Image forming device

Abstract

To provide an image forming apparatus that can lock a unit removably attached to an apparatus main body to the apparatus main body and release the locking with a simple configuration.SOLUTION: An image forming apparatus comprises: a unit that is removably attached to a main body frame; and lock mechanisms that hold the unit in an attached state and can release the holding. The lock mechanisms each have a handle part, a lock member, and an urging member. The handle part is arranged on the unit and can reciprocate in the attachment direction and a removal direction of the unit. The lock member is arranged swingably with respect to the unit and has a hook part that can be engaged with an engagement target part formed on the main body frame. The urging member urges the lock member in a first direction in which the hook part is engaged with the engagement target part. When the handle part is moved to the removal direction, the lock member swings in the first direction and a second direction opposite thereto against an urging force of the urging member, and the engagement between the hook part and the engagement target part is released.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus including a unit such as an intermediate transfer unit that is detachable from the main body of the apparatus. [Background technology]

[0002] Various types of image forming apparatus have been proposed in the past. Among them is an intermediate transfer type image forming apparatus that includes an endless intermediate transfer belt that rotates in a predetermined direction and a plurality of image forming units arranged along the intermediate transfer belt, in which toner images are sequentially superimposed on the intermediate transfer belt by each image forming unit, and then transferred onto a recording medium all at once.

[0003] In the image forming apparatus of the intermediate transfer type as described above, the intermediate transfer belt, which has a shorter service life than the life of the apparatus body, needs to be replaced periodically. Therefore, a configuration in which the intermediate transfer unit including the intermediate transfer belt is detachable from the image forming apparatus body is widely used. In this case, the intermediate transfer unit can be fixed to the image forming apparatus body by operating a rotating lever or by fixing with a screw.

[0004] For example, Patent Document 1 discloses an image forming device having a handle member attached to one end of a rotating shaft and a locking member attached to the other end of the rotating shaft, in which the locking member rotates in accordance with the rotation of the handle member, thereby locking the unit to the device main body.

[0005] Patent Document 2 discloses an image forming apparatus including a unit that can be inserted and removed horizontally from a main frame, and a locking mechanism for the unit. The locking mechanism is arranged on the unit side so as to be reciprocable in a direction perpendicular to the insertion and removal direction, and includes a locking member having an engaging protrusion that can engage with an engaged portion on the main frame side, and a biasing member that biases the locking member in a first direction in which the engaging protrusion engages with the engaged portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-147977 A [Patent Document 2] JP 2017-194490 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the methods of Patent Documents 1 and 2, the operation of attaching and detaching the unit and the operation of releasing the locking mechanism must be performed separately, which poses the problem that there are many steps required for attaching and detaching the unit, reducing maintainability.

[0008] Although the above description has been given taking as an example the case where the intermediate transfer unit is attached to and detached from the main body of the apparatus, the same problems arise when other units are attached to and detached from the main body of the apparatus.

[0009] SUMMARY OF THE PRESENT DISCLOSURE In view of the above problems, an object of the present invention is to provide an image forming apparatus that is capable of locking and unlocking a unit that is detachable from the apparatus body with a simple configuration. [Means for solving the problem]

[0010] In order to achieve the above object, a first configuration of the present invention is an image forming apparatus including a unit that is detachable from a main body frame, and a locking mechanism that holds the unit in a state where it is attached to the main body frame and is capable of releasing the hold. The locking mechanism has a handle portion, a locking member, and a biasing member. The handle portion is disposed on the unit and is reciprocally movable in the mounting direction and removal direction of the unit. The locking member is disposed on the unit so as to be able to swing, and has a hook portion that is engageable with an engaged portion formed on the main body frame. The biasing member biases the locking member in a first direction in which the hook portion engages with the engaged portion. By moving the handle portion in the removal direction, the locking member swings against the biasing force of the biasing member in a second direction opposite to the first direction, and the engagement between the hook portion and the engaged portion is released, making it possible to remove the unit from the main body frame. Effect of the Invention

[0011] According to the first configuration of the present invention, the direction in which the handle is operated to release the locking mechanism and the direction in which the unit is removed are the same, so that the locking mechanism can be released and the unit can be removed simultaneously. Therefore, the user can release the lock of the unit from the main body frame with a simple operation without having to tighten screws or operate a rotating lever, and can smoothly replace the unit. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an internal configuration of an image forming apparatus 100 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the intermediate transfer unit 30 as viewed from the belt cleaning unit 19 side. [Diagram 3] FIG. 11 is a side view showing a state in which a cover member 38 is removed from a connecting frame 32 of the intermediate transfer unit 30. [Figure 4] FIG. 4 is a perspective view of the first handle portion 37 as viewed from the rear side of FIG. [Diagram 5] FIG. 3 is a perspective view of a lock member 41 disposed inside the cover member 38. [Figure 6] FIG. 4 is an enlarged view of the lock mechanism 40 in FIG. 3, showing a state in which the lock member 41 and the engaged portion 50 are engaged with each other. [Figure 7] 4 is a side cross-sectional view of the intermediate transfer unit 30 in the vicinity of the connection frame 32 in FIG. [Figure 8] FIG. 4 is a side view of the connecting frame 32, showing a state in which the first handle portion 37 has been lifted up from the state shown in FIG. [Figure 9] FIG. 9 is an enlarged view of the lock mechanism 40 in FIG. 8, showing a state in which the lock member 41 and the engaged portion 50 are disengaged from each other. [Figure 10] 9 is a side cross-sectional view of the intermediate transfer unit 30 in the vicinity of the connection frame 32 in FIG. 8. [Figure 11] FIG. 1 is a side view showing a state in which the intermediate transfer unit 30 is attached to the main body frame 101. [Figure 12] FIG. 11 is a side view showing a state immediately before the intermediate transfer unit 30 is removed from the main body frame 101. [Figure 13] FIG. 13 shows a state in which the inclined surface 45 of the hook portion 41b comes into contact with the engaged portion 50 as the connecting frame 32 of the intermediate transfer unit 30 descends. [Figure 14] FIG. 11 is a perspective view of a lock member 41 disposed inside a cover member 38 in an image forming apparatus 100 according to a second embodiment of the present invention; [Figure 15] FIG. 11 is a side view of the vicinity of the connecting frame 32 of the intermediate transfer unit 30 in the image forming apparatus 100 according to the second embodiment, showing a state in which the toner container 4a is placed on the container placement portion 33a. [Figure 16] FIG. 1 is a perspective view of a toner container; [Figure 17] FIG. 13 is a front view of the intermediate transfer unit 30 in which the toner container 4a is placed, viewed from the outside, in the vicinity of the connection frame 32, showing a state in which the intermediate transfer unit 30 is normally attached. [Figure 18] 18 is a front cross-sectional view of the vicinity of the protrusion 47 of the lock member 41 in FIG. 17. [Figure 19]FIG. 1 is a front view of the intermediate transfer unit 30 in which the toner container 4a is placed, viewed from the outside, in the vicinity of the connection frame 32, illustrating a state in which the intermediate transfer unit 30 is incompletely attached. [Figure 20] 20 is a front cross-sectional view of the vicinity of the protrusion 47 of the lock member 41 in FIG. 19. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic side view showing the internal configuration of an image forming apparatus 100 according to a first embodiment of the present invention. The image forming apparatus 100 shown in FIG. 1 is a so-called tandem type color printer, and has the following configuration. Four image forming sections Pa, Pb, Pc, and Pd are arranged in the main body of the image forming apparatus 100 in this order from the upstream side in the transport direction (the front side of the apparatus, the left side in FIG. 1). These image forming sections Pa to Pd are provided corresponding to images of four different colors (magenta, cyan, yellow, and black), and sequentially form images of magenta, cyan, yellow, and black through the respective processes of charging, exposure, development, and transfer.

[0014] These image forming stations Pa to Pd are provided with photoconductor drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of each color. Furthermore, an endless intermediate transfer belt 8 that rotates counterclockwise in FIG. 1 is provided adjacent to each image forming station Pa to Pd. The toner images formed on these photoconductor drums 1a to 1d are transferred sequentially onto the intermediate transfer belt 8 that moves while contacting each of the photoconductor drums 1a to 1d, and then transferred all at once onto a sheet S, which is an example of a recording medium, in a secondary transfer unit 9. Furthermore, after being fixed onto the sheet S in a fixing unit 13, the sheet S is discharged from the main body of the image forming apparatus 100. While the photoconductor drums 1a to 1d are rotated clockwise in FIG. 1, an image forming process is performed for each of the photoconductor drums 1a to 1d.

[0015] The paper S onto which the toner image is transferred is stored in a paper cassette 16 at the bottom of the main body of the image forming apparatus 100, and is transported to the secondary transfer roller 9 via a paper feed roller 12a and a pair of registration rollers 12b.

[0016] Next, the image forming units Pa to Pd will be described. Around the photosensitive drums 1a to 1d, charging devices 2a to 2d, developing devices 3a to 3d, and cleaning devices 7a to 7d are arranged in the drum rotation direction (clockwise direction in FIG. 1), and primary transfer rollers 6a to 6d are arranged with the intermediate transfer belt 8 in between. In addition, a belt cleaning unit 19 is arranged upstream of the image forming unit Pa with respect to the rotation direction of the intermediate transfer belt 8, facing the tension roller 11 with the intermediate transfer belt 8 in between. The belt cleaning unit 19 removes toner remaining on the surface of the intermediate transfer belt 8.

[0017] Next, an image forming procedure in the image forming apparatus 100 will be described. When a user inputs a command to start image formation, first, the photoconductor drums 1a-1d start to rotate by a main motor (not shown), and the surfaces of the photoconductor drums 1a-1d are uniformly charged by the charging devices 2a-2d. Next, the surfaces of the photoconductor drums 1a-1d are irradiated with a beam of light (laser light) emitted from an exposure device 5, and an electrostatic latent image corresponding to an image signal is formed on each of the photoconductor drums 1a-1d.

[0018] The developing devices 3a to 3d are filled with a predetermined amount of toner of each color, magenta, cyan, yellow, and black. When the ratio of toner in the two-component developer filled in each developing device 3a to 3d falls below a specified value due to the formation of a toner image described later, toner is replenished from the toner containers 4a to 4d to each developing device 3a to 3d. The toner in the developer is supplied onto the photoconductor drums 1a to 1d by the developing devices 3a to 3d and electrostatically adheres to them. As a result, a toner image is formed according to the electrostatic latent image formed by exposure from the exposure device 5.

[0019] Then, an electric field is applied between the primary transfer rollers 6a-6d and the photoconductor drums 1a-1d by the primary transfer rollers 6a-6d at a predetermined transfer voltage, and the magenta, cyan, yellow and black toner images on the photoconductor drums 1a-1d are primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship for forming a predetermined full-color image. Thereafter, in preparation for the subsequent formation of a new electrostatic latent image, the toner remaining on the surfaces of the photoconductor drums 1a-1d is removed by the cleaning devices 7a-7d.

[0020] When the intermediate transfer belt 8 starts to rotate counterclockwise with the rotation of the drive roller 10 by a belt drive motor (not shown), the paper S is transported from the registration roller pair 12b to a secondary transfer unit 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and a full-color image is transferred onto the paper S. The paper S onto which the toner image has been transferred is transported to a fixing unit 13. The toner remaining on the surface of the intermediate transfer belt 8 is removed by a belt cleaning unit 19.

[0021] The paper S conveyed to the fixing section 13 is heated and pressurized by the fixing roller pair 13a, so that the toner image is fixed to the surface of the paper S, and a predetermined full-color image is formed. The paper S on which the full-color image has been formed is then directed to a different conveying direction by the branching section 14, which branches into multiple directions, and is discharged directly (or after being sent to the double-sided conveying path 18 and printed on both sides) onto the discharge tray 17 by the discharge roller pair 15.

[0022] 2 is an external perspective view of the intermediate transfer unit 30 as viewed from the belt cleaning unit 19 side. As shown in FIG. 2, the intermediate transfer unit 30 has a pair of side frames 31a and 31b, a connecting frame 32, and an upper frame 33. The side frames 31a and 31b rotatably support a plurality of suspension rollers including the drive roller 10, the tension roller 11, and the primary transfer rollers 6a to 6d. Bushings (bearing members) 35 are attached to both ends of the rotation shaft of the drive roller 10. The bushes 35 fit into positioning portions 101a (see FIG. 11) of the main body frame 101 when the intermediate transfer unit 30 is attached to the image forming apparatus 100.

[0023] The connecting frame 32 is fixed to one end (the front left side in FIG. 2) of the side frames 31a and 31b in a bridging manner. A first handle portion 37 is provided on the upper portion of the connecting frame 32, and a pair of cover members 38 are attached to the left and right of the first handle portion 37.

[0024] The top frame 33 is fixed to the upper parts of the side frames 31a, 31a in a bridging manner. The top frame 33 is provided with container placement portions 33a to 33d on which the toner containers 4a to 4d (see FIG. 1) are placed, and a second handle portion 39.

[0025] Fig. 3 is a side view showing a state in which the cover member 38 has been removed from the connecting frame 32 of the intermediate transfer unit 30, and shows a state in which the intermediate transfer unit 30 is attached to the image forming apparatus 100. Fig. 4 is an external perspective view of the first handle portion 37 as seen from the rear side of Fig. 3, and Fig. 5 is a perspective view of a lock member 41 disposed inside the cover member 38. The lock mechanism 40 of the intermediate transfer unit 30 will be described in detail with reference to Figs. 3 to 5. In the following drawings, the removal direction of the intermediate transfer unit 30 on the connecting frame 32 side is indicated by arrow A, and the attachment direction is indicated by arrow A'.

[0026] 3, the connecting frame 32 is provided with a locking mechanism 40 that holds the intermediate transfer unit 30 in an attached state relative to the main body frame 101 (see FIG. 11) and is capable of releasing the hold. The locking mechanism 40 includes a first handle portion 37, a locking member 41, and a compression spring 43. The locking member 41 and the compression spring 43 are provided in pairs on the left and right sides of the first handle portion 37.

[0027] As shown in Fig. 4, the first handle portion 37 has a recess 37a, a protrusion 37b, and a guide rib 37c. The recess 37a is a recess into which a finger is inserted when attaching or detaching the intermediate transfer unit 30 to or from the image forming apparatus 100. The protrusion 37b and the guide rib 37c are formed as a pair on the left and right side surfaces of the first handle portion 37. The protrusion 37b protrudes from a lower portion of the first handle portion 37. The guide rib 37c extends in the up-down direction along the side surface of the first handle portion 37. The guide rib 37c engages with a rail groove (not shown) of the connecting frame 32, so that the first handle portion 37 is supported so as to be capable of reciprocating in the up-down direction relative to the connecting frame 32.

[0028] As shown in Fig. 5, the locking member 41 has a boss portion 41a, a hook portion 41b, an arm portion 41c, and a spring holding protrusion 41d. The boss portion 41a is rotatably fitted onto a support shaft 32a formed on the connecting frame 32. The hook portion 41b extends radially from the boss portion 41a and is engageable with an engaged portion 50 (see Fig. 3) on the main body frame 101 side. An inclined surface 45 inclined in the swing direction of the locking member 41 is formed on the outer side of the tip of the hook portion 41b.

[0029] The arm portion 41c extends from the boss portion 41a in a direction different from that of the hook portion 41b (a direction substantially perpendicular to the hook portion 41b) and contacts the protrusion 37b of the first handle portion 37. The spring holding projection 41d protrudes from the rear side of the hook portion 41b as a base end so as to have a smaller diameter toward the tip end.

[0030] One end of the compression spring 43 is fixed to the spring holding protrusion 41d of the locking member 41, and the other end is fixed to a spring fixing portion (not shown) of the connecting frame 32. The compression spring 43 biases the locking member 41 in a direction (first direction) in which the hook portion 41b engages with the engaged portion 50.

[0031] Next, the operation of releasing the lock mechanism 40 of the intermediate transfer unit 30 from the main body frame 101 will be described. Fig. 6 is an enlarged view of the lock mechanism 40 in Fig. 3, showing the state in which the lock member 41 and the engaged portion 50 are engaged. Fig. 7 is a side cross-sectional view (cross-sectional view taken along the arrow XX' in Fig. 3) of the vicinity of the connecting frame 32 of the intermediate transfer unit 30 in Fig. 3. Below, the lock mechanism 40 on the left side of the first handle portion 37 will be described, but the lock mechanism 40 on the right side of the first handle portion 37 will be described in exactly the same way except that it is symmetrical.

[0032] As shown in Fig. 6, when the intermediate transfer unit 30 is attached to the main body frame 101, the hook portion 41b of the locking member 41 engages with the engaged portion 50. The locking member 41 is biased by a compression spring 43 in a direction approaching the engaged portion 50 (a first direction, the clockwise direction in Fig. 6). This maintains the engaged state between the locking member 41 and the engaged portion 50, and prevents the intermediate transfer unit 30 from being removed.

[0033] Also, the arm portion 41c of the locking member 41 contacts the upper surface of the protruding portion 37b of the first handle portion 37 from above (from the upstream side in the mounting direction of the intermediate transfer unit 30). As a result, the urging force of the compression spring 43 acts on the protruding portion 37b via the locking member 41. Specifically, the first handle portion 37 is urged in the mounting direction of the intermediate transfer unit 30 (the direction of the arrow A') by the urging force of the compression spring 43.

[0034] Fig. 8 is a side view of the connecting frame 32 showing a state in which the first handle portion 37 has been pulled up from the state shown in Fig. 3. Fig. 9 is an enlarged view of the locking mechanism 40 shown in Fig. 8, showing a state in which the engagement between the locking member 41 and the engaged portion 50 has been released. Fig. 10 is a side cross-sectional view (cross-sectional view taken along the arrow XX' in Fig. 8) of the intermediate transfer unit 30 in Fig. 8 near the connecting frame 32.

[0035] When releasing the lock mechanism 40 of the intermediate transfer unit 30, the user inserts his or her fingers into the recess 37a of the first handle portion 37 to grip it, and pulls the first handle portion 37 upward (in the direction of the arrow A) against the biasing force of the compression spring 43, as shown in Fig. 10. As a result, as shown in Figs. 8 and 9, the protrusion 37b of the first handle portion 37 pushes up the arm portion 41c of the lock member 41, causing the lock member 41 to rotate in the counterclockwise direction.

[0036] As a result, the hook portion 41b compresses the compression spring 43 and swings in a direction away from the engaged portion 50 (the second direction, to the right in Figure 9), disengaging the hook portion 41b from the engaged portion 50 and making it possible to remove the intermediate transfer unit 30.

[0037] Fig. 11 is a side view showing a state in which the intermediate transfer unit 30 is attached to the main body frame 101. Fig. 12 is a side view showing a state immediately before the intermediate transfer unit 30 is removed from the main body frame 101.

[0038] When removing the intermediate transfer unit 30 from the main body frame 101, first, the opening / closing cover 17a constituting the discharge tray 17 (see FIG. 1) is opened, and the toner containers 4a to 4d (see FIG. 1) are removed to obtain the state shown in FIG. 11. Next, with the first handle portion 37 pulled up as shown in FIG. 10, the end portion of the intermediate transfer unit 30 on the device front side (left side in FIG. 11) is lifted upward (removal direction, arrow A direction). Then, when it is lifted up to a predetermined angle shown in FIG. 12, the second handle portion 39 is grasped together with the first handle portion 37, and the end portion (bush 35) on the device rear side (right side in FIG. 12) of the intermediate transfer unit 30 is pulled out from the positioning portion 101a and pulled out to the device front side, completing the removal of the intermediate transfer unit 30.

[0039] When mounting the intermediate transfer unit 30 to the main body frame 101, first, with the front side of the intermediate transfer unit 30 raised as shown in Fig. 12, the end portion (bush 35) on the rear side of the device is fitted into the positioning portion 101a. Then, the front side of the intermediate transfer unit 30 is gradually lowered downward (mounting direction, arrow A' direction).

[0040] When the front side of the intermediate transfer unit 30 is lowered to a predetermined position, the inclined surface 45 formed on the hook portion 41b of the locking member 41 abuts against the engaged portion 50 on the main body frame 101 side, as shown in FIG.

[0041] 13, when the front side of the intermediate transfer unit 30 is further lowered, the inclined surface 45 receives a resistance from the engaged portion 50 due to a reaction. Since the locking member 41 is supported so as to be able to swing about the boss portion 41a as a fulcrum, the hook portion 41b swings in a direction (second direction, rightward in FIG. 13) away from the engaged portion 50 against the biasing force of the compression spring 43 due to a horizontal (rightward in FIG. 13) component of the resistance received from the engaged portion 50.

[0042] Thereafter, when the locking member 41 swings in the second direction until the inclined surface 45 is released from the engaged portion 50, the tip of the hook portion 41b descends along the right side surface of the engaged portion 50. Then, when the tip of the hook portion 41b overcomes the lower end of the engaged portion 50, the action of the resistance force from the engaged portion 50 disappears, and the locking member 41 swings in a direction approaching the engaged portion 50 (the first direction, the left direction in FIG. 13) due to the biasing force of the compression spring 43. As a result, the hook portion 41b and the engaged portion 50 engage with each other as shown in FIG. 3 and FIG. 6, and removal of the intermediate transfer unit 30 is restricted. In this manner, the attachment of the intermediate transfer unit 30 to the main body frame 101 is completed.

[0043] According to the above configuration, when removing the intermediate transfer unit 30 from the image forming apparatus 100, the locking member 41 can be released from the engagement portion 50 simply by grasping and pulling up the first handle portion 37. Furthermore, since the operation direction of the first handle portion 37 for releasing the locking mechanism 40 and the removal direction of the intermediate transfer unit 30 are the same (upward), the release of the locking mechanism 40 and the removal operation of the intermediate transfer unit 30 can be performed simultaneously. Therefore, the user can release the locking mechanism 40 of the intermediate transfer unit 30 with a simple operation without tightening screws or operating a rotary lever, and the replacement work of the intermediate transfer unit 30 can be performed smoothly.

[0044] Furthermore, when the intermediate transfer unit 30 is attached to the image forming apparatus 100, the hook portion 41b of the locking member 41 engages with the engaged portion 50 of the main body frame 101 simply by inserting the intermediate transfer unit 30. Therefore, the intermediate transfer unit 30 can be automatically locked to the main body frame 101 by using the locking mechanism 40 without any special operation.

[0045] Next, a second embodiment of the present invention will be described. In the above-described first embodiment, it was not possible to recognize a state in which the intermediate transfer unit 30 was incompletely attached to the main body frame 101. As a result, an image forming operation may be performed with the intermediate transfer unit 30 in an incompletely attached state, which may result in poor transfer or damage to the intermediate transfer unit 30. Therefore, the image forming apparatus 100 of the second embodiment is provided with a mechanism for recognizing whether the intermediate transfer unit 30 is properly attached to the main body frame 101 or not.

[0046] 14 is a perspective view of a locking member 41 disposed inside the cover member 38 in an image forming apparatus 100 according to the second embodiment. The locking member 41 has a protrusion 47 that protrudes from a side surface of the hook portion 41b along the extension direction of the boss portion 41a (the axial direction of the support shaft 32a) toward the inside of the intermediate transfer unit 30 (the right side in FIG. 15). The configuration of other parts of the locking member 41 is similar to that of the first embodiment shown in FIG.

[0047] Fig. 15 is a side view of the vicinity of the connecting frame 32 of the intermediate transfer unit 30, showing a state in which the toner container 4a is placed on the container placement portion 33a. Fig. 16 is a perspective view of the appearance of the toner container 4a. A leg portion 60 is formed on the bottom of the toner container 4a at a position adjacent to the protrusion 47 of the locking member 41.

[0048] Fig. 17 is a front view of the vicinity of the connecting frame 32 of the intermediate transfer unit 30 on which the toner container 4a is placed, as viewed from the outside, and shows a state in which the intermediate transfer unit 30 is normally attached. Fig. 18 is a front cross-sectional view (cross-sectional view taken along the YY' arrow in Fig. 15) of the vicinity of the protrusion 47 of the lock member 41 in Fig. 17.

[0049] When the intermediate transfer unit 30 is properly attached to the main body frame 101, the hook portion 41b of the locking member 41 is fully engaged with the engaged portion 50 as shown in Fig. 17. At this time, the protrusion 47 of the locking member 41 is retracted to a position where it does not contact the leg portion 60 of the toner container 4a as shown in Fig. 18. As a result, the toner container 4a is placed horizontally on the container placement portion 33a formed on the upper frame 33 of the intermediate transfer unit 30.

[0050] Fig. 19 is a front view of the connecting frame 32 of the intermediate transfer unit 30 on which the toner container 4a is placed, viewed from the outside, and shows a state in which the intermediate transfer unit 30 is incompletely attached. Fig. 20 is a front cross-sectional view (cross-sectional view taken along the YY' arrow in Fig. 15) of the protrusion 47 of the lock member 41 in Fig. 19 and its vicinity.

[0051] When the intermediate transfer unit 30 is incompletely attached to the main body frame 101, the hook portion 41b of the locking member 41 is not completely engaged with the engaged portion 50 as shown in Fig. 19. More specifically, the locking member 41 swings in a direction away from the engaged portion 50 (a second direction, horizontally inward in Fig. 19) due to a resistance from the engaged portion 50.

[0052] At this time, as shown in Fig. 20, the protrusion 47 of the locking member 41 is also positioned at a position swung inward compared to Fig. 18. As a result, when the toner container 4a is placed on the container placement portion 33a, the legs 60 interfere with (contact with) the protrusion 47, and the toner container 4a is placed in an inclined state. Therefore, after the intermediate transfer unit 30 is attached to the main body frame 101, it can be recognized whether the intermediate transfer unit 30 is normally attached or not depending on whether the toner container 4a is placed horizontally or not.

[0053] 19 and 20, the intermediate transfer unit 30 is also pushed down together with the toner container 4a, so that the tip of the hook portion 41b descends along the side of the engaged portion 50. Then, when the tip of the hook portion 41b overcomes the lower end of the engaged portion 50, the action of the resistance force from the engaged portion 50 disappears, and the lock member 41 enters the state shown in FIGS. 17 and 18 in which it is completely engaged with the engaged portion 50 by the biasing force of the compression spring 43.

[0054] Therefore, both the intermediate transfer unit 30 and the toner container 4a are properly attached simply by pushing down the toner container 4a, and there is no need to remove the intermediate transfer unit 30 from the main body frame 101 and then reinstall it, improving the ease of attachment.

[0055] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention. For example, in the above-described embodiments, the intermediate transfer unit 30 is mounted and removed by lifting one end up and down from the other end of the intermediate transfer unit 30, but the intermediate transfer unit 30 may be inserted and removed horizontally from the main body of the image forming apparatus 100. In addition, the present invention may be applied to units other than the intermediate transfer unit 30 as long as the units are detachable from the main body of the image forming apparatus 100.

[0056] In addition, in the above embodiment, when the intermediate transfer unit 30 is inserted into the main body frame 101, the locking member 41 is swung using the inclined surface 45 formed on the hook portion 41b of the locking member 41, but the inclined surface 45 can also be formed on the engaged portion 50 side.

[0057] Furthermore, the present invention is not limited to a tandem type color printer as in the above embodiment, but can be applied to various image forming apparatuses equipped with units that can be attached or detached to the image forming apparatus 100 main body, such as monochrome copiers, digital multifunction machines, facsimiles, and laser printers. [Industrial Applicability]

[0058] The present invention can be used in an image forming apparatus having a unit that is detachable from the main body of the apparatus. By using the present invention, it is possible to provide an image forming apparatus that can lock and unlock a unit that is detachable from the main body of the apparatus with a simple configuration. [Explanation of symbols]

[0059] 4a Toner container (second unit) 6a to 6d Primary transfer rollers (suspension rollers) 8 Intermediate transfer belt 10 Driving roller (suspension roller) 11 Tension roller (suspension roller) 30 Intermediate transfer unit (first unit) 31a, 31b Side frame 32 Connecting Frame 32a spindle 33 Top Frame 37 First handle (handle) 37a Recess 37b Protrusion 39 Second Handle Section 40 Locking mechanism 41 Locking member 41a Boss part 41b Hook part 41c Arm section 43 Compression spring (biasing member) 45 Slope 47 Convex 50 Engaged part 60 Legs 100 Image forming device 101 Main frame

Claims

1. a first unit detachable from a main body frame; a lock mechanism that holds the first unit in a mounted state on the main body frame and is capable of releasing the held state; Equipped with The locking mechanism includes: a handle portion disposed on the first unit and reciprocally movable in a mounting direction and a removal direction of the first unit; a locking member that is swingably disposed on the first unit and has a hook portion that can be engaged with an engaged portion formed on the main body frame; a biasing member that biases the locking member in a first direction in which the hook portion engages with the engaged portion, By moving the handle portion in the removal direction, the locking member swings in a second direction opposite to the first direction against the biasing force of the biasing member, and the engagement between the hook portion and the engaged portion is released, making it possible to remove the first unit from the main body frame. The handle portion has a pair of protruding portions protruding from left and right side surfaces, a pair of the locking members are arranged on the left and right of the handle portion, and each of the locking members has a boss portion rotatably engaged with a support shaft formed in the first unit, the hook portion extending radially from the boss portion, and an arm portion extending from the boss portion in a direction different from that of the hook portion and contacting the protruding portion from the upstream side in the mounting direction, When the first unit is attached to the main body frame, the handle portion is biased in the attachment direction by the biasing member via the locking member, By moving the handle portion in the removal direction, the protrusion presses the arm portion in the removal direction against the biasing force of the biasing member, causing the locking member to swing in the second direction, and the engagement between the hook portion and the engaged portion is released. the locking member pivots about the support shaft perpendicular to the mounting direction and the removal direction in the first direction away from the handle portion and in the second direction toward the handle portion.

2. 2. The image forming apparatus according to claim 1, wherein when the first unit is attached to the main frame, the locking member swings in the second direction against the biasing force of the biasing member due to a resistance force received by the locking member from the engaged portion, and when the first unit is attached to a predetermined position, the locking member moves in the first direction due to the biasing force of the biasing member, and the hook portion engages with the engaged portion.

3. 3. The image forming apparatus according to claim 2, wherein at least one of the hook portion and the engaged portion has an inclined surface that is inclined in the pivoting direction of the locking member at a portion that abuts the engaged portion or the hook portion when the first unit is attached to the main frame.

4. A second unit attached to an upper portion of the first unit, 4. An image forming apparatus according to claim 1, wherein the locking member has a convex portion that allows the second unit to be attached when the hook portion and the engaged portion are engaged, and that restricts the attachment of the second unit when the hook portion and the engaged portion are disengaged.

5. The handle portion has a pair of protrusions protruding from the left and right side surfaces, the locking members are arranged in pair on the left and right of the handle portion, and have a boss portion rotatably engaged with a support shaft formed in the first unit, the hook portion extending radially from the boss portion, and an arm portion extending from the boss portion in a direction different from that of the hook portion and contacting the protrusion from the upstream side in the mounting direction, the protrusion extends from a side surface of the hook portion along an axial direction of the support shaft to a lower portion of the second unit, 5. The image forming apparatus according to claim 4, characterized in that when the engagement between the hook portion and the engaged portion is released, the convex portion is positioned in a position where it contacts a leg formed on a bottom surface of the second unit, and when the hook portion and the engaged portion engage, the convex portion retracts to a position where it does not contact the leg.

6. An image forming apparatus as described in claim 4 or claim 5, characterized in that the first unit is attached to a predetermined position by pushing down the second unit, and the locking member swings in the first direction due to the biasing force of the biasing member, causing the hook portion to engage with the engaged portion.

7. An image forming apparatus as described in any one of claims 4 to 6, characterized in that the second unit is a toner container that stores toner for forming an image on a recording medium.

8. A first unit that is detachable from a main body frame; a lock mechanism that holds the first unit in a mounted state on the main body frame and is capable of releasing the held state; Equipped with The locking mechanism includes: a handle portion disposed on the first unit and reciprocally movable in a mounting direction and a removal direction of the first unit; a locking member that is swingably disposed on the first unit and has a hook portion that can be engaged with an engaged portion formed on the main body frame; a biasing member that biases the locking member in a first direction in which the hook portion engages with the engaged portion, By moving the handle portion in the removal direction, the locking member swings in a second direction opposite to the first direction against the biasing force of the biasing member, and the engagement between the hook portion and the engaged portion is released, making it possible to remove the first unit from the main body frame. A second unit is attached to an upper portion of the first unit, an image forming apparatus characterized in that the locking member allows the second unit to be attached when the hook portion and the engaged portion are engaged, and has a convex portion that restricts the attachment of the second unit when the hook portion and the engaged portion are disengaged.

9. The handle portion has a pair of protrusions protruding from the left and right side surfaces, the locking members are arranged in pair on the left and right of the handle portion, and have a boss portion rotatably engaged with a support shaft formed in the first unit, the hook portion extending radially from the boss portion, and an arm portion extending from the boss portion in a direction different from that of the hook portion and contacting the protrusion from the upstream side in the mounting direction, the protrusion extends from a side surface of the hook portion along an axial direction of the support shaft to a lower portion of the second unit, 9. The image forming apparatus according to claim 8, characterized in that when the engagement between the hook portion and the engaged portion is released, the convex portion is positioned in a position in contact with a leg formed on a bottom surface of the second unit, and when the hook portion and the engaged portion engage, the convex portion retracts to a position where it does not contact the leg.

10. An image forming apparatus as described in claim 7 or claim 8, characterized in that when the first unit is attached to the main body frame, the locking member swings in the second direction against the biasing force of the biasing member due to the resistance that the locking member receives from the engaged portion, and when the first unit is attached to a predetermined position, the locking member moves in the first direction due to the biasing force of the biasing member, and the hook portion engages with the engaged portion.

11. An image forming device as described in Claim 10, characterized in that at least one of the hook portion or the engaged portion has an inclined surface that is inclined in the swinging direction of the locking member at the portion that abuts the engaged portion or the hook portion when the first unit is attached to the main body frame.

12. An image forming apparatus as described in claim 10 or claim 11, characterized in that the first unit is attached to a predetermined position by pushing down the second unit, and the locking member swings in the first direction due to the biasing force of the biasing member, causing the hook portion to engage with the engaged portion.

13. The image forming apparatus according to claim 10, wherein the second unit is a toner container that stores toner for forming an image on a recording medium.

14. A first unit that is detachable from a main body frame; a lock mechanism that holds the first unit in a mounted state on the main body frame and is capable of releasing the held state; Equipped with The locking mechanism includes: a handle portion disposed on the first unit and reciprocally movable in a mounting direction and a removal direction of the first unit; a locking member that is swingably disposed on the first unit and has a hook portion that can be engaged with an engaged portion formed on the main body frame; a biasing member that biases the locking member in a first direction in which the hook portion engages with the engaged portion, By moving the handle portion in the removal direction, the locking member swings in a second direction opposite to the first direction against the biasing force of the biasing member, and the engagement between the hook portion and the engaged portion is released, making it possible to remove the first unit from the main body frame. The image forming apparatus is characterized in that the first unit is an intermediate transfer unit having an endless intermediate transfer belt on which toner images to be transferred to a recording medium are sequentially stacked, and a plurality of suspension rollers that suspend the intermediate transfer belt.

15. The intermediate transfer unit has a pair of side frames supporting both axial ends of the suspension roller, and a connecting frame connected to one end of the side frames in a bridging manner, and is detachable by raising and lowering the connecting frame side relative to the main frame, 15. The image forming apparatus according to claim 14, wherein the lock mechanism is provided on the connecting frame.

16. An image forming apparatus as described in claim 14 or claim 15, characterized in that when the first unit is attached to the main body frame, the locking member swings in the second direction against the biasing force of the biasing member due to the resistance that the locking member receives from the engaged portion, and when the first unit is attached to a predetermined position, the locking member moves in the first direction due to the biasing force of the biasing member, and the hook portion engages with the engaged portion.

17. An image forming device as described in Claim 16, characterized in that at least one of the hook portion or the engaged portion has an inclined surface that is inclined in the swinging direction of the locking member at the portion that abuts the engaged portion or the hook portion when the first unit is attached to the main body frame.

18. A second unit attached to an upper portion of the first unit, 18. An image forming apparatus according to claim 14, wherein the locking member has a convex portion that allows the second unit to be attached when the hook portion and the engaged portion are engaged with each other, and that restricts the attachment of the second unit when the hook portion and the engaged portion are disengaged from each other.

19. The handle portion has a pair of protrusions protruding from the left and right side surfaces, the locking members are arranged in pair on the left and right of the handle portion, and have a boss portion rotatably engaged with a support shaft formed in the first unit, the hook portion extending radially from the boss portion, and an arm portion extending from the boss portion in a direction different from that of the hook portion and contacting the protrusion from the upstream side in the mounting direction, the protrusion extends from a side surface of the hook portion along an axial direction of the support shaft to a lower portion of the second unit, 19. The image forming apparatus according to claim 18, wherein when the engagement between the hook portion and the engaged portion is released, the convex portion is positioned in a position where it contacts a leg formed on a bottom surface of the second unit, and when the hook portion and the engaged portion engage, the convex portion retracts to a position where it does not contact the leg.

20. An image forming apparatus as described in claim 18 or claim 19, characterized in that the first unit is attached to a predetermined position by pushing down the second unit, and the locking member swings in the first direction due to the biasing force of the biasing member, causing the hook portion to engage with the engaged portion.

21. The image forming apparatus according to claim 18, wherein the second unit is a toner container that stores toner for forming an image on a recording medium.

Images