JPH10279158A - Post-processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent clogging of paper of postcard size in a paper discharge port by providing a paper discharge tray position control means which increases an amount of descent of a paper discharge tray up to an amount which is larger than a predetermined amount when postcard size is recognized and a position of the paper discharge tray of a picture image formation device after paper is discharged is too high. SOLUTION: A main control plate 31 returns to the check of an output signal of a paper surface detection sensor S3 when a timer does not reach a set value and rotates a motor by, for example, 10 to 15 ms to lower a paper discharge tray by an amount which corresponds to a thickness of paper having postcard size when it recognizes that a size of paper discharged from a picture image formation device 1 is the postcard size based on the information related to the paper from the picture image formation device 1 when the timer reaches the set value. Next, the motor M4 is stopped to stop the paper discharge tray, and the timer is reset to zero to return to the check of an output signal of the paper surface detection sensor S3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a post-processing apparatus connected to an image forming apparatus such as a copying machine and a printer.

[0002]

2. Description of the Related Art A post-processing apparatus connected to an image forming apparatus such as a copying machine or a printer receives sheets discharged from the image forming apparatus and loads a large number of sheets on a discharge tray. In this post-processing device, in order to improve the stackability of the sheets, the height of the sheets discharged onto the sheet discharge tray is detected, and whether the height of the sheet discharge tray is too high compared to the sheet discharge port is determined. If the height of the paper output tray is determined to be too high compared to the paper output port, the paper output tray and the paper output tray are always at the same position by lowering the paper output tray little by little. The height of the discharge tray is controlled as described above.

Japanese Patent Application Laid-Open No. 5-305786 discloses a mode in which sheets ejected from an image forming apparatus are continuously stacked on a sheet ejection tray, and a sheet ejected from an image forming apparatus is stapled inside. A discharge tray control device that changes the lowering control of the discharge tray in a mode of stacking on the discharge tray later is described.

[0004] Specifically, this paper discharge tray control device includes:
In a discharge tray control device attached to an image forming apparatus and configured to control a plurality of discharge trays that store sheets discharged from the image forming apparatus in a predetermined tray according to a preset mode according to the mode, The tray can be moved up and down, one sheet tray is ejected one sheet at a time in the sorting mode, one sheet tray is ejected in the staple mode, and the second sheet tray is ejected in the staple mode. And a control means for gradually lowering the discharge tray from a second home position slightly higher than the first home position in the sorting mode. It is a tray control device.

[0005]

In the above-mentioned post-processing apparatus,
Detects the height of the paper ejected on the output tray and determines whether the height of the output tray is too high compared to the output port. If it is determined that the height is too high, the height of the paper output tray is controlled so that the paper output port and the paper output tray are always at the same position by lowering the paper output tray little by little. If the device ejects paper of a postcard size, envelope size, etc. that is thicker than normal paper, the amount to lower the output tray is insufficient, and the paper is jammed in the output port or the paper falls from the output tray. There was a problem that

According to the present invention, when a sheet of a postcard size, an envelope size, or the like thicker than a normal sheet is ejected from the image forming apparatus, the sheet is jammed in the sheet ejection outlet or the sheet falls from the sheet ejection tray. It is an object of the present invention to provide a post-processing device that can solve the problem.

[0007]

According to a first aspect of the present invention, there is provided a post-processing apparatus for receiving sheets discharged from an image forming apparatus and stacking the sheets on a discharge tray. Paper size recognizing means for recognizing the size of the paper when receiving the paper discharged from the forming apparatus; and, based on an output signal of the paper size recognizing means, the position of the discharge tray after discharging the paper of the image forming apparatus is high. Paper tray position control means for lowering the paper discharge tray by a predetermined amount when the paper size has passed, the paper discharge tray position control means of the image forming apparatus when the paper size recognition means recognizes a postcard size as a paper size. When the position of the discharge tray after discharging the paper is too high, the amount by which the discharge tray is lowered is made larger than the predetermined amount. Can sheet from the sheet discharge tray or a paper jam in the discharge port when the normal paper thicker postcard size than the paper is discharged to eliminate the inconvenience that or fall from.

According to a second aspect of the present invention, in the post-processing apparatus according to the first aspect, when the sheet size recognizing unit recognizes the envelope size as the sheet size, the sheet discharge tray position control unit may control the sheet size of the image forming apparatus. When the position of the discharge tray after discharging is too high, the amount by which the discharge tray is lowered is made larger than when the paper size recognition unit recognizes a postcard size as a paper size. It is possible to solve the problem that when a sheet having an envelope size thicker than a normal sheet is ejected, the sheet is jammed in the sheet ejection outlet or the sheet falls from the sheet ejection tray.

According to a third aspect of the present invention, there is provided a post-processing apparatus for receiving sheets discharged from an image forming apparatus and stacking the sheets on a discharge tray, wherein the sheet discharged from the image forming apparatus is received when the sheets are received. Paper size recognizing means for recognizing the size of a sheet, and when the paper size recognizing means recognizes a postcard size as a paper size, a fixed amount is set every time paper is discharged from the image forming apparatus regardless of the position of the discharge tray. A discharge tray position control means for lowering the discharge tray, the image forming apparatus not only when the image processing capacity of the image forming apparatus is low but also when the image processing capacity of the image forming apparatus is high. Resolves the problem that paper is jammed in the paper exit and drops from the paper output tray when paper with a postcard size thicker than normal paper is ejected from Rukoto can.

According to a fourth aspect of the present invention, in the post-processing apparatus according to the third aspect, when the sheet size recognizing unit recognizes the envelope size as the sheet size, the sheet discharging tray position control unit transmits the sheet from the image forming apparatus. Every time is discharged, the amount by which the discharge tray is lowered each time is larger than when the paper size recognition unit recognizes the postcard size as the paper size, and only when the processing capability of the image forming apparatus is low. Even when the image forming apparatus has a high processing capacity, if the image forming apparatus ejects a sheet having an envelope size that is thicker than a normal sheet, the sheet may become jammed in the discharge port or the sheet may drop from the discharge tray. Can be solved.

[0011]

FIG. 2 schematically shows an embodiment of the invention, FIGS. 3 and 4 show a stipple unit of the embodiment, and FIG. 5 is an enlarged view of a part of the embodiment. Show. This embodiment is an embodiment of the first and second aspects of the present invention. The post-processing apparatus of this embodiment is, as shown in FIG.
For example, the transfer paper O connected to the paper output unit of the image forming apparatus 1 composed of a copying machine and discharged from the paper output unit of the image forming apparatus 1
A first transport path A for sorting / stacking which transports a sheet such as an HP sheet directly to the discharge tray 3 by the switching claw 2, a second transport path B for performing staple (binding) or inversion of the sheet, and the second transport A third transport path C is provided for transporting the sheet entering the path B to the first transport path A again by the reverse rotation of the transport roller 8. In addition, the switching claw 2 rotates around the rotation center 2a.

The paper discharge tray 3 is disposed downstream of the first transport path A in the paper transport direction, and has a function of stacking non-stapled paper and stapled paper. In the vicinity of the entrance of the post-processing device, there are provided a transport roller 4 for receiving the sheet discharged from the image forming apparatus 1 and a driven roller 5 driven by the transport roller. An entrance sensor is provided immediately before the transport roller 4 and the driven roller 5. S1 is provided. The entrance sensor S1 detects a sheet discharged from the image forming apparatus 1 and conveyed.

The switching claw 2 is disposed on the downstream side of the transport roller 4 in the paper transport direction, and is normally located at a dashed line position in FIG. 2 by a spring to switch the paper transport direction to the first transport path A side, but is not shown. When driven by the solenoid and turned to the solid line position in the figure, the paper transport direction is switched to the second transport path B side. A transport roller 6 and a driven roller 7 driven by the transport roller 6 are disposed in the first transport path A, and the transport roller 6 and the driven roller 7 transport the sheet to the discharge tray 3.

A transport roller 8 and a driven roller 9 driven by the transport roller 8 are disposed in the second transport path B. The transport roller 8 and the driven roller 9 transport the sheet from the switching claw 2 to the staple unit D. Further, the sheet is transported to the third transport path C at the time of reversing. As shown in FIGS. 3 and 4, the stapling unit D is a stapler 1 for stapling a sheet.
0, a jogger fence 11 for aligning the paper in a direction orthogonal to the transport direction, a paper discharge belt 12 for discharging the paper stapled by the stapler 10 to the paper discharge tray 3, and a paper discharge belt 12 , A staple tray 20, a reference fence 21, and the like.

The sensor S2 detects the paper ejection claw 13, and the main control plate 31 (see FIG. 1) as a control means is provided with the sensor S2.
The output belt drive motor M6 (see FIG. 1) is controlled based on the output signal so that the trailing end position of the sheet is constant even if the sheet size is different. As shown in FIG. 3, the paper reference at the time of paper staple is arranged outside the paper having the maximum width when the paper is inverted. The paper discharge claw 13 has a function as a fence for aligning the edges of the paper on the staple tray 20 and a function to send out the stapled paper bundle to the paper discharge tray 3.

FIG. 5 is an enlarged view of a sheet discharge section of the post-processing apparatus. In this post-processing apparatus, a paper discharge roller 14 and a driven roller 17 driven by the paper discharge roller 14 are arranged at a paper discharge port for discharging the paper to the paper discharge tray 3, and the paper discharge roller 14 and the driven roller 17 do not staple. Also, the stapled paper and the inverted paper are discharged to the paper discharge tray 3. The driven roller 17 is normally located at a position in contact with the paper discharge roller 14, but can be moved together with the paper discharge guide plate 18 around the fulcrum a to the position shown by a dashed line in FIG. ing. The driven roller 17 comes into contact with the paper discharge roller 14 under its own weight while being pressed.

The discharge tray 3 can be moved up and down along a guide plate 22 by a vertical guide roller 15, and a motor M4 (see FIG. 1) as a drive source for driving the discharge tray up and down. Driven by The paper discharge tray 3 can be moved by a shift guide roller 16 in a direction orthogonal to the paper discharge direction, and is driven by a motor M3 (see FIG. 1) as a paper discharge tray shift drive source.

The paper surface detecting sensor S3 is a sensor as a paper height detecting means for detecting the upper surface of the paper discharged to the paper discharge tray 3 (the height of the paper on the paper discharge tray 3). Controls the motor M4 based on the output signal of the sheet surface detection sensor S3 to adjust the height of the sheet discharge tray 3 so that the upper surface of the sheets discharged and stacked on the sheet discharge tray 3 always keeps the upper side of the sheet discharge port. Control so as to be at a fixed position. The paper discharge sensor S5 detects the paper discharged to the paper discharge tray 3 before the paper discharge roller 14 and the driven roller 17. In FIG. 2, reference numeral 23 denotes a reversal guide member for guiding a sheet,
Reference numeral 4 denotes a reversing entrance sensor that detects a sheet at a reversing entrance near the entrance of the second conveyance path B (immediately after the switching claw 2).

FIG. 1 shows a circuit configuration of the post-processing apparatus.
The 24 V power line of the image forming apparatus 1 is connected to the main control board 3.
1 is connected to one end of each of the motors M1 to M7 and the solenoid SOL1 via the switch SW in series, and the 5V power supply line of the image forming apparatus 1 connects the fuse 32 and the switch SW in the main control plate 31 in series. Are connected to one end of each of the sensors S1 to S5.

The main control plate 31 controls the motors M1 to M7, the solenoid SOL1, and the other end of each of the sensors S1 to S5 to control them, and takes in output signals of the sensors S1 to S5. The motor M1 rotates the transport roller 4, and the motor M2 rotates the transport rollers 6, 8 and the discharge roller 14. The motor M5 moves the jogger fence 11, and the motor M6 rotates the discharge belt 12. The motor M7 drives the stapler 10 and the solenoid SOL1
Drives the switching claw 2.

The operation of the post-processing apparatus includes a sorter stack mode in which the sheets are discharged directly to the discharge tray 3 one by one without performing the stapling of the sheets, and a sorter stack mode in which the sheets are stapled and discharged to the discharge tray 3. There are a staple mode for discharging paper and a reversal mode for discharging paper to the paper discharge tray 3 after reversing the paper.

First, in the sorter / stack mode, the switching claw 2 is at the position indicated by the dashed line in the figure, and the paper discharged from the image forming apparatus 1 is transported by the rollers 4, 6, the paper discharge roller 14, and the driven rollers 5, 7, The paper is conveyed through the first conveyance path A by 17 and discharged to the paper discharge tray 3 from the paper discharge port. The sheets discharged from the image forming apparatus 1 are successively discharged to the discharge tray 3 and stacked, and the sheet surface detection sensor S3 detects the upper surface of the sheets discharged and stacked on the discharge tray 3.

The main control plate 31 controls the motor M4 based on the output signal of the paper surface detection sensor S3 to control the output tray 3
Is controlled such that the upper surface of the sheets discharged and stacked on the discharge tray 3 is always at a fixed position with respect to the discharge port. The main control plate 31 sorts the sheets by controlling the motor M3 as necessary to shift the sheet discharge tray 3 in a direction (sheet width direction) orthogonal to the sheet conveyance direction.

In the staple mode, the switching claw 2 is driven by the solenoid SOL1 to rotate to the position indicated by the solid line. The sheet discharged from the image forming apparatus 1 is transported by the transport roller 4 and the driven roller 5, sent to the second transport path B by the switching claw 2, and sent to the staple unit D by the transport roller 8 and the driven roller 9. Conveyed. The main control plate 31 controls the motor M6 based on the output signal of the paper surface detection sensor S2 so that the rear end of the paper is at a fixed position with respect to the transport roller 8, and moves the position of the paper discharge claw 13 to the staple tray. 20 on the paper transport path.

A push roller 8 'larger than the diameter of the transport roller 8 is provided on the same axis as the transport roller 8. The leading end of the paper strikes the paper ejecting claw 13 and at the same time, the rear end pushes the paper toward the staple tray 20. Can be Next, the paper is moved toward the reference fence 21 by the jogger fence 11 in a direction orthogonal to the transport direction, and is stacked on the staple tray 20 in a state where the paper abuts on the reference fence 21 and the paper discharge claw 13.

Such an operation is repeated each time the sheet discharged from the image forming apparatus 1 enters the staple tray 20, and the staple tray 20 is stacked with the sheets aligned. Next, a predetermined number of sheets stacked on the staple tray 20 are stapled by the stapler 10. The stapled sheet bundle is conveyed by a discharge belt 12 and a discharge claw 13, conveyed by a discharge roller 14 and a driven roller 17, and discharged to a discharge tray 3 from a discharge port.

The bundle of sheets discharged to the sheet discharge tray 3 abuts against the guide plate 22 by its own weight, and is stacked on the sheet discharge tray 3 with its rear end aligned. The paper surface detection sensor S3 detects the upper surface of a stack of sheets discharged and stacked on the discharge tray 3. The main control plate 31 controls the motor M4 based on the output signal of the sheet surface detection sensor S3 to adjust the height of the sheet discharge tray 3 so that the upper surface of the stack of sheets discharged and stacked on the sheet discharge tray 3 always has the above-mentioned discharge. Control is performed so as to be at a fixed position with respect to the paper exit. The main control plate 31 sorts the sheet bundle by controlling the motor M3 as necessary to shift the sheet discharge tray 3 in a direction (sheet width direction) orthogonal to the sheet conveyance direction.

In the reversing mode, the switching claw 2 is set to the solenoid S
It is driven by OL1 to rotate to the position indicated by the solid line. The sheet discharged from the image forming apparatus 1 is conveyed by the conveying roller 4 and the driven roller 5 and sent to the second conveying path B by the switching claw 2 so that the sheet is turned upside down.
And driven rollers 9. At this time, the leading end of the switching claw 2 is pressed while overlapping the reversing guide member 23, and the sheet is conveyed so as to push the switching claw 2 away.

The main control plate 31 is provided with a reversing entrance sensor S4.
When the trailing edge of the sheet passes through the switching claw 2 based on the output signal, the rotation direction of the motor M2 is switched to reverse the transport roller 8. Therefore, the sheet is transported to the third transport path C side by the transport roller 8 and the driven roller 9, and
The sheet is conveyed through the first conveyance path A by the driven roller 4 and the driven roller 17 and is discharged to the sheet discharge tray 3 from the sheet discharge port.

The paper surface detection sensor S3 detects the upper surface of the sheets discharged and stacked on the discharge tray 3. The main control plate 31 controls the motor M4 based on the output signal of the paper surface detection sensor S3 to adjust the height of the paper discharge tray 3 so that the upper surface of the paper discharged and stacked on the paper discharge tray 3 always has the above-mentioned paper discharge. Control so that it is at a fixed position with respect to the mouth. Also,
The main control plate 31 sorts the sheets by controlling the motor M3 as needed to shift the sheet discharge tray 3 in a direction (sheet width direction) orthogonal to the sheet conveyance direction. Note that the main control plate 31 controls the motor M6 using the output signal of the sensor S2 so that the sheet ejection claw 13 escapes to a position where the leading end of the sheet does not hit.

FIG. 6 shows a part of the processing flow of the main control board 31. The paper surface detection sensor S3 detects the upper surface of the stacked sheets discharged to the discharge tray 3, and the leading end of the sheet hits the filler 24 when the sheet is discharged, so that the sheet jumps up the filler 24. Therefore, while the filler 24 is being jumped up by the sheet, the sheet surface detection sensor S
3 is turned on and an erroneous determination is made that the upper surface position of the paper on the paper discharge tray 3 is high.

Therefore, in this embodiment, it is usually determined that the upper surface position of the paper on the paper discharge tray 3 is high when the paper surface detection sensor S3 is continuously turned on abnormally continuously for a certain period of time. The certain time is required to be longer than the time from when the sheet hits the filler 24 to when the sheet is completely dropped on the discharge tray 3, and is actually about 3 to 4 seconds, for example.
As for the descending amount of the paper discharge tray 3, after the paper size is recognized, the paper discharge tray 3 is lowered by an amount corresponding to the thickness of each paper.

That is, as shown in FIG. 6, the main control board 31 checks the output signal of the paper surface detection sensor S3, and if the paper surface detection sensor S3 is off, resets the timer to 0 and outputs the output of the paper surface detection sensor S3. Return to signal check. When the paper surface detection sensor S3 is turned on, the main control plate 31 increments the timer by one, and determines whether or not the timer has reached the set value corresponding to the above-mentioned fixed time.

If the timer does not reach the set value, the main control board 31 returns to the check of the output signal of the paper surface detection sensor S3, and when the timer reaches the set value, the image forming apparatus 1 uses the information on the sheet from the image forming apparatus 1 to perform image formation. It recognizes whether the size of the paper discharged from the apparatus 1 is a postcard size or an envelope size. The main control board 31
When the size of the paper discharged from the image forming apparatus 1 is the postcard size, the motor 4 is rotated, for example, for 10 to 15 ms, and the discharge tray 3 is moved to the amount A corresponding to the thickness of the postcard size paper, for example, 2. After lowering by about 3 mm, the motor 4 is stopped to stop the discharge tray 3, and the timer is set to 0.
To return to the check of the output signal of the paper surface detection sensor S3.

When the size of the sheet ejected from the image forming apparatus 1 is the envelope size, the main control plate 31 rotates the motor 4 by, for example, 15 to 20 ms to move the ejection tray 3 to the envelope size sheet. After lowering by an amount B corresponding to the thickness of the sheet, for example, 3 to 4 mm, the motor 4 is stopped to stop the sheet discharge tray 3, and the timer is reset to 0 to check the output signal of the sheet surface detection sensor S3. Return.

When the size of the sheet discharged from the image forming apparatus 1 is neither the postcard size nor the envelope size, the main control plate 31 controls the motor 4 to be, for example, 5 to 10 ms.
After rotating the discharge tray 3 to lower the discharge tray 3 by an amount C corresponding to the thickness of the normal size paper, for example, 1 to 2 mm, the motor 4 is stopped to stop the discharge tray 3, and the timer is reset to 0. Then, the process returns to the check of the output signal of the paper surface detection sensor S3.

As described above, this embodiment is an embodiment of the invention according to claim 1, and is a post-processing apparatus for receiving sheets discharged from the image forming apparatus 1 and stacking the sheets on the discharge tray 3. A main control plate 31 as a paper size recognizing means for recognizing the size of the paper discharged from the image forming apparatus 1 when receiving the paper; A main control plate 31 serving as a discharge tray position control means for lowering the discharge tray 3 by a predetermined amount when the position of the discharge tray 3 after discharging the paper is too high; Is the paper size recognition means 3
1 recognizes the postcard size as the paper size, the discharge tray 3 after the paper discharge of the image forming apparatus 1
When the position is too high, the amount by which the discharge tray 3 is lowered is made larger than the predetermined amount, so that the stackability of the postcard-size sheets on the discharge tray can be improved, and the normal operation from the image forming apparatus can be performed. It is possible to eliminate the problem that the paper is jammed in the paper discharge port or the paper falls from the paper discharge tray when the paper having the postcard size thicker than the paper is discharged.

This embodiment is an embodiment of the second aspect of the present invention. In the post-processing apparatus according to the first aspect, the discharge tray position control means 31 and the paper size recognition means 31 When the size of the envelope is recognized as the size, if the position of the paper discharge tray 3 after the paper discharge of the image forming apparatus 1 is too high, the paper discharge tray 3
The amount by which the paper size is lowered is made larger than when the paper size recognition means 31 recognizes the postcard size as the paper size. The problem that the paper is jammed or the paper drops from the paper discharge tray can be solved.

FIG. 7 shows a part of the processing flow of the main control board in another embodiment of the present invention. This embodiment is
This is an embodiment of the invention according to claims 3 and 4, in which the main control board 31 executes the processing flow shown in FIG. 7 instead of the processing flow shown in FIG. In this embodiment, every time a sheet discharged to the sheet discharge tray 3 is detected by the sheet discharge sensor S5, the sheet discharge tray 3 is lowered by a set amount so that the state of the sheet surface detection sensor S3 is not observed. You.

That is, as shown in FIG. 7, the main control plate 31 checks the output signal of the paper discharge sensor S5 to determine whether or not the paper discharge sensor S5 is turned on, and turns off the paper discharge sensor S5. Then, it is repeatedly determined whether or not the sheet ejection sensor S5 is turned on. When the paper ejection sensor S5 is turned on, the main control plate 31 checks the output signal of the paper ejection sensor S5 to determine whether or not the paper ejection sensor S5 is turned off, and keeps the paper ejection sensor S5 on. If so, it is repeatedly determined whether or not the discharge sensor S5 has been turned off.

When the paper discharge sensor S5 is turned off, the main control board 31 determines that the paper has been discharged to the paper discharge tray 3, and recognizes the paper size in the same manner as in the above embodiment, and then recognizes the paper size. Is rotated by the set time, so that the output tray 3
Is lowered by the set amount, the motor 4 is stopped, and the process returns to the determination of whether or not the discharge sensor S5 is turned on.

As described above, this embodiment is an embodiment of the third aspect of the present invention, and is a post-processing apparatus for receiving sheets discharged from the image forming apparatus 1 and stacking the sheets on the discharge tray 3. And a main control plate 31 as a paper size recognizing means for recognizing the size of the paper when receiving the paper discharged from the image forming apparatus 1, and the paper size recognizing means 31 recognizing the postcard size as the paper size. A main control plate 31 serving as a discharge tray position control means for lowering the discharge tray 3 by a fixed amount each time a sheet is discharged from the image forming apparatus 1 irrespective of the position of the discharge tray 3. Therefore, the timing of lowering the sheet discharge tray for an image forming apparatus having a high image processing ability can be advanced, and this is a case where the image processing capacity of the image forming apparatus is low. If the image forming apparatus has a high image processing capacity, the paper output port may be jammed or the paper may drop from the paper output tray if a postcard size sheet thicker than normal paper is ejected from the image forming apparatus. Or the problem of being able to do so can be eliminated.

Further, this embodiment is an embodiment of the invention according to claim 4, and in the post-processing apparatus according to claim 3, the paper discharge tray position control means 31 is provided with the paper size recognition means 31. When the envelope size is recognized as the paper size, the amount by which the paper discharge tray 3 is lowered every time paper is discharged from the image forming apparatus 1 is set to be smaller than when the paper size recognition unit 31 recognizes the postcard size as the paper size. Therefore, not only when the processing capacity of the image forming apparatus is low but also when the processing capacity of the image forming apparatus is high, the discharge is performed when the envelope-size sheet thicker than the normal sheet is discharged from the image forming apparatus. It is possible to eliminate the problem that the paper is jammed in the paper slot or the paper drops from the paper discharge tray. The present invention is not limited to the above embodiment, and can be applied to, for example, an image forming apparatus such as a printer.

[0044]

As described above, according to the first aspect of the present invention, in a post-processing apparatus for receiving sheets discharged from an image forming apparatus and stacking the sheets on a discharge tray, the sheet is discharged from the image forming apparatus. Paper size recognizing means for recognizing the size of the paper when receiving the paper, and output from the output signal of the paper size recognizing means when the position of the paper discharge tray after paper discharge of the image forming apparatus is too high. And a discharge tray position control means for lowering the paper tray by a predetermined amount. When the paper size recognition means recognizes the postcard size as the paper size, the discharge tray position control means controls the image forming apparatus after discharging the paper. When the position of the paper discharge tray is too high, the amount by which the paper discharge tray is lowered is made larger than the predetermined amount, so that the image forming apparatus is thicker than normal paper. It can be paper book size sheet from the sheet discharge tray or a paper jam in the discharge port when it is discharged to eliminate the inconvenience that or fall.

According to a second aspect of the present invention, in the post-processing apparatus according to the first aspect, when the sheet size recognizing unit recognizes the envelope size as the sheet size, the image forming apparatus may control the image forming apparatus. When the position of the discharge tray after the discharge of the sheet is too high, the amount by which the discharge tray is lowered is made larger than when the paper size recognition unit recognizes the postcard size as the paper size. It is possible to solve the problem that when a sheet having an envelope size thicker than a normal sheet is ejected, the sheet is jammed in the sheet ejection outlet or the sheet falls from the sheet ejection tray.

According to the third aspect of the present invention, in a post-processing device for receiving sheets discharged from an image forming apparatus and stacking the sheets on a sheet discharge tray, when receiving the sheets discharged from the image forming apparatus, Paper size recognizing means for recognizing the size of the paper; and when the paper size recognizing means recognizes the postcard size as the paper size, every time paper is discharged from the image forming apparatus regardless of the position of the paper discharge tray. A discharge tray position control means for lowering the discharge tray by a certain amount, so that not only when the image processing capacity of the image forming apparatus is low but also when the image processing capacity of the image forming apparatus is high, Resolves the problem that paper is jammed in the paper exit and drops from the paper output tray when paper with a postcard size thicker than normal paper is ejected from Rukoto can.

According to a fourth aspect of the present invention, in the post-processing apparatus according to the third aspect, when the sheet size recognizing unit recognizes an envelope size as a sheet size, the image forming apparatus may control the image forming apparatus. Each time a sheet is discharged from the printer, the amount by which the discharge tray is lowered every time is larger than when the paper size recognition unit recognizes the postcard size as the paper size, so that only when the processing capacity of the image forming apparatus is low, Even when the image forming apparatus has a high processing capacity, if the image forming apparatus ejects a sheet having an envelope size that is thicker than a normal sheet, the sheet may become jammed in the discharge port or the sheet may drop from the discharge tray. Can be solved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing the embodiment.

FIG. 3 is a side view showing the staple unit of the embodiment.

FIG. 4 is a sectional view showing the stipple unit of the embodiment.

FIG. 5 is an enlarged cross-sectional view showing a sheet discharge unit of the embodiment.

FIG. 6 is a flowchart showing a part of a processing flow of a main control board in the embodiment.

FIG. 7 is a flowchart showing a part of a processing flow of a main control board according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Discharge tray 31 Main control plate M1 to M7 Motor SOL1 Solenoid S1 to S5 Sensor

Claims (4)

[Claims] A post-processing device for receiving paper discharged from the image forming apparatus and stacking the paper on a paper discharge tray, wherein a sheet for recognizing the size of the paper when receiving the paper discharged from the image forming apparatus is received. Size recognition means, and discharge tray position control means for lowering the discharge tray by a predetermined amount when the position of the discharge tray after discharging the paper of the image forming apparatus is too high based on an output signal of the paper size recognition means; The paper ejection tray position control means is provided when the paper size recognition means recognizes a postcard size as a paper size, and when the paper ejection tray is too high after ejection of the paper of the image forming apparatus, the paper ejection tray is controlled. A post-processing device, wherein an amount of lowering is made larger than the predetermined amount. 2. A post-processing apparatus according to claim 1, wherein said paper discharge tray position control means controls said paper discharge after paper discharge of said image forming apparatus when said paper size recognition means recognizes an envelope size as a paper size. A post-processing apparatus, wherein when the position of the tray is too high, the amount by which the discharge tray is lowered is made larger than when the paper size recognition means recognizes a postcard size as a paper size. 3. A post-processing device for receiving paper discharged from an image forming apparatus and stacking the paper on a paper discharge tray, wherein a sheet for recognizing the size of the paper when receiving the paper discharged from the image forming apparatus. When the paper size recognition means recognizes a postcard size as a paper size, the paper discharge tray is lowered by a fixed amount every time paper is discharged from the image forming apparatus regardless of the position of the paper discharge tray. And a discharge tray position control means for controlling the position of the discharge tray. 4. The post-processing apparatus according to claim 3, wherein said paper discharge tray position control means is provided for each time paper is discharged from said image forming apparatus when said paper size recognition means recognizes an envelope size as a paper size. A post-processing apparatus wherein the amount of lowering the paper discharge tray each time is larger than when the paper size recognition means recognizes a postcard size as a paper size.