JP2001240293A - Sheet loading device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an offset mechanism without mounting a jogger and an intermediate loading part, miniaturize a sheet loading device, and reduce the manufacturing cost. SOLUTION: This sheet loading device comprises a sheet loading tray 210 for loading sheet conveying means 204, 205 for conveying the sheets having images formed thereon to the sheet loading tray, and an aligning means for bringing at least one of front and rear edges in the sheet conveying direction of the sheets conveyed onto the sheet loading tray, into contact with a loading wall part for aligning the end faces of the loaded sheets, the aligning means is provided with plural loading wall parts 213, 214 mounted on the positions different from each other along the conveying direction, and the end faces of the sheets are brought into contact with the loading wall part 214 at an upstream side in the sheet moving direction when the predetermined number of sheets have been loaded on the sheet loading tray.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet stacking apparatus and an image forming apparatus, and is mounted or connected to an image forming apparatus such as a copying machine, a printer, a facsimile machine, etc., and discharges and stacks a sheet on which an image has been formed (printed). The present invention relates to a sheet stacking device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copier, a printer, a facsimile machine, etc., when a printed sheet output from an image forming section is discharged to a sheet stacking tray, it is sorted for each job. In addition, a so-called job offset mechanism that shifts the sheet stacking position for each job,
The image forming section was provided in a sheet discharge section after the image forming section. In general, the job offset mechanism is of a type in which a stacking position is shifted in a left-right direction (width direction) orthogonal to a sheet conveying (discharging) direction.

[0003]

Here, in order to offset the job in the left-right direction with respect to the sheet conveyance direction,
A mechanism for aligning the sheet bundle for each job and moving the sheet bundle left and right by a predetermined amount is required. As a means for this, a so-called intermediate stacking unit for temporarily stacking sheets is provided, and after stacking sheets for each job in this intermediate stacking unit, the sheet is aligned in one of the right and left directions while aligning the sheet side surface with a dedicated jogger. By moving and offsetting, then, by conveying and stacking the offset bundle of sheets to the sheet stacking tray,
Generally, a mechanism for offset-loading the stacking position on the sheet stacking tray to the left and right in the transport direction for each job has been common.

However, when such a job offset mechanism is used, an intermediate stacking section and a jogger for moving the sheet bundle in a horizontal position are required, and the apparatus becomes large and expensive. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet stacking apparatus capable of reducing the size of the apparatus as a whole and having a low manufacturing cost while having an offset mechanism, and an image forming apparatus having the sheet stacking apparatus. is there.

[0006]

The main components of the sheet stacking apparatus and the image forming apparatus of the present invention which have achieved the above-mentioned object are a sheet stacking tray on which sheets are stacked and a sheet stacking tray on which images are formed. Sheet conveying means for conveying the sheet to the sheet stacking tray, and aligning at least one of the front and rear ends of the sheet conveyed to the sheet stacking tray with the stacking wall to align the end face of the sheet to be stacked. Aligning means, the aligning means comprises a plurality of stacking walls arranged at two or more different positions along the transport direction, when a predetermined number of sheets are stacked on the sheet stacking tray, The end surface of the sheet is brought into contact with the loading wall on the upstream side in the sheet moving direction.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment described below, an image-formed sheet output from a laser beam printer or the like is received from a sheet discharge port, and 1000 sheets are received.
An example in which the present invention is applied to a sheet discharge and stacking device for stacking a large number of sheets from 3,000 to a so-called stacker will be described.

<First Embodiment> FIG. 11 is a schematic diagram showing the configuration of a sheet stacking apparatus and an image forming apparatus for explaining the overall configuration of a sheet stacking apparatus and an image forming apparatus to which the present invention is applied. It is. Here, a configuration example in which a stacker 200 as a sheet stacking device is detachably connected to a printer main body 100 as an image forming apparatus will be described. However, in the present invention, the printer main body 100 and the stacker 200 are integrated. It is also possible to apply to an image forming apparatus. Further, the image forming apparatus to which the stacker 200 is connected is not limited to a printer, but may be a copying machine, a facsimile machine, or a multifunction machine thereof.

The printer main body 100 is connected to a computer (not shown) and performs an image forming operation based on a print command output from the computer. As shown in FIG. 11, the printer main body 100 has an image forming unit including a process cartridge 106 for forming a toner image and a transfer roller 107 as an image transfer unit, which is disposed substantially at the center of the apparatus. Upper and lower two-stage sheet stacking cassettes 101 and 102 for stacking sheets to be supplied to the forming unit are arranged below the apparatus, and the sheets fed from any of the sheet stacking cassettes 101 and 102 are carried into the image forming unit. A registration roller unit 105 is provided in a stage preceding the image forming unit.

A fixing unit 108 for fixing the toner image on the sheet formed by the image forming unit and an image forming surface of the sheet on which the fixing process is performed by the fixing unit 108 are provided at the subsequent stage of the image forming unit. Face-down discharge roller pair 110 and face-down discharge tray 111 for performing a so-called face-down discharge with the image side down, and a face-up discharge roller pair 112 and a face for performing a so-called face-up discharge with the image forming surface on the upper side. An upper discharge opening 113 and a flapper 109 for switching the conveyance path of the sheet on which the fixing process has been performed are provided.

Further, the printer main body 100 is provided with a display unit and a printer control unit (not shown) at the upper part and inside of the apparatus main body, respectively. Here, the printer control unit controls the driving and operation of each unit described above, and the display unit displays the state of each unit described above. Further, the flapper 109 includes a sheet conveying path connected to the face-down discharge roller pair 110 and the face-up discharge roller pair 11.
2 is provided at a branch point with a sheet conveying path connected to 2,
It rotates based on a control signal from the printer control unit, and switches the conveyance path of the sheet on which the fixing process has been performed.

On the other hand, as shown in FIG. 11, the stacker 200 has an entrance guide section 201 for guiding and carrying an image-formed sheet output from the face-up discharge opening 113 of the printer body 100, and an entrance guide section. 201
An inlet roller pair 202 provided in a transport path connected to
The sheet conveyed by the pair of entrance rollers 202 has a reversing roller 203 and a reversing tray T for conveying in the reverse direction, and a substantially C-shaped cross section for reversing the upper surface of the sheet conveyed in the reverse direction by the reversing roller 203. Reverse guide part 2
03a, the discharge roller 204 and the discharge roller 205 disposed at the end of the reversing guide 203a, and the sheet conveyed by the discharge roller 204 and the discharge roller 205, which is disposed so as to be able to reciprocate vertically in the apparatus main body. And a sheet stacking tray 210. These units operate based on a control signal of a stacker control unit (not shown) provided in the main body of the stacker 200.

The printer control unit of the printer main body 100 and the stacker control unit of the stacker 200 are connected to each other via communication means (not shown).
The connection state between the printer 100 and the stacker 200 is constantly monitored by the respective control units. When the printer 100 and the stacker 200 are not connected, the fact is displayed on the display unit of the printer 100. Information to that effect is sent to the computer connected to the computer 100.

When the sheets stacked in the sheet stacking cassettes 101 and 102 of the printer body 100 are selectively separated and fed one by one by various rollers constituting a sheet feeding unit (not shown), a registration roller unit 105 is provided. Is carried into the image forming unit at a predetermined timing, and a desired toner image is formed on the upper surface of the sheet by the image forming unit. Then, the toner image is fixed on the sheet that has passed through the image forming unit by the fixing unit 108 at the subsequent stage.

The stacker 200 is connected to the printer main body 100, and a job of the printer main body 100 (hereinafter, referred to as a print job) is stored in the stacker 200.
In the case of an output instruction to the stacker 200, the flapper 109 operates to the face-up output side to convey the sheet to the stacker 200.

Face-up discharge unit 1 of printer 100
The sheet conveyed to the stacker 13 is sent to the pair of entrance rollers 202 and further to the reversing roller 203 via the entrance guide section 201 of the stacker 200, is reversed by the reversing roller 203 and the reversing tray T, and is discharged.
5, the sheet is discharged face-down onto the sheet stacking tray 210 and stacked.

Next, a first embodiment of a job offset mechanism in a stacker to which the present invention is applied will be described with reference to FIGS.
This will be described in detail with reference to FIG. The portions having the same functions as the portions described in FIG. 11 are denoted by the same reference numerals.

As shown in FIG. 1, the job offset mechanism of the first embodiment guides the conveyance of a sheet by a discharge roller 204 and a discharge roller 205 as sheet conveying means and a reversing roller 203 in FIG. , Roller pair 20
Sheet guide member 206 for supplying
207, a fixed wall 213 as a first sheet stacking wall located below the discharge roller 204, and a fixed wall 21
The sheet stacking tray 210 movably mounted in the vertical direction along the sheet 3 and the fixed wall portion 213 on the upstream side in the sheet moving direction (the downstream side in the sheet conveying direction by the discharge rollers 204 and the discharge rollers 205). An offset locking member 214 as a second sheet stacking wall portion movably arranged in a vertical direction.

The sheet guide members 206 and 207 are shown in FIG.
One of the reversing guide portions 203a is disposed at a position where the sheet is guided to a nip portion between the discharge roller 204 and the discharge roller 205. Here, the lower sheet guide member 207 is bent and folded at a position protruding from the base end side of the sheet stacking tray 210, and is bent downward at a predetermined position, so that the roller shaft of the discharge roller 204 and the offset. A storage space portion for storing the locking member 213 is formed, and the fixed wall portion 213 is continuously formed below the storage space portion.

The discharge roller 204 is disposed downstream of the offset locking member 214 in the sheet conveying direction.
The shaft portion is attached so as to rotate in the storage space of the lower sheet guide member 207, and is driven by driving means (not shown).

The discharge roller 205 is positioned above the discharge roller 204 so as to be rotatable about a support shaft 205a.
4 to be pressed against.

A plurality of offset locking members 214 are provided in the width direction of the sheet stacking tray 210, and slide with respect to a guide groove 207 a formed in the sheet guide member 207, so that the offset locking member 214 is fixed to the fixed wall portion 213. It is arranged to be able to move up and down substantially in parallel. Offset locking member 2
As shown in FIG. 1, the upper end 14 has a bent portion bent to the upstream side in the sheet conveying direction, and this bent portion is
Is supported from below by a lever 216 that can rotate around the center.

The lever 216 is urged clockwise in FIG. 1 by a spring 217 attached to the other end, and in a normal state (initial state), the offset locking member 214 is moved to the sheet guide member 207. By storing the offset locking member 214 in the storage space of FIG.
At the evacuation position shown in FIG. Further, a solenoid 218 is connected to the lever 216. When the solenoid 218 is turned on, the lever 216 is pulled down against the urging force of the spring 217, so that the offset locking member 214 is lowered.

As shown in FIG. 1, the main surface of the sheet stacking tray 210 is inclined such that the leading end side (the sheet conveying direction side) is located upward, and the sheet stacking tray 210 is conveyed and placed on the main surface. The sheet moves toward the base end (to the right in FIG. 1). The sheet stacking tray 210 is at the initial position shown in FIG. 1 when there is no sheet on the main surface,
As the stacking height of the sheets increases, the tray driving means (not shown) is controlled as follows so as to descend in the direction of arrow C in FIG.

Above the sheet stacking tray 210, a stacking height detecting lever 21 for detecting the stacking height of sheets is provided.
1 is rotatably disposed about the shaft portion 212. In the stacker of the embodiment, the sheet stacking tray 21
When there is no sheet above the stacking height 0, the stacking height detection lever 21
When the sheet 1 is brought into contact with the sheet stacking tray 210 by its own weight and the sheet is conveyed by the drive of the discharge roller 204, the sheet is pushed off the stacking height detection lever 211 and is conveyed and discharged onto the sheet stacking tray 210. .

In this stacker, when the height of the sheets stacked on the sheet stacking tray 210 increases, the rotation angle of the stacking height detecting lever 211 that comes into contact with the uppermost surface of the sheets becomes a predetermined angle, The ON / OFF of a sensor (not shown) is switched, and the driving of the tray driving unit of the sheet stacking tray 210 is controlled accordingly, whereby the sheet stacking tray 210 and the uppermost surface of the sheet are lowered.

When the sensor is switched on and off again due to a change in the rotation angle of the stacking height detection lever 211 accompanying the lowering of the uppermost surface of the sheet, the sheet stacking tray 210 is turned on. When the driving of the driving means is stopped, its lowering is stopped. With this control, the uppermost surface of the sheet on the sheet stacking tray 210 is held at a position within a certain range. Specifically, the uppermost surface of the sheet on the sheet stacking tray 210 is
When the offset locking member 214 is lowered by turning on 8, the lower end side of the offset locking member 214 is held at a position (see FIGS. 5 and 6) within a range in which the lower end of the offset locking member 214 can contact the uppermost surface of the sheet.

As shown in FIGS. 2 to 4, the sheet stacking tray 210 is provided at both ends in the width direction of the sheet stacking tray 210.
Sheet holding members 219 and 220 for locking the sheets stacked on the sheet 10 are arranged on the opposite sides.
These sheet pressing members 219 and 220 are formed of an elastomer resin as an elastic material, and are rotatably arranged around respective rotating shafts 221 and 222 as shown in FIG.

Then, the sheet pressing members 219, 220
As shown in FIG. 4B, the sheet loading tray 210 is elastically deformed by transmitting the rotational driving force of a drive motor (not shown) to the rotating shafts 221 and 222.
In the direction of pressing (directions of arrows A and b in FIG. 4B). The sheet holding members 219 and 220 are shown in FIG.
The rotation is stopped at a position (sheet holding position) shown by (1) and a position (standby position) shown by a solid line in FIG. 4 (b). The sheet holding members 219 and 220 hold both sides of the uppermost surface of the sheets stacked on the sheet stacking tray 210 with a predetermined pressure from the upper surface at the sheet holding position shown in FIG. Note that while the sheet stacking tray 210 can be moved in the vertical direction, each of the sheet pressing members 219 and 2
20 does not move in the vertical direction.

Next, the operation of each unit in the stacker having such a configuration when it is specified by a predetermined signal that offset stacking is performed for each print job will be described. First, the operation of each unit in the first job in the case where normal loading is performed will be described.

The sheet P, which is reversed by the reversing roller 203 in FIG. 11 and conveyed with the print surface down, is conveyed to the nip portion of the discharge roller 204 and the discharge roller 205 via the sheet guide members 206 and 207 in FIG. And discharge rollers 2
1 is conveyed to the left side in FIG. 1 by being driven to rotate counterclockwise in FIG. 1, and is discharged onto the sheet stacking tray 210 by pushing down the stacking height detection lever 211.

At this time, the sheet P is conveyed on the sheet stacking tray 210 by the inclination of the sheet stacking tray 210 until the rear end face in the conveying direction abuts against the fixed wall 213 as the first sheet stacking wall. Moves in the opposite direction. Hereinafter, the sheet P sequentially conveyed by the discharge roller 204 contacts the fixed wall portion 213,
While the respective end faces are aligned, the sheet stacking tray 21
It is loaded on 0.

During this operation, the sheet stacking tray 210
The stacking height of the upper sheet is constantly monitored by the stacker control unit via the detection lever 211 and the sensor, and when the uppermost surface of the sheet reaches a predetermined position, the tray is driven based on the control signal of the stacker control unit. When the unit is driven, the sheet stacking tray 210 is lowered to a predetermined position. During the operation of the first job without offset, the sheet pressing members 219, 220
Are stopped at standby positions indicated by solid lines in FIG.

When the first job is completed in this way, a signal for starting the offset operation is sent from the printer main body 100 to the stacker, so that the second job for performing the offset is started.

Specifically, in the stacker, the lever 216
As shown in FIG. 5, the solenoid 218, which is actuated by the actuator, pulls down the lever 216 against the urging force of the spring 217, so that the offset locking member 214, which is the second sheet stacking wall, descends. Then, the sheet comes into contact with the uppermost surface of the sheets already stacked on the sheet stacking tray 210 by the first job.

In this state, the sheet is conveyed to the sheet stacking tray 210 by the discharge roller 204 and the discharge roller 205,
After being discharged, the discharged sheet is placed in the sheet stacking tray 2.
10, the sheet stacking tray 210 is moved until the rear end face in the conveyance direction comes into contact with the offset locking member 214.
It moves upward in the direction opposite to the transport direction. Hereinafter, the sheets P sequentially conveyed by the discharge rollers 204 are stacked on the sheet stacking tray 210 with their respective end faces aligned by contacting the offset locking member 21. As a result, the sheet conveyed in the second job is in a state where the stacking position is offset in the conveyance direction with respect to the sheet conveyed in the first job.

Next, when the third job without offset is started, first, the locking members 219, 220
Rotates from the standby position indicated by the solid line in FIG. 4B around the rotation centers 221 and 222 to the sheet holding position in FIG. 4A, and presses the upper surface of the sheet that has been offset loaded earlier.

In the stacker, after this, the solenoid 21
8 is turned off, the lever 216 is rotated by the urging force of the spring 217, the offset locking member 214 is pulled up to the retracted position, and the sheet for the next job can be conveyed. At this time, the locking members 219, 22
No. 0 holds the sheet until the third job is completed (see FIG. 6).

By this operation, the offset locking member 21
4 is retracted upward and the third job is
When the sheets are stacked with their end faces aligned with the stacking wall section 213, which is the sheet stacking wall section, the sheet stacked offset by the second job moves toward the fixed wall section 213 and the end face shifts. Is prevented.

Further, in this stacker, at the time of the fourth job for offsetting, the offset locking member 2
After lowering 14, the locking members 219 and 220 rotate in the directions of arrows A and B in FIG. 4B, respectively. At this time, the locking members 219 and 220 made of an elastic elastomer rotate while bending as described above and stop at the position shown in FIG. 4A, and are placed on the sheet stacking tray 210 in the third job. The uppermost surface of the discharged and stacked sheets is pressed. Thereafter, by repeating the above operation, the sheet is moved in the transport direction (discharge direction) for each job for which the offset is specified.
(See FIGS. 5 and 6).

As described above, in the stacker according to the present embodiment, since the sheets are offset and stacked in the sheet conveying direction, the offset mechanism can be realized without providing the jogger and the intermediate stacking section, thereby making the apparatus compact and In addition, the manufacturing cost can be reduced.

<Second Embodiment> Next, FIGS.
A second embodiment of the present invention will be described with reference to FIG. The parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In the first embodiment, in order to align one end surface of the sheet, the sheet stacking tray is provided with an inclination, and the one end surface of the sheet discharged to the sheet stacking tray is used by utilizing the inclination. The first or second sheet stacking wall portion is aligned. On the other hand, in the second embodiment, as shown in FIG. 7, the sheet stacking tray is provided horizontally, and a return roller 254 shown in FIG. 8 is provided to align one end surface of the sheet P. Has become.

Specifically, in the second embodiment, the driving pulley 251 and the roller 250
Driven pulley 253 and roller 256;
1, 253 is provided.

The drive pulley 251 is disposed at the same position as the discharge roller 204 of the first embodiment (see FIG. 1).
The shaft portion is attached so as to rotate in the storage space of the lower sheet guide member 207, and is driven by driving means (not shown).

The driven pulley 253 is driven and rotated by the driving means in the counterclockwise direction in FIG.

The driven pulley 253 is
It is configured to be rotatable around one shaft portion, and is always rotated in accordance with the uppermost surface of the sheets P stacked on the sheet stacking tray 210 ′. Further, in this embodiment, a detection unit (not shown) for detecting the height of the uppermost surface of the stacked sheets is provided based on the rotation position of the shaft 253a, and the sheet is detected based on an output signal from the detection unit. The lifting and lowering of the stacking tray 210 'is controlled.

Further, as shown in FIG.
A pull-in roller 254 as a sheet returning means is fixed to the shaft portion 253a of the shaft portion 253a so as to rotate integrally with the driven pulley 253. The pull-in roller 254 is provided with a plurality of paddles 254a made of an elastic body so as to extend radially from the center of rotation on the entire main surface (peripheral surface). The pull-in roller 254 is for pulling the sheet conveyed to the sheet stacking tray 210 ′ toward the fixed wall portion 213 and the offset locking member 214 by each paddle 254 a.
As shown in FIG. 8, the paddle 254a has a configuration in which the tip end side protrudes downstream from the transport belt 255.

Rollers 250, 256 are arranged at positions above the pulleys 251, 253 via a conveyor belt 255. Among them, the roller 256 facing the driven pulley 253 is rotatably supported on the distal end side of a lever 252 rotatable around a support shaft 257 on the base end side. The roller 256 presses against the driven pulley 253 by the urging force of the urging spring 208 that urges the lever 252 downward, and urges the driven pulley 253 downward.
At this time, the paddle 254a of the pull-in roller 254 comes into contact with the uppermost surface of the sheets stacked on the sheet stacking tray 210 ', and the transport belt 255 does not come into contact.

At both ends in the width direction of the sheet stacking tray 210 ′, the above-mentioned sheet pressing members 219, 2 for locking the sheets stacked on the sheet stacking tray 210 ′.
20 are arranged on the opposite sides (see FIGS. 2 to 4). The sheet pressing members 219 and 220 press the uppermost surface of the sheets already loaded in the immediately preceding job so that the offset loaded sheets P do not shift due to the conveying force of the pull-in roller 254.

Hereinafter, the operation of the stacker according to the second embodiment will be described. The sheet P, which has been reversed by the reversing roller 203 shown in FIG.
55 and the roller 250, and the transfer belt 25
7 is conveyed onto the sheet stacking tray 210 'by being driven to rotate counterclockwise in FIG.

At this time, the end face of the sheet P on the rear side in the transport direction rides on the paddle 254a of the drawing roller 254, and as the drawing roller 254 rotates, the sheet P moves in the direction of the fixed wall portion 213 and the offset locking member 214. The end surface is moved until it comes into contact with the fixed wall portion 213 or the offset locking member 214.

Then, as the stacking height of the sheets P stacked on the sheet stacking tray 210 'increases, the driven pulley 253 rotates clockwise in FIG. The detection means is switched on and off, and based on the output signal, the sheet stacking tray 2
The driving of the stacker control unit is controlled so that 10 'is lowered by a predetermined amount.

The operation of each part at the time of offset,
The operation of the sheet holding members 219 and 220 is the same as that of the first embodiment, and the description is omitted.

As described above, in the second embodiment, the sheet stacking tray 21 on which the conveyed sheets are horizontally mounted is provided.
Since the offset stacking is possible while adopting the configuration using 0 ', when the sheets stacked on the sheet stacking tray 210' are taken out and moved to a desk or the like, a shift between the end faces of the sheets occurs. The sheet can be placed on a desk or the like with the end faces neatly aligned vertically, so that the sheet can be easily handled.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. Note that portions having the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the first and second embodiments, the second sheet stacking wall and its driving means are one (one set), and the sheet stacking position is two places. In the embodiment, as shown in FIGS. 9 and 10, the second sheet stacking wall portion has two (two sets) of the offset locking member 214 and the offset locking member 270, and the sheet stacking position is three. .

That is, in this embodiment, a guide groove portion 207b is additionally formed in the sheet guide member 207, based on the configuration of the above-described first embodiment, and an offset locking member is formed in the guide groove portion 207b. 27
As the 0 slides, the offset locking member 270 is arranged to be able to move up and down substantially parallel to the fixed wall portion 213.

The offset locking member 270 has the same shape as the above-described offset locking member 214 disposed at the preceding stage.
The structure of the driving means for vertically moving is also the same as in the case of the offset locking member 214 described above. Further, each operation of the stacker is the same as that of the first embodiment, and the description thereof is omitted.

As described above, in the third embodiment, the second
By providing a plurality of sheet stacking wall portions and increasing the offset position, for example, for each user or for each purpose of use,
The position of sheets to be stacked on the sheet stacking tray 210 is set in advance, and the present invention can be applied to a so-called mailbox stack in which sheets are stacked according to an output person or an output purpose.

In this embodiment, an example in which the present invention is applied to the configuration of the above-described first embodiment has been described. However, the present invention can be similarly applied to the configuration of the above-described second embodiment.

Although the number (the number of sets) of the second sheet stacking wall portions is two in this embodiment, it is needless to say that three or more sets may be used.

In each of the above-described embodiments, the second sheet stacking wall portion is configured to be vertically movable.
The second sheet stacking wall portion may be configured to be rotatable, for example, about the upper end side, and may be retracted by being pulled in the sheet conveying direction upstream by an actuator or the like.

[0064]

As described above, according to the present invention,
Since the offset stacking can be performed in the sheet conveying direction, the offset mechanism can be realized without providing the jogger and the intermediate stacking unit described above, and the size of the entire apparatus can be reduced, and the manufacturing cost can be reduced. .

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a stacker for describing a first embodiment of a job offset mechanism in a sheet stacking apparatus according to the present invention.

FIG. 2 is a perspective view for explaining a stacked state of sheets in the stacker according to the first embodiment, in which a normal stacked state of sheets is indicated by a dotted line, and a stacked state of sheets by offset is indicated by a solid line.

FIG. 3 is a plan view illustrating the stacked state of FIG. 2, in which the position of a sheet in a normal stacked state is indicated by a dotted line, and the position of a sheet in an offset stacked state is indicated by a solid line.

FIGS. 4A and 4B are side views illustrating the movement of a sheet pressing member, wherein FIG. 4A illustrates a state in which a stacked sheet is pressed, and FIG. The respective states in the case where the processing is performed are indicated by dotted lines.

FIG. 5 is a diagram illustrating a state where the offset locking member is lowered in the stacker according to the first embodiment.

FIG. 6 is a diagram illustrating a state in which the offset locking member is raised to the retracted position and is stored in the storage space of the sheet guide member in the stacker according to the first embodiment.

FIG. 7 is a side view of a main part of a stacker for explaining a second embodiment of the job offset mechanism in the sheet stacking apparatus of the present invention.

FIG. 8 is a main part extraction diagram illustrating a configuration of a pull-in roller according to a second embodiment.

FIG. 9 is a side view of a main part of a stacker for describing a third embodiment of the job offset mechanism in the sheet stacking apparatus according to the present invention, in a case where two offset locking members are provided in the sheet conveying direction. FIG.

FIG. 10 is a plan view illustrating a state in which sheets are stacked in a stacker according to a third embodiment.

FIG. 11 is a schematic diagram showing an overall configuration for explaining a sheet stacking apparatus and an image forming apparatus of the present invention.

[Explanation of symbols]

 P sheet 100 Printer body (image forming apparatus) 101, 102 Sheet stacking cassette 105 Registration roller unit 106 Process cartridge 107 Transfer roller 108 Fixer 109 Flapper 110 Face-down discharge roller pair 111 Face-down discharge tray 112 Face-up discharge roller pair 113 Face Up discharge opening section 200 Stacker (sheet stacking device) 201 Inlet guide section 202 Inlet roller pair 203 Reversing roller 203a Reversing guide section 204 Discharge roller (sheet conveying means) 205 Discharge roller (sheet conveying means) T Reversing tray 206, 207 Sheet Guide member 207a, 207b Guide groove 208 Energizing spring 210, 210 'Sheet stacking tray 211 Stacking height detecting lever (top surface detecting means) 212 Axis 213 Fixed wall portion (first sheet stacking wall portion) 214 Offset locking member (second sheet stacking wall portion) 215 Support shaft 216 Lever 217 Spring 218 Solenoid (drive means) 219,220 Sheet pressing member 221, 222 Rotation Shaft 250, 256 Roller 251 Drive pulley 252 Lever 253 Follower pulley 253a Shaft 254 Retraction roller (sheet return means) 254a Paddle 255 Transport belt (sheet transport means) 257 Support shaft

Continuation of the front page (72) Inventor Tsuyoshi Waratani Within Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo (72) Inventor Masayoshi Fukatsu 3- 30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. (72) Inventor Atsushi Ogata 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 3F054 AA01 AC02 AC03 AC05 BA01 BA04 BH03 BH07 CA11 CA23 CA40

Claims (13)

[Claims] A sheet stacking tray on which sheets are stacked, a sheet conveying means for conveying the sheet on which an image is formed to the sheet stacking tray, and a sheet conveyed to the sheet stacking tray with respect to a sheet conveying direction. Aligning means for aligning at least one of the front and rear ends with the stacking wall to align the end faces of the sheets to be stacked, wherein the aligning means are different from each other along the transport direction. A plurality of stacking walls arranged at the above positions, wherein when a predetermined number of sheets are stacked on the sheet stacking tray, the end face of the sheet is brought into contact with an upstream stacking wall in the sheet moving direction. A sheet stacking device. 2. The stacking wall section includes a first stacking wall section and a retractable second stacking wall section disposed upstream of the first stacking wall section in the sheet moving direction. The sheet stacking device according to claim 1, wherein 3. The sheet stacking apparatus according to claim 2, wherein the aligning unit includes a driving unit that drives the second stacking wall. 4. The plurality of second units arranged at two or more positions different from each other along a sheet moving direction.
3. The sheet stacking apparatus according to claim 2, further comprising a driving unit that separately drives each of the stacking wall and the second stacking wall. 5. The apparatus according to claim 1, wherein the first sheet stacking wall is fixed, and the sheet stacking tray is arranged to be vertically movable along the first sheet stacking wall. Item 5. The sheet stacking device according to any one of Items 2 to 4. 6. An apparatus according to claim 6, further comprising an uppermost surface detecting unit configured to detect a position of an uppermost surface of the sheet conveyed to the sheet stacking tray, wherein the sheet stacking tray detects the position of the sheet based on a detection result of the uppermost surface detecting unit. 6. The sheet stacking device according to claim 5, wherein the sheet stacking device is moved so as to keep the position of the uppermost surface constant. 7. A guide member for guiding sheet conveyance by the sheet conveying means, wherein the first sheet stacking wall portion is continuous with the guide member, and wherein the second stacking wall portion is provided with the guide member. 7. The sheet stacking device according to claim 1, wherein the sheet stacking device can be stored in a space formed in the member. 8. The apparatus according to claim 1, wherein the second loading wall moves up and down substantially in parallel with the first loading wall.
8. The sheet stacking apparatus according to any one of claims 1 to 7. 9. The sheet stacking apparatus according to claim 1, further comprising a sheet holding member for holding a sheet conveyed to the sheet stacking tray. 10. The sheet stacking tray according to claim 1, wherein the sheet stacking tray is inclined so that the placed sheet moves in a direction opposite to a conveying direction of the sheet conveying unit. 2. The sheet stacking device according to 1. 11. A sheet returning means for returning an uppermost sheet conveyed to the sheet stacking tray by the sheet conveying means in a direction opposite to a conveying direction to abut on the first or second stacking wall portion. 2. The method according to claim 1, wherein
11. The sheet stacking apparatus according to any one of claims 10 to 10. 12. The sheet stacking apparatus according to claim 11, wherein said sheet stacking tray stacks the sheets conveyed by said sheet conveying means substantially horizontally. 13. A sheet stacking device according to claim 1, comprising: an image forming unit for forming an image on a sheet; and a conveying unit for conveying the image-formed sheet to the sheet stacking device. An image forming apparatus characterized in that: