JP2004345748A - Sheet stacking device and image forming device provided with this sheet stacking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet extrusion mechanism, of a small and simple structure, for temporarily holding sheets in a supporting tray, of which the images are formed by an image forming device and for transferring the sheets to a stacking stacker after performing after-treatment such as stapling. <P>SOLUTION: A sheet extrusion member 217 engaging with a sheet rear end provided in the supporting tray 203 for temporarily holding storing the sheets, is arranged so as to make fore and aft reciprocating motions on the supporting tray 203. A normal and reversible drive means is provided so as to make reciprocating motions between the stand-by position where the sheet extrusion member is positioned on the upstream side relative to the sheet mounting position and the carrying-out position where the sheet extrusion member is positioned on the downstream side to the sheet mounting position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet stacking device in an image forming apparatus such as a printer, a copying machine, and a printing machine, and a sheet support for temporarily holding a sheet when performing post-processing such as stapling, punching, and stamping on an image-formed sheet. The present invention relates to a sheet stacking apparatus provided with a tray and an image forming apparatus using the same.
[0002]
[Prior art]
[Patent Document 1] JP-A-2002-60118
[Patent Document 2] JP-A-2002-179322
[0003]
2. Description of the Related Art Generally, a sheet stacking apparatus that sequentially stacks and stores sheets processed by an image forming apparatus or the like on a stacker is used by being installed in final processes of various printers, copying machines, facsimile machines, printing machines, and the like.
Sheets are nipped one by one with a pair of transport rollers and directly carried out to the stacker, and sheets that are temporarily placed on a support tray and then moved to the stacker by moving the rear end of the sheet with an extruding member and carried out to the stacker. Is done.
The present invention relates to the latter method, and relates to a sheet pushing mechanism for transferring sheets from a tray temporarily supporting the sheets to a stacker and sequentially stacking the sheets.
[0004]
Conventionally, such a sheet pushing mechanism stacks a predetermined number of sheets on a tray that temporarily supports the sheets, and pushes out this sheet bundle to a stacker side by pushing pieces protruding above the tray as seen in the above-mentioned document 1. Therefore, this extruded piece is provided with a long groove from the inflow side to the unloading side of the tray at the center of the tray so as to protrude above the tray from the back side (back side) of the tray. The extruded piece is moved from the rear end to the front end on the tray by driving and rotating the pulley of the endless belt.
Therefore, the extruded piece rotates around the endless belt provided on the back side of the tray integrally with the endless belt, and protrudes upward from the tray during the half rotation of the endless belt, and sinks behind the tray during the remaining half rotation. To repeat the turning motion.
[0005]
The structure shown in the above cited document 2 is similarly configured. However, in such a structure in which the protruding extruded piece turns around the endless belt, the space occupied by the extruded piece is large and sensors such as sensors are provided on the back of the tray. There is a disadvantage in that the components cannot be arranged and the momentum device becomes large.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-described problem that the apparatus is enlarged due to the rotation of the extruded piece around the endless belt, and simultaneously extrudes the trailing end of the sheet onto the stutter car, and the extruded piece passes the sheet accumulated on the stacker. Therefore, when the paper on the stacker is excessively stacked or curled, the paper is entangled, causing a failure of the apparatus or damage to the sheet.
The main object of the present invention is to solve the above-mentioned problems with a simple structure, and furthermore, it is possible to stack sheets in an orderly manner by pressing the sheets on the stacker with extruded pieces that have conveyed the sheets onto the stacker. That is the subject.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention solves the above-mentioned problem by reciprocating a sheet pushing member, which is engaged with a sheet rear end provided on a support tray for temporarily holding a sheet, back and forth on the support tray. It is based on the idea of solving.
[0008]
According to a first aspect of the present invention, there is provided a sheet discharging means provided on a sheet conveying path for sequentially discharging sheets, a support tray for temporarily holding at least a part of the sheets from the sheet discharging means, and a downstream of the support tray. A stacker provided on the side for loading and storing sheets from the support tray, a sheet pushing member provided on the support tray and engaging with an edge of a sheet loaded on the support tray, and the sheet pushing member A drive unit capable of reciprocating between a standby position located on the upstream side with respect to the sheet placement position on the support tray and a carry-out position located on the downstream side, and a reversible driving means,
This makes it possible to reduce the size of the entire apparatus without the sheet pushing member turning around the support tray.
[0009]
According to a second aspect of the present invention, in the configuration of the first aspect, the sheet pushing member is constituted by a pushing piece projecting upward from the support tray and engaging with a trailing edge of the sheet, and the driving means is provided between the standby position and the unloading position. And a forward / reverse motor that reciprocates the belt member.
[0010]
According to a third aspect of the present invention, in the configuration of the second aspect, the extruded piece is configured to press a sheet on the accumulation stacker at a carry-out position, whereby the sheet stored in the accumulation tray is extruded. The sheet is pressed by the member, and the stacked sheets do not collapse.
[0011]
According to a fourth aspect of the present invention, in the configuration of the first aspect, the driving unit is controlled such that a speed of returning the sheet pushing member from the unloading position to the standby position is faster than a speed of moving the sheet pushing member from the standby position to the unloading position. This makes it possible to shorten the processing time of sheet discharge.
[0012]
According to a fifth aspect of the present invention, there is provided a sheet discharging means provided on a sheet conveying path for sequentially discharging sheets, a support tray for temporarily holding at least a part of the sheets from the sheet discharging means, and a downstream of the support tray. A stacker provided on the side for loading and storing sheets from the support tray, a sheet pushing member provided on the support tray and engaging with an edge of a sheet loaded on the support tray, and the sheet pushing member Drive means for reciprocating between a standby position located upstream and a carry-out position located downstream with respect to the sheet placement position on the support tray, and stapling, punching, Post-processing means for performing post-processing such as stamping, so that sheets can be post-processed on a support tray and then stored in an accumulation stacker. It can become.
[0013]
According to a sixth aspect of the present invention, there is provided an image forming unit for forming an image on a sheet, a sheet discharging unit for carrying out the sheet from the image forming unit, and temporarily holding at least a part of the sheet from the sheet discharging unit. A support tray, a stacker provided downstream of the support tray for loading and storing sheets from the support tray, and engaging with an edge of a sheet provided on the support tray and stacked on the support tray Forward and reverse drive means for reciprocating the sheet pushing member between a standby position located upstream and a carry-out position located downstream with respect to the sheet placement position on the support tray. This makes it possible to continuously perform a series of operations from image formation to post-processing and stacking.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 2 is an overall view of an image forming apparatus embodying the present invention, and FIG. 1 is an explanatory view of a main part thereof.
[0015]
2, the image forming apparatus includes an image forming unit 100, a post-processing unit 200, an image reading unit 300, and a document feeding unit 350, and has a unit structure incorporated in an independent casing. By combining these units, they can be used for various purposes.
In the drawing, the post-processing unit 200 is installed above the image forming unit 100, and then the image reading unit 300 and the document feed unit 350 attached thereto are installed above the processing unit 200.
[0016]
In order to reduce the installation space of the apparatus, each unit is sequentially stacked to form an image forming apparatus.
First, the image forming unit 100 is provided with the following structure so as to be used as an output printer by being connected to a computer or to be used as a copying machine by being connected to an image reading unit 300 described later.
[0017]
In the casing 101, a paper feed cassette 110, a printing unit 140, a fixing unit 150, a transport path 130 for transporting the paper in this order, and a paper discharge path 160 are incorporated. Although not shown, the paper feed cassette 110 is incorporated in the casing 101 so as to be attached to and detached from the casing 101 so that predetermined sheets (sheets) can be stored therein. The paper feed cassette 110 is provided with a paper feed roller 120 at a position where the paper feed roller 120 is rotated in the counterclockwise direction in FIG. Claws are provided. Therefore, when the paper feed roller 120 is rotated, only the uppermost sheet is separated and fed to the transport path 130 side.
[0018]
The transport path 130 is provided with a transport roller 131 and a registration roller 132. Then, the sheet guided to the conveyance path 130 is sent to the registration roller pair 132 by the conveyance roller 131 and waits. A printing unit 140 is provided downstream of the registration roller 132. Various printing means are known, and for example, an ink jet printing method, a thermal transfer printing method, or an offset printing method can be adopted. The drawing shows a case where the electrostatic printing method is adopted. In the figure, reference numeral 141 denotes an electrostatic drum (photoreceptor), around which a laser beam transmitter for forming a latent image on the electrostatic drum, a developing device for attaching toner ink, and a charging device for transferring ink to paper are provided. Are located.
[0019]
Accordingly, a latent image is formed on the electrostatic drum by a laser transmitter in accordance with an image signal sent from a computer or the like, and toner ink is adhered on the latent image by a developing device, and waits at the position of the registration roller pair 132. The paper is fed out and the toner ink is sequentially transferred onto the paper. Reference numeral 150 denotes a heating unit which is composed of heating rollers pressed against each other by a fixing unit, and sends the toner ink on the sheet to the sheet discharging path 160 while fixing the toner ink.
[0020]
Discharge rollers 190 and 191 and a discharge stacker 192 are provided in a discharge port 161 at the end of the discharge path 160, and sheets are stacked on the discharge stacker 192 by the discharge rollers 190 and 191. I have. Therefore, the sheets (sheets) from the paper feed cassette 110 are subjected to predetermined printing by the printing unit 140 and fixed by the fixing unit 150, and then stacked and stored on the discharge stacker 192 from the discharge port 161. Become.
[0021]
Therefore, the paper discharge path 160 is provided with a connection path 162 that branches from the path toward the paper discharge port 161 and guides the paper to the post-processing unit 200 described later. The switching gate 170 directs the paper to the paper discharge port 161. Or the connection path 162 can be selected. That is, the switching gate 170 is formed by a solenoid so that the switching gate 170 rotates a predetermined angle in the counterclockwise direction from the state of FIG. 2 to block the path toward the paper discharge port 161 and at the same time feeds the sheet to the connection path 162 side. Driving means (not shown) is provided.
[0022]
"Post-processing unit"
The post-processing unit 200 includes a support tray 203 that temporarily holds sheets (sheets) sequentially discharged from the image forming unit 100, a paper binding staple that binds the sheets supported by the support tray by a predetermined number, and a sheet. Post-processing means 218 such as a punch for punching a predetermined position, a stamp for stamping a sheet, and an accumulation stacker 202 for storing the post-processed sheet are built in a casing 201.
Then, paper discharge rollers 205a and 205b are disposed at a paper discharge port 204 of a carry-in path 207 connected to the connection path 162 of the image forming unit 100 so as to nip the paper and carry it out to the right side in FIG. Is temporarily arranged, and the stackers 202 are arranged below the support tray 203 so as to form steps.
[0023]
Therefore, the sheet on which the image is formed by the image forming unit 100 is guided from the connection path 162 to the carry-in path 207 of the post-processing unit 200, is stored in the support tray 203 from the paper discharge port 204, and is subjected to the post-processing on the support tray 203 Are stored in the stacker 202. Details of the post-processing unit will be described later.
[0024]
"Image reading unit"
In the illustrated image forming apparatus, an image reading unit 300 and a document feeding unit 350 are mounted above a post-processing unit.
The image reading unit 300 includes a platen 302 for setting a document in a casing 301, a carriage 303 reciprocally movable along the platen 302, a light source 304, a mirror 305, a lens 306 mounted on the carriage 303, A conversion element 307 is incorporated.
The carriage 303 is held on a guide rail 310 fixed to the casing 301, and is connected to an endless belt 308 stretched between a pair of pulleys. The carriage 303 is configured to be movable in the left-right direction in FIG. 4 by a drive motor 309 connected to the pulley. The illustrated drive motor 309 is a pulse motor, and the endless belt 308 is a toothed timing belt. The position of the carriage 303 can be controlled. It has become. Note that the carriage 303 shown in FIG. 3 has the chain line position set to the home position.
[0025]
Accordingly, the document set on the platen 302 receives a reading start signal, and the carriage 303 moves from the home position to the right side in FIG. 4, and in the course of the movement, the light from the light source is reflected on the document surface and reaches the mirror 305. An image is formed on the photoelectric conversion element 307 via the lens 306, converted into an electric signal, and output. The photoelectric conversion element 307 shown in the drawing emits charges accumulated by reflected light from a document by a CCD (Charge Coupled Device) to the outside at a predetermined clock, and converts the electric signal as image data to the image forming unit 100 or an external computer. Will be sent to
[0026]
"Document feed unit"
A document feeding unit 350 is attached to the image reading unit 300 as an attachment. The document feed unit 350 includes a document feed tray 351, a sheet feed roller 352 that separates and feeds documents on the tray one by one, and a document fed from the sheet feed roller 352 to the image reading unit 300. The paper feed path 353 leads to the platen 302, and a paper discharge tray 354 that stores documents from the paper feed path 353.
[0027]
Reference numeral 355 denotes a backup plate provided at a (reading position) at a position facing the platen 302 in the paper feed path 353, and supports the document from the back side at the reading position to prevent image distortion. . In the drawing, reference numeral 356 denotes a pair of transport rollers provided in the paper feed path 353, and reference numeral 357 denotes a pair of discharge rollers connected to a drive motor.
Therefore, if a document is set on the paper feed tray 351 and a start signal is sent, the documents on this tray are sequentially sent to the reading position of the paper feed path 353.
Therefore, the carriage 303 of the image reading unit 300 is kept stationary at the position indicated by the solid line in FIG. 3 and sequentially reads the originals fed at the predetermined speed optically. The read original is stored on a discharge tray 354 via a discharge roller 357.
[0028]
"Structure of post-processing unit"
The post-processing unit 200 will be described in detail. A sheet on which an image is formed by the image forming unit 100 is guided from the connection path 162 of the unit 100 to the carry-in path 207 of the post-processing unit 200. A support tray 203 for temporarily holding sheets is disposed below the discharge port 204 of the carry-in path 207, and a stacker 202 is disposed further below the support tray 203 to support the sheet from the discharge port 204. It is configured to be transported to the tray 203 and then to the stacker 202.
[0029]
The illustrated support tray 203 and the stacking stacker 202 are configured as trays having a shape sufficient to place the sheets, and are disposed so as to be inclined such that the leading end side in the sheet discharging direction is higher, and regulate the end face of the sheet at the trailing end side. Stopper walls 203a and 202a are provided respectively.
Therefore, the sheets from the sheet discharge port 204 are first conveyed out along the support tray 203, are regulated by the stopper wall 203a, and are sequentially stacked. Next, after the sheet is subjected to post-processing, the sheet is carried out onto the stacking stacker 202, and is regulated and stacked by the stopper wall 202a.
[0030]
The shape of the support tray 203 may be such that the sheet unloading direction (the left-right direction in FIG. 1) is formed longer (longer) than the sheet length, but the illustrated one is made smaller (shorter). The size is reduced. Therefore, all sheets or at least the longest size sheet are supported in a bridge shape on the rear end side by the support tray 203 and on the front end side by the stacker 202.
[0031]
Therefore, the discharge port 204 is provided with a pair of discharge rollers 205a and 205b for nipping and discharging the sheet, and a discharge belt 206 for guiding the sheet from the discharge roller onto the support tray 203.
The paper discharge rollers 205a and 205b are formed of ordinary rubber or synthetic resin rollers, and are mounted at positions where the rotary shafts 210a and 210b mounted on the apparatus frame are pressed against each other. The discharge belt 206 is a rubber endless belt having projections formed on the surface thereof, which is a so-called caterpillar belt, and is stretched between the pair of pulleys 212 and 213. One pulley 212 is fixed to the rotating shaft 210b, and the other pulley 213 is supported by a bracket 214 rotatably attached to the rotating shaft 210b.
Accordingly, the discharge belt 206 is configured such that the pulley 213 can swing vertically in FIG. 1 around the pulley 212, and the pulley 213 moves up and down according to the loaded amount while contacting the loaded sheets on the support tray 203. Become.
[0032]
A drive motor, which will be described later, is connected to the rotation shaft 210b, and rotates the paper discharge roller 205b and the paper discharge belt 206 clockwise in FIG. The paper discharge roller 205a that comes into pressure contact with the paper discharge roller 205b is a driven roller.
In addition, a paddle 215 is provided at the position shown in FIG. 4 in the paper discharge port 204, and the paddle 215 is formed of a soft rubber plate-like piece and is fixed to a rotating shaft 216 attached to the apparatus frame. Therefore, the rotation of the rotation shaft 216 is controlled so as to move the sheet on the support tray 203 toward the stopper wall 203a, and details thereof will be described later.
[0033]
The support tray 203 is provided with an aligning member 219 for moving the stacked sheets in width so as to be movable in the front and back direction in FIG. 1 (a direction orthogonal to the sheet conveying direction). The alignment member 219 is mounted on the support tray 203 so as to reciprocate a plate-like member so as to engage with the side edge of the sheet and move the sheet in the direction perpendicular to the conveyance direction. The arranged racks are connected, and a pinion connected to a forward / reverse rotation motor is meshed with the rack to reciprocate.
[0034]
A post-processing unit 218 that performs post-processing on the stacked sheets is disposed on the support tray 203, and the illustrated one illustrates a stapling mechanism that binds a sheet bundle placed on the support tray 203. The stapling mechanism 218 incorporates a linearly connected needle (not shown), and a drive motor drives a former for bending the needle in a U-shape and a driver for inserting the needle in a U-shape into a sheet. The stapling is performed by using an anvil provided on the opposite side (back side) of the sheet by moving it well and driving the sheet bundle, and bending the tip of the needle provided on the opposite side (back side) of the sheet. In addition, as the post-processing means 218, a punch mechanism for punching a sheet or a stamp mechanism for stamping a sheet can be arranged on the support tray 203 instead of the stapling mechanism or together with the stapling mechanism. Are already known. Further, the support tray 203 is provided with a sheet pushing member 217 for carrying out the post-processed sheet to the collecting tray 202.
[0035]
The illustrated sheet pushing member 217 is provided movably on the supporting tray 203 by fitting the projecting sheet pushing pieces 217 into two long grooves formed in the supporting tray 203 in the left-right direction in FIG. The sheet push-out piece 217 has a shape having a sheet contact surface 217a that abuts on the trailing edge of the sheet bundle and pushes it out, and a sheet pressing surface 217b that is connected to the contact surface 217a and abuts on the upper surface of the sheet. It is configured. The sheet pushing member 217 is fixed to a transfer belt 218 provided on the back side of the support tray 203, and the transfer belt 218 is constituted by an endless belt stretched between pulleys 219 and 220 mounted on the back side of the support tray 203. ing. The driving of the transfer belt will be described later.
[0036]
A reference numeral 221a denotes a sensor lever provided in the sheet carry-in path 207 for detecting the leading end and the trailing end of the sheet, and a reference numeral 221 denotes a sensor for electrically detecting the operation of the sensor lever. The sheet stacker 202 is provided with a sheet presser 223 for pressing the uppermost sheet. The sheet presser 223 always presses the uppermost sheet in order to cause the sheet stacked on the stacker to partially rise due to curling or stapling, causing a collapse of the load and a malfunction of the full-state detection sensor.
[0037]
224 (FIG. 6) is a biasing spring for applying a pressing force to the sheet retainer 223, and biases the sheet retainer clockwise in FIG. When the sheet is sent from the support tray 202, the sheet retainer 223 needs to be retracted from the stacked sheets. For this reason, the sheet retainer 223 shown in the drawing rotatably supports the base end of the lever-shaped member on a shaft 225. Then, it swings between the pressed position in FIG. 6A and the retracted position in FIG. 6D. A cam follower pin 226 is provided integrally with the sheet retainer 223, and a cam 227 is engaged with the cam follower pin 226. The cam 227 is rotated against the spring 224 by the rotation of the cam 227 (counterclockwise in FIG. 6). The sheet presser 223 is moved from the pressed position to the retracted position. The driving of the cam 227 will be described later.
[0038]
The stacking stacker 202 is provided with a fullness detection lever 222 for detecting the uppermost position of the stacked sheets. In the illustrated stacking lever, an arm-shaped lever 222 is suspended from above the support tray 203 onto the stacking stacker 202. 228 are sensors for detecting the movement of the lever. The reason why the fullness detection lever 222 is suspended from above the support tray 203 onto the stacker 202 is that the sheet edge is detected as close to the center of the stacker as possible so that the edge of the sheet is stapled. This is because the load amount can be properly detected even when the swelling is caused by post-processing. Accordingly, when the fullness detection lever 222 is conveyed from the sheet discharge port 204 onto the support tray 203, it needs to be retracted from its transport path. The cam follower 230 is provided integrally with the base end portion.
[0039]
The cam follower 230 is engaged with a cam 231 fixed to a rotary shaft 216 to which the paddle 215 is mounted. The driving and control of the discharge roller 205, the discharge belt 212, the paddle 215, the sheet pushing member 217, the sheet pressing member 223, and the fullness detection lever 222 will be described. As shown in FIG. 5, the rotation of the drive motor M, which can be rotated forward and backward, transmits the rotation to a rotation shaft 210 to which a paper discharge roller 205b and a paper discharge belt 212 are attached via a transmission belt and gears. A one-way clutch 231 is built in between the rotating shaft 210 and the transmission gear attached to the rotating shaft 210, and transmits the rotation of the drive motor M that rotates forward and backward only in one direction indicated by an arrow.
[0040]
The drive motor M is adapted to be transmitted through a transmission gear train 232 to a rotating shaft 216 to which a paddle 215 is attached. A gear 234 attached to an intermediate shaft 236 shown in the figure and a gear 235 of the rotating shaft 216 meshing with the gear 234 are attached. Is intermittently transmitted. That is, the gear 235 is formed of a sector gear, and is partially disengaged from the gear 234 at a part of the outer periphery thereof.
[0041]
Further, a biasing spring 237 is bridged between the gear frame 235 and the apparatus frame so as to always rotate in one direction, and the rotation shaft 216 is fixed to the rotating shaft 216 so as to prevent the rotation by the biasing spring 237. A latch wheel 238 and a solenoid 239 that engages the wheel are provided. Then, when the solenoid 239 is energized and the actuator is separated from the latch wheel 238, the rotating shaft 216 is rotated by the urging spring 237, and the gear 235 meshes with the gear 234 connected to the drive motor M, and a rotational force is applied.
[0042]
In this state, when the power supply to the solenoid 239 is cut off, the actuator comes into contact with the outer periphery of the latch wheel and slides while the rotation shaft 216 makes one rotation, and the gear 234 and the gear 235 are disengaged. Locked. A cam 231 for retracting the paddle 214 and the fullness detection lever 222 is attached to the rotating shaft 216. Accordingly, the leading end of the sheet that has entered the carry-in path 207 with the drive motor M rotated is detected by the sensor 221 and is carried out of the discharge port 204 by the discharge rollers 205a and 205b and the discharge belt 206. After a predetermined time period based on the signal from the sensor 221, the solenoid 239 is energized to rotate the rotating shaft 216.
[0043]
Then, the cam 231 rotates in the time direction in FIG. 1 to rotate the cam follower 230 counterclockwise, and the fullness detection lever 222 integrally formed with the cam follower 230 also retreats above the support tray 203 around the rotation shaft 216. With the rotation of the rotation shaft 216, the paddle 214 attached thereto also rotates clockwise in FIG. 1 to feed the rear end of the sheet that has entered the support tray 203 to the stopper wall 203a side. On the other hand, a gear is transmitted to the transport motor M via an electromagnetic clutch 240 to a rotating shaft 241 to which a pulley 220 of the transfer belt 218 is attached.
[0044]
A sheet pushing member 217 is attached to the transfer belt 218. When the electromagnetic clutch 240 is engaged, the rotation of the drive motor M is transmitted to the rotating shaft 241 to move the sheet pushing member 217 to the right in FIG. When the rotation is reversed, the sheet pushing member 217 moves to the left side in FIG. A cam 227 of the sheet pressing member 223 is connected to the rotation shaft 241 via a gear train 242, and the cam 227 is rotated by the rotation of the rotation shaft 241 as shown in FIGS. 6A, 6B, 6C, and 6D. 3), the sheet pressing member 223 is moved from the sheet pressing position to the retracted position.
[0045]
At this stage, when the transport motor M is rotated in the reverse direction, the rotation of the rotating shaft 216 of the paddle 241 is not transmitted because the gears 234 and 237 are disengaged, and the discharge rollers 205a and 205b and the discharge belt 212 are also connected to the one-way clutch. 231 idles and rotation is not transmitted. On the other hand, a rotational force in the opposite direction is applied to the rotating shaft 217, and the transport belt 218 and the sheet pressing member 223 return in the order of FIGS. 6d, c, b, and a.
[0046]
The configuration of the sheet push-out member 217 will be described. The sheet push-out member 217 is formed by the projecting member having the sheet contact surface 217a and the sheet pressing surface 217b as described above, and is fixed to the transfer belt 218. Is configured to reciprocate, but the one shown in the drawing particularly has the following configuration.
[0047]
First, the sheet push-out member 217 is set to be stopped at a standby position (the position in FIG. 6A) slightly retreated from the stopper wall 203a of the support tray 203, and a limit sensor (not shown) for detecting the sheet push-out member 217 at this position. Z) is provided. In the illustrated embodiment, a stopper wall 203a is provided separately from the sheet pushing member 217 to regulate the trailing edge of the sheet on the supporting tray 203. However, the sheet pushing member 217 directly controls the trailing edge of the sheet on the supporting tray 203. May be regulated. The sheet pushing member 217 is connected to the electromagnetic clutch 240 in response to a processing end signal from the post-processing means 218 so that the driving force of the driving motor M is transmitted to the rotating shaft 241. With the rotation of the rotating shaft 241, the transfer belt 218 moves the sheet push-out member 217 from the state shown in FIG. 6A to the unloading position shown in FIG. 6D, and in this process, the sheets on the support tray 203 are stored on the stacker 202. You.
[0048]
The leading end of the sheet push-out member 217 is set to have a positional relationship of pressing the uppermost sheet on the stacker 202 at the unloading position. Therefore, when the sheet is stored on the stacker 202, the sheet pressing member 223 retracts to the state shown in FIG. 6D, but instead, the leading end of the sheet pushing member 217 presses the loaded sheet to cause a collapsed load state. Nothing.
Next, in the system configuration of the above-described image forming unit 100 and the post-processing unit 200 attached to the image forming unit 100, the present invention will be described with respect to an operation when a mode for performing post-processing such as stapling is set.
The sheet on which the image is formed by the printing unit 140 of the image forming unit 100 is guided to the paper discharge path 160 and is sequentially guided to the connection path 162 via the switching gate. At this time, at the same time as the mode is selected, the switching gate 170 is positioned to guide the sheet to the connection path 162 side.
[0049]
Then, the sheet from the connection path 162 reaches the carry-in path 207 of the post-processing unit 200 and is conveyed to the sheet discharge port 204.
In this process, the leading edge of the sheet operates the sensor lever 221a and the sensor 221 detects this, thereby detecting the arrival timing of the leading edge of the sheet and controlling the subsequent operation.
At this time, the above-described drive motor M is controlled to rotate the discharge roller 205b and the discharge belt 206 in the sheet discharge direction by a timing signal from the image forming unit 100.
The sheet is transported to the right in FIG. 1 with the rotation of the paper ejection roller 205 b and the paper ejection belt 206, and the leading end moves along the support tray 203. When the sensor lever 221b detects the rear end (passing) of the sheet, the solenoid 239 is actuated a predetermined time after the timing, the engagement of the rotation shaft 216 with the latch wheel 238 is released, and the rotation shaft 216 is attached. The spring 237 rotates by a predetermined amount. Then, the gear 235 attached to the rotating shaft 216 meshes with the gear 234 connected to the driving motor M, and the rotation of the driving motor M is transmitted to the rotating shaft 216, and the paddle 215 attached thereto rotates clockwise in FIG. I do. The leading end of the paddle 215 contacts the sheet on the support tray 203 and moves the sheet to the left in FIG. 1, but the timing is such that the trailing end of the sheet comes into contact with the sheet after the sheet is completely discharged from the discharge belt 206 onto the support tray 203. The operation timing of the solenoid 239 is set.
[0050]
At the same time as the rotation of the rotation shaft 216, the cam 231 attached to the rotation shaft 216 engages with the cam follower 230 to swing the fullness detection lever 222 in the counterclockwise direction in FIG. Before entering and colliding with the fullness detection lever 222, the lever retracts upward from above the support tray 203. That is, the cam 231 of the rotating shaft 216 retracts the detection lever 222 above the support tray 203 before the sheet front reaches the full detection lever 222 from the timing when the sensor lever 221a detects the front end of the sheet. Is activated. Then, the paddle 215 of the rotating shaft 216 comes into contact with the sheet on the tray 203 after the rear end of the largest sheet to be used is carried out onto the support tray 203, and moves the sheet in the left direction in FIG. In a relationship. The trailing edge of the sheet moved by the paddle 215 enters between the paper discharge belt 206 and the support tray 203, and stops by hitting the stopper wall 203 by the rotation of the belt 206. When the sheets from the sheet discharge port 204 are stacked on the support stacker 203 in this manner, the alignment member 206 moves a predetermined amount in the front and back direction in FIG. 1 (a direction orthogonal to the sheet conveyance direction) to align the sheets, and sequentially. The sheet is stacked on the support tray 203 by repeating such an operation. When the stacking of the predetermined sheets is completed, it is determined from the end signal from the image forming unit 100 or the fact that the next sheet does not reach the sensor lever 221a for a predetermined time or more, and the post-processing means 250 outputs a signal indicating the end of the processing or a predetermined end of the processing After the time, the electromagnetic clutch 240 connected to the drive motor M is operated to transmit the rotation of the drive motor M to the rotating shaft 241. Then, by the rotation of the pulley 219 attached to the rotating shaft 241, the transfer belt 218 rotates clockwise in FIG. 1, and the sheet pushing member 217 moves from the standby position in FIG.
[0051]
The post-processed sheet on the support tray 203 moves so as to be gradually extruded toward the stacker 202 as the sheet pushing member 217 moves. At this time, the cam 227 connected to the rotating shaft 241 by the gear train 242 engages with the cam follower pin 226 to swing the sheet pressing member 223 counterclockwise in FIG. 1 around the shaft 225 and the sheet pressing member 223 is integrated. Withdraw from the stacker 202.
[0052]
The sheet pushing member 217 pushes out the sheet on the support tray 203 onto the stacking stacker 202 before and after the sheet holding member 223 is retracted from the stacker 202, and the tip of the sheet pushing member 217 is stored in the stacker 202. The uppermost surface of the sheet is pressed downward.
[0053]
This operation will be described with reference to FIGS. 6A, 6B, 6C, and 6D. When the sheet pushing member 217 located at the standby position is in the state shown in FIG. 6A, the electromagnetic clutch 240 is actuated and the rotating shaft 241 is rotated. When rotated, it moves to the position shown in FIG.
[0054]
In the state shown in FIG. 7B, the cam 227 engages with the cam follower pin 226 to retreat the sheet pressing member 223 above the stacker 202. Further, with the rotation of the rotation shaft 241, the sheet pressing member 223 retracts to a position protruding above the support tray 203 in FIGS. 6C and 6D, and curves the sheet to be discharged in a direction orthogonal to the discharge direction. The conveyance force of the sheet push-out member 217 is transmitted to the sheet by the bending of the sheet in the conveyance orthogonal direction, and the sheet is vigorously discharged to the stacker 202 side.
[0055]
When the sheet pushing member 217 is located at the carry-out position in FIG. 6A, the leading end of the pushing member 217 presses the sheet on the stacker 202 downward instead of the sheet pressing member 223 to hold the stacked sheets. The extruding member 217 is provided with a limit switch at a standby position. When the control pulse of the drive motor M reaches a predetermined number of pulses with the movement from this position, the drive motor M is rotated in a reverse direction. A control signal is issued and the drive motor rotates in reverse. By the reverse rotation of the drive motor M, the sheet pressing member 223 moves (returns) in the direction of pressing the sheet on the stacking stacker 202 in the order of (d), (c), and (b) of FIG.
[0056]
At the same time, the sheet pushing member 217 returns along the support tray 203 in the order of FIGS. When the sheet pushing member 217 returns to the standby position shown in FIG. 6A, the limit switch detects this, the drive motor M is stopped by the signal, the electromagnetic clutch 240 is disconnected, and the initial state is set. Therefore, the same operation is repeated while waiting for the discharge of the sheet from the next image forming unit 100. In this process, the sheet push-out member 217 reciprocates between the standby position and the carry-out position on the support tray 203, so that the space occupied by the movement locus thereof is significantly smaller than that of a conventional endless belt that rotates around the endless belt.
[0057]
【The invention's effect】
As described above, the present invention has a configuration in which the sheet pushing member on the support tray reciprocates in the forward and reverse directions between the standby position and the carry-out position. The movement locus of the pushing member is also reduced in space, the driving mechanism is simplified, and the device can be downsized. Further, there is no possibility that the sheet loaded on the stacker is rolled into the apparatus by the sheet pushing member.
Further, according to the present invention, by setting the carry-out position of the sheet push-out member to a position for pressing the uppermost sheet on the stacking stacker, it is possible to orderly stack the sheets on the stacking stacker.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a main part showing an example of an embodiment of a sheet stacking apparatus according to the present invention.
FIG. 2 is an overall explanatory diagram showing an embodiment of an image forming apparatus according to the present invention.
FIG. 3 is an explanatory diagram showing a main part of an embodiment of the image forming apparatus according to the present invention.
FIG. 4 is a perspective view showing a driving mechanism of the sheet stacking apparatus according to the present invention.
FIG. 5 is a conceptual diagram showing a transmission system of the drive mechanism shown in FIG.
FIGS. 6A and 6B are explanatory diagrams of an operation state of the sheet pushing means shown in FIG. 1, wherein FIG. 6A shows a state of a standby position, FIG. 6B shows a state of being moved from the standby position, and FIG. The state of the carry-out position for carrying out the sheet to the stacking stacker is shown, and FIG. 4D shows the state of pressing and holding the sheet on the sheet stacking stacker.
[Explanation of symbols]
100 Image forming unit
110 paper cassette
130 transport route
140 printing means
150 fixing means
160 paper ejection path
200 Post-processing unit
202 Stacker
203 support tray
205a Discharge roller
205b Discharge roller
206 paper ejection belt
215 paddle
217 Sheet extrusion member
217a Sheet contact surface
217b Sheet holding surface
218 Post-processing means
219 Alignment member
221 Sensor lever motion detection sensor
222 Full detection lever
M drive motor
223 Sheet presser
300 image reading unit
302 Platen
303 carriage
307 photoelectric conversion element
350 Document feed unit
351 paper tray
354 output tray

Claims (6)

Sheet discharging means provided on a sheet conveyance path for sequentially discharging the sheet,
A support tray for temporarily holding at least a part of the sheet from the sheet discharging means,
An accumulation stacker provided downstream of the support tray for loading and storing sheets from the support tray;
A sheet pushing member provided on the support tray and engaged with an edge of a sheet stacked on the support tray;
A sheet stacking device having a reversible drive means for reciprocating the sheet pushing member between a standby position located upstream and a discharge position located downstream with respect to a sheet placement position on the support tray; apparatus. The sheet pushing member is constituted by a pushing piece projecting upward from the support tray and engaging with a sheet trailing edge,
2. The sheet stacking apparatus according to claim 1, wherein said driving means is constituted by a belt member bridged between said standby position and said carry-out position, and a forward / reverse motor for reciprocating said belt member. 3. The sheet stacking device according to claim 2, wherein the extruded piece is configured to press a sheet on the stacker at the unloading position. 2. The sheet stacking apparatus according to claim 1, wherein the driving unit is controlled such that a speed of returning the sheet pushing member from the unloading position to the standby position is faster than a speed of moving the sheet pushing member from the standby position to the unloading position. Sheet discharging means provided on a sheet conveyance path for sequentially discharging the sheet,
A support tray for temporarily holding at least a part of the sheet from the sheet discharging means,
An accumulation stacker provided downstream of the support tray for loading and storing sheets from the support tray;
A sheet pushing member provided on the support tray and engaged with an edge of a sheet stacked on the support tray;
Forward / reverse drive means for reciprocating the sheet pushing member between a standby position located upstream and a carry-out position located downstream with respect to a sheet placement position on the support tray,
A sheet post-processing apparatus comprising: a post-processing means provided on the support tray for performing post-processing such as stapling, punching, and stamping on a sheet. Image forming means for forming an image on a sheet,
Sheet discharging means for carrying out a sheet from the image forming means;
A support tray for temporarily holding at least a part of the sheet from the sheet discharging means,
An accumulation stacker provided downstream of the support tray for loading and storing sheets from the support tray;
A sheet pushing member provided on the support tray and engaged with an edge of a sheet stacked on the support tray;
An image forming apparatus having a reversible drive means for reciprocating the sheet pushing member between a standby position located upstream and a carry-out position located downstream with respect to a sheet placement position on the support tray; apparatus.

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