This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2021-207797 filed on Dec. 22, 2021, the entire contents of which are incorporated herein by reference.
The present disclosure relates to an electrophotographic image forming apparatus including a heating unit and a fixing unit.
An electrophotographic image forming apparatus transfers a toner image from an image carrier to a sheet, and fixes the toner image on the sheet with a fixing device.
The fixing device may be divided into a heating unit including a heater and a fixing unit including a fixing member and a pressure roller. The heater heats the fixing member.
In addition, it is known that the image forming apparatus includes a mechanism for moving the heating unit from a heating position to a retracted position in conjunction with an operation on an operation portion. When the heating unit is retracted to the retracted position, the fixing unit can be pulled out from the main body.
An image forming apparatus according to one aspect of the present disclosure includes a main body frame, a heating unit, and a fixing unit. The heating unit is supported by the main body frame. The fixing unit is disposed next to the heating unit and supported by the main body frame. The main body frame includes two struts and two beams. The two struts extend in a vertical direction beside the fixing unit and are spaced apart from each other in a first direction. The two beams extend in a lateral direction below the heating unit and the fixing unit, are spaced apart from each other in the first direction, and are coupled to the two struts, respectively. The fixing unit is disposed between the heating unit and the two struts. The heating unit includes a heater and a first support body. The first support body supports the heater and is placed on the two beams in a state of being bridged over the two beams. The fixing unit includes a fixing member, a pressure member, and a second support body. The fixing member is heated by the heater. The pressure member urges a sheet toward the fixing member. The second support body supports the fixing member and the pressure member and is placed on the two beams in a state of being bridged over the two beams. The image forming apparatus further includes an elastic heating unit urging member, an operating portion, and an interlocking mechanism. The heating unit urging member urges the first support body toward the second support body with elastic force so as to bring the first support body into contact with the second support body and bring the second support body into contact with the two struts. The operation portion is movable between a first position and a second position by being operated. The interlocking mechanism moves the heating unit along a second direction, which is a direction in which the heating unit and the fixing unit are arranged, in conjunction with movement of the operation portion. The interlocking mechanism moves the first support body from a reference position where the first support body is in contact with the second support body to a retracted position where the first support body is separated from the second support body when the operation portion moves from the first position to the second position. Further, the interlocking mechanism moves the first support body member from the retracted position to the reference position when the operation portion moves from the second position to the first position. The fixing unit is allowed to be pulled out from the main body frame in a removal direction along the first direction when the first support body is at the retracted position.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description with reference where appropriate to the accompanying drawings. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
Hereinafter, an embodiment will be described with reference to the drawings. It is noted that the following embodiment is an example of embodying the present disclosure and does not limit the technical scope of the present disclosure.
An image forming apparatus 10 according to the embodiment executes print processing using an electrophotographic method. The print processing is processing for forming an image on a sheet 9.
As shown in
The sheet storing portion 2 can house a plurality of sheets 9. The sheet conveying device 3 includes a sheet feeding device 30, and a plurality of conveying roller pairs 31.
The sheet feeding device 30 feeds the sheets 9 in the sheet storing portion 2 one by one to a conveying path 300. The conveying path 300 is a passage of the sheet 9.
The conveying roller pairs 31 convey the sheet 9 along the conveying path 300. One of the conveying roller pairs 31 discharges the sheet 9 on which an image has been formed from the conveying path 300 onto a discharge tray 10a.
The printing device 4 executes the print processing on the sheet 9 conveyed along the conveying path 300. The image formed on the sheet 9 is a toner image.
The printing device 4 includes a laser scanning unit 40, one or more image forming portions 4x, a transfer device 45, and a fixing device 5. The image forming portions 4x each include a photoconductor 41, a charging device 42, a developing device 43, and a drum cleaning device 44.
The charging device 42 charges the surface of the photoconductor 41. The laser scanning unit 40 scans the surface of the charged photoconductor 41 with a light beam. Thus, the laser scanning unit 40 forms an electrostatic latent image on the surface of the photoconductor 41.
The developing device 43 supplies toner to the surface of the photoconductor 41 to develop the electrostatic latent image into a toner image. The transfer device 45 transfers the toner image formed on the surface of the photoconductor 41 to the sheet 9.
The transfer device 45 transfers the toner image to the sheet 9 at a transfer position P1 on the conveying path 300.
In the present embodiment, the printing device 4 is a tandem type color printing device including a plurality of image forming portions 4x. In addition, the transfer device 45 includes an intermediate transfer belt 450, a plurality of primary transfer devices 451, a secondary transfer device 452, and a belt cleaning device 453.
In the example shown in
The intermediate transfer belt 450 is rotatably supported by a plurality of support rollers 454. One of the support rollers 454 is rotated by being driven by a belt drive device (not shown). Thus, the intermediate transfer belt 450 rotates.
The primary transfer devices 451 transfer the toner images formed on the surface of the photoconductor 41 by the respective image forming portions 4x to the surface of the intermediate transfer belt 450. Thus, a composite toner image, in which the toner images of four colors are combined, is formed on the surface of the intermediate transfer belt 450.
The intermediate transfer belt 450 rotates while carrying the composite toner image. The secondary transfer device 452 transfers the composite toner image formed on the surface of the intermediate transfer belt 450 to the sheet 9 at the transfer position P1.
The drum cleaning device 44 removes primary waste toner from the surface of the photoconductor 41. The primary waste toner is toner remaining on a portion of the surface of the photoconductor 41 that has passed through the primary transfer device 451.
The belt cleaning device 453 removes secondary waste from the surface of the intermediate transfer belt 450. The secondary waste toner is toner remaining on a portion of the surface of the intermediate transfer belt 450 that has passed through the secondary transfer device 452.
The fixing device 5 heats and presses the composite toner image on the sheet 9 at a fixing position P2 on the conveying path 300. Thus, the fixing device 5 fixes the composite toner image on the sheet 9. The fixing position P2 is a position downstream of the transfer position P1 in the sheet conveying direction.
As shown in
The fixing belt 52 is a flexible cylindrical member that encloses the fixing roller 520. The fixing belt 52 is heated by the heater 51.
The fixing roller 520 is a cylindrical member that supports the fixing belt 52 inside the fixing belt 52. The fixing roller 520 includes a cylindrical core metal portion 521 and an elastic portion 522 formed on the outer periphery of the core metal portion 521.
The fixing roller 520 is rotatably supported. The fixing belt 52 can rotate together with the fixing roller 520.
The fixing belt 52 includes a conductive base material, an elastic layer formed on the outer periphery of the base material, and a release layer formed on the outer periphery of the elastic layer.
The heater 51 is disposed to face the outer peripheral surface of the fixing belt 52. In the present embodiment, the heater 51 is an electromagnetic induction heating device. The heater 51 mainly heats the base material of the fixing belt 52 by electromagnetic induction.
The pressure roller 53 is rotatably supported. Like the fixing roller 520, the pressure roller 53 also includes a cylindrical core metal portion 531 and an elastic portion 532 formed on the outer periphery of the core metal portion 531.
The pressure roller 53 is rotated by being driven by a drive device (not shown). The fixing belt 52 and the fixing roller 520 rotate in conjunction with the pressure roller 53.
The fixing belt 52 heats the toner image formed on the sheet 9. The pressure roller 53 presses the toner image toward the sheet 9.
It is noted that the fixing belt 52 is an example of a fixing member heated by the heater 51. The pressure roller 53 is an example of a pressure member that urges the sheet 9 to the fixing belt 52.
When the sheet 9 adheres to the fixing belt 52, the sheet separating member 5200 peels the sheet 9 from the fixing belt 52.
In the present embodiment, the fixing device 5 is divided into a heating unit 5a and a fixing unit 5b (see
The first support body 54 is a member that supports the heater 51. The second support body 55 is a member that supports the fixing belt 52, the fixing roller 520, and the pressure roller 53. The fixing belt 52 is supported by the second support body 55 via the fixing roller 520.
The fixing unit 5b can be pulled out from the main body portion 1 by moving the heating unit 5a away from the fixing unit 5b (see
It is important to dispose the heater 51 at an appropriate position with respect to the fixing belt 52 in order to increase the heating efficiency of the fixing belt 52 by the heater 51. When an electromagnetic induction heating device is employed as the heater 51, the accuracy of the position of the heater 51 is particularly important.
On the other hand, it is preferable that a unit positioning mechanism for disposing the heating unit 5a and the fixing unit 5b at desired positions is as simple as possible.
The unit positioning mechanism includes a mechanism for positioning the heating unit 5a at a reference position close to the fixing unit 5b and a mechanism for moving the heating unit 5a to a retracted position away from the fixing unit 5b.
The image forming apparatus 10 uses a simple mechanism to realize the mechanism for disposing the heating unit 5a and the fixing unit 5b at desired positions. Hereinafter, the mechanism for positioning the heating unit 5a and the fixing unit 5b will be described.
The main body portion 1 of the image forming apparatus 10 includes a main body frame 1x and an exterior member 100 covering the main body frame 1x (see
The main body frame 1x is composed of a combination of a plurality of metal pipes (see
The exterior member 100 is attached to the main body frame 1x (see
The metal pipes constituting the main body frame 1x include two struts 11 and two beams 12 (see
The two struts 11 extend in a vertical direction D3, and spaced apart from each other in a first direction D1 (see
The two struts 11 extend in the vertical direction D3 beside the fixing unit 5b (see
The first direction D1 is also a direction along the rotational center lines of the fixing belt 52 and the pressure roller 53. In the present embodiment, the first direction D1 is the depth direction of the image forming apparatus 10.
The exterior member 100 has an opening portion 101 and a cover member 102 (see
The cover member 102 is supported by a first support shaft 102x. Thus, the cover member 102 is rotatable around the first support shaft 102x. The cover member 102 is rotatable between a closed position to close the opening portion 101 and an open position to open the opening portion 101.
When the cover member 102 is in the closed position, the cover member 102 is held in the closed position by a lock mechanism (not shown). When the lock by the lock mechanism is released, the cover member 102 can be rotated from the closed position to the open position.
The two struts 11 include a first strut 11a disposed on the front side of the image forming apparatus 10 and a second strut 11b disposed on the rear side of the image forming apparatus 10 (see
The two beams 12 extend in a lateral direction below the heating unit 5a and the fixing unit 5b, and are spaced apart from each other in the first direction D1 (see
The two beams 12 are respectively coupled to the two struts 11 (see
The two beams 12 include a first beam 12a disposed on the front side of the image forming apparatus 10 and a second beam 12b disposed on the rear side of the image forming apparatus 10 (see
The fixing unit 5b is disposed between the heating unit 5a and the two struts 11 (see
The first support body 54 of the heating unit 5a is placed on the two beams 12 in a state of being bridged over the two beams 12. Similarly, the second support body 55 of the fixing unit 5b is placed on the two beams 12 in a state of being bridged over the two beams 12.
That is, neither the heating unit 5a nor the fixing unit 5b is fixed to the main body frame 1x by a fixing tool such as a screw.
The heating unit 5a and the fixing unit 5b are placed on the two beams 12 with their longitudinal directions aligned with the first direction D1 (see
The heating unit 5a and the fixing unit 5b are arranged side by side in a second direction D2.
That is, the second direction D2 is a direction in which the heating unit 5a and the fixing unit 5b are arranged. The second direction D2 is a direction that intersects the first direction D1.
The image forming apparatus 10 further includes a first spring 60 and an interlocking mechanism 6 (see
The first spring 60 urges the first support body 54 toward the second support body 55 with elastic force (see
The urging force F1 of the first spring 60 to the first support body 54 is greater than the static friction force of the heating unit 5a and the fixing unit 5b against the two beams 12.
The first support body 54 has a plurality of ribs 541 in contact with the upper surfaces of the two beams 12. Similarly, the second support body 55 has a plurality of ribs 551 in contact with the upper surfaces of the two beams 12. The ribs 541 of the first support body 54 and the ribs 551 of the second support body 55 are provided to reduce the static friction force.
The first spring 60 urges the first support body 54 to bring the first support body 54 into contact with the second support body 55. Further, the first spring 60 urges the first support body 54 to bring the second support body 55 into contact with the two struts 11. That is, the first spring 60 urges the second support body 55 via the first support body 54.
The first support body 54 has a plurality of concave first fitting portions 542 that open laterally (see
The second support body 55 has a plurality of convex second fitting portions 553 which can fit into the first fitting portions 542, respectively. The second support body 55 has four second fitting portions 553 corresponding to the four first fitting portions 542.
The first spring 60 urges the first support body 54 to bring the inner surfaces of the concave portions of the four first fitting portions 542 into contact with the four second fitting portions 553 (see
In addition, by the second fitting portions 553 fitting into the first fitting portions 542, the relative movement of the first support body 54 and the second support body 55 in the vertical direction D3 is restricted.
It is noted that the second support body 55 may have the first fitting portions 542 and the first support body 54 may have the second fitting portions 553.
In addition, the second support body 55 has a plurality of strut contact portions 552 projecting toward the two struts 11 (see
The interlocking mechanism 6 moves the heating unit 5a along the second direction D2 in conjunction with the movement of the cover member 102.
When the cover member 102 is moved from the closed position to the open position, the interlocking mechanism 6 moves the first support body 54 of the heating unit 5a from a reference position to a retracted position (see
The reference position is the position of the first support body 54 when the first support body 54 is in contact with the second support body 55. The retracted position is the position of the first support body 54 when the first support body 54 is separated from the second support body 55.
When the first support body 54 is moved from the reference position to the retracted position, the four second fitting portions 553 are separated from the four first fitting portions 542 (see
It is noted that the first support body 54 being at the reference position is synonymous with the heating unit 5a being at the reference position. In addition, the first support body 54 being at the retracted position is synonymous with the heating unit 5a being at the retracted position.
When the first support body 54 is at the retracted position, the fixing unit 5b can be pulled out from the main body frame 1x in a removal direction D11 along the first direction D1 (see
When the fixing unit 5b is pulled out from the main body frame 1x, the fixing unit 5b can pass through the opening portion 101 of the exterior member 100.
Meanwhile, when the cover member 102 is moved from the open position to the closed position, the interlocking mechanism 6 moves the first support body 54 from the retracted position to the reference position (see
When the first support body 54 is moved from the retracted position to the reference position, the four second fitting portions 553 fit into the four first fitting portions 542 (see
The cover member 102 also serves as an operation portion that can be moved between a first position and a second position by being operated. The closed position of the cover member 102 is the first position of the operation portion. The open position of the cover member 102 is the second position of the operation portion.
For example, the interlocking mechanism 6 includes an action member 61, two first link members 62, a second link member 63, and a third link member 64 (see
The action member 61 is disposed to be movable along the second direction D2. The two first link members 62 are coupled to the action member 61 by two first coupling shafts 611. The second link member 63 is coupled to the two first link members 62 by two second coupling shafts 621.
The third link member 64 is supported by a second support shaft 640. The third link member 64 is rotatable around the second support shaft 640. The third link member 64 is coupled to the second link member 63 by a third coupling shaft 631. The cover member 102 is coupled to the third link member 64 by a fourth coupling shaft 641.
The interlocking mechanism 6 shown in
When the cover member 102 rotates, the second link member 63 is moved along the first direction D1 by the action of the third link member 64.
When the second link member 63 moves along the first direction D1, the action member 61 is moved along the second direction D2 by the action of the first link member 62.
When the cover member 102 moves from the closed position to the open position, the interlocking mechanism 6 moves the action member 61 away from the fixing unit 5b. When the cover member 102 moves from the open position to the closed position, the interlocking mechanism 6 moves the action member 61 toward the fixing unit 5b.
The first spring 60 is disposed between the action member 61 and the first support body 54 of the heating unit 5a (see
When the action member 61 pushes the first spring 60 toward the first support body 54, the first spring 60 urges the first support body 54 toward the reference position.
The action member 61 has an engaging portion 612 that can engage with an engaged portion 543 of the first support body 54 (see
When the action member 61 moves away from the first support body 54 along the second direction D2, the first support body 54 receives force from the action member 61 through the engaging portion 612 and moves from the reference position to the retracted position (see
In contrast, when the action member 61 moves toward the first support body 54 along the second direction D2, the first support body 54 receives force from the action member 61 through the first spring 60 and moves from the retracted position to the reference position (see
The heating unit 5a and the fixing unit 5b are positioned in the second direction D2 by being sandwiched between the first spring 60 and the two struts 11.
It is noted that the interlocking mechanism 6 may include a gear mechanism such as a rack-and-pinion mechanism. Also in this case, the interlocking mechanism 6 converts the rotating motion of the cover member 102 into the moving motion of the action member 61 along the second direction D2.
In addition, the heating unit 5a and the fixing unit 5b are positioned in the vertical direction D3 by being placed on the two beams 12. The load of the heating unit 5a and the fixing unit 5b restricts the upward movement of the heating unit 5a and the fixing unit 5b.
As shown in
The fixing unit 5b includes a driven gear 530 that meshes with the drive gear 70. The driven gear 530 transmits the rotational force received from the drive gear 70 to the fixing roller 520. Thus, the fixing member 52 rotates. That is, the driven gear 530 transmits the rotational force to the fixing belt 52 via the fixing roller 520.
The pressure roller 53 rotates in conjunction with the rotating fixing belt 52. It is noted that the driven gear 530 is also a gear that transmits the rotational force to the pressure roller 53 via the fixing roller 520 and the fixing belt 52.
The direction of pressure F2 that the teeth of the driven gear 530 receive from the teeth of the drive gear 70 is obliquely downward toward the two struts 11. Therefore, the pressure F2 that the teeth of the driven gear 530 receive from the teeth of the drive gear 70 acts as force that urges the fixing unit 5b toward the two struts 11 and the two beams 12.
The fixing unit 5b is more firmly positioned in the second direction D2 and the vertical direction D3 by the pressure F2 received from the drive gear 70. In addition, the heating unit 5a is firmly positioned in the vertical direction D3 together with the fixing unit 5b by the action of the first fitting portions 542 and the second fitting portions 553.
In the present embodiment, the drive mechanism 7 also serves as a downward urging mechanism that urges the fixing unit 5b downward.
In addition, the image forming apparatus 10 further includes a cover urging mechanism 8 attached to the inner surface of the cover member 102 (see
The cover urging mechanism 8 includes a second spring 80, a spring case 81, and a cap 82 (see
The spring case 81 houses the second spring 80. The cap 82 is movably attached to the spring case 81. The second spring 80 is an example of an elastic fixing unit urging member.
The second spring 80 is sandwiched between the cover member 102 and the second support body 55 of the fixing unit 5b when the cover member 102 is in the closed position. In the present embodiment, the second spring 80 and the cap 82 are sandwiched between the cover member 102 and the second support body 55.
When the second spring 80 is sandwiched between the cover member 102 and the second support body 55, the second spring 80 urges the second support body 55 in a mounting direction D12 with elastic force (see
The force received by the second support body 55 from the second spring 80 when the cover member 102 is in the closed position brings the beam contact portion 554 into contact with a side surface of one of the two beams 12. In the present embodiment, the beam contact portion 554 comes into contact with a side surface of the second beam 12b.
The fixing unit 5b is positioned in the first direction D1 by the action of the second spring 80 and the beam contact portion 554.
It is noted that the cover urging mechanism 8 may be attached to the second support body 55 of the fixing unit 5b.
In addition, each of the struts 11 has side surfaces on four sides. The four side surfaces of each of the struts 11 each have two raised portions 1p forming ridge lines along the longitudinal direction of the strut 11 (see
The strut contact portions 552 of the second support body 55 are each brought into contact with the two raised portions 1p of the corresponding one of the two struts 11. Thus, the fixing unit 5b is stably positioned in the second direction D2.
Similarly, each of the beams 12 also has side surfaces on four sides. The four side surfaces of each of the bream 12 each have two raised portions 1p forming ridge lines along the longitudinal direction of the bream 12 (see
The ribs 551 of the second support body 55 are each in contact with the two raised portions 1p of the corresponding one of the two breams 12. Thus, the fixing unit 5b is stably positioned in the vertical direction D3.
By employing the image forming apparatus 10, the positioning mechanism for disposing the heating unit 5a and the fixing unit 5b at desired positions can be realized by a simple mechanism.
It is to be understood that the embodiments herein are illustrative and not restrictive, since the scope of the disclosure is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.
Number | Date | Country | Kind |
---|---|---|---|
2021-207797 | Dec 2021 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
5049945 | Fukano | Sep 1991 | A |
7505713 | Lee | Mar 2009 | B2 |
8824926 | Egi | Sep 2014 | B2 |
20060147226 | Sato | Jul 2006 | A1 |
20100178088 | Koshida | Jul 2010 | A1 |
20140255065 | Takahashi | Sep 2014 | A1 |
20140369730 | Bayerle | Dec 2014 | A1 |
20160124382 | Uehara | May 2016 | A1 |
20160202650 | Yoshida | Jul 2016 | A1 |
20180032028 | Watatani | Feb 2018 | A1 |
20180210382 | Ishii | Jul 2018 | A1 |
20210165352 | Sato | Jun 2021 | A1 |
Number | Date | Country |
---|---|---|
2021086093 | Jun 2021 | JP |
Number | Date | Country | |
---|---|---|---|
20230195013 A1 | Jun 2023 | US |