JP2004352406A - Sheet stacking device, and sheet post-processing device provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet stacking device in which sheets stacked on a stacker can be pushed with correct strength, so that paper surface level can be detected, and in which advance of the sheet is not prohibited, but a curled sheet or a bundle of stapled sheets can be contained in order even when a detection lever is faced to a desired position of the sheet, so that its paper surface level can be correctly detected. <P>SOLUTION: A sheet height detecting lever 222 to detect the sheet stacked on a discharged paper stacker 202 is composed to be capable of oscillating between a retraction position above a moving track of the sheet from a carrier guide 203 to carry the sheet to the discharged paper stacker and a detection position where it is applied to the discharged paper stacker. To the detecting lever 222, an actuation means 227 is connected to hold the detecting lever at the retraction position when the sheet is discharged. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet stacking apparatus for sequentially stacking and storing sheets discharged from an image forming apparatus such as a copying machine, a printer, and a facsimile, and a post-processing apparatus that performs post-processing such as sheet punching, stamping, and stapling using the sheet stacking apparatus. About.
[0002]
[Prior art]
[Patent Document] US6412774B1]
In general, this type of apparatus is known as a stack apparatus that receives sheets on which images are formed from image forming apparatuses such as a copying machine, a printer, a printing machine, and a facsimile, and stacks the sheets one above the other.
A tray is of a fixed type, in which sheets are stacked on a fixed tray, and a tray movable type, in which sheets are stacked on a vertically moving tray and the tray is gradually lowered in accordance with the amount of movement. Regardless of the tray fixed type or the tray movable type, the sheet height (stacking amount) on the tray is detected, the apparatus is stopped as full (allowable maximum stacking amount), and the tray is lowered gradually or used. Various controls are performed such as detecting that a user has removed a sheet from the tray.
As a conventional method for detecting the height of the sheet on the stacker, a detection lever is hung from above the stacker, the base end of the detection lever is rotatably supported, and the tip of the lever is brought into contact with the uppermost sheet. 2. Description of the Related Art A structure in which a sensor such as a photosensor microswitch is disposed at a base end portion of a sensor is widely known.
[0003]
However, in such a structure, when the sheet enters the stacker, the lever must be pushed up, and there is a problem that a thin sheet or a curled sheet is curved and cannot be correctly stacked, and conversely, the detection lever moves very lightly ( It is well known that the structure must be easy to swing.
On the other hand, sheets that have been stapled in a bundle or processed such as punching or stamping before the sheet is carried into the stacker are severely curled. I have. For this reason, it is necessary to detect the paper surface while pressing the paper surface to some extent while correcting the swelling.
Therefore, in order to solve such a malfunction due to such curling or partial bulging, in the above-mentioned patent document, an arm-shaped rotating lever is projected from the upper end of the side wall of the stacker at a position where the approach path to the sheet stacker cannot be prevented. The lever is retracted by driving a solenoid or the like at the timing when the sheet enters the tip of the lever (detection unit).
[0004]
[Problems to be solved by the invention]
However, in such a conventional structure in which the detection lever is swung in a limited space (space) between the sheet entrance path and the uppermost sheet, when a curled sheet is carried in, the detection sheet gets on the lever. May be stacked on top of it, which may lead to equipment failure. In particular, in a device for storing a stapled sheet bundle, there is a disadvantage that the climbing phenomenon frequently occurs when the stapling needle hits the detection position of the detection lever.
According to the present invention, a sheet stacked on a stacker can be pressed with an appropriate strength to detect a paper surface level, and even if a detection lever is placed at an arbitrary position on the sheet, the sheet is prevented from entering. A main object of the present invention is to provide a sheet stacking apparatus capable of neatly storing a curled sheet or a stapled sheet bundle without any trouble and correctly detecting the paper surface level. Further, in the present invention, a sheet post-processing means is provided on the sheet stacking section (sheet stacker) before obtaining the sheet, and the sheet level detecting mechanism of the stacking section does not affect the sheet operation at the time of post-processing. The task is to provide a processing device.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention comprises a sheet height detecting lever for detecting a stacked sheet on a discharge stacker, which is configured to be vertically movable past a movement locus of a sheet carried into the discharge stacker. It is based on the knowledge that the height of the central portion of the upper stacking sheet is detected to eliminate erroneous detection due to bulging of a sheet corner such as a stapler and failure due to riding on the detection lever. In this case, at the time of sheet inflow (conveyance), the detection lever is held at a position retracted from the sheet movement trajectory so as not to hinder sheet conveyance.
[0006]
In other words, the invention according to claim 1 includes a transport guide for transporting a sheet, a paper discharging means provided on the transport guide for sequentially discharging the sheet, a stacker provided with a step below the paper discharging means, and A sheet height lever that is in contact with the top of the sheet discharge stacker, and a detection sensor that detects the position of the detection lever; and the detection lever is moved upward along a path of movement of the sheet from the sheet discharge means to the sheet discharge stacker. It is configured so as to be swingable between a retracted position and a detection position where it comes into contact with a discharge stacker below, and an operation means for holding the detection lever at the retracted position when discharging a sheet is connected to the detection lever. With this, the sheet height detection lever moves and retracts between the path (trajectory) of the sheet conveyed to the conventional sheet discharge stacker and the uppermost sheet from between the stacked uppermost sheets. Posture and at the optimum position of the uppermost sheet on the sheet discharge stacker becomes possible to detect the height (level) compared to the structure of advancing and retreating between, and thus achieving the above-mentioned problem.
[0007]
According to a second aspect of the present invention, in the configuration of the first aspect, the operating means of the detection lever moves from the upper retreat position to the discharge stacker and moves from the lower discharge stacker to the retreat position by its own weight. With this configuration, the operation means of the detection lever is moved to the retracted position when the sheet is carried into the discharge stacker by a simple structure such as a cam, and the position of the operation lever is maintained until the sheet is carried in. Will be held.
[0008]
According to a third aspect of the present invention, in the configuration of the second aspect, the driving source of the operating unit is configured in common with the driving source of the paper discharging unit, and the cam unit regulates operation timing between the operating unit and the driving source. With this configuration, there is no need to provide a special drive source with a simple configuration from the drive source (drive motor) of the sheet discharge unit that carries the sheet into the sheet discharge stacker with a simple configuration.
[0009]
According to a fourth aspect of the present invention, in the configuration of the first aspect, the transport guide is configured in a tray shape on which a sheet is temporarily placed, and post-processing means such as a sheet punching stapler binding placed on the transport guide. With this configuration, sheets are temporarily stacked on a transport guide prepared on the upstream side of the discharge stacker, post-processing is performed on the stacked sheets, and the post-processed sheet is discharged onto the discharge stacker. It is possible to accurately detect the height of the sheet bundle stored in the printer, and to perform processing such as fullness accurately.
[0010]
According to a fifth aspect of the present invention, there is provided a sheet conveying means for sequentially conveying a sheet, a tray-shaped conveying guide for temporarily placing the sheet from the sheet conveying means, and a discharging guide provided on the conveying guide for discharging the sheet. A paper unit, a discharge stacker arranged with a step below the discharge unit, a sheet height detection lever in contact with the uppermost sheet of the discharge stacker, and a detection sensor for detecting the position of the detection lever. Wherein the detection lever is configured to be movable between a retracted position provided above a movement trajectory of the sheet from the sheet conveying means to the conveyance guide and a detection position in contact with the uppermost sheet of the discharge stacker, The detecting lever is connected to an operating means for holding the detecting lever at the retracted position when the sheet is transferred from the sheet conveying means to the conveying guide. It is possible to achieve the challenges of the predicate.
[0011]
According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the tray-shaped transport guide is provided with post-processing means such as perforating a sheet and stapling the sheet. Post-processing such as stapling can be performed on the placed sheet.
[0012]
According to a seventh aspect of the present invention, there is provided a sheet discharging means for sequentially discharging sheets, a tray-like transport guide for temporarily holding the sheets from the sheet discharging means, and a post-processing for performing post-processing on the sheets on the transport guide. Means, a sheet discharging means for conveying the sheet from the conveying guide to the sheet discharging stacker, a sheet height detecting lever in contact with the uppermost sheet on the sheet discharging stacker, and a sensor means for detecting the detecting lever. ,
The detection lever is moved from an upper retreat position to a lower discharge stacker through a sheet movement path from the sheet discharging means to the conveyance guide and a sheet movement path from the discharge guide to the discharge stacker. An actuating means configured to swing freely between a contact position and a detection lever, wherein the detection lever holds the detection lever at the retracted position when the sheet is discharged from the sheet discharging means to the discharge stacker; In the process of stacking the sheets conveyed from the image forming apparatus and the like on the discharge stacker after performing post-processing such as stapling, the stacking amount of the stacked sheets on the discharge stacker is reduced. It is possible to accurately detect.
[0013]
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.
[0014]
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.
[0015]
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.
[0016]
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.
[0017]
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.
[0018]
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.
[0019]
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.
[0020]
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.
[0021]
"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.
[0022]
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.
[0023]
"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.
[0024]
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
[0025]
"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.
[0026]
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.
[0027]
"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.
[0028]
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.
[0029]
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.
[0030]
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.
[0031]
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.
[0032]
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). (See FIG. 3) 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 a direction perpendicular to the conveyance direction. A rack arranged on the back side of the motor 203 is connected, and a pinion connected to a forward / reverse rotation motor is engaged with the rack to reciprocate.
[0033]
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.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
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.
[0040]
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.
[0041]
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.
[0042]
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.
[0043]
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 rotating shaft 241 via a gear train 242. The cam 227 moves the sheet pressing member 223 from the sheet pressing position to the retracted position with the rotation of the rotating shaft 241. It is made to let.
[0044]
At this stage, when the transport motor M is rotated in the reverse direction, the rotation of the rotating shaft 216 of the paddle 215 is not transmitted because the gears 234 and 237 are disengaged, and the paper discharge rollers 205a and 205b and the paper discharge belt 206 are also one-way clutches. 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, so that the transfer belt 218 and the sheet pressing member 223 return to the retracted position.
[0045]
An embodiment in which the present invention is applied to the above-described post-processing unit 200 will be described below. The paper discharge stacker 202 is constituted by a tray on which ordinary sheets are stacked, and is attached to a frame of the post-processing unit 200. The discharge stacker 202 is provided with a conveyance guide and a discharge means for discharging a sheet along the conveyance guide at a position where a step corresponding to the maximum stacking amount is formed. The illustrated one comprises a conveyance guide and a support tray 203 for temporarily holding a sheet, and the sheet discharging means is constituted by the sheet pushing member 217.
[0046]
In the present invention, the transport guide may be constituted by a guide for guiding the sequentially transported sheets without temporarily holding the sheets, and the sheet discharging means is configured to transport the sheets by nipping the sheets with a normal roller or belt. The configuration may be as follows.
[0047]
In the drawing, a carry-in path 207 and a paper discharge port 204 are prepared with a step therebetween on the upstream side of the support tray 203 constituting the conveyance guide, and the paper discharge port 204 has the above-described paper discharge roller 205 and paper discharge belt. A sheet carrying means 206 is provided.
That is, the sheets sequentially sent from the image forming unit 100 are transferred from the sheet discharge port 204 of the path 207 to the transport guide (the support tray 203) by sheet discharge means (the discharge roller 205 and the discharge belt 206). Then, the sheet is conveyed out onto the discharge stacker 202 by a discharge means (the sheet pushing member 217) along the discharge guide.
In such a configuration, the fullness detection lever 222 that contacts the uppermost sheet on the discharge stacker 202 and detects the stacking amount of the sheets moves along the movement trajectory of the sheet from the transport guide (203) to the discharge stacker 202 as shown in FIG. The paper stacker 202 hangs over the paper discharge stacker 202 so as to pass by. At the same time, the fullness detecting lever 222 hangs from a position where the sheet transfer trajectory from the paper discharge port 204 to the transport guide 203 also passes, and is moved to a shaft 229 provided above the paper discharge stacker 202 as shown in FIG. The base end of the lever member is pivotally supported.
[0048]
A plate-shaped actuator 228a and a cam follower 230 are formed integrally with the fullness detection lever 222, and the detection lever 222, the actuator 228a, and the cam follower 230 are configured to rotate integrally about a shaft 229. I have.
The three members are urged by their own weight so that the detection lever 222 always contacts the sheet discharge stacker 202. The actuator 228a is engaged when the detection sensor 228 and the fullness detection lever 222 are at the predetermined maximum loading position, and detects the state.
[0049]
A cam follower 230 integrated with the full-state detection lever 222 is configured to engage with a cam 231 mounted on a rotation shaft 216 of the paddle 215, and the detection movement of the cam 231 causes the detection lever 222 to move above the discharge stacker 202. It is designed to be evacuated. That is, the rotating shaft 216 to which the cam 231 is attached is connected to the drive motor M via the gears 235, 234, the intermediate shaft 236, and the transmission gear train 232, which are composed of sector gears. At the same time, a latch wheel 238 and a biasing spring 237 are provided on the rotating shaft 216, and a solenoid 239 is engaged with the latch wheel 238. The latch wheel 238 stops the rotating shaft 216 in a state of being engaged with the actuator of the solenoid 239. At this time, the sector gear 235 and the gear 234 of the intermediate shaft 236 are disengaged, and the cam 231 of the rotating shaft 216 is disengaged. It is placed in the state of FIG. That is, the cam 231 and the cam follower 230 are disengaged from each other at the home position where the rotating shaft 216 is stationary, and the cam follower 230 can rotate around the rotating shaft 229 freely by a predetermined angle.
Therefore, the detection lever 222 can rotate freely by a predetermined angle at the home position where the rotating shaft 216 is stopped by the solenoid 239, and the tip of the detection lever 222 rotates following the sheet stacking amount on the sheet discharge stacker 202. It rotates about a shaft 229, and an actuator 228a integral with the detection lever 222 operates the detection sensor 228 to notify that a predetermined maximum load amount has been reached.
[0050]
Next, the operation of the above-described post-processing apparatus will be described with reference to FIGS.
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 16. At this time, if the operation mode for performing post-processing on the sheet is selected, the switching gate 170 sends the sheet to the connection path 162.
Then, the sheet from the connection path 162 is guided to the carry-in path 207 of the post-processing unit 200, and is carried out to the paper discharge port 204 by carrying-out means (the paper discharge roller 205 and the paper discharge belt 206 shown). In this process, the leading end of the sheet operates the sensor lever 221a, which is detected by the sensor 221, and the subsequent operation is controlled by this timing signal.
At this time, the above-described drive motor M is started to rotate in response to a signal from the image forming unit 100, and rotates the discharge means in the sheet discharge direction. With the rotation of the carrying-out means, the sheet is transported to the right side in FIG. 1, and the leading end of the sheet moves along the transport guide (the support tray 203 shown).
Next, the solenoid 239 is operated after a predetermined time from a sheet leading edge detection signal from the sensor 211 by a delay means such as a timer. Actuation of the solenoid 239 causes the actuator to be disengaged from the latch wheel 238 of the rotating shaft 216, and the rotating shaft 216 is rotated by a predetermined angle by the biasing spring 237. Then, the sector gear 235 of the rotating shaft 216 meshes with the rotating gear 234 connected to the driving motor M, and transmits the rotation of the driving motor M to the rotating shaft 216. The rotation shaft 216 rotates clockwise from the stopped position in FIGS. 1 and 6, and the cam 231 also rotates in the direction of FIG. By the rotation of the cam 231, the cam follower 230 swings the detection lever 222 counterclockwise in the state of FIG. 7 around the shaft 229 by the cam surface 231a.
At this time, the tip of the detection lever 222 is located at a position retracted from the transport trajectory of the sheet moving along the transport guide (the support stacker 203 shown). Subsequently, as the rotating shaft 216 rotates clockwise, the paddle 215 attached to the rotating shaft 216 transports the sheet to the left side of FIG. 7 along the transport guide 203 and moves the sheet to the state of FIG. Line up. In this process, the cam follower 230 of the detection lever 222 slides on the cam surface 231b of the cam 231 and is held at a position (posture) retracted from the sheet transfer trajectory above the discharge stacker 202.
[0051]
The above operation will be described with reference to the state explanatory diagrams of FIGS. 6, 7, and 8. First, in the initial state of FIG. 1, a sheet discharge signal is obtained from the image forming unit 100, and the drive motor of the post-processing unit 200 starts rotating. The rotation of the drive motor M is transmitted to the rotating shaft 210, and rotates the discharge roller 205 and the discharge belt 206 constituting the sheet discharge means so as to discharge the sheet to the right in FIG. At this time, the rotary shaft 216 to which the paddle 215 and the cam 231 are attached is placed in a state where the rotation is stopped by the engagement of the solenoid 239 with the latch wheel 238, and the drive motor M and the rotary shaft 216 are connected to the sector gear 235 and the intermediate shaft 236. The transmission is cut off with the gear disengaged.
[0052]
When the sheet enters the carry-in path 207, the lever 221a of the sensor 221 detects the leading edge of the sheet as shown in FIG. 6, and detects the timing when the leading edge of the sheet reaches the lever position. From the operation signal of the sensor 221, an energization signal is issued from the control circuit to the solenoid 239 at an appropriate timing before the leading end of the sheet reaches the position of the fullness detection lever 222. Then, the solenoid 239 releases the latch wheel 238, and the rotating shaft 216 becomes free (unconstrained). Then, the rotating shaft 216 is urged and rotated by the urging spring 237 so that the sector gear 235 meshes with the gear 234 of the intermediate shaft 214, and the rotation of the drive motor M is transmitted to the rotating shaft 216 via the gear train 232 and the intermediate shaft 236. In FIG. 6, rotation starts clockwise. As the rotation shaft 216 rotates, the cam 231 and the paddle 215 rotate clockwise in FIG. 6, and the cam surface 231a rotates the cam follower 230 counterclockwise about the shaft 229 in the state of FIG. The detection lever 222 is moved to a retracted position above the discharge stacker. In this state, the sheet advances on a conveyance guide (support tray 203 shown in the figure), and the leading end reaches the discharge stacker 202.
[0053]
In a state where the sheet has been completely unloaded onto the conveyance guide, the paddle 215 reversely feeds the sheet in the direction opposite to the unloading direction to the left in the same figure as shown in FIG. It is abutted and stops at the specified position. Thereafter, the paddle 215 separates from the sheet and rotates clockwise with the rotation shaft 216 as shown in FIG. On the other hand, the cam 231 always holds the detection lever 222 at the retracted position with the cam follower 230 at the cam surface 231b on the outer periphery thereof.
Then, when the rotation shaft 216 makes one rotation, the actuator of the solenoid 239 engages with the latch wheel 238 to stop the rotation shaft 216, the sector gear 235 and the intermediate shaft gear 234 are disengaged, and return to the state of FIG. At this time, the detection lever 222 is disengaged from the cam 231 and the cam follower 230, and the lever 222 falls to the sheet discharge stacker 202 side by its own weight, but is kept in contact with the sheet carried out on the conveyance guide. It is.
[0054]
By repeating the above operation, the sheets are sequentially stacked on the transport guide (support tray 203). When a predetermined number of sheets are stacked on the conveyance guide, a job end signal is obtained from the image forming unit, and the post-processing unit 218 performs post-processing such as stapling on the sheet bundle on the conveyance guide. An operation end signal is received from the post-processing means 218, and the rotation of the drive motor M is transmitted to the rotation shaft 241 by the electromagnetic clutch 240 (see FIG. 5). Then, the pulley 210 attached to the rotating shaft 241 rotates the endless belt 218 in the clockwise direction in FIG. 1, and the sheet pushing member 217 attached to the belt 218 pushes the sheet bundle on the conveyance guide 203 rightward in FIG. Therefore, the sheet push-out member 217 constitutes a sheet discharging means of the sheet on the transport guide 203.
[0055]
The sheets extruded on the transport guide are accumulated on the discharge stacker 202, and the detection lever 222 in contact with the uppermost sheet of the sheet is stopped in a posture in contact with the uppermost sheet of the stacked sheets on the discharge stacker. Therefore, the state signal of the sensor 228 is obtained at an appropriate timing after the completion of the unloading operation of the sheet push-out member 217 to determine whether the sheet on the sheet discharge stacker 202 is full. That is, the state where the sensor 228 is operated by the actuator 228a is set to the full position.
[0056]
Although the above-described operation has been described for the case where the sheets are stacked on the transport guide 203, the sheets may be sequentially discharged to the discharge stacker 202 without loading the sheets on the transport guide 203. In this case, the sheet pushing member (sheet discharging means) is operated in the state of FIG. 8 described above, that is, in a state where the detection lever 222 is held at the retracted position by the cam 231, and the sheet on the conveying guide 203 is discharged. Should be sent to
[0057]
【The invention's effect】
According to the present invention, as described above, the detection lever for detecting the stacking amount of the sheets on the sheet discharge stacker is configured to swing freely from the upper side to the lower side along the movement trajectory of the sheet from the transport guide to the sheet discharge stacker. Since the detection lever is held at the upper evacuation position when discharging the sheet, the stacking amount of the central portion of the sheet on the stacker can be detected. It is possible to prevent an improper amount of stacking from being detected by detecting a partially swollen sheet corner of a sheet or the like. Further, when the sheet is carried into the sheet discharge stacker, the detection lever is held in a posture retracted upward from the sheet passage path and does not hinder the sheet.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a main part of a post-processing device that implements the present invention.
FIG. 2 is a vertical sectional view showing the entire post-processing apparatus and image forming apparatus using the present invention.
FIG. 3 is an illustration of a different cross section of the device of FIG. 2;
FIG. 4 is a perspective view illustrating a driving mechanism of the apparatus of FIG.
FIG. 5 is an illustration of a drive mechanism of a post-processing unit of the apparatus of FIG.
6 is an explanatory diagram of an operation state of a detection lever in the device of FIG.
FIG. 7 is an explanatory diagram of an operation state of a detection lever in the device of FIG. 2;
8 is an explanatory diagram of an operation state of a detection lever in the device of FIG.
[Explanation of symbols]
REFERENCE SIGNS LIST 100 Image forming unit 200 Post-processing unit 202 Discharge stacker 203 Transport guide 205 Discharge means (discharge roller)
206 Unloading means (paper ejection belt)
207 Carrying path 216 Rotating shaft 217 Paper discharging means (sheet pushing member)
222 Detection lever 229 Shaft 230 Cam follower 231 Cam 300 Image reading unit 350 Document feed unit M Driving means

Claims (7)

A conveyance guide for conveying the sheet,
Sheet discharging means provided on the transport guide for sequentially discharging sheets;
A stacker arranged with a step below the sheet discharging means,
A sheet height lever in contact with the top of the sheet discharge stacker,
A detection sensor for detecting the position of the detection lever,
The detection lever is configured to be swingable between a retreat position above the sheet and a detection position where the detection lever comes into contact with the lower sheet discharge stacker over a movement locus of the sheet from the sheet discharge means to the sheet discharge stacker,
An operating device for connecting the detecting lever to an operation means for holding the detecting lever at the retracted position when a sheet is discharged. The operating means of the detection lever moves from the upper retracted position to the discharge stacker by its own weight,
2. The sheet stacking apparatus according to claim 1, further comprising a driving source that moves from a lower discharge stacker to a retracted position. 3. The sheet according to claim 2, wherein a driving source of the operating unit is configured in common with a driving source of the sheet discharging unit, and a cam unit that regulates an operation timing is provided between the operating unit and the driving source. Integrated device. A sheet stacking apparatus, wherein the transport guide is configured in a tray shape on which a sheet is temporarily placed, and is provided with post-processing means such as a sheet punching stapler binding placed on the transport guide. Sheet conveying means for sequentially conveying the sheets,
A tray-shaped conveyance guide for temporarily placing sheets from the sheet conveyance means, and a paper discharge means provided on the conveyance guide for discharging the sheets,
A discharge stacker arranged with a step below the discharge means,
A sheet height detection lever in contact with the uppermost sheet of the discharge stacker;
Equipped with a detection sensor that detects the position of this detection lever,
The detection lever is configured to be movable between a retracted position provided above a movement trajectory of the sheet from the sheet conveyance means to the conveyance guide and a detection position in contact with the uppermost sheet of the discharge stacker,
A sheet stacking apparatus, wherein an actuating means for holding the detection lever at a retracted position when transferring a sheet from the sheet conveyance means to the conveyance guide is connected to the detection lever. 6. The sheet stacking apparatus according to claim 5, wherein post-processing means such as punching sheets and stapling the sheets is provided in the tray-shaped conveyance guide. Sheet discharging means for sequentially discharging sheets,
A tray-shaped conveyance guide that temporarily holds the sheet from the sheet unloading unit, a post-processing unit that performs post-processing on the sheet on the conveyance guide,
Sheet discharging means for conveying a sheet from the conveying guide to a sheet discharging stacker;
A sheet height detection lever that contacts the uppermost sheet on the discharge stacker;
Sensor means for detecting this detection lever,
The detection lever is moved from an upper retreat position to a lower discharge stacker through a sheet movement path from the sheet discharging means to the conveyance guide and a sheet movement path from the discharge guide to the discharge stacker. It is configured to be able to swing between the contacting detection position,
A sheet post-processing apparatus, wherein an operating means for holding the detection lever at the retracted position is connected to the detection lever when the sheet is transferred from the sheet discharge means to the discharge stacker.

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