JP2002128321A - Sheet detecting device, sheet postprocessing device and image forming device having it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a sheet even when a thin sheet with low stiffness such as a second original drawing is not conveyed to a predetermined position. SOLUTION: In this sheet detecting device 20, one detecting means 24 detects actuations of a plurality of sheet actuating members 21 and 22 that are arranged in the sheet conveying direction and are actuated by being pressed by a sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet detecting apparatus for detecting a sheet, a sheet post-processing apparatus having the sheet detecting apparatus for processing a sheet detected by the sheet detecting apparatus, and forming an image on the sheet. And a sheet post-processing apparatus for processing the sheet.

[0002]

2. Description of the Related Art Conventionally, image forming apparatuses for forming an image on a sheet include copying machines, printing machines, laser beam printers, and the like.
There are facsimile machines and multifunction machines of these machines. FIG.
1 shows a copying machine 300 as an example of an image forming apparatus. A sheet post-processing apparatus (finisher) 200 is connected to the side of the apparatus main body 360 of the copying machine 300. A recirculating document feeder (RDF) 305 is mounted on the upper part of the apparatus main body 360. As shown in FIG. 19, a sheet stacking alignment device 290 is incorporated in the sheet post-processing device 200.

[0003] As shown in FIG. 18, a recirculating document feeder 305 of a copying machine 300 automatically feeds a document to an image reading unit 306. The image reading unit 306 reads the image of the sent original. Then, a controller (not shown) sends a signal to the laser oscillator according to the read image information. The laser oscillator emits laser light.

The laser beam is reflected by a rotating polygon mirror 309, and is turned back by a plurality of reflecting mirrors 310 to irradiate an electrophotographic photosensitive drum 312 whose surface is uniformly charged in advance. . As a result, an electrostatic latent image is formed on the photosensitive drum 312. After the electrostatic latent image on the photosensitive drum 312 is developed by the developing device 311, it becomes a toner image with toner.

On the other hand, a sheet on which an image is formed is picked up by sheet rollers 351 and 35 by a pickup roller 313.
2 and is conveyed to the separation roller pair 307 as appropriate. The sheets include plain paper, OHP (overhead projector) sheets, cardboard, and postcards.

[0006] The sheet is separated by a pair of separation rollers 307.
Separated one by one, the pair of pre-registration rollers 316, 3
17 is supplied. Then, the sheet is transferred to the pair of registration rollers 31 by the pair of pre-registration rollers 316 and 317.
4,315. Registration roller pair 314,3
15 corrects the skew of the sheet, and feeds the sheet between the photosensitive drum 312 and a transfer device facing the photosensitive drum 312 in synchronization with the rotation of the photosensitive drum 312. At this time, the toner image formed on the photosensitive drum 312 is transferred to a sheet by the transfer device.

Thereafter, the sheet is fixed to a pair of fixing rollers 321,
The toner image is permanently fixed by being heated and pressed by the fixing roller pair 321 and 322. An upper fixing claw 323 and a lower fixing claw 324 are in contact with the fixing roller pairs 321 and 322, respectively.
322. The separated sheet is conveyed to the outside of the apparatus main body 360 of the copying machine 300 by the discharge roller pair 329, and is guided to the sheet post-processing apparatus 200 connected to the apparatus main body 360 of the copying machine 300.

As shown in FIG. 19, the connection between the sheet processing apparatus 200 and the apparatus main body 360 of the copying machine 300 is performed by a lock arm 202 provided on the upper part of the sheet processing apparatus 200.
And the holding member 203 attached to the copying machine 300
This is done by engaging with. By this connection, the sheet processing apparatus 200 is connected to the apparatus main body 360 of the copying machine 300.
Is positioned. Further, the sheet post-processing apparatus 200 includes:
It is supported by a slide unit 204 fixed to the copying machine 300, and can move in the sheet discharging direction (the direction of arrow Y in FIG. 19).

In the apparatus main body 360 of the copying machine 300 or the sheet post-processing apparatus 200, a sheet conveyance failure or the like occurs.
When the sheet staying in the apparatus main body 360 or the sheet post-processing apparatus 200 is to be taken out, the lock arm 202 is rotated in the direction of the arrow X so that the sheet post-processing apparatus 2 is rotated.
00 can be separated from the apparatus main body 360. Thus, the attachment and detachment of the sheet post-processing apparatus 200 to and from the apparatus main body 360 of the copying machine 300 can be performed smoothly.

The apparatus body 36 is driven by the discharge roller pair 329.
The sheet discharged from 0 is guided further downstream by a sheet path 207 formed by the upper guide 205 and the lower guide 206 in the sheet post-processing apparatus 200. The sheet passage detection sensor 208 detects a passing sheet, a staying sheet, and the like. The discharge roller pair 209 includes a discharge roller 209a and a discharge roller 209b pressed by the discharge roller 209a, and discharges the sheet guided along the sheet path 207 to the post-processing tray 230.

The post-processing tray 230 is used as an intermediate tray for temporarily accumulating sheets and performing alignment and stabilization. The stapler 210 is mounted on the post-processing tray 23.
The staple binding process for the sheet bundle on the zeroth sheet is performed. The sheet bundle discharge belt 260 is connected to the post-processing tray 2.
The sheets on the sheet 30 are conveyed in a bundle and discharged on the stack tray 280 in a bundle.

As shown in FIG. 19, the post-processing tray 230 is inclined about 30 degrees with the downstream side in the sheet discharging direction (left side in FIG. 19) upward and the upstream side in the sheet discharging direction (right side in FIG. 19) downward. are doing. At the lower end of the post-processing tray 230, a sheet rear end stopper 231 is provided. A sheet detection sensor 232 is provided near the sheet rear end stopper 231. Sheet detection sensor 23
Numeral 2 detects the presence or absence of a sheet on the post-processing tray 230. The sheet width aligning device 240 adjusts the width of the sheet bundle stacked on the post-processing tray 230. The sheet bundle discharge belt 260 circulates in a direction to discharge the sheet bundle by receiving a driving rotational force from a motor (not shown), and discharges the sheet bundle stacked on the post-processing tray 230 to the stack tray 280. Has become.

The sheet discharged by the discharge roller pair 209 slides down on the post-processing tray 230 until the rear end of the sheet comes into contact with the sheet rear end stopper 231 by the weight of the sheet and the return butting action of the return roller 250. . At this time, the sheet on the post-processing tray is detected by the sheet detection sensor 232, and a sheet counter for counting the number of sheets to be subjected to post-processing set by the user via an operation unit (not shown) is started.

Next, the sheet width is aligned by the sheet width aligning device 240, and alignment in the sheet width direction is performed. The sheets discharged from the discharge roller pair 209 are sequentially aligned one by one, and are stacked in a predetermined number on the post-processing tray 230 to form a bundle. When, for example, sheet binding is instructed by an operation unit (not shown), the sheet bundle is stapled by the stapler 210 and bound. Finally, the sheet bundle is discharged onto the stack tray 280 by circulation of the sheet bundle discharge belt 260. At this time, the sheet detection sensor 232 detects that there is no sheet on the post-processing tray, clears the count of the number of sheets to be post-processed, and enables the next post-processing.

[0015]

However, in the conventional sheet post-processing apparatus 200, when a thin sheet as shown in the second original drawing is to be pulled back on the post-processing tray to the sheet rear end stopper by a return means such as a return roller. Since the seat has a weak waist, buckling or entanglement in the return means may occur.

As a method for dealing with such a problem, it has been considered to provide an operation mode dedicated to thin sheets, such as the second original drawing, in which the return means is not operated.

However, the sheet detecting means for detecting the presence or absence of a sheet on the post-processing tray is provided near the sheet rear end stopper so as not to hinder the sheet retraction operation. Therefore, when the return means is not operated, it is necessary to return to the sheet rear end stopper only by the weight of the sheet. In order to return the sheet to the sheet rear end stopper only by its own weight, the inclination angle of the post-processing tray on which the sheets are stacked needs to be 30 ° or more.

In recent years, by reducing the installation area of the apparatus body of the copying machine and the sheet post-processing apparatus, and by omitting the mounting bracket or the self-supporting means of the sheet post-processing apparatus, the reader section and the printer section of the copying machine have been connected. In the meantime, a device having a sheet post-processing device is considered.

Therefore, when the sheet post-processing apparatus is provided between the reader unit and the printer unit of the copying machine by the above-described method of increasing the tray inclination angle,
It becomes necessary to provide a large space between the reader unit and the printer unit of the copying machine.

In view of this, it is conceivable to provide a plurality of sensors on the tray in order to reliably detect the stacking of sheets even when the sheets do not fully return in the state where the inclination angle is small. However, providing a plurality of sensors requires many sensor members, and has a problem such as an increase in cost. Further, since the number of signal processings from a plurality of sensor members also increases by the number of sensors, the control becomes complicated, and there is a problem that the reliability of the apparatus is easily reduced.

(Purpose) According to the present invention, for example, the inclination angle of the post-processing tray on which the sheets are stacked is made gentle, the space in the height direction of the sheet post-processing device is reduced, and the effect of returning the sheets by their own weight is reduced. The object of the present invention is to provide an inexpensive and highly reliable sheet detection device that can detect a sheet even when a thin sheet having a weak stiffness as in the second original drawing is not conveyed to a predetermined position. I have.

It is another object of the present invention to provide a sheet post-processing device which includes the sheet detecting device and processes a sheet detected by the sheet detecting device.

Still another object of the present invention is to provide an image forming apparatus in which an image is formed on a sheet and the sheet is processed by a sheet post-processing apparatus.

[0024]

In order to achieve the above object, a sheet detecting apparatus according to the present invention comprises a plurality of sheet actuating members which are arranged in a sheet conveying direction and actuated by being pressed by the sheet. The detection is performed by two detection means.

The sheet detecting device of the present invention has a detecting operation member which is activated when any one of the plurality of sheet operating members is pressed by the sheet and operates, and the detecting means is configured to detect the detecting operation. The operation of the operation member is detected.

The detection operation member of the sheet detection device of the present invention is a member separate from the plurality of sheet operation members.

[0027] The detection operation member of the sheet detection apparatus of the present invention is provided on one of the plurality of sheet operation members, and the one sheet operation member is operated by being pressed by the sheet. In addition, it operates when another sheet operating member is pressed by the sheet.

The sheet operating member of the sheet detecting device according to the present invention is a lever which is rotated by being pressed by the sheet.

The detecting means of the sheet detecting device of the present invention is a photo sensor.

In order to achieve the above object, a sheet post-processing apparatus according to the present invention comprises:
Sheet stacking means for receiving a sheet, sheet receiving means for receiving the sheet fed to the sheet loading means on the downstream side in the direction in which the sheet is fed, and the sheet fed to the sheet loading means Sheet conveying means for abutting and conveying the sheet to the sheet receiving means, wherein the plurality of sheet operating members of the sheet detecting device are arranged upstream in a direction in which the sheet is fed from the sheet receiving means. ing.

In order to achieve the above object, a sheet post-processing apparatus according to the present invention comprises:
Sheet stacking means for receiving a sheet, sheet receiving means for receiving the sheet fed to the sheet loading means on the downstream side in the direction in which the sheet is fed, and facing the sheet loading means Sheet guide means for guiding a downstream end portion of the sheet to the sheet receiving means, and sheet conveying means for abutting and conveying the sheet fed to the sheet stacking means against the sheet receiving means, The plurality of sheet operating members of the sheet detecting device are arranged upstream in a direction in which the sheet is fed from the sheet receiving means, and at least one sheet operating member is arranged at a position facing the sheet guiding means. Has been established.

In order to achieve the above object, an image forming apparatus according to the present invention comprises an image forming means for forming an image on a sheet, and any one of the above sheet detecting devices.

In order to achieve the above object, an image forming apparatus according to the present invention comprises: an image forming means for forming an image on a sheet; and any one of the sheets for processing the sheet on which an image has been formed by the image forming means. And a post-processing device.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a sheet post-processing apparatus provided with a sheet detecting apparatus according to an embodiment of the present invention and a copying machine which is an example of an image forming apparatus equipped with the sheet post-processing apparatus in a main body of the apparatus will be described. This will be described with reference to the drawings. In addition, the sheet detection device according to the embodiment of the present invention and the sheet post-processing device provided with the sheet detection device may be provided not only in a copying machine but also in a device body such as a printer, a facsimile, and a multifunction peripheral thereof. Yes, it is not provided only in the copying machine.

(Copier) Referring to FIG.
The document is automatically sent to the image reading unit 102 by the circulating document feeder 105 and the image of the document is read by the image reading unit 102. Then, a signal is sent to the laser oscillator by a controller (not shown) according to the read image information, and the laser oscillator emits a laser beam.

The laser light is reflected by a rotating polygon mirror 109 and further turned back by a reflection mirror 110 to irradiate an electrophotographic photosensitive drum (image forming means) 112 whose surface is uniformly charged in advance. Is done.
As a result, an electrostatic latent image is formed on the photosensitive drum 112. After the electrostatic latent image on the photoconductor drum 112 is developed by the developing device 111, the electrostatic latent image becomes a toner image by toner.

On the other hand, the sheet on which an image is formed is picked up by a pick-up roller 113 for sheet cassettes 151 and 15.
2, 153 and 154, are separated one by one by a separation roller pair 107 and supplied to a pair of pre-registration rollers 116 and 117. The sheet has
There are plain paper, OHP (overhead projector) sheets, cardboard, and postcards.

Then, the sheet is a pair of pre-registration rollers 1
The sheet is conveyed to a pair of registration rollers 114 and 115 by the rollers 16 and 117. Further, the skew of the sheet is corrected by the pair of registration rollers 114 and 115, and the sheet is fed between the photosensitive drum 112 and the transfer device 118 facing the photosensitive drum 112 in synchronization with the rotation of the photosensitive drum 112. At this time, the toner image formed on the photosensitive drum 112 is transferred to the sheet by the transfer device 118.

Thereafter, the sheet is fixed to the fixing roller pair 121,
The toner image is guided to the fixing roller 122 and subjected to heat and pressure by the fixing roller pairs 121 and 122 to permanently fix the toner image on the sheet. An upper fixing separating claw 123 and a lower fixing separating claw 124 are in contact with the fixing roller pairs 121 and 122, respectively, whereby the sheet is separated from the fixing roller pairs 121 and 122. The separated sheet is conveyed to the upper part of the printer unit 101 by the discharge roller pair 129, and is guided to the sheet post-processing apparatus 1.

The sheet S discharged from the discharge roller pair 129 is sent further downstream by a sheet path 7 (see FIG. 2) formed by the upper guide 5 and the lower guide 6 in the sheet post-processing apparatus 1. The sheet passage detection sensor 8 detects a passing sheet, a staying sheet, and the like. The discharge roller pair 9 includes the discharge roller 9
a and a discharge roller 9b pressed against the discharge roller 9a.

The post-processing tray 30 is used as an intermediate tray for temporarily accumulating the sheets S and performing at least one operation out of alignment, stapling, and the like. The stapler 10 performs a stapling process by driving staples into a sheet bundle on the post-processing tray 30. The stapler 10 has almost the same configuration as that of an electric or motor-driven automatic stapler, and binds sheets. The sheet bundle discharge belt 60 is configured to store the sheets S stacked on the post-processing tray 30.
Are conveyed in a bundle and discharged in a stack onto the stack tray 80.

(Sheet Post-Processing Apparatus) In FIGS. 2 and 3, the post-processing tray (sheet stacking means) 30 of the sheet post-processing apparatus 1 discharges the sheet upward in the sheet discharging direction on the downstream side (right side in FIG. 2). The tray is inclined about 20 degrees with the upstream side (left side in FIG. 2) facing downward. At the end of the post-processing tray 30 on the upstream side in the sheet discharging direction, a sheet rear end stopper (sheet receiving means) 31 is provided. The sheet discharged by the discharge roller pair 9 is transferred to the post-processing tray 30 until the rear end of the sheet comes into contact with the sheet rear end stopper 31 by the action of the return arm roller (sheet conveying means) 50.
Downhill above. The sheet discharged by the discharge roller pair 9 is fed into the post-processing tray 30 by the weight of the sheet and the return arm roller 50. Therefore, the sheet is fed downstream in the sheet discharge direction. And the upstream side in the sheet discharge direction is
It is on the downstream side where the sheet is fed.

The post-processing tray 30 is provided with a sheet detecting unit (sheet detecting device) 20, a sheet width aligning device 40, a sheet bundle discharging belt 60, and the like.

In FIGS. 2 to 6, the sheet detecting unit 20 is a lever (sheet operating member) which is operated by being pressed by the sheet S near the downstream end (right side in FIG. 2) of the post-processing tray 30 in the sheet discharging direction. 21, a lever (sheet operating member) 22 that is pressed by the sheet S in the vicinity of the sheet rear end stopper 31 and operates, and levers 21 and 22.
A sensor flag (detection operating member) 23 that intercepts the photo sensor (detection means) 24 and is interlocked with the sheet detection sensor plate 25 is rotatably attached to the sheet detection sensor plate 25.

A spring 26 (FIGS. 3 and 4) as an urging member is wound around the sheet detecting lever 21. The spring 26 lifts the tip 21b side of the lever 21 upward with a predetermined load as shown in FIG. 2 and 3, the leading end 21b of the lever 21 is located on the downstream side in the sheet discharge direction to a position farther than the point (A) where the rear end of the sheet discharged from the discharge roller pair 9 lands on the post-processing tray 30. Is growing. As shown in FIGS. 2, 5, and 6, the hook portion 21c of the lever 21 is
The engaging portion 32 of the lever 21 is engaged with the engaging portion 32 so as to maintain the rising amount of the lever 21 at a predetermined amount. Therefore, lever 21
The leading end 21b of the sheet is not hindered when the rear end of the sheet is brought into contact with the sheet rear end stopper 31 by the action of the return arm roller 50.

A spring 27 (FIGS. 3 and 4) as an urging member is wound around the sensor flag 23. Spring 27
Lifts the connecting arm 23a of the sensor flag 23 and the rotating end side of the lever 22 via the connecting arm 23a with a predetermined load. As a result, lever 2
When the sheets 1 and 22 are not pressed by the sheet, the sensor light blocking portion 23b of the sensor flag 23
No. 4 is out of the detection area.

In the sheet width aligning device 40, the alignment member 41 on the front side and the alignment member 42 on the back side independently move in the direction orthogonal to the sheet conveying direction (the sheet width direction) to reduce the width of the sheet S. They are aligned.

The sheet bundle discharge belt 60 is rotated clockwise by receiving a driving torque from a motor (not shown), and discharges the sheet bundle stacked on the post-processing tray 30 onto the stack tray 80. .

Next, the stack tray 80 will be described with reference to FIG. The stack tray 80 is supported by the apparatus main body 103 of the copier so as to be able to move up and down by a support member (not shown) and a rail member that slidably supports the support member, and is moved up and down by driving means including a motor. .

The stack tray 80 is provided with a sheet presence / absence detection sensor 81. The sheet presence / absence detection sensor 81 does not accept a new job when sheets are already stacked on the stack tray 80. The sheet surface height detection sensor 82 detects the height of the stacked sheet bundle and adjusts the height of the stacking surface on the stack tray 80 with respect to the post-processing tray 30 to a predetermined height.

The sheet trailing edge pressing member 83 moves up and down from the guide surface 84 in conjunction with the elevating operation of the stack tray 80 to hold the trailing edge of the sheet bundle stacked on the stack tray 80, and to discharge the sheet bundle. In the sheet discharge direction.

Next, the configuration and operation of the sheet detection unit 20 will be described with reference to FIGS. Lever 2
Numeral 1 is attached to the sheet detection sensor plate 25 so as to be rotatable around a rotation center axis X on the sheet detection sensor plate 25. A spring 26 is provided on the rotation center axis X. The spring 26 lifts the distal end 21b side of the lever 21 upward with a predetermined load as shown in FIG.

The lever 22 is pivoted about the rotation center axis Y on the sheet detection sensor plate 25,
Is mounted to be rotatable.

The sensor flag 23 is rotatably mounted on the sheet detection sensor plate 25 with the rotation center axis Z on the sheet detection sensor plate 25 as a fulcrum. A spring 27 is provided on the rotation center axis Z. The spring 27 includes a connecting arm 23a of the sensor flag 23 and a connecting arm 23a.
And the pivot end side of the lever 22 is lifted upward with a predetermined load. As a result, when the levers 21 and 22 are not pressed by the sheet, the sensor light shielding portion 23b of the sensor flag 23 is retracted outside the detection area of the photo sensor 24.

The post-processing tray 30 is driven by the discharge roller pair 9.
The sheet discharged above rests on the tip 21 b of the lever 21. Then, due to the weight of the sheet, the lever 21 rotates in the direction of arrow D in FIG. 5 and pushes the interlocking arm 23a of the sensor flag 23 with the pressing surface 21a, and the sensor flag 23 in the direction of arrow E in FIGS. Is rotated. As shown in FIG. 6, at the same time, the light shielding portion 23b of the sensor flag 23 shields the photo sensor 24 from light. Light shielding part 2 of sensor flag 23
3b shields the photosensor 24, the photosensor 2
No. 4 detects that the sheet S is on the post-processing tray 30. At this time, the lever 22 rotates in the direction of the arrow F in FIG. 5 by its own weight, and the pressing surface 22a is received by the interlocking arm 23a of the sensor flag 23 and stops rotating.

Thereafter, when the sheet discharged onto the post-processing tray 30 is received by the sheet rear end stopper 31, the sheet end pushes the detecting portion 22b of the lever 22. The lever 22 further pivots in the direction of arrow F as shown in FIG.
Push the interlock arm 23a of FIG.
Is further rotated in the direction of arrow E.

Next, a normal post-processing operation will be described with reference to FIGS.
It will be described based on. In FIG. 1, a printer unit 101
Is guided to the sheet post-processing apparatus 1. Discharge roller pair 129 of printer unit 101
In FIG. 2, the sheet S discharged from the sheet passes through the sheet passage detection sensor 8 while passing through the sheet path 7 formed by the upper guide 5 and the lower guide 6 in the sheet post-processing apparatus 1, and is a discharge unit. The sheet is discharged onto the post-processing tray 30 by the discharge roller pair 9. After a predetermined time has passed from the time when the rear end of the sheet S has passed through the sheet passage detection sensor 8, the return arm roller 50 starts rotating in the direction of arrow C in FIG.

When the sheet lands on the post-processing tray 30, the lever 21 of the sheet detection unit 20 rotates in the direction of arrow D in FIG. 7, and the sensor flag 23 rotates in the direction of arrow E in FIG. Then, the light shielding portion 23b of the sensor flag 23
Shields the photosensor 24 from light.

When the light shielding portion 23b of the sensor flag 23 shields the photo sensor 24, it is detected by the photo sensor 24 that the sheets are stacked on the post-processing tray 30, and the post-processing set by the operation unit (not shown) is performed. A counter (not shown) that counts the number of sheets S to be started starts counting.

Then, the return arm roller 50 makes one rotation in the direction of arrow C in FIG. While the return arm roller 50 makes one rotation, the sheet S on the post-processing tray 30 is pulled back to the sheet rear end stopper 31, and the rear end is abutted against the sheet rear end stopper 31 to align the sheet in the sheet conveyance direction. Complete. At this time, the lever 22 rotates in the direction of arrow F in FIG. 8, and the lever 22 retracts outside the sheet rear end stopper 31.

Thereafter, the alignment plate 4 of the sheet width alignment device 40
1, 42 operate to perform alignment in the sheet width direction. The sheets S discharged from the discharge roller pair 9 are sequentially aligned one by one, and are stacked in a predetermined number on the post-processing tray 30 to form a bundle. For example, when binding is instructed by a user using an operation unit (not shown), the sheet bundle is stapled by a stapler 10 (see FIG. 10) and bound. Finally, the sheet bundle is discharged onto the stack tray 80 by circulation of the left rotation (left rotation in FIG. 9) of the hook portion 61 of the sheet bundle discharge belt 60 as shown in FIG.

When the sheet bundle is discharged onto the stack tray 80, the lever 21 of the sheet detection unit 20 returns to the direction of arrow G in FIG. 9 and the lever 22 returns to the direction of arrow H in FIG. 23 rotates in the direction of arrow I in FIG. Then, the light shielding portion 23b of the sensor flag 23 retreats outside the light shielding region of the photo sensor 24.

When the light-shielding portion 23b of the sensor flag 23 retreats outside the light-shielding area of the photo sensor 24, the sheet is not on the post-processing tray 30, and the counter (not shown) for counting the number of sheets is cleared. You. Then, the sheet post-processing device 1 performs the following post-processing.

Therefore, the sheet post-processing apparatus 1 of the present embodiment is provided with a guide portion (sheet guiding means) 33 for guiding the sheet S to the sheet rear end stopper 31 by the return arm roller 50 so as to be pulled back to the sheet rear end stopper 31. The lever 22 operates reliably within the restraint space formed by the rear end stopper 31.

For example, regardless of whether the sheet S is greatly curled or stacked on the post-processing tray 30, the sheet is pulled back to the sheet rear end stopper 31 by the return arm roller 50, and the rear end of the sheet is End stopper 31
And the sheet trailing end stopper 31 are restrained. Therefore, the sheet detection unit 20 can detect the presence or absence of a sheet even when a large curled sheet is stacked on the post-processing tray 30.

Next, the post-processing operation of the thin sheet S1 such as the second original drawing will be described with reference to FIGS. When the user selects the second original drawing mode using an operation unit (not shown), the sheet S1 on which an image is formed by the printer unit 101 in FIG. 1 is guided to the sheet post-processing apparatus 1. Printer unit 1
01 output from the discharge roller pair 129
Is an upper guide 5 in the sheet post-processing apparatus 1 in FIG.
The sheet passes through a sheet passage detection sensor 8 while passing through a sheet path 7 formed by the lower guide 6 and is discharged onto a post-processing tray 30 by a discharge roller pair 9. At this time, the return arm roller 50 is stopped at a predetermined stop position so as not to return the thin sheet S1 to the sheet rear end stopper 31. The sheet S1 discharged onto the post-processing tray 30 is stacked on the post-processing tray without returning to the sheet rear end stopper 31.

For the sheet S1 on the post-processing tray, the lever 21 of the sheet detection unit 20 is turned in the direction of arrow D in FIG. 10, and the sensor flag 23 is turned in the direction of arrow E in FIG. Then, the light shielding portion 23b of the sensor flag 23 shields the photo sensor 24 from light.

When the light shielding portion 23b of the sensor flag 23 shields the photo sensor 24, the photo sensor 24
1 is detected on the post-processing tray 30. The counter starts counting the number of sheets S1 to be subjected to post-processing set by an operation unit (not shown).

When a predetermined number of sheets S1 sequentially discharged from the discharge roller pair 9 are stacked on the post-processing tray 30 and formed into a bundle, as shown in FIG. It is pushed and discharged onto the stack tray 80 by the circulation.

When the sheet bundle is discharged onto the stack tray 80, the lever 21 of the sheet detection unit 20 is moved to the position shown in FIG.
The sensor flag 23 is turned back in the direction of arrow G,
In the direction of arrow I. And the sensor flag 2
The third light-shielding portion 23b retracts outside the light-shielding area of the sensor 24.

When the light shielding portion 23b of the sensor flag 23 retreats outside the light shielding area of the photo sensor 24, the sheet is not on the post-processing tray 30, and the counter (not shown) for counting the number of sheets is cleared. You. Then, the sheet post-processing device 1 performs the following post-processing.

Therefore, in the sheet detecting unit 20 of the present embodiment, the return arm roller 50 is
Even when the thin sheet is not pulled back to the sheet rear end stopper 31 as in the second original drawing above, the presence or absence of the sheet discharged onto the post-processing tray 30 can be detected.

(Sheet Detection Unit of Another Embodiment) The sheet detection unit 20 of the above-described embodiment
1, a lever 22, and a sensor flag 23 that interlocks with the levers 21 and 22 and shields the photosensor 24 from light, so that the downstream side of the post-processing tray 30 in the sheet discharging direction (the right side in FIG. 2)
The sheet S is detected near the end and near the sheet rear end stopper 31. The sheet detection unit (sheet detection device) 70 shown in FIGS. 12 to 14 and the sheet detection unit (sheet detection unit) shown in FIGS. (Apparatus) 90.

That is, the sheet detection unit 20 operates the photo sensor 24 by the sensor flag 23 which is a member different from the levers 21 and 22. On the other hand, the sheet detection units 70 and 90
One of the levers (sheet operating members) 72, 92 is pressed by the sheet to operate, and the other lever (sheet operating member) 71, 91 is also operated when pressed by the sheet to operate. (Detection means) 74, 9
4 is also activated. Therefore, the sheet detection units 70 and 90 are connected to one of the sheet detection levers 7.
Since the sensors 2 and 92 are also used as the sensor flag 23, the structure is simpler than the sheet detection unit 20 of the above-described embodiment.

First, the configuration and operation of the sheet detection unit 70 shown in FIGS. 12 to 14 will be described. Lever 7
Reference numeral 1 denotes an operation which is performed by being pressed by the sheet S near the downstream end of the post-processing tray 30 in the sheet discharging direction, and a lever 72 which is operated by being pressed by the sheet S near the sheet rear end stopper 31.

The lever 71 is rotatably attached to the sheet detection sensor plate 75 with the rotation center axis X on the sheet detection sensor plate 75 as a fulcrum. A spring 76 as an urging means is provided on the rotation center axis X. This spring 76
FIG. 13 shows a state in which the tip 71b side of the lever 71 is
It is lifted up as shown.

The lever 72 is pivoted about the rotation center axis Y on the sheet detection sensor plate 75,
Is mounted to be rotatable. For the rotation center axis Y,
A spring 77 as an urging means is provided. Spring 77
As shown in FIG. 13, the turning end side of the lever 72 is lifted upward with a predetermined load, and the connecting arm (detection operating member) 72a is pressed against the pressing surface 71a. Further, the spring 77 is connected to the sensor light shielding portion 7 of the lever 72.
2c (detection operating member) is retracted outside the detection area of the photo sensor 74.

The post-processing tray 30 is driven by the discharge roller pair 9.
The sheet S discharged upward is a tip 71 b of the lever 71.
On. Then, depending on the weight of the sheet S, the lever 71
Rotates in the direction of arrow D in FIG. 13 and pushes the interlocking arm 72a of the lever 72 downward in FIG. 13 with the pressing surface 71a. Then, the lever 72 is turned to the arrow F in FIGS.
The lever 72 is rotated in the direction. At the same time, the sensor light shield 72c of the lever 72 shields the photo sensor 74 from light. When the sensor light-shielding portion 72c of the lever 72 shields the photosensor 74, the photosensor 74 detects that the sheet S is on the post-processing tray 30.

Thereafter, the sheet discharged onto the post-processing tray 30 is aligned by the sheet trailing end stopper 31, and the sheet end pushes the detecting portion 72b of the lever 72. Lever 72
Rotates further in the direction of arrow F in FIG.

Next, the configuration and operation of the sheet detection unit 90 shown in FIGS. 15 to 17 will be described. Lever 9
Reference numeral 1 denotes an operation which is performed by being pressed by the sheet S near the downstream end of the post-processing tray 30 in the sheet discharge direction, and a lever 92 which is operated by being pressed by the sheet S near the sheet rear end stopper 31.

The lever 91 is rotatably attached to the sheet detection sensor plate 95 with the rotation center axis X on the sheet detection sensor plate 95 as a fulcrum. The rotation center axis X is provided with a spring 96 as an urging means. This spring 96
FIG. 16 shows a state in which the distal end portion 91b side of the lever 91 is moved under a predetermined load.
It is lifted up as shown. At the same time, the spring 96
Is a sensor light-shielding portion (detection operating member) 91c of the lever 91.
Is retracted out of the detection area of the photo sensor 94.

The lever 92 is pivoted about the rotation center axis Y on the sheet detection sensor plate 95 and
Is mounted to be rotatable. For the rotation center axis Y,
A spring 97 as an urging means is provided. Spring 97
As shown in FIG. 16, the rotating end of the lever 92 is lifted upward by a predetermined load.

The post-processing tray 30 is driven by the discharge roller pair 9.
The sheet S ejected upward is a leading end 91 b of the lever 91.
On. Then, depending on the weight of the sheet, the lever 91
Rotates in the direction of arrow D in FIG. 16, and the sensor light-shielding portion 91c of the lever 91 shields the photosensor 94 from light. Lever 9
When the first sensor light-shielding portion 91c shields the photosensor 94, the photosensor 94 detects that there is a sheet on the post-processing tray 30.

Thereafter, the sheet discharged onto the post-processing tray 30 is aligned by the sheet trailing end stopper 31, and the sheet end pushes the detecting portion 92b of the sheet detecting lever 92.
The lever 92 further rotates in the direction of arrow F in FIG. At the same time, the lever 92 is pressed by the pressing surface 92a.
17 by pressing the interlocking arm 91a (detection operating member) of FIG.
The lever 91 is further rotated in the direction of arrow D.

The sheet detection unit 7 of this embodiment
In the same manner as in the sheet detection unit 20 described above, even if the return arm roller 50 does not pull the thin sheet on the post-processing tray 30 back to the sheet rear end stopper 31 as in the second original drawing, the post-processing tray 30 can also be used. The presence or absence of a sheet discharged to the printer can be detected.

The sheet detection units 20, 70, and 90 of the present embodiment described above allow the sheets discharged to the post-processing tray 30 to come in contact with the levers 22, 72, and 92 first.
Later, even in the case of contact with another lever 21, 71, 91, the lever 22, 72, 92 operates first, and the lever 21, 71, 91 operates later, and finally, both. 6, 14, and 17, and the photosensors 24, 74, and 94 can detect that the sheet has been discharged. It has become.

Further, the sheet detection units 20, 70, and 90 of the present embodiment are arranged such that the sheets discharged to the post-processing tray 30 are connected to both levers 21, 22, 71, 72, 91,
Even if only one of the levers 92 is pressed, the lever pressed by the sheet rotates and the photo sensor 24.74, 94 discharges the sheet onto the post-processing tray. Can be detected.

Therefore, the sheet detection units 20, 70, and 90 of the present embodiment have two levers (21, 21) which are operated by being pressed by the sheet discharged to the post-processing tray 30.
2) Since (71, 72) and (91, 92) are arranged so as not to hinder post-processing such as sheet return and alignment, and are moved in conjunction with each other, the sheets are processed in a post-processing tray. 30 can be reliably detected. Moreover, the two levers (21, 22), (71,
The movements of (72) and (91, 92) are detected by one photosensor 24, 74, 94, so that the structure can be simplified and the cost can be reduced.

Further, the sheet detecting unit 2 of the present embodiment
Reference numerals 0, 70, and 90 denote a first operation which is performed by being pressed by a sheet near the downstream end of the post-processing tray 30 in the sheet discharging direction.
Levers 21, 22, 71 and the sheet rear end stopper 31
The second lever 7 that is pressed by the sheet in the vicinity of
2, 91 and 92, the presence / absence of a sheet stacked on the post-processing tray 30 is detected. Therefore, the area for detecting the presence / absence of the sheet is increased, and the post-processing tray of the sheet post-processing apparatus 1 is detected. By making the inclination angle of the sheet 30 gentler than before, the presence or absence of the sheets stacked on the post-processing tray 30 can be reliably detected even if the return effect due to the weight of the sheets is reduced. At the same time, the thickness of the sheet post-processing apparatus 1 can be reduced, and the height of the copier 100 can be reduced to cope with downsizing.

Although the number of levers is two, three or more levers may be provided on the post-processing tray 30. Also in this case, the movement of the plurality of levers is detected by one photosensor 24, 74, 94. If the number of levers is large, group the levers,
A photo sensor may be provided for each group, and the photo sensor may be commonly used within the group. Even in this case,
Since the photosensors are commonly used, the number of photosensors can be reduced, the structure of the sheet detection unit can be simplified, and the cost can be reduced. As described above, when the number of levers is large, the sheet fed to the post-processing tray can be reliably detected.

In the above-described embodiment, the structure in which the operation detecting member is provided in conjunction with the movement of the lever is shown, but the movement of each lever is directly detected by one detecting means without using this operation detecting member. It is a matter of course that the configuration for detecting the error may be adopted. For example, a configuration may be employed in which light is emitted from one photosensor in the direction in which the levers are arranged, and when the light is blocked by the operation of the lever, the movement of the lever is directly detected.

Further, instead of the lever, a member that protrudes and retracts the post-processing tray 30 may be used. Therefore, the member operated by the seat is not limited to the lever.

[0093]

According to the sheet detecting device of the present invention, the operation in which a plurality of lever members are pressed by the sheet and operated is detected by a common detecting means. Therefore, the sheet is reliably detected with a simple structure. can do.

Since the sheet post-processing apparatus of the present invention is provided with the sheet detecting device capable of reliably detecting the sheet, the sheet can be processed even if the inclination angle of the sheet stacking means is made gentle. In addition, the thickness of the entire device can be reduced.

The image forming apparatus of the present invention has a sheet detecting device capable of reliably detecting a sheet, and includes a sheet post-processing device in which the thickness of the entire apparatus is reduced. , And can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view of a copying machine which is an image forming apparatus including a sheet post-processing apparatus having a sheet detecting apparatus according to an embodiment of the present invention in an apparatus main body.

FIG. 2 is a front sectional view of a sheet post-processing device having the sheet detection device of FIG. 1;

FIG. 3 is a plan view of a sheet post-processing apparatus having the sheet detection apparatus according to the embodiment of the present invention.

FIG. 4 is a plan view of a sheet detection unit which is a sheet detection device according to the embodiment of the present invention.

FIG. 5 is a state diagram when sheets are not stacked on a post-processing tray in the sheet detection unit of FIG. 4;

FIG. 6 is a state diagram when sheets are stacked on a post-processing tray in the sheet detection unit of FIG. 4;

FIG. 7 is a cross-sectional view of the sheet post-processing apparatus viewed from the direction of arrow B in FIG. 3, and is a state diagram immediately after a sheet is discharged to a post-processing tray in a normal post-processing operation of the sheet post-processing apparatus. is there.

8 is a diagram illustrating a state in which the sheet is abutted against a sheet rear end stopper by a return arm roller from the state of FIG. 7, and alignment in the sheet conveying direction is completed.

9 is a state diagram when the sheet bundle on the post-processing tray is discharged onto the stack tray from the state of FIG.

FIG. 10 is a cross-sectional view of the sheet post-processing apparatus viewed from the direction of arrow B in FIG. 3, and is an operation explanatory view of a sheet detection unit when a thin sheet is detected as in the second original drawing.

11 is a diagram illustrating a state where a sheet is discharged onto a post-processing tray from the state illustrated in FIG. 10;

FIG. 12 is a plan view of a sheet detection unit which is a sheet detection device according to another embodiment of the present invention.

13 is a state diagram when sheets are not stacked on a post-processing tray in the sheet detection unit of FIG. 12;

FIG. 14 is a state diagram when sheets are stacked on a post-processing tray in the sheet detection unit of FIG. 12;

FIG. 15 is a plan view of a sheet detection unit which is the sheet detection device according to the embodiment of the present invention.

FIG. 16 is a state diagram when sheets are not stacked on a post-processing tray in the sheet detection unit of FIG. 15;

FIG. 17 is a state diagram when sheets are stacked on a post-processing tray in the sheet detection unit of FIG. 15;

FIG. 18 is a cross-sectional view of a copying machine in which a sheet post-processing device having a conventional sheet detection device is provided in an apparatus main body.

19 is a cross-sectional view of the sheet post-processing apparatus of FIG.

[Explanation of symbols]

S, S1 Sheet A Point at which the sheet lands on the processing tray D Rotation direction of sheet detection levers 21, 71, 91 E Rotation direction of sensor flag F Rotation direction of sheet detection levers 22, 71, 91 G Sheet detection Rotation direction of lever 21 H Rotation direction of sheet detection lever 22 I Rotation direction of lever 23 X Rotation center axis of levers 21, 71, 91 Y Rotation center axis of levers 22, 72, 92 Z Sensor flag 23 1 Sheet post-processing device 9 Discharge roller pair 10 Stapler 20, 70, 90 Sheet detecting unit (sheet detecting device) 21, 22, 71, 72, 91, 92 Lever (sheet operating member) 21a, 22a, 71a, 92a Pressing surface 21b, 71b, 91b Tip 21c Hook 22b, 72b, 92b Detector 23 Sensor flag (detection Moving member) 23a interlocking arm portion 23b sensor light shielding portion 24, 74, 94 photosensor (detection means) 25, 75, 95 sheet detection sensor plate 26, 27, 76, 77, 96, 97 spring 30 post-processing tray (sheet stacking) Means) 31 sheet rear end stopper (sheet receiving means) 33 guide part (sheet guiding means) 40 sheet width aligning device 50 return arm roller (sheet conveying means) 60 sheet bundle discharge belt 72a interlocking arm part (detection operating member) 72c, Reference numeral 91c Sensor light blocking portion (detection operating member) 80 Stack tray 91a Arm portion (detection operating member) 100 Copy machine (image forming apparatus) 101 Printer section 102 Image reading section 103 Main body of copying machine (image forming apparatus) 105 Recirculating document Transport device (RDF) 112 Photoconductor drum (image forming means)

Claims (10)

[Claims] 1. A sheet detecting device, wherein the operation of a plurality of sheet operating members arranged in a sheet conveying direction and operated by being pressed by the sheet is detected by a single detecting means. 2. A detection operation member which operates when any one of the plurality of sheet operation members is pressed by the sheet and operates, wherein the detection means controls the operation of the detection operation member. The sheet detection device according to claim 1, wherein the detection is performed. 3. The sheet detection device according to claim 2, wherein the detection operation member is a member separate from the plurality of sheet operation members. 4. The detection operation member is provided on one of the plurality of sheet operation members, and the detection operation member is provided on one of the plurality of sheet operation members.
The sheet detecting device according to claim 2, wherein the one sheet operating member operates when the other sheet operating member is pressed by the sheet, in addition to the operation performed by being pressed by the sheet. 5. The sheet detecting device according to claim 1, wherein the sheet operating member is a lever that is rotated by being pressed by the sheet. 6. The sheet detecting device according to claim 1, wherein the detecting unit is a photo sensor. 7. A sheet detecting device according to claim 1, wherein the sheet is fed to the sheet loading device, and the sheet is fed to the sheet loading device. Sheet receiving means for receiving the sheet on the downstream side in the direction in which the sheet is fed, and sheet conveying means for abutting and conveying the sheet fed to the sheet stacking means against the sheet receiving means; Wherein the sheet operating member is arranged upstream in the direction in which the sheet is fed from the sheet receiving means. 8. A sheet detecting device according to claim 1, wherein the sheet is fed to the sheet stacking device, and the sheet is fed to the sheet stacking device. Sheet receiving means for receiving the sheet at the downstream side in the direction in which the sheet is fed; sheet guiding means disposed opposite to the sheet stacking means for guiding the downstream end of the sheet to the sheet receiving means; Sheet conveying means for abutting and conveying the sheet fed to the sheet receiving means, and wherein the plurality of sheet operating members of the sheet detecting device are fed with the sheet from the sheet receiving means. And at least one sheet actuating member is arranged at a position facing the sheet guiding means. Sheet post-processing apparatus according to claim. 9. An image comprising: an image forming means for forming an image on a sheet; and the sheet detecting device according to claim 1 for detecting the sheet. Forming equipment. 10. An image forming means for forming an image on a sheet, and the sheet post-processing device according to claim 7 for processing a sheet on which an image has been formed by said image forming means. Characteristic image forming apparatus.