JP3919554B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for guiding a sheet to a post-processing apparatus, and relates to a sheet conveying apparatus having a function of correcting a curl formed on a sheet, and an image forming apparatus including the sheet conveying apparatus.
[0002]
[Prior art]
In an electrophotographic image forming apparatus (such as a copying machine or a printer), a toner image formed on a photosensitive drum (electrophotographic photosensitive member) as an image carrier is transferred to a sheet, and the toner image transferred sheet is fixed. Through the apparatus, the toner is fixed on the sheet surface to form a permanent image. Note that silicon oil is generally applied to the sheet passing through the fixing device so that the toner and the sheet do not adhere to the fixing roller.
[0003]
Also known are sheets having a sheet post-processing device that sorts sheets after image fixing by a sorter, a finisher or the like. 2. Description of the Related Art A sheet conveyance device (hereinafter referred to as a buffer unit) for conveyance to a processing apparatus is known.
[0004]
An electrophotographic image forming apparatus has a full color mode in which four color toners are placed on a sheet as in a full color machine, a single color mode in which image formation is performed with only one color toner, and two or three color toners on the sheet. There are two-color and three-color modes for forming an image on the screen.
[0005]
In general, when a toner image is placed on one surface of a sheet and is fixed by passing through a fixing roller that applies pressure and heat, the sheet is curled toward the image surface on which the toner image is placed.
[0006]
However, when the sheet that has passed through the fixing device is stored in a sheet post-processing device such as a sorter or finisher, or a paper discharge tray, if the sheet is curled, it is likely to cause a conveyance failure such as a jam, There is a possibility that the function of a sheet post-processing apparatus such as a finisher cannot be sufficiently achieved.
[0007]
Therefore, in general, a function for correcting curl formed on a sheet is provided between the image forming apparatus main body (fixing apparatus thereof) and a sheet post-processing apparatus such as a sorter or a finisher, or a paper discharge tray. Provided buffer unit is arranged.
[0008]
This buffer unit may be provided integrally with the image forming apparatus, or may be provided separately between the apparatus main body and the sheet post-processing apparatus.
[0009]
Next, with reference to FIG. 14 and FIG. 15, the sheet conveying apparatus and the image forming apparatus according to the related art will be described in more detail. For convenience of explanation, the same components as those in the drawings referred to in the description of a sheet conveying apparatus and an image forming apparatus according to an embodiment of the present invention to be described later are denoted by the same reference numerals, and overlapping portions will be described. Are omitted as appropriate.
[0010]
As shown in FIG. 14, an image forming apparatus main body 400 for forming an image on a sheet, a sheet post-processing apparatus (hereinafter referred to as a sorter 200) having a function of sorting sheets after image formation, and these A sheet conveying device (hereinafter referred to as a buffer unit 100) disposed therebetween.
[0011]
In addition, although the example of illustration takes the structure which has arrange | positioned the separate apparatus, respectively, these may be provided integrally.
[0012]
The buffer unit 100 has a function of switching so that the sheet conveyed from the image forming apparatus main body 400 is conveyed as it is or is reversed and conveyed.
[0013]
The buffer unit 100 also includes correction means 104 and 110 for correcting the curl formed on the conveyed sheet.
[0014]
Here, the correcting means 104 is for correcting when curled upward, while the correcting means 110 is for correcting when curled downward.
[0015]
Then, in order to curl to the higher image density of the formed image on both sides of the sheet, one of the correction means 104 and 110 described above is operated in accordance with the image density information.
[0016]
The sorter 200 also includes an uppermost non-sorting bin B0 and a plurality of sorting bins B1 to B20 provided below the uppermost non-sorting bin B0, and sorts the conveyed sheets by collation or grouping and discharges them. It has a function.
[0017]
[Problems to be solved by the invention]
However, in the case of the prior art as described above, the following problems have occurred.
[0018]
As described above, conventionally, when the sheet S sent to the sheet post-processing apparatus such as the sorter 200 has the correction means serving as the curl removing means in the buffer unit 100, regardless of the processing method in the sorter, The correction means is controlled by the difference between both sides of the image density on the sheet S.
[0019]
However, when curling is performed with the difference in both sides of the image density in this way, the sheet S undulates when the sheets S are placed in the sort bins B1 to B20 of the sorter 200 in the group mode or the stack mode (for example, the sort bin shown in FIG. 15). There is a problem that a paper jam (hereinafter referred to as a jam) occurs due to the sheet loaded on B7).
[0020]
This point will be described in more detail.
[0021]
In the group mode or the stack mode, the sheets S are continuously discharged to the sort bin.
[0022]
Here, the sheet S is curled in the buffer unit 100 (up curl by the correcting means 104 in FIG. 15), passes through the sort path 205, and is discharged by the paper discharge roller 206.
[0023]
At this time, immediately after the sheet S is corrected, the curl is on the side opposite to the curl before correction. That is, in the example shown in FIG. 15, the upper curl is corrected so as to remove the upper curl.
[0024]
Since the sheets S continuously come into the sort bin, the next sheet S is discharged before the curl (upper curl) of the previously discharged sheet S by the toner grows. Are continued to be stacked in the sort bin, and the height of the sheet discharge surface is increased. As shown in FIG. 15, a part of the sheet S comes into contact with the lower surface of the upper sort bin B6 and enters the sort bin of the sheet S to be discharged next. There was a case where jam occurred due to obstructing the discharge of water.
[0025]
Further, even when there is a space above, such as a normal discharge tray or sorting tray that is not a sort bin, the sheet S is continuously formed on the sheet on which the curl formed by the curl correcting means remains. When the sheet is discharged, jamming may occur due to interference between the sheet stacked on the tray and the sheet being discharged.
[0026]
SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus and an image forming apparatus that are capable of preventing a jam caused by a sheet discharged in a post-processing apparatus. There is to do.
[0027]
[Means for Solving the Problems]
In order to achieve the above object, in the sheet conveying apparatus of the present invention, Form a curl in the opposite direction to the curl that was formed on the sheet before curl correction, Correcting means that corrects curl formed on the sheet transported in the transport path that guides the sheet to the post-processing device is not performed under certain conditions, or corrected by reducing the degree of correction The operation was performed.
[0028]
In other words, if a problem such as a jam occurs when the correction operation is performed as usual, such a problem can be prevented by not performing the correction operation or by performing the correction operation with a reduced degree of correction. I tried to prevent it.
[0029]
Here, the specific conditions may include the following cases.
[0030]
First, the post-processing apparatus having a plurality of bins continuously discharges sheets to sort bins other than the uppermost non-sort bin.
[0031]
Second, the group mode in which the post-processing apparatus having a plurality of bins continuously discharges sheets to a specific sort bin other than the uppermost non-sort bin is selected.
[0032]
Third, when the post-processing apparatus having a plurality of bins exceeds the number of sheets that can be stacked in the uppermost non-sort bin, the stack mode for discharging sheets to a sort bin other than the non-sort bin is selected.
[0033]
Also, performing the correction operation with a lowering of the correction level is more effective than performing the correction operation with a lower correction level than when discharging the sheet to the non-sort bin, or when discharging the sheet intermittently. This includes performing a corrective action at a reduced level.
[0034]
Note that the sheet conveying apparatus may include a reversing unit that reverses the sheet conveyed from the upstream side and guides the reversed sheet to the post-processing apparatus.
[0035]
In addition, the sheet conveying apparatus can be provided integrally with the image forming apparatus, or can be provided separately from the image forming apparatus. Further, the sheet conveying device can be provided integrally with the post-processing device, or can be provided separately from the post-processing device. Furthermore, the sheet conveying apparatus, the image forming apparatus, and the post-processing apparatus can be provided integrally.
[0036]
Here, in the image forming apparatus, it is preferable that four image forming units that form images of different colors are arranged in series and a full color image can be formed.
[0037]
In addition, when the number of sheets loaded into the sort bin other than the top non-sort bin among the plurality of bins provided in the post-processing device reaches the maximum number of sheets loaded, or when sheet discharge stops regardless of the number of loaded sheets. The stacked sheets may be clamped by the sort bin and the bin one above the sort bin.
[0038]
Further, the post-processing apparatus may have a stack function for stacking a large number of sheets.
[0039]
Further, the post-processing apparatus may have a function of collating sheets.
[0040]
The operation by the correction means described above can be controlled using the control means.
[0048]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.
[0049]
In the following description, a full-color copying machine will be described as an example of an image forming apparatus. However, it is needless to say that the present invention is not limited to this and can be applied to a full-color printer, a monochrome copying machine, a monochrome printer, and the like. Yes.
[0050]
(First embodiment)
With reference to the flow chart shown in FIG. 1 and the control block diagram shown in FIG. 13, the sheet conveyance according to the first embodiment of the present invention will be described with reference to FIGS. The apparatus and the image forming apparatus will be described.
[0051]
FIG. 1 is a flowchart showing an operation flow of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the sheet conveying apparatus and the post-processing apparatus according to the embodiment of the present invention. FIG. 14 is a schematic cross-sectional view of the image forming apparatus. FIG. 13 is a control block diagram of the image forming apparatus.
[0052]
A document (not shown) is placed on the automatic document feeder DF, and a user presses a start button (not shown) (S1).
[0053]
Then, the sheet S is fed from the cassettes la and lb (S5). The sheet S waits at the registration roller 2 in order to take timing with the image forming unit. In the meantime, the document is conveyed onto the document table 3, scanned by the optical system 4 and read into the CCD, and the image information is converted into an electrical signal (S2).
[0054]
Here, the image information (electrical signal) is decomposed into components of a yellow image (Y), a magenta image (M), a cyan image (C), and a black image (Bk).
[0055]
The image signal converted into an electrical signal is sent to a laser / light emitting device (not shown) to control light emission. Laser light corresponding to the image signal is scanned by the polygon mirror 16 and irradiated to the photosensitive drums 5Y, 5M, 5C, and 5Bk of the image recording unit by the mirror unit 11 to form latent images (S3).
[0056]
The photosensitive drums 5Y, 5M, 5C, and 5Bk rotate in the right direction in the figure, and after the surfaces of the photosensitive drums 5Y, 6M, 6C, and 6Bk are uniformly charged by the primary chargers 6Y, 6M, 6C, and 6Bk, An image is formed.
[0057]
The latent images formed on the photosensitive drums 5Y, 5M, 5C, and 5Bk are visualized as toner images corresponding to the respective colors by the developing devices 17Y, 17C, 17M, and 17Bk, respectively (S4).
[0058]
On the other hand, the sheet S waiting on the registration roller 2 is transported while being electrostatically attracted by the transfer belt 9 after being timed with the above-described image signal, and on the photosensitive drums 5Y, 5M, 5C, and 5Bk. The toner images are sequentially transferred onto the sheet S for each color in a superimposed manner by the transfer chargers 7Y, 7M, 7C, and 7Bk, respectively, and full-color images are formed with the respective black, yellow, magenta, and cyan toners (S7). ).
[0059]
Note that the toner remaining on the photosensitive drum without being transferred is cleaned by the cleaning devices 8Y, 8M, 8C, and 8Bk, respectively.
[0060]
The sheet S to which the development (toner image) has been transferred is then conveyed to the fixing device 10, and the toner image is melted and fixed on the surface (S 8). It is sent into the buffer unit 100 which is a feature of the embodiment of the invention (S9).
[0061]
The sheet S sent into the buffer unit 100 is further sent to a sorter 200 as a post-processing device that performs collation and grouping processing, and the image forming process is completed.
[0062]
The sorter 200 includes a carry-in unit 202 for carrying in the sheet S discharged from the buffer unit 100 and an entrance roller 201 for drawing in the carried-in sheet S.
[0063]
When the sheet S is not sorted (sorted), the sheet S is discharged to the uppermost non-sort bin B0 by the discharge roller 203, and when the sheet S is sorted, the sheet S is sorted to the sort bins B1 to B20 by the discharge roller 206 through the sort path 205. Sort and discharge.
[0064]
As the main sorting function of the sorter 200, there are a sort mode, a group mode, a stack mode, and the like.
[0065]
In the sort mode, the sheets are discharged one by one in the order of sort bins B1, B2,... B19, B20. Thereafter, the sheets are discharged one by one in the order of B20, B19... B2, B1. Such reciprocation is repeated to collate. That is, the paper is intermittently discharged into one sort bin.
[0066]
On the other hand, in the group mode and the stack mode, the number of sheets that can be stacked on one of the sort bins B1, B2,.
[0067]
The group mode is a mode that discharges paper to a specific sort bin. In the stack mode, the sheet is automatically sent to the sort bin when the number of continuous paper discharges specified at the start exceeds the non-sort bin load regulation number. It is a mode to load.
[0068]
The digital color copying machine may be used as a system printer in addition to the copying machine alone. At this time, there is a back surface discharge function that optimizes the page order of the sheet S.
[0069]
With reference to FIG. 7, the conveyance path | route in the buffer unit 100 is demonstrated. FIG. 7 is a schematic diagram showing a sheet conveying path in the sheet conveying apparatus (buffer unit) according to the embodiment of the present invention.
[0070]
In FIG. 7, on the downstream side of the conveying roller 101 on the sheet conveying path 109 (see FIG. 14), a branching portion 106 including a branching member (reversing means) 102 is disposed, and the branching member 102 is a reverse solenoid. (Not shown) can be switched between a state in which the sheet S is guided to the paper discharge roller 105 and a state in which the sheet S is reversed to the reverse conveyance path 107.
[0071]
When the sheet S is discharged from the back side, the branching member 102 forms a path toward the reverse conveyance path 107 as shown in FIG.
[0072]
A reversing roller 103 that can rotate forward and reverse is disposed in the reversing conveyance path 107. The reversing roller 103 is controlled in rotation amount and direction by a reversing motor (not shown) formed of a stepping motor.
[0073]
At the time of paper discharge at the back side, the sheet S passes through the branching member 102 of the branching portion 106 in the state of FIG. 7A and is guided into the reverse conveyance path 107, and the rear end of the sheet is shown in FIG. 7B. Thus, after passing through the branch member 102, the sheet S temporarily stops. The passage of the sheet S is detected by the sensor S1.
[0074]
Thereafter, the branch member 102 is controlled to switch to the paper discharge roller 105 side (FIG. 7C). Further, the reverse roller 103 rotates in the reverse direction and reversely conveys the sheet S. As shown in FIG. 7C, the conveyed sheet S is conveyed to the paper discharge roller 105 side (FIG. 1) via the branch member 102 and further discharged out of the buffer unit 100 by the paper discharge roller 105. Is done.
[0075]
Through the above-described operation process, the sheet S can be conveyed with the front and back surfaces of the sheet S reversed. In this way, by discharging the sheet S from the back side, the discharged sheet S is aligned with the normal order pages 1, 2,... From the bottom with the image surface facing downward. As a result, even when the image forming apparatus main body 400 is used as an output device (printer) of an external device, it is possible to prevent occurrence of page misalignment of discharged sheets in advance.
[0076]
Another important role of the buffer unit 100 is the curl correction function of the sheet S.
[0077]
Here, the correcting means 104 and 110 functioning as the curl removing means of the buffer unit 100 will be described with reference to FIG. FIG. 8 is an explanatory view for explaining the mechanism of curl removal.
[0078]
The correction means 104 and 110 are sponge rollers 311 and 321 in which a material such as urethane rubber is wound around the outside of the metal shaft, metal rollers 312 and 322 provided at opposite positions thereof, and a backup that supports the metal rollers 312 and 322, respectively. Members 313 and 323.
[0079]
When the sheet S passes, the sponge rollers 311 and 321 enter the metal rollers 312 and 322 by cam control. Thus, the curl of the sheet S is corrected by forming a nip and passing the sheet S through the nip portion.
[0080]
Further, the amount of penetration of the sponge rollers 311 and 321 is divided into several stages by using an eccentric cam (not shown) or the like, so that the curl correction ability can be adjusted.
[0081]
FIG. 13 is a control block diagram for controlling the curl correcting ability of the curl correcting means 104 and 110. The first motor 331 and the second motor 332 rotate eccentric cams that move the sponge rollers 311 and 321 respectively. When the first motor 331 is rotated by the control circuit 401 (control means), the first eccentric cam (not shown) rotates, and the correction means 104 is moved by moving the rotating shaft of the sponge roller 311 closer to or away from the metal roller 312. Adjust curl correction ability. When the rotation shaft of the sponge roller 311 is moved farthest from the metal roller 312, the curl correcting action is lost.
[0082]
Similarly, when the second eccentric cam is rotated by the second motor 332, the rotation shaft of the sponge roller 321 is moved, and the curl correcting ability of the curl correcting means 110 is adjusted or invalidated.
[0083]
The sponge rollers 311 and 321 may be moved using actuators 341 and 342 such as solenoids in addition to the motor.
[0084]
In FIG. 13, a third motor 333 is a driving means for moving the position of a tray of a stacking means such as a processing tray or a sorter.
[0085]
An operation panel 410 is an input means for an operator to input processing instructions such as the number of copies, sort mode, group mode, stack mode, and staple mode. The control circuit 401 controls the first motor 331, the second motor 332, the third motor 333, the stapling means 1340 and the like according to the number of copies and the mode input by the operation panel 410.
[0086]
Further, processing instructions and image information for image formation may be input from the computer terminal 601 via the network 600 such as a communication cable, and these are also a kind of input means.
[0087]
FIG. 8A illustrates the control when the upper surface image density of the sheet S is higher than the lower surface image density when the sheet S is conveyed to the correction means 104, 110. In this case, the upper curl is removed. The sponge roller 311 of the correcting means 104 for taking the sheet intrudes, but the correcting means 110 for taking the lower curl is not operated and the sheet S is conveyed.
[0088]
This makes it possible to correct the upper curl formed on the sheet.
[0089]
On the other hand, FIG. 8B illustrates the control when the lower surface image density of the sheet S is higher than the upper surface image density when the sheet S is conveyed to the correction means 104, 110. The sponge roller 321 of the correction means 110 for removing the curl is inserted, but the correction means 104 for removing the upper curl is not operated, and the sheet S is conveyed.
[0090]
This makes it possible to correct the lower curl formed on the sheet.
[0091]
As described above, regardless of whether the image is a single-sided image or a double-sided image, the image density on the upper surface of the sheet S to be discharged is high. The paper is corrected, and the curl is corrected by the correction means 110 for removing the lower curl at the time of reverse paper discharge.
[0092]
Conversely, when the image density on the lower surface of the sheet S discharged from the apparatus main body 400 is high and straight discharge is performed, the curl is corrected by the correcting means 110 for taking the lower curl, and the reverse discharge is performed. Corrects the curl by the correcting means 104 for taking the upper curl.
[0093]
Therefore, the correcting means 104 for taking the upper curl and the correcting means 110 for taking the lower curl do not operate simultaneously.
[0094]
As described above, after the curl of the sheet S is corrected, the sheet S is fed into the sorter 200 by the paper discharge roller 105.
[0095]
Next, the operation control of the buffer unit 100 that is a feature of the present embodiment will be described in more detail.
[0096]
When the group mode is selected for the sheet S (S10) that is straight or reversely conveyed in the buffer unit 100 (S21, YES), the control means drives the first motor 331 and the second motor 332. Thus, the sheet S is sent to the sorter 200 as it is without performing the correction operation by the correction means 104 and 110.
[0097]
On the other hand, when the mode is other than the group mode (S21, NO), the curl is removed by performing the correction operation by any of the correction units 104 and 110 (S11), and the curl correction of the sheet S is performed.
[0098]
Accordingly, the correction operation is not performed when the sheet is continuously discharged to any one of the sort bins B1, B2,... B19, B20 specified in the group mode. The curl due to the operation is not formed, and the next sheet is continuously discharged before the curl grows with the toner. Therefore, it is possible to prevent sheet jam caused by the curl.
[0099]
Accordingly, the state of the sheets S stacked continuously in the sort bin can be kept good.
[0100]
By performing the control as described above, as shown in FIG. 3, the sheets S are stacked in the sort bins B1 to B20 (sort bin B7 in the illustrated example) during the group processing without causing jamming of the sheets S. Consistency can be increased.
[0101]
Further, in the sort bins B1 to B20, when the number of sort bins in which the sheets to be discharged are stacked reaches the maximum number of stacked sheets, or when the sheet passing is interrupted regardless of the number of stacked sheets, the sort bin is moved up by one. By closing (sorting) the stacked sheets with the upper and lower sort bins, the curling growth of the top sheet S among the stacked sheets in the sort bin can be prevented. And better stackability can be maintained.
[0102]
(Second Embodiment)
FIG. 2 shows a second embodiment of the present invention. In the present embodiment, a new configuration is added to the control flow in the first embodiment, and only the characteristic part will be described in detail.
[0103]
The configuration of the apparatus itself is the same as that described with reference to FIGS. 3, 8, 13, and 14 in the first embodiment, and the description thereof is omitted.
[0104]
FIG. 2 is a flowchart showing an operation flow of the image forming apparatus according to the second embodiment of the present invention. The same parts as those in the flowchart of FIG. 1 referred to in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
[0105]
In the present embodiment, in addition to the control flow in the first embodiment, if the number of continuous sheets to be passed is a certain value X or more at the start (S1) (S31, YES), the control means 400 The first motor 331 and the second motor 332 are controlled to prohibit curl removal, and when it is less than X (S31, NO), curl removal is performed.
[0106]
Here, the constant value X is the maximum number of sheets that can be accommodated in the non-sort bin B0.
[0107]
In other words, if the number of continuous sheets to be passed is specified as X or more and started, the sorter 200 normally enters a stack mode in which the discharged sheets are sent to the sort bin because the number of sheets cannot be loaded in the non-sort bin B0.
[0108]
In the stack mode, the sheets S that cannot be stacked on the sort bins B1 to B20 after being continuously discharged to the sort bins are stacked on the non-sort bin B0. Therefore, the stack bins have the same stacking conditions as the group mode.
[0109]
Accordingly, when the sheet S is discharged to the sorter 200 in the stack mode, the stacking alignment can be improved without causing the sheet S to jam as described above.
[0110]
(Third embodiment)
4 and 5 show a third embodiment of the present invention. In the present embodiment, a new configuration is added to the control flow in the second embodiment, and only the characteristic part will be described in detail.
[0111]
FIG. 4 is a schematic cross-sectional view of the image forming apparatus. Note that the image forming apparatus itself shown in this figure is the same as that shown in FIG. 14, but clearly shows the state of the discharged sheet, which is a feature of this embodiment. FIG. 5 is a flowchart showing an operation flow of the image forming apparatus according to the third embodiment of the present invention. The same parts as those in the flowcharts of FIGS. 1 and 2 referred to in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
[0112]
In FIG. 4, reference numeral 19 denotes a count sensor that counts the number of sheets S to be passed.
[0113]
In the present embodiment, in the control flow in the first embodiment or the second embodiment, the count sensor 19 that counts the number of sheets S to be passed in a state where curl removal is prohibited is continuously performed. The difference is that curl removal is started when the count reaches Y or more (S41, YES).
[0114]
Here, the count value Y in FIG. 5 is the number of sheets S that can be stacked in total on the sort bins B1 to B20 of the sorter 200. For example, assuming that 50 sheets of A4 size paper can be stacked per sort bin, Y = 1000. As a result, the sheet S is decurled (S11) from the next 1001st sheet.
[0115]
That is, as described above, in the case of the stack mode, when sheets cannot be stacked in the sort bins B1 to B20 of the sorter 200, the sheets are stacked in the non-sort bin B0.
[0116]
In this case, when correction is not performed for curl removal with respect to the sort bins B1 to B20 and the non-sort bin B0, as described above, it is suitable for the sheets stacked on the sort bins B1 to B20. However, the sheet stacked on the non-sort bin B0 will have a curling formation with toner thereafter, so that the stacking alignment is deteriorated.
[0117]
Therefore, in the present embodiment, by correcting the sheets S stacked in the non-sort bin B0, all the sheets S stacked in the non-sort bin B0 are decurled and the sheets on the non-sort bin B0 are decurled. S stacking consistency can be improved.
[0118]
Therefore, even if a large number of sheets S are continuously discharged to the sorter 200, as shown in FIG. 4, the sheets S stacked in the sort bins B1 to B20 and the non-sort bin B0 can both maintain high alignment stackability. .
[0119]
(Fourth embodiment)
FIG. 6 shows a fourth embodiment of the present invention. In each of the above embodiments, the case where the image forming apparatus main body and the sheet conveying apparatus (buffer unit) are connected as separate apparatuses to configure the system has been described. However, in the present embodiment, these are integrated. Shown when configured.
[0120]
FIG. 6 is a schematic sectional view of an image forming apparatus according to the fourth embodiment of the present invention.
[0121]
As shown in the figure, in the present embodiment, the image forming apparatus 300 is not different from the structures in the above embodiments except that the image forming apparatus main body and the buffer unit are integrated.
[0122]
Moreover, what is necessary is just to apply any of the said 1st-3rd embodiment regarding a control flow. Thereby, the effect equivalent to said each embodiment can be acquired.
[0123]
(Fifth embodiment)
A post-processing apparatus 1300 according to the fifth embodiment of the present invention will be described with reference to FIGS. 9 and 10.
[0124]
[Overall configuration of post-processing equipment]
In FIG. 10, a post-processing apparatus 1300 receives a sheet discharged from the image forming apparatus from an entrance roller pair 1302 and conveys the sheet into the interior. A conveying roller pair 1303 is provided downstream of the inlet roller pair 1302, and a sheet detection sensor 1331 is provided between the inlet roller pair 1302 and the conveying roller pair 1303.
[0125]
A punch unit 1350 is provided downstream of the conveyance roller pair 1303, and a large conveyance roller 1305 and pressing rollers 1312, 1313, and 1314 that press and convey the surrounding sheets are disposed downstream of the punch unit 1350.
[0126]
The switching flapper 1311 switches between the non-sort path 1321 and the sort path 1322. A switching flapper 1310 at the entrance of the sort path 1322 switches between the sort path 1322 and the buffer path 1323 for temporarily storing sheets.
[0127]
A transport roller 1306 is provided in the sort path 1322. On an intermediate tray (hereinafter referred to as a “processing tray”) 1313 as a stacking tray disposed downstream of the sort path 1322, temporary stacking and alignment of sheets, stapling by a stapling unit 1340, and the like can be performed.
[0128]
A discharge roller 1307 at the exit of the sort path 1322 discharges the sheet onto the processing tray 1313. The upper bundle discharge roller 1318b is supported by the swing guide 1315. When the swing guide 1315 moves to the closed position, the upper bundle discharge roller 1318b cooperates with the lower bundle discharge roller 1318a disposed on the processing tray 1313 to remove the sheet on the processing tray 1313. The bundle is conveyed and discharged onto the stack tray 1320.
[0129]
That is, the swing guide 1315 is inclined, and the lower bundle discharge roller 1318a and the upper bundle discharge roller 1318b form a roller pair to convey the sheets on the processing tray 1313 in a bundle.
[0130]
Next, with reference to the flowchart shown in FIG. 9, the flow of operation of each device according to the present embodiment will be described. Also, the same symbols as those in the first embodiment indicate the same components, and thus the description thereof is omitted.
[0131]
The difference between the flowchart of this embodiment and the flowchart of the first embodiment is S44 and S15.
[0132]
In S44, curl removal of the buffer unit 100 is prohibited when the number of continuous sheets or the cumulative number of sheets passed reaches a predetermined number N. Accordingly, the correction operation is not performed when the sheets S stacked on the processing tray 313 or the stack tray 320 of the post-processing apparatus 300 are continuously discharged N or more sheets. The curl due to the operation is not formed, and the next sheet is continuously discharged before the curl grows with the toner. Therefore, it is possible to prevent the sheet jam and the fall due to the curl.
[0133]
Therefore, the state of the sheets S stacked continuously on the processing tray 313 and the stack tray 320 can be kept good.
[0134]
By performing the control as described above, stacking alignment without causing jamming or dropping of the sheet S on the processing tray 1313 or the stack tray 1320 of the post-processing apparatus 1300 during continuous sheet passing more than predetermined. Can increase the sex.
[0135]
Further, when the post-processing apparatus 1300 of the present embodiment is the stacker 500 capable of stacking a large number of sheets S in FIG. 11 or the simple sheet stacking tray 600 in FIG. 12, the same effect can be obtained. .
[0136]
Further, in each of the above embodiments, regarding the curl prohibition (S22) in the flowcharts, when the correction means of the buffer unit has several levels of correction ability (function capable of changing the correction degree), normal intermittent paper passing A similar effect can be obtained by controlling the curl correction ability to be one step or several steps lower than the curl correction ability step determined by the image density at the time.
[0137]
【The invention's effect】
As described above, in the present invention, when sheets are continuously discharged to the sort bin and the stacking tray provided in the post-processing apparatus, the correction operation by the correction means is not performed, or the correction is not performed. Since the correction operation is performed at a reduced level, curling on the sheet due to the correction operation is not formed, and jamming due to this can be prevented.
[0138]
This can be suitably applied when the group mode is selected or when the stack mode is selected.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an operation flow of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing a flow of operations of an image forming apparatus according to a second embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of a sheet conveying apparatus and a post-processing apparatus according to an embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of an image forming apparatus.
FIG. 5 is a flowchart showing an operation flow of an image forming apparatus according to a third embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view of an image forming apparatus according to a fourth embodiment of the present invention.
FIG. 7 is a schematic diagram illustrating a sheet conveyance path in the sheet conveyance apparatus according to the embodiment of the present invention.
FIG. 8 is an explanatory diagram illustrating a mechanism for curling a sheet.
FIG. 9 is a flowchart showing a flow of operation of an image forming apparatus according to a fifth embodiment of the present invention.
FIG. 10 is a schematic cross-sectional view of a post-processing apparatus according to a fifth embodiment of the present invention.
FIG. 11 is a schematic cross-sectional view of a post-processing apparatus according to a fifth embodiment of the present invention.
FIG. 12 is a schematic cross-sectional view of a post-processing apparatus according to a fifth embodiment of the present invention.
FIG. 13 is a control block diagram of first to fifth embodiments of the present invention.
FIG. 14 is a schematic cross-sectional view of an image forming apparatus.
FIG. 15 is an explanatory diagram for explaining a problem of a sheet conveying apparatus according to a conventional technique.
[Explanation of symbols]
5Y, 5M, 5C, 5Bk photosensitive drum
19 Count sensor
100 buffer units
102 Branch member
103 Reverse roller
104,110 Correction means
105 Paper discharge roller
106 Branch
107 Reverse transfer path
109 Sheet transport path
200 Sorter
201 Inlet roller
203, 206 Discharge roller
205 Sort path
300 Image forming apparatus
311 and 321 sponge rollers
312 and 322 metal rollers
313,323 Backup member
400 (Image formation) Device body
401 control circuit
500 Stacker
600 sheet stacking tray
1300 Post-processing equipment
B0 non-sort bin
B1-B20 sort bin

Claims (13)

A conveyance path for guiding the sheet to a post-processing apparatus having a function of sorting and discharging the sheet into a plurality of bins;
In a sheet conveying apparatus comprising: a correcting means for correcting a curl formed on a sheet conveyed in the conveying path by forming a curl in a direction opposite to the curl formed on the sheet before the curl correction . ,
When the post-processing device continuously discharges sheets to the sort bins other than the uppermost non-sort bin among the plurality of bins, either the correction operation by the correction means is not performed, or the non-sort bin A sheet conveying apparatus that performs a correcting operation with a lower correction level than in the case of discharging a sheet. A conveyance path for guiding the sheet to a post-processing apparatus having a function of sorting and discharging the sheet into a plurality of bins;
In a sheet conveying apparatus comprising: a correcting means for correcting a curl formed on a sheet conveyed in the conveying path by forming a curl in a direction opposite to the curl formed on the sheet before the curl correction . ,
When a group mode for continuously discharging sheets to a specific sort bin other than the uppermost non-sort bin among the plurality of bins is selected, the correction operation by the correction unit is not performed, or A sheet conveying apparatus that performs a correction operation with a lower degree of correction than when discharging a sheet to a non-sort bin. A conveyance path for guiding the sheet to a post-processing apparatus having a function of sorting and discharging the sheet into a plurality of bins;
In a sheet conveying apparatus comprising: a correcting means for correcting a curl formed on a sheet conveyed in the conveying path by forming a curl in a direction opposite to the curl formed on the sheet before the curl correction . ,
When the number of sheets that can be stacked in the uppermost non-sort bin among the plurality of bins is exceeded, when the stack mode for discharging sheets to a sort bin other than the non-sort bin is selected, the correction operation by the correction unit is not performed. Alternatively, the sheet conveying apparatus performs the correcting operation with a lower correction level than in the case of discharging the sheet to the non-sort bin.   4. The sheet conveying apparatus according to claim 1, further comprising a reversing unit that reverses the sheet conveyed from the upstream side and guides the reversed sheet to the post-processing apparatus. Image forming means for forming an image on a sheet to be conveyed;
The sheet conveying apparatus according to any one of claims 1 to 4, wherein the sheet on which an image is formed by the image forming unit is further conveyed downstream.
An image forming apparatus comprising: a post-processing device having a function of sorting and discharging sheets conveyed by the sheet conveying device into a plurality of bins.   6. The image forming apparatus according to claim 5, wherein four image forming units that form images of different colors are arranged in series to form a full color image.   Among the plurality of bins provided in the post-processing device, when the number of stacked sheets other than the uppermost non-sorted bin reaches the maximum number of stacked sheets, or when the discharge of sheets is stopped regardless of the number of stacked sheets, The image forming apparatus according to claim 5, wherein the stacked sheets are sandwiched between the sort bin and a bin one above the sort bin. A post-processing apparatus having a stacking tray for stacking sheets and having a function of stacking sheets on the stacking tray is provided with a conveyance path for guiding the sheet and a curl opposite to the curl formed on the sheet before the curl correction. In a sheet conveying apparatus comprising: a correction unit that corrects curl formed on a sheet that is formed on a sheet and conveyed in the conveyance path;
When the post-processing device continuously discharges sheets onto the stacking tray, it does not perform the correction operation by the correction means, or the correction degree is higher than when the sheets are discharged intermittently. A sheet conveying apparatus that performs a correction operation by dropping the sheet.   9. The sheet conveying apparatus according to claim 8, wherein the post-processing apparatus has a stack function for stacking a large number of sheets.   The sheet conveying apparatus according to claim 8, wherein the post-processing apparatus has a function of collating sheets. A sheet stacking sheet, a conveyance path for guiding the sheet to the stacking tray, a function of discharging the sheet to the stacking tray, and a curl opposite to the curl formed on the sheet before curl correction is formed on the sheet. And a sheet conveying apparatus provided with a correcting means for correcting curl formed on the sheet conveyed in the conveying path,
When the sheets are continuously discharged onto the stacking tray, the correction operation by the correction unit is not performed, or the correction operation is performed with a lower degree of correction than when the sheets are discharged intermittently. A sheet conveying apparatus. A stacking tray for stacking sheets;
Conveying means for conveying sheets to the stacking tray;
A correction means for correcting the curl of the sheet conveyed by the conveying means by forming a curl in the opposite direction to the curl formed on the sheet before the curl correction ;
In the case where a predetermined number of sheets or more are continuously conveyed to the stacking tray by the conveying unit, the correction by the correcting unit is not performed, or the case where less than a predetermined number of sheets are continuously discharged. And a control means for controlling the correction means so as to perform the correction operation weakly.   The sheet conveying apparatus according to claim 12, further comprising a stapling unit that binds the bundle of sheets stacked on the stacking tray.

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