JP2008137731A - Sheet stacking device and image forming system equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet stacking device storing sheets carried out of a paper delivery port, tidily on a tray. <P>SOLUTION: The sheet stacking device comprises the paper delivery port 21b; the tray 25 disposed with level difference formed downstream of the delivery port; a tip regulating means 33 disposed on the tray to butt-regulate the sheet tip; an aligning means 29 transferring the tip of the sheet fed onto the tray, toward the tip regulating means 33; and an upper unit 28 arranged above the tray and equipped with the tip regulating means 33 and the aligning means 29. The tip regulating means 33 is provided to hang down to the tray 25 from the upper unit 28, and the aligning means 29 is composed of an adjusting rotation body 29a engaged with the tip of the sheet stacked on the tray 25 to butt-adjust it against the tip regulating means 33. The adjusting rotation body comprises a belt conveying means for guiding the tip of the sheet from the paper delivery port onto the tray. The upper unit 28 is constituted to be movable according to the conveying direction length of the sheet from the paper delivery port 22b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet stacking apparatus that stacks and stores sheets sequentially conveyed from an image forming apparatus such as a copying machine and a printer on a tray unit, and relates to an improvement of a sheet discharge mechanism that stacks and stores sheets discharged at high speed in a large capacity. .

  Generally, this type of sheet stacking apparatus is widely used to stack and store sheets carried out from an image forming apparatus such as a printing machine or a copying machine on a tray means disposed below a sheet discharge port. This type of device forms a step at the discharge outlet of the image forming apparatus and provides a tray. The sheet is then carried out with the discharge rollers and belt provided at the discharge outlet, and the sheets are stacked and stored on the tray. is doing.

  In such a sheet storage device, when a sheet is fed to the paper discharge port at a high speed (for example, the sheet carry-out speed is 100 sheets / min or more), the sheet scatters when the sheet falls from the paper discharge port onto the tray means. Alternatively, it may be accumulated in a distorted posture on the tray. In order to stack a large amount of sheets on the tray, when the tray is lowered stepwise according to the stacking amount, it is necessary to set a large level difference between the discharge outlet and the tray, and the sheet falls. There is a risk of being accumulated on the tray in a distorted posture.

  Therefore, in order to stack such high-speed discharged sheets on the tray in a large capacity and orderly, for example, Patent Document 1 discloses a traveling type conveying means that nips the front end of the sheet above the tray and transfers it from the discharge port to the front end of the tray. In this publication, the belt means is provided with a grip mechanism for nipping the front end of the sheet, the front end of the sheet carried out from the paper discharge port is nipped and guided to the front end of the tray, and the entire sheet is discharged from the paper discharge port. An apparatus for dropping onto a tray while being unloaded is disclosed.

  Further, in Patent Document 2, a roller unit is disposed above the front end side of the tray, and a belt that guides the sheet from the discharge port to the roller by abutting the front end of the sheet from the discharge port with the roller unit. An equipped device has been proposed.

On the other hand, a device provided with a stopper means for restricting butting the leading edge of the sheet with such a sheet stacking device and an alignment roller for transferring the sheet to the stopper device is disclosed in, for example, Japanese Patent Application Laid-Open No. H10-228707. No configuration is disclosed for guiding the sheet carried on the tray to the alignment roller.
JP 2003-341908 A JP 2003-171054 A JP-A-1-167166

  As described above, in order to store the sheets that are carried out from the paper discharge port at high speed on the tray means, the leading and trailing ends of the sheet are regulated by the regulating member, and the sheet falls from the paper ejection port onto the tray. It is necessary to be easy so that the posture is not disturbed. On the other hand, conventionally, for example, as disclosed in Patent Document 1, the sheet is nipped and guided to the leading edge of the tray, or as disclosed in Patent Document 2, the sheet from the paper discharge port is conveyed by a vacuum conveying means. Then, it is guided to the aforementioned roller means and aligned on the tray. Therefore, the conventional apparatus has a conveying means (the belt means or vacuum conveying means described above) above the tray, and the control of the conveying means must be controlled at the same speed as the sheet conveying speed from the discharge port. However, there is a problem that it is complicated and large.

  Therefore, it is required to guide the sheet discharged from the sheet discharge outlet in an orderly manner to the front end of the tray. However, since the apparatus disclosed in the above-mentioned Patent Document 1 is provided with a front end abutting stopper and an alignment roller means fixed to the front end of the tray, a plurality of sheets having different sheet length sizes are stacked on the tray. However, there is a problem that the position of the sheet is only regulated with respect to the front end of the sheet, and the curled sheet cannot be collected in an orderly manner due to breakage of the front end.

  On the other hand, in the above-mentioned Patent Document 3, there is proposed a device provided with a stopper means for restricting butting the leading edge of the sheet and an alignment roller for transferring the sheet to the stopper means. Since there is no means for preventing the lifting, the sheet is curved between the roller and the stopper, and the reaction of the reaction causes the sheet to collapse.

SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to provide a sheet stacking apparatus that can reliably store sheets carried out at high speed from a sheet discharge outlet on a tray and simultaneously stack them in a correct posture. Another object of the present invention is to provide a sheet stacking apparatus capable of guiding a sheet carried out from a sheet discharge outlet in a correct posture on a tray and positioning and storing the sheet at a predetermined position.
Another object of the present invention is to provide a sheet stacking apparatus capable of orderly storing a plurality of sheets having different length sizes on the tray means.

  The present invention adopts the following configuration in order to solve the above problems. A sheet discharge outlet 21b for sequentially carrying out the sheets, a tray means 25 arranged with a step formed downstream thereof, and stacking and storing the sheets, and a sheet leading edge from the sheet discharge opening disposed at the front end of the tray means. The leading edge restricting means 33 for restricting the position by contact, the aligning means 29 for transferring the leading edge of the sheet sent onto the tray means 25 toward the leading edge restricting means 33, and the leading edge restricting means 33 and the aligning means disposed above the tray means. And an upper unit 28 on which a lining means 29 is mounted. The leading edge regulating means 33 is provided so as to hang from the upper unit 28 to the tray means 25, and the aligning means 29 engages with the leading edge of the sheets stacked on the tray means 25 and abuts against the leading edge regulating means 33. The aligning rotator 29a includes a belt conveying unit 29b for guiding the leading end of the sheet from the sheet discharge port onto the tray unit, and the upper unit 28 conveys the sheet from the sheet discharge port 22b. It is configured to be movable according to the direction length.

  The alignment rotating body is either (1) a belt member that is stretched between a pair of pulleys and has one end engaged with a sheet on the tray means, or (2) a roller member positioned on the tray means and the roller member It consists of a transmission belt that rotates. Then, driving means for driving the belt member or the transmission belt is mounted on the upper unit 28.

  The belt member or the roller member is attached to the upper unit 28 so as to be movable up and down according to the stacking amount of the sheets stacked on the tray means 25. Further, the upper unit 28 is provided with a pressing guide member 28b between the aligning rotating body 29a and the leading end regulating means 33 for preventing the sheet from curling up.

  Guide means (guide belt) 30 for guiding the upper surface of the sheet from the paper discharge port 22b to the alignment rotator 29a is provided between the paper discharge port 22b and the alignment rotator 29a. It is composed of an entraining belt or the like that can be expanded and contracted with movement of the belt.

  The belt conveying means 29b is constituted by a belt-like belt member, and the belt-like belt member 29b is configured such that one end on the paper discharge port side is swingably supported on the upper unit 28 and the tip on the tray means side is movable up and down. The tray means 25 is configured to descend downward from the sheet discharge outlet according to the sheet stacking amount.

  A sheet discharge means 23 for carrying out the sheet is disposed at the sheet discharge port, and the aligning rotating body applies the conveyance speed lower than the conveyance speed at which the sheet discharge means acts on the sheet to thereby change the speed difference. The speed is set so that the rear end of the sheet is curved.

  A sensor Se1 for detecting the leading edge of the sheet is provided at the discharge port, and the control means 70 for controlling the aligning means 29 is information (detection signal) that the sheet has reached the discharge port 22b and the length in the sheet conveyance direction. Based on the information, the alignment rotator 29a is rotated and / or stopped. In this case, the control unit 70 is configured to obtain the sheet conveyance direction length information from an external apparatus such as an image forming apparatus disposed on the upstream side of the sheet discharge port 22b.

  The control means 70 for controlling the aligning means 29 decelerates at a lower speed than the speed at which the trailing edge of the sheet is carried out from the discharge outlet immediately before the leading edge of the sheet from the discharge outlet 22b reaches the leading edge regulating means 33. Further, the image forming apparatus of the present invention comprises an image forming apparatus having an image forming means for forming an image on a sheet, and a sheet stacking apparatus for stacking and storing sheets from the image forming apparatus. In this case, the sheet stacking apparatus Has the above-described configuration.

  The present invention includes a front end restricting unit that restricts a sheet against the front end of the tray when the sheet is unloaded from the discharge port to a tray unit disposed below, an alignment rotating body that transfers the sheet to the restricting unit, Since the aligning rotator is provided with a belt member for guiding the sheet, the sheet from the sheet discharge port is guided to the belt conveying means without being scattered outside the tray, and even if the sheet has a curled tip. Therefore, it is guided by the aligning rotator and can be neatly accumulated on the tray. Therefore, it is not necessary to arrange a conveying means for conveying the sheet above the tray as in the prior art, and the apparatus can be configured to be small and compact.

  Further, by providing pressing guide means for preventing the sheet from curling up between the aligning rotator and the leading edge regulating means, the leading edge of the sheet can be prevented from being bent. In addition, by providing a telescopic guide member for regulating the upper surface of the sheet between the aligning rotator and the sheet discharge port, even a curled sheet or a thin paper sheet can be smoothly positioned and stored in the leading edge regulating means.

  The alignment rotating body starts rotating immediately before the leading edge of the sheet reaches the leading edge restricting means, and stops when the sheet reaches the leading edge restricting means, so that the aligning rotating body conveys the sheet more than necessary. No wrinkles or damages are caused. Further, by decelerating the alignment rotating body immediately before the leading edge of the sheet reaches the leading edge restricting means, the impact when hitting the leading edge restricting means is small, and the sheet bounce can be suppressed.

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 is an overall configuration diagram of an image forming system provided with a sheet stacking apparatus according to the present invention, and FIG. 2 is a configuration explanatory diagram of a tray stacking unit of the sheet stacking apparatus. 3A and 3B are explanatory views of the upper unit, wherein FIG. 3A is a front view thereof and FIG. 3B is a perspective view thereof.

[Image forming system]
The image forming system shown in FIG. 1 includes an image forming apparatus A and a sheet stacking apparatus B, and the sheet stacking apparatus B is configured to stack and store sheets formed with the image forming apparatus A on a tray of the sheet stacking apparatus B. It is connected to the main body discharge port 3 of the image forming apparatus A. Hereinafter, the image forming apparatus A and the sheet stacking apparatus B will be described in this order.

[Image forming apparatus]
First, an example of an image forming apparatus for forming an image on a sheet is shown in FIG. 1 and will be described. The image forming apparatus A shown in FIG. 1 sends a sheet from the paper supply unit 1 to the image forming unit 2, prints the sheet on the image forming unit 2, and then carries the sheet out from the main body discharge port 3. The sheet feeding unit 1 stores sheets of a plurality of sizes in sheet feeding cassettes 1 a and 1 b, and separates designated sheets one by one and feeds them to the image forming unit 2. The image forming means 2 includes, for example, an electrostatic drum 4, a print head (laser light emitting device) 5 and a developing device 6 arranged around the electrostatic drum 4, a transfer charger 7, and a fixing device 8. An electrostatic latent image is formed by the light emitting device 5, toner is adhered to the developing device 6, an image is transferred onto the sheet by the transfer charger 7, and heat fixing is performed by the fixing device 8. The sheets on which images are formed in this way are sequentially carried out from the main body discharge port 3. 9 is a circulation path, which is a double-sided printing path in which a sheet printed on the front surface from the fixing device 8 is reversed and fed again to the image forming unit 2 and printed on the back surface of the sheet. The sheet printed on both sides in this way is turned upside down by the switchback path 10 and then carried out from the main body discharge port 3.

  11 is an image reading apparatus, which scans a document sheet set on a platen 12 with a scanning unit 13 and electrically reads it with a photoelectric conversion element (not shown). The image data is digitally processed by an image processing unit, for example, and then transferred to the data storage unit 14 to send an image signal to the laser emitter 5. 15 is a document feeder, which is a feeder device that feeds a document sheet stored in the document stacker 16 to the platen 12.

[Sheet Accumulator]
Next, the sheet stacking apparatus B will be described. The illustrated sheet stacking apparatus B includes a sheet carry-in path 21 disposed in a suitably shaped housing 20 (see FIG. 1), a tray unit 25, and an upper unit 28. The upper unit 28 includes a sheet leading edge regulating unit 33 and an upper unit 28. A lining means 29 and a guide means 30 (a winding belt described later) are mounted. Then, the sheet is unloaded from the sheet discharge port 22 b of the sheet loading path 21 to the tray unit 25. Above the leading end side of the tray means 25, a sheet leading edge regulating means 33 hanging from the upper unit 28 abuts and regulates the sheet leading edge to align on the tray means 25. At this time, the sheet from the paper discharge port 22b is sent to the sheet leading edge regulating means 33 by the aligning means 29 so that skew correction or registration correction is performed. Each configuration will be described below.

[Sheet carry-in route]
The sheet carry-in path 21 is configured by a paper guide in a path having a sheet receiving port 22a and a sheet discharge port 22b, and the sheet carry-in path 21 is provided with a sheet discharge unit 23 for conveying the sheet. As shown in FIG. 2, the paper discharge means 23 is composed of a driving roller 23a and a driven belt 23b (or a driven roller), and carries the sheet from the receiving port 22a to the paper discharge port 22b. In addition, air blowing means 24 having an air outlet is disposed in the sheet carry-in path 21, and at the same time the sheet in the path is cooled, the sheet from the sheet discharge port is conveyed to an entraining belt (guide means) 30 described later by an air flow. It comes to lead. Se1 shown in the drawing is a paper discharge sensor for detecting the leading edge and the trailing edge of the sheet.

[Configuration of tray means]
The tray means 25 is composed of a paper platform (hereinafter referred to as “tray 25”) on which sheets are stacked, and is configured to be capable of placing a maximum size sheet in a substantially horizontal posture. The illustrated tray 25 is composed of a tray member separated from the apparatus frame 26 so that it can be transported to the outside of the apparatus in the form of a pallet, and is detachably mounted on the tray lifting / lowering means 31 described below.

[Tray lifting means]
As shown in FIG. 5, the tray lifting / lowering means 31 for mounting the tray 25 is composed of fork-like lifting arms 31a and 31b (fork members; the same applies hereinafter) mounted on the apparatus frame 26 so as to be movable up and down. The elevating arms 31a and 31b are provided with guide rails 32a and 32b on the apparatus frame 26, and are guided along the guide rails in the stacking direction (vertical direction in FIG. 5) so as to be movable up and down. The elevating arms 31a and 31b are suspended by a pulling member 37 such as a wire or belt that is stretched around a suspension pulley 36 fixed to the apparatus frame 26. The pulling wire (traction member) 37 shown in the figure is connected to a take-up pulley 38. ing. A lifting motor M3 is connected to the winding pulley 38. Accordingly, the lifting arms 31a and 31b are supported by the guide rail 32 of the apparatus frame 26 and moved up and down by the lifting motor M3. The tray 25 is mounted on the lifting arms 31a and 31b and moves up and down according to the stacking amount below the paper discharge port 22b. The elevating arms 31a and 31b are provided with a rear end regulating member 26a for regulating the rear end of the sheet. The rear end of the sheet from the sheet discharge port 22b is projected on the tray 25 mounted on the elevating arms 31a and 31b. They are placed on top of each other after being regulated.

[Tray lifting control]
The lift arms 31a and 31b are provided with an upper limit position sensor Sp2 for detecting the upper limit position, a maximum stack position sensor Sp3 for detecting the maximum stack position, and a lower limit position sensor Sp4 for detecting the lower limit position. The control means 70 of the lifting motor M3, which will be described later, moves the lifting arms 31a and 31b up and down by rotationally driving the lifting motor M3 in response to the paper level sensor Sp1 and the detection signals of the sensors.

[Configuration of upper unit]
An upper unit 28 is provided above the tray 25 described above. As shown in FIG. 2, the upper unit 28 is supported by the apparatus frame 26 so as to be movable in the paper discharge direction (left-right direction in FIG. 2), and the sheet front end restricting means 33 that abuts and regulates the front end of the sheet from the paper discharge port 22b. And aligning means 29 are mounted. The upper unit 28 is slidably supported on a guide rail 26b provided on the apparatus frame 26 and is movable in the left-right direction in FIG. A unit moving motor M1 is connected to the unit moving belt 28v, and the position of the upper unit 28 in the paper discharge direction can be changed by the unit moving motor M1. The reason why the upper unit 28 is moved in the paper discharge direction is that the following sheet leading edge regulating means 33 adjusts the position according to the sheet size (length in the sheet discharge direction).

[Configuration of sheet tip regulating means]
The upper unit 28 is provided with sheet leading edge regulating means 33. As shown in FIG. 2, the sheet leading edge restricting means 33 includes a fixed stopper piece 33a and a movable stopper piece 33b attached to the upper unit 28. The fixed stopper piece 33a is fixed to the unit frame 28a, and the upper unit 28 is controlled to move so that the distance Ls between the front end (lower end) and the rear end regulating member 26a coincides with the length in the sheet discharge direction (non-jog unloading). When) Further, a movable stopper 33b is disposed at a position that is spaced from the fixed stopper 33a by a jog interval Lg. The movable stopper 33b is fitted and supported on the unit frame 28a so as to be movable up and down, and is moved up and down by a stopper motor M2. In the illustrated example, a rack gear Pr is provided at the base end of the movable stopper 33b, and a stopper motor M2 is connected to a pinion Pn that meshes with the rack gear Pr. The movable stopper 33b is controlled by a stopper motor M2 so as to be movable up and down between an operating position where the movable stopper 33b engages with a sheet on the tray 25 and a retracted position retracted in the unit frame 28a.

  The reason why the first and second two stopper pieces 33a and 33b are provided at positions offset by a predetermined amount (the jog interval Lg) in the paper discharge direction is to align the sheets from the paper discharge port 22b. This is to make a quantitative offset. That is, when the movable stopper 33b is positioned at the operating position and the sheets from the sheet discharge port 22b are stacked on the tray, the movable stopper 33b is positioned at the retracted position and the sheets from the sheet discharge port 22b are stacked on the tray. In this case, the sheets are stacked at a position separated from the front and rear by the jog interval Lg. During the jog unloading (jog mode), the upper unit 28 is controlled to move so that the distance Ls between the trailing end regulating member 26a and the movable stopper 33b matches the length in the sheet conveyance direction.

[Configuration of aligning means]
The upper unit 28 is provided with aligning means 29 on the front side (upstream side) of the sheet leading edge regulating means 33 in the paper discharge direction. This aligning means 29 is for correcting the registration (unreachable) and skew (leading-end bending) of the sheet leading edge by transferring the leading edge of the sheet carried out on the tray 25 toward the sheet leading edge regulating means 33. . Therefore, the aligning means 29 is attached to the upper unit 28, and is composed of a rotating body 29a such as a roller and a belt, and is disposed at a position where the aligning means 29 engages with a sheet on the tray 25 (a sheet carried in from the sheet discharge port). . This alignment rotating body is either (1) a belt member that is stretched over a pair of rotating bodies and has one end engaged with a sheet on the tray, or (2) a roller member that engages with a sheet on the tray and this roller member It consists of a transmission belt that rotates.

  The alignment rotating body shown in FIG. 2 includes a roller member 29a and a transmission belt 29b that drives and rotates the roller member 29a. That is, as shown in detail in FIG. 3, a rotating shaft 29c is attached to the upper unit 28, and a bracket 29d is swingably supported on the rotating shaft 29c. A roller member 29a is rotatably supported by the bracket 29d, and a transmission belt 29b is stretched between the rotation shaft 29c and the roller member 29a. A drive motor M8 is connected to the rotary shaft 29c. When the rotary shaft 29c is rotated by the drive motor M8, the transmission belt 29b and the roller member 29a connected thereto are rotated.

  In particular, as shown in FIG. 4, the transmission belt 29b is configured so that the sheet from the sheet discharge port 22b is guided to the roller member 29a by a backup member 29e (bottom wall of the unit) formed on the unit frame 28a. It is arranged in the movement trajectory. The roller members 29a are arranged at two locations in the sheet width direction at predetermined intervals. The illustrated one has an apparatus configuration for discharging the sheet from the sheet discharge port 22b based on the center, and therefore, two roller members 29a (see FIG. 4B) are arranged at a predetermined interval from the center of the sheet to the left and right. Regardless of the configuration described above, the alignment rotating body 29a suspends a belt member between a pair of pulleys, and the front end of the belt member is inclined on the tray so that the front end of the belt engages with the sheet on the tray. May be.

[Structure of presser guide]
The upper unit 28 is equipped with the sheet leading edge regulating means 33 (fixed stopper 33a, movable stopper 33b) and the alignment rotating body 29a as described above. At the same time, a pressing guide 28b is provided for preventing the sheet from being pushed up when the alignment rotating body 29a transfers the sheet to the sheet leading edge regulating means 33. At the bottom of the unit frame 28a, a guide plate is provided between the aligning rotator 29a and the sheet leading edge restricting means 33 to form a small gap between the sheet on the tray and guide the sheet. 28b is constituted. This is to prevent the sheet from being bent when the leading end of the sheet is transferred to the sheet leading end regulating means 33 by the alignment rotating body 29a.

[Configuration of entrainment belt (guide means)]
Between the above-mentioned upper unit 28 and the paper discharge port 22b, a winding belt (guide means; the same applies hereinafter) 30 for guiding the upper surface of the sheet from the paper discharge port is disposed. One end of the entrainment belt 30 is supported by the upper unit 28 and the other end is supported by the apparatus frame 26 in the vicinity of the paper discharge port 22a. This is because the sheet from the paper discharge port 22a is thin or curled, and is scattered outside the tray, or the posture may be collapsed while reaching the sheet leading edge restricting means 33, thereby preventing this. It is to do. Accordingly, various belts can be used as the winding belt 30 as long as the upper surface of the sheet is guided so as to form a movement locus of the sheet between the sheet discharge port 22b and the sheet leading edge regulating unit 33. The illustrated entraining belt (guide means; hereinafter referred to as “guide belt”) 30 is formed of a synthetic resin film member such as a polyethylene film (mylar), and the belt tip is fixed to the shaft 28 c of the upper unit 28. The other end of the belt is fixed to a winding pulley 30P that is rotatably attached to the apparatus frame 26. Although not shown in the drawing pulley 30P, a spring is wound, and the pulley is always urged in the winding direction. This is because the guide belt 30 is expanded and contracted by the action of the spring so that the upper unit 28 is moved forward and backward by the unit moving motor M1. In addition, 30t in the drawing is a tension spring, and the winding pulley 30P may be provided on the upper unit 28 side.

[Seat side alignment means]
As described above, the sheet from the paper discharge port 22b is guided to the front end side of the tray by the guide belt 30, and when the front end of the sheet reaches the aligning rotating body 29a, the rotating body acts and is regulated against the sheet front end restricting means 33. . Therefore, the sheet side regulating means 54 for positioning and regulating the side edge of the sheet stored on the tray means 25 to correct the width direction posture of the sheet is arranged as follows. The seat side regulating means 54 includes a pair of alignment plates 54a and 54b on the left and right side edges (front and rear in FIG. 2) of the seat. As shown in FIG. 2, the rear side alignment plate 54 b and the front side alignment plate 54 a that regulate the sheet side edge on the back side of the apparatus are arranged so as to hang downward from the upper side of the tray 25. Both alignment plates 54a and 54b (hereinafter collectively referred to as “alignment plate 54”) are supported by a shaft member 54c and moved in the left-right direction in FIG.

  The illustrated aligning plate 54 is movable to an engagement position X (see FIG. 6) that engages with the sheet side edge, a standby position Y that is slightly separated from the sheet side edge, and a retracted position Z that is sufficiently separated from the sheet side edge. The shaft member 54c is fitted and supported. A pair of left and right shift levers 56a and 56b connected to the width adjusting motor M4 are connected to the alignment plate 54, and both levers are engaged with a pinion M4p of the width adjusting motor M4. Accordingly, the alignment plate 54 moves in accordance with the width size of the sheet by the rotation of the pinion M4p. That is, the rear side and front side alignment plates 54a and 54b are moved to a position suitable for the width size of the sheet by the rotation of the width adjusting motor M4, and at this position, the standby position Y slightly separated from the sheet side edge and the sheet side edge It will reciprocate between the engaged position (actuated position) X and the forward / reverse rotation of the pinion M4p.

[Sheet rear edge pressing means]
A sheet trailing edge pressing means 58 is provided for striking the trailing edge of the sheet toward the tray in the process of dropping the sheet onto the tray 25 together with the sheet side alignment means 54. As shown in FIG. 8, the sheet trailing edge pressing means 58 is disposed on the upper downstream side of the sheet discharge port 22b, and a sheet-like tapping piece 58a that strikes the sheet trailing edge from the sheet discharge port 22b on the lower tray 25. I have. The hit piece 58 a is inserted into a support cylinder 59 fixed to the apparatus frame 26 and connected to the drive lever 60. A drive motor M5 is connected to the drive lever 60, and the drive lever 60 swings at a predetermined angle by forward / reverse rotation of the motor. A hitting piece 58a connected to the drive lever 60 moves up and down between the solid line and the chain line in FIG. Will move. Accordingly, the sheet that is separated from the sheet discharge port 22b and is transported toward the sheet leading edge regulating means 33 by the aligning rotating body 29a is knocked down by the tapping piece 58a and stored on the tray. Become. This is to prevent the leading edge of the sheet sent subsequent to the sheet discharge outlet and the trailing edge of the preceding preceding sheet from dropping from interfering with each other.

[Tray paper holding means]
The tray 25 mounted on the tray lifting / lowering means 31 is provided with a paper pressing means 61 for pressing and holding the stacked sheets. The details are shown in FIG. 7, but a pair of left and right paper pressing members 61a and 61b (hereinafter collectively referred to as “paper pressing member 61”) that press and hold the sheet side edge orthogonal to the paper discharge direction are applied to the sheets stacked on the tray 25. The sheet pressing member 61 is retracted from the tray when the sheet falls, and presses the uppermost sheet after the sheet is dropped and stored. For this reason, the illustrated paper pressing member 61 includes an arm-shaped paper touch piece 62 a and a cylinder cam 62 b, and the cylinder cam 62 b is fixed to the apparatus frame 26. The cylinder cam 62b is formed with an inclined cam groove 62c for rotating the paper touch piece 62a according to the vertical movement. The paper touch piece 62a is provided with a pin 62d that is fitted to the cylinder cam 62b and engages with the inclined cam groove, and an arm 63 connected to the vertical movement motor M6 is fitted to the paper touch piece 62a.
Accordingly, when the motor M6 is driven in the direction of the arrow in FIG. 7C, the arm 63 pulls the paper touch piece 62a upward. At this time, the pin 62d of the paper touch piece 62a is rotated approximately 90 degrees by the inclined cam groove 62c of the cylinder cam 62b, and at the same time the paper touch piece 62a moves upward from the state of FIG. Move to the retreat position by swinging 90 degrees. Spa shown in the drawing is a position sensor for the paper touch piece 62a, and the position is detected with the retracted position as the home position.

Hereinafter, a sheet discharge operation in the above-described apparatus will be described.
"Job start operation"
When the control unit 70 of the sheet stacking apparatus B (for example, a control CPU of the sheet stacking apparatus B; not shown) receives the discharge instruction signal from the image forming apparatus A, the sheet stacking unit B drives and rotates the discharge unit 23. Then, the sheet from the main body discharge port 3 of the image forming apparatus A is guided to the sheet carry-in path 21.
"Ejecting initial operation"
The sheet guided to the sheet carry-in path 21 is gradually conveyed onto the tray 25 by the sheet discharge means 23 from the sheet discharge port 22b. This state is shown in FIG. 9A, and the sheet is regulated and guided at the center in the width direction by the guide belt 30 (guide means) and is transferred to the tray front end side. At this time, when the average sheet S1 is unloaded from the paper discharge means 23, it comes into contact with the point f1 of the guide belt 30 along the locus shown in FIG. Further, the sheet S2 curled upward contacts the f2 point and is guided in the F direction, and the thin sheet S3 such as a thin paper sheet contacts the f3 point and is guided in the F direction. In the figure, FS indicates the direction of action of the conveying force applied to the sheet. Therefore, when the leading edge of the sheet comes into contact with the guide belt 30, all the sheets are guided and guided in the F direction along the guide belt, and the transmission belt 29b and the aligning rotating body 29a are disposed at the leading end of the guide belt 30.

"Sheet alignment operation"
Therefore, the control means 70 drives the drive motor M8 to rotate after a predetermined delay time (t1) from the signal that the paper discharge sensor Se1 detects the leading edge of the sheet. The drive motor M8 rotates the transmission belt 29b in the direction of the arrow in FIG. The delay time t1 is an expected time for the leading edge of the sheet to reach the transmission belt 29b, and varies depending on the sheet length. For this reason, the control means 70 calculates the start timing based on the sheet size (conveyance direction length) information and the detection signal from the paper discharge sensor Se1. When the delay time t1 has elapsed, the control means 70 starts to rotate the drive motor M8 to rotate the alignment rotating body 29a. At this time, the rotational speeds of the transmission belt 29b and the alignment rotating body 29a are set to the same speed as the conveying speed applied to the trailing edge of the sheet by the paper discharge means 23, or to a speed lower than this speed. This state is shown in FIG. 10A. In the case of the same speed, the front end of the sheet is guided by the transmission belt 29b at the same speed as the rear end of the sheet carried out from the paper discharge port 22b and aligned with the uppermost sheet on the tray 25. It is guided between the rotating body 29a and conveyed toward the sheet leading edge regulating means 33.

  On the other hand, when the aligning rotator 29a is set at a lower speed than the sheet discharge means 23, the sheet center is conveyed toward the sheet front end restricting means 33 by the aligning rotator 29a while the sheet central portion and the rear end are curved. Although this state is shown in FIG. 10B, since the sheet rear end side is curved when it abuts against the sheet front end restricting means 33, a stronger front end bend such as a hip hitting skew is corrected and rebound is less likely. Therefore, it is preferable that the aligning rotator 29a rotate at the same speed as the sheet discharge means 23 or at a lower speed than the sheet discharge means. If the rotation speed of the align rotator 29a is set according to the apparatus specifications, particularly the properties of the sheet to be conveyed. good. In this way, the pressing guide 28b prevents the leading edge of the sheet from approaching the upper unit 28 while the leading edge of the sheet is conveyed to the leading edge regulating means 33 by the aligning rotating body 29a. In particular, in the case of a sheet curled with thin paper, the press guide 28b can prevent the leading end of the sheet from being pushed up by the aligning rotating body 29a.

"Sheet trailing edge pressing means operation and paper pressing member retraction operation"
The control means 70 moves the paper contact pieces 62a and 62b of the paper pressing means 61 to the retracted position after a predetermined time from the rear end detection signal of the paper discharge sensor Se1 after the rear end of the sheet is detached from the paper discharge means 23. This movement to the retracted position is performed by moving the paper touch piece 62 to the retracted position shown in FIG. At the same time, the control means 70 rotates the drive motor M5 of the sheet trailing edge pressing means 58 to swing the drive lever 60 clockwise in FIG. Then, the hitting piece 58a vigorously hits the rear end of the sheet downward, and accumulates the rear end of the sheet on the tray. At this time, since the leading edge of the sheet is held (pressed) between the alignment rotating body 29a and the uppermost sheet on the tray, the posture of the sheet is not lost.

`` Aligned rotating body speed control ''
Concurrently with the sheet trailing edge pressing operation, the control means 70 reduces the speed of the alignment rotating body 29a to a predetermined speed. This speed is set so as not to cause damage such as bending of the leading edge when the leading edge of the sheet hits the leading edge regulating means 33. In this speed control, the control unit 70 calculates the expected time immediately before the sheet leading edge reaches the sheet leading edge regulating means 33 based on the sheet size (length in the sheet discharging direction) information and the signal when the sheet discharging sensor Se1 detects the sheet leading edge. Then, after this delay time t2, the speed of the drive motor M8 is reduced.

"Alignment rotating body stop operation"
Next, the control means 70 stops the rotation of the drive motor M8 after the expected time t3 when the sheet leading edge is stopped against the sheet leading edge regulating means 33. The expected time t3 is calculated by the control means 70 in the same manner as the delay times t1 and t2 described above.
"Seat-side alignment operation"
Concurrently with the stop of the aligning rotating body 29a, the control means 70 starts the width adjusting motor M4 at the timing when the sheet is stored on the tray 25 and moves the aligning plates 54a and 54b from the standby position to the operating position. Then, the sheets stacked on the tray are aligned and aligned (see FIG. 6).
"Tray paper presser return operation"
Next, the control means 70 drives the vertical movement motor M6 to return the holding means 61 at the standby position to the operating position on the tray (state shown in FIG. 7A).

  By repeating the above operation, the sheets sent to the paper discharge port 22b are stacked and stored on the tray 25. When the sheet level sensor Sp1 detects a predetermined amount of sheet stacking, the control means 70 moves down the lifting arms 31a and 31b by a certain amount. When the elevating arms 31a and 31b are lowered to the position of the maximum loading capacity set in advance, the control means 70 determines that it is full. At the time of full detection or in response to a job end signal from the image forming apparatus A, the control means 70 moves the tray means 25 to the lowermost sheet take-out position to prepare for taking out the sheet from the apparatus.

  In particular, by using a wrapping belt as the guide means 30 described above, the inclination angle of the wrapping belt with respect to the horizontal plane passing through the sheet discharge port is an angle as shown in the figure as the size of the stored sheet increases as shown in FIG. From β, the angle α (α << β) gradually becomes gentle. For this reason, the leading end of the sheet that is close to the sheet discharge port and has a strong waist can be forcibly guided to the aligning means 29. On the other hand, in the state that the sheet is far from the sheet discharge port and the sheet is easily buckled. The leading end of the sheet can be guided to the aligning means 29 softly. As a result, alignment suitable for the sheet is possible and the sheet can be securely stored.

1 is an overall configuration diagram of an image forming apparatus including a sheet stacking apparatus according to the present invention. FIG. 2 is an explanatory diagram of the structure of a sheet storage unit of the sheet stacking apparatus in the apparatus of FIG. 1. The detailed structure of the sheet | seat storage part in the apparatus of FIG. 1 is shown, (a) is the principal part explanatory drawing, (b) is a perspective explanatory drawing. FIG. 4 is a perspective explanatory view showing a detailed structure of a sheet storage unit in the apparatus of FIG. 1 and different from FIG. Explanatory drawing of the tray raising / lowering mechanism in the apparatus of FIG. FIG. 3 is an explanatory diagram of the structure of sheet side alignment means in the apparatus of FIG. 1. 2A and 2B are explanatory diagrams of a paper pressing unit in the apparatus of FIG. 1, in which FIG. 1A shows a state where a sheet side edge is pressed and held, FIG. 1B shows a state where a sheet is at a retracted position (home position); c) shows an overall configuration diagram. FIG. 5 is a configuration explanatory view of a sheet rear end pressing unit. FIGS. 2A and 2B are explanatory diagrams of a sheet carry-out operation in the apparatus of FIG. 1, in which FIG. 1A shows a state in which the leading end of the sheet has reached the guide belt, and FIG. FIGS. 2A and 2B are explanatory diagrams of a sheet carry-out operation in the apparatus of FIG. 1, in which FIG. 1A shows a state in which the sheet leading edge has reached the alignment rotating body, and FIG. The schematic diagram which showed the inclination-angle of the guide means according to sheet | seat size.

Explanation of symbols

A Image forming apparatus B Sheet stacking apparatus 21 Sheet carry-in path 22b Paper discharge port 25 Tray means (tray)
26 device frame 26a rear end regulating member 26b guide rail 28 upper unit 28a unit frame 28b holding guide 28c shaft 28v unit moving belt 29 aligning means 29a aligning rotating body 29b transmission belt 29c rotating shaft 29d bracket 29e backup member (bottom wall)
30 Guide means (winding belt) (guide belt)
33 Seat leading edge regulating means 33a Fixed stopper piece 33b Movable stopper piece 30P Entraining pulley 30t Tension spring 54 Seat side alignment means Pr Rack gear Pn Pinion Se1 Paper discharge sensor M1 Unit moving motor M2 Stopper motor M3 Lifting motor M4 Width-adjusting motor M6 Vertical movement Motor M8 drive motor

Claims (11)

A paper discharge port for sequentially carrying out the sheets;
Tray means for stacking and storing sheets arranged in a step on the downstream side of the discharge port;
A front end restricting means disposed at the front end of the tray means for restricting the position by abutting the front end of the sheet from the discharge port;
Aligning means for transferring the leading edge of the sheet sent from the discharge port onto the tray means toward the leading edge regulating means;
An upper unit disposed above the tray means and mounted with the tip restricting means and the aligning means;
With
The tip restricting means is provided so as to hang from the upper unit to the tray means,
The aligning means is constituted by an aligning rotating body that engages with the leading end of the sheet stacked on the tray means and abuts and aligns with the leading end regulating means,
The aligning rotator includes a belt member that guides the sheet leading end from the sheet discharge port onto the tray means,
The sheet stacking apparatus, wherein the upper unit is configured to be movable in accordance with the length of the sheet in the conveyance direction from the sheet discharge port. The alignment rotating body is either (1) a belt member that is stretched between a pair of pulleys and has one end engaged with a sheet on the tray means, or (2) a roller member positioned on the tray means and the roller member 2. The sheet accumulating apparatus according to claim 1, wherein the belt unit or a driving means for driving the transmission belt is mounted on the upper unit. 3. The sheet stacking apparatus according to claim 2, wherein the belt member or the roller member is attached to the upper unit so as to be movable up and down in accordance with a stacking amount of sheets stacked on the tray unit. 4. The pressing unit according to claim 1, wherein the upper unit is provided with a pressing guide member that is disposed between the aligning rotating body and the leading end restricting unit and prevents the sheet from curling up. 5. The sheet stacking device according to item. Between the discharge port and the aligning rotator, there is provided guide means for guiding the sheet upper surface from the discharge port to the aligning rotator,
The sheet accumulating apparatus according to any one of claims 1 to 4, wherein the guide means is configured to be expandable and contractable as the upper unit moves. The belt member is composed of a belt-like belt,
The belt-like belt is configured such that one end on the paper discharge port side is rotatably supported by the upper unit, and the tip on the tray means side is configured to be movable up and down.
6. The sheet stacking apparatus according to claim 5, wherein the tray unit is configured to descend downward from the sheet discharge port in accordance with a sheet stacking amount. A paper discharge conveying means for carrying out the sheet is disposed at the paper discharge port,
7. The alignment rotating body imparts to the sheet a conveyance speed that is lower than the conveyance speed at which the paper discharge conveyance means acts on the sheet, and curves the trailing edge of the sheet by the speed difference. The sheet stacking apparatus according to any one of the above. The discharge port is provided with a sensor for detecting the leading edge of the sheet,
The control means for controlling the aligning means starts and / or stops the rotation of the aligning rotator based on information that the sheet has reached the discharge port and length information in the sheet conveyance direction. The sheet stacking apparatus according to any one of claims 1 to 7. The control means obtains information that the sheet has reached the paper discharge port from a sensor disposed at the paper discharge port, and the sheet conveyance direction length information is an image forming apparatus disposed on the upstream side of the paper discharge port. The sheet accumulating apparatus according to claim 8, wherein the sheet accumulating apparatus is obtained from an external apparatus such as the above. The control means for controlling the aligning means decelerates at a lower speed than the speed at which the sheet trailing edge is carried out from the discharge outlet immediately before the leading edge of the sheet from the discharge outlet reaches the leading edge regulating means. The sheet stacking apparatus according to any one of claims 1 to 9. An image forming apparatus including an image forming unit that forms an image on a sheet;
A sheet stacking apparatus for stacking and storing sheets from the image forming apparatus;
An image forming system comprising: the sheet stacking apparatus having the configuration according to any one of claims 1 to 10.

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