Image forming apparatus

Abstract

To achieve, with a simple configuration, an electric shock prevention mechanism for a transfer voltage output terminal when a transfer member is supported on a movable unit.SOLUTION: A transfer member 433 is supported on a movable unit 6. A blocking member 73 is movable between a blocking position where it blocks an access path to a first terminal 71 and an opening position where it opens the access path. A second terminal 72 is supported on the movable unit 6. A locking mechanism 70, in conjunction with the movement of the movable unit 6, locks the blocking member 73 at the blocking position when the movable unit 6 is located at a separation position, and releases the lock of the blocking member 73 when the movable unit 6 moves from the separation position to a reference position. When the movable unit 6 moves from the separation position to the reference position, the second terminal 72 moves to a position where it is in contact with the first terminal 71 via the access path.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus having a movable unit that supports a transfer member to which a transfer voltage is applied. [Background technology]

[0002] In an electrophotographic image forming apparatus, a transfer device transfers a toner image from an image carrier bearing the toner image to a sheet. The transfer device includes a transfer member to which a transfer voltage is applied. The transfer member transfers the toner image from the image carrier to the sheet by an electric field generated by the transfer voltage.

[0003] In the image forming device, a mechanism is known that brings two terminals arranged in the main body into contact with and separates them depending on the attachment and detachment of a process unit to and from the main body of the image forming device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-77921 Summary of the Invention [Problem to be solved by the invention]

[0005] In some cases, the transfer member is supported by a movable unit that can be moved toward or away from the image carrier, and when the movable unit is moved to a position away from the image carrier, the sheet transport path between the image carrier and the transfer member is opened.

[0006] It is important to provide an electric shock prevention mechanism that prevents a user from touching the output terminal of the transfer voltage when the movable unit is separated from the image carrier, and it is desirable that the electric shock prevention mechanism be realized with a simple configuration.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can realize an electric shock prevention mechanism for the output terminal of the transfer voltage with a simple configuration when the transfer member is supported by a movable unit. [Means for solving the problem]

[0008] According to one aspect of the present invention, an image forming apparatus includes an image carrier, a first terminal, a movable unit, a second terminal, a transfer member, a blocking member, and a locking mechanism. The image carrier carries a developer image. The first terminal outputs a transfer voltage. The movable unit is supported movably between a reference position close to the image carrier and the first terminal and a remote position farther from the image carrier and the first terminal than the reference position. The second terminal is supported by the movable unit and contacts the first terminal when the movable unit is located at the reference position and separates from the first terminal when the movable unit is located at the remote position. The transfer member is supported by the movable unit and electrically connected to the second terminal. When the movable unit is located at the reference position, the transfer member transfers the developer image carried on the image carrier to a sheet passing between the image carrier and the movable unit. The blocking member is movable between a blocking position that blocks an access path to the first terminal and an open position that opens the access path. The locking mechanism is linked to movement of the movable unit, locking the blocking member at the blocking position when the movable unit is located at the separated position, and unlocking the blocking member when the movable unit moves from the separated position to the reference position. When the movable unit moves from the separated position to the reference position, the second terminal moves to a position in contact with the first terminal via the access path, while moving the blocking member, which has been released from the locking mechanism by the locking mechanism, from the blocking position to the open position. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an image forming apparatus that can realize an electric shock prevention mechanism for the output terminal of the transfer voltage with a simple configuration when the transfer member is supported by a movable unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the electric shock prevention mechanism in the connected state in the image forming apparatus according to the embodiment. [Figure 3] FIG. 3 is a perspective view of the electric shock prevention mechanism in the open state in the image forming apparatus according to the embodiment. [Figure 4] FIG. 4 is a side view including a partial cross section of the electric shock prevention mechanism in the connected state in the image forming apparatus according to the embodiment. [Figure 5] FIG. 5 is a first surface view of the electric shock prevention mechanism in the connected state in the image forming apparatus according to the embodiment. [Figure 6] FIG. 6 is a second view of the electric shock prevention mechanism in the connected state in the image forming apparatus according to the embodiment. [Figure 7] FIG. 7 is a side view including a partial cross section of the electric shock prevention mechanism in the intermediate state in the image forming apparatus according to the embodiment. [Figure 8] FIG. 8 is a first view of the electric shock prevention mechanism in the intermediate state in the image forming apparatus according to the embodiment. [Figure 9] FIG. 9 is a second view of the electric shock prevention mechanism in the intermediate state in the image forming apparatus according to the embodiment. [Figure 10] FIG. 10 is a side view including a partial cross section of the electric shock prevention mechanism in the open state in the image forming apparatus according to the embodiment. [Figure 11] FIG. 11 is a first view of the electric shock prevention mechanism in the open state in the image forming apparatus according to the embodiment. [Figure 12] FIG. 12 is a second view of the electric shock prevention mechanism in the open state in the image forming apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention.

[0012] [Configuration of image forming apparatus 10] The image forming apparatus 10 according to the embodiment includes a printing device 4 that performs a printing process using an electrophotographic method. The printing process is a process of forming an image on a sheet 9. The sheet 9 is an image forming medium such as paper or a sheet-like resin member.

[0013] 1, an image forming apparatus 10 includes a sheet conveying device 3 and a printing device 4 disposed within a main body 1. The main body 1 is a housing that houses the sheet conveying device 3, the printing device 4, and the like.

[0014] The printing device 4 includes one or more image forming units 4x, an optical scanning device 40, a transfer device 44, and a fixing device 46. The image forming unit 4x includes a drum-shaped photosensitive member 41, a charging device 42, a developing device 43, a drum cleaning device 45, and the like.

[0015] The sheet conveying device 3 includes a sheet sending device 31 and a plurality of pairs of conveying rollers 32. The sheet conveying device 3 further includes a drive device (not shown) that drives the sheet sending device 31 and the plurality of pairs of conveying rollers 32.

[0016] The sheet feeding device 31 feeds the sheets 9 stored in the sheet storage unit 2 to a sheet transport path 30 in the main body 1. The sheet transport path 30 forms a passage along which the sheets 9 are transported.

[0017] The plurality of conveying roller pairs 32 are rotationally driven by the drive device. The plurality of conveying roller pairs 32 convey the sheet 9 along the sheet conveying path 30 by rotating with the sheet 9 sandwiched between them.

[0018] The sheet transport path 30 includes a main transport path 301 and a sub-transport path 302. The main transport path 301 is a path that extends from the entrance 30a to the discharge port 30b via the registration position P1, the transfer position P2, and the fixing position P3.

[0019] In this embodiment, the transfer position P2 is located above the registration position P1, and the fixing position P3 is located above the transfer position P2. The registration position P1 is located above the inlet 30a, and the outlet 30b is located above the fixing position P3.

[0020] The sub-transport path 302 branches off from the main transport path 301 at a portion between the fixing position P3 and the discharge port 30b, and merges with the main transport path 301 at a portion between the carry-in port 30a and the registration position P1.

[0021] The plurality of pairs of conveying rollers 32 include a pair of registration rollers 32a and a pair of discharge rollers 32b.

[0022] The pair of registration rollers 32a temporarily stops the sheet 9 at the registration position P1 and then sends the sheet 9 to the transfer position P2. The timing at which the sheet 9 is sent to the transfer position P2 is adjusted by the action of the pair of registration rollers 32a.

[0023] The discharge roller pair 32b rotates in the first rotation direction to discharge the sheet 9 that has passed through the fixing position P3 onto the discharge tray 101 from the discharge opening 30b of the main transport path 301.

[0024] The sheet conveying device 3 further includes a path switching mechanism 35. The path switching mechanism 35 is selectively switched between a first state and a second state.

[0025] When in the first state, the path switching mechanism 35 opens a path from the fixing position P3 on the main transport path 301 to the discharge port 30b. When in the second state, the path switching mechanism 35 opens a path from the discharge port 30b on the main transport path 301 to the sub-transport path 302.

[0026] When the path switching mechanism 35 is in the first state, the discharge roller pair 32b is driven to rotate in the first rotation direction. When the path switching mechanism 35 is in the first state, the discharge roller pair 32b rotates in the second rotation direction to reverse and transport the sheet 9. As a result, the sheet 9 is transported into the sub-transport path 302.

[0027] Some of the plurality of pairs of transport rollers 32 transport the sheet 9 along the sub-transport path 302, and then send the sheet 9 out again to the registration position P1 on the main transport path 301.

[0028] The printing device 4 forms a toner image on the sheet 9 transported along the main transport path 301 by the sheet transport device 3. The toner image is a developer image using toner as a developer. The toner is an example of the granular developer.

[0029] 1 is a tandem color image forming apparatus. Therefore, the printing device 4 has multiple image forming units 4x corresponding to the multiple colors of toner. In this embodiment, the printing device 4 has four image forming units 4x corresponding to the four colors of yellow, cyan, magenta, and black.

[0030] In each image forming unit 4x, a photoconductor 41 rotates, and a charging device 42 charges the surface of the photoconductor 41. Furthermore, an optical scanning device 40 writes an electrostatic latent image on the surface of the photoconductor 41 by scanning with a laser beam.

[0031] Furthermore, the developing device 43 supplies the toner to the surface of the photoreceptor 41, thereby developing the electrostatic latent image into the toner image.

[0032] The transfer device 44 transfers the toner image onto the sheet 9 at a transfer position P2 on the sheet transport path 30. The transfer device 44 includes an intermediate transfer belt 441, four primary transfer rollers 442 corresponding to the four image forming units 4x, a secondary transfer roller 443, and a belt cleaning device 444.

[0033] Furthermore, the transfer device 44 includes a voltage output device 440 that supplies a transfer voltage to the four primary transfer rollers 442 and the secondary transfer roller 443 .

[0034] Each primary transfer roller 442 rotates following the rotation of each photoconductor 41. Each secondary transfer roller 443 rotates following the rotation of the intermediate transfer belt 441.

[0035] In the transfer device 44, the primary transfer roller 442 transfers the toner image on the surface of the photosensitive member 41 onto the surface of the intermediate transfer belt 441. As a result, the color toner image is formed on the surface of the intermediate transfer belt 441.

[0036] The primary transfer roller 442 transfers the toner image from the surface of the photoreceptor 41 to the surface of the intermediate transfer belt 441 by an electric field generated by the transfer voltage.

[0037] The secondary transfer roller 443 transfers the toner image formed on the intermediate transfer belt 441 onto the sheet 9 at the transfer position P2 on the main transport path 301. That is, the secondary transfer roller 443 transfers the toner image carried on the intermediate transfer belt 441 onto the sheet 9 passing between the intermediate transfer belt 441 and the secondary transfer roller 443.

[0038] The secondary transfer roller 443 transfers the toner image from the surface of the intermediate transfer belt 441 to the surface of the sheet 9 by the electric field generated by the transfer voltage.

[0039] The photoreceptor 41 and the intermediate transfer belt 441 are examples of image carriers that rotate while carrying the toner image. The secondary transfer roller 443 is an example of a transfer member that transfers the toner image carried on the intermediate transfer belt 441 onto the sheet 9.

[0040] When the image forming apparatus 10 is a monochrome image forming apparatus, the secondary transfer roller 443 transfers the toner image on the photoreceptor 41 onto the sheet 9 at the transfer position P2.

[0041] The drum cleaning device 45 removes the waste toner remaining on the surface of the photosensitive member 41. The belt cleaning device 444 removes the waste toner remaining on the intermediate transfer belt 441.

[0042] The fixing device 46 heats and presses the toner image on the sheet 9 while transporting the sheet 9 at a fixing position P3 on the main transport path 301. In this way, the fixing device 46 fixes the toner image on the sheet 9.

[0043] Incidentally, there is a case where the secondary transfer roller 443 is supported by a movable unit 6 that is capable of moving toward and away from the intermediate transfer belt 441. When the movable unit 6 is moved to a position away from the intermediate transfer belt 441, the sheet conveying path between the intermediate transfer belt 441 and the secondary transfer roller 443 is opened.

[0044] It is important to provide an electric shock prevention mechanism 7 that prevents the user from touching the output terminal of the transfer voltage when the movable unit 6 is separated from the intermediate transfer belt 441. It is also desirable that the electric shock prevention mechanism 7 be realized with a simple configuration.

[0045] The image forming apparatus 10 includes an outer cover 5 that closes an opening formed in the main body 1, a movable unit 6 provided inside the outer cover 5, and an electric shock prevention mechanism 7. The secondary transfer roller 443 is rotatably supported by the movable unit 6.

[0046] In the following description, the direction from the outer cover 5 or the movable unit 6 toward the outside of the main body 1 is referred to as the outward direction D11. The direction opposite to the outward direction D11 is referred to as the inward direction D12. The direction along the outward direction D11 and the inward direction D12 is referred to as the depth direction D1.

[0047] In each drawing, the width direction D2 is a horizontal direction that intersects with the depth direction D1, and the vertical direction D3 is a direction that intersects with the depth direction D1 and the width direction D2. The vertical direction D3 is the up-down direction.

[0048] 4, 5, 7, 8, 10, and 11 are views of the electric shock prevention mechanism 7 as viewed along the width direction D2. Figures 6, 9, and 12 are views of the electric shock prevention mechanism 7 as viewed from inside in the depth direction D1.

[0049] The four photoconductors 41, the four primary transfer rollers 442, and the secondary transfer roller 443 each rotate about a rotation axis along the width direction D2.

[0050] The outer cover 5 is rotatably supported by the main body 1. The outer cover 5 is rotatable about a first support shaft 5x supported by the main body 1. The outer cover 5 is rotatable in an outward direction D11 from a closed position where it covers the movable unit 6.

[0051] The outer cover 5 is movable between the closed position and an open position that exposes the movable unit 6. In Fig. 1, the outer cover 5 positioned at the closed position is shown by a solid line, and the outer cover 5 positioned at the open position is shown by a two-dot chain line.

[0052] The movable unit 6 rotatably supports the secondary transfer roller 443. The movable unit 6 is supported so as to be rotatable about a second support shaft 6x supported by the main body 1.

[0053] The electric shock prevention mechanism 7 includes a first terminal 71, a second terminal 72, a blocking member 73, and a locking mechanism 70 (see FIGS. 2 and 3). The first terminal 71 and the second terminal 72 are each a conductive member. In this embodiment, the first terminal 71 and the second terminal 72 are metal members.

[0054] The first terminal 71 is electrically connected to the voltage output device 440 and outputs the transfer voltage. The movable unit 6 is supported by the second support shaft 6x so as to be movable between a reference position and a separated position.

[0055] In Fig. 1, the movable unit 6 located at the reference position is indicated by a solid line, and the movable unit 6 located at the remote position is indicated by a two-dot chain line. The movable unit 6 shown in Fig. 2 is located at the reference position. The movable unit 6 shown in Fig. 3 is located at the remote position.

[0056] The intermediate transfer belt 441 is rotatably supported at a predetermined position within the main body 1. The first terminal 71 is fixed at a predetermined position within the main body 1.

[0057] The reference position is a position close to the intermediate transfer belt 441 and the first terminal 71. The remote position is a position farther from the intermediate transfer belt 441 and the first terminal 71 than the reference position.

[0058] When the outer cover 5 is in the open position, the movable unit 6 is movable between the reference position and the separated position.

[0059] The sheet transport device 3 includes a first main transport guide 33, a second main transport guide 61, a first sub transport guide 62, and a second sub transport guide 51, each of which guides the transport of a sheet 9 (see FIG. 1).

[0060] The first main transport guide 33 is disposed next to the intermediate transfer belt 441. The second main transport guide 61 and the first sub transport guide 62 are supported by the movable unit 6. The second sub transport guide 51 is supported by the outer cover 5.

[0061] When the movable unit 6 is located at the reference position, the second main transport guide 61 forms a part of the main transport path 301 between itself and the first main transport guide 33. When the movable unit 6 is located at the separated position, the second main transport guide 61 moves away from the first main transport guide 33, thereby opening a part of the main transport path 301.

[0062] The first main transport guide 33 and the second main transport guide 61 are examples of a first transport guide and a second transport guide, respectively.

[0063] When the movable unit 6 is located at the reference position and the outer cover 5 is located at the closed position, the second auxiliary transport guide 51 forms a part of the auxiliary transport path 302 between itself and the first auxiliary transport guide 62. When the outer cover 5 is located at the open position, the auxiliary transport path 302 is opened.

[0064] The electric shock prevention mechanism 7 is a mechanism that prevents electric shock caused by contact with the first terminal 71 when the movable unit 6 is located at the separated position. The first terminal 71 is an output terminal for the transfer voltage.

[0065] The second terminal 72 is supported by the movable unit 6. When the movable unit 6 is located at the reference position, the second terminal 72 contacts the first terminal 71 (see FIGS. 2 and 5). On the other hand, when the movable unit 6 is located at the separated position, the second terminal 72 is separated from the first terminal 71 (see FIGS. 3 and 11).

[0066] The secondary transfer roller 443 is electrically connected to the second terminal 72. When the movable unit 6 is located at the reference position, the secondary transfer roller 443 transfers the toner image onto the sheet 9 passing between the secondary transfer roller 443 and the intermediate transfer belt 441.

[0067] The blocking member 73 is movable between a blocking position where it blocks the access path to the first terminal 71 and an open position where it opens the access path. Figures 3, 11, and 12 show the blocking member 73 in the blocking position. Figures 2, 5, and 6 show the blocking member 73 in the open position.

[0068] Specifically, blocking member 73 is rotatably supported by a third support shaft 73x disposed at a predetermined position within main body 1. The blocking position is the position of blocking member 73 when blocking member 73 hangs downward from third support shaft 73x (see FIGS. 3, 11, and 12). On the other hand, the open position is the position of blocking member 73 when blocking member 73 is lifted upward in inward direction D12 relative to the blocking position (see FIGS. 2, 5, and 6).

[0069] The locking mechanism 70 is a mechanism that operates in conjunction with the movement of the movable unit 6. When the movable unit 6 is located at the separated position, the locking mechanism 70 locks the blocking member 73 at the separated position (see FIG. 11). On the other hand, the locking mechanism 70 releases the lock on the blocking member 73 when the movable unit 6 moves from the separated position to the reference position (see FIG. 5).

[0070] Specifically, the locking mechanism 70 includes a swinging member 701, a contact member 702, and a spring 703 (see FIGS. 2 and 3). The swinging member 701 is swingably supported by a fourth support shaft 701x disposed at a predetermined position inside the main body 1. The contact member 702 is supported by the movable unit 6.

[0071] The swinging member 701 has an arm portion 701a and a locking portion 701b (see FIGS. 6, 9, and 12).

[0072] The arm portion 701a is formed to extend from the portion supported by the fourth support shaft 701x downward from the blocking member 73. The locking portion 701b is continuous with the arm portion 701a.

[0073] The swinging member 701 can swing between a locking position and a release position. When the swinging member 701 is in the locking position, the locking portion 701b locks the blocking member 73. Figure 6 shows the swinging member 701 in the locking position.

[0074] When the swing member 701 is located at the release position, the locking portion 701b releases the locking of the blocking member 73. Figures 9 and 12 show the swing member 701 located at the release position.

[0075] The spring 703 holds the locking portion 701b at the locking position by elastically biasing the swinging member 701. In this embodiment, the spring 703 is a torsion coil spring supported by the fourth support shaft 701x. The spring 703 is an example of an elastic member.

[0076] The swinging member 701 may be configured to swing from the release position to the locking position by its own weight, in which case the spring 703 can be omitted.

[0077] When the movable unit 6 moves from the separated position to the reference position, the contact member 702 comes into contact with the arm portion 701a and moves the swinging member 701 from the locking position to the release position against the biasing force of the spring 703.

[0078] On the other hand, when the movable unit 6 moves from the reference position to the separated position, the contact member 702 moves away from the arm portion 701a, causing the urging force of the spring 703 to move the swinging member 701 from the release position to the locking position.

[0079] 4 to 6 show the electric shock prevention mechanism 7 in a connected state. The connected state is a state in which the second terminal 72 is in contact with the first terminal 71. In the connected state, the second terminal 72 supports the interrupter 73 from below and holds it in the open position. The electric shock prevention mechanism 7 is in the contact state when the movable unit 6 is in the reference position and the swingable member 701 is in the locking position.

[0080] 10 to 12 show the electric shock prevention mechanism 7 in an open state. The open state is a state in which the second terminal 72 is separated from the first terminal 71 and the interrupting member 73. The electric shock prevention mechanism 7 is in the open state when the movable unit 6 is located in the separated position and the swinging member 701 is located in the released position.

[0081] 7 to 9 show the electric shock prevention mechanism 7 in an intermediate state, which is a state between the connected state and the open state.

[0082] When the movable unit 6 moves from the separated position to the reference position, the second terminal 72 moves to a position where it contacts the first terminal 71 via the access path, while moving the blocking member 73, which has been released from the locking position by the locking mechanism 70, from the blocking position to the open position (see Figures 4 to 6).

[0083] On the other hand, when the movable unit 6 moves from the reference position to the separated position, the second terminal 72 moves in the outward direction D11 from the position where it contacts the first terminal 71 and the blocking member 73 (see FIGS. 7 to 12). As a result, the blocking member 73 moves from the open position to the blocking position due to its own weight, and the locking mechanism 70 locks the blocking member 73 at the blocking position.

[0084] The electric shock prevention mechanism 7 may include an elastic member such as a spring that elastically biases the interrupting member 73 toward the interrupting position.

[0085] The electric shock prevention mechanism 7 includes a terminal box 74 that houses a first terminal 71 (see FIGS. 2 to 12). The terminal box 74 is disposed at a predetermined position inside the main body 1. The terminal box 74 has an access opening 74a that forms the access path. The access opening 74a opens the inside of the terminal box 74 in the outward direction D11.

[0086] The blocking member 73 blocks the access opening 74a in the blocking position (see FIGS. 3 and 11), while the blocking member 73 opens the access opening 74a in the open position (see FIGS. 2 and 5).

[0087] For example, the first terminal 71 is a spring that is elastically deformable by the force received from the second terminal 72. In the example shown in Figures 1 to 12, the first terminal 71 is a coil spring. This ensures that the first terminal 71 and the second terminal 72 are kept in contact with each other when the movable unit 6 is located at the reference position. The first terminal 71 may also be a leaf spring.

[0088] The terminal box 74 further has a lower opening 74b formed in the bottom surface of the terminal box 74 (see FIGS. 5, 6, 8, 9, 11, and 12). When the swinging member 701 moves from the release position to the locking position, the locking portion 701b enters through the lower opening 74b into a position within the terminal box 74 along the blocking member 73 (see FIGS. 11 and 12).

[0089] That is, when the swinging member 701 is located at the locking position, the locking portion 701b is located at a position along the interrupting member 73 inside the terminal box 74. As a result, the locking portion 701b locks the interrupting member 73 at the interrupting position.

[0090] As described above, the electric shock prevention mechanism 7 prevents electric shock caused by contact with the first terminal 71 when the movable unit 6 is located at the separated position. Furthermore, the electric shock prevention mechanism 7 is realized with a simple configuration. For example, the electric shock prevention mechanism 7 is realized with a simpler configuration than a mechanism that cuts off the power supply line from the voltage output device 440 to the first terminal 71 in response to movement of the movable unit 6.

[0091] [Notes on the Invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0092] <Appendix 1> an image carrier that carries a developer image; a first terminal for outputting a transfer voltage; a movable unit supported movably between a reference position close to the image carrier and the first terminal and a remote position farther from the image carrier and the first terminal than the reference position; a second terminal supported by the movable unit, contacting the first terminal when the movable unit is located at the reference position and moving away from the first terminal when the movable unit is located at the separated position; a transfer member supported by the movable unit, electrically connected to the second terminal, and configured to transfer the developer image carried on the image carrier to a sheet passing between the transfer member and the image carrier when the movable unit is positioned at the reference position; a blocking member movable between a blocking position where the access path to the first terminal is blocked and an opening position where the access path is opened; a locking mechanism that is linked to movement of the movable unit, locks the blocking member at the blocking position when the movable unit is located at the separated position, and releases the locking of the blocking member when the movable unit moves from the separated position to the reference position, When the movable unit moves from the separated position to the reference position, the second terminal moves to a position where it contacts the first terminal via the access path while moving the blocking member, which has been released from the locking mechanism, from the blocking position to the open position.

[0093] <Appendix 2> a terminal box containing the first terminal and having an access opening that forms the access path; 2. The image forming apparatus according to claim 1, wherein the blocking member blocks the access opening in the blocking position and opens the access opening in the open position.

[0094] <Appendix 3> 3. The image forming apparatus according to claim 1, wherein the first terminal is a spring that is elastically deformable by a force received from the second terminal.

[0095] <Appendix 4> a first conveyance guide disposed adjacent to the image carrier and configured to guide conveyance of the sheet; An image forming apparatus as described in any one of Supplementary Note 1 to Supplementary Note 3, further comprising: a second transport guide supported by the movable unit and forming a part of a sheet transport path between the first transport guide and the second transport guide when the movable unit is positioned at the reference position.

[0096] <Appendix 5> 5. The image forming apparatus according to claim 1, wherein the blocking member moves from the open position to the blocking position by its own weight. [Explanation of symbols]

[0097] 4: Printing device 5: Outer cover 6: Movable unit 7: Electric shock prevention mechanism 10: Image forming device 70:Latching mechanism 71: 1st terminal 72: 2nd terminal 73: Blocking member 74: Terminal box 74a: Access opening 440: Voltage output device 441: Intermediate transfer belt (image carrier) 442: Primary transfer roller 443: Secondary transfer roller (transfer member) 701: Swinging member 701a: Arm part 701b: Locking part 701x: 4th spindle 702: Contact member 703: Spring

Claims

1. an image carrier that carries a developer image; a first terminal for outputting a transfer voltage; a movable unit supported movably between a reference position close to the image carrier and the first terminal and a remote position farther from the image carrier and the first terminal than the reference position; a second terminal supported by the movable unit, contacting the first terminal when the movable unit is located at the reference position and separating from the first terminal when the movable unit is located at the separated position; a transfer member supported by the movable unit, electrically connected to the second terminal, and configured to transfer the developer image carried on the image carrier to a sheet passing between the transfer member and the image carrier when the movable unit is positioned at the reference position; a blocking member movable between a blocking position where the access path to the first terminal is blocked and an opening position where the access path is opened; a locking mechanism that is linked to movement of the movable unit, locks the blocking member at the blocking position when the movable unit is located at the separated position, and releases the locking of the blocking member when the movable unit moves from the separated position to the reference position, When the movable unit moves from the separated position to the reference position, the second terminal moves to a position where it contacts the first terminal via the access path while moving the blocking member, which has been released from the locking mechanism, from the blocking position to the open position.

2. a terminal box containing the first terminal and having an access opening that forms the access path; The image forming apparatus according to claim 1 , wherein the blocking member blocks the access opening in the blocking position and opens the access opening in the open position.

3. 3. The image forming apparatus according to claim 1, wherein the first terminal is a spring that is elastically deformable by a force received from the second terminal.

4. a first conveyance guide disposed adjacent to the image carrier and configured to guide conveyance of the sheet; 3. The image forming apparatus according to claim 1, further comprising: a second transport guide supported by the movable unit and forming a part of the sheet transport path between the first transport guide and the second transport guide when the movable unit is positioned at the reference position.

5. 3. The image forming apparatus according to claim 1, wherein the blocking member moves from the open position to the blocking position by its own weight.

Images