JP2016118775A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can reduce an influence of dew condensation without complicating and increasing the size of the apparatus.SOLUTION: An image forming apparatus comprises: a second transfer part 130 (transfer part) that transfers a toner image to a sheet; a fixing part 150 that fixes the toner image transferred by the second transfer part 130 to the sheet by using heat; a second sheet conveyance passage R1 (ejection passage) that guides the sheet to which the toner image is fixed by the fixing part 150 toward an ejection port 10; a third sheet conveyance passage R2 (branch passage) that branches from the second sheet conveyance passage R1; and a reverse conveyance roller pair 21 (rotor pair) that is provided on the third sheet conveyance passage R2 to convey a sheet. A control part 30 rotates the reverse conveyance roller pair 21 when sheets are continuously ejected from the ejection port 10 via the second sheet conveyance passage R1 not via the third sheet conveyance passage R2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  2. Description of the Related Art Conventionally, some electrophotographic image forming apparatuses such as copying machines, facsimile machines, and laser printers form images on a first surface (front surface) and a second surface (back surface) of a sheet. In such an image forming apparatus, when images are formed on both sides of a sheet, a toner image is formed on the photosensitive drum, and the toner image is transferred to the first surface of the sheet supplied from the paper feeding unit in the transfer unit. To do. Thereafter, the transferred toner image is fixed on the sheet by a fixing unit provided on the downstream side of the image forming unit, and then the sheet is conveyed to the reversing unit. The reversing unit conveys the sheet to the image forming unit again with the front and back sides reversed, thereby forming an image on the second surface of the sheet.

  Here, in the image forming apparatus, during the fixing process for fixing the toner image to the sheet, the sheet is heated at a predetermined temperature, and moisture contained in the sheet may be evaporated as water vapor due to this heating. Then, dew condensation may occur on the transport roller due to the influence of water vapor generated from the sheet heated by the fixing unit. When dew condensation occurs, moisture adheres to the sheet when the sheet passes through the conveyance roller, and the influence of the moisture causes image defects, conveyance defects, sheet contamination, and the like.

  Therefore, conventionally, an image forming apparatus that includes a fan that blows air and that can prevent condensation by blowing air has been proposed (see Patent Document 1).

JP2013-257383A

  However, in the image forming apparatus described in Patent Document 1, it is necessary to provide a large fan in the image forming apparatus in order to prevent condensation.

  Therefore, the present invention has been made in view of such a situation, and an object thereof is to provide an image forming apparatus capable of preventing the influence of dew condensation without increasing the complexity and size of the apparatus. Is.

  In the image forming apparatus, a transfer unit that transfers a toner image to a sheet, a fixing unit that fixes the toner image transferred by the transfer unit to a sheet using heat, and a toner image formed by the fixing unit. A discharge path that guides the fixed sheet toward the discharge port, a branch path that branches from the discharge path, a pair of rotating bodies that are provided in the branch path and that convey the sheet, and do not pass through the branch path And a control unit that rotates the pair of rotating bodies when sheets are continuously discharged from the discharge port via the discharge path.

  When the sheets are continuously discharged from the discharge port through the discharge path without passing through the branch path as in the present invention, the apparatus is complicated and enlarged by rotating the pair of rotating bodies. In this way, the influence of condensation can be prevented.

1 is a diagram illustrating a schematic configuration of a laser beam printer which is an example of an image forming apparatus according to a first embodiment. FIG. FIG. 3 is a control block diagram of the laser beam printer. 6 is a flowchart showing drive control of a reverse conveying roller pair provided in the laser beam printer. 9 is a flowchart showing another drive control of the reverse conveying roller pair. FIG. 6 is a control block diagram of a laser beam printer according to a second embodiment. 9 is a flowchart showing drive control of a reverse conveying roller pair according to the second embodiment.

<First Embodiment>
Hereinafter, a first embodiment for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a laser beam printer which is an example of an image forming apparatus according to the present embodiment. As shown in FIG. 1, a laser beam printer (hereinafter referred to as a printer) 100 includes a printer main body 101 that is an image forming apparatus main body, an image forming unit 102 that forms an image on a sheet, and a substantially horizontal above the printer main body 101. And an image reading apparatus 103 installed in the apparatus. A discharge space P for discharging sheets is formed between the image reading apparatus 103 and the printer main body 101. The printer main body 101 includes a sheet feeding unit 110 that feeds the sheet S from the sheet feeding cassette 111, a reversing conveyance unit 20 for conveying the sheet on which the image is formed on the first surface to the image forming unit 102, and the like. It has.

  The image forming unit 102 includes a scanner unit 142 and four process cartridges 140 that form toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (Bk). Each process cartridge has a photosensitive drum 141 and a developing device 143. In addition, the image forming unit 102 includes an intermediate transfer unit 145 disposed above the process cartridge 140.

  The intermediate transfer unit 145 includes an intermediate transfer belt 146 that is wound around the secondary transfer inner roller 131 and the like. Further, the intermediate transfer unit 145 includes four primary transfer rollers 144 that are provided inside the intermediate transfer belt 146 and come into contact with the intermediate transfer belt 146 at positions facing the respective photosensitive drums 141. Here, the intermediate transfer belt 146 is disposed so as to be in contact with each photosensitive drum 141, and is driven by a driving unit (not shown) to rotate in the arrow A direction. Then, a positive transfer bias is applied to the intermediate transfer belt 146 by the primary transfer roller 144, whereby each color toner image having a negative polarity on the photosensitive drum is sequentially transferred to the intermediate transfer belt 146 in a multiple transfer manner. As a result, a full color image is formed on the intermediate transfer belt 146.

  A secondary transfer roller 132 is disposed at a position facing the secondary transfer inner roller 131 of the intermediate transfer unit 145. The nip formed by the secondary transfer inner roller 131 and the secondary transfer roller 132 constitutes a secondary transfer unit 130 that transfers the full color image formed on the intermediate transfer belt 146 to the sheet S. Further, a fixing unit 150 is disposed above the secondary transfer roller 132, and a first paper discharge roller pair 11 is disposed downstream of the fixing unit 150 in the sheet conveyance direction.

  The printer main body 101 also includes a control unit 30 that controls the image forming operation of the printer 100, the sheet feeding operation, and the sheet conveying operation during double-sided image formation. The printer main body 101 also has a first sheet conveyance path R for conveying the sheet fed from the sheet feeding unit 110 to the image forming unit 102. Further, the sheet on which the image is formed by the image forming unit 102 and the toner image is fixed by the fixing unit 150 is guided to the discharge port 10 through the second sheet conveyance path R1 (discharge path). The second sheet conveyance path R1 is branched into a third sheet conveyance path R2 (branch path), and a reverse conveyance roller pair 21 (rotary body pair) that conveys the sheet is provided in the third sheet conveyance path R2. Is provided.

  Next, an image forming operation of the printer 100 configured as described above will be described. When the image forming operation is started, laser light is first emitted from the scanner unit 142 based on image information from a personal computer (not shown). Then, the surface of the photosensitive drum 141 that is uniformly charged to a predetermined polarity and potential is sequentially exposed to the laser beam to form an electrostatic latent image on the photosensitive drum. Thereafter, the electrostatic latent image is developed with toner and visualized. Then, the four color toner images on the photosensitive drum are transferred to the intermediate transfer belt 146 by a transfer bias applied to each primary transfer roller 144, and a full color toner image is formed on the intermediate transfer belt 146. The toner remaining on the photosensitive drum is collected in a toner container (not shown) by a cleaning unit (not shown) provided in the process cartridge 140.

  In parallel with the toner image forming operation, the sheet S accommodated in the sheet feeding cassette 111 is sent out by the sheet feeding unit 110, and then the sheet S is conveyed to the skew correction device 120 by the conveying roller pair 121. The skew correction is corrected by the skew correction device 120. Next, the conveyance roller pair 122 provided in the skew feeding correction device 120 is rotated so that the leading edge of the sheet S whose skew feeding has been corrected and the full-color toner image on the intermediate transfer belt are aligned. It is conveyed to the next transfer unit 130. Then, a full-color toner image is collectively transferred onto the sheet S by the secondary transfer bias applied to the secondary transfer roller 132 at the secondary transfer unit 130 (transfer unit).

  Next, the sheet S to which the full-color toner image is transferred is conveyed to the fixing unit 150, and the toner of each color is melted and mixed by receiving heat and pressure in the fixing unit 150, so that the toner image on the sheet S becomes a full-color image. It is fixed. Thereafter, the sheet S on which the toner image is fixed is discharged to a discharge tray 170 provided at the bottom of the discharge space P by the first discharge roller pair 11 provided in the second sheet conveyance path R1.

  When images are formed on both sides of the sheet, the switching member 12 serving as a guide member guides the sheet to the reverse conveyance unit 20 from the first position indicated by the solid line that directs the sheet toward the first discharge roller pair 11. To the second position indicated by the broken line. The switching member 12 is rotatably provided (movable) at a branch portion between the second sheet conveyance path R1 and the third sheet conveyance path R2. As a result, the sheet on which the image is formed on the first surface reaches the second sheet discharge roller pair 13 provided in the third sheet conveyance path R2 and capable of forward / reverse rotation. By reverse rotation, the paper is conveyed to the reverse conveyance unit 20 in a reversed state. Thereafter, the sheet is re-conveyed to the secondary transfer unit 130 through the reverse conveying unit 20, and an image is formed on the second surface opposite to the first surface.

  Then, after the toner image is fixed again by the fixing unit 150, the sheet S on which images are formed on both sides is discharged onto the paper discharge tray 170 by the first paper discharge roller pair 11. Alternatively, when the number of sheets stacked on the discharge tray 170 increases, the switching member 12 is moved to the first position, and the sheet is discharged onto the discharge tray 170 by the second discharge roller pair 13. .

  Further, the reverse conveyance unit 20 includes a first double-sided conveyance path R3 and a second double-sided conveyance path R4. The first duplex conveyance path R3 guides the sheet switched back by the reverse conveyance roller pair 21 to the first sheet conveyance path R, and the second duplex conveyance path R4 is switched back by the second discharge roller pair 13. The sheet is guided to the first sheet conveyance path R. The reverse conveying roller pair 21 is disposed above the branch point B1 of the second sheet conveying path R1 and the third sheet conveying path R2. For example, when a small-size sheet is re-conveyed, the sheet is conveyed to the second double-side conveyance path R <b> 4 by the reverse conveyance roller pair 21.

  FIG. 2 is a control block diagram of the printer 100 according to the present embodiment. As illustrated in FIG. 2, the control unit 30 includes a CPU 31, a ROM 32 that stores control software and data storage, and a RAM 33 that forms a work area of the CPU 31. Then, the CPU 31 develops software and data read from the ROM 32 on the RAM 33 and activates the software, and controls each part of the printer 100 to perform a desired image forming process. In the present embodiment, the ROM 32 has a single-sided printing mode in which an image is printed on one side, and a double-sided printing mode in which a sheet with an image printed on one side is conveyed to the third sheet conveyance path R2 and printed on both sides of the sheet. ,have.

  Further, the control unit 30 includes an image forming unit 102, a fixing unit 150, a switching member 12, a reverse conveyance roller pair 21, and a counter 35 that counts (counts) the number of sheets discharged from the discharge port 10. , Are connected to each other. Further, an operation unit 36 for setting the number of sheets to be continuously discharged is connected to the control unit 30.

  The control unit 30 controls the image forming unit 102 to perform image forming processing such as development and transfer, and controls the heater temperature of the fixing unit 150 to perform image fixing processing. The control unit 30 controls the switching member 12 to be switched to the first position or the second position by a solenoid (not shown). Further, as will be described later, when a predetermined number of sheets or more are continuously discharged, the control unit 30 controls the reverse conveying roller pair 21 to rotate (idle) for a predetermined time before the continuous discharge ends. .

  By the way, when the sheet S is discharged onto the discharge tray 170 by the first discharge roller pair 11, the reverse conveyance roller pair 21 is always in pressure contact because the sheet S does not pass through the reverse conveyance roller pair 21. Stopped in a state. For this reason, when the water content of the sheet S evaporates in the fixing unit 150, for example, when the printer 100 is not sufficiently warmed, water vapor stays in the nip portion of the reverse conveying roller pair 21 positioned above the fixing unit 150. .

  Then, when the sheets S are continuously discharged and a predetermined number of sheets are discharged, the water vapor is condensed at the nip portion of the reverse conveying roller pair 21. In the case of single-sided image formation in which an image is formed only on the first surface (front surface), the reverse conveyance roller pair 21 increases as the number of sheets discharged from the first discharge roller pair 11 increases or the sheet size increases. The amount of dew condensation at the nip part increases.

  In this state, when the sheet S is guided by the switching member 12 and conveyed to the reverse conveyance roller pair 21, dew condensation attached to the nip portion of the reverse conveyance roller pair 21 adheres to the sheet S. That is, after a predetermined number of sheets or more are continuously discharged from the first discharge roller pair 11, when the sheets are conveyed to the reverse conveyance roller pair 21, dew condensation adheres to the sheet S. In this state, when the sheet S is conveyed to the reverse conveying unit 20 to form an image on both sides and then passes through the secondary transfer unit 130, a toner image is formed on a portion of the sheet S where moisture has adhered. As a result, an abnormal image with dew marks is formed on the sheet.

  Therefore, in the present embodiment, in the case of single-sided image formation, the reverse conveyance roller pair 21 is rotated before the sheet is conveyed by the reverse conveyance roller pair 21. That is, the reverse conveyance roller pair 21 rotates without holding the sheet. As a result, water vapor staying in the vicinity of the reverse conveying roller pair 21 is released, and even if condensation occurs, the condensation can be dried. Note that the rotation of the reverse conveying roller pair 21 needs to be limited as much as possible from the viewpoints of energy saving and quietness that have been further demanded in recent years.

  For this reason, in the present embodiment, in the single-sided printing mode, when a predetermined number or more sheets that may cause condensation are continuously discharged, the reverse conveying roller before the continuous discharge of the sheets is completed. The pair 21 is rotated (idling) for a predetermined time. Furthermore, the anti-condensation effect is improved by molding one or both of the pair of reverse conveying rollers 21 with a foam material having a water absorption property that absorbs water vapor and condensation.

  Next, the drive control of the reverse conveying roller pair 21 according to this embodiment will be described with reference to the flowchart shown in FIG. 3 and 4, “Y” means YES, and “N” means NO. First, the control unit 30 checks whether or not the printing mode for forming an image on a sheet is the single-sided printing mode for forming an image on one side of the sheet (step S100). In the case of the single-sided printing mode (Y in step S100), it is determined whether or not the first paper discharge roller pair 11 discharges (step S101). Here, in the single-sided printing mode and when discharging by the first paper discharge roller pair 11, dew condensation is likely to occur on the reverse conveyance roller pair 21. In the present embodiment, the single-sided printing mode and the mode in which a predetermined number of sheets or more are discharged from the discharge port 10 via the first sheet conveyance path R1 are referred to as idling mode.

  For this reason, the control unit 30 thereafter determines whether or not the operation unit 36 has set continuous discharge of a predetermined number of sheets or more. When continuous discharge of a predetermined number of sheets or more is set and the first discharge roller pair 11 discharges (Y in Step S101), the control unit 30 discharges according to the count information from the counter 35. It is determined whether the number of sheets to be printed is N (predetermined number). When the number of discharged sheets is N (Y in step S102), that is, when the discharged sheets are the Nth (predetermined number of sheets), the control unit 30 moves the reverse conveying roller pair 21. Driven and idled for a predetermined time (step S103). In the present embodiment, idling means that the roller pair rotates without sandwiching the sheet. When the number of sheets discharged to the discharge port 10 is less than a predetermined number (less than N), the control unit 30 does not idle the reverse conveying roller pair 21 (N in step S102).

  Here, the idling of the reverse conveying roller pair 21 is input by another job for conveying the sheet using the reverse conveying roller pair 21 following the job for continuously discharging the sheets by the first discharge roller pair 11. Run even if not. This is because when another job for conveying a sheet using the pair of reverse conveying rollers 21 is input, the other job can be dealt with quickly. That is, the idling control of the reverse conveyance roller pair 21 is executed before the sheet is conveyed to the third sheet conveyance path R2.

  By controlling the reverse conveying roller pair 21 in this way, the number of discharged sheets becomes N during execution of the idling mode, and the condensation can be dried even when the condensation occurs. Further, only when the continuous sheet discharge number in the single-sided printing mode in which condensation is likely to occur is large, the reverse conveyance roller pair 21 is rotated, so that the minimum necessary number of the reverse conveyance roller pair 21 can be driven. Energy saving and quietness can be improved when there are few.

  When the reverse conveying roller pair 21 is idling, the other rollers arranged downstream in the sheet conveying direction from the reverse conveying roller pair 21 do not rotate. In the present embodiment, the other rollers are, for example, a pair of rotating bodies provided along the second paper discharge roller pair 13 and the first double-sided conveyance path R3. Thereby, energy-saving property and silence can be improved more.

  The predetermined number of discharged sheets N varies depending on the sheet size. For this reason, in the present embodiment, the predetermined number of discharged sheets N is 10 for large size sheets, and 20 for small size sheets. Further, when the number of sheets on which an image is formed in the single-sided printing mode is large, N or more sheets are discharged again until the job is finished after the drive control of the reverse conveying roller pair 21 is performed. There is a case. In this case, when the number of discharged sheets reaches N, the reverse conveying roller pair 21 may be idled again.

  As described above, in the present embodiment, when a predetermined number or more of sheets are continuously discharged, the number of discharged sheets is N before the continuous discharge of sheets is completed. Sometimes the reverse conveying roller pair 21 is idled for a predetermined time. As a result, even when condensation occurs on the reverse conveying roller pair 21, the condensation can be dried. As a result, when the sheet is conveyed by the reverse conveying roller pair 21, it is possible to prevent the condensation from adhering to the sheet. It is possible to prevent the influence of condensation on the image quality.

  Further, by rotating the reverse conveyance roller pair 21 idle for a predetermined time to dry the condensation, the condensation can be eliminated without releasing the nip of the reverse conveyance roller pair 21. For this reason, a mechanism for releasing the nip of the reverse conveying roller pair 21 is not required, and the configuration can be simplified. That is, when a predetermined number of sheets or more are continuously discharged as in the present embodiment, the reverse conveying roller pair 21 is idled for a predetermined time before the continuous discharge of the sheets is completed. Condensation can be prevented without increasing complexity and size. Further, it is not necessary to rotate the pair of reverse conveying rollers 21 at all times, so that the energy saving and the influence on the operation sound can be reduced.

  In the present embodiment, when the number of discharged sheets reaches the Nth, the reverse conveying roller pair 21 is idled. However, the present invention is not limited to this. For example, depending on the environment in which the printer 100 is installed, when the image formation in the single-sided printing mode is started, there is a case where condensation has already occurred on the reverse conveying roller pair 21.

  In this case, as in the flowchart shown in FIG. 4, the control unit 30 determines whether or not the printing mode is the single-sided printing mode (step S200). If the printing mode is the single-sided printing mode (Y in step S200) and the sheet is discharged by the first discharge roller pair 11 (Y in step S201), the reverse conveying roller before the first sheet is conveyed. The pair 21 is driven to idle for a predetermined time (step S202). Then, the control unit 30 determines whether or not the number of discharged sheets is N (predetermined number) based on the count information from the counter 35 (step S203). When the number of discharged sheets reaches N (Y in step S203), the control unit 30 drives the reverse conveying roller pair 21 to idle for a predetermined time (step S204).

  If the reverse conveyance roller pair 21 is rotated when the number of discharged sheets is N, and condensation cannot be sufficiently prevented, the sheet is discharged at an early timing, that is, when the discharged sheets are smaller than the Nth sheet. The reverse conveying roller pair 21 may be driven for a predetermined time. In other words, it may be controlled to start the rotation of the reverse conveying roller pair 21 while the sheets are continuously being discharged from the second sheet conveying path R1. That is, as long as the control unit 30 is executing the idling mode, the reverse conveying roller pair 21 may idly rotate at any timing.

  Furthermore, if the dew condensation cannot be sufficiently prevented even if the reverse conveyance roller pair 21 is rotated, the rotation speed of the reverse conveyance roller pair 21 may be set higher than the rotation speed at the time of conveying the sheet.

  For example, when the sheet is discharged by the second discharge roller pair 13 before the continuous discharge of the sheet is completed, the reverse conveyance roller pair 21 is driven for a predetermined time before the continuous discharge of the sheet is completed. You may make it control to carry out.

<Second Embodiment>
In the first embodiment described above, in the single-sided printing mode, the reverse conveyance roller pair 21 is idled in response to the number of sheets discharged from the discharge port 10 being N (predetermined number). Illustrated. In the second embodiment, as shown in FIG. 5, a timer 55 is connected to the control unit 30 instead of a counter.

  The control flow of the control unit 30 in the second embodiment will be described with reference to FIG. 6, but the description of the same reference numerals in FIG. 6 as those in FIG. 3 described in the first embodiment will be omitted. Here, the operation in which sheets are continuously discharged from the single-sided printing mode and the discharge port 10 is referred to as a continuous discharge operation.

  When the continuous discharge operation is being executed (step S101Y), the timer 55 measures the duration of the continuous discharge operation. When the control unit 30 determines that the duration time measured by the timer 55 is equal to or longer than the predetermined time T (Y in step 302), the control unit 30 causes the reverse conveyance roller pair 21 to idle. If the time measured by the timer 55 is less than the predetermined time (less than the predetermined time T), the control unit 30 does not idle the reverse conveying roller pair 21 (N in step S302).

  Here, the idling of the reverse conveying roller pair 21 is input by another job for conveying the sheet using the reverse conveying roller pair 21 following the job for continuously discharging the sheets by the first discharge roller pair 11. Run even if not. This is because when another job for conveying a sheet using the pair of reverse conveying rollers 21 is input, the other job can be dealt with quickly. That is, the idling control of the reverse conveyance roller pair 21 is executed before the sheet is conveyed to the third sheet conveyance path R2.

  As a result, water vapor staying in the vicinity of the pair of reverse conveying rollers 21 is released to reduce the occurrence of condensation, and the generated condensation can be dried. Further, it is possible to drive the minimum necessary number of the reverse conveying roller pair 21 and to improve energy saving and quietness.

  In the first and second embodiments, the reverse conveying roller pair 21 is not limited to a roller, and one or both of them may be constituted by another rotating body such as a belt.

  10: Discharge port / 12: Guide member (switching member) / 21: Rotating body pair (reverse conveyance roller pair) / 30: Control unit / 35: Counter / 55: Timer / 130: Transfer unit (secondary transfer unit) / 150: fixing unit / R1: discharge path (second sheet conveyance path) / R2: branch path (third sheet conveyance path) / S: sheet

Claims (17)

A transfer portion for transferring a toner image to a sheet;
A fixing unit that fixes the toner image transferred by the transfer unit to a sheet using heat;
A discharge path for guiding the sheet on which the toner image has been fixed by the fixing unit toward the discharge port;
A branch path branched from the discharge path;
A pair of rotating bodies provided in the branch path for conveying a sheet;
A controller that rotates the pair of rotating bodies when sheets are continuously discharged from the discharge port via the discharge path without passing through the branch path;
An image forming apparatus comprising: The control unit starts the rotation of the pair of rotating bodies at a predetermined timing after starting the operation of continuously discharging sheets from the discharge port through the discharge path.
The image forming apparatus according to claim 1. The control unit rotates the pair of rotating bodies in response to a predetermined number of sheets being continuously guided to the discharge port through the discharge path.
The image forming apparatus according to claim 2. A counter for measuring the number of sheets continuously discharged from the discharge port;
The control unit rotates the pair of rotating bodies when the number of sheets measured by the counter reaches the predetermined number.
The image forming apparatus according to claim 3. The predetermined number is set according to the size of the sheet,
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. The control unit does not rotate the pair of rotating bodies when the number of sheets continuously discharged from the discharge port through the discharge path is less than a predetermined number,
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. The control unit rotates the pair of rotating bodies according to a continuation time of an operation of continuously discharging sheets from the discharge port through the discharge path reaching a predetermined time.
The image forming apparatus according to claim 2. A timer for measuring the duration of the operation,
When the duration measured by the timer reaches the predetermined time, the control unit rotates the pair of rotating bodies.
The image forming apparatus according to claim 7. The predetermined time is set according to the size of the sheet,
The image forming apparatus according to claim 7, wherein the image forming apparatus is an image forming apparatus. The controller does not rotate the pair of rotating bodies when the duration of the operation of continuously discharging sheets from the discharge port through the discharge path is less than a predetermined time,
The image forming apparatus according to claim 7, wherein the image forming apparatus is an image forming apparatus. The branch path guides the sheet on which the toner image is formed to the transfer portion again.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The rotating body pair is disposed above the fixing unit.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. Provided in the branch path, provided with another rotating body pair disposed downstream in the sheet conveying direction than the rotating body pair,
The control unit does not rotate the other rotating body pair when the sheet is continuously discharged from the discharge port through the discharge path without passing through the branch path.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The control unit, when the sheet is continuously discharged from the discharge port through the discharge path without passing through the branch path, than when the sheet is guided to the branch path, Rotating the rotating body pair quickly,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. At least one of the pair of rotating bodies is formed from a foam material,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. A guide that is provided at a branch portion between the discharge path and the branch path and is movable between a first position for guiding the sheet toward the discharge port and a second position for guiding the sheet toward the branch path. With components,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The controller can stop the rotation of the pair of rotating bodies during the operation of continuously discharging sheets from the discharge port via the discharge path without passing through the branch path.
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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