JP6968577B2 - Sheet transfer device - Google Patents

Description

The present invention relates to a sheet transport device for transporting sheets.

In general, in an image forming apparatus for forming an image on a sheet such as a printer, there is known a problem of double feeding in which a plurality of sheets are fed in a stacked state when the sheets are fed. When double feeding occurs, the sheets transported in an overlapping manner (hereinafter, also referred to as double feeding sheets) are clogged in the sheet transport path and cause sheet jam. Further, even if the sheet jam does not occur, a blank sheet on which no image is formed is mixed in the deliverable. In particular, when binding or stapling a sheet on which an image is formed, there is a problem that a blank sheet intervenes in the bound or stapled deliverable.

Therefore, conventionally, an escape transport path is provided so as to branch from the middle of the sheet transport path, and the double feed sheet is discharged to the escape tray via the escape transport path (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-42469

In this way, if the double feed sheet is discharged to the escape tray via the escape transport path, it is possible to prevent the double feed sheet from being mixed into the deliverable. Further, since the double feed sheet can be processed without stopping the operation of the printer when the double feed occurs, the down time caused by the double feed sheet processing can be shortened.

On the other hand, when a sheet jam occurs in the escape transfer path and the sheet causing the sheet jam is a long sheet long in the sheet transfer direction, a part of the sheet still remains on the sheet transfer path. The seat may stop. If the user forcibly pulls the sheet in which the sheet is jammed in this state, a part of the sheet may be torn and a part of the long sheet may be left behind on the sheet transport path.

Therefore, an object of the present invention is to provide a sheet transfer device capable of appropriately processing a double feed sheet according to a situation.

One aspect of the present invention is a sheet loading section for loading a sheet, a sheet feeding means for feeding the sheet loaded on the sheet loading section, and a double feeding of a sheet fed from the sheet feeding means. The double feed detecting means for detecting, the double feed sheet discharging section in which the sheet for which double feed is detected by the double feed detecting means is discharged via the escape transport path branched from the middle portion of the sheet transport path, and the double feed sheet discharging section. When the double feed is detected by the feed detection means, the first mode in which the sheet in which the double feed is detected is discharged to the double feed sheet discharging unit via the escape transport path and the sheet in which the double feed is detected are displayed. The control means is provided with a control means capable of executing a second mode of stopping on the sheet transport path without discharging the double feed sheet to the double feed sheet discharging unit, and the control means transfers the sheet of the sheet in which the double feed is detected. When the length in the direction is shorter than the predetermined length corresponding to the length of the escape transport path, the first mode is executed, and the length of the sheet in which double feed is detected in the sheet transport direction is the predetermined length. The sheet transport device is characterized in that the second mode is executed in the above cases.
Further, one aspect of the present invention is the weight of a sheet loading section for loading a sheet, a sheet feeding means for feeding the sheet loaded on the sheet loading section, and a sheet fed from the sheet feeding means. A double feed detecting means for detecting feeding, a double feeding sheet discharging section in which a sheet for which double feeding is detected by the double feeding detecting means is discharged via an escape transport path branched from a middle portion of the sheet transport path, and a double feed sheet discharging section. When the double feed is detected by the double feed detecting means, the first mode in which the sheet in which the double feed is detected is discharged to the double feed sheet discharging unit via the escape transport path and the double feed are detected. without discharging the sheet to the double feed sheet discharge unit, and control means capable of executing a second mode for stopping, to the sheet conveying path, the control means, the sheet double feed is detected executing said second mode when a predetermined type including a thin paper, executing the first mode when double feed is sheet sensed not the predetermined type, the sheet conveying device, characterized in that Is.

According to the present invention, in addition to discharging the sheet to the double feed sheet discharging section when the double feed is detected, the sheet in which the double feed is detected is not discharged to the double feed sheet discharge section, but is placed on the sheet transport path. It can be stopped. For this reason, when double feeding occurs, it is possible to discharge the sheet in which the double feeding is detected to the double feeding sheet discharging section so that downtime does not occur as much as possible, and there is a possibility other than downtime. In consideration, the seat can be stopped on the seat transport path at a predetermined timing.

The whole schematic which shows the printer which concerns on embodiment of this invention. The block diagram which shows the control device of the printer of FIG. Flow chart diagram of double feed processing. The schematic diagram which shows the length of the threshold value in a double feed process. (A) is a diagram showing a state in which the transfer of the double feed sheet is stopped by the second mode, and (b) is a diagram showing a state in which the resist adjusting device is opened for jam processing. (A) A diagram showing a state in which seat jam has occurred in the escape transport path, and (b) a diagram showing a state in which the escape transport path is open. The schematic diagram which shows the length of another threshold value in a double feed process. (A) is a diagram showing another example in which the stop timing of the double feed sheet in the second mode is changed, and (b) is a diagram showing a long feeder configured so that the sheet transport path can be opened. (A) is a schematic diagram illustrating a state in which a long sheet causes a sheet jam in an escape transport path, and (b) is a schematic diagram showing a state in which the escape transport path is open.

Hereinafter, the sheet transport device according to the embodiment of the present invention will be described. The printer 1 will be described as an example of the sheet transport device in the following description, but the printer 1 includes an apparatus main body 100, a paper deck 101, a resist adjusting device 103, and a long feeder 102, which will be described later. Functions as a sheet transfer device. Further, the sheet transfer device can be configured only by the parts of the paper deck 101, the resist adjusting device 103, and the long feeder 102 excluding the device main body 100 that forms an image. Further, an escape tray may be provided in the main body of the device, and the sheet transport device may be configured by the transport portion in the main body of the device.

<Overall configuration of printer>
First, the overall configuration of the printer 1 in the present embodiment will be described with reference to FIG. As shown in FIG. 1, the printer 1 which is an image forming apparatus includes an apparatus main body 100 for forming an image on a sheet, a paper deck 101 for feeding the sheet to the apparatus main body 100, and a long feeder 102. It is configured. The paper deck 101 is a large-capacity stacker that is connected to the apparatus main body 100 and can load a larger amount of sheets than the sheet cassettes 61 to 64 in the apparatus main body 100. Further, the long feeder 102 is connected to the paper deck 101 via a resist adjusting device 103, and is configured to be capable of loading a long sheet having a predetermined length or more.

The apparatus main body 100 is provided with an image reading unit 21 having a scanning optical system for reading an image at the upper part thereof, and an image forming unit 22 for forming an image on a sheet below the image reading unit 21. Further, below the image forming unit 22, a plurality of front loading type sheet cassettes 61 to 64 are provided, which accommodate the sheets and are mounted so as to be able to be taken in and out from the front side of the apparatus.

The image forming unit 22 includes image forming stations 23Y to 23K for forming images for each color of yellow Y, magenta M, cyan C, and black K, and the image forming stations 23Y to 23K are along the intermediate transfer belt 31. It is a tandem type image forming part arranged side by side. The yellow image forming station 23Y includes a photosensitive drum 11Y, a charging device 12Y, an exposure device 13Y, a developing device 14Y, a primary transfer roller 35Y, a cleaning blade 15Y, and the like around the photosensitive drum 11Y.

The charging device 12Y charges the surface of the photosensitive drum 11Y to a predetermined potential, and the exposure device 13Y forms an electrostatic latent image on the surface of the photosensitive drum 11Y uniformly charged by the charging device 12Y. Further, the developing device 14Y develops an electrostatic latent image formed on the photosensitive drum 11Y with toner to form a toner image. The primary transfer roller 35Y forms a primary transfer nip between the photosensitive drum 11Y and the intermediate transfer belt 31, and by applying a transfer bias, the toner image on the photosensitive drum 11Y is transferred onto the intermediate transfer belt 31. It is configured as follows. Further, the cleaning blade 15Y is configured to come into contact with the surface of the photosensitive drum 11 on the downstream side of the primary transfer nip to remove residual toner remaining on the photosensitive drum 11Y after the primary transfer. Since the other image forming stations 23M to 23K have basically the same configuration as the yellow image forming station 23Y described above except for the toner color used, the description thereof will be omitted.

The intermediate transfer belt 31 transfers the image formed on the intermediate transfer belt 31 together with the secondary transfer inner roller 32 and the secondary transfer outer roller 41 to the sheet on the downstream side of the black image forming station 23K. The transfer portion T2 is formed. Further, a fixing device 5 is provided downstream of the secondary transfer unit T2 in the sheet transport direction, and the fixing device 5 pressurizes and heats the unfixed image on the sheet to be fixed to the sheet.

Since the printer 1 is configured in this way, for example, when printing an image read by the image reading unit 21, the read image information is photoelectrically converted, and images for each color are obtained by the image forming stations 23Y to 23K. To form. Then, the image formed by the image forming stations 23Y to 23K is primaryly transferred so as to be superimposed on the intermediate belt, and this image is transferred to the secondary transfer unit T2 by the sheet cassette 61 to 64, the paper deck 101 or the long feeder. Secondary transfer is performed on the sheet supplied from 102.

After that, heat and pressure are applied to the sheet on which the image is transferred by the secondary transfer unit T2 to fuse the toner image, and if the single-sided image forming mode is specified by the user, the discharge port 50 It is discharged to the outside of the device. Further, in the double-sided image forming mode, the image is sent to the inversion pass 52, and is sent to the image forming unit 22 again through the double-sided pass 85.

<Paper deck configuration>
The configuration of the paper deck 101 will be described in detail. As shown in FIG. 1, the paper deck 101 is used as a transporting means corresponding to the sheet loading portions 110a to 110c having a larger capacity than the sheet cassettes 61 to 64 provided in the apparatus main body 100 and the sheet loading portions 110a to 110c. The paper feed units 120a to 120c are provided. The paper feeding units 120a to 120c are suction transporting means for sucking and transporting the sheets on the sheet loading sections 110a to 110c by electrostatic force, and the feeding means for feeding the sheets loaded on the sheet loading sections 110a to 110c. Consists of.

Further, the paper deck 101 branches from the sheet transport path R1 for guiding the sheets fed from the sheet loading portions 110a to 110c to the apparatus main body 100 and the sheet transport path R1 and guides the sheets to the escape tray 232. It is provided with an escape transport path R2. A plurality of transport roller pairs 205 to 218 are arranged on the sheet transport path R1 so as to deliver the fed sheet to the apparatus main body 100. In the present embodiment, the sheet transport path is fed from the sheet loading portions 61 to 64, 110a to 110c, and 130, and after the image is formed, until it is discharged to the outside of the apparatus (this). In the embodiment, it means a discharge route through which the sheet passes through the discharge port (from the discharge port 50 to discharge). The sheet transport path R1 constitutes the sheet transport path in the paper deck 101.

On the other hand, the escape transfer path (escape transfer path) R2 branches upward from the sheet transfer path R1 at the branch portion 231 on the downstream side of the transfer roller pair 217, and the transfer roller is on the escape transfer path R2. Pairs 219 to 222 are arranged. The sheets conveyed by the transfer roller pairs 219 to 221 are discharged to the escape tray 232 provided on the upper surface of the paper deck 101 by the escape discharge roller pair 222 provided at the end of the escape transfer path R2.

Further, a receiving roller pair 223 and 224 are provided on the right side of the paper deck 101 so that the sheet can be delivered to the paper deck 101 from the resist adjusting device 103 provided on the right side of the paper deck 101. Further, a double feed detector 233 as a double feed detecting means for detecting double feed of the seat is provided downstream of the transport roller pair 213 and upstream of the transport roller pair 214 on the seat transport path R1. The escape tray 232 is a double feed sheet discharge section in which the sheet for which double feed is detected is discharged via the escape transport path branched from the middle part of the sheet transport path, and is double feed by the double feed detector 233. The sheet in which is detected is discharged to the escape tray 232.

In the present embodiment, the double feed detector 233 is composed of an ultrasonic wave transmitting sensor and an ultrasonic wave receiving sensor, and is based on the degree of attenuation of ultrasonic waves passing through the sheets when the sheets are overlapped. It is judged that it is a double delivery. Further, the double feed detection method does not necessarily have to use an ultrasonic sensor, and may be configured by, for example, an optical sensor, and is heavy based on the fed sheet length, not the thickness. Sending may be detected. Further, the double feed detector 234 described later also has the same configuration as the double feed detector 233 described above.

<Structure of long feeder and resist adjusting device>
The long feeder 102 corresponds to the long sheet loading section 130 and the long sheet loading section 130 that can load long sheets that cannot be accommodated in the apparatus main body 100 and the paper deck 101 in the sheet transport direction. It is provided with a paper feed unit 140. The paper feed unit 140 is a suction transport means for sucking and transporting the sheets on the long sheet loading section 130 by electrostatic force, and feeds the sheets loaded on the long sheet loading section 130 as the sheet loading section. It constitutes a sheet feeding means.

Further, the long feeder 102 includes transport rollers pairs 225 and 226 for transporting the sheets fed by the paper feed unit 140, and the resist adjusting device transports the long sheets by these transport roller pairs 225 and 226. Hand over to 103. Further, a double feed detector 234 for detecting the double feed of the sheet is provided between the transport rollers 225 and 226, and the long feeder 102 is a sheet length detecting means for detecting the length of the sheet. The seat length detector 235 (see FIG. 2) is provided. The sheet length detector 235 is provided in the long sheet loading unit 130, and has a sensor that detects the size of the loaded sheet with, for example, a flag and a photo sensor, a photo sensor that detects the sheet on the sheet transport path, and the like. Consists of. By using these sensors, it is possible to detect the length of the sheet in the transport direction based on the detected sheet size, the passing time from the front end to the rear end of the sheet on the sheet transport path, and the like. Further, the sheet length detector 235 detects the position of the rear end restricting plate or the like that regulates the rear end position of the sheet on the long sheet loading unit 130, and directly detects the length in the sheet transport direction. You may do so.

Further, the resist adjusting device 103 includes transfer roller pairs 227 to 230, and while the sheet is conveyed by these transfer roller pairs 227 to 230, the sheet is skewed and laterally registered by a resist adjusting means (not shown). It is configured to adjust the deviation. The sheet corrected for skewing and lateral displacement is delivered to the paper deck 101 from the transport roller pair 230 provided at the most downstream in the sheet transport direction. Further, the resist adjusting device 103 is provided with a transport sensor (seat detecting means) 236 between adjacent transport roller pairs 230 and 229, and the transport sensor 236 can detect the presence or absence of a sheet. It has become.

<Control device configuration>
Next, the configuration of the control device 300 as the control means of the printer 1 will be described. As shown in FIG. 2, the control device 300 includes a CPU 300a as a calculation means for executing various calculations, and a ROM 300b and a RAM 300c constituting the storage means. The RAM 300c functions as a working area of the CPU 300a, and the ROM 300b stores various programs used for controlling the printer 1.

Further, various sensors such as a double feed detector 234, a sheet length detector 235, and a transport sensor 236 as double feed detection means are connected to the control device 300. Further, the drive motors 237a to 237c of the transfer roller pair 225 to 230, the transfer switch 239, and the like are connected. The first drive motor 237a drives the transfer rollers 225 and 226, the second drive motor 237b drives the transfer rollers 227 and 228, and the third drive motor 237c drives the transfer rollers 229 and 230. There is. Further, the transport switching device 239 as the switching means is provided so as to be movable between the first and second positions at the branch portion 231 and has a switching member (not shown) and a solenoid that changes the posture of the switching member. .. By locating the switching member at the first position, the seat is guided to the seat transport path R1, and by locating at the second position, the seat is guided to the escape transport path R2. Further, the control device 300 is connected to an operation panel 240 on which a user performs an input operation to the printer 1 and displays various information.

Here, the double feed processing program P1 executed when the double feed detectors 233 and 234 detect the double feed is stored in the ROM 300b. In the present embodiment, the double feed detector 233 detects the double feed of the sheets fed from the sheet loading portions 110a to 110c of the paper deck 101, and the double feed detector 234 is the long sheet of the long feeder 102. The double feed of the sheet fed from the loading unit 130 is detected. When the double feed detector 233 detects the double feed, the double feed processing program P1 sets the sheet in which the double feed is detected to the escape transport path R2 in order to minimize the downtime due to the processing of the double feed sheet. It is retracted to the escape tray 232 via the escape tray 232.

On the other hand, if the double feed detector 234 that detects the double feed of the sheet fed from the long sheet loading unit 130 detects the double feed, the sheet is always retracted to the escape tray 232. There are the following possibilities. That is, for example, as shown in FIG. 9A, when a long sheet causes a sheet jam in the escape transfer path R2, a part of the sheet still remains on the sheet transfer path R1 and a large number of transfer roller pairs. It may be sandwiched between.

In this case, as shown in FIG. 9B, the sheet transport path R1 and the escape transport path R2 are opened to urge the user to remove the sheet that has caused the seat jam, but the user mistakenly urges the user to remove the sheet, but the user mistakenly shows FIG. 9 (a). There is a risk of pulling the sheet in the state of). Then, since the sheet is pulled out in a state where a large number of transfer roller pairs are pressurized in the escape transfer path R2 and the sheet transfer path R1, the sheet is torn depending on the pulling method, and the sheet piece becomes the sheet transfer path. There is a risk that it will remain in R1.

In particular, when there are a large number of double-fed sheets, the rigidity and bulge of the sheets are large, and the transfer resistance when passing through the escape transfer path R2 formed by bending becomes excessive, so that the inside of the escape transfer path It is easy to cause escape jam, which is a seat jam in.

Therefore, the double feed processing program P1 is configured to selectively execute the first and second modes when the double feed detector 234 detects the double feed. That is, the double feed processing program P1 can eject the double feed sheet to the escape tray 232 based on the sheet length detection result detected by the sheet length detector 235 as the first mode. .. Further, as the second mode, the double feed sheet can be stopped at a predetermined position without being retracted to the escape tray 232. More specifically, when the length of the sheet in which double feed is detected in the sheet transport direction is shorter than the predetermined length, the first mode is executed, and the length of the sheet in which double feed is detected in the sheet transport direction is It is configured to execute the second mode when the length is longer than a predetermined length. Hereinafter, these first and second modes will be described in detail.

<Explanation of double feed processing>
Based on FIGS. 3 to 6, the double feeding process when the double feeding of the sheets fed from the long feeder 102 is detected will be described in detail. As shown in FIG. 3, when the double feed detector 234 detects the double feed after the start of the feed, the control device 300 determines that the double feed is detected based on the detection result of the sheet length detector 235. It is determined whether or not the length is equal to or longer than the predetermined length (S1 in FIG. 3). More specifically, in the present embodiment, the predetermined length is the sheet length D1 extending from the transport roller pair 217 to the escape discharge roller pair 222, that is, the length of the escape transport path R2, as shown in FIG. It is set to.

Then, when the control device 300 determines that the length of the sheet that has detected the double feed is shorter than the length D1 (No of S1), the control device 300 decides to execute the first mode and is arranged in the branch portion 231. The switching member of the switching device 239 is switched from the first position to the second position (S2). When the switching member is switched to the second position, the sheet for which double feeding is detected is guided to the escape transport path R2 and discharged to the escape tray 232. When the ejection of the sheet to the escape tray 232 is completed, the switching member is controlled to return to the first position.

On the other hand, when the control device 300 determines that the length of the sheet that has detected the double feed is the length D1 or more (Yes in S1), the control device 300 does not retract the double feed sheet to the escape tray 232 and stops the double feed sheet at a predetermined position. Decide to run the mode. When the control device 300 determines to execute the second mode, the control device 300 detects the tip of the double feed sheet by the transfer sensor 236 of the resist adjusting device 103 (S3), and the first to third drive motors 237a to Stop 237c (S4). At the same time, a warning prompting jam processing is displayed on the operation panel 240 (see FIG. 2) (S5).

When the first to third drive motors 237a to 237c are stopped at the timing when the transfer sensor 236 detects the double feed sheet, the double feed sheet is on the sheet transfer path in the resist adjusting device 103 as shown in FIG. 5 (a). Stop at. When the sheet is stopped in the resist adjusting device, the user opens the cover of the resist adjusting device 103 with reference to the jam processing procedure displayed on the operation panel 240, and transports the sheet as shown in FIG. 5 (b). Separate the rollers 227-230. Then, the user removes the double feed sheet stopped on the sheet transport path.

Since the printer 1 according to the present embodiment is configured in this way, when double feeding of a long sheet having a predetermined length or longer is detected, the sheet is conveyed in consideration of the possibility of sheet jam on the escape transfer path. The seat can be stopped at a predetermined position on the road. More specifically, since the sheet is stopped in the resist adjusting device 103 forming the linear sheet transport path, the user can easily open the cover of the resist adjusting device 103 to easily feed the double feed sheet. Can be removed. Further, since the sheet is not forcibly pulled, a sheet piece or the like is not left behind in the sheet transport path due to a part of the sheet being torn.

Further, when the length of the sheet for which double feeding is detected is shorter than the predetermined length, the double feeding sheet is discharged to the escape tray 232 via the escape transport path R2. Therefore, it is not necessary to stop the operation of the printer 1 every time the double feed is detected, and the downtime caused by the double feed can be reduced.

Further, even if a sheet jam occurs in the escape transfer path R2 as shown in FIG. 6A, the length of the jammed sheet is shorter than the length of the escape transfer path R2. Therefore, the sheet S1 protruding from the escape discharge roller pair 222 is not pinched by the transport roller pair on the sheet transport path R1, or even if it is pinched, it is only slightly pinched. Therefore, as shown in FIG. 6B, even if the user pulls the sheet S1 in the state of FIG. 6A without opening the escape transfer path R2, the sheet is torn and the inside of the sheet transfer path R1. It is possible to prevent the sheet piece from remaining on the surface.

In the above-described embodiment, only one predetermined length, which is a threshold value for determining whether to execute the first mode or the second mode, is provided, but the present invention is limited to this. However, a plurality of threshold values may be set. That is, for example, in the case of a sheet such as thin paper that is easily torn, the predetermined length may be changed to a length shorter than the length D1 depending on the type of the sheet. More specifically, for example, as shown in FIG. 7, the predetermined length may be set to the sheet length D2 extending from the transport roller pair 219 to the escape discharge roller pair 222 according to the type of the sheet.

Further, when a threshold value for the length is not set and double feeding occurs in a predetermined type of sheet such as the thin paper, the second mode is executed without executing the first mode. Is also good. The control device 300 may determine the type of the sheet in which the double feed has occurred based on the sheet information such as the type and size of the sheet input in advance corresponding to the sheet loading unit, or the type of the sheet. A sheet type sensor as a sheet type detecting means for detecting the above may be separately provided. Further, the control device 300 may also determine the length of the sheet in which the double feed has occurred, based on the sheet information, without providing the sheet length detector 235.

Further, in the above-described embodiment, in the second mode, the transfer of the double feed sheet is stopped based on the sheet detection timing when the transfer sensor 236 detects the sheet, but the present invention is not limited to this. For example, as shown in FIG. 8A, the double feed detector 234 may be configured to stop the transport of the double feed sheet based on the double feed detection timing when the double feed is detected. Further, the timing of stopping the transfer of the sheet does not have to be stopped immediately after the transfer sensor 236 detects the sheet or the double feed detector 234 detects the double feed, and the transfer sensor, the double feed detector, etc. It may be after a predetermined time has elapsed after the detection of the predetermined sensor. That is, in the second mode, the transport of the seat may be stopped at a predetermined timing according to a desired position to be stopped.

Further, when the sheet transfer is stopped immediately after the double feed detector 234 detects the double feed as shown in FIG. 8 (a), the upper surface of the long feeder 102 opens as shown in FIG. 8 (b). It is desirable to do so. If such a configuration is adopted, jam processing on the long feeder 102 side can be easily performed.

Further, the sheet transfer device may be provided with a sheet processing device that performs processing such as staples and bookbinding on the sheet after forming an image. For example, the sheet processing device is provided with an escape transfer path, an escape tray, and the like. Is also good. Further, in the above-described embodiment, the control device 300 is provided in the device main body 100, but the present invention is not limited to this. For example, the control device may be provided on the paper deck 101, the long feeder 102, the sheet processing device, or the like, or a plurality of CPUs, ROMs, RAMs, etc. may be provided on the main body of these devices or other units, and these may be cooperated with each other. The control device may be configured by the above. Further, the inventions described in the above-described embodiments may be combined in any way.

1: Printer (sheet transfer device) / 22: Image forming unit / 130: Sheet loading unit / 140: Paper feed unit (sheet feeding means) / 232: Escape tray (double feed sheet discharge section) / 234: Double feed detection Device (double feed detection means) / 236: Conveyance sensor (sheet detection means) / 300: Control device (control means)

Claims (7)

The seat loading section for loading seats and
A sheet feeding means for feeding the sheet loaded on the sheet loading section, and a sheet feeding means.
A double feed detecting means for detecting double feed of a sheet fed from the sheet feeding means, and a double feed detecting means.
A double feed sheet discharge section in which the sheet for which double feed is detected by the double feed detection means is discharged via an escape transport path branched from the middle portion of the sheet transport path.
When the double feed is detected by the double feed detecting means, the first mode in which the sheet in which the double feed is detected is discharged to the double feed sheet discharging unit via the escape transport path and the double feed are detected. A second mode for stopping the sheet on the sheet transport path without discharging the sheet to the double feed sheet discharging unit, and a control means capable of executing the second mode are provided.
The control means executes the first mode when the length of the sheet in which the double feed is detected in the sheet transport direction is shorter than a predetermined length corresponding to the length of the escape transport path, and the double feed is detected. The second mode is executed when the length of the sheet in the sheet transport direction is equal to or greater than the predetermined length.
A sheet transfer device characterized by this. The seat loading section for loading seats and
A sheet feeding means for feeding the sheet loaded on the sheet loading section, and a sheet feeding means.
A double feed detecting means for detecting double feed of a sheet fed from the sheet feeding means, and a double feed detecting means.
A double feed sheet discharge section in which the sheet for which double feed is detected by the double feed detection means is discharged via an escape transport path branched from the middle portion of the sheet transport path.
When the double feed is detected by the double feed detecting means, the first mode in which the sheet in which the double feed is detected is discharged to the double feed sheet discharging unit via the escape transport path and the double feed are detected. A second mode for stopping the sheet on the sheet transport path without discharging the sheet to the double feed sheet discharging unit, and a control means capable of executing the second mode are provided.
Wherein, the sheet double feed is detected by executing the second mode when a predetermined type including a thin paper, double feeding the first if there is sheet sensed not the predetermined type Run the mode,
A sheet transfer device characterized by this. A sheet detecting means for detecting a sheet on the sheet transport path downstream of the double feed detecting means in the sheet transport direction is provided.
In the second mode, the control means stops the transfer of the sheet based on the sheet detection timing of the sheet detection means.
The sheet transport device according to claim 1 or 2, wherein the sheet transport device is characterized by the above. In the second mode, the control means stops the sheet transfer based on the double feed detection timing of the double feed detection means.
The sheet transport device according to claim 1 or 2, wherein the sheet transport device is characterized by the above. In the second mode, the control means stops the sheet downstream of the double feed detecting means in the sheet transport direction.
The sheet transport device according to any one of claims 1 to 4, wherein the sheet transport device is characterized by the above. The control means changes the predetermined length depending on whether or not the sheet in which the double feed is detected is of a predetermined type including thin paper.
The sheet transport device according to claim 1, wherein the sheet transport device is characterized by the above. An image forming unit for forming an image on a sheet fed from the sheet feeding means is provided.
The sheet transport device according to any one of claims 1 to 6, wherein the sheet transport device is characterized.

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