JP7158911B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus, such as a copier or a printer, having a switching member for selectively switching paths for guiding recording materials, and a unit that can be inserted into and removed from the apparatus main body.

2. Description of the Related Art Conventionally, there has been proposed an image forming apparatus such as a copying machine or a printer that has a flapper for selectively switching a path for guiding a recording material and a fixing device that can be inserted into and removed from the main body of the apparatus. As an image forming apparatus to which this kind of relationship between a flapper and an insertable/removable fixing device is applied, an image forming apparatus such as that described in Patent Document 2 is known. Further, Japanese Patent Application Laid-Open No. 2002-200002 describes an image forming apparatus having a fixing device that can be inserted into and removed from the apparatus main body.

In other words, in view of replaceability and operability in the event of a paper jam (jam), there is a demand for stress-free attachment and detachment of the fixing device to be inserted/removed from the main body of the image forming apparatus and the unit to be opened/closed.

The configuration described in Patent Document 2 will be described with reference to FIGS. 17 and 18. FIG. As shown in FIGS. 17 and 18, the door 200 is provided to be openable and closable with respect to the image forming apparatus. The door 200 is opened as indicated by the dashed line in FIG. 18 when handling a paper jam or replacing the fixing device. Then, along with the opening operation of the door 200, the flapper 202 on the downstream side of the fixing device 201 in the recording material conveying direction is freed from the restriction of the abutting portion 200a of the door 200, and becomes the retracted position. As a result, the fixing device 201 can be inserted and removed without contacting the flapper 202 .

JP 2016-75752 A JP 2014-130376 A

On the other hand, in order to save installation space and save energy during distribution, there is a demand to reduce the size of the image forming apparatus main body and to reduce the weight of the image forming apparatus main body by simplifying the component configuration.

However, as described in Patent Document 2, when the flapper 202 is in the retracted position when the door 200 is opened, an abutting portion 200a for abutting the flapper 202 against the door 200 is required. In particular, when the flapper is arranged at a recessed position in the image forming apparatus main body, the abutment portion must also be arranged at a recessed position in the image forming apparatus main body.

That is, in the configuration of Patent Document 2, the rotation locus of the door 200 provided with the abutting portion 200a for abutting against the flapper 202 becomes large, and the size of the image forming apparatus main body becomes large. In addition, if a complicated link structure is used for rotation in order to reduce the rotation trajectory, a large number of parts are required, resulting in an increase in the weight of the image forming apparatus.

An object of the present invention is to suppress an increase in the size and weight of an image forming apparatus main body.

In order to achieve the above object, the present invention provides an apparatus main body having an image forming section for forming an image on a recording material, a unit detachably attached to the apparatus main body, and a unit rotatably attached to the apparatus main body. a switching member for selectively switching a path for guiding a recording material in a state of being inserted into the unit mounted on the apparatus main body, the image forming apparatus comprising: and retracting means for retracting the switching member to the outside of the mounting area of the unit in the process of removing the unit from the apparatus main body, wherein the retracting means can abut or separate from the switching member. and is urged in a direction to retract the switching member to the outside of the mounting area of the unit. It is separated from the switching member against the urging force, and in the process of removing the unit from the apparatus main body, the abutting state between the unit and the retracting means is released, thereby urging the retracting means. The retracting means is brought into contact with the switching member by an urging force, and retracts the switching member to the outside of the mounting area of the unit .

According to the present invention, it is possible to suppress an increase in the size and weight of the image forming apparatus main body.

Schematic cross-sectional view showing an example of an image forming apparatus Schematic diagram with the right door of the image forming apparatus opened Schematic diagram of the fixing device FIG. 2 is a perspective view of a pressure applying mechanism of the fixing device; Cross-sectional view of a pressure applying mechanism of the fixing device Perspective view of the fixing device FIG. 4 is a diagram of the flapper abutting components provided in the fixing device; Schematic diagram of insertion/extraction mechanism of fixing device Component diagram of the ejected paper reversing unit of the image forming apparatus Image forming apparatus flapper rotation link mechanism parts diagram Component diagram of the ejected paper reversing section in the process of pulling out the fixing device (a) is a perspective view of the periphery of the insertion link with the fixing device attached, and (b) is a perspective view of the periphery of the insertion link in the process of removing the fixing device. Component diagram of the output reversing unit with the fixing device removed (a) and (b) are diagrams showing how the fixing device is inserted into and removed from the main body of the apparatus. (a) to (c) are diagrams showing the movement of the flapper seen from the front side of the device (a) to (c) are diagrams showing the movement of the flapper seen from the rear side of the device Explanatory drawing of conventional technology Explanatory drawing of conventional technology

Preferred embodiments of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following embodiments should be appropriately changed according to the configuration of the device to which the present invention is applied and various conditions. Therefore, it is not intended to limit the scope of the present invention only to them unless specifically stated otherwise.

First, referring to FIGS. 1 and 2, the overall configuration of an image forming apparatus to which the present invention is applied will be schematically described. FIG. 1 is a schematic cross-sectional view showing an example of an image forming apparatus. FIG. 2 is a schematic cross-sectional view of the image forming apparatus shown in FIG. 1 with the right door opened. Here, when the image forming apparatus shown in FIG. 1 is viewed from a direction orthogonal to the plane of FIG. 1, the front side of the plane of FIG. 1 is the front side of the plane, and the rear side of the plane of FIG.

As shown in FIG. 1, the image forming apparatus 100 includes an apparatus main body 101 having an image forming unit 11 for forming an image on a recording material P such as paper, and fixing an image on the recording material P removable from the apparatus main body 101. and a fixing device 30 . The apparatus main body 101 has a flapper 40 as a switching member for selectively switching a path (conveyance path) for guiding the recording material P. FIG. A flapper 40 as a switching member is rotatably provided on the apparatus main body 101 . The fixing device 30 in this embodiment is a unit detachably attached to the apparatus main body 101 . Of the insertion/removal directions Ya and Yb of the fixing device 30 with respect to the device main body 101, the removal direction is Ya and the insertion direction is Yb (see FIG. 2).

In the image forming section 11, process cartridges 11Y, 11M, 11C, and 11K having photosensitive drums are arranged along the intermediate transfer belt 11a. In the process cartridge 11Y, a yellow toner image is formed on the photosensitive drum and primarily transferred onto the intermediate transfer belt 11a. In the process cartridge 11M, a magenta toner image is formed on the photosensitive drum and is primarily transferred over the yellow toner image on the intermediate transfer belt 11a. In the process cartridges 11C and 11K, a cyan toner image and a black toner image are formed on the photosensitive drums, respectively, and are sequentially primary-transferred so as to overlap the toner image on the intermediate transfer belt 11a.

On the other hand, the recording material P fed from the paper feeding unit 10 waits in front of the transfer unit 12 and is sent to the transfer unit 12 in timing with the toner image on the intermediate transfer belt 11a.

The four-color toner images carried on the intermediate transfer belt 11a are conveyed to the transfer section 12, and collectively transferred onto the recording material P which is conveyed while being sandwiched by the transfer section 12 while being superimposed on the intermediate transfer belt 11a. Thereafter, the recording material P passes through the fixing device 30 so that the toner image is heat-fixed on the recording material P, and is discharged from the discharge rollers 13 in the case of single-sided printing only. When the paper is discharged from the paper discharge roller 13, the flapper 40 switches the conveying path toward the paper discharge roller 13 as indicated by the broken line in FIG. In the case of double-sided printing, the trailing edge of the recording material P reaches the reversing point B after the leading edge of the recording material P passes through the flapper 40 whose conveying path is switched in the direction of the reversing roller 14 as indicated by the solid line in FIG. The reversing roller 14 conveys the recording material P in the direction of the reversing path 141 until the recording material P is reached. Thereafter, the orientation of the flapper 40 is switched toward the double-sided conveying roller 15 by a switching mechanism, which will be described later. By reversing the rotation direction of the reversing roller 14 , the recording material P is switched back with the trailing end of the recording material P as the head, passes over the flapper 40 , and is conveyed toward the double-sided conveying roller 15 . Then, the recording material P passes through the double-sided conveying path 16, and passes through the image forming section 11, the transfer section 12, and the fixing device 30 again. The paper discharge roller 13 is provided downstream of the fixing device 30 in the recording material conveying direction, and serves as a discharge means for discharging the recording material. The reversing roller 14 is provided downstream of the fixing device 30 in the conveying direction of the recording material, and is reversing means for reversing and conveying the recording material by reversing the rotating direction.

Here, in this embodiment, the attitude of the flapper 40 when conveying the recording material P toward the double-sided conveying roller 15 and the attitude of the flapper 40 when conveying the recording material toward the discharge roller 13 are indicated by broken lines in FIG. are the same as shown in Therefore, it is not necessary to switch the orientation of the flapper 40 at this point. Therefore, the recording material P that has passed through the fixing device 30 reaches the flapper 40 and is ejected toward the ejection roller 13 .

Here, the right door unit 60 including the transfer section 12 and the double-sided conveying path 16 is configured to be able to open and close around the right door rotation center 61 with respect to the image forming apparatus main body 101 . As shown in FIG. 2, by opening the right door unit 60 with respect to the main body of the apparatus, it becomes possible to remove the recording material remaining around the transfer section when the paper jams. Furthermore, the fixing device 30 can be removed from the image forming apparatus main body 101 in the removal direction Ya, so that the recording material P caught in the fixing device 30 can be easily removed.

By the way, the operation panel 80 provides operation guidance to the user when, for example, a paper jam occurs, and sets various image forming apparatuses. The operation panel 80 is arranged on the right side of the sheet ejection reversing section including the sheet ejection roller 13 and the reversing roller 14, that is, above the right door unit 60, for the purpose of user visibility and efficient use of space. If the operation panel 80 rotates together with the right door unit 60 , the visibility is deteriorated. As a result, the sheet ejection reversing section including the sheet ejection roller 13 and the reversing roller 14 is also fixedly arranged in the image forming apparatus main body.

[Schematic Configuration of Fixing Device]
Next, the fixing device 30, which is a unit detachable from the main body of the image forming apparatus, will be described with reference to FIGS. 3, 4 and 5. FIG. FIG. 3 is a schematic diagram of a fixing device in the image forming apparatus. 4A and 4B are perspective views of the pressure application mechanism of the fixing device. FIG. 5 is a cross-sectional view of the pressure applying mechanism of the fixing device.

As shown in FIG. 3, the fixing device 30 has a heating film assembly 302 as a heating rotator and a pressing roller 303 as a pressurizing rotator that is pressed against the heating film assembly 302 . The fixing device 30 heats the recording material P having the toner image by means of the heating film assembly 302 and the pressure contact roller 303 and nips and conveys the recording material P for fixing. An inlet guide 317 for guiding the recording material to the nip portion is arranged upstream of the nip portion N between the heating film assembly 302 and the pressing roller 303 in the recording material conveying direction. A fixing ejection guide 310 and a fixing reversing guide 311 are arranged on the downstream side of the nip portion N in the recording material conveying direction. The fixing discharge guide 310 is a first guide member for guiding the recording material P from the nip portion N toward the discharge roller 13 . The fixation reversal guide 311 is a second guide member for guiding the recording material P that has been switched back toward the double-sided conveying roller 15 while guiding the recording material P from the nip portion toward the reversing roller 14 . The fixation reversal guide 311 is provided upstream of the fixation paper discharge guide 310 in the direction of mounting or inserting the fixing device into the apparatus main body (the direction of the arrow Yb in FIG. 2) and facing the fixing paper discharge guide 310 . A fixing reversal upper guide 312 is arranged on the opposite side of the fixing reversal guide 311 across the two-sided conveying path 16 .

<Pressure configuration>
As shown in FIGS. 4A and 4B, both ends of the pressure roller 303 are rotatably supported by bearings (not shown) attached to a fixing side plate 339 fixed inside the fixing device 30 . It is A heating film assembly 302 as a heating member is supported by a fixing side plate 339 so as to be movable in the pressing direction with the pressing roller 303 . A fixing nip portion is formed by pressing the film regulating member 337 of the heating film assembly 302 with pressure plates (parts of the pressure applying mechanism) 322 and 323 . One ends of the pressure plates 322 and 323 are hooked on holes 341 and 351 (FIG. 5) of support frames 324 and 325 attached to the fixing side plate 339 . A pressure spring (a part of the pressure application mechanism) 340 presses the film regulating member 337 while rotating the pressure plates 322 and 323 about the holes 341 and 351, and the support frames 324 and 325 and the pressure plates 322 and 323. is set between

Here, in general, in order to nip and convey the recording material P having a toner image while heating, it is necessary to apply a large pressure to the nip portion. If the user removes it, it is necessary to reduce the pressure at the nip.

Therefore, the fixing device 30 has a pressure changing mechanism that changes the pressure applied to the fixing nip portion. The pressure changing mechanism has cams 328 and 329 as cam members that act on the pressure applying mechanism, and the rotation of the cams 328 and 329 acts on pressure plates 322 and 323 that are part of the pressure applying mechanism. , the pressure applied to the fixing nip portion N can be reduced.

Cams 328 and 329 as cam members acting on the pressure application mechanism are fixed on both sides of a cam rotating shaft 350, and one side of the cam rotating shaft 350 has a gear 315 for transmitting drive to the rotating shaft. is doing.

It also has a gear 314 for driving the pressure contact roller 303 , and a driving force from a motor (not shown) as a driving source provided in the image forming apparatus main body 101 is transmitted to the gears 315 and 341 . is configured as follows.

As described above, in order to nip and convey the recording material P having the toner image while heating, it is necessary to apply a large pressure to the nip portion. As shown in FIG. 5, the distance L2 between the nip portion N and the rotation center of the pressure plates 322 and 323 and the distance L2 between the pressure spring 340 and the rotation center of the pressure plates 322 and 323 is greater than the distance L1 between the nip portion N and the pressure plates 322 and 323 in order to generate pressure efficiently. should be long (L2>L1). Furthermore, in order to effectively reduce the pressure in the nip portion N during paper jamming, it is necessary to further increase the distance L3 from the center of rotation of the pressure plates 322 and 323 to the contact positions of the cams 328 and 329 ( L3>L2).

That is, it becomes necessary to dispose the cam rotating shaft 350 of the cams 328 and 329 at a distance from the nip portion N.

<Cooling the edge of the heating film assembly>
Here, when the recording material P having a narrow width with respect to the length in the longitudinal direction of the heating film assembly 302 is continuously passed through, the area through which the recording material P of the heating film assembly 302 passes is always a continuous recording. Heat is taken away by the material P. However, since heat is accumulated in the non-paper passing area of the heating film assembly 302 through which the recording material P does not pass, it is necessary to cool it. For this reason, as shown in FIG. 6, the front cover 354 is provided with a front cover louver 354H, which is an air hole for cooling the non-sheet passing area of the heating film assembly 302. As shown in FIG.

Here, since the cam rotating shaft 350 needs to be arranged at a position that does not interfere with the air path for cooling the non-sheet-passing area of the heating film assembly 302, it is necessarily located in the upper left direction in FIG. should be placed in

The fixing paper discharge guide 310 described above is arranged so as to cover the cam rotation shaft 350 so that the recording material P advancing toward the paper discharge roller 13 is not caught.

<Flapper contact part>
FIG. 7 shows components provided in the fixing device 30 for striking the flapper 40 .

A flapper push-up portion 311R and an insertion link push-up portion 311F extending toward the cam rotating shaft 350 are provided at both ends of the fixing reversing guide 311 in the longitudinal direction. The flapper push-up portion 311R is provided on one side in the longitudinal direction (the rear side of the apparatus), pushes up the abutment portion 402 of the flapper 40 described later, and pushes the recording material P conveyed from the fixing nip portion toward the paper discharge roller 13. Positioned to direct the transport path. The insertion link push-up portion 311F is provided on the other side in the longitudinal direction (on the front side of the device) and arranged to push up a unit insertion link 90, which will be described later.

On the cam rotating shaft 350, a flapper link 360, which is rotatable by a driving source to be described later, is provided outside the flapper push-up portion 311R so as to orient the conveying path of the flapper 40 toward the reversing roller 14. .

[Detachment Mechanism of Fixing Device]
Next, referring to FIG. 8, a schematic configuration of a mechanism for attaching and detaching the fixing device 30 to and from the image forming apparatus main body 101 will be described.

The image forming apparatus main body 101 is provided with main body frame horizontal guide portions 112 and 122 as a pair of attachment/detachment guides for supporting the positioning pin 330 of the fixing device 30 . The body frame horizontal guide portions 112 and 122 are horizontally provided on the body frames 110 and 120 . The body frames 110 and 120 are horizontally provided with a fixing rail 114 that guides the guide portion 355 of the fixing device 30 in the same manner as the body frame horizontal guide portions 112 and 122 . The positioning pin 330 is guided by the body frame horizontal guide portions 112 and 122, and the guide portion 355 is similarly guided by the fixing rail 114, so that the fixing device 30 can be moved in the insertion/removal directions Ya and Yb while maintaining a fixed posture. becomes movable.

<Structure of output reversing section>
Next, FIG. 9 shows the arrangement of the ejected sheet reversing portion fixedly arranged in the image forming apparatus main body 101, and the fixing ejecting guide 310, the fixing reversing guide 311, and the fixing reversing upper guide 312 of the fixing device 30 which are arranged removably. show. 9 shows a state in which the fixing device 30 is attached to the image forming apparatus main body 101 as viewed from the front side of the apparatus, and a state in which the flapper 40 is switched to the position indicated by the dashed line in FIG. The position of the flapper 40 shown in FIG. 9 is a position for guiding the recording material that has passed through the fixing device toward the discharge roller, and a position for guiding the recording material transported by the reverse rotation of the reversing roller toward the double-sided transport roller. 14A shows a state in which the fixing device 30 is attached to the image forming apparatus main body 101 as viewed from the rear side of the apparatus, and a state in which the flapper 40 is switched to the position indicated by the solid line in FIG. The position of the flapper 40 shown in FIG. 14A is the position where the recording material that has passed through the fixing device is guided in the direction of the reversing roller. Note that FIG. 14A shows the entire fixing device 30 attached to the apparatus main body 101 .

A flapper 40 as a switching member is arranged on the discharge reversing guide 51 so as to be rotatable through a predetermined angle via a flapper rotating shaft 41 . The discharge reversing guide 51 is fixedly arranged on the discharge reversing frame 52 . The flapper 40 is constantly urged in the direction of arrow E shown in FIG. 9 around the flapper rotating shaft 41 by the urging force of an urging spring (urging member). In the process of attaching the fixing device to the main body of the image forming apparatus, the flapper abutting portion 402 provided on the device rear side of the flapper 40 abuts against the flapper push-up portion 311R of the fixing reversing guide 311. is rotated in the direction opposite to the direction of arrow E shown in FIG. Therefore, the attitude of the flapper 40 in the conveying path direction toward the discharge roller 13 is determined when the fixing device is attached to the main body of the image forming apparatus as shown in FIG. The flapper 40 at this time is in the position shown in FIG. 9, which is the first guide position indicated by the dashed line in FIG. Therefore, the recording material that has passed through the nip portion of the fixing device is ejected in the first direction through the first transport path between one surface of the flapper 40 at the first guide position and the fixing paper ejection guide 310 . It is guided toward the paper roller 13 .

The flapper 40 at the first guide position has its leading end portion 401 extending into the interior of the fixing device from the insertion/removal trajectory 310T at the highest point of the fixing/discharging guide 310 in the fixing device in the direction intersecting the insertion/removal directions Ya and Yb. It is in a state in which only the overlap amount T has entered. The amount of overlap T shown in FIG. 9 is such that the tip portion 401 of the flapper 40 positioned at the first guide position crosses the insertion/removal directions Ya, Yb from the insertion/removal trajectory 310T of the fixing device. It is the amount that penetrated inside.

At this time, the leading end portion 401 of the flapper 40 overlaps the fixing reversing guide 311 as shown in FIG. is set. In the process of attaching the fixing device to the main body of the image forming apparatus, the highest point of the fixing paper discharge guide 310 of the fixing device passes under the leading end portion 401 of the flapper 40 retracted to the retracted position described later. After that, as described above, the flapper push-up portion 311R of the fixing device abuts against the flapper abutment portion 402 . As a result, the flapper 40 at the retracted position is rotated, and the leading end 401 of the flapper 401 enters the interior of the fixing device by the overlap amount T from the insertion/extraction trajectory 310T at the highest point of the fixing/discharging guide 310 . When the fixing device is completely attached, the tip 401 of the flapper 40 overlaps the fixing reversing guide 311 as shown in FIG. Further, the fixation paper discharge guide 310 of the fixing device 30 is arranged so as to cover the cam rotating shaft 350 as described above.

On the other hand, the flapper 40 is switched in the direction of the reversing roller 14 by a solenoid 70, which will be described later, in a state in which the fixing device is attached to the main body of the image forming apparatus as shown in FIG. 14(a). At this time, the flapper 40 is switched to the second guide position indicated by the solid line in FIG. Therefore, the recording material that has passed through the nip portion of the fixing device passes through the second conveying path between the other surface of the flapper 40 at the second guide position and the fixation reversal guide 311, and the direction is different from the first direction. It is guided in the direction of the reversing roller 14, which is the second direction.

Further, the flapper 40 switched to the second guide position shown in FIG. 14(a) is further rotated in the direction opposite to the direction of arrow E shown in FIG. 9 compared to the first guide position shown in FIG. there is For this reason, the flapper 40 enters a state in which the leading end portion 401 is further intruded into the interior of the fixing device than in the first guide position. That is, the flapper 40 at the second guide position has its leading end portion 401 in the direction intersecting the insertion/removal directions Ya and Yb, which extends from the insertion/removal locus 310T at the highest point of the fixing/discharge guide 310 in the fixing device to the inside of the fixing device. It will be in a state in which it has entered by the overlap amount Tmax. The overlap amount Tmax shown in FIG. 14A is such that the flapper 40 is positioned at the solid line position shown in FIG. It is the amount that entered into the fixing device from the beginning. The relationship between the amount of penetration into the fixing device between the flapper 40 at the first guide position shown in FIG. 9 and the flapper 40 at the second guide position shown in FIG. 14A is T<Tmax. That is, the flapper 40 penetrates into the fixing device more at the second guiding position shown in FIG. 14A than at the first guiding position shown in FIG. The overlap amount Tmax is the maximum penetration amount of the flapper 40 .

FIG. 10 shows the link mechanism for rotating the flapper viewed from the back side of the image forming apparatus main body 101 . The link mechanism to be described below is a switching mechanism that selectively switches the flapper 40 in a state in which the tip portion 401 is inserted into the interior of the fixing device 30 attached to the apparatus main body 101 to a path (conveyance path) for guiding the recording material. is. The link mechanism is composed of a solenoid 70, a solenoid link 71, a flapper link 360, etc., which will be described later.

When the solenoid 70 fixedly arranged in the image forming apparatus main body 101 is attracted by an electric signal, the solenoid link 71 rotates, pushes down one end of the flapper link 360, and the flapper link tip 361 at the other end abuts the flapper. The part 402 is pushed up. As a result, the attitude of the flapper 40 in the conveying path direction toward the reversing roller 14 is determined.

At this point, the electric signal of the solenoid 70 is stopped to stop the suction, and the flapper 40 is returned to the paper transport path direction toward the paper discharge roller 13 by the biasing force of the biasing spring (not shown).

<Removing the fixing device>
Next, the process of removing the fixing device 30 from the image forming apparatus main body 101 is shown in FIGS. 11 and 14B. Note that FIG. 11 shows the fixing ejection guide 310 , the fixing reversing guide 311 , and the fixing reversing upper guide 312 of the fixing device 30 . FIG. 14B shows the entire fixing device 30 in the process of removing the fixing device 30 from the apparatus main body 101 .

As shown in FIGS. 11 and 14B , in the process of removing the fixing device 30 from the image forming apparatus main body 101 , the abutting portion 402 of the flapper 40 is released from the flapper push-up portion 311 R of the fixing reversing guide 311 . For this reason, the flapper 40 can rotate to an angle at which the flapper tip portion 401 does not overlap the fixing paper ejection guide 310 in the direction intersecting the insertion/removal direction Y. FIG.

Drive sources such as solenoids 70 and motors are generally arranged in the peripheral area of the electric board in order to minimize the length of the wires and to arrange them efficiently. That is, in this embodiment, since the electric board is arranged on the rear side of the image forming apparatus, the solenoid 70 is also arranged on the rear side of the apparatus. Therefore, it is required to make the solenoid 70 as small as possible in the rear side area of the device where the space is relatively narrow. In addition, since the attractive force of a solenoid generally varies depending on the number of turns of the built-in coil, it is necessary to reduce the required attractive force in order to reduce the size of the solenoid itself.

In this embodiment, in order to reduce the size of the solenoid 70 described above and to efficiently reduce the main body size, the flapper biasing force (arrow E direction force) is reduced. For this reason, the biasing spring is not set to an angle at which the flapper tip portion 401 does not overlap the fixing discharge guide 310 in the direction intersecting the insertion/removal direction Y, that is, the biasing force to an angle close to the horizontal.

A unit insertion link 90 as a retraction means is provided on the front side of the device main body 101 . The unit insertion link 90 is provided so as to contact or separate from the flapper 40 . The unit insertion link 90 is urged in a direction (arrow F direction in FIG. 12A) to retract the flapper 40 to the outside of the mounting area of the fixing device. The unit insertion link 90 is set to an angle such that when the fixing device 30 is pulled out from the apparatus main body 101 , the tip portion 401 of the flapper 40 does not overlap the fixing paper discharge guide 310 in the direction crossing the insertion/removal direction Y. sure to lift. That is, the unit insertion link 90 is a retracting means for retracting the flapper 40 to the outside of the mounting area of the fixing device in the apparatus main body in the process of removing the fixing device from the apparatus main body. The unit insertion link 90 is provided outside the recording material conveying area in the width direction orthogonal to the recording material conveying direction. Here, as shown in FIG. 14B, the mounting region of the fixing device is a region 30T from the insertion/extraction trajectory 310T at the highest point in the insertion/extraction direction Ya, Yb of the fixing/discharge guide 310 to the lower end of the fixing device. be. The outside of the mounting area for retracting the flapper 40 is the outside of this mounting area 30T. More specifically, the outside of the mounting area where the flapper 40 is retracted means the outside (upper side) of the insertion/extraction trajectory 310T at the highest point in the insertion/extraction direction Ya, Yb of the fixing paper ejection guide 310, as shown in FIG. 14(b). be. The flapper tip portion 401 of the flapper 40 is retracted to a position where it does not overlap the fixing paper discharge guide 310 in the direction intersecting the insertion/removal directions Ya and Yb.

FIG. 12A shows a perspective view around the unit insertion link 90 when the fixing device 30 is attached to the image forming apparatus main body 101. FIG. FIG. 12B shows a perspective view around the unit insertion link 90 arranged in front of the fixing reversing guide 311 at the position of the fixing device 30 in FIG. 11 in the process of pulling out the fixing device from the main body of the image forming apparatus. 15(a) and 16(a) show the unit insertion link in the process of pulling out the fixing device from the main body of the image forming apparatus. 15(b) to (c) and FIGS. 16(b) to (c) show the unit insertion link when the fixing device is attached to the image forming apparatus main body. 15(a) to (c) show the front side of the device, and FIGS. 16(a) to (c) show the rear side of the device. Here, the rear side of the device is one longitudinal side of the fixing reversing guide 311 shown in FIG. 7 where the flapper push-up portion 311R is provided. The device front side is the other side in the longitudinal direction of the fixing reversing guide 311 shown in FIG. 7 where the insertion link push-up portion 311F is provided.

As shown in FIGS. 12(a) and 12(b), the unit insertion link 90 is arranged so as to be rotatable within a predetermined angle range about the flapper rotating shaft 41, and is always biased in the direction of arrow F. The unit insertion link 90 is provided so as to contact or separate from the flapper 40 . Specifically, when the unit insertion link 90 is rotated, the insertion link abutment portion 91 of the unit insertion link 90 contacts or separates from the flapper retraction abutment portion 403 of the flapper 40 .

In the process of pulling out the fixing device from the main body of the image forming apparatus, as shown in FIG. 15A, the unit insertion link 90 is disengaged from the insertion link push-up portion 311F of the fixing device. As a result, the insertion link abutment portion 91 of the unit insertion link 90 abuts against the flapper evacuation abutment portion 403 of the flapper 40 by an urging force (not shown) to push up the flapper 40 . As a result, as shown in FIG. 14B, the flapper 40 is retracted to the outside of the mounting area 30T of the fixing device.

On the other hand, when the fixing device is attached to the main body of the image forming apparatus, as shown in FIGS. 15B and 15C, the unit insertion link 90 is pushed up by the insertion link push-up portion 311F of the fixing device. . As a result, the insertion link abutment portion 91 of the unit insertion link 90 is separated from the flapper evacuation abutment portion 403 of the flapper 40 .

Further, when the fixing device is attached to the main body of the apparatus, the flapper push-up portion 311R pushes up the abutment portion 402 of the flapper 40 as shown in FIG. 16(c). As a result, the flapper 40 is switched to the first guide position (broken line position shown in FIG. 1) for guiding the recording material that has passed through the nip portion of the fixing device toward the discharge roller. The recording material that has passed through the nip portion of the fixing device passes through a first conveying path between one surface of the flapper 40 at the first guide position and the fixing paper discharge guide 310, and then the paper discharge roller 13 in the first direction. be guided in the direction. At this time, as shown in FIG. 15(c), the insertion link abutment portion 91 of the unit insertion link 90 is separated from the flapper retraction abutment portion 403 of the flapper 40. As shown in FIG.

Further, when the fixing device is attached to the apparatus main body, the solenoid link 71 is rotated by the solenoid 70 (see FIG. 10) as shown in FIG. pushes up the abutting portion 402 of the flapper 40 . As a result, the flapper 40 is switched to the second guide position (solid line position shown in FIG. 1) for guiding the recording material that has passed through the nip portion of the fixing device toward the reversing roller. The recording material that has passed through the nip portion of the fixing device passes through the second conveying path between the other surface of the flapper 40 at the second guide position and the fixing and reversing guide 311 toward the reversing roller 14, which is the second direction. be guided. At this time, as shown in FIG. 15B, the insertion link abutment portion 91 of the unit insertion link 90 is separated from the flapper retraction abutment portion 403 of the flapper 40 .

Further, the recording material guided toward the reversing roller 14 is conveyed toward the reversing path 141 by the reversing roller 14 until the rear end thereof reaches the reversing point B shown in FIG. After the trailing edge of the recording material reaches the reversing point B, the flapper 40 is switched to the first guide position (the broken line position shown in FIG. 1). By reversing the rotation direction of the reversing roller 14 , the recording material P is reversely conveyed with the trailing end of the recording material P at the front, passes over the flapper 40 , and is conveyed toward the double-sided conveying roller 15 . At this time, as shown in FIG. 15(c), the insertion link abutment portion 91 of the unit insertion link 90 is separated from the flapper retraction abutment portion 403 of the flapper 40. As shown in FIG.

Further, in the process of removing the fixing device from the apparatus main body, as shown in FIG. 16A, the abutment portion 402 of the flapper 40 is released from the flapper push-up portion 311R of the fixing device. As a result, the flapper tip 401 of the flapper 40 can rotate with respect to the fixing paper discharge guide 310 to an angle that does not overlap in the direction intersecting the insertion/removal directions Ya and Yb (see FIG. 14B). Become. Further, in the process of removing the fixing device from the apparatus main body, as shown in FIG. 15A, the unit insertion link 90 is removed from the insertion link push-up portion 311F of the fixing device. As a result, the insertion link abutment portion 91 of the unit insertion link 90 abuts against the flapper evacuation abutment portion 403 of the flapper 40 by an urging force (not shown), and pushes up the rotatable flapper 40 . At this time, the flapper 40 is retracted to the outside of the mounting area 30T of the fixing device, as shown in FIG. 14(b). That is, the flapper tip portion 401 of the flapper 40 is retracted above the insertion/removal trajectory 310T at the highest point of the fixing/discharging guide 310 .

When the fixing device 30 is attached to the image forming apparatus main body 101 as shown in FIG. 12A, the fixing device side insertion link push-up portion 311F abuts on the apparatus main body side unit insertion link 90 . The insertion link push-up portion 311F pushes up the unit insertion link 90 in a direction opposite to the urging force in the arrow F direction. As a result, the insertion link abutment portion 91 of the unit insertion link 90 and the flapper retraction abutment portion 403 of the flapper 40 are separated from each other. is not transmitted. In addition, when the solenoid 70 is attracted and the attitude of the flapper 40 is changed in the direction of the reversing roller 14 in a state where the fixing device is attached to the main body of the apparatus, the insertion link abutment portion 91 and the flapper evacuation abutment portion 403 of the flapper 40 do not move. are placed apart from each other. Therefore, the biasing force acting on the unit insertion link 90 in the direction of arrow F is not transmitted to the flapper 40 .

As a result, the required attractive force of the solenoid 70 is not affected by the urging force acting on the unit insertion link 90 in the direction of the arrow F, so the size of the solenoid 70 can be reduced.

Next, as shown in FIG. 12B, the unit insertion link 90 is released from the insertion link push-up portion 311F in the process of pulling out the fixing device 30 from the apparatus main body. Then, the insertion link abutment portion 91 of the unit insertion link 90 abuts against the flapper retraction abutment portion 403 of the flapper 40 due to the biasing force acting on the unit insertion link 90 in the direction of the arrow F, and the flapper 40 moves in the direction of the arrow F. push up to Furthermore, the retraction posture of the flapper 40 is determined when the flapper 40 abuts against the sheet ejection reversing frame abutting portion 521 of the sheet ejection reversing frame 52 by the urging force.

FIG. 13 shows the retracted state of the flapper 40 , that is, the state in which the fixing device 30 is pulled out from the image forming apparatus main body 101 .

A flapper tip portion 401 of the flapper 40 is sufficiently retracted from an insertion/extraction trajectory 310T at the highest point in the insertion/extraction direction Y of the fixing/discharging guide 310 shown in FIG. That is, the flapper 40 is retracted outside the mounting area 30T (see FIG. 14B) of the fixing device 30 in the apparatus main body. Therefore, when the fixing device 30 is inserted or removed, the flapper tip portion 401 does not hit the fixing paper ejection guide 310, that is, the fixing device, so that insertion and removal can be performed without stress.

As described above, the flapper end portion 401 of the flapper 40 is retracted in the direction intersecting the insertion/removal direction Y in the process of pulling out the fixing device 30 from the main body of the apparatus. As a result, the size and weight of the image forming apparatus can be reduced, and the replacement of the fixing device and the operation at the time of paper jam (jam) can be performed smoothly.

In the above-described embodiment, the size of the entire image forming apparatus is efficiently suppressed by arranging the insertion link 90 on the front side of the apparatus where there is a relatively large space, but the present invention is not limited to this. For example, when there is an empty space in the device, the biasing force E of the flapper 40 may be increased and the solenoid 70 may be increased without providing the insertion link 90 .

Further, in the above-described embodiments, the fixing device was exemplified as a unit detachable from the main body of the image forming apparatus, but the present invention is not limited to this. Similar effects can be obtained by applying the present invention to another unit (such as a transport unit) detachably attachable to the apparatus main body and having a flapper having a positional relationship similar to that of the unit described above. can be done.

Further, in the above-described embodiments, the heating film assembly was exemplified as the heating rotating member of the fixing device, but the present invention is not limited to this. Other heating rotating bodies such as a heating roller containing a heating element such as a heater, or an endless belt may be used. Further, although the pressure contact roller 303 has been exemplified as the pressure rotating member of the fixing device, the present invention is not limited to this. Other pressurizing rotators such as an endless belt having a pressurizing portion for the heating rotator may be used.

Further, in the above-described embodiments, a printer is used as an example of the image forming apparatus, but the present invention is not limited to this. For example, other image forming apparatuses such as a copying machine and a facsimile machine, or other image forming apparatuses such as a multi-function machine combining these functions may be used. Similar effects can be obtained by applying the present invention to these image forming apparatuses.

N: Fixing nip portion 30: Fixing device 40: Flapper 41: Flapper rotating shaft 51: Discharge reversing guide 70: Solenoid 71: Solenoid link 90: Unit insertion link 91: Insertion link abutting portion 100: Image forming apparatus 101: Image forming apparatus main body 302 Heating film assembly 303 Pressure contact roller 310 Fixing paper ejection guide 311 Fixing reversal guide 311F Insertion link push-up section 311R Flapper push-up section 312 Fixing reversal upper guide 314 Gear 315 Gear 317 Entrance Guides 322, 323 Pressure plates 324, 325 Support frames 328, 329 Cam 330 Positioning pin 337 Film regulation member 339 Fixing side plate 340 Pressure springs 341, 351 Hole 350 Cam rotating shaft 354 Front cover 354H ... Front cover louver 360 ... Flapper link 401 ... Flapper tip portion 402 ... Flapper abutment portion 403 ... Flapper evacuation abutment portion

Claims (11)

an apparatus body having an image forming unit for forming an image on a recording material;
a unit detachably attached to the device main body ;
an image forming apparatus having a switching member rotatably provided in the apparatus main body for selectively switching a path for guiding a recording material in a state of entering the unit mounted in the apparatus main body. and
a retraction means provided in the apparatus main body for retracting the switching member to the outside of the mounting area of the unit in the process of removing the unit from the apparatus main body;
The retracting means is provided so as to be able to contact or separate from the switching member, and is urged in a direction to retract the switching member to the outside of the mounting area of the unit, so that the unit moves relative to the apparatus main body. is separated from the switching member against the urging force by abutting the unit when it is mounted on the switch,
In the process of removing the unit from the apparatus main body, the abutting state between the unit and the retracting means is released, so that the retracting means is brought into contact with the switching member by the biasing force that biases the retracting means. and the switching member is retracted to the outside of the mounting area of the unit. 2. The apparatus according to claim 1, wherein the retracting means is brought into contact with the unit in the process of attaching the unit to the apparatus main body, and is separated from the switching member against an urging force. Image forming device. 3. The retracting means according to claim 1 , wherein the retracting means is kept away from the switching member even when the switching member is switched in a state where the unit is attached to the apparatus main body. Image forming device. 2. A switching mechanism for selectively switching the switching member to a path for guiding a recording material when the unit is attached to the apparatus main body is provided separately from the retracting means. 4. The image forming apparatus according to any one of 3 . 5. The apparatus according to any one of claims 1 to 4 , wherein the image forming section of the apparatus main body forms a toner image on a recording material, and the unit is a fixing device that fixes the toner image on the recording material. The image forming apparatus according to . 6. The image forming apparatus according to claim 5 , wherein the fixing device performs fixing by holding and conveying a recording material having a toner image while heating the recording material with a heating rotator and a pressurizing rotator. The switching member has a first guide position at which the recording material passing between the heating rotor and the pressure rotor is guided in a first direction, and a second guide position at which the recording material is guided in a direction different from the first direction. 7. The image forming apparatus according to claim 6 , wherein the image forming apparatus can be switched to a second guide position for guiding in two directions. a discharge unit provided downstream of the fixing device in the direction in which the recording material is conveyed and discharging the recording material;
a reversing unit provided on the downstream side of the fixing device in the conveying direction of the recording material and reversing and conveying the recording material by reversing the rotation direction;
The recording material passing between the heating rotor and the pressurizing rotor is guided in the direction of the discharging means by the switching member switched to the first guide position, and switched to the second guide position. 8. The image forming apparatus according to claim 7 , wherein the image forming apparatus is guided toward the reversing means by a member. When images are formed on both sides of the recording material, the recording material passing between the heating rotator and the pressure rotator is guided toward the reversing means by the switching member switched to the second guide position. 9. The image forming apparatus according to claim 8 , wherein thereafter, the switching member is switched to the first guide position, and the direction of rotation of the reversing means is reversed, thereby again guiding the sheet toward the image forming section. Device. The tip of the switching member enters the inside of the fixing device in the process of attaching the fixing device to the apparatus main body, and when the fixing device is attached to the apparatus main body, the switching member moves from the first guide position to the switching member. 10. The image forming apparatus according to claim 7 , wherein switching to the second guide position maximizes the amount of penetration of the leading edge into the interior of the fixing device. The switching member is urged in a direction to retreat from the mounting area of the unit,
11. The method according to claim 10, wherein the switching member is brought into contact with the unit in the process of attaching the unit to the apparatus main body, and is moved to the first guide position against an urging force. The described image forming apparatus .

Images