JP5953260B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device that fixes a toner image on a sheet, and an image forming apparatus including the fixing device.

  2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses such as copying machines and printers include a fixing device that fixes a toner image on a sheet. The fixing device includes a first rotating body (for example, a fixing roller or a fixing belt) and a second rotating body (for example, a pressure roller or a pressure belt) that is in pressure contact with the first rotating body. . The sheet passes through the fixing nip formed between the first rotating body and the second rotating body, whereby the sheet and the toner image are heated and pressurized, and the toner image is fixed on the sheet. Yes.

  For example, Patent Document 1 discloses a configuration in which a cover member that can be opened and closed (see “Cover 51” in Patent Document 1) covers the outside of the discharge port of the fixing device. By adopting such a configuration, when a JAM (paper jam) occurs inside the fixing device, the cover member can be opened and the paper sandwiched between the fixing nips can be pulled out. Will improve.

JP-A-6-194898

  In the above prior art, when pulling out the paper sandwiched in the fixing nip, if the leading edge of the paper protrudes downstream from the fixing nip (when the leading edge of the paper is clearly visible), the leading edge of the paper can be easily Can be pinched. However, when the leading edge of the sheet is near the fixing nip (when the leading edge of the sheet is difficult to see), it is difficult to pinch the leading edge of the sheet, and there is a problem that it is difficult to pull out the sheet sandwiched between the fixing nips.

  In view of the above circumstances, an object of the present invention is to improve the workability of JAM processing by allowing a sheet sandwiched between fixing nips to be easily pulled out.

  The fixing device of the present invention forms a fixing nip between a first rotating body provided rotatably and the first rotating body in pressure contact with the first rotating body, and a second rotation provided rotatably. And a discharge position provided on the downstream side of the fixing nip, a closing position that covers the outside of the discharge opening, and an open position that opens the outside of the discharge opening. A cover member, and a rotation for rotating the first rotating body in a direction to convey the sheet from the fixing nip side to the paper discharge port side as the cover member moves from the closed position to the open position. And a mechanism.

  By adopting such a configuration, even when the leading edge of the sheet is in the vicinity of the fixing nip when JAM occurs, the first rotating body and the second rotating body are moved as the cover member is moved from the closed position to the open position. , And the front end of the paper can be pushed out from the fixing nip side to the paper discharge port side. Along with this, it becomes easy to pinch the leading edge of the paper, and the paper sandwiched between the fixing nips can be easily pulled out. Therefore, the workability of JAM processing can be improved.

  The cover member is provided so as to be rotatable between the closed position and the open position, and the rotation mechanism is provided so as to be able to mesh with a drive gear that rotates as the cover member rotates. And a driven gear attached to the first rotating body.

  By adopting such a configuration, the first rotating body can be reliably rotated by the rotation mechanism.

  The fixing device includes a guide member that is rotatably provided between a one-side closing position that covers one side of the paper discharge port and a one-side open position that opens one side of the paper discharge port, the cover member, and the guide A link mechanism that connects the members and rotates the guide member from the one-side closed position to the one-side opened position as the cover member rotates from the closed position to the opened position. good.

  By adopting such a configuration, when the JAM occurs, the guide member is rotated from the one-side closed position to the one-side opened position as the cover member is rotated from the closed position to the one-side open position. Can be released. As a result, the workability of JAM processing can be further improved.

  The drive gear may be provided integrally with the guide member.

  By adopting such a configuration, the configuration of the fixing device can be simplified as compared with the case where the drive gear is provided separately from the guide member. Note that “provided integrally” includes not only the case where the drive gear and the guide member are integrally molded, but also the case where the drive gear and the guide member are fixed.

  The support member further includes a support member that rotatably supports the second rotating body. The support member has a first position where the pressure of the fixing nip is a first pressure, and the pressure of the fixing nip is the first pressure. And a second position that is lower than the second pressure. The link mechanism connects the cover member and the support member, and the cover member is moved from the closed position. The support member may be swung from the first position to the second position as it rotates to the open position.

  By adopting such a configuration, when the JAM is generated, the support member is swung from the first position to the second position as the cover member is rotated from the closed position to the open position, thereby fixing the fixing nip. Can be reduced from the first pressure to the second pressure. For this reason, it is possible to more easily pull out the sheet sandwiched between the fixing nips, and it is possible to further improve the workability of the JAM processing.

  The link mechanism includes a first link arm connected to the cover member, a second link arm connected to the guide member, a third link arm connected to the support member, the first link arm, And a link shaft that connects the second link arm and the third link arm.

  By adopting such a configuration, a link mechanism can be realized with a simple configuration.

  The drive gear is separated from the driven gear in a state where the cover member is in the closed position, and starts to mesh with the driven gear while the cover member rotates from the closed position to the open position. Also good.

  By adopting such a configuration, it is possible to rotate the first rotating body and the driven gear without rotating the drive gear in a state where the cover member is in the closed position.

  The image forming apparatus of the present invention includes any one of the fixing devices described above.

  According to the present invention, the paper sandwiched between the fixing nips can be easily pulled out, and the workability of JAM processing can be improved.

1 is a schematic diagram illustrating an outline of a printer according to an embodiment of the present invention. It is a perspective view from the front side showing a printer concerning one embodiment of the present invention. 1 is a rear perspective view showing a printer according to an embodiment of the present invention. 1 is a side sectional view showing a fixing device of a printer according to an embodiment of the present invention. In the fixing device of the printer according to one embodiment of the present invention, it is a perspective view showing a state in which a cover member is in a closed position. In the fixing device of the printer according to one embodiment of the present invention, FIG. FIG. 6 is a perspective view showing the cover member, the guide member, and the link mechanism when the cover member is in the closed position in the fixing device of the printer according to the embodiment of the present invention. FIG. 5 is a perspective view illustrating a cover member, a guide member, a support member, and a link mechanism when the cover member is in an open position in the printer fixing device according to the embodiment of the present invention. In the fixing device of the printer according to one embodiment of the present invention, it is a side view showing a state in which the cover member is in the closed position. FIG. 6 is a side view illustrating a state where the cover member is in an open position in the fixing device of the printer according to the embodiment of the present invention. In the fixing device of the printer according to an embodiment of the present invention, it is a side view showing a state in the middle of the rotation of the cover member from the closed position to the open position.

  First, the overall configuration of the printer 1 (image forming apparatus) will be described with reference to FIG. Hereinafter, the right side in FIG. 1 is the front side (front side) of the printer 1. An arrow Fr attached to each drawing indicates the front side (front side) of the printer 1.

  The printer 1 includes a box-shaped printer main body 2, a paper feed cassette 3 for storing paper (not shown) is provided at the bottom of the printer main body 2, and a paper discharge tray is provided at the upper end of the printer main body 2. 4 is provided.

  An exposure unit 5 composed of a laser scanning unit (LSU) is disposed at the front of the printer main body 2, and an image forming unit 6 is provided at the rear of the printer main body 2. The image forming unit 6 is rotatably provided with a photosensitive drum 7 serving as an image carrier. Around the photosensitive drum 7, a charger 8 and a developing unit 10 connected to a toner container 9 are provided. The transfer roller 11 and the cleaning device 12 are arranged along the rotation direction of the photosensitive drum 7 (see arrow X in FIG. 1).

  A paper transport path 13 is provided at the rear of the printer main body 2 from below to above. That is, the printer 1 of the present embodiment is so-called “vertical conveyance”. A paper feed unit 14 is provided at the upstream end of the conveyance path 13, and a transfer unit 15 configured by the photosensitive drum 7 and the transfer roller 11 is provided at a middle portion of the conveyance path 13, and a downstream part of the conveyance path 13. Is provided with a fixing device 16. A reverse path 17 for duplex printing is provided on the rear side of the transport path 13.

  Next, an image forming operation of the printer 1 having such a configuration will be described.

  When the printer 1 is turned on, various parameters are initialized, and initial setting such as temperature setting of the fixing device 16 is executed. Then, when image data is input from a computer or the like connected to the printer 1 and an instruction to start printing is given, an image forming operation is executed as follows.

  First, after the surface of the photosensitive drum 7 is charged by the charger 8, exposure corresponding to image data is performed on the photosensitive drum 7 by laser light from the exposure device 5 (see arrow P in FIG. 1). Then, an electrostatic latent image is formed on the surface of the photosensitive drum 7. Next, the developing unit 10 develops the electrostatic latent image into a toner image with the toner supplied from the toner container 9.

  On the other hand, the sheet taken out from the sheet cassette 3 by the sheet feeding unit 14 is conveyed to the transfer unit 15 in synchronization with the above-described image forming operation, and the toner image on the photosensitive drum 7 is transferred to the sheet by the transfer unit 15. Is transcribed. The sheet on which the toner image has been transferred is conveyed downstream in the conveyance path 13 and enters the fixing device 16 where the toner image is fixed on the sheet. The sheet on which the toner image is fixed is discharged from the downstream end of the transport path 13 to the discharge tray 4. The toner remaining on the photosensitive drum 7 is collected by the cleaning device 12.

  Next, the configuration of the fixing device 16 will be described.

  As shown in FIGS. 2 and 3, the fixing device 16 is accommodated in the upper rear corner of the printer main body 2. As shown in FIG. 2, the front side of the fixing device 16 is exposed toward the paper discharge tray 4. As shown in FIG. 3, the rear surface side of the fixing device 16 is covered with a rear cover 18 that can be opened and closed.

  As shown in FIG. 4, the fixing device 16 includes a fixing device body 20 having a box shape, a fixing roller 21 (first rotating body) housed in the lower center of the fixing device body 20, and the fixing device body 20. A pressure roller 22 (second rotating body) accommodated in the rear portion, a cover member 23 covering the upper portion of the fixing device main body 20, and a guide member 24 attached to the upper rear portion of the fixing device main body 20 are provided. .

  A paper feed port 25 is provided on the lower end side of the fixing device main body 20, and a paper discharge port 26 is provided on the upper end side of the fixing device main body 20. The paper introduced into the fixing device main body 20 through the paper supply port 25 is discharged from the fixing device main body 20 through the paper discharge port 26.

  A first frame member 27 is provided at the front portion of the fixing device main body 20. The first frame member 27 is formed with a fixing roller accommodating portion 28.

  A second frame member 30 is provided at the rear portion of the fixing device main body 20. The second frame member 30 faces the first frame member 27 via the paper transport path 13. A pressure roller accommodating portion 31 is formed in the second frame member 30. A discharge switch 32 is provided at the front upper portion of the second frame member 30. The discharge switch 32 rotates around the fulcrum 33 to close the transport path 13 and the reverse path 17 (see the solid line in FIG. 4), and to open the transport path 13 and the reverse path 17 (see FIG. 4). And can be switched.

  The fixing roller 21 has a shape that is long in the left-right direction. The fixing roller 21 is accommodated in a fixing roller accommodating portion 28 provided on the first frame member 27 of the fixing device main body 20. The fixing roller 21 is, for example, a cylindrical core material made of a metal such as aluminum or iron, an elastic layer that is provided around the core material and made of silicon rubber, and the like, and covers the elastic layer, and fluorine such as PFA. And a release layer made of resin.

  A heater 34 (heat source) is accommodated in the internal space of the fixing roller 21. The heater 34 is composed of, for example, a halogen heater or a ceramic heater. The heater 34 is configured to generate heat when energized and to heat the fixing roller 21.

  A separation claw 35 is provided on the upper side of the fixing roller 21 (downstream side in the sheet conveyance direction). The separation claw 35 is in contact with the outer peripheral surface of the fixing roller 21 by a biasing force of a biasing body (not shown). Thereby, the sheet can be separated from the outer peripheral surface of the fixing roller 21 by the separation claw 35.

  The pressure roller 22 is accommodated in a pressure roller accommodating portion 31 provided on the second frame member 30 of the fixing device main body 20. The pressure roller 22 has a long shape in the left-right direction. The pressure roller 22 includes, for example, a cylindrical core material made of a metal such as aluminum or iron, an elastic layer formed around the core material and made of silicon rubber, and the elastic layer. And a release layer made of a fluororesin. The pressure roller 22 is in pressure contact with the fixing roller 21 by an urging force of an urging member (not shown), and forms a fixing nip 29 with the fixing roller 21. The fixing nip 29 is formed on the upstream side of the paper discharge port 26 in the paper transport direction. In other words, the paper discharge port 26 is formed on the downstream side of the fixing nip 29 in the paper transport direction.

  The cover member 23 has a shape that is long in the left-right direction. As shown in FIG. 4, a rotation shaft 38 is provided on the front end side of the cover member 23 along the left-right direction (the depth direction in FIG. 4). A front end portion of the cover member 23 is rotatably attached to the rotation shaft 38. Therefore, the cover member 23 opens to close the outer side (upper side) of the discharge port 26 of the fixing device body 20 (see FIG. 5) and to open the outer side (upper side) of the discharge port 26 of the fixing device body 20. Between the position (refer to FIG. 6), the rotation shaft 38 can be rotated. A discharge roller 39 (see FIG. 4) is pivotally supported on the rotation shaft 38.

  As shown in FIG. 7, the guide member 24 has a shape that is long in the left-right direction. At both left and right ends of the guide member 24, arm portions 36 are provided so as to project in a direction perpendicular to the left and right direction (downward in the drawing of FIG. 7). A cylindrical shaft portion 37 extending in the left-right direction is provided at the distal end portion of the arm portion 36 (the lower end portion in FIG. 7). The shaft portion 37 is rotatably attached to the fixing device main body 20. Therefore, the guide member 24 has a one-side closing position (see FIG. 5) that covers one side (rear side) of the discharge port 26 of the fixing device body 20 and one side (rear side) of the discharge port 26 of the fixing device body 20. It can be rotated around the shaft portion 37 between the open position on one side (see FIG. 6).

  As shown in FIG. 8, the fixing device 16 further includes a pair of left and right support members 40. Each support member 40 is disposed on both the left and right ends of the cover member 23 and the guide member 24. Each support member 40 is formed of sheet metal.

  A bearing portion 41 is provided at a substantially central portion in the vertical direction of each support member 40. The left and right ends of the pressure roller 22 (see FIG. 4) are pivotally supported on the bearing portion 41 of each support member 40. That is, the pressure roller 22 is rotatably supported by each support member 40.

  As shown in FIG. 8, a swing shaft 42 is provided at the lower end of each support member 40. The swing shaft portion 42 is rotatably attached to the fixing device body 20. Therefore, each support member 40 has a first position (see FIG. 9) where the pressure of the fixing nip 29 is the first pressure P1, and a second pressure where the pressure of the fixing nip 29 is lower than the first pressure P1. It can swing around the swinging shaft portion 42 between the second position (see FIG. 10), which is P2.

  As shown in FIG. 8, a connection portion 43 is provided at the upper end portion of each support member 40. The connecting portion 43 is disposed on the opposite side of the swing shaft portion 42 with the bearing portion 41 interposed therebetween. A bent portion 44 that is bent outward in the left-right direction is provided at the front end portion of the connecting portion 43.

  As shown in FIG. 8, the fixing device 16 further includes a link mechanism 45. The link mechanism 45 is disposed on the right end side of the cover member 23 and the guide member 24. The link mechanism 45 includes a first link arm 46 having one end connected to the rear end of the cover member 23 (the end on the side away from the rotation shaft 38), and one end in the width direction of the guide member 24 (the shaft 37). The second link arm 47 whose one end is connected to the end of the support member 40 on the right side, the third link arm 48 whose one end is connected to the connection 43 of the right support member 40, and the first link arm 46. The other end of the second link arm 47, and the other end of the third link arm 48, and a link shaft 49 connecting the other end of the third link arm 48. With the above configuration, the link mechanism 45 connects the cover member 23, the guide member 24, and the right support member 40 to each other.

  As shown in FIGS. 9 to 11, the fixing device 16 further includes a rotation mechanism 51. The rotation mechanism 51 is disposed on the left end side of the cover member 23 and the guide member 24. The rotation mechanism 51 includes a drive gear 52 and a driven gear 53 provided on the front side of the drive gear 52.

  The drive gear 52 is provided integrally with the arm portion 36 of the guide member 24. Note that “provided integrally” means not only when the drive gear 52 and the arm portion 36 of the guide member 24 are integrally molded, but also when the drive gear 52 and the arm portion 36 of the guide member 24 are fixed. Including the case. The drive gear 52 is provided with arc-shaped gear teeth 54.

  The driven gear 53 is attached to the left end portion of the fixing roller 21. The driven gear 53 includes a large-diameter portion 55 and a small-diameter portion 56 provided on the inner side (right side) of the large-diameter portion 55. The large diameter portion 55 of the driven gear 53 is connected to a drive source 57 constituted by a motor or the like.

  A bearing 58 is provided on the inner side (right side) of the driven gear 53, and the fixing roller 21 is pivotally supported on the bearing 58. The bearing 58 includes an engagement piece 59 projecting forward, and the engagement piece 59 is engaged with the fixing device main body 20 (not shown in FIGS. 9 to 11). With such a configuration, the fixing roller 21 is rotatably supported by the fixing device main body 20 via the bearing 58.

  4 and 10 indicate when the sheet is transported from the fixing nip 29 side (upstream side in the sheet transport direction) to the discharge port 26 side (downstream side in the sheet transport direction). The rotation direction of the fixing roller 21 is shown, and this is hereinafter referred to as a rotation direction Y. Further, an arrow Z attached to FIGS. 4 and 10 indicates when the sheet is transported from the fixing nip 29 side (upstream side in the sheet transport direction) to the discharge port 26 side (downstream side in the sheet transport direction). The direction of rotation of the pressure roller 22 is shown, which is hereinafter referred to as the direction of rotation Z.

  The operation of fixing the toner image on the sheet in the fixing device 16 configured as described above will be described.

  When the toner image is fixed on the paper, the fixing roller 21 is heated by the heater 34. Further, the driven gear 53 is rotated by the drive source 57. When the driven gear 53 rotates in this way, the fixing roller 21 rotates in the rotation direction Y and the pressure roller 22 that is in pressure contact with the fixing roller 21 rotates in the rotation direction Z as shown in FIG.

  In this state, when a sheet on which an unfixed toner image is formed is conveyed from the upstream side (downward) along the conveyance path 13, the sheet enters the fixing device main body 20 through the sheet feeding port 25. And passes through the fixing nip 29. As a result, the paper and the toner image are heated and pressurized, and the toner image is fixed on the paper. The paper that has passed through the fixing nip 29 is discharged from the fixing device main body 20 through a paper discharge port 26 provided on the downstream side of the fixing nip 29, and then discharged to the paper discharge tray 4 by a discharge roller 39.

  Next, JAM processing (paper jam processing) will be described.

  When the toner image is fixed on the sheet as described above, as shown in FIG. 5, the cover member 23 is in the closed position, and the guide member 24 is in the one-side closed position. Further, as shown in FIG. 7, the first link arm 46 and the second link arm 47 of the link mechanism 45 are in a folded state. As shown in FIG. 9, the support member 40 is in the first position, and the pressure in the fixing nip 29 is the first pressure P1. The drive gear 52 is separated from the driven gear 53.

  In this state, when a JAM (paper jam) occurs in the fixing device 16, an operator such as a user or a serviceman opens the rear cover 18 (see FIG. 3), and the rear end side of the cover member 23 of the fixing device 16. Lift up. Accordingly, as shown in FIG. 6, the cover member 23 rotates from the closed position to the open position, and the first link arm 46 and the second link arm 47 of the link mechanism 45 are opened, and the guide member 24 rotates from the one-side closing position to the one-side opening position.

  When the guide member 24 rotates in this way, the drive gear 52 provided integrally with the arm portion 36 of the guide member 24 rotates (see arrow A in FIG. 11). At that time, the guide teeth 24 are rotated from the one-side closed position to the one-side opened position (while the cover member 23 is rotated from the closed position to the opened position), as shown in FIG. 54 starts meshing with the small diameter portion 56 of the driven gear 53. As shown in FIG. 10, when the guide member 24 rotates to the one-side open position (when the cover member 23 rotates to the open position), the drive gear 52 further rotates accordingly. The rotation of the driving gear 52 is transmitted to the fixing roller 21 through the driven gear 53, and the fixing roller 21 rotates in the rotation direction Y by a certain angle. Along with this, the pressure roller 22 in pressure contact with the fixing roller 21 rotates in the rotation direction Z by a certain angle. As a result, the leading edge of the sheet sandwiched between the fixing nips 29 is pushed out from the fixing nip 29 side to the discharge port 26 side by a certain amount.

  When the first link arm 46 and the second link arm 47 of the link mechanism 45 are opened as described above, the third link arm 48 of the link mechanism 45 is moved to the rear as shown by the arrow B in FIG. Pulled upward. Accordingly, as shown by an arrow C in FIG. 10, the support roller 40 swings from the first position to the second position, and the pressure roller 22 rotatably supported by the support member 40 is It moves in a direction away from the fixing roller 21 (backward in this embodiment). Along with this, the pressure in the fixing nip 29 decreases from the first pressure P1 to the second pressure P2.

  As described above, the fixing device 16 according to the present embodiment rotates in the direction in which the sheet is conveyed from the fixing nip 29 side to the paper discharge port 26 side as the cover member 23 rotates from the closed position to the open position. The mechanism 51 is configured to rotate the fixing roller 21. By adopting such a configuration, even when the leading edge of the sheet is in the vicinity of the fixing nip 29 when JAM occurs, the fixing roller 21 and the pressure roller are rotated as the cover member 23 is rotated from the closed position to the open position. 22 can be rotated to push the leading edge of the paper from the fixing nip 29 side to the paper discharge port 26 side. Along with this, it becomes easy to pinch the leading edge of the paper, and the paper sandwiched between the fixing nips 29 can be easily pulled out. Therefore, the workability of JAM processing can be improved.

  The rotation mechanism 51 includes a drive gear 52 that rotates with the rotation of the cover member 23, and a driven gear 53 that can be engaged with the drive gear 52 and attached to the fixing roller 21. By adopting such a configuration, the fixing roller 21 can be reliably rotated by the rotation mechanism 51.

  Further, the fixing device 16 of the present embodiment is configured such that the link mechanism 45 rotates the guide member 24 from the one-side closed position to the one-side opened position as the cover member 23 rotates from the closed position to the opened position. ing. By adopting such a configuration, when the JAM occurs, the guide member 24 is rotated from the one-side closed position to the one-side opened position as the cover member 23 is rotated from the closed position to the opened position. One side of 26 can be opened. As a result, the workability of JAM processing can be further improved.

  Further, the drive gear 52 of the rotation mechanism 51 is provided integrally with the guide member 24. By adopting such a configuration, the configuration of the fixing device 16 can be simplified as compared with the case where the drive gear 52 is provided separately from the guide member 24.

  In the fixing device 16 of the present embodiment, the link mechanism 45 swings the support member 40 from the first position to the second position as the cover member 23 rotates from the closed position to the open position. It is configured. By adopting such a configuration, when JAM occurs, the support member 40 is swung from the first position to the second position as the cover member 23 is rotated from the closed position to the open position. It becomes possible to reduce the pressure of the fixing nip 29 from the first pressure P1 to the second pressure P2. Therefore, it is possible to more easily pull out the paper sandwiched between the fixing nips 29, and it is possible to further improve the workability of JAM processing.

  The link mechanism 45 includes a first link arm 46 connected to the cover member 23, a second link arm 47 connected to the guide member 24, a third link arm 48 connected to the support member 40, 1 link arm 46, 2nd link arm 47, and link shaft 49 which connects the 3rd link arm 48 are provided. By adopting such a configuration, the link mechanism 45 can be realized with a simple configuration.

  Further, the drive gear 52 is separated from the driven gear 53 in a state where the cover member 23 is in the closed position, and starts to mesh with the driven gear 53 while the cover member 23 rotates from the closed position to the open position. It is configured. By adopting such a configuration, it is possible to rotate the fixing roller 21 and the driven gear 53 without rotating the drive gear 52 in a state where the cover member 23 is in the closed position.

  In this embodiment, the case where the cover member 23 rotates between the closed position and the open position has been described. However, in another different embodiment, the cover member 23 slides linearly between the closed position and the open position. You may do it.

  Although the case where the drive gear 52 is provided integrally with the guide member 24 has been described in the present embodiment, the drive gear 52 may be provided separately from the guide member 24 in other different embodiments.

  In the present embodiment, the pressure of the fixing nip 29 is set to two stages of the first pressure P1 and the second pressure P2. However, in another different embodiment, the pressure of the fixing nip 29 may be switched to three or more stages. .

  In the present embodiment, the case where the pressure roller 22 is in pressure contact with the fixing roller 21 in the state where the support member 40 is in the second position has been described. On the other hand, in another different embodiment, the pressure roller 22 may be separated from the fixing roller 21 in a state where the support member 40 is in the second position. That is, the second pressure P2 may be zero.

  In this embodiment, the case where the first rotating body is configured by the fixing roller 21 and the second rotating body is configured by the pressure roller 22 has been described. On the other hand, in other different embodiment, you may comprise one or both of a 1st rotary body and a 2nd rotary body with a belt.

  In this embodiment, the case where the heater 34 is used as the heat source has been described. However, in another different embodiment, another heat source such as an IH coil may be used.

  In this embodiment, the case where the configuration of the present invention is applied to the printer 1 has been described. However, in another different embodiment, the configuration of the present invention is applied to other image forming apparatuses such as a copying machine, a facsimile machine, and a multifunction machine. It is also possible.

1 Printer (image forming device)
16 Fixing device 21 Fixing roller (first rotating body)
22 Pressure roller (second rotating body)
23 cover member 24 guide member 26 sheet discharge port 29 fixing nip 40 support member 45 link mechanism 46 first link arm 47 second link arm 48 third link arm 49 link shaft 51 rotating mechanism 52 drive gear 53 driven gear

Claims (6)

A first rotating body provided rotatably,
A second rotator that is rotatably contacted with the first rotator to form a fixing nip with the first rotator;
A paper discharge port provided on the downstream side of the fixing nip;
A cover member rotatably provided between a closed position that covers the outside of the paper discharge port and an open position that opens the outside of the paper discharge port;
A rotation mechanism that rotates the first rotating body in a direction to convey a sheet from the fixing nip side to the paper discharge port side as the cover member rotates from the closed position to the open position;
A guide member rotatably provided between a one-side closing position that covers one side of the paper discharge port and a one-side open position that opens one side of the paper discharge port;
A link mechanism that connects the cover member and the guide member, and rotates the guide member from the one-side closed position to the one-side open position as the cover member rotates from the closed position to the open position; equipped with a,
The rotation mechanism is
A drive gear that rotates as the cover member rotates;
And a driven gear attached to the first rotating body so as to be able to mesh with the drive gear . The fixing device according to claim 1 , wherein the driving gear is provided integrally with the guide member. The support member further includes a support member that rotatably supports the second rotating body. The support member has a first position where the pressure of the fixing nip is a first pressure, and the pressure of the fixing nip is the first pressure. And a second position that is a second pressure lower than the pressure, and is swingable between the second position and
The link mechanism connects the cover member and the support member, and moves the support member from the first position to the second position as the cover member rotates from the closed position to the open position. the fixing device according to claim 1 or 2, characterized in that swinging up. The link mechanism is
A first link arm connected to the cover member;
A second link arm connected to the guide member;
A third link arm connected to the support member;
The fixing device according to claim 3 , further comprising: a link shaft that connects the first link arm, the second link arm, and the third link arm. A first rotating body provided rotatably,
A second rotator that is rotatably contacted with the first rotator to form a fixing nip with the first rotator;
A paper discharge port provided on the downstream side of the fixing nip;
A cover member rotatably provided between a closed position that covers the outside of the paper discharge port and an open position that opens the outside of the paper discharge port;
A rotation mechanism that rotates the first rotating body in a direction to convey a sheet from the fixing nip side to the paper discharge port side as the cover member rotates from the closed position to the open position; Prepared,
The rotation mechanism is
A drive gear that rotates as the cover member rotates;
A driven gear provided to be able to mesh with the drive gear and attached to the first rotating body,
The drive gear is separated from the driven gear in a state where the cover member is in the closed position, and starts to mesh with the driven gear while the cover member is rotating from the closed position to the open position. constant Chakusochi said. An image forming apparatus characterized in that it comprises a fixing device according to any one of claims 1-5.

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