JPH09267961A - Sheet material reversing and carrying device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the carry-in of a following sheet at the time of reversely rotating a carrying roller so as to perform the image forming processing at a high speed by controlling the sheet material carrying force by a reverse carrying roller with a change-over operation. SOLUTION: When a flapper 14 having a roller 15 as a rotating member at a position opposite to a reverse carrying roller 16 is switched to a carrying passage to a face-up discharging port, the roller 15 is made to abut on the reverse carrying roller 16. When the flapper pipe 14 is switched to a carrying passage to a face-down discharge port 26, the roller 15 is separated from the reverse rotating carrying roller 16. With this structure, since the roller 15 can be separated from the reverse carrying roller 16, even in the cease where the reverse carrying roller 16 is rotated in the opposite direction of the carrying roller 11, carry-in of a following sheet can be performed. Namely, when a following sheet material exists, a tip of a former sheet material, which is switched for back, is detected by a sensor, and thereafter, the flapper 14 is switched to a real line position, and a following sheet can be led in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material reversing / conveying device for reversing a sheet material in the middle of a path for conveying the sheet material. The present invention relates to a carrier device.

[0002]

2. Description of the Related Art Conventionally, in a sheet material reversing / conveying apparatus used in an image forming apparatus such as a copying machine, as shown in FIG. 6, a sheet material S fed along a conveying path is fed into a pair of feeding rollers 51 ,. It is introduced into the switchback section a by 52,
The sheet material S is further fed into the switchback portion a by the forward rotation (the direction of arrow b in the figure) of the pair of conveying rollers 54 and 55 provided in the switchback portion a. When the rear end of the sheet material S is detected by the detection sensors 56 and 57, the conveyance roller pairs 54 and 55 provided in the switchback section a are reversed, and the conveyance roller pairs 54 and 55 are reversed. The sheet material S is fed back by (in the direction of arrow c in the figure) and returned to the transport path again by the pair of unloading rollers 52 and 53. The sheet material S is inverted by this series of operations.

In FIG. 10, reference numerals 51, 52 and 53 are triple rollers. As described above, the rollers 51 and 52 function as a carry-in roller pair, and the rollers 52 and 53 function as carry-out rollers. Further, the detection sensors 56 and 57 are arranged upstream of the carry-in roller pairs 51 and 52 in order to detect the rear end of the sheet material S.
Of the pair of transport rollers 54 and 55, the transport roller 54 is a drive roller that rotates in the forward and reverse directions, and the transport roller 55 is the roller 54.
It is a driven roller that is pressed against and rotates.

[0004]

However, in the above-mentioned conventional example, the sheet material S is reversed by the forward and reverse rotations of the conveying roller pairs 54 and 55 (directions of arrows b and c in the drawing). It was difficult to carry in the next sheet material S while the pair of conveyance rollers 54 and 55 were rotated in the reverse direction (direction of arrow c in the figure). That is, there is a problem that it takes time to invert the sheet material.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to carry in the next sheet material when the conveying roller for reversely conveying the sheet material is reversely rotated, and the image is transferred. An object of the present invention is to provide a sheet material reversing / conveying device suitable for an image forming apparatus that performs a forming process at high speed.

[0006]

A typical constitution of the present invention for achieving the above object is to provide a reverse feed roller which rotates in a direction opposite to the feed direction in order to reverse feed a sheet material being fed. Switching means for guiding the fed sheet material and the fed sheet material upstream of the reverse feeding roller, and the reverse feeding according to the switching operation by the switching means. It is characterized in that it is configured to adjust the sheet material conveying force by the rollers.

Specifically, for example, the switching means has a rotating member at a position facing the reverse feeding roller, and the rotating member serves as the reverse feeding roller when the switching means switches to the reverse feeding path. It is characterized in that it abuts and separates from the reverse feed roller when switched to the feed side transport path.

According to this structure, the carrying force of the reverse feeding roller can be reduced or eliminated. Specifically, since the rotating member can be separated from the reverse feeding roller, the reverse feeding roller rotates. However, it is possible to carry in the next sheet material. Therefore, it is possible to provide a sheet material reversing / conveying device suitable for an image forming apparatus that performs image forming processing at high speed. Further, since the reverse feeding roller always rotates in one direction, there is no need for a complicated drive mechanism and drive control for rotating the roller in the forward and reverse directions, and a low-cost sheet material reversing / conveying device is provided. be able to.

There is also a face-up discharge port for discharging the sheet material with the image side facing up to the outside of the apparatus, and at least one face-down discharge port for discharging the sheet material with the image surface facing down to the outside of the apparatus. However, by disposing a temporary discharge port for temporarily discharging the sheet material outside the apparatus when the sheet material is turned over, the temporary discharge port is provided between the face-up discharge port and the face-down discharge port. Since the sheet material exposed to the outside of the apparatus is protected by the trays attached to the respective discharge ports, the user cannot easily touch it, so that the sheet material is not obliquely fed or damaged. Therefore, the reverse conveyance of the sheet material can be smoothly performed. Moreover, the temporary ejection of the sheet material can be hidden by the trays of the respective discharge ports, so that the aesthetic appearance during operation is also preferable.

When the peripheral speed of the conveying roller on the upstream side of the reverse feeding roller is V1 and the peripheral speed of the reverse feeding roller is V2, the relationship between the peripheral speeds of the two rollers is V1 ≧ V2, Further, the driving force is transmitted to the reverse feeding roller via a torque limiter, and when a torque equal to or more than a set value is applied to reversely feed the sheet material, the reverse feeding roller stops or the conveyance roller By rotating the sheet material in the same direction, even if the sheet material is over-stressed in the process of being inverted and conveyed, and the sheet material is likely to be buckled, the sheet material is conveyed backward. Since the force is reduced or eliminated, the sheet material is not damaged, and more stable reversal conveyance of the sheet material becomes possible.

Further, there is provided a guide member for guiding the sheet material carried out from the image forming apparatus to the nip on the carrying-in side of the carrying roller rotating in the feeding direction, and the guide member is provided at the sheet material carrying-out position of the image forming apparatus. Accordingly, by making it swingable around the rotation center axis of the transport roller, it becomes possible to deal with various image forming apparatuses having different sheet material unloading positions.

Further, the reverse feeding roller is pressed against the conveying roller rotating in the feeding direction to form a nip on the unloading side, and the rotating member provided in the switching means is accompanied by the conveying path switching operation of the switching means. By making contact and separation with respect to the reverse feed roller that is in pressure contact with, it is not necessary to provide the reverse feed roller separately from the transport roller group, and the number of constituent parts is reduced, further lowering the cost. Can be realized.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a sheet material reversing / conveying device to which the present invention is applied will be specifically described with reference to the drawings. In the following embodiments, a sheet material reversing / conveying device used in an image forming apparatus such as a copying machine is described as an example.

[First Embodiment] A sheet material reversing and conveying device according to a first embodiment will be described with reference to FIGS. 1 to 3. First, a schematic configuration of the image forming apparatus will be briefly described with reference to FIG. As shown in FIG. 3, an automatic document feeder 2 that automatically circulates a document is provided on the upper surface of the image forming apparatus 1.
And a sheet material reversing / conveying device 10 having a face-up tray 22 and a plurality of face-down discharge trays 26 is installed downstream (on the left side in the drawing).

The image forming apparatus 1 employs a well-known electrophotographic system, and a detailed description thereof is omitted here. However, an image of a document positioned on the platen glass 3 is transferred to a photosensitive drum by an optical system (not shown). 4 and the drum 4
The toner image is formed by a developing unit 5 provided around the sheet, and is transferred to a sheet material by a transfer unit 6.
Is permanently settled.

The sheet material on which the image forming process has been completed as described above is normally discharged and stacked on a face-up tray by the discharge roller pair 8 with the image face up. However, when images are formed in page order (for example, 10 pages starting from 1 page), if the sheets are sequentially stacked with the image side facing up, the sheet materials will be in the reverse order of the page order. Will be loaded with. In order to arrange them in page order, a sheet material reversing / conveying device 10 to which the present invention is applied as shown in the drawing is mounted near the discharge port 9 of the image forming apparatus 1. As a result, the sheet material is sequentially discharged and stacked on the face-up tray 22 with the image side facing up when image formation is performed in the reverse order of the page order, and when image formation is performed in the page order. The sheet materials are sequentially discharged and stacked on one of the face-down trays 26 in a state where the front and back sides of the sheet materials are turned upside down and the image surface is faced down.

The sheet material reversing / conveying device 10 is configured to adjust the sheet material conveying force by the reverse feeding roller in accordance with the switching operation by the switching means described later. Specifically, when the switching means having a rotating member at a position facing the reverse feeding roller is switched to the conveying path to the face-up discharge port, the rotating member contacts the reverse feeding roller, and the face-down discharge port. The rotation member is configured to separate from the reverse feed roller when the conveyance path is switched to the conveyance path. Hereinafter, a sheet material reversing / conveying device to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a sectional configuration diagram of a sheet material reversing / conveying device to which the present invention is applied, and FIG. 2 is a partially enlarged view of the sheet material reversing / conveying device.

In FIG. 1, reference numerals 11, 12 and 13 denote a group of conveying rollers, which have the same circumference of the conveying roller 11 which is driven and rotated in one direction (the direction of the arrow in the figure) to carry in the sheet material S and carry it out after reversing. A plurality of rotatable rollers 12 and 13 are in pressure contact with each other. That is, the transport roller 11 and the roller 12 which is in pressure contact with the upper side of the roller 11 function as a carry-in roller pair for carrying in the sheet material S, and the transport roller 11 and the roller 13 which is in pressure contact with the lower part of the roller 11 Functions as an unloading roller pair for unloading the sheet material S.

Numeral 14 is a flapper as a switching means, which is arranged on the downstream side of the carry-in roller pairs 11 and 12, and is centered on the rotation center shaft 14a by an actuator means such as a solenoid (not shown). The configuration is such that it can be selectively switched between the solid line position and the two-dot chain line position shown.
That is, the flapper 14 selectively switches a plurality of transport paths downstream of the transport roller 11. Specifically, when the flapper 14 is switched to the position shown by the solid line in FIG. 1, the sheet material S is guided to the switchback portion a in order to be inverted. Further, when the flapper 14 is switched to the position indicated by the chain double-dashed line shown in FIG. 1, the sheet material S is guided to the face-up discharge port 20 with the image side facing up without being inverted. Therefore, by selectively switching the flapper 14, it is possible to select whether the sheet material S is to be discharged and stacked with the image side facing up or to be discharged and stacked with the image surface facing down (image forming order). can do.

A pair of discharge rollers 21 and 22 are arranged at the face-up discharge port 20 to discharge the fed sheet material S onto a face-up tray 23 outside the apparatus. The face-up tray 23 is detachably attached to the apparatus 10, and the discharge roller pair 21,
The sheet materials S discharged by 22 are sequentially stacked and held.

Reference numeral 16 denotes a reverse feed roller, which is constantly rotating in the opposite direction (direction of the arrow in the figure) to the carrying roller 11 in order to carry out the sheet material S carried into the switchback portion a. The reverse feeding roller 16 is below the extension line of the nip tangent line of the carry-in roller pair 11 and 12, and is also in the carry-in roller pair 11 and 12.
It is arranged closer to the pair of carry-in rollers 11 and 12 than the position where the leading edge of the sheet material S carried in from 12 reaches. for that reason,
The sheet material S guided by the flapper 14 switched to the solid line position shown in FIG. 1 is carried into the switchback section a without contacting the reverse feed roller 16.

A roller 15 as a rotating member is rotatably attached to the flapper 14 at a position facing the reverse feed roller 16. Therefore, this roller 15 is a flapper
When 14 is switched to the two-dot chain line position shown in FIG. 1, it comes into contact with the reverse feed roller 14 and is driven to rotate, and when the flapper 15 is switched to the solid line position shown in FIG. Are separated.

That is, the sheet material S carried into the switchback section a by the flapper 14 switched to the solid line position shown in FIG. Is discharged onto the reverse tray 25 of. At this time, the sheet material S is temporarily exposed to the outside of the apparatus, but the temporary discharge port 24 is arranged between the face-up discharge port 20 and a face-down discharge port 26 described later. Therefore, the sheet material S that is temporarily exposed from the temporary discharge port 24 to the outside of the apparatus is protected by the trays 23 and 27 attached near the discharge ports 20 and 26, and the user cannot easily touch it. Therefore, the sheet material S is not obliquely fed or damaged, and the reverse conveyance can be smoothly performed. Furthermore, since the temporary exposure of the sheet material S can be hidden by the trays 23 and 27 of the discharge ports 20 and 26, the aesthetic appearance during operation is also preferable.

On the upstream side of the carry-in roller pairs 11 and 12, sensors 17 and 18 are disposed as detecting means for detecting the rear end of the sheet material S. When the sensors 17 and 18 detect that the rear end of the sheet material S has passed at the time of face-down discharge, the flapper 14 is moved by a solid line shown in FIG. The position is switched from the position to the two-dot chain line position. Therefore, the tip of the flapper 14 is smoothly delivered from the nip of the carry-in roller pair 11, 12 to the nip of the carry-out roller pair 11, 13.

Then, the sheet material S is pushed toward the reverse feed roller 16 by the switching (lowering) operation of the flapper 14. That is, when the flapper 14 is switched to the position indicated by the two-dot chain line shown in FIG.
Is pressed against the reverse feed roller 16, the sheet material S is sandwiched between the reverse feed roller 16 and the roller 15, and is carried out toward the carry-out roller pair 11, 13 in the direction opposite to the carry-in direction.

The sheet material S carried out by the pair of carry-out rollers 11, 13 is guided to one of a plurality of face-down discharge ports 26 on the downstream side thereof, and the image is transferred from the discharge port 26 onto the face-down tray 27. It is discharged and loaded face down. For example, as shown in FIG. 1, the flapper 28 is switched from the solid line position shown in FIG. 1 to the broken line position by a discharge command to the uppermost face-down tray 27, and is provided near the uppermost discharge port 26. The discharge rollers 29 and 30 discharge the sheets onto the face-down tray 27 and stack them. That is, the sheet material S is discharged and stacked with the image surface facing down (image formation order).

1, 31 and 32 are a pair of intermediate rollers, and when the sheet material S is discharged to a face down tray below the uppermost face down tray 27 shown in FIG. It is a roller pair that conveys the material S.

Further, in FIG. 1, reference numeral 19 is a guide member for guiding the sheet material S discharged from the discharge port 9 of the image forming apparatus 1 to the nip between the carry-in roller pairs 11 and 12. The guide member 19 is configured to be swingable around the rotation center axis of the transport roller 11 in accordance with the sheet material discharge position of the image forming apparatus (discharge port, nip of discharge roller pair, etc.). That is, as shown in FIG. 2, the sheet material is reversed to an image forming apparatus in which the delivery position of the sheet material S is different from R, for example, an image forming apparatus in which the delivery position is L or an image formation apparatus in which the delivery position is H. When the transport device 10 is mounted, the posture (upstream end) of the guide member 19 according to the transfer positions R, L, and H, as shown by the chain double-dashed line in FIG. It can be easily changed while maintaining the guide position to. As a result, it is possible to deal with various image forming apparatuses having different discharge positions of the sheet material S.

As described above, the flapper which is the switching means.
By configuring the sheet material conveying force by the reverse feeding roller 16 in accordance with the conveying path switching operation by 14, the conveying force of the reverse feeding roller 15 is reduced (contact with weak force) or eliminated (complete separation). Therefore, the next sheet material can be carried in even if the reverse feeding roller 15 is rotating.

Specifically, as described above, the reverse feeding roller
A flapper 14 having a roller 15 which is a rotating member at a position facing 16 is brought into contact with the reverse feeding roller 16 when the roller 15 is switched to the conveyance path to the face-up discharge port 20 and is fed to the face-down discharge port 26. When the roller 15 is separated from the reverse feeding roller 16 when switched to the conveyance path, the roller 15 can be separated from the reverse feeding roller 16, so that the reverse feeding roller 16 is Can carry in the next sheet material even if it is rotating in the opposite direction.
That is, when there is a succeeding sheet material, the succeeding sheet material can be introduced by switching the flapper 14 to the solid line position after the sensor 35 detects the front end of the switched-back preceding sheet material. Therefore, it is possible to provide a sheet material reversing / conveying device suitable for an image forming apparatus that performs image forming processing at high speed. Further, the conveying roller 11 and the reverse feeding roller 16
Since it always rotates in one direction, it is possible to provide a low-cost sheet material reversing / conveying device, which does not require a complicated driving mechanism and drive control for rotating a roller in the forward and reverse directions which have been conventionally used.

Further, in the sheet material reversing / conveying device, when the peripheral speed of the conveying roller 11 is V1 and the peripheral speed of the reverse feeding roller 16 is V2, the relationship between the peripheral speeds of the rollers 11 and 16 is V1. The setting is such that ≧ V2. As a result, even if excessive stress is applied to the sheet material S in the process of reversing and conveying the sheet material S, and the sheet material S is likely to be buckled, a force is applied to the flapper 14 from the sheet material S in the upward direction. Since the pressure contact between the reverse feed roller 16 and the roller 15 is released, the sheet material conveying force of the reverse feed roller 16 is reduced or eliminated, and the sheet material S is not damaged. Therefore, it is possible to stably perform the reverse conveyance of the sheet material.

[Second Embodiment] A sheet material reversing and conveying apparatus according to a second embodiment will be described with reference to FIG. FIG. 4 is a partially enlarged view showing the configuration of the main part of the sheet material reversing / conveying device according to the present embodiment. Since the overall configuration of the apparatus is substantially the same as that of the above-described first embodiment, members having the same functions are denoted by the same reference numerals, and detailed description is omitted here.

In this embodiment, when the peripheral speed of the conveying roller 11 is V1 and the peripheral speed of the reverse feeding roller 16 is V2, the peripheral speeds of the rollers 11 and 16 are the same as in the above-described embodiments. A peripheral speed difference is provided so that the relationship is V1 ≧ V2, and as shown in FIG. 4, the driving force is transmitted to the reverse feed roller 16 via the torque limiter 33.

In the sheet material reversing / conveying apparatus according to the present embodiment, when the sheet material detecting sensors 17 and 18 arranged on the upstream side of the carry-in rollers 11 and 12 detect the rear end of the sheet material S, the detection signal is sent. Based on this, the switching operation of the flapper 14 is started while the trailing edge of the sheet material S is still held by the carry-in roller pairs 11 and 12. That is, when the sheet material S is fed back, the sheet material S is nipped between the carry-in roller pair 11 and 12 and the feed roller 16 rotating in the opposite direction to the roller pair 11 and 12 for a short time. become.

In the sheet material S in the above-described state, stress starts to occur due to the opposite conveying forces. Then, resistance to the bending of the sheet material S is transmitted to the reverse feeding roller 16,
The torque limiter 33, which is in the middle of driving the reverse feed roller 14,
The sheet material S runs idle due to its resistance. As a result, the driving force is transmitted to the reverse feeding roller 14, and the reverse feeding roller 14 does not rotate in the reverse direction.

Therefore, when stress is applied to the sheet material S in the above-described state, the torque limiter 33 absorbs the stress and the reverse feed roller 14 stops rotating or rotates in the same direction as the carry-in roller 11 rotates. Therefore, the damage to the sheet material S is almost eliminated, and it becomes possible to carry out the stable reversal conveyance of the sheet material.

[Third Embodiment] A sheet material reversing and conveying device according to a third embodiment will be described with reference to FIG. FIG. 5 is a partially enlarged view showing the configuration of the main part of the sheet material inverting / conveying apparatus according to the present embodiment. Since the overall configuration of the apparatus is substantially the same as that of the above-described first embodiment, members having the same functions are denoted by the same reference numerals, and detailed description is omitted here.

In this embodiment, as shown in FIG. 5, the reverse feed roller is a large-diameter roller 34 which also serves as the carry-out roller 13 (see FIG. 1), and the reverse feed roller 34 is used as the carry roller 11.
The roller 15 provided on the flapper 14 is pressed against the lower part of the conveying roller 11 to form a nip on the carry-out side.
It is configured to contact and separate with respect to. As a result, it is not necessary to provide a reverse feed roller separately from the transport roller group, and the number of constituent parts is reduced, so that further cost reduction can be realized.

[Other Embodiments] In the above-described embodiment,
The reverse feed roller 16 only performs reverse rotation, but it is also possible to switch between forward rotation and reverse rotation. Further, the sheet material reversing / conveying device having a plurality of face-down trays is illustrated, but the present invention is not limited to this, and the present invention is effective even if the device has one face-up tray and one face-down tray. Is. Further, the present invention is effective even if the apparatus has a processing unit such as a stapler that performs processing such as binding on the sheet bundle discharged onto the tray.

Further, in the above-described embodiment, the sheet material reversing and conveying device used in the image forming apparatus in which the image surface is formed on the upper surface of the sheet material is exemplified, but conversely, the image surface is formed on the lower surface of the sheet material. In a sheet material reversing / conveying apparatus used in an image forming apparatus, a tray on which sheet materials are discharged and stacked without being reversed is a face-down tray, and a tray on which sheet materials are reversed and discharged and stacked is a face-up tray. The present invention is also effective for the above.

Further, in the above-described embodiment, the copying apparatus combined with the reader or the like has been illustrated as the form of the image forming apparatus, but the present invention is not limited to this. For example, a facsimile apparatus having a transmitting / receiving function, information of a computer or the like. It may be in the form of an image output terminal of a processing device, and the same effects as those described above can be obtained by applying the present invention to the sheet material reversing / conveying device used in these devices.

Further, in the above-mentioned embodiment, the electrophotographic system is exemplified as the recording form by the image forming means, but the present invention is not limited to this, and for example, an ink jet system, a thermal transfer system, a heat sensitive system, a wire dot system. It is also possible to adopt a recording method such as the above, or a recording method other than that, and by applying the present invention to a sheet material reversing / conveying device used in an image forming apparatus adopting these recording modes, The same effect can be obtained.

[0043]

As described above, according to the present invention,
Since it is possible to reduce or eliminate the sheet material conveying force of the reverse feeding roller, specifically, for example, since the nip between the reverse feeding roller and the rotating member can be released, the next sheet material should be carried in. You can Therefore, it is possible to provide a sheet material reversing device suitable for an image forming apparatus that performs image forming processing at high speed.

Further, a temporary discharge port for temporarily discharging the sheet material to be reversed and conveyed out of the apparatus is provided between the face-up discharge port and the face-down discharge port, so that the sheet material is temporarily exposed to the outside. The user can not easily touch the sheet material by protecting the sheet material with the trays attached to the respective discharge ports, so that the sheet material is not obliquely fed or damaged. Therefore, the reverse conveyance of the sheet material can be smoothly performed. Moreover, the temporary ejection of the sheet material can be hidden by the trays of the respective discharge ports, so that the aesthetic appearance during operation is also preferable.

When the peripheral speed of the transport roller is V1 and the peripheral speed of the reverse feed roller is V2, the relationship between the peripheral speeds of the two rollers is V1 ≧ V2, and the driving force is transmitted to the reverse feed roller. Is performed via a torque limiter, and when a torque equal to or more than a set value is applied to reversely feed the sheet material, the reverse feeding roller is stopped or rotated in the same direction as the conveying roller. Even if excessive stress is applied to the sheet material in the process of reversing and transporting the sheet material, the sheet material will be damaged because the transporting force to reversely transport the sheet material is reduced or eliminated. Is not given, and more stable reversal conveyance of the sheet material becomes possible.

Further, a guide member for guiding the sheet material carried out from the image forming apparatus to the nip on the carrying-in side of the carrying roller is centered on the rotation center axis of the carrying roller according to the sheet material carrying-out position of the image forming apparatus. By allowing the sheet material to swing freely, it becomes possible to deal with various image forming apparatuses having different sheet material carry-out positions.

The reverse feed roller is pressed against the feed roller to form a nip on the unloading side, and the rotary member provided in the switching means is
With the configuration of performing contact and separation with respect to the reverse feed roller that is in pressure contact with the transport roller in accordance with the transport path switching operation of the switching means, there is no need to provide a reverse feed roller separately from the transport roller group. Since the number of constituent parts is reduced, further cost reduction can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a sheet material reversing / conveying device according to a first embodiment.

FIG. 2 is an enlarged cross-sectional view of a main part of the sheet material inverting / conveying device according to the first embodiment.

FIG. 3 is a schematic configuration diagram of an image forming apparatus including the sheet material reversing / conveying device.

FIG. 4 is an enlarged cross-sectional view of a main part of a sheet material reversing / conveying device according to a second embodiment.

FIG. 5 is an enlarged sectional view of a main part of a sheet material reversing / conveying device according to a third embodiment.

FIG. 6 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 S: sheet material R, L, H ... sheet material transfer position 1 ... image forming device 2 ... original document feeder 3 ... platen glass 4 ... photoconductor drum 5 ... developing device 6 ... transfer device 7 ... fixing device 8 ... ejection roller Pair 9 ... Ejection port 10 ... Sheet material reversing / conveying device 11, 12, 13 ... Conveying roller 14 ... Flapper 14a ... Shaft 15 ... Roller 16, 34 ... Reverse feeding roller 17, 18, 35 ... Sensor 19 ... Guide member 20 ... Face Up discharge port 21, 22… Ejection roller pair 23… Face up tray 24… Temporary ejection port 25… Reverse tray 26… Face down ejection port 27… Face down tray 28… Flapper 29, 30… Ejection roller pair 31, 32… Intermediate Roller pair 33 ... Torque limiter

Front Page Continuation (72) Inventor Yasuyoshi Hayakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Yukimachi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Stock In the company

Claims (8)

[Claims] 1. A reverse feeding roller that rotates in a direction opposite to a feeding direction to reversely feed a fed sheet material, and a sheet material and a fed sheet which are fed upstream of the backward feeding roller. Switching means for guiding the fed sheet material, and the sheet material conveying force by the reverse feeding roller is adjusted in accordance with the switching operation by the switching means. Inversion transport device. 2. The switching means has a rotating member at a position facing the reverse feeding roller, and the rotating member comes into contact with the reverse feeding roller when the switching means switches to the reverse feeding path, and the feeding side is provided. 2. The sheet material reversing / conveying device according to claim 1, wherein the reversing / conveying device separates from the reverse feeding roller when the conveyance path is switched to the conveyance path. 3. A face-up discharge port for discharging the sheet material to the outside of the apparatus with the image side facing upward, and at least one face-down discharge port for discharging the sheet material to the outside of the apparatus with the image surface facing downward. The sheet material reversing / conveying device according to claim 2, which has. 4. A temporary outlet for temporarily discharging the sheet material out of the apparatus when the sheet material is inverted is disposed between the face-up outlet and the face-down outlet. The sheet material reversing / conveying device according to claim 3. 5. When the peripheral speed of the conveying roller on the upstream side of the reverse feeding roller is V1 and the peripheral speed of the reverse feeding roller is V2, the relationship between the peripheral speeds of the both rollers is V1 ≧ V2. Further, the driving force is transmitted to the reverse feeding roller via a torque limiter, and when a torque equal to or more than a set value is applied to reversely feed the sheet material, the reverse feeding roller is stopped or the feeding roller is conveyed. The sheet material reversing / conveying device according to claim 1 or 2, which rotates in the same direction as the above. 6. A guide member for guiding a sheet material carried out from the image forming apparatus to a nip on a carrying-in side of a carrying roller rotating in a feeding direction, the guide member being a sheet material carrying-out position of the image forming apparatus. 3. The sheet material reversing / conveying apparatus according to claim 1, wherein the sheet reversing / conveying apparatus is capable of swinging about a rotation center axis of the conveying roller. 7. The reverse feeding roller is pressed against a conveying roller rotating in the feeding direction to form a nip on the unloading side, and a rotating member provided in the switching means is attached to the conveying roller in accordance with the switching operation of the switching means. The sheet material reversing / conveying device according to claim 1 or 2, wherein the reverse feeding roller that is in pressure contact is brought into contact with and separated from the reverse feeding roller. 8. An image forming apparatus having an image forming means for recording and forming an image on at least a sheet material, comprising the sheet material reversing / conveying device according to any one of claims 1 to 7. Image forming apparatus.