JP2001253591A - Sheet conveyor of image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveyor of an image forming device capable of making a waste of sheet less by re-utilizing a stayed sheet other than a jammed sheet stayed in the image forming device at the time of jam generation to the maximum and rapidly and easily carrying out a jam processing. SOLUTION: The sheet conveyor of the image forming device of the present invention is provided with a sheet conveying passage 121 extending from paper feed parts 97, 98, 99, 100 via image forming parts 79, 80 through an image fixing part 74; and circulation conveying means 51, 70, 76, 77, 86 for conveying a stayed sheet other than a jammed sheet stayed in the sheet conveying passage 121 to the outside of the sheet conveying passage 121 at the time of jam generation and once accommodating it and again re-feeding a sheet to the sheet conveying passage 121 after completion of the jam processing and feeding it to the image forming parts 79, 80.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet conveying device used for an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction peripheral thereof.

[0002]

2. Description of the Related Art Conventionally, for example, in Japanese Patent Application Laid-Open No. 9-244482, in a sheet post-processing apparatus connected to an image forming apparatus, first and second sheet conveying paths branched, and first and second sheet conveying paths are branched. And first and second discharge trays respectively disposed on the downstream side in the sheet conveyance direction of
When a jam occurs in the first sheet conveyance path, the subsequent sheets are discharged to a second discharge tray via the second sheet conveyance path.

Also, for example, in Japanese Patent Application Laid-Open No. 7-12098, in a sheet conveying device of an image forming apparatus, when a jam occurs, a sheet staying downstream of the jam sheet is discharged to the outside of the image forming apparatus. Sheets that can be discharged to the outside of the image forming apparatus are discharged even if they are retained on the more upstream side, and sheets that cannot be discharged are conveyed to a position just before the jam sheet, and the conveyance is restarted after the jam sheet is removed by the user's hand. An apparatus that discharges the image to the outside of the image forming apparatus is disclosed.

[0004]

However, in the case of the former publication, when a jam occurs in the sheet conveying path or the image forming apparatus upstream of the branch point of the first and second sheet conveying paths, image forming is not performed. The operation of the apparatus and the sheet post-processing apparatus must be stopped, and the user must manually remove not only the jammed sheet but also all other stagnated sheets. In many cases, even those that can be reused are discarded, resulting in waste of sheets.

In the case of the latter publication, the jammed sheet and a plurality of sheets staying upstream of the jammed sheet stay in the same sheet conveyance path, so that the jammed sheet is less damaged. In some cases, the jam sheet cannot be distinguished from other staying sheets,
There is a possibility that the user may manually remove the staying sheet that does not need to be removed, and in this case also, the sheet is wasted. Furthermore, the example of this publication is a case where the image is applied to an electrophotographic image forming apparatus. The sheet is wasted and the sheet is wasted.

Accordingly, the present invention is to minimize the waste of sheets by maximally reusing the staying sheets other than the jamming sheets staying in the image forming apparatus at the time of the occurrence of the jam, and to quickly perform the jam clearance. An object of the present invention is to provide a sheet conveying device of an image forming apparatus that can be easily performed.

[0007]

In order to achieve the above object, a sheet conveying device of an image forming apparatus according to the present invention comprises a sheet conveying path extending from a sheet feeding section through an image forming section to an image fixing section; A circulating sheet other than the jammed sheet that stays in the sheet conveyance path at the time of occurrence is conveyed out of the sheet conveyance path and temporarily stored therein, and after the jam processing is completed, recirculated to the sheet conveyance path and sent to the image forming unit. Transport means.

In the sheet conveying apparatus of the image forming apparatus according to the present invention, the circulating conveying means conveys a stagnated sheet on which an image has not yet been formed by the image forming section, and a first circulating path. A storage unit that temporarily stores the stagnated sheets conveyed along the path, and a supply unit that sends out the stagnated sheets from the storage unit to the sheet conveyance path, and / or the image forming unit A second circulation path for conveying a stagnant sheet on which image formation has been completed or in the middle and the image has not been fixed by the image fixing unit, and an unfixed image provided in the second circulation path. An image removing device for removing from the sheet;
The storage device may include a storage unit that temporarily stores the stagnated sheets conveyed through the second circulation path, and a supply unit that sends the stagnated sheets from the storage unit to the sheet conveyance path.

Further, in the sheet conveying device of the image forming apparatus according to the present invention, the accommodating unit may also serve as a sheet re-feeding unit used in a duplex printing mode.

Further, the sheet conveying apparatus of the image forming apparatus of the present invention may be provided with a cutting means for cutting the sheet of which the image is fixed or in the process of fixing the image when the jam occurs, among the staying sheets.

According to another aspect of the present invention, there is provided a sheet conveying device for a sheet conveying device, which extends from a sheet feeding portion through an image forming portion to an image fixing portion, and a sheet conveying means for conveying a sheet in the sheet conveying route. And, when a jam occurs, stop the staying sheet staying in the sheet conveying path on the spot,
And control means for controlling the sheet conveying means so as to restart the conveyance of the staying sheet after the completion of the jam processing.

According to another aspect of the present invention, when the sheet size is changed before the occurrence of a jam and after the completion of the jam processing, the staying sheet is discharged out of the image forming apparatus. You may.

[0013]

According to the sheet conveying apparatus of the image forming apparatus of the present invention, when a jam occurs, a sheet other than the jammed sheet staying in the sheet conveying path is conveyed to the outside of the sheet conveying path, temporarily stored therein, and after the jam processing is completed, A circulating transport unit is provided for re-feeding the paper to the transport path and sending it to the image forming unit. Therefore, when a jam occurs, the user removes only the jammed sheet and causes the image forming apparatus to resume operation. If the user resumes the operation of the image forming apparatus, most of the remaining sheets other than the jammed sheet are re-supplied to the image forming unit by the circulating conveyance unit. The paper will be reused. As a result, when a jam occurs, the user removes all the jammed sheets and other staying sheets and then restarts the operation of the image forming apparatus.
Sheet waste can be reduced, and jam clearance can be performed quickly and easily.

According to another aspect of the present invention, there is provided a sheet conveying apparatus for an image forming apparatus in which a staying sheet other than a jammed sheet staying in a sheet conveying path when a jam occurs is stopped immediately, and the jammed sheet is conveyed after the jam processing is completed. Since the sheet conveying means is controlled by the control means so as to restart, the time required for feeding the image to the image forming unit when the operation of the image forming apparatus is restarted after the jam processing is completed can be shortened. Can be resumed quickly.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a copier 130 including a sheet conveying device according to an embodiment of the present invention.

A platen 131 is provided above the copying machine 130.
An exposure lamp 55 that irradiates light to the original placed thereon and a mirror 54 that captures the reflected light are provided. These elements 54 and 55 constitute a first slider.
When the first slider moves along the platen 131 in the direction of arrow a to scan the document surface, the mirrors 52 and 53 constituting the second slider move in the same direction at half the speed of the first slider. The light reflected by the mirror 52 of the second slider enters the surface of the photosensitive drum 80 via the lens 57 and the mirrors 63, 65, 62.

Around the photosensitive drum 80, a drum 80
In the rotation direction, a charging charger 61 for uniformly charging the surface of the drum 80 and an electrostatic latent image formed on the surface of the drum 80 by the incidence of the reflected light are developed with toner to form a toner image. Developing device 67 and drum 80
A transfer charger 79 for transferring the upper toner image onto a sheet such as paper, a cleaner 59 for removing toner remaining on the drum 80 after the transfer, and an eraser for removing residual charges on the surface of the drum 80 A lamp 60 is provided. In the present embodiment, an opposing portion between the photosensitive drum 80 and the transfer charger 79 corresponds to an image forming unit where a toner image is formed on a sheet.

A paper feed unit is provided below the copying machine 130. The paper feed unit is composed of paper feed cassettes 97, 98, 99, and 100 arranged in four stages in the vertical direction. Sheets are stacked and housed in the paper feed cassettes 97, 98, 99, 100, respectively. The sheets are stored in the sheet cassettes 97 and 9.
8, 99, 100 from any one of the paper feed rollers 22,
The rollers 25, 29, and 33 are sent to the side (right side in FIG. 1) by the rotation of the separation rollers 21, 27, 31, and 35.
The sheets are sent out one by one by being judged.

A sheet conveying path 121 extends from the sheet feeding section. The sheet conveying path 121 is provided for the photosensitive drum 8.
The fixing roller 74 extends to the discharge roller 94 through an image forming unit which is a portion where the transfer charger 79 and the transfer charger 79 face each other. The sheet conveying path 121 is provided with vertical conveying rollers 18, 15, 12, 9, an intermediate roller 3, a timing roller 1, and a conveying belt 84, each constituting a sheet conveying unit. By these sheet conveying means, the sheet sent from any one of the sheet cassettes 97, 98, 99, 100 is conveyed through the sheet conveying path 121 as follows.

When it is confirmed by the paper feed sensors 24, 28, 32, and 36 that the sheet has been fed from any one of the paper feed cassettes 97, 98, 99, and 100, a vertical transport roller as a sheet transport means is provided. The sheets are conveyed upward along the sheet conveying path 121 by 18, 15, 12, and 9. At this time, the passage of the sheet is detected by the vertical conveyance sensors 19, 1
6, 13 and 10. Further, when the passage of the sheet is confirmed by the pre-image forming sensor 2, the sheet is fed by the intermediate roller 3 to just before the timing roller 1. Then, the sheet is temporarily stopped while being sandwiched by the nip portion of the timing roller 1, and then sent to the image forming section in synchronization with the toner image formed on the photosensitive drum 80. Thereby, the photosensitive drum 80
The upper toner image is transferred to the sheet. The sheet on which the toner image has been transferred is sent to the fixing device 74 by the transport belt 84. At this time, the passage of the sheet is confirmed by the pre-fixing conveyance sensor 96. The toner image is heated and fixed on the sheet by passing through the fixing device 74. Note that reference numeral 9
Reference numeral 0 indicates a fixing cam, and reference numeral 91 indicates a fixing device exit roller.

Here, in the single-sided printing mode, the sheet that has passed through the fixing device 74 is discharged to the outside of the copying machine 130 by the rotation of the discharge roller 94. At this time, the passage of the sheet is confirmed by the sheet discharge sensor 95.

On the other hand, in the double-sided printing mode, the position of the switching claw 93 provided immediately before the discharge roller 94 is switched, so that the sheet passing through the fixing device 74 branches off from the sheet conveying path 121 and extends downward. Refeeding conveyance path 12
3 is introduced. At this time, the passage of the sheet is confirmed by the branch sensor 92. Then, the sheet is sent to the lowermost switchback conveyance path 124 by rotation of the switchback roller 89. At this time, the switchback sensor 88 confirms that the sheet has been sent to the switchback conveyance path 124.

Thereafter, the switched back sheet is
The sheet is accommodated in the sheet re-feeding device 86 as accommodation means by the rotation of the rollers 87, 72, 71. At this time, the accommodation sensor 73 confirms that the sheet has been sent to the sheet re-feeding device 86. Then, the sheet is sent out of the sheet re-feeding device 86 by the rotation of the sheet re-feeding roller 70 as a feeding means, and forms the image on the remaining surface.
8 ensures that the sheet is transported one sheet at a time.
The sheet is re-supplied to 1. At this time, the passage of the sheet is confirmed by the re-feed sensor 69. While the sheet re-fed in this manner is conveyed again through the sheet conveying path 121, the toner image is transferred to the remaining surface in the image forming unit, and the toner image is heated and fixed by the fixing unit 74. Thereafter, the sheet is discharged from the discharge roller 94 to the outside of the copying machine 130.

A manual feed tray 1 is provided on the side of the copying machine 130.
10 is attached. The sheet set on the manual feed tray 110 is sent to the sheet conveying path 121 by the rotation of the manual feed rollers 7 and 5. At this time, the passage of the sheet is confirmed by the manual feed sensor 8. Thereafter, the sheet is subjected to one-sided printing or two-sided printing in the same process as described above, and then discharged to the outside of the copying machine 130 by the discharge roller 94.

In the sheet conveying path 121, a switching claw 6 is provided immediately before the intermediate roller 3. At the position of the switching claw 6, the first circulation conveyance path 77 branches from the sheet conveyance path 121. The first circulating conveyance path 77 extends to the sheet re-feeding device 86. By rotating the switching claw 6 to change its position, the sheet conveyed from the upstream side of the sheet conveying path 121 is sent to the first circulation conveying path 77, and the sheet is thereafter rotated by the conveying rollers 83 and 85 which rotate. The sheet is conveyed through one circulation conveyance path 77 and temporarily stored in the sheet re-feeding device 86. At this time, it is confirmed by the storage sensor 50 that the sheet has been stored in the re-feeding device 86. Refeeder 8
The sheet once stored in the sheet feeder 6
The sheet is re-supplied to the sheet conveying path 121 by the separation roller 68 and the separation roller 68 and sent to the image forming unit. The switching claw 6, the first circulating conveyance path 77, the re-feeding device 86, the re-feeding roller 70, and the like constitute a part of the circulating conveyance means.

In the sheet conveying path 121, the fixing device 7
Just before 4, another switching claw 75 is provided. At the position of the switching claw 75, the second circulation conveyance path 51 branches from the sheet conveyance path 121. The second circulation conveyance path 51 joins the first circulation conveyance path 77 via the image removing device 76. The image removing device 76 removes an unfixed toner image from a sheet. As a removing method, a method of removing toner by suction is preferably used.
For example, a method such as shaking off, blowing off, and scraping may be employed. The sheet fed from the sheet conveying path 121 to the second circulating conveying path 51 by rotating the switching claw 75 to change the position thereof is removed after the unfixed toner image is removed while passing through the image removing device 76. Are temporarily stored in the re-feeding device 86 via the first circulation conveyance path 77. The sheet once stored in the re-feeding device 86 is then re-supplied to the sheet conveying path 121 by the re-feeding roller 70 and the separating roller 68, and is sent to the image forming unit. The switching claw 75, the second circulating conveyance path 51, and the image removing device 76 also form a part of the circulating conveyance means.

The switchback conveyance path 124 is also provided with a switching claw 78. By rotating the switching claw 78 to change its position, the switchback conveyance path 124 is changed.
Is fed to a conveying roller 58, and the sheet is sent to a cutting device 81 by the rotation of the conveying roller 58 to be cut, and then stored in a storage section 82.

As shown in FIG. 2, the copying machine 130 has a CPU (Central Processing Unit) 101 as control means. The CPU 101 receives signals from the operation panel 102, the above-described sensors, and the like, and controls the operation of the entire copying machine including sheet conveyance based on these signals.

Next, the operation of the copying machine 130 according to the present embodiment, in particular, the operation at the time of jam clearance will be described with reference to FIGS. 3 and 4 are flowcharts showing a main routine of the entire operation of the copying machine 130 processed by the CPU 101.

In the main routine, first, an internal timer is set (step S1). Next, various input signals are processed (step S2), and various signals are output to the outside (step S3). Then, a sheet feeding process is performed (step S4), and sheets are fed to the sheet conveying path 121 from any one of the sheet feeding cassettes 97, 98, 99, and 100.

Next, it is confirmed whether or not a jam has occurred based on a signal from each sensor (step S5). If no jam has occurred (NO in step S5), a copy process is executed (step S6).

After the copying process, whether or not a jam has occurred is confirmed again based on the signal from each sensor (step S7).
If no jam has occurred (NO in step S7), the image fixing process is performed by the fixing device 74 (step S8). Next, other processing is performed (step S9). And
It is determined whether or not the timer has counted up (step S10). If the timer has already counted up, the process immediately returns to step S2. If the timer has not counted up, the process returns to step S2 after waiting until the timer has counted up. The subsequent processing is repeated.

If YES in step S5, that is, if a jam occurs, it is checked whether or not the staying sheet is before the transfer (step S301). That is, the presence of a staying sheet other than the jammed sheet that is staying in the sheet conveyance path 121 and located upstream of the pre-image forming sensor 2 in the sheet conveyance direction is confirmed.
If such a stay sheet exists (step S3
01 (YES in step S3), the position of the switching claw 6 is switched, and the staying sheet is sent to the first circulation conveyance path 77 (step S3).
02), and temporarily housed in the re-feeding device 86 (step S3)
03). Then, when the user removes the jam sheet and the jam processing end is detected (step S30).
4) The processing from step S2 described above is performed again. In the sheet feeding process at this time (step S4), first, the sheets accommodated in the sheet re-feeding device 86 are fed again to the sheet conveying path 121. Thereby, the staying sheet can be reused.
Then, when the sheet in the re-feeding device 86 runs out, the sheet is fed from the sheet feeding cassettes 97, 98, 99, 100.

In the case of NO in step S301, that is, when it is confirmed that there is a transferred staying sheet (including a sheet in the middle of transfer), it is determined whether the staying sheet has been fixed (including the case of being in the middle of fixing). It is determined whether or not it is (step S305). If the staying sheet has been fixed (YES in step S305), the position of the switching claw 93 is switched to feed the fixed staying sheet to the re-feeding conveyance path 123, and the position of the switching claw 78 is switched to resupply. The staying sheet sent from the paper transport path 123 to the switchback transport path 124 is cut by the cutting device 81 (step S306). The cut stay sheet is stored in the storage section 82. By performing the cutting process on the staying sheet that cannot be reused in this way, it is possible to prevent the printed contents from being carelessly seen by others.

In the case of NO in step S305, that is, when it is confirmed that a toner image has been transferred or a staying sheet in the middle of transfer exists between the conveyance sensor 2 before image formation and the conveyance sensor 96 before fixing, the switching claw 75 Is moved to the second circulating conveyance path 51, and the position of the switching claw 6 is changed so that the stagnated sheet upstream of the pre-image formation conveyance sensor 2 is moved to the first position.
The sheet is sent to the circulation conveyance path 77 (step S307). Second
The staying sheet sent to the circulation conveyance path 51 is removed by the image removing device 7.
After the toner image has been removed and becomes reusable in 6, the sheet is temporarily stored in the re-feeding device 86, while the retained sheet sent to the first circulating conveyance path 77 is removed by the toner removal device 76. While the image is being removed, the sheet is first stored in the re-feeding device 86 (step S309).

Thereafter, when the jam removal is detected by the user removing the jam sheet (step S).
310), the processing from step S2 described above is performed again. In the sheet feeding process at this time (step S4), first, the sheet once stored in the sheet re-feeding device 86 is
Refeed the sheet to 1. Thereby, the staying sheet can be reused. Then, when the sheet in the re-feeding device 86 runs out, the sheet is fed from the sheet feeding cassettes 97, 98, 99, 100.

After the cutting process is performed, the processes after step S310 are performed.

If YES in step S7, that is, if a jam occurs, the above-described step S30 is also performed.
Steps S311 to S310, which are the same processes as steps S1 to S310
Execute 320.

As described above, in the copying machine 130 of the present embodiment, when a jam occurs, the remaining sheets other than the jammed sheets staying in the sheet conveying path 121 are conveyed out of the sheet conveying path 121, temporarily stored, and then jammed. After the end, the sheet is fed again to the sheet conveying path 121 and sent to the image forming unit. Therefore, when a jam occurs, the user can remove the jammed sheet only and resume the copying operation.
Most of the staying sheets other than the jam sheets are re-fed to the image forming unit and reused. As a result, in comparison with a case where the user removes all the jammed sheets and other staying sheets when a jam occurs and resumes the operation of the copying machine, the waste of the sheets can be reduced, and the jam processing can be performed quickly and easily. be able to.

In the copying machine 130 of this embodiment, a re-feeding device used in the double-sided printing mode is used as a storage unit for temporarily storing the staying sheet conveyed by the first and second circulation conveyance paths 77 and 51. Although the device can be simplified and downsized by using the same as the sheet feeding device 86, the storage means may be provided separately from the refeeding device 86.

Further, in the copying machine 130 of the present embodiment,
Although the two circulation conveyance paths 77 and 51 are provided,
Alternatively, only one of the sheets 51 may be provided to accommodate the staying sheet in the sheet re-feeding device 86.

Next, another control in the copying machine 130 of this embodiment will be described. The flowchart of FIG.
The control when the circulating transport means is not used is shown. In this control, steps S1 to S10 are the same as those described with reference to FIGS.

If YES in step S5, that is, if a jam occurs, the conveyance of the sheet in the sheet conveyance path 121 is stopped (step S401). As a result, the staying sheet including the jammed sheet staying in the sheet conveying path 121 is stopped immediately. Then, the user transfers the jammed sheet causing the jam to the sheet conveying path 12.
When the jam processing end is detected by removing the sheet from Step 1 (Step S402), each conveying roller is driven to restart conveyance of the staying sheet (Step S403), and the copying process is executed (Step S6). As a result, when the operation of the copying machine 130 is resumed after the jam processing is completed, the time required for feeding the image to the image forming unit can be shortened, and the copying processing can be quickly resumed. In addition, YES in step S7
That is, even when a jam occurs, the same processing as the above-described steps S401 to S403 is performed (steps S404 to S406).

The flowcharts of FIGS. 6 and 7 show the control when the sheet size is changed before the occurrence of the jam and after the end of the jam processing. In this control, steps S1 to S
Reference numeral 10 is the same as that described with reference to FIGS.

If YES in step S5, that is, if a jam occurs, the conveyance of the sheet in the sheet conveyance path 121 is stopped (step S501). As a result, the staying sheet including the jammed sheet staying in the sheet conveying path 121 is stopped immediately. Then, the user transfers the jammed sheet causing the jam to the sheet conveying path 12.
When the end of the jam processing is detected by removing the sheet from Step 1 (Step S502), the input / output processing after the recovery from the jam processing is performed (Steps S503 and S504), and it is checked whether the sheet size is changed (Step S504). S50
5). When there is no change in the sheet size (step S50)
Then, the conveying rollers are driven to restart conveying the staying sheet (step S506), and the copying process is executed (step S6). On the other hand, if there is a change in the sheet size (YES in step S505), all the stagnated sheets stopped in the sheet conveying path 121 are discharged to the outside of the copying machine 130 by driving the respective conveying rollers and the discharging rollers (step S505). Step S507). Thereafter, the flow returns to step S2 to execute the subsequent processing to perform a copy process on a sheet of a new size. By performing such control, the copying operation can be quickly resumed when the sheet size is changed when a jam occurs.

In this embodiment, the copying machine has been described as an example. However, the sheet conveying apparatus according to the present invention can be applied not only to a copying machine but also to a printer, a facsimile, or a multifunction machine thereof.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a copying machine.

FIG. 2 is a block diagram of a control unit.

FIG. 3 is a flowchart showing a main routine of control in a control unit.

FIG. 4 is a flowchart showing a main routine of control in the control unit, and is a continuation of FIG. 3;

FIG. 5 is a flowchart showing a main routine of another control in the control unit.

FIG. 6 is a flowchart showing a main routine of still another control in the control unit.

7 is a flowchart showing a main routine of still another control in the control unit, and is a continuation of FIG. 6;

[Explanation of symbols]

6 switching claw, 51 second circulation path, 74 fixing device, 7
Reference numeral 5: switching claw, 76: image removing device, 77: first circulating transport path, 86: re-feeding device, 97, 98, 99, 100: paper feed cassette, 121: sheet transport path, 130: copying machine.

Continued on the front page (72) Inventor Akiyoshi Ueshiro 2-3-1, Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2C058 AB12 AB16 AC08 AE02 AE09 AF20 AF25 AF27 AF51 LA03 LA33 LB10 LB35 2H072 AA02 AA07 AA14 AA16 AA17 AA24 BA03 BA06 BA12 CA01 CA02 CA05 CB01 EA12 EA14 3F048 AA01 AB01 BA05 BA14 BB02 CC01 DA06 DB03 DB07 DC00 3F100 AA02 BA14 CA12 CA14 CA15 CA17 DA01 EA02 EA03

Claims (7)

[Claims] 1. A sheet conveying path extending from a sheet feeding section through an image forming section through an image fixing section, and a sheet remaining in the sheet conveying path when jam occurs other than the jammed sheet is conveyed out of the sheet conveying path. And a circulating conveyance unit for re-feeding the sheet to the sheet conveyance path after the jam processing is completed and sending the sheet to the image forming unit. 2. The circulating conveyance means includes: a first circulating path for conveying a stagnated sheet on which an image has not yet been formed by the image forming unit; and a circulating sheet for conveying the stagnated sheet conveyed through the first circulating path. 2. The sheet conveying apparatus according to claim 1, further comprising a storing unit that temporarily stores the sheet, and a feeding unit that feeds the staying sheet from the storing unit to the sheet conveying path. 3. The second circulating path for conveying a stagnated sheet in which image formation by the image forming unit is completed or in the middle and image fixing by the image fixing unit has not yet been performed. An image removing device provided in the second circulation path for removing an unfixed image from a sheet; a storage means for temporarily storing the staying sheet conveyed through the second circulation path; 3. The sheet conveying device of the image forming apparatus according to claim 1, further comprising a feeding unit that feeds the staying sheet to the sheet conveying path. 4. The sheet conveying apparatus according to claim 2, wherein said storage means also functions as a sheet re-feeding means used in a duplex printing mode. 5. A sheet for an image forming apparatus according to claim 1, further comprising cutting means for cutting a sheet of the staying sheet which has been image-fixed or is in the process of being fixed when a jam occurs. Transport device. 6. A sheet conveying path extending from a sheet feeding section through an image forming section through an image forming section, sheet conveying means for conveying a sheet in the sheet conveying path, and staying in the sheet conveying path when a jam occurs. A sheet transporting device for an image forming apparatus, comprising: a controller configured to control the sheet transporting unit so as to stop the staying sheet at that location and restart the transport of the staying sheet after the end of the jam processing. 7. The image forming apparatus according to claim 6, wherein when the sheet size is changed before the occurrence of the jam and after the end of the jam processing, the staying sheet is discharged out of the image forming apparatus. Equipment sheet transport device.