Image forming apparatus

Abstract

The present disclosure relates to an image forming apparatus including: a belt member; a first transfer roller; a second transfer roller; a tensioning unit including a tensioning member; a guide member configured to move between a guide position and a path opening position; an opening / closing member configured to move between a closed position and an open position; and a support member configured to move in linkage with the opening / closing member, and configured to support the guide member. The support member is configured to engage with the tensioning unit when the opening / closing member is positioned in the closed position to position the guide member relative to the tensioning member while positioning the guide member in the guide position, and the support member is configured to position the guide member in the path open position when the opening / closing member is positioned in the open position.

Description

Technical Field

[0001] The present disclosure relates to an imaging apparatus for forming an image on a sheet. Background Art

[0002] According to Japanese Patent Application Laid-Open No. 2013-114209, there is proposed an imaging apparatus including an intermediate transfer belt wound around a driving roller, a secondary transfer opposing roller, and a driven roller, and a lower transfer guide and an upper transfer guide for guiding a recording material toward the intermediate transfer belt. The lower transfer guide and the upper transfer guide are positioned and fixed by a guide support member, and the guide support member is rotatably supported by a rotation shaft of the driven roller. Accordingly, the guide support member moves according to the position of the driven roller, and the lower transfer guide and the upper transfer guide fixed to the guide support member also move following the movement of the driven roller. Thereby, the positional relationship between the recording material entering the secondary transfer portion and the intermediate transfer belt is maintained, and image defects are suppressed.

[0003] However, both the lower transfer guide and the upper transfer guide described in Japanese Patent Application Laid-Open No. 2013-114209 are fixed to the guide support member, and the transfer path formed by the lower transfer guide and the upper transfer guide cannot be opened. Therefore, there is a problem in the jam processing performance. Summary of the Invention

[0004] According to one aspect of the present disclosure, an imaging device includes: a belt member, the belt member is annular and is configured to carry a colorant image; a first transfer roller, the first transfer roller is configured to contact the inner peripheral surface of the belt member; a second transfer roller, the second transfer roller is configured to form a transfer nip portion together with the first transfer roller via the belt member, the second transfer roller is configured to transfer the colorant image on the belt member to the sheet in the transfer nip portion while conveying the sheet in the sheet conveying direction; a tensioning unit, the tensioning unit including a tensioning member, the tensioning member being arranged upstream of the transfer nip portion in the sheet conveying direction and being configured to tension the belt member by pressing the inner peripheral surface of the belt member a belt member, a guide member configured to guide the sheet and form a conveying path through which the sheet passes, the guide member configured to move between a guide position and a path opening position, in which the guide member guides the sheet toward the transfer nip, and in which the guide member opens the conveying path; an opening / closing member configured to move between a closing position and an opening position, the opening / closing member configured to open the conveying path by moving from the closing position to the opening position; and a supporting member configured to move in conjunction with the opening / closing member and configured to support the guide member. The supporting member is configured to engage with the tensioning unit when the opening / closing member is positioned at the closing position to position the guide member relative to the tensioning member while positioning the guide member at the guiding position, and the supporting member is configured to position the guide member at the path opening position when the opening / closing member is positioned at the opening position.

[0005] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1A is an overall schematic diagram showing the image forming apparatus in a state where the door unit is closed.

[0007] Figure 1B : is an overall schematic diagram showing the image forming apparatus in a state where the door unit is opened.

[0008] Figure 2 is a perspective view showing a joining unit according to the first embodiment.

[0009] Figure 3A is a side view showing the engagement unit when the door is positioned in a closed position.

[0010] Figure 3BIt is a side view of the engaging unit when the door is positioned at the open position.

[0011] Figure 4A It is a side view of the engaging unit according to the second embodiment when the door is positioned at the closed position.

[0012] Figure 4B It is a side view of the engaging unit when the door is positioned at the open position.

[0013] Figure 5A It is a side view of the engaging unit according to the third embodiment when the door is positioned at the closed position.

[0014] Figure 5B It is a side view of the engaging unit when the door is positioned at the open position.

[0015] Figure 6A It is a side view of the engaging unit according to the fourth embodiment when the door is positioned at the closed position.

[0016] Figure 6B It is a side view of the engaging unit when the door is positioned at the open position. Detailed Description First Embodiment

[0017] Overall Configuration

[0018] First, the first embodiment of the present disclosure will be described. Figure 1A It is an overall schematic view of the imaging device 100 in a state where the door unit 90 is closed, and Figure 1B It is an overall schematic view of the imaging device 100 in a state where the door unit 90 is open.

[0019] As Figure 1A and 1B shown, the imaging device 100 is a laser beam printer of an electrophotographic system. Note that the imaging device refers to a device including, for example, a printer, a copier, a fax machine, and a multifunction machine, and forms an image on a sheet used as a recording medium based on image information input from an external personal computer (PC) or image information read from an original. In addition, although sometimes an optional feeder, an image reading device, a sheet processing device, etc. are connected to the imaging device in addition to the main body having an imaging function, the entire system to which these auxiliary devices are connected is also a type of imaging device.

[0020] The image forming apparatus 100 includes an image forming unit 20 that forms an image on a sheet P, a sheet feeding device 40, a fixing unit 80, and a sheet discharging roller pair 85. The image forming unit 20 includes four process cartridges PY, PM, PC, and PK that respectively form toner images of four colors, which are yellow (Y), magenta (M), cyan (C), and black (K), an exposure unit 3, and an intermediate transfer device 10.

[0021] Note that, except for the colors of the formed images, the four process cartridges PY, PM, PC, and PK have the same configuration. Therefore, only the configuration and image forming process of the process cartridge PY will be described, and the descriptions of the process cartridges PM, PC, and PK will be omitted here.

[0022] The process cartridge PY includes a photosensitive drum 1, a charging roller 2, and a developing roller 4. The photosensitive drum 1 is formed by applying an organic photoconductive layer to the outer periphery of an aluminum cylinder and is rotated by a drive motor (not shown).

[0023] The intermediate transfer device 10 disposed below the four process cartridges PY, PM, PC, and PK includes an endless intermediate transfer belt 11. The intermediate transfer belt 11 serving as a belt member is tensioned by a drive roller 13, a secondary transfer opposing roller 14, and a tension roller 15 and is rotated by the drive roller 13. That is, the drive roller 13, the secondary transfer opposing roller 14, and the tension roller 15 are in contact with the inner peripheral surface 11b of the intermediate transfer belt 11. In addition, primary transfer rollers 12Y, 12M, 12C, and 12K are disposed inside the intermediate transfer belt 11. A secondary transfer roller 51 serving as a second transfer roller is disposed across the intermediate transfer belt 11 on the side opposite to the secondary transfer opposing roller 14 serving as a first transfer roller. The secondary transfer roller 51 and the secondary transfer opposing roller 14 form a transfer nip N through the intermediate transfer belt 11.

[0024] The fixing unit 80 includes a fixing film 81 heated by a heater and a pressure roller 82 that is in pressure contact with the fixing film 81. The sheet feeding device 40 is disposed in the lower part of the image forming apparatus 100 and includes a cassette 41 that stores the sheet P and a feeding roller 42.

[0025] The image forming apparatus 100 includes an apparatus main body 100A that houses the process cartridges PY, PM, PC, and PK and a door unit 90 that is openably supported by the apparatus main body 100A. The door unit 90 includes a door 92 that can pivot about a pivot shaft 91 as a center and a secondary transfer device 50 that is supported by the door 92 serving as an opening / closing member with a certain margin. In other words, the door unit 90 and the door 92 are openably supported with respect to the apparatus main body 100A between a closed position and an open position and are moved to the open position when opening a conveyance path CP, as described below.

[0026] The secondary transfer device 50 includes a secondary transfer roller 51, a pressing member 54 that presses the secondary transfer roller 51 toward the secondary transfer opposing roller 14, and a conveyance guide 52. The pressing member 54 is constituted by a spring, for example, a compression spring, but is not limited to a spring and may be other elastic members such as rubber or sponge. The conveyance guide 52 can move to a guide position where the conveyance guide 52 guides the sheet toward the transfer clamping portion and forms a conveyance path CP through which the sheet P passes together with the intermediate transfer belt 11 (see Figure 1A ), and a path opening position where the conveyance guide 52 guides to open the conveyance path CP (see Figure 1B ). That is, the conveyance guide 52 as a guiding member is positioned at the guide position when the door 92 is positioned at the closed position, and is positioned at the path opening position when the door 92 is positioned at the open position. Further, when the door 92 is positioned at the closed position, the secondary transfer roller 51 is pressed toward the secondary transfer opposing roller 14 by the pressing member 54 and is positioned relative to the secondary transfer opposing roller 14.

[0027] Next, the imaging operation of the imaging device 100 configured as described above will be described. When image information is input from, for example, a PC (not shown) to the exposure unit 3, a laser corresponding to the image signal is irradiated from the exposure unit 3 onto the photosensitive drum 1 of the process cartridge PY.

[0028] At this time, the surface of the photosensitive drum 1 has been previously uniformly charged to a predetermined polarity and potential, and an electrostatic latent image is formed on the surface by irradiating with the laser from the exposure unit 3. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing roller 4, and a toner image of yellow (Y) is formed on the photosensitive drum 1.

[0029] Similarly, a laser is also irradiated from the exposure unit 3 onto the respective photosensitive drums of the process cartridges PM, PC, and PK, and toner images of magenta (M), cyan (C), and black (K) are formed on the respective photosensitive drums. The toner image of each color formed on each photosensitive drum is transferred onto the intermediate transfer belt 11 by the primary transfer rollers 12Y, 12M, 12C, 12K, and is conveyed to the transfer clamping portion N by being carried by the intermediate transfer belt 11 rotated by the driving roller 13. It should be noted that the imaging process of each color is performed at the moment when the toner image is overlapped on the upstream toner image that has been primarily transferred onto the intermediate transfer belt 11.

[0030] In parallel with this imaging process, the sheet P stored in the sheet feeding device 40 is sent by the feeding roller 42 serving as a feeding unit. Then, the sheet P fed by the feeding roller 42 and passing through the conveyance path CP is guided by the conveyance guide 52 to the transfer nip N. The conveyance guide 52 may contact the second surface (non-printing surface) of the sheet P, which is opposite to the first surface (printing surface) onto which the toner image is transferred by the transfer nip N. By the secondary transfer bias applied to the secondary transfer roller 51, the full-color toner image on the intermediate transfer belt 11 is transferred onto the sheet P at the transfer nip N. That is, the toner image on the intermediate transfer belt 11 is transferred onto the sheet P at the transfer nip N in a state where the sheet P is conveyed in the sheet conveyance direction D1.

[0031] Through the fixing film 81 and the pressure roller 82 of the fixing unit 80, predetermined heat and pressure are applied to the sheet P onto which the toner image has been transferred, and the toner is melted and bonded (fixed). The sheet P that has passed through the fixing unit 80 is discharged to the sheet discharge tray 86 by the sheet discharge roller pair 85.

[0032] Note that although the imaging device 100 of this embodiment is configured to print only on one side of the sheet P, it is not limited thereto. For example, the imaging device 100 may include a duplex conveyance path that guides the sheet P to the transfer nip N again while flipping the sheet P after a toner image has been formed on the first surface of the sheet P. As described above, the imaging device 100 may be configured to form toner images on both the first and second surfaces of the sheet P.

[0033] Bonding unit

[0034] Next, the bonding unit 70 will be described using Figures 2 to 3B FIGs. Figure 2 FIG. 16 is a perspective view showing the bonding unit 70 according to the first embodiment. Figure 3A FIG. 18 is a side view showing the bonding unit 70 when the door 92 is positioned at the closed position. Figure 3B FIG. 20 is a side view showing the bonding unit 70 when the door 92 is positioned at the open position.

[0035] As Figure 2 shown, the bonding unit 70 includes first support members 21L and 21R, pressing members 31L and 31R, second support members 61L and 61R, and pressing members 71L and 71R. These members are arranged in pairs transversely in the width direction W orthogonal to the sheet conveyance direction D1, and the subscripts "L" and "R" attached to the reference numerals indicate whether they are located on one side or the other side in the width direction W. In addition, these pairs of members have the same configuration, so that when relevant, only one of the pair may be described, and the description of the other may sometimes be omitted.

[0036] The first support members 21L and 21R are supported by a frame (not shown) of the intermediate transfer device 10 so as to be movable in the direction of arrow A, and rotatably support two end portions of the tension roller 15. The tension roller 15 serving as a tension member is disposed upstream of the transfer nip N in the sheet conveying direction D1. The pressing members 31L and 31R press the first support members 21L and 21R, respectively, so that the tension roller 15 is pressed toward the inner peripheral surface 11b of the intermediate transfer belt 11. These tension roller 15, first support members 21L and 21R, and pressing members 31L and 31R constitute a tension unit 30.

[0037] With this configuration, the tension roller 15 applies a predetermined tension to the intermediate transfer belt 11, and the position of the tension roller 15 is determined by the balance between the pressing forces of the pressing members 31L and 31R and the tension of the intermediate transfer belt 11. Further, when determining the position of the tension roller 15, the position of the surface 11a of the intermediate transfer belt 11 tensioned between the secondary transfer opposing roller 14 and the tension roller 15 is determined.

[0038] The second support members 61L and 61R are pivotally supported by two end portions of the rotary shaft 51a of the secondary transfer roller 51, and are pressed toward the tension roller 15 and the first support members 21L and 21R by the pressing members 71L and 71R. That is, the second support members 61L and 61R are linked to the door 92 that supports the secondary transfer device 50. In other words, the second support members 61L and 61R are pivotally supported by the door 92. Two end portions of the transfer guide 52 in the width direction W are supported by the second support members 61L and 61R. Although the pressing members 31L, 31R, 71L, and 71R are constituted by, for example, springs (e.g., compression springs), they are not limited to springs and may be other elastic members (e.g., rubber or sponge).

[0039] The first support members 21L and 21R include abutting surfaces 21La and 21Ra, and these abutting surfaces 21La and 21Ra extend in a direction intersecting the moving direction MD in which the door 92 moves from the closed position to the open position. Further, the second support members 61L and 61R include protrusions 61La and 61Ra that can contact and separate from the abutting surfaces 21La and 21Ra. The protrusions 61La and 61Ra extend in the width direction W.

[0040] Next, although Figure 3A and 3B will be used to describe the operation of the engaging unit 70, only one side (the side with the subscript "L") of the engaging unit 70 will be described, and the description of the other side (the side with the subscript "R") will be omitted. As Figure 3AAs shown, when the door 92 is positioned at the closed position, the projection 61La abuts against the abutting surface 21La. At this time, since the second support member 61L is pushed by the pushing member 71L that serves as the first pushing member, the projection 61La is pressed against the abutting surface 21La.

[0041] That is, the first and second support members 21L and 61L are joined to each other at the projection 61La and the abutting surface 21La. Therefore, the transfer guide 52 supported by the second support member 61L serving as a support member is positioned relative to the tension roller 15 supported by the first support member 21L serving as a joined member.

[0042] Since the position of the projection 61La follows the position change of the first support member 21L in the direction of arrow A, even when the position of the tension roller 15 changes, the relative position of the transfer guide 52 with respect to the tension roller 15 remains almost unchanged. Therefore, the positional relationship between the surface 11a of the intermediate transfer belt 11 that follows the movement of the tension roller 15 and the sheet P guided by the transfer guide 52 on the non-printing surface side thereof is maintained.

[0043] As described above, when the door 92 is positioned at the closed position as Figure 3A shown, the first and second support members 21L and 61L are joined. According to this configuration, the transfer guide 52 is positioned relative to the tension roller 15 so as to be positioned at a guiding position that forms the transfer path CP together with the surface 11a of the intermediate transfer belt 11. Therefore, it is possible to reduce the positional deviation of the contact position P1 where the sheet P guided by the transfer guide 52 starts to contact the surface 11a of the intermediate transfer belt 11.

[0044] As a result, the occurrence of image defects at a position upstream of the transfer clamping portion N in the sheet transfer direction D1 can be suppressed. For example, in the case where the contact position P1 is positioned too close to the transfer clamping portion N and falls within a region where the electric field for secondary transfer is strong, there is a risk that the toner image carried on the intermediate transfer belt 11 will be disturbed due to discharge occurring between the intermediate transfer belt 11 and the sheet P. In addition, in the case where the contact position P1 is too far from the transfer clamping portion N and the distance where the sheet P and the intermediate transfer belt 11 scrape against each other is extended, there is a risk of image defects due to vibrations and friction generated by the scraping between the sheet P and the intermediate transfer belt 11. In the present embodiment, since the transfer guide 52 is positioned relative to the tension roller 15, the contact position P1 can be stably maintained within a predetermined correct distance from the transfer clamping portion N, and image defects as described above can be suppressed.

[0045] In addition, when the pressing members 31L and 71L press the first and second support members 21L and 61L in opposite directions to each other, the pressing force of the pressing member 71L is set to be smaller than the pressing force of the pressing member 31L. Therefore, the tension roller 15 can press the inner peripheral surface 11b of the intermediate transfer belt 11 without difficulty. In addition, the pressing forces of the pressing members 31L and 71L are set such that even when a sheet P having a relatively high rigidity (e.g., thick paper) contacts the transfer guide 52, the transfer guide 52 does not move due to the reaction force from the sheet P.

[0046] Next, as Figure 3B shown, when the door 92 is positioned at the open position, the projection 61La is separated from the abutting surface 21La. That is, the tension unit 30 including the first support member 21L and the second support member 61L are separated from each other, and the positioning of the transfer guide 52 relative to the tension roller 15 is released.

[0047] Then, the transfer guide 52 moves together with the door 92 and the second support member 61L, and is positioned at the path open position to open the transfer path CP. In other words, the transfer guide 52 can move to the guiding position ( Figure 3A position) that forms the transfer path CP and the path open position ( Figure 3B position) for opening the transfer path CP, and the transfer guide moves from the guiding position to the path open position by moving the door 92 from the closed position to the open position. With this configuration, it is possible to easily handle a sheet jammed in the transfer path CP, and the jam handling performance can be improved.

[0048] As described above, in the present embodiment, when the door 92 is positioned at the closed position, the transfer guide 52 can be positioned at the guiding position relative to the tension roller 15, and image defects can be suppressed. In addition, when the door 92 is positioned at the open position, the transfer guide 52 moves together with the door 92 to open the transfer path CP, and the jam handling performance can be improved. In addition, since the abutting surface 21La of the first support member 21L extends in a direction substantially orthogonal to the direction of the arrow A, the engagement relationship between the projection 61La that pivots about the rotation axis 51a as the center and the abutting surface 21La that linearly moves in the direction of the arrow A can be maintained with a simple configuration.

[0049] Note that, although in this embodiment, the abutting surface 21La serving as the surface is disposed on the first support member 21L, and the protrusion 61La serving as the abutting portion is disposed on the second support member 61L, this is not limitative. For example, the protrusion 61La may be disposed on the first support member 21L, and the abutting surface 21La may be disposed on the second support member 61L. Additionally, the abutting surface 21La may be disposed on the rotating shaft of the tension roller 15 or the like. That is, the abutting surface 21La may be disposed on either the tension unit 30 or the second support member 61L, and the protrusion 61La may be disposed on the other of the tension unit 30 or the second support member 61L. Second Embodiment

[0050] Next, a second embodiment of the present disclosure will be described, in which the configuration of the engaging unit 70 in the first embodiment is changed. Therefore, configurations similar to those in the first embodiment will be described by omitting the illustrations or by adding the same reference numerals in the drawings. Figure 4A is a side view showing the engaging unit 170 according to the second embodiment when the door 92 is positioned at the closed position, and Figure 4B is a side view showing the engaging unit 170 when the door 92 is positioned at the open position.

[0051] As Figure 4A shown, the engaging unit 170 according to the second embodiment includes a first support member 22L, a second support member 62L, and a pressing member 31L. Note that, similar to the first embodiment, although the first support member 22L, the second support member 62L, and the pressing member 31L are arranged in pairs laterally in the width direction W, only one side in the width direction W will be described.

[0052] The first support member 22L as the member to be engaged is supported by a frame (not shown) of the intermediate transfer device 10 so as to be movable in the direction of arrow A, and rotatably supports the tension roller 15. The pressing member 31L presses the first support member 22L to press the tension roller 15 toward the inner peripheral surface 11b of the intermediate transfer belt 11. With this configuration, the tension roller 15 applies a predetermined tension to the intermediate transfer belt 11, and the position of the tension roller 15 is determined by the balance between the pressing force of the pressing member 31L and the tension of the intermediate transfer belt 11. These tension roller 15, first support member 22L, and pressing member 31L constitute the tension unit 230.

[0053] The second support member 62L is pivotally supported by the rotating shaft 51a of the secondary transfer roller 51 and is not pressed by a pressing member as in the first embodiment. The transfer guide 52 is supported by the second support member 62L.

[0054] The first support member 22L includes a groove 22La formed to be open on one side. The groove 22La extends in a direction intersecting with the moving direction MD in which the door 92 moves from the closed position to the open position. The moving direction MD also intersects with the direction of arrow A which is the moving direction of the first support member 22L. In addition, the second support member 62L includes a projection 62La that can engage with and disengage from the groove 22La. The projection 62La extends in the width direction W.

[0055] Next, the operation of the engagement unit 170 will be described. As Figure 4A shown, when the door 92 is positioned at the closed position, the projection 62La engages with the groove 22La. At this time, since the groove 22La extends in a direction intersecting with the direction of arrow A and the moving direction MD, the first support member 22L and the second support member 62L are in an interlocking relationship. That is, the first support member 22L and the second support member 62L are engaged with each other at the projection 62La and the groove 22La. Therefore, the transfer guide 52 supported by the second support member 62L is positioned at the guiding position relative to the tension roller 15 supported by the first support member 22L.

[0056] Since the position of the projection 62La follows the change in the position of the first support member 22L supporting the tension roller 15 in the direction of arrow A, even when the position of the tension roller 15 changes, the relative position of the transfer guide 52 with respect to the tension roller 15 remains almost unchanged. Therefore, the positional relationship between the surface 11a of the intermediate transfer belt 11 that moves following the tension roller 15 and the sheet P guided by the transfer guide 52 on the non-printing surface side thereof is maintained. Therefore, the positional deviation of the contact position P1 where the sheet P guided by the transfer guide 52 starts to contact the surface 11a of the intermediate transfer belt 11 can be reduced.

[0057] Next, when the door 92 moves from the closed position to the open position as Figure 4B shown, the second support member 62L pivots about the rotation axis 51a as the center, and the projection 62La withdraws from the groove 22La. When the engagement between the projection 62La and the groove 22La is released, the second support member 62L is maintained in an attitude where the center of gravity G of the second support member 62L and the rotation axis 51a are aligned in a straight line in the vertical direction. Then, when the door 92 is positioned at the open position, the projection 62La is separated from the groove 22La. That is, the tension unit 230 including the first support member 22L and the second support member 62L are separated from each other, and the positioning of the transfer guide 52 with respect to the tension roller 15 is released.

[0058] Then, the transfer guide 52 moves together with the door 92 and the second support member 62L, and is positioned at the path opening position to open the transfer path CP. Thus, it is possible to easily handle the sheet jammed in the transfer path CP, and the jam handling performance can be improved.

[0059] Note that when the door 92 is closed again from the open position to the closed position, the projection 62La of the second support member 62L is guided toward the groove 22La by the guide surface 22Lb of the first support member 22L. Then, the second support member 62 pivots about the rotation axis 51a, and the projection 62La engages with the groove 22La.

[0060] As described above, also in the second embodiment, similar to the first embodiment, both suppression of image defects and improvement of jam handling performance can be achieved. In addition, since the pressing member for pressing the second support member 62L can be eliminated, cost reduction can be achieved.

[0061] Note that although in the present embodiment, the groove 22La is arranged in the first support member 22L, and the projection 62La serving as the engaging portion is arranged on the second support member 62L, this is not limiting. For example, the projection 62La can be arranged on the first support member 22L, and the groove 22La can be arranged in the second support member 62L. In addition, the groove 22La can be arranged on the rotation shaft of the tension roller 15 or the like. That is, it is acceptable if the groove 22La is arranged on either the tension unit 230 or the second support member 62L while the projection 62La is arranged on the other of the tension unit 230 or the second support member 62L. Third Embodiment

[0062] Next, a third embodiment of the present disclosure will be described, in which the configuration of the engaging unit 70 of the first embodiment is changed. Therefore, the configurations similar to those of the first embodiment will be described by omitting the illustrations or by adding the same reference numerals to the drawings. Figure 5A is a side view showing the engaging unit 270 according to the third embodiment when the door 92 is positioned at the closed position, and Figure 5B is a side view showing the engaging unit 270 when the door 92 is positioned at the open position.

[0063] As Figure 5AAs shown, the joining unit 270 according to the third embodiment includes a first support member 21L, a second support member 63L, and pressing members 31L and 71L. Note that, although similar to the first embodiment, the first support member 21L, the second support member 63L, and the pressing members 31L and 71L are arranged to be laterally paired in the width direction W, only one side in the width direction W will be described. In this embodiment, in particular, the structure and function of the second support member 63L are different from those of the first embodiment.

[0064] The second support member 63L serving as a support member is supported by the frame 55 of the secondary transfer device 50 so as to be slidably movable in the direction of arrow B, and is pressed by the pressing member 71L toward the tension roller 15 and the first support member 21L. In other words, the second support member 63L is slidably supported by the door 92. The conveyance guide 52 is supported by the second support member 63L. The second support member 63L includes a projection 63La that can contact and separate from the contact surface 21La of the first support member 21L. The projection 63La extends in the width direction W. Note that the direction of arrow B is substantially the same as the direction of arrow A, which is the linear motion direction of the first support member 21L, in a state where the door 92 is positioned at the closed position.

[0065] Next, the operation of the joining unit 270 will be described. As Figure 5A shown, when the door 92 is positioned at the closed position, the projection 63La contacts the contact surface 21La. At this time, by pressing the second support member 63L by the pressing member 71L, the projection 63La is pressed against the contact surface 21La.

[0066] That is, the first support member 21L and the second support member 63L are joined to each other at the projection 63La and the contact surface 21La. Therefore, the conveyance guide 52 supported by the second support member 63L is positioned relative to the tension roller 15 supported by the first support member 21L.

[0067] Since the position of the projection 63La follows the position change of the first support member 21L that supports the tension roller 15 in the direction of arrow A, even when the position of the tension roller 15 changes, the relative position of the conveyance guide 52 with respect to the tension roller 15 remains unchanged. Therefore, the positional relationship between the surface 11a of the intermediate transfer belt 11 that moves following the tension roller 15 and the sheet P whose non-printing surface side is guided by the conveyance guide 52 is maintained. Therefore, the positional deviation of the contact position P1 where the sheet P guided by the conveyance guide 52 starts to contact the surface 11a of the intermediate transfer belt 11 can be reduced.

[0068] Next, when the door 92 moves from the closed position to as Figure 5BWhen in the open position shown, after the pressing members 31L and 71L have returned to their natural states, the projection 63La is separated from the abutment surface 21La. That is, the tensioning unit 30 including the first support member 21L and the second support member 63L are separated from each other, and the positioning of the conveyance guide 52 relative to the tensioning roller 15 is released.

[0069] Then, the conveyance guide 52 moves together with the door 92 and the second support member 63L, and is positioned at the path open position to open the conveyance path CP. Thereby, it is possible to easily handle the sheet P jammed in the conveyance path CP, and the jam handling performance can be improved.

[0070] As described above, also in the third embodiment, similar to the first embodiment, both suppression of image defects and improvement of jam handling performance can be achieved. In addition, since when the door 92 is positioned at the closed position, the arrow B direction which is the linear movement direction of the conveyance guide 52 is substantially the same as the arrow A direction which is the linear movement direction of the tensioning roller 15, the conveyance guide 52 can be accurately positioned relative to the tensioning roller 15. Fourth Embodiment

[0071] Next, a fourth embodiment of the present disclosure will be described. In the fourth embodiment, the configuration of the engaging unit 70 of the first embodiment is changed. Therefore, the configurations similar to those of the first embodiment will be described by omitting the illustrations or by adding the same reference numerals to the drawings. Figure 6A is a side view showing the engaging unit 370 according to the fourth embodiment when the door 92 is positioned at the closed position, and Figure 6B is a side view showing the engaging unit 370 when the door 92 is positioned at the open position.

[0072] As Figure 6A shown, the engaging unit 370 according to the fourth embodiment includes a first support member 24L, a second support member 64L, and pressing members 31L and 71L. Note that although similar to the first embodiment, the first support member 24L, the second support member 64L, and the pressing members 31L and 71L are arranged in pairs laterally in the width direction W, only one side in the width direction W will be described.

[0073] The first support member 24L as a member to be joined is supported by a frame (not shown) of the intermediate transfer device 10 so as to be movable in the direction of arrow A, and rotatably supports the tension roller 15. The pressing member 31L presses the first support member 24L to press the tension roller 15 toward the inner peripheral surface 11b of the intermediate transfer belt 11. With this configuration, the tension roller 15 applies a predetermined tension to the intermediate transfer belt 11, and the position of the tension roller 15 is determined by the balance between the pressing force of the pressing member 31L and the tension of the intermediate transfer belt 11. These tension roller 15, first support member 24L, and pressing member 31L constitute a tension unit 430.

[0074] A second support member 64L serving as a support member is pivotally supported by a rotating shaft 51a of the secondary transfer roller 51, and is pressed by a pressing member 71L toward the tension roller 15 and the first support member 24L. In addition, the second support member 64L includes an elongated hole 64Lb extending in the direction of arrow C, and the rotating shaft 51a is inserted into the elongated hole 64Lb. That is, the second support member 64L can move in the direction of arrow C relative to the rotating shaft 51a within the range of the elongated hole 64Lb. The conveyance guide 52 is supported by the second support member 64L.

[0075] The first support member 24L includes a first contact surface 24La extending in a first direction (a direction orthogonal to the direction of arrow x) intersecting the moving direction MD, and a second contact surface 24Lb, where the moving direction MD is the direction in which the second support member 64L moves when the door 92 moves from the closed position to the open position. The second contact surface 24Lb extends in a second direction (a direction orthogonal to the direction of arrow y) intersecting both the moving direction MD and the first direction. In addition, the second support member 64L includes a projection 64La that can contact and separate from the first contact surface 24La and the second contact surface 24Lb. The projection 64La extends in the width direction W serving as the sheet width direction, and when viewed in the width direction, the conveyance guide 52 is arranged to overlap the projection 64La.

[0076] Next, the operation of the joining unit 370 will be described. As Figure 6A shown, when the door 92 is positioned at the closed position, the projection 64La engages with the first contact surface 24La and the second contact surface 24Lb of the first support member 24L. At this time, since the second support member 64L is pressed by the pressing member 71L, the projection 64La presses against the first contact surface 24La and the second contact surface 24Lb in the directions of arrows x and y, respectively.

[0077] That is, the projection 64La of the second support member 64L is positioned relative to the first contact surface 24La and the second contact surface 24Lb of the first support member 24L, and the conveyance guide 52 supported by the second support member 64L is positioned relative to the tension roller 15. Since the position of the projection 64La follows the position change of the first support member 24L that supports the tension roller 15 in the direction of arrow A, the relative position of the conveyance guide 52 relative to the tension roller 15 remains unchanged even when the position of the tension roller 15 changes.

[0078] Specifically, in the present embodiment, the second support member 64L can move in the direction of arrow C, and the movement of the projection 64La in the direction of arrow C following the first contact surface 24La and the second contact surface 24Lb is absorbed by the elongated hole 64Lb. Moreover, since the conveyance guide 52 is arranged to overlap with the projection 64a when viewed in the width direction W, the conveyance guide 52 can be accurately positioned relative to the tension roller 15. Therefore, the positional relationship between the surface 11a of the intermediate transfer belt 11 that follows the movement of the tension roller 15 and the non-printing surface side of the sheet P guided by the conveyance guide 52 is maintained. Accordingly, the positional deviation of the contact position P1 where the sheet P guided by the conveyance guide 52 starts to contact the surface 11a of the intermediate transfer belt 11 can be reduced.

[0079] Next, when the door 92 moves from the closed position to the open position as Figure 6B shown, after the pressing members 31L and 71L have returned to their natural states, the projection 64La separates from the first contact surface 24La and the second contact surface 24Lb. That is, the tension unit 430 including the first support member 24L and the second support member 64L are separated from each other, and the positioning of the conveyance guide 52 relative to the tension roller 15 is released.

[0080] Then, the conveyance guide 52 moves together with the door 92 and the second support member 64L and is positioned at the path open position to open the conveyance path CP. Thereby, the sheet jammed in the conveyance path CP can be easily handled, and the sheet jam handling performance can be improved.

[0081] As described above, also in the fourth embodiment, similar to the first embodiment, both suppression of image defects and improvement of sheet jam handling performance can be achieved. In addition, when the door 92 is positioned at the closed position, the projection 64La of the second support member 64L that supports the conveyance guide 52 is positioned in two intersecting directions by the first contact surface 24La and the second contact surface 24Lb. Therefore, the conveyance guide 52 can be accurately positioned relative to the tension roller 15.

[0082] Note that, although in this embodiment, the first contact surface 24La and the second contact surface 24Lb are arranged on the first support member 24L, and the projection 64La serving as a raised portion is arranged on the second support member 64L, this is not limitative. For example, the projection 64La may be arranged on the first support member 24L, and the first contact surface 24La and the second contact surface 24Lb may be arranged on the second support member 64L. Additionally, the first contact surface 24La and the second contact surface 24Lb may be arranged on the rotation axis of the tension roller 15 or the like. That is to say, it is acceptable if the first contact surface 24La and the second contact surface 24Lb are arranged on either the tension unit 430 or the second support element 64L while the projection 64La is arranged on the other of the tension unit 430 or the second support element 64L. Other embodiments

[0083] Note that, although in any of the above embodiments, the transfer guide 52 is held by the secondary transfer device 50, this is not limitative. For example, the transfer guide 52 may be held by a member such as the door 92 that moves integrally with the door unit 90 instead of being held by the secondary transfer device 50.

[0084] Additionally, the transfer guide 52 may not be held by the door 92 but by the device main body 100A. In this case, the transfer guide 52 is movably supported by a frame or the like (not shown) of the device main body 100A and includes an engaging portion, and when the door 92 moves from the open position to the closed position, the engaging portion engages with the tension roller 15. Thus, the transfer guide 52 is positioned relative to the tension roller 15. On the other hand, it is acceptable to be configured such that when the door 92 moves from the closed position to the open position, the engaging portion disengages from the tension roller 15 and the transfer guide 52 moves to the path open position.

[0085] Additionally, although in any of the above embodiments, the transfer guide 52 moves between the guiding position and the path open position in linkage with the opening / closing of the door 92 that forms a part of the outer surface of the imaging device 100, this is not limitative. For example, it is acceptable that there is another opening / closing member between the door 92 and the device main body 100A, and the transfer guide 52 moves between the guiding position and the path open position in linkage with the opening / closing of this opening / closing member.

[0086] In addition, although in any of the above-mentioned embodiments, the conveying guide 52 forms the conveying path CP with the surface 11a of the intermediate transfer belt 11 at the guiding position, it is not limited thereto. For example, the conveying guide 52 may form the conveying path CP with other guide members arranged between the conveying guide 52 and the surface 1a of the intermediate transfer belt 11 at the guiding position. At this time, it is preferred that when the door 92 is positioned at the closed position, the other guide members are positioned relative to the tension roller 15 in conjunction with the conveying guide 52. In addition, when the door 92 is positioned at the open position, the positioning of the other guide members relative to the tension roller 15 may be released or may be maintained as long as the conveying path CP is opened.

[0087] In addition, although the tension roller is a roller rotatably driven by the intermediate transfer belt 11 in any of the above embodiments, it is not limited thereto. For example, a non-rotating member pressed against the inner peripheral surface 11 b of the intermediate transfer belt 11 may be used instead of the tension roller 15 .

[0088] In addition, although in any of the above embodiments, when the door 92 is positioned in the open position, the second support member (61L, 62L, 63L or 64L) is separated from the first support member (21L, 22L or 24L), it is not limited thereto. For example, when the door 92 is positioned in the open position, the second support member may be engaged with the first support member.

[0089] In addition, although in any of the above embodiments, the second supporting member (61L, 62L, 63L or 64L) is arranged independently of the conveying guide 52, it is not limited thereto. For example, the second supporting member and the conveying guide 52 may be formed integrally.

[0090] In addition, the above-described first to fourth embodiments may be freely combined. For example, in the second embodiment, it is acceptable to arrange the urging member 71L that urges the second supporting member 62L toward the tension roller 15.

[0091] Although the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An imaging device, comprising: a belt member which is endless and configured to carry a toner image; a first transfer roller configured to be in contact with an inner peripheral surface of the belt member; a second transfer roller configured to form a transfer nip portion with the first transfer roller via the belt member, the second transfer roller configured to transfer the toner image on the belt member to the sheet in the transfer nip portion while conveying the sheet in a sheet conveying direction; a tensioning unit including a tensioning member disposed upstream of the transfer nip in the sheet conveying direction and configured to tension the belt member by pressing an inner peripheral surface of the belt member; a guide member configured to guide the sheet and form a conveying path through which the sheet passes, the guide member configured to move between a guide position in which the guide member guides the sheet toward the transfer nip and a path opening position in which the guide member opens the conveying path; an opening / closing member configured to move between a closing position and an opening position, the opening / closing member configured to open the conveying path by moving from the closing position to the opening position; as well as a supporting member configured to move in conjunction with the opening / closing member and configured to support the guide member, wherein the support member is configured to engage with the tensioning unit when the opening / closing member is positioned in the closed position to position the guide member relative to the tensioning member while positioning the guide member in the guide position, and the support member is configured to position the guide member in the path opening position when the opening / closing member is positioned in the open position.

2. The imaging device according to claim 1, wherein The supporting member is configured to be separated from the tensioning unit when the opening / closing member is positioned at the open position. 3 . The image forming apparatus according to claim 1 , further comprising a first urging member configured to urge the supporting member toward the tension unit.

4. The imaging device according to claim 3, wherein: The tensioning unit comprises: an engaged member configured to support the tensioning member and to engage with the supporting member; and a second urging member configured to urge the engaged member toward the supporting member so that the tensioning member presses the inner peripheral surface of the belt member.

5. The imaging device according to claim 4, wherein: The urging force of the second urging member is greater than the urging force of the first urging member.

6. The imaging device according to claim 1, wherein Either the tension unit or the support member includes a surface extending in a direction intersecting a moving direction in which the support member moves when the opening / closing member moves from the closed position to the open position, and Wherein, the other of the tensioning unit or the supporting member comprises an abutment portion configured to abut against the surface when the opening / closing member is positioned in the closed position.

7. The imaging device according to claim 1, wherein: Either the tensioning unit or the supporting member includes a groove extending in a direction intersecting a moving direction in which the supporting member moves when the opening / closing member moves from the closing position to the opening position, and Wherein, the other of the tensioning unit or the supporting member includes an engaging portion configured to engage with the groove when the opening / closing member is positioned at the closed position.

8. The imaging device according to claim 7, wherein: Either the tensioning unit or the supporting member includes a guide surface configured to guide the engaging portion toward the groove when the opening / closing member moves from the open position to the closed position.

9. The imaging device according to claim 1, wherein: Either the tensioning unit or the supporting member includes a first contact surface extending in a first direction intersecting a moving direction in which the supporting member moves when the opening / closing member moves from the closed position to the open position, and a second contact surface extending in a second direction intersecting the moving direction and the first direction, and The other of the tensioning unit or the supporting member includes a protruding portion configured to contact the first contact surface and the second contact surface when the opening / closing member is positioned at the closed position.

10. The imaging device according to claim 9, wherein The guide member is arranged to overlap the convex portion when viewed in a width direction orthogonal to the sheet conveying direction when the opening / closing member is positioned at the closed position.

11. The imaging device according to claim 1, wherein The supporting member is pivotably supported by the opening / closing member.

12. The imaging device according to claim 1, wherein The supporting member is slidably movably supported by the opening / closing member.

13. The imaging device according to any one of claims 1 to 12, wherein: The opening / closing member is configured to rotatably support the second transfer roller.

14. The imaging device according to any one of claims 1 to 12, wherein: The opening / closing member is a door configured to form a part of an outer surface of the imaging device in the closed position.

15. The imaging device according to any one of claims 1 to 12, wherein: The tension member is a roller rotatably supported by the tension unit.

16. The imaging device according to any one of claims 1 to 12, wherein: The guide member is configured to form the transport path together with the belt member at the guide position.

17. The imaging device according to any one of claims 1 to 12, wherein: The guide member is configured to contact a second surface of the sheet, the second surface being opposite to a first surface onto which the toner image is transferred through the transfer nip.

Images