JP6589507B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to drying and heating of paper in an image forming apparatus such as a copying machine or a laser printer.

  A fixing device used in an electrophotographic image forming apparatus forms a toner image on a sheet by heating and pressurizing a nip portion. This type of fixing device includes a heating member and a pressure roller, and both members are configured to be pressed to form a fixing nip. The recording sheet on which the toner image has been transferred, which has been conveyed to the fixing device, is heated while being pressed against the peripheral surface of the heating roller by the pressure roller at the fixing nip, and the toner image is thermally fixed on the recording sheet.

  In such heat fixing, since there is a temperature difference between the heating member and the pressure roller, when the recording sheet passes through the fixing nip, the front and back of the recording sheet (the surface on the heating member side and the pressure roller side) Temperature difference occurs on the back surface of the substrate. Specifically, the temperature of the surface of the recording sheet that contacts the heating roller is higher than the temperature of the back surface that contacts the pressure roller. As a result, after passing through the fixing nip, a large amount of moisture contained in the recording sheet evaporates from the surface, and the amount of moisture transferred to the surface increases. Therefore, the surface of the recording sheet has a higher moisture content than the back surface, and as a result, the elongation of the paper fibers on the front surface is larger than that on the back surface, causing the recording sheet to curl to the back side (hereinafter referred to as “back curl”). ") Occurs.

  Recently, from the viewpoint of energy saving / warming up, a fixing device has been developed that has a heating member with a low heat capacity and a high temperature rise. In such a fixing device, since the paper can be passed before the pressure roller side is warmed, the temperature difference between the heating member and the pressure roller is larger, and the temperature difference between the front and back of the paper at the time of fixing is larger. Prone. Therefore, the back curl generated by the fixing device is increasing. By discharging in a state where the back curl is large, there arises a problem that a specified number of sheets cannot be stacked on the discharge tray or the stacking itself on the discharge tray is disturbed. Further, the curled paper causes a conveyance failure due to catching at a transfer portion between the conveyance path and the finisher and the like, and also causes a paper alignment failure on the paper discharge tray.

  As a means for solving this problem, a decurling technique for correcting curl is already known. For example, Patent Document 1 is a technique for correcting paper curl by pressing the paper against a guide member. In the image forming apparatus described in Patent Document 1, a first transport roller is disposed on the downstream side of the fixing unit, and a second transport roller is disposed on the downstream side thereof. In addition, a guide member that curves in a direction opposite to the curl direction of the paper is provided in the transport path from the first transport roller to the second transport roller. The sheet conveyance speed by the second conveyance roller is set to a value larger than the sheet conveyance speed by the first conveyance roller. As a result, the sheet is conveyed while being pressed against the guide member curved in the direction opposite to the curl direction of the sheet, and the curl of the sheet is corrected.

  Further, Patent Document 2 discloses a technique in which a guide member that conveys a sheet discharged from a pair of rollers immediately after the pair of roller members on the downstream side of the fixing device is bent as the back curl correction means. . As a result, it can be corrected by bending in a direction opposite to the curl generated by fixing. Further, in Patent Document 3, a guide member is movably disposed between the fixing nip and the discharge nip so as to be movable in contact with the back side of the paper and bent in the direction opposite to the curl generated by fixing, and the contact force is changed by the stiffness of the paper. The configuration is disclosed.

  Further, Patent Documents 3 and 4 also disclose decal technology. These patent documents disclose a configuration in which the position of the guide plate is changed according to the size of the curl. However, there remains a problem with space saving.

In the conventional decal technique described above, the following problems occur.
In the case of Patent Documents 1 and 2, since curling is always forced in the reverse direction by the guide member, for example, in the case of cardboard feeding,
(1) In the fixing device, since the back curl in which the sheet is curled on the back surface does not occur, when the guide plate is always in the first position, the guide plate is reversed and the face curl is reversed.
(2) Since the contact force between the guide plate and the paper is strong, the guide member causes damage (scratches) to the back side of the paper and wear of the guide member.
(3) Since the paper rigidity is high, when the tip comes out of the roller pair and the tip comes into contact with the guide member, the tip is bent, which causes problems such as difficulty in stabilizing the conveyance.

  In the technology according to Patent Document 3, the guide member that deforms the paper in a corrective manner can be moved in the retracting direction by the stiffness of the paper, so that the contact pressure between the paper and the guide member increases when the thick paper is passed. It can be said that the above-mentioned problems (1) to (3) can be avoided by retracting the guide member and adjusting the contact pressure.

  However, even if the guide member moves to the final retracted position, the guide member position is determined by the stiffness of the paper, so that the guide member and the paper are conveyed while being in contact with each other. When double-sided paper is passed, there is an image of the first surface on the back surface of the sheet that comes into contact with the guide member, and this image surface and the guide member come into contact with each other. Immediately after fixing on the second side, the image on the back side is not at a temperature at which the toner completely melts, but the toner image that has received heat comes into contact with the guide member. In this case, gloss unevenness (difference in gloss from a portion not in contact with the guide member) is likely to occur even with light contact. This uneven glossiness cannot be completely prevented or avoided only by controlling the contact pressure between the guide member and the paper with only the stiffness of the paper.

  Further, there is a problem that the positional relationship between the fixing nip and the exit nip with the guide plate is restricted, and the degree of freedom in layout is small. However, the conventional fixing exit guide plate is not comb-shaped at the delivery portion, and therefore has a problem that it does not save space.

  Generally, a conveyance path branching unit that switches the conveyance direction of the sheet after the fixing device is provided in the vicinity of the guide member. In that case, there is a problem that an event that gives an unpleasant impression to the user, such as an operation sound resonating continuously, may occur depending on how to take timings when they operate. Further, in the configuration in which the branching claw for decurling and the fixing exit roller are integrated with the fixing device, there is a problem that when the jam occurs in the vicinity of fixing, the visibility of the paper and the jam processing property are poor.

  In the technique according to Patent Document 5, in order to improve the visibility and jam handling of jammed paper, the paper conveyance path may be exposed in the range from the paper feeding unit to the front of the fixing unit by providing an opening / closing unit. Possible configurations are disclosed. However, although the visibility and jam handling of jammed paper can be improved, the problem of poor paper visibility and jam handling when a jam occurs in the vicinity of fixing cannot be solved.

  In the technique according to Patent Document 6, in order to correct paper curl, a configuration is disclosed in which when the paper comes into contact with the decurling member, the decurling member moves so as to bite into the paper surface to curl the paper. However, there is a problem that the uncurled part is decurled and curled. That is, since the decurling means always forcibly curls in the reverse direction by the guide member, for example, when curling only the front end of the paper, the rear end is curled in the reverse direction. In addition, when only the front and rear ends are curled, there is a problem that the middle part is curled in the opposite direction. Specifically, for example, when the A3 paper is passed, the heat of the fixing roller is taken away by the paper while the paper is passed, so the temperature is high at the leading edge of the paper and the temperature is low at the trailing edge. Tends to increase curl.

  In order to solve the above-described conventional problems, the present invention operates the driving means for driving the guide member and the conveyance path switching means to be substantially the same, thereby preventing the generation of unpleasant operating noise. The object is to provide a device.

The image forming apparatus of the present invention, after transferring the image formed by the image forming unit onto the recording medium, and a fixing device for fixing the image on the recording medium, the recording medium processed by the fixing device image A paper discharge device that discharges outside the forming device, a reversing device that reverses the recording medium processed by the fixing device, and a double-side device that transports the recording medium reversed by the reversing device into the image forming device again. And an image forming apparatus having a side cover that opens and closes the side surface of the apparatus main body integrated with the double-sided device, on the downstream side of the fixing device in the recording medium conveyance direction and on the upstream side of the sheet conveyance path branching unit, A guide member for guiding the recording medium discharged from the auxiliary conveyance roller member immediately after the auxiliary conveyance roller member; Driving means movable in contact with the recording medium and movable to a first position where the angle of the recording medium discharged from the auxiliary conveyance roller member is changed and a second position where the angle of the recording medium is not changed. And the double-sided device has the guide member .

According to the present invention, by opening and closing the side cover, it is possible to expose the paper conveyance path on the side surface of the main body where the paper jam has occurred, and the paper visibility is improved. Processability is improved.

1 is a diagram for describing an overall configuration and operation of an image forming apparatus according to an embodiment of the present invention. It is a figure for demonstrating the curl correction mechanism and fixing device which concern on one Embodiment of this invention. It is a figure for demonstrating the curl correction mechanism and fixing device which concern on one Embodiment of this invention. It is a figure which shows a guide member / branching member position. It is a figure which shows a guide member / branching member position. It is a figure which shows a guide member / branching member position. It is a figure which shows a guide member / branching member position. It is a figure shown about the drive of a guide member. It is a figure shown about the drive of a guide member. It is a figure shown about the drive of a guide member. It is a figure shown about the drive of a guide member. It is a figure shown about the drive of a guide member. It is a figure shown about the drive of a branch member. It is a figure which shows the conveyance surface and pressure side separation conveyance member which looked at the principal part of Embodiment 2 of this invention from the X view of FIG. It is a figure substantially the same as FIG. It is a figure which shows the drive means for moving a guide member. It is a figure shown about the drive of a guide member. It is a figure which shows the drive means for moving a guide member. It is a figure for demonstrating the structure of a fixing exit guide plate and a paper discharge branch claw. It is a figure which shows the case (B)-(D) when arrange | positioning spaced apart with a gap (A) and the case where it arrange | positions so that the front-end | tip of a guide member may overlap with a drive roller. It is a figure which compares and shows the case where the front-end | tip of a guide member overlaps with a drive roller, and the case where the front-end | tip of a guide member is arrange | positioned with a certain gap from the rubber outer diameter of a drive roller. It is a figure which shows the arrangement | positioning with respect to the pair of a conveyance auxiliary | assistant roller member when the front-end | tip of a guide member overlaps with a drive roller, and arrange | positions apart with a gap. It is a figure which shows the drive structure by the solenoid of several decurler claws (claw-shaped rib) which concerns on Embodiment 3 of this invention. It is a figure which shows the method of fixing the angle of a branch member. It is a figure for demonstrating the structural example of the drive structure by a rotary solenoid and an electromagnetic clutch for several branch members. It is a principal part enlarged view of FIG. It is a figure which shows the drive structure by the solenoid of several decurler claws (claw-shaped rib) which concerns on Embodiment 4 of this invention. It is a principal part enlarged view of FIG. It is a figure for demonstrating the double-sided unit which has the guide member, the drive roller, and the pressure side separation conveyance member (conventional example). It is a figure for demonstrating the double-sided unit which has the guide member which concerns on Embodiment 4 of this invention, a drive roller, and a pressure side separation conveyance member. It is a principal part enlarged view which concerns on Embodiment 4 of this invention. It is a perspective view similarly. FIG. 6 is a diagram illustrating a decurled state of an end portion of a sheet.

<Embodiment 1>
First, an overall configuration and operation of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG.
The image forming apparatus shown in FIG. 1 is a color laser printer, and four image forming units 4Y, 4M, 4C, and 4K are provided in the center of the apparatus main body 1. Each of the image forming units 4Y, 4M, 4C, and 4K contains developers of different colors of yellow (Y), magenta (M), cyan (C), and black (K) corresponding to the color separation components of the color image. The configuration is the same except that.

  Specifically, each of the image forming units 4Y, 4M, 4C, and 4K has a drum-shaped photoconductor 5 as a latent image carrier, a charging device 6 that charges the surface of the photoconductor 5, and a surface of the photoconductor 5. A developing device 7 for supplying toner and a cleaning device 8 for cleaning the surface of the photoreceptor 5 are provided. In FIG. 1, only the photoconductor 5, the charging device 6, the developing device 7, and the cleaning device 8 included in the black image forming unit 4 </ b> K are denoted by reference numerals. In the other image forming units 4 </ b> Y, 4 </ b> M, and 4 </ b> C, The reference numerals are omitted.

  Under the image forming units 4Y, 4M, 4C, and 4K, an exposure device 9 that exposes the surface of the photoreceptor 5 is disposed. The exposure device 9 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of each photoconductor 5 with laser light based on image data. A transfer device 3 is disposed above the image forming units 4Y, 4M, 4C, and 4K. The transfer device 3 includes an intermediate transfer belt 30 as an intermediate transfer member, four primary transfer rollers 31 as primary transfer means, a secondary transfer roller 36 as secondary transfer means, a secondary transfer backup roller 32, A cleaning backup roller 33, a tension roller 34, and a belt cleaning device 35 are provided.

  The intermediate transfer belt 30 is an endless belt and is stretched by a secondary transfer backup roller 32, a cleaning backup roller 33, and a tension roller 34. Here, by rotating the secondary transfer backup roller 32, the intermediate transfer belt 30 runs (rotates) in the direction indicated by the arrow in the figure. Each of the four primary transfer rollers 31 sandwiches the intermediate transfer belt 30 with each photoconductor 5 to form a primary transfer nip. Each primary transfer roller 31 is connected to a power source, and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to each primary transfer roller 31.

  The secondary transfer roller 36 sandwiches the intermediate transfer belt 30 with the secondary transfer backup roller 32 to form a secondary transfer nip. Similarly to the primary transfer roller 31, a power source is also connected to the secondary transfer roller 36, and a predetermined DC voltage (DC) and / or AC voltage (AC) is applied to the secondary transfer roller 36. It is like that.

  The belt cleaning device 35 includes a cleaning brush and a cleaning blade disposed so as to contact the intermediate transfer belt 30. The waste toner collected by the belt cleaning device 35 is accommodated in a waste toner container via a waste toner transfer hose.

  A bottle container 2 is provided in the upper part of the apparatus main body 1, and four toner bottles 2Y, 2M, 2C, and 2K that store replenishing toner are detachably attached to the bottle container 2. Yes. Toner is supplied from each toner bottle 2Y, 2M, 2C, 2K to each developing device 7 via a supply path provided between each toner bottle 2Y, 2M, 2C, 2K and each developing device 7. A lower part of the apparatus main body 1 is provided with a paper feed tray 10 that stores paper P as a recording medium, a paper feed roller 11 that carries the paper P out of the paper feed tray 10, and the like. In addition to plain paper, the recording medium includes cardboard, postcard, envelope, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheet, and the like. A manual paper feed mechanism may be provided.

  In the apparatus main body 1, a conveyance path R is provided for discharging the paper P from the paper feed tray 10 through the secondary transfer nip and out of the apparatus. In the transport path R, a pair of registration rollers 12 serving as timing rollers for transporting the paper P to the secondary transfer nip at a transport timing is disposed upstream of the position of the secondary transfer roller 36 in the paper transport direction. ing.

  Further, a fixing device 20 for fixing the unfixed image transferred onto the paper P is disposed downstream of the position of the secondary transfer roller 36 in the paper transport direction. Further, a pair of paper discharge rollers 13 for discharging the paper P to the outside of the apparatus is provided downstream of the fixing device 20 in the paper conveyance direction of the conveyance path R. Further, a discharge tray 14 for stocking the paper P discharged outside the apparatus is provided on the upper surface of the apparatus main body 1.

Next, the basic operation of the color laser printer according to this embodiment will be described with reference to FIG.
When the image forming operation is started, the respective photoconductors 5 in the respective image forming units 4Y, 4M, 4C, and 4K are rotationally driven clockwise in the drawing, and the surface of each photoconductor 5 is set to a predetermined polarity by the charging device 6. Uniformly charged. The surface of each charged photoconductor 5 is irradiated with laser light from the exposure device 9 to form an electrostatic latent image on the surface of each photoconductor 5. At this time, the image information to be exposed on each photoconductor 5 is monochromatic image information obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black. In this way, toner is supplied to each electrostatic latent image formed on each photoconductor 5 by each developing device 7, whereby the electrostatic latent image is visualized (visualized) as a toner image. .

  When the image forming operation is started, the secondary transfer backup roller 32 is driven to rotate counterclockwise in the figure, and the intermediate transfer belt 30 is caused to run in the direction indicated by the arrow in the figure. Further, by applying a constant voltage having a polarity opposite to the toner charging polarity or a voltage controlled by a constant current to each primary transfer roller 31, the primary transfer nip between each primary transfer roller 31 and each photoreceptor 5 is applied. A transfer electric field is formed.

  Thereafter, when each color toner image on the photoconductor 5 reaches the primary transfer nip as each photoconductor 5 rotates, the toner image on each photoconductor 5 is generated by the transfer electric field formed in the primary transfer nip. Are sequentially superimposed and transferred onto the intermediate transfer belt 30. Thus, a full color toner image is carried on the surface of the intermediate transfer belt 30. Further, the toner on each photoconductor 5 that could not be transferred to the intermediate transfer belt 30 is removed by the cleaning device 8. Then, the surface of each photoconductor 5 is neutralized by the neutralization device, and the surface potential is initialized. In the lower part of the printer, the paper feed roller 11 starts to rotate, and the paper P is sent out from the paper feed tray 10 to the transport path R. The paper P sent to the transport path R is temporarily stopped by the registration rollers 12.

  Thereafter, rotation of the registration roller 12 is started at a predetermined timing, and the paper P is conveyed to the secondary transfer nip in accordance with the timing at which the toner image on the intermediate transfer belt 30 reaches the secondary transfer nip. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 30 is applied to the secondary transfer roller 36, thereby forming a transfer electric field in the secondary transfer nip. . Then, the toner images on the intermediate transfer belt 30 are collectively transferred onto the paper P by this transfer electric field. At this time, the residual toner on the intermediate transfer belt 30 that could not be transferred onto the paper P is removed by the belt cleaning device 35 and conveyed to a waste toner container.

  Thereafter, the paper P is conveyed to the fixing device 20, and the toner image on the paper P is fixed to the paper P by the fixing device 20. The paper P conveyed from the fixing device is guided in the discharge direction and the refeeding direction via the branching member 15 for switching the paper discharge path to the outside of the apparatus and the double-side reversal path.

  In the single-sided paper passing mode, the branching member 15 is opened, and a pair of paper discharge rollers 13 for discharging discharges the paper P discharged outside the apparatus provided on the upper surface of the apparatus main body 1 for stocking. It is discharged to the paper tray 14. In the double-sided sheet passing mode, the branching member 15 is closed in the direction of the arrow, so that the sheet P after the first side fixing is guided to the double-sided reverse path. The paper P guided to the double-side reversal path is switched back by the pair of reverse rollers 16, transported to the double-side unit 17, transported again to the pair of registration rollers 12, and re-feeded. Similarly to the above, the second side image is printed on the back side of the paper. Then, the paper P is discharged out of the apparatus by the paper discharge roller 13 and stocked on the paper discharge tray 14.

  The above description is an image forming operation when a full-color image is formed on the paper P. A single-color image can be formed using any one of the four image forming units 4Y, 4M, 4C, and 4K. It is also possible to form a two-color or three-color image using two or three image forming units.

With reference to FIG. 2, a curl correction mechanism and a fixing device according to an embodiment of the present invention will be described in detail.
FIG. 2 is a cross-sectional view of the curl correction mechanism and the fixing device according to the present embodiment. As shown in FIG. 2, the fixing device 20 is used for fixing the transferred toner image carried on the paper P by melting and infiltrating it with heat and pressure, and while being heated as shown in FIG. A fixing belt 21 having a rotatable flexibility is provided.

In addition to the fixing belt 21, the fixing device 20 is a pressure that is a counter rotating body that forms a nip portion N by applying pressure to the fixing belt 21 in contact with the fixing belt 21. A roller 22 is provided. Inside the fixing belt 21, a heater 23 including a plurality of halogen lamps 23 a and 23 b for heating the fixing belt 21 at a place other than the nip portion N is provided.
Inside the fixing belt 21, a nip forming member 24 that is a base member for forming a nip disposed inside the fixing belt 21, a stay 25 that supports the nip forming member 24, and light emitted from the heater 23. Is provided on the fixing belt 21.

  Although not shown in detail, the nip forming member 24 that is a base member for forming a nip has a sliding sheet (low friction sheet) wound with a base pad. In the nip forming member 24 shown in the drawing, the shape of the nip portion N is flat, but is not limited to this shape. For example, when it is formed in a concave shape along the peripheral surface of the pressure roller 22, the leading edge of the paper P passing through the nip portion N is close to the pressure roller 22, so that the separation from the fixing belt 21 is improved. There are advantages.

  The temperature of the fixing belt 21 is detected by a temperature sensor 27 provided on the side where the paper P enters the nip portion, and used for feedback processing of the heater 23. In FIG. 2, an arrow F indicates the conveyance direction of the paper P. The fixing belt 21 is an endless belt formed in a thin and flexible sleeve shape, and is composed of a base material and a release layer located on the surface thereof. For the substrate, a metal material such as nickel or ASUS or a resin material such as polyimide is used. For the release layer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), or the like having releasability with respect to the toner is used.

  The pressure roller 22 includes a cored bar 22a, an elastic layer 22b made of foamable silicone rubber, silicone rubber, or fluororubber provided on the surface of the cored bar 22a, and PFA provided on the surface of the elastic layer 22b. It is constituted by a release layer 22c made of PTFE or the like. The pressure roller 22 is pressed toward the fixing belt 21 by a pressure unit (not shown) and is in contact with the nip forming member 24 as a base member in contact with the fixing belt 21. At the place where the pressure roller 22 and the fixing belt 21 contact each other, the elastic layer 22b of the pressure roller 22 is crushed so that pressure is applied to the fixing belt 21 and the nip forming member 24 has a predetermined width. The nip portion N is secured.

  The pressure roller 22 is configured to be rotationally driven by a drive source such as a motor (not shown) provided in the apparatus main body 1. When the pressure roller 22 is rotationally driven, the driving force is transmitted to the fixing belt 21 at the nip portion N, and the fixing belt 21 is driven to rotate.

  In the configuration shown in FIG. 2, the pressure roller 22 is a solid roller, but may be a hollow roller. In that case, a heating source such as a halogen heater using radiant heat may be disposed inside the pressure roller 22. In addition, when the elastic layer 22b is not provided, the heat capacity is reduced and the fixability is improved. However, when the unfixed toner is crushed and fixed, minute irregularities on the belt surface are transferred to the image and the solid portion of the image is glossy. Unevenness may occur. In order to prevent this, it is desirable to provide an elastic layer having a thickness of 100 μm or more. Aluminum, iron, stainless steel, or the like can be selected as the pipe-shaped metal used for the hollow roller. When providing a heat source in the pressure roller 22, in order to prevent the support from being heated by radiant heat from the heat source, a heat insulating layer is provided on the support surface or a heat ray reflecting surface is provided by mirror treatment. Is desirable. The heat source in this case is not limited to the halogen heater described above, and an IH heater, a resistance heating element, or a carbon heater can also be used.

  In the case of the fixing device 20 described above, since the heating member having a low heat capacity is directly heated, the temperature rises very quickly. Therefore, although there is an advantage that the first print can be made faster, from the viewpoint of curling the paper P, the pressure roller is fixed before it is sufficiently warmed, so that the back curl due to the temperature difference between the front and back is very large.

  Further, on the exit side of the sheet P of the fixing device 20, a separation transport mechanism is provided that separates the sheet P that has passed through the nip portion in the vicinity of the nip portion and guides the sheet P toward the sheet discharge portion in the discharge direction. The separation / conveying mechanism includes a belt-side separation / conveying member 201 having a tip close to the fixing belt 21 side on the downstream side in the moving direction of the sheet P moving from the nip portion, and an additive having a tip close to the pressure roller 22 side. And a pressure-side separation / conveyance member 202.

  The belt-side separating / conveying member 201 is provided to peel off the sticky paper P that adheres to the fixing belt 21 from the fixing belt 21. For this reason, metal is used so as to obtain an accuracy capable of positioning the stuck paper P at a close position where the paper P can be lifted from the surface of the fixing belt 21. The pressure-side separating / conveying member 202 is made of a resin molded product, and a support rod 202A provided in a part thereof is rotatably supported on the housing side (not shown) so as to face the pressure roller 22. The swinging end that swings can be swung so as to be able to come into contact with and separate from the pressure roller 22. Further, the pressure-side separating and conveying member 202 swings with respect to the pressure roller 22, for example, swings away from the pressure roller 22 when the jammed paper P is removed from the nip portion N. A space for inserting a hand into the nip portion N can be created. As a result, the paper P can be pulled out.

  On the downstream side of the pressure-side separation / conveyance member 202, a pair of conveyance auxiliary roller members including a driving roller 204 supported by the pressure-side separation / conveyance member 202 and a driven roller 203 supported by the holder 207 are disposed. The driving roller 204 is made of a solid rubber material having a high coefficient of friction made of a cored bar and silicon, EPDM, urethane, fluororubber or the like provided on the surface of the cored bar so as to obtain a sheet conveying force. The driven roller 203 has a structure in which a hollow pipe-shaped metal surface is covered with a low μ tube (thickness 30 to 300 μm) such as PFA, ETFA, FEP or the like. The reason for the hollow pipe-like metal is to reduce the heat capacity and prevent the water vapor generated by evaporation from the paper during fixing from adhering to the driven roller 203 side, so that the heat from the fixing belt 21 is immediately heated. Because. The reason why the low μ tube is arranged on the surface is that a small amount of toner that has not melted after fixing is difficult to adhere and does not accumulate even if it adheres (the driven roller 203 side has an image surface). Since it conveys while always contacting the side, it has the above-described configuration). By pressing the holder holding the driven roller 203 with a spring (not shown), the driving roller 204 and the driven roller 203 come into contact with each other to form a nip, thereby enabling paper conveyance. A movable guide member 205 for guiding the paper discharged from the pair of rollers 203 and 204 is provided immediately downstream of the pair of transport rollers 203 and 204. The guide member 205 is configured to be movable in two stages: the position shown in FIG. 2 and the position shown in FIG.

  When the guide member 205 is disposed at the position shown in FIG. 2, the direction of the paper ejected from the pair of transport rollers 203 and 204 (perpendicular to the line connecting the centers of the pair of rollers 203 and 204). And place it at a position that closes the route. As a result, the leading edge of the paper comes into contact with the guide member 205 at an angle θ, and then the paper is conveyed while being pressed against the guide member 205 by the conveying force of the conveying roller. Finally, the sheet can be bent to the opposite side of the back curl by conveying the sheet with an angle θ1 from the conveyance roller nip. By using such a conveyance path, the paper that has come out of the guide member 205 can be improved by improving the back curl generated in the fixing device 20 and discharged.

  However, since the paper back surface and the guide member 205 are positively brought into contact with each other, the conveyance resistance is large and stress is applied to the paper. For this reason, when transporting strong thick paper or the like, contact traces with the guide member 205 are likely to occur on the back surface of the paper, and the guide member 205 itself is likely to be worn away. In addition, when the second surface is passed in the duplex paper passing mode, the surface on which the image is present (first surface) and the guide member 205 are in contact with each other, and image blurring and gloss streaks are likely to occur. Immediately after leaving the fixing device 20, the first image on the back surface is also heated again while passing through the nip portion while fixing the second image surface. When the outermost surface of the toner is rubbed strongly in a warmed state, it tends to peel off or change its gloss.

  On the other hand, when the guide member 205 is disposed at the position shown in FIG. 3, the guide member 205 is disposed at a position where the guide member 205 is retracted with respect to the direction of the sheet discharged from the pair of conveyance auxiliary roller members, and is actively applied to the paper. It is configured not to touch. The direction of the discharged paper is perpendicular to the line connecting the centers of the pair of conveyance auxiliary roller members. In this case, the back curl of the paper P during conveyance cannot be corrected, but no stress is applied to the paper P. Therefore, as described above, scratches, abrasion, image blurring, gloss streaks, etc. do not occur on the back surface of the paper P.

In the present embodiment, the curling correction and the image blurring are not made compatible at the position of one guide member 205, but the position of the guide member 205 is driven by the driving means as will be described later in accordance with each paper passing mode. The position is switched to the position shown in FIG.
Specifically, the guide member 205 and the branching member 15 are movably arranged as follows to support each paper passing mode [in the single-sided paper passing mode]
Paper thickness of 160 g / m ² or less: guide member / branch member position in FIG. 4A Thick paper more than that: guide member / branch member position in FIG. 4B [during double-sided sheet feeding mode]
When passing the first side: Guide member / branching member position of FIG. 4C When passing the second side: Guide member / branching member position of FIG. 4D In the duplex mode, the guide member 205 for both the first side and the second side is: The branching member 15 that is arranged in the open position and switches between a path for discharging the sheet to the outside of the apparatus and a double-sided reversing path is moved and arranged. As a result, the paper P is guided to the reverse re-feed conveyance path after the first side fixing, and to the discharge path after the second side fixing.

Next, the operation timing of the guide member 205 and the branch member 15 will be described. As an example, a description will be given of the operation from the single-sided paper passing (curl correction) shown in FIG. 4A to the double-sided paper passing (first side) shown in FIG. 4C.
When operating from single-sided paper passing (curl correction) shown in FIG. 4A to double-sided paper passing (first side) shown in FIG. 4C, it is necessary to switch the positions of both guide member 205 and branching member 15. Specifically, the guide member 205 switches the position from the first position where the curl correction is performed to the second position where the curl correction is not performed. The guide member 205 also switches the position from the first position for discharging the sheet to the second position for feeding the sheet to the reverse / double-side path side.

  At this time, since both the guide member 205 and the branching member 15 are driven, a driving sound accompanying the switching operation may be generated. Therefore, an unpleasant impression may be given to the user depending on the timing of the two driving sounds. For example, there are cases where two operation sounds are made continuously at short intervals. In order to prevent giving such an unpleasant impression, in the present invention, the drive timings of the guide member 205 and the branch member 15 are made substantially the same. Here, “substantially the same” means a case where the difference between the two operation timings is a short one that cannot be felt by human senses, for example, within 100 milliseconds. In general, the exact same timing is achieved due to variations in drive source switching operation time, software processing, electrical processing, electronic processing variation, and deviations in the target operation timing from the layout position of each device. It is difficult to do. However, according to the results of the sensory evaluation conducted by the inventors of the present application, it is difficult for a user such as a copier or printer to hear a sound that is heard within 100 milliseconds as a sound that sounds at almost the same time, and does not give an unpleasant impression. was gotten. From there, it was determined that the same timing as described above was acceptable up to a deviation within 100 milliseconds. Thus, by making the drive timing of the guide member 205 and the branching member 15 substantially the same, it is possible to prevent the generation of a driving sound that gives an unpleasant impression to the user.

  Next, the driving means for the guide member 205 will be described with reference to FIGS. 5A, 5B, 5C, 6, and 7. FIG. As shown in FIGS. 5A to 5C, the guide member 205 is biased in a direction to close the conveyance path by the tension spring 209, and the stopper portion 205 </ b> A of the guide member 205 comes into contact with a part of the pressure side separation conveyance member 202. Arranged and configured to stop at position. The position at this time is the first position where the angle of the sheet discharged by the pair of conveyance auxiliary roller members is changed.

  On the other hand, on the apparatus main body side, driving means (solenoid 220 and link member 221) for moving the guide member to the second position that does not change the sheet angle is provided (see FIGS. 6 and 7). The link member 221 is configured to be rotatable around a fulcrum 221A, and when the solenoid 220 is attracted, the link member tip is lifted to contact the guide member 205. By making the suction force of the solenoid 220 larger than the biasing force of the tension spring 209 of the guide member 205, the guide member 205 can be rotated counterclockwise in the drawing and moved to the second position. The position where the solenoid 220 is attracted and stopped is the second position, where it stops. In the illustrated embodiment, the first position where the positional relationship between the guide member 205 and the conveyance auxiliary roller member is severe is configured so that the position is completed within the unit of the fixing device 20, and the second position is the main body of the apparatus. Although it is configured to be determined by the driving means on one side, it may be reversed. Further, by adopting a stepping motor or the like as the driving means for the guide member 205, the position of the guide member 205 may be determined in multiple stages.

Next, the drive means of the branch member 15 is demonstrated using FIG.
The branch member 15 is supported around the rotation center α, and there is a branch link member 301 on the central axis of the rotation center. Further, a branch link member 301 and a solenoid link member 302 installed so as to mesh with each other are provided. The solenoid link member 302 is supported so as to be rotatable around the rotation stop β. The solenoid link member 302 is also linked to the branch solenoid 303, and is biased in the arrow direction γ by the link tension spring 304 at the other end. FIG. 8A shows a state in which the branch solenoid 303 is off. In this case, the branch member 15 is urged in the direction of the arrow γ ′ by the force of the link tension spring 304. In this case, the sheet is conveyed in a direction to be discharged out of the apparatus. This is the first state. In contrast, FIG. 8B shows that the branch solenoid 303 is turned on. In this state, the attraction force of the branch solenoid 303 overcomes the urging force of the link tension spring 304, so that the solenoid link member 302 rotates in the direction of the arrow δ. As a result, the urging by the solenoid link member 302 is released, and the branch member 15 rotates in the direction of the arrow δ ′. In this case, the sheet is conveyed along the reverse / double-sided path. This is the second state.

  That is, by using the solenoid 220 and the link mechanism as the driving unit for the branching member 15, the branching member 15 can be moved by turning the solenoid 220 on or off, thereby making the driving unit inexpensive and space-saving. A position switching mechanism can be realized. Note that a stepping motor or the like may be employed as a driving unit for the branch member 15 so that the position of the guide member 205 can be determined in multiple stages.

<Embodiment 2>
A second embodiment of the present invention will be described. In the present embodiment, the position of the fixing exit guide plate is made variable and decurled. In short, a feature is that space is saved by arranging the guide plate arranged at the fixing outlet and the branching claw for paper discharge into a comb-like shape and arranging them alternately.

A second embodiment of the present invention will be described with reference to FIGS. 9 to 15A and 15B.
9 shows the conveyance surface and the pressure-side separating / conveying member 202 as seen from the X view of FIG. 3, and FIG. 10 is a view substantially the same as FIG. 7 used in the description of the first embodiment. As shown in FIG. 9, the driving roller 204 that constitutes the pair of conveyance auxiliary roller members is rotatably supported at both ends of the pressure side separation conveyance member 202 via a sliding bearing 208. A driving force is transmitted from a driving input source (not shown) to the driving gear 210 on the shaft of the driving roller 204 via the idler gear 211 so as to be rotatable. The guide member 205 disposed on the downstream side of the driving roller 204 in the sheet conveying direction is coaxially supported by the driving roller 204 by being fixed to the pressure-side separating and conveying member 202 via the sliding bearing 208, and is centered on the axis of the driving roller 204. It can be rotated. The driving roller 204 rotates in contact with the inner diameter portion of the sliding bearing 208, and the guide member 205 rotates in contact with the outer diameter portion of the sliding bearing 208.

  With the above-described configuration, the distance gap between the driving roller 204 and the guide member 205 can be configured to have the least amount of dimensional tolerance build-up. That is, only the radial distance tolerance from the axis center of each component can be achieved, and the guide member 205 can be moved in a state where the distance between the driving roller 204 and the guide member 205 is kept highly accurate and constant.

  The guide member 205 and the branch member 15 on the downstream side thereof can be independently moved in correspondence with the paper passing mode. Therefore, it is necessary to adopt a configuration in which both do not interfere even if they overlap. Therefore, the guide member 205 is configured in a plurality of claw-like rib shapes along the longitudinal direction of the drive roller 204. That is, as shown in FIG. 12, the claw-shaped rib members of the branching member 15 are inserted between the claw-shaped ribs that are the guide members 205, so that they overlap each other and are independently movable.

  As shown in FIGS. 9 and 10, the drive roller 204 has a plurality of rubber rollers 204a arranged on the shaft 204b at intervals. And as shown in FIG. 13, it is comprised so that it may become the positional relationship into which the nail | claw-shaped rib which is the guide member 205 enters into the part which does not have the rubber roller 204a. In other words, the outer diameter of the rubber roller 204a and the claw-shaped rib that is the guide member 205 are arranged to overlap each other when viewed from the left-right direction in FIG. And the end part of the claw-shaped rib which is the guide member 205 has a driven roller 203 and a driving roller 204 which are a pair of conveyance auxiliary roller members, as indicated by the round portions (indicated by reference numerals R1 and R2) shown in FIG. Is placed close to the nip portion N.

  That is, in order to reliably guide and guide the paper P discharged from the driven roller 203 and the driving roller 204 that form a pair of conveyance auxiliary roller members, the claw-shaped rib tip that is the guide member 205 is disposed close to the driving roller 204. It is important to. Further, from the viewpoint of the curl correction effect of bending the paper P coming out of the driven roller 203 and the driving roller 204 and the stabilization of the transportability, the tip of the claw-shaped rib that is the guide member 205 is disposed close to the nip portion N. This is very important.

  FIG. 15A shows a case where the tip of the claw-shaped rib, which is the guide member 205, is arranged so as to overlap the driving roller 204 (A), and a case where it is arranged with a gap from the outer diameter of the rubber roller 204a of the driving roller 204 (B). -(D) is shown for comparison. FIG. 15B is a comparison diagram between the case where the tip of the guide member 205 is disposed so as to overlap the drive roller 204 and the case where the tip of the guide member 205 is disposed apart from the rubber outer diameter of the drive roller 204 by a certain gap. Show.

  When the tip of the claw-shaped rib that is the guide member 205 is arranged away from the outer diameter of the rubber roller 204a of the drive roller 204, in order to make the curl correction effect by the guide member 205 the same, as shown by the broken line in FIG. Will be placed. The sheet P discharged from the pair of conveyance auxiliary roller members (the driven roller 203 and the driving roller 204) is a line connecting the centers of the driven roller 203, which is the conveyance auxiliary roller member, and the driving roller 204 (indicated by reference sign CL in FIG. 16). ) In the vertical direction. Therefore, at this time, the contact angle between the leading edge of the paper P and the guide member 205 becomes small (the angle θ at the time of overlap arrangement> the angle θ ′ arranged at a distance).

  When the contact angle is reduced, the leading edge of the paper P is buckled, the paper P is bent and conveyed, and in the worst case, the risk of jamming increases. On the other hand, when the contact angle between the leading edge of the sheet and the guide member 205 is large (shallow), the curl correction effect of bending the sheet P by the guide member 205 is reduced. From the above viewpoint, it is necessary to bring the end of the claw-shaped rib constituting the guide member 205 close to the nip portion N between the driven roller 203 and the driving roller 204 which are conveyance auxiliary roller members. Therefore, as described above, the driving roller 204 is formed as a dumpling roller using a plurality of rubber rollers 204a, and the tip of the claw-shaped rib forming the guide member 205 is inserted into a portion where the rubber roller 204a is not present.

  As shown in FIGS. 10 and 12, the guide member 205 is biased in a direction to close the conveyance path by the tension spring 209, and the stopper portion 205 </ b> A of the guide member 205 comes into contact with a part of the pressure side separation conveyance member 202. It is configured to stop at the position. This position is the first position for changing the angle of the sheet discharged from the roller pair.

  Further, as shown in FIGS. 11 and 13, on the apparatus main body side, driving means (solenoid 220 and link member 221) for moving the guide member 205 to the second position that does not change the sheet angle is provided. . The link member 221 is configured to be rotatable around a fulcrum 221A, and when the solenoid 220 is attracted, the link member tip is lifted to contact the guide member 205. By making the suction force of the solenoid 220 larger than the urging force of the guide member 205 (force by the tension spring 209), the guide member 205 rotates counterclockwise in the drawing and moves to the second position. . That is, the position where the solenoid 220 is sucked and stopped is the stop at the second position. Also in this embodiment, the position of the guide plate 205 may be determined in multiple stages by using a stepping motor or the like as the driving means of the guide member 205.

  14 and 15A are diagrams for explaining a specific configuration of the fixing exit guide plate and the paper discharge branch claw. As described above, the branch member 15 and the guide member 205 are staggered in a comb shape (FIG. 14). As a result, as shown in FIGS. 15A and 15D, the transfer portion can be connected in the paper transport direction. Further, by crossing the routes as shown in (A) and (C) of FIG. 15A, it is possible to save space. That is, by using a solenoid, it is possible to save space and cost compared to using a motor. In the present specification, “comb-like portions are staggered” is not limited to the one in which the comb-like portions are arranged in a regular state such as one-to-one, as in the illustrated embodiment. It also includes those in an irregular arrangement state in which one comb-like portion is arranged so that two or more are continuous.

  Further, the position of the branch member 15 in the paper transport path is changed according to the paper thickness. When passing thick paper, as shown in FIG. 15A (A), if the contact angle is raised, the contact force is strong, leading to the generation of scratches and streaks in the image. The branch member 15 is laid at an angle as shown in FIG.

<Embodiment 3>
A third embodiment of the present invention will be described. In the present embodiment, a plurality of decurler claws are used so that the amount of curl correction is changed depending on the location of the sheet in a direction perpendicular to the transport direction. In short, a feature is that by using a plurality of decurler claws, the amount of curl correction can be changed depending on the location of the sheet in a direction perpendicular to the conveying direction.

Embodiment 3 of the present invention will be described with reference to FIGS.
FIG. 17 is a diagram showing a drive configuration by a solenoid of a decurler claw (hereinafter, referred to as a claw-like rib) 150 provided in the plurality of branch members 15 according to the present embodiment. In the present embodiment, the branch member 15 is divided into a plurality of parts perpendicular to the transport direction. By setting it as this structure, the angle of the nail | claw-shaped rib 150 with which the branch member 15 is provided can be changed with a position. Thereby, when only the edge of the paper is curled, the claw-like ribs 150 at both ends can be tilted as shown in FIG. By doing so, an extra contact force is not applied to the central portion of the paper that does not require decurling, so that the image quality is maintained. In the illustrated example, one claw-shaped rib 150 located at the outer ends of the branching members 15 at the left and right ends of the three claw-shaped ribs 15 is tilted. The method of defeating is not limited to this.

  FIG. 18 is a view showing a structure for fixing the angle of the branching member 15. In this structure, a protrusion 151 is provided inside the branch member 15, and the angle of the branch member 15 is determined and fixed by fitting into a hole 153 provided in the shaft 152. In this structure, the angle of the branch member 15 can be manually switched, and a drive source such as a motor is not required. Therefore, it has a configuration that can be realized at low cost and in a space-saving manner.

19 and 20 are diagrams for explaining a configuration example of a structure in which a plurality of branch members 15 are driven by a rotary solenoid 401 and an electromagnetic clutch 402 (see FIG. 19).
Each of the plurality of branch members 15 has a drive means for the rotary solenoid 401. The rotary solenoid 401 can rotate the shaft 15 a of the branch member 15 to change the angle of the branch member 15. Therefore, when the curled state is different between the first side and the second side of the paper when the double-sided sheet is passed, it is possible to switch the angle of the branching member 15 and cope with it more optimally. .

<Embodiment 4>
A fourth embodiment of the present invention will be described. In the present embodiment, as in the third embodiment, the plurality of branch members 15 are driven by a rotary solenoid and an electromagnetic clutch.
This embodiment will be described with reference to FIGS.

21 and 22 are also structural examples in which the branch member 15 is driven by a solenoid.
In the figure, 503 is an electromagnetic clutch, and 502 is a rotary solenoid. The shaft 15a of the branch member 15 is rotated by the rotary solenoid 502, and the branch member 15 is operated by the electromagnetic clutch 503 connected to the shaft 15a. The rotation is in the vertical direction, and the claw-shaped rib 150 swings up and down. The rotary solenoid 502 is preferably one that can change the angle to three or one that can change the rotation angle more finely so that the angle of the branching member 15 can be changed variously. In the figure, reference numeral 504 denotes a spring.

<Embodiment 5>
A fifth embodiment of the present invention will be described. In this embodiment, the decurler branching claw, the fixing exit driving roller, and a part of the fixing unit are provided on the double-sided unit, thereby improving the visibility of the paper when a jam occurs in the reverse path or in the fixing device. It is. By providing the decurler branching claw, the fixing exit driving roller, and a part of the fixing unit in the double-sided unit in the side cover that can open and close the side of the main body, the paper conveyance path on the side of the main body where the paper jam has occurred can be exposed. In addition, since the paper visibility is improved, it is possible to improve the paper visibility and jam handling performance when a jam occurs.

  FIG. 5C is a diagram showing the positional relationship between the link of the external driving means and the guide member 204, and FIG. 14 is a diagram showing the positional relationship between the guide member 205, which is a claw-shaped member, and the branch member 15. Reference is made to the description of the embodiment. 23 to 26 are diagrams for explaining the duplex unit 17 having the guide member 205, the driving roller 204, and the pressure side separating and conveying member 202 according to the present embodiment. In the prior art, as shown in FIG. 23, by opening and closing the side cover 37, the double-sided unit 17 integrated with the side cover 37 can be separated from the main body of the apparatus. You can check and remove the remaining sheets. However, in such a conventional technique, there is a possibility that the sheet remaining in the path near the fixing device 20 cannot be confirmed only by opening and closing the side cover 37.

  Therefore, in this embodiment, as shown in FIGS. 24 and 25, the side cover 37 is opened and closed by providing the double-sided unit 17 with a guide member 205, a driving roller 204 for a conveyance auxiliary roller member, and a pressure-side separation conveyance member 202. Thus, the conveyance path in the vicinity of the fixing can be exposed, and the sheet visibility and the jam handling performance can be improved. Also, as shown in FIG. 26, when the side cover 37 is closed, the guide member 205 is configured to fit with drive means (solenoid 220 and link member 221) for moving the guide member 205 provided in the apparatus main body. ing.

<Embodiment 6>
A sixth embodiment of the present invention will be described. The object of the present embodiment is to decur only the curled portion. It has means for detecting the transport distance of the paper after fixing, and calculates which part of the paper passes through the decurler component in the longitudinal direction. The decurler component performs decurling on the paper based on the calculated information. Since it is known from the evaluation data which part is curled according to the sheet passing condition, decurling can be performed only on the curled part.

  In the present exemplary embodiment, the image forming apparatus includes a detecting unit that detects a conveyance distance from the fixing device 20 of the paper P on which the image is fixed in the fixing device 20. For example, various known sensors constituting such a detecting means can be adopted, and illustration and detailed description thereof are omitted. A driven roller 203 and a driving roller 204, which form a pair of conveyance auxiliary roller members, are arranged downstream of the fixing device 20 in the sheet conveyance direction and upstream of the branching member 15 serving as a sheet conveyance path branching unit. A guide member 205 for guiding the paper P discharged from the pair of auxiliary roller members is provided. Driving means capable of moving to a first position where the guide member 205 comes into contact with the paper P and changes the angle of the paper discharged from the pair of conveyance auxiliary roller members and to a second position where the angle of the paper P does not change. Have. That is, the guide member 205 is rotatably supported at a coaxial position with the driving-side roller shaft of the pair of conveyance auxiliary roller members, and is configured to be movable to the first position and the second position by being rotated. However, a known decurling unit may be arranged at the first position for changing the angle of the paper P, and the decurling unit may not be arranged at the second position where the angle of the paper P is not changed.

  Then, based on the transport distance of the paper P obtained from the detection means, the guide member 205 is driven to the first position at an arbitrary paper transport direction position, and the guide member 205 is moved to the second position at an arbitrary paper transport direction position. Drive to the position. For example, as shown in FIG. 27A, in the case of a sheet P1 curled only in the leading end side in the transport direction, the guide member 205 is driven to the first position only in the leading end side in the sheet transport direction position. From there, driving to return to the second position may be performed to decurl the leading edge of the paper P. It is preferable that the driving to the first position and the operation to return to the second position (decaling operation) are performed on a single sheet P a plurality of times.

  Further, as shown in FIG. 27B, in the case of the paper P2 in which both the leading edge and the trailing edge are curled, first, the decurling operation is performed on the leading edge side at the position in the sheet conveying direction, and then the decurling operation is performed on the trailing edge side. Make it. Of course, it is preferable to perform the decurling operation a plurality of times at both positions.

  Note that the timing of the decurling operation can be changed according to the paper thickness and size of the paper P and the fixing temperature of the fixing device 20. Further, as the driving means for the guide member 205, a mechanism that moves the guide member 205 by operating the link mechanism by turning the solenoid on or off can be adopted. As described above, the driven roller 203 and the driving roller 204 that form a pair of conveyance auxiliary roller members are composed of a driving roller made of a rubber roller and a driven roller having high peelability on the surface. It is possible to use a drive roller (when paper is used).

  The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1: Apparatus main body 2: Bottle accommodating part 3: Transfer apparatus 4C, 4K, 4M, 4Y: Image forming part 5: Photoconductor 6: Charging apparatus 7: Developing apparatus 8: Cleaning apparatus 9: Exposure apparatus 10: Paper feed tray 11 : Paper feed roller 12: Registration roller 13: Paper discharge roller 14: Paper discharge tray 15: Branch member 15a: Shaft 16: Reversing roller 17: Duplex unit 20: Fixing device 21: Fixing belt 22: Pressure roller 23: Heater 24 : Nip forming member 26: Reflecting member 27: Temperature sensor 30: Intermediate transfer belt 31: Primary transfer roller 32: Secondary transfer backup roller 33: Cleaning backup roller 34: Tension roller 35: Belt cleaning device 36: Secondary transfer roller 150 : Decala claws (claw-shaped ribs)
151: Protrusion 152: Shaft 153: Hole 201: Belt side separation / conveyance member 202: Pressure side separation / conveyance member 203: Driven roller 204: Drive roller 204a: Rubber roller 204b: Shaft 205: Guide member 205A: Stopper 207: Holder 208: Slide bearing 209: tension spring 210: drive gear 211: idler gear 220: solenoid 221: link member 301: branch link member 302: solenoid link member 303: branch solenoid 304: link tension spring 401 rotary solenoid 402 electromagnetic clutch 502: rotary solenoid 503 : Electromagnetic clutch 504: Spring F: Arrow N: Nip part P: Paper

JP 2001-48399 A JP-A-9-188456 JP 2012-91891 A JP-A-6-202506 JP 2003-186371 A JP 2012-91891 A

Claims (3)

A fixing device for fixing the image to the recording medium after transferring the image formed by the image forming unit onto the recording medium;
A paper discharge device for discharging the recording medium processed by the fixing device to the outside of the image forming device;
A reversing device for reversing the recording medium processed by the fixing device,
A double-sided device that again conveys the recording medium reversed by the reversing device into the image forming apparatus, a side cover that opens and closes a side surface of the apparatus main body integrated with the double-sided device,
In an image forming apparatus having
A pair of conveyance auxiliary roller members downstream of the fixing device in the recording medium conveyance direction and upstream of the sheet conveyance path branching unit, and the recording discharged from the conveyance auxiliary roller member immediately after the conveyance auxiliary roller member. A guide member for guiding the medium;
The guide member is in contact with the recording medium and is movable to a first position where the angle of the recording medium ejected from the conveyance auxiliary roller member is changed and a second position where the angle of the recording medium is not changed Having means,
The double-sided device has the guide member,
An image forming apparatus comprising and this. The image forming apparatus according to claim 1.
One of the pair of conveyance auxiliary roller members is constituted by a drive roller,
The double-sided device has the drive roller,
An image forming apparatus comprising and this. The image forming apparatus according to claim 1, wherein
The double-sided device has a part of the fixing device.
An image forming apparatus comprising and this.