configured to be immovable from the main body of the device by a second pressing member, the second pressing member is configured to be movable between an operating position that makes the functional member immovable and a non-operating position that makes it detachable, the first pressing member and the second pressing member are configured to be movable between an operating position and a non-operating position by a common operating member, and the operating member is switchable between a first switching position that selects the non-operating position of the first pressing member and the operating position of the second pressing member, and a second switching position that selects the operating position of the first pressing member and the non-operating position of the second pressing member. <Second aspect> A transfer apparatus according to the first embodiment, characterized in that the second pressing member is disposed on the transfer unit. <Third aspect> A transfer apparatus according to the first or second embodiment, characterized in that the operating member is disposed in the transfer unit. <Fourth aspect> A transfer apparatus according to any one of the first to third embodiments, characterized in that it has a transfer unit and a transfer mechanism for bringing the transfer unit and the functional member into and out of contact, and the transfer mechanism is configured to be operated by the operating member. <Fifth aspect> A transfer apparatus according to any one of the first to fourth embodiments, characterized in that the operating member is biased from the second switching position to the first switching position by a biasing member, and is held in the second switching position against the biasing force of the biasing member at the second switching position. <Sixth aspect> The frictional force between the cam connected to the rotating shaft of the operating member and the cam follower in contact with the cam, The aforementioned A transfer apparatus according to any one of the first to fifth embodiments, characterized in that the operating member is held in the second switching position. <Seventh aspect> A transfer apparatus according to any one of the first to sixth embodiments, characterized in that the operating member is connected to the first pressing member via a first link mechanism and to the second pressing member via a second link mechanism. <Eighth aspect> A transfer apparatus according to any one of the first to seventh embodiments, characterized in that the operating member is connected to the connecting / separating mechanism via a third link mechanism. <Ninth aspect> A transfer apparatus according to any one of the first to eighth embodiments, characterized in that the operating member has a disc-shaped main body, and the entire circumference of the main body is covered by the front cover of the transfer unit. <Tenth aspect> A transfer apparatus according to any one of the first to ninth embodiments, characterized in that the functional member is a process cartridge unit that forms a toner image on the sheet member. <11th aspect> A transfer apparatus according to any one of the first to tenth embodiments, characterized in that the functional members are arranged in multiple quantities. <Twelfth aspect> An image forming apparatus characterized by having a transfer device according to any one of the first to eleventh embodiments. [Explanation of Symbols]

[0138] 1: Image forming apparatus 1-1: First pressing member 1-3-1: Hard plate-like part 1-3-2: Soft felt part 1-3-3: Rotating part (cam groove) 1A: Image forming part 1B: Paper feed unit 1B1: Paper feed cassette 1B2: Transport roller 1C: Document scanning unit 1C1: Document holder 1C2: Scanner 1C3: Automatic document feeder 2: Intermediate transfer belt 2: Intermediate transfer belt (belt component) 2-1~2-5: PCDU (functional component) 2A~2C: Roller 3K, 3Y, 3M, 3C, 3T: Photoconductor 4-1, 4-2: Second retaining member; 4-1-1, 4-2-1: Slotted hole 4-1-2, 4-2-2: Pins; 4-1-3: Retaining pins 5: Writing device 5-2: Slider 5-2-1: Pin 5-2-2: Cam Follower 5-2-3: Tension spring 6: Developing device 7: Primary transfer roller 7-1, 7-2: Cam 8: Connecting shaft 8-1, 8-2: Fixing pins 9: Secondary transfer device 9A: Secondary transfer roller 9a: Pin 10K, 10Y, 10M, 10C, 10T: Imaging section 11: Fixing device 11a, 12a: Pins 13: Paper output section 14: Rotating shaft 14-1: Cam 15: Slotted hole 16: Operating lever (operating component) 16a: Knob 16b: Main body 16c: Stepped section 17: Front slider 17a: Insertion part 17b~17d: Pin 18: Spring 19-1: Primary transfer roller 20: Transfer unit 20-1: Front cover 20-2: Notch 21: Rotating member 21A, 33A: Driven rollers 21a: Pivot point 21b: Positioning part 22: Detection sensor 22a: Pressing part 23: Cam follower 31: Cam component 31a: Rotating shaft 33: Rotating member 33A: Driven roller 33a: Pivot point 33b: Hole 34: Rotating member 34a: Pivot point 34b: Hole 35: Spring 36: Come Follower 37: First arm 37a: Pivot 37b: One end 37c1, 37c2: Gripping part 38: Second arm 38a, 38b: Slotted holes 39: Spring 40: Bearing 40a: Parallel pin 41: Bearing 42: Step screw 43a: Pivot point 43b: Stud 43c: Pin 44a: Hook 44d: Bent section 45: Spring 50: Tension spring 60: Thrust stopper member 60a: Contact portion 60b: Regulator 62: Spring 63: Regulating member 63a: Hole 64: Stud RP: Reversal conveyor path [Prior art documents] [Patent Documents]

[0139] [Patent Document 1] Patent No. 6394151

Claims

1. A transfer unit comprising a belt member for transporting a sheet member and a first pressing member for suppressing the curvature of the widthwise end of the belt member, wherein the transfer unit is detachably arranged to the main body of the device in the widthwise direction of the belt member, and the first pressing member is configured to be movable between an operating position that suppresses the curvature of the widthwise end of the belt member and a non-operating position spaced apart from the widthwise end of the belt member, A transfer apparatus having a functional member that is detachably arranged to the main body of the apparatus in the width direction of the belt member, adjacent to the belt member of the transfer unit, The functional member is configured to be immovable from the main body of the device by a second retaining member, and the second retaining member is configured to be movable between an operating position that prevents the functional member from being removed and a non-operating position that allows it to be removed. A transfer apparatus characterized in that the first pressing member and the second pressing member are configured to be movable between an operating position and a non-operating position by a common operating member, and the operating member is switchable between a first switching position for selecting the non-operating position of the first pressing member and the operating position of the second pressing member, and a second switching position for selecting the operating position of the first pressing member and the non-operating position of the second pressing member.

2. The transfer apparatus according to claim 1, characterized in that the second pressing member is disposed on the transfer unit.

3. The transfer apparatus according to claim 2, characterized in that the operating member is disposed on the transfer unit.

4. The transfer apparatus according to claim 3, comprising a transfer unit and a functional member and a transfer mechanism for bringing the transfer unit and the functional member into and out of contact, wherein the transfer mechanism is configured to be operated by the operating member.

5. The transfer apparatus of claim 4, characterized in that the operating member is biased from the second switching position to the first switching position by a biasing member, and is held in the second switching position against the biasing force of the biasing member.

6. The transfer apparatus of claim 4, characterized in that the operating member is held in the second switching position by the frictional force between a cam connected to the rotation axis of the operating member and a cam follower in contact with the cam.

7. The transfer apparatus according to claim 1, characterized in that the operating member is connected to the first pressing member via a first link mechanism and to the second pressing member via a second link mechanism.

8. The transfer apparatus according to claim 4, characterized in that the operating member is connected to the connecting / separating mechanism via a third link mechanism.

9. The transfer apparatus according to claim 1, characterized in that the operating member has a disc-shaped main body, and the entire circumference of the main body is covered by the front cover of the transfer unit.

10. The transfer apparatus according to claim 1, characterized in that the functional member is a process cartridge unit that forms a toner image on the sheet member.

11. The transfer apparatus according to claim 1, characterized in that a plurality of the functional members are arranged.

12. An image forming apparatus characterized by having a transfer device according to any one of claims 1 to 11.

Images