JP2008094582A - Sheet stacking device and image forming device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To guide a sheet from a delivery port into a sheet conveyance means above a tray securely and stack the sheets dropping from the conveyance means on the tray in order. <P>SOLUTION: This sheet stacking device is provided with a tray means for stacking and storing the sheets from the delivery port, a tray elevating means for elevating and lowering the tray means vertically, the sheet conveyance means arranged above the tray means to hold the sheet from the delivery port and convey it onto the downstream side, a sheet tip regulation means for dropping the sheet fed by the sheet conveyance means on the tray means and storing it by regulating butting of a tip of the sheet, an air blowing means provided in the delivery port to jet air to the sheet toward the sheet conveyance means, and a control means for controlling the air blowing means. The control means controls the air blowing means in the following way: (1) air is blown until a tip of the sheet reaches the sheet tip regulation means, (2) air blowing is stopped after the tip of the sheet reaches the sheet tip regulation means, and (3) air is blown after the sheet drops on the tray means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet stacking apparatus that stacks and stores sheets sequentially delivered from an image forming apparatus or the like onto a tray unit from a sheet discharge port, and relates to an improvement in a sheet stacking mechanism that stacks large capacity sheets on a tray in an orderly manner.

  In general, this type of sheet stacking apparatus is widely known as an apparatus for stacking and storing sheets carried out from an image forming apparatus such as a printing machine or a copying machine on a tray unit disposed below a sheet discharge port. An apparatus for accumulating large-capacity sheets that are continuously carried out moves the tray means up and down according to the stacking amount.

Thus, when a sheet carried out from an image forming apparatus or the like is stacked on the tray, the sheet curls and is discharged above the tray when the sheet is carried out at high speed with heat (for example, heating at the time of image fixing). May be loaded unevenly. Conventionally, in order to prevent such jamming due to curling of sheets or uneven stacking on a tray, it has been proposed to provide a blowing means as disclosed in Patent Document 1, for example. This document discloses an apparatus that forms an air flow above a sheet and discharges it above the tray when the sheet conveyed by the vacuum belt is carried out to the tray.
Further, Patent Document 2 includes a blower mechanism that forms an air flow between a sheet sent from the rear end side (upstream side of the tray) of the tray and the tray, and scatters the distant above the tray in the same manner as Document 1. It is gaiji. In addition, it is easily understood that the air blowing mechanism of each of the above documents has an effect of cooling the heated sheet and preventing its curling.
Japanese Patent Laying-Open No. 2004-43113 (FIG. 3) JP 2004-217334 A (FIGS. 2 and 4)

  As described above, it is widely known that the sheet discharged from the inlet end of the tray is provided with a blower mechanism at the paper discharge port and scattered to the front end side of the far tray as in the above-mentioned patent document. However, such a method of carrying out the sheets by the air flow cannot orderly store the sheets on the tray. The present invention solves the following problems in an apparatus that conveys a sheet from a sheet discharge outlet toward the other end of the tray from the inlet end of the tray by a sheet conveying means disposed above the tray. When the front end of the sheet carried out from the paper discharge port is nipped or adsorbed to the conveying means such as a vacuum belt or gripper belt, if the front end of the sheet is curled due to heat or the like, the sheet cannot be held and the sheet is removed from the conveying means. There is a problem of being scattered and loaded on the tray. Therefore, when a blower mechanism is arranged at the paper discharge port and the sheet from the paper discharge port is guided to the sheet conveying means side by the air flow, the sheet dropped from the conveying means is scattered by this air flow and loaded on the tray. A new problem has arisen in which the sheet is moved in a collapsed state under the influence of airflow.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a simple sheet stacking apparatus that can reliably guide a sheet from a sheet discharge port to a sheet conveying means above the tray and can orderly stack sheets falling from the conveying means on the tray. The main challenge is to provide a simple structure at low cost.
Furthermore, the present invention provides a sheet stacking apparatus capable of unloading and aligning a sheet from a sheet discharge outlet to a predetermined position above the tray, dropping and aligning the sheet on the tray, and stacking the sheet on the tray at high speed, and an image forming apparatus including the sheet stacking apparatus. Providing a device is an issue.

  To achieve the above object, the present invention employs the following configuration. A sheet discharge port for sequentially carrying out the sheets, a tray unit arranged to form a step below the sheet discharge port, for stacking and storing sheets from the sheet discharge port, and the tray unit vertically below the sheet discharge port The tray lifting and lowering means that moves up and down, the sheet conveying means that is disposed above the tray means and holds the sheet from the sheet discharge port and conveys it to the downstream side, and the leading edge of the sheet sent by the sheet conveying means is regulated to abut The sheet leading edge regulating means for dropping and storing the sheet on the tray means, the blowing means provided at the sheet discharge port for injecting air toward the sheet conveying means, and the control means for the blowing means Prepare. The air blowing means is arranged at the paper discharge port so as to blow air toward the sheet conveying means, the control means is arranged to blow the air blowing means, and (1) until the sheet leading edge reaches the sheet leading edge regulating means. Air is blown, (2) the blower is stopped after the leading edge of the sheet reaches the leading edge restricting means, and (3) the blower is controlled to blow after the sheet has fallen onto the tray means.

  The sheet conveying unit includes a transfer belt that nips or sucks a sheet from the sheet discharge port and conveys the sheet to the downstream side, and the blower unit includes air that guides the sheet leading end from the sheet discharge port to the transfer belt. The transfer belt is disposed above the paper discharge port and toward the tip of the tray means. The air jet port is disposed so as to form an air flow from below the paper discharge port toward the transfer belt to guide the sheet from the paper discharge port to the transfer belt.

  The sheet conveying means includes a transfer belt that nips or sucks a sheet from the sheet discharge port and conveys the sheet downstream, and a sheet pressing means that strikes a sheet that falls from the transfer belt onto the tray means. . Therefore, when the sheet from the transfer belt is stored on the tray unit by the sheet pressing unit, the control unit of the blowing unit stops the blowing of the blowing unit. The sheet pressing means is constituted by a pressing piece that is arranged above the sheet discharge port and strikes the rear end of the sheet fed by the transfer belt toward the tray means.

  Further, the tray means is provided with a paper pressing means for pressing the sheets stacked on the tray means, and the paper pressing means is a pressing position for pressing the uppermost sheet on the tray means and a retreat separated from the uppermost sheet. It is configured to be movable between positions. The control means of the air blowing means is configured to stop the air blowing of the air blowing means when the paper pressing means is in the retracted position.

In addition, the present invention can achieve the above-described problem also by the following configuration. A sheet discharge port for sequentially carrying out the sheets, a tray unit arranged to form a step below the sheet discharge port and stacking and storing sheets from the sheet discharge port, and a sheet unit disposed above the tray unit A sheet conveying unit that holds the sheet from the opening and conveys the sheet to the downstream side, a sheet leading end regulating unit that abuts and regulates the leading end of the sheet sent by the sheet conveying unit, and stores the sheet on the tray unit by dropping, A sheet pressing means for striking a sheet falling on the tray means by the sheet leading edge regulating means, a paper pressing means movable between a pressing position for pressing the uppermost sheet on the tray means and a retreat position; A blower unit that is provided at a paper discharge port and injects air onto the sheet toward the sheet conveying unit, a sheet pressing unit, a paper pressing unit, and a control unit that controls the blowing unit.
The air blowing means is arranged at the paper discharge port so as to blow air toward the sheet conveying means, the control means is the air blowing means, and (1) the leading edge of the sheet sent by the sheet conveying means is the sheet. Air is blown until the leading edge restricting means is reached, and the paper pressing means is held in an operating position for pressing down the uppermost sheet on the tray means. (2) After the sheet leading edge reaches the sheet leading edge restricting means, the air is blown. At the same time, the sheet pressing means is moved to the retracted position, and the sheet pressing means strikes the sheet toward the tray means. (3) After the sheet falls on the tray means, the air blowing is stopped. The paper pressing means is configured to move to the operating position.

  Furthermore, an image forming apparatus according to the present invention includes a sheet stacking apparatus having a sheet discharge unit that guides a sheet from the image forming apparatus to a sheet discharge port, and a tray unit that stacks and stores the sheet from the sheet discharge port. The sheet stacking apparatus has the above-described configuration.

  The present invention provides an air blower for injecting air to the sheet toward the sheet conveying means in the stacking apparatus provided with the sheet conveying means for holding and conveying the sheet from the discharge outlet to the downstream side, (1) Air is blown until the sheet leading edge reaches the sheet leading edge regulating means, (2) air blowing is stopped after the sheet leading edge reaches the sheet leading edge regulating means, and (3) the sheet is Since it is controlled so as to blow air after dropping on the tray means, the following effects are produced. The sheet from the paper discharge port is guided to the sheet conveying means by the air flow from the air blowing means, and even a curled sheet is securely held by the sheet conveying means. Further, the sheet transferred to a predetermined position above the tray by the conveying means is dropped and accumulated on the tray in a correct posture without receiving the air flow from the blowing means.

  Further, the sheet conveying means is provided with a sheet pressing means for striking the sheet toward the tray means, and the sheets are stacked and stored on the tray in order without being affected by the air flow remaining between the conveying means and the tray means. I can do it. Further, by providing the tray means with paper pressing means for pressing and supporting the sheets on the tray, there is an effect that the stacked sheets are not scattered by the air flow sent from the air blowing means, or the posture thereof is not destroyed. .

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 is an overall view of an image forming system provided with a sheet stacking apparatus according to the present invention, and FIG. 2 is a configuration diagram of a main part of the sheet stacking apparatus.

[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 paper 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 paper 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 manner are sequentially carried out from the paper discharge port 3 (hereinafter referred to as “main body discharge port”). 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, a tray unit 25, a sheet conveying unit 28, and a sheet leading end regulating unit 33 arranged in a suitably shaped housing 20 (see FIG. 1). Then, the sheet is sent from the sheet carry-in path 21 to the sheet discharge port 23, the sheet is conveyed to the front end side of the tray by the sheet conveying unit 28, and the sheet is abutted against the sheet leading end regulating unit 33 to be separated from the sheet conveying unit 28. The tray means 25 is dropped and stored.

[Sheet carry-in route]
The sheet carry-in path 21 includes a conveyance guide having a sheet receiving port 22 and a sheet discharge port 23, and a sheet discharge unit 24 that conveys the sheet is provided in the sheet carry-in path 21. As shown in FIG. 2, the paper discharge unit 24 includes a driving roller 24 a and a driven roller 24 b (or a driven belt), and carries a sheet from the receiving port 22 to a paper discharge port 23. The paper discharge means 24 is provided with a next blower means 64, which simultaneously cools the sheet in the path and guides the sheet from the paper discharge port 23 to the sheet conveying means 28, which will be described later. Yes. S1 in the drawing is a paper discharge sensor for detecting the leading edge and the trailing edge of the sheet.

[Blower means]
The air blowing means 64 is provided in the sheet carry-in path 21 and includes a duct 65 having a jet outlet 64 a in the vicinity of the driving roller 24 a and a blower fan 66 built in the base end portion of the duct 65. The jet port 64a is disposed at a position where the sheet sent from the driving roller 24a is guided to the sheet conveying means 28 described later.

[Sheet conveying means]
A sheet conveying means 28 is provided above the downstream side of the paper discharge port 23. The sheet conveying means 28 is constituted by a grip belt or a vacuum belt for nipping the sheet, and conveys the sheet from the sheet discharge port 23 to the front end side of the tray by nip or suction. This is because when the sheet from the sheet discharge port 23 is directly carried out onto the tray, it comes into contact with the sheet on the tray and causes a sheet discharge failure (jam), and the sheet discharge speed is limited by the frictional resistance of the sheet. Accordingly, the sheet conveying means 28 transports the sheet from the paper discharge port 23 to the front end of the tray at the same speed as the speed at which the paper discharge means 24 carries it out, and the sheets are dropped and accumulated while the entire sheet is moved onto the tray. It is. Therefore, the sheet conveying means 28 is constituted by a vacuum belt that sucks the sheet or a grip belt that nips the leading end of the sheet.

  The structure of the latter grip belt will be described. A pair of pulleys 29a and 29b are provided on the apparatus frame 26 above a tray means 25 described later, and a transfer belt 30 is stretched between the pulleys. The transfer belt 30 is provided with a gripper member 27. The gripper member 27 has a nip piece 27a that engages with the front end of the sheet so as to grasp the front end of the sheet from the discharge outlet 23 and guide it to a predetermined unloading position Ep (see FIG. 2). The transfer belt 30 is integrally provided so as to move at the same speed as the other sheet. A driving motor M1 is connected to the pulley 29a and rotates clockwise in FIG. Therefore, when the transfer belt 30 is stopped with the gripper member 27 facing the paper discharge port 23 and the sheet is unloaded from the paper discharge port 23, the leading edge of the sheet enters between the nip piece 27a and the belt surface, and the nip piece 27a The leading edge of the sheet is gripped by the elastic force.

[Sheet tip regulating means]
At the carry-out position Ep of the sheet conveying means 28, a sheet leading edge regulating means 33 is provided. The sheet leading edge regulating means 33 is arranged above the tray means 25 along with the transfer belt 30. A stopper piece 33 a that abuts against the leading edge of the sheet transferred by the transfer belt 30 and separates from the sheet conveying means 28 is provided. A plurality of the stopper pieces 33a are arranged in the width direction of the sheet (conveying orthogonal direction) and are configured to move back and forth in the conveying direction according to the sheet size as shown in FIG. That is, the sheet front end restricting means 33 (hereinafter referred to as “stopper unit”) is supported by the apparatus frame 26 on a guide rail (not shown) so as to be movable forward and backward in the transport direction (left and right direction in FIG. 2). The stopper unit 33 is connected to a position adjustment belt (endless belt or the like) stretched in the left-right direction in FIG. 2, and this belt is moved by the position adjustment motor M2 (not shown) in the left-right direction in FIG. It has become.

  Although not shown, the stopper unit 33 is provided with a detection sensor Sp1 for detecting a paper surface level on the tray means 25, which will be described later. The tray means 25 detects that a predetermined amount of sheets are stacked on the tray. The details will be described later.

[Seat side alignment means]
As described above, the sheet from the paper discharge port 23 is conveyed to the front end side of the tray by the sheet conveying unit 28, and is peeled off from the sheet conveying unit 28 by the sheet front end regulating unit (stopper unit) 33 and falls onto the tray 25. In this process, the sheet is aligned in the conveyance orthogonal direction by the sheet side aligning means 54 and is stored in alignment on the tray. For this reason, sheet side alignment means 54 including alignment members 54a and 54b is provided on the side edges (around FIG. 2) of the sheet conveyed by the sheet conveyance means 28. As shown in FIG. 2, the rear side alignment member 54 b and the front side alignment member 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 the alignment members 54a and 54b (hereinafter collectively referred to as “alignment member 54”) are supported by the shaft member 54c and moved in the left-right direction in FIG. 3A.

  The illustrated alignment member 54 is movable to an engagement position X (see FIG. 3A) for engaging with the sheet side edge, a standby position Y slightly separated from the sheet side edge, and a retracted position Z sufficiently separated from the sheet side edge. The shaft member 54c is fitted and supported. The alignment member 54 is connected to a pair of left and right shift levers 56 connected to the width adjusting motor M4, and both levers are engaged with a pinion M4p of the width adjusting motor M4. Accordingly, the alignment member 54 moves in accordance with the width size of the sheet by the rotation of the pinion M4p. That is, the front side / rear side alignment members 54a and 54b are moved to a position suitable for the sheet width size 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 are engaged. It will reciprocate by the forward / reverse rotation of the pinion pM4 with the engaging position (operating position) X to be matched. Further, the aligning member 54 is moved by the width adjusting motor M4 to the retracted position Z sufficiently separated from the sheet side edge.

Simultaneously with the movement to the retracted position Z due to the rotation of the width adjusting motor M4, the front-side alignment member 54a is configured such that the leading end hanging piece 54a 'hanging down to the tray 25 side bends to the retracted position Z shown in FIG. The structure is such that the leading end hanging piece 54a 'is pivotally supported at the base end portion and is urged to the engagement position (operating position) X and standby position Y shown in FIG. . A cam piece 55a is provided on the tip depending piece 54a ', and a protruding lever 55b formed on the device frame 26 abuts against the cam piece 55a.
Accordingly, when the leading end hanging piece 54a ′ of the front side alignment member 54a moves from the standby position Y to the retracted position Z, the cam piece 55a hits the protruding lever 55b of the apparatus frame 26 and bends to the state shown in the solid line in the figure. In this way, the retracted position Z of the pair of alignment members 54 is a position separated from the sheet side edge in the sheet conveyance orthogonal direction, and at least the front-side alignment member 54a positioned on the side for taking out the sheets on the tray to the outside is the tray. It swings upwards and retracts. Therefore, when the tray 25 is taken out together with the sheets stacked in the arrow direction (the apparatus front side), the front side alignment member 54a is retracted above the tray.

  Next, the above-described front side alignment member 54a may have a structure shown in FIG. 3B. A solid line is shown by connecting an electromagnetic solenoid 57 to a tip drooping piece 54a 'pivotally supported on the front side alignment member 54a and suspending the tip drooping piece 54a' against the biasing spring by the electromagnetic solenoid 57. It can be moved to the retreat position. The electromagnetic solenoid 57 is operated by an instruction signal for lowering a tray lifting / lowering means 31 (described later) to an attachment / detachment position (lowermost position), for example.

  Next, control of the above-mentioned width adjusting motor M4 will be described. The width adjusting motor M4 constitutes drive means for moving the sheet side aligning means 54 between the engagement position (actuation position) X and the retracted position Z. As will be described later, (1) Tray A control signal for lowering the elevating means 31, or (2) the detection sensor S3 of the carrier means 40 positioned at the tray attaching / detaching position, or (3) an opening / closing door 50a for positioning the carrier means 40 at the tray attaching / detaching position, The seat side aligning means 54 is configured to move from the engagement position to the retracted position in response to any signal from a detection sensor (door opening / closing sensor S5 described later) that detects the opening operation of 50b.

[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 means 25 together with the sheet side alignment means 54. As shown in FIG. 4, the sheet trailing edge pressing means 58 is disposed on the downstream upper side of the sheet discharge outlet 23, and a flat plate-like hitting piece 58a that strikes the sheet trailing edge from the sheet discharge outlet 23 on the lower tray means 25. It has. 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. The drive lever 60 swings at a predetermined angle by forward and reverse rotation of the drive motor M5. The hitting piece 58a connected to the drive lever 60 has a solid line and a chain line shown in FIG. Will move up and down. Therefore, the sheet that is peeled off from the sheet conveying means 28 by the sheet leading edge regulating means (stopper unit) 33 and dropped onto the tray means 25 is tapped down at the rear end thereof by the tapping piece 58a and stored on the tray. It becomes.

[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 arm 31 is provided with guide rails 32a and 32b on the apparatus frame 26, and is guided along the guide rail in the stacking direction (vertical direction in FIG. 5) so as to be movable up and down. The elevating arms 31 a and 31 b are suspended by a pulling member 37 such as a wire or belt that is stretched over a suspension pulley 36 fixed to the apparatus frame 26, and the illustrated pulling wire is connected to a take-up pulley 38. A lifting motor M3 is connected to the winding pulley 38. Therefore, the elevating arm 31 is supported by the guide rails 32a and 32b of the apparatus frame 26, and is moved up and down by the elevating motor M3. The tray 25 is mounted on the lifting arms 31a and 31b, and is moved up and down according to the stacking amount below the paper discharge port 23. The elevating arms 31a and 31b are provided with a rear end regulating member 34 for regulating the rear end of the sheet. The rear end of the sheet from the sheet discharge port 23 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.

[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 supporting the stacked sheets. The sheets stacked on the tray 25 are provided with a pair of left and right paper pressing members 61a and 61b (hereinafter collectively referred to as “paper pressing means 61”) for pressing and supporting the sheet side edge orthogonal to the paper discharge direction. When the sheet falls, the pressing means 61 retracts from the tray 25 and presses the uppermost sheet after the sheet is dropped and stored. For this reason, the illustrated paper pressing means 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 62c. The arm 63 connected to the vertical movement motor M6 is fitted to the paper touch piece 62a. . Accordingly, when the vertical movement motor M6 is driven in the direction of the arrow in FIG. 6C, 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.

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

[Installation structure]
The installation structure of the above-described lifting arms 31a and 31b will be described with reference to FIG. 7. The guide rails 32a and 32b are fixedly supported by an installation frame 39 that supports the housing 20 and the apparatus frame 26. This installation frame 39 is formed of a U-shaped frame, and the front side of the apparatus, the front side of FIG. 1 (the left front side of FIG. 7) is opened, and a pair of left and right side frames 39a and 39b are connected by a connecting frame 39c on the back side. Fixed and configured. A carrier means (transport cart) 40, which will be described later, can be carried in from the front side of the apparatus. The pair of left and right side frames 39a and 39b are provided with casters 39d to support the overall weight of the sheet stacking apparatus B. The installation frame 39 is provided with a connecting portion for carrier means 40 to be described later and a stopper means for preventing the carrier means 40 from being connected.

[Career means]
Next, the carrier means 40 will be described with reference to FIG. 7. The tray 25 is detachably mounted on the tray lifting / lowering means (lifting / lowering arm) 31, and the tray 25 is taken over by the carrier means 40 installed under the lifting / lowering member. It is mounted and carried out of the device. Therefore, the carrier means 40 includes a carriage frame 41 and an operation handle 42 fixed to the carriage frame 41. The carriage frame 41 is configured in a U shape by integrally fixing a pair of left and right fork-like arm members 41a and 41b (fork members; hereinafter the same) and a connecting arm 41c. An operating handle 42 for pushing is fixed to the connecting arm 41c, and wheels 43 are attached to the left and right arm members 41a and 41b. Accordingly, by manually pressing the operation handle 42, the tray 25 on which the sheets are stacked can be mounted on the arm members 41a and 41b and transported.

[Carrier means positioning set]
The arm members 41 a and 41 b of the carrier means 40 are guided between the pair of left and right side frames 39 a and 39 b of the installation frame 39 and guided into the housing 20. That is, the outer dimension L1 of the arm members 41a and 41b substantially coincides with the inner dimension L2 of the side frames 39a and 39b on the apparatus frame side (L1 = L2), and is guided between the side frames so as to enter the housing 20. It has become. Accordingly, the side frames 39 a and 39 b of the installation frame 39 constitute a guide member for guiding the carrier means 40 into the housing 20. The left and right arms 41a and 41b are formed so that the former is wide (L3) and the latter is narrow (L4) so that the elevating arms 31a and 31b are located inside, and L3> L4.

  Therefore, a positioning recess (positioning member) 44 is provided in the connecting frame 39c of the installation frame 39, and protrusions (not shown) formed on the arm members 41a and 41b of the carrier means 40 are fitted. Yes. A magnet catch 44a is embedded in the positioning recess 44, and at the same time, a detection sensor S3 including a magnetic sensor (lead sensor) is built in the catch. Accordingly, the carrier means 40 is guided by the side frames 39a and 39b of the installation frame 39, and is positioned by being fitted into the positioning recess 44, and is held by the magnet catch 44a. The detection sensor S3 detects whether or not the carrier means 40 is mounted at a predetermined position, and the lifting arms 31a and 31b positioned above are lowered.

  The sheet discharge operation in the above-described apparatus will be described. For example, the control unit 70 of the sheet stacking apparatus B drives and rotates the sheet discharge unit 24 when receiving a discharge instruction signal from the image forming apparatus A, for example. . 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. At this time, since the sheet conveying means 28 is waiting at a position where the gripper member 27 faces the paper discharge port 23, the leading edge of the sheet is sandwiched between the nip pieces 27a and held by the transfer belt 30 by its elasticity. When the sheet conveying means 28 is constituted by a vacuum belt, it is sucked and held by this belt. Next, the control unit 70 rotates and drives the sheet conveying unit 28 at the same speed as that of the sheet discharging unit 24, and performs a “sheet discharging operation” in which the sheet is conveyed to the front end side of the tray. When the leading edge of the sheet fed by the sheet conveying means 28 abuts against the stopper piece 33a of the sheet leading edge regulating means 33, the sheet is peeled off from the transfer belt 30. At this time, the trailing edge of the sheet is carried out from the paper discharge port 23 to the tray side. Because of this, the sheet falls, “sheet dropping operation”. Therefore, when the control means 70 moves the alignment members 54a and 54b of the sheet side alignment means 54 waiting in advance to the standby position Y to the engagement position X, the sheet is hit by the alignment members 54a and 54b at the side edges, and the width adjustment alignment is performed. "Sheet width direction alignment".

  The control means 70 rotates the drive motor M5 of the sheet trailing edge pressing means 58 and swings the drive lever 60 in the clockwise direction in FIG. 4 before and after the alignment of the alignment members 54a and 54b. Then, the “sheet pressing operation” in which the hitting piece 58a vigorously hits the rear end of the sheet downward. Prior to this operation, the control means 70 has moved the paper contact piece 62a of the paper pressing means 61 to the retracted position. This movement to the retreat position is a “paper retraction member retreat operation” in which the paper touch piece 62a is moved to retreat in FIG.

  Therefore, the sheet from the sheet discharge port 23 is conveyed to the front end of the tray by the sheet conveying means 28, separated from the sheet conveying means 28, and dropped to the tray side. Fall. Next, the control means 70 operates the vertical movement motor M6 at the timing when the sheet is stored on the tray and returns the paper touch piece 62a at the retracted position to the operating position for pressing the sheet on the tray.

  By repeating the above-described operation, the sheets sent to the paper discharge outlet 23 are stacked and stored on the tray 25. When the paper level detection 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. When this fullness is detected or in response to a job end signal from the image forming apparatus A, the control unit 70 activates the width adjusting motor M4 to move the sheet side alignment unit 54 to the retreat position Z described above. Then, the rear side alignment member 54b is retracted to a position sufficiently away from the sheet side edge, and the front side alignment member 54a is sufficiently separated from the sheet side edge, and the leading end hanging piece 54a ′ at the lower end thereof swings upwards of the tray. Then retreat. For this reason, when taking out the sheet | seat on the tray 25, there is no possibility that the sheet | seat of an upper layer part may collide with the front side alignment member 54a, and may cause load collapse.

  Therefore, the present invention is characterized in that the control means 70 for controlling the air blowing means 64 is configured as follows. (1) First, air is blown when the sheet is nipped and held by the sheet conveying means 28 from the paper discharge port 23 and until the leading edge of the sheet sent by the sheet conveying means 28 reaches the sheet leading edge regulating means 33. At the same time, the control means 70 holds the paper pressing means 61 at the operating position for pressing down the uppermost sheet on the tray means 25 (state shown in FIG. 9A). (2) Next, the control means 70 stops air blowing after the sheet leading edge reaches the sheet leading edge regulating means 33. At the same time, the sheet pressing means 61 is moved to the retracted position, and the sheet trailing edge pressing means 58 strikes the sheet toward the tray means 25 (state shown in FIG. 9B). (3) Then, after the sheet falls on the tray means 25, the control means 70 moves the paper pressing means 61 to the operating position in a state where the blowing is stopped (state of FIG. 9C).

  With this configuration, even in the state of FIG. 9A, even if a thin paper sheet is curled at the leading edge, the leading edge of the sheet is reliably niped or adsorbed by the sheet conveying means 28 by the action of air blowing from the blowing means 64 and conveyed downstream. Is done. Accordingly, the leading edge of the sheet curls downward and is not held by the sheet conveying means 28, and does not cause a paper jam on the tray. The sheet holding the leading edge receives air from the blowing means 64 until the leading edge reaches the sheet leading edge regulating means 33, and the high temperature sheet is cooled. Therefore, the sheet is not curled by its own heat after being accumulated on the tray.

  In the state of FIG. 9B, the sheet is peeled off from the sheet conveying means 28 and falls onto the tray 25. At that time, the air blowing means 64 stops air blowing, so the sheet is surely prevented from scattering. The sheet is aligned by the side aligning means 54 and is quickly dropped and accumulated on the tray 25 by the sheet trailing edge pressing means 58.

  In the state shown in FIG. 9C, sheets are stacked on the tray 25, and the blowing unit 64 stops blowing until the sheet pressing unit 61 presses and supports the sheets. Therefore, the sheets stacked on the tray are scattered. Or the posture does not collapse. Thereafter, the control means 70 operates the air blowing means 64 again to resume the air blowing, and prepares for the subsequent sheet carry-out.

[Tray lifting operation]
Next, the operation of handing over the tray means 25 between the carrier means 40 and the tray lifting / lowering means 31 will be described. The device housing 20 is provided with opening / closing doors 50a, 50b on the front side of the device (front side in FIG. 1), and the opening / closing door 50a, 50b is provided with a door opening / closing sensor Sp5. Therefore, the control means 70 for controlling the lift motor M3 raises the tray 25 mounted on the lift arms 31a and 31b to a position where the paper surface level detection sensor Sp1 detects by the initialization operation when the apparatus power is turned on. Then, the lift arms 31a and 31b are lowered by a predetermined amount in response to the detection signal of the level detection sensor Sp1. Then, a preset step D (see FIG. 10A) is formed between the discharge outlet 23 and the tray 25, and sheets from the discharge outlet 23 are stacked and stored on the tray.

  When a predetermined amount of sheets are stacked on the tray, the paper level detection sensor Sp1 detects this, and the control means 70 rotates the elevating motor M3 so as to lower the elevating arms 31a and 31b by a predetermined amount. In this way, when sheets are stacked on the tray and the stacking amount reaches a predetermined amount, the control means 70 lowers the lifting arms 31a and 31b by a predetermined amount by a signal from the paper surface level detection sensor Sp1, and according to the sheet stacking amount. Gradually descend. When the elevating arms 31a and 31b reach the maximum loading position, the maximum loading position detection sensor Sp3 detects this, and at the same time as issuing a “full detection signal”, the apparatus is stopped.

  Next, when the user opens the open / close doors 50a and 50b by the full detection signal or the job end signal, the control means 70 detects this by the door open / close sensor S5 and safely stops the apparatus. In this state, the elevating arms 31a and 31b are held at the full position or above the positions. When the user enters the carrier means 40 into the apparatus, the carriage frame 41 of the carrier means 40 is guided into the apparatus by guiding the arm members 41a and 41b to the side frames 39a and 39b of the installation frame 39. When a protrusion (not shown) of the carrier means 40 is fitted into the positioning recess 44, the detection sensor S3 detects this. The control means 70 descends the lifting arms 31a and 31b toward the attachment / detachment position by a signal from the detection sensor S3, and stops the lifting motor M3 when the lower limit position detection sensor Sp4 is “ON”. At this time, the elevating arms 31a and 31b transfer the tray 25 to the arm members 41a and 41b of the carriage frame 41 in the state shown in FIG.

  As described above, according to the present invention, the sheet side aligning means that regulates and aligns the side edges of the sheets stacked on the tray is retracted to the retracted position away from the sheet side edges when the tray is lowered to take out the sheets. When the user takes out the sheet from the tray or when the tray is transferred to the carrier means 40 for transportation, the load does not collapse.

FIG. 1 is an overall view of an image forming system provided with a sheet stacking apparatus according to the present invention. The principal part block diagram of a sheet | seat stacking apparatus. FIG. 6 is an operation explanatory diagram of sheet size matching means. An embodiment different from FIG. 3A is shown. The operation | movement explanatory drawing of a sheet rear end pressing means. The structure explanatory view of tray raising and lowering means. 4A and 4B are explanatory diagrams of a paper pressing unit, in which FIG. 4A shows a state in which a sheet side edge is pressed and supported, FIG. 4B shows a state in a retracted position (home position), and FIG. Indicates. The installation structure of a tray raising / lowering means is shown. The whole perspective view of a carrier means. The operating state of the air blowing means and the paper pressing means until the sheet reaches the sheet leading edge regulating means is shown. The operating state of the blowing means and the sheet trailing edge pressing means after the sheet leading edge reaches the sheet leading edge regulating means is shown. The operating state of the air blowing means and the paper pressing means after the sheet falls on the tray means is shown. (A) (b) It is explanatory drawing of raising / lowering operation | movement of a tray means, and shows the state which a tray means stacks | stacks a sheet | seat.

Explanation of symbols

A Image forming apparatus B Sheet stacking apparatus 20 Housing 21 Sheet carry-in path 23 Paper discharge port 24 Paper discharge means 25 Tray means 28 Sheet conveying means 31 Tray elevating means 31a Elevating arm 31b Elevating arm 33 Sheet leading edge regulating means (stopper unit)
39 Installation frame 40 Carrier means 41a Arm member 41b Arm member 54 Sheet side aligning means 54a Front side aligning member 54a 'leading end hanging piece 54b Rear side aligning member 58 Sheet rear end pressing means 58a Tapping piece 60 Drive lever 61 Paper pressing means 61a Paper Holding member 61b Paper holding member 62a Paper touching piece 62b Cylinder cam 62c Inclined cam groove 62d Pin 64 Blowing means 64a Spout port 65 Duct 66 Blower fan 70 Control means M3 Lifting motor M4 Widening motor M4p Pinion M5 Drive motor M6 Vertical movement motor S3 Detection sensor S5 Door open / close sensor Spa Position sensor Sp1 Paper level detection sensor

Claims (7)

A paper discharge port for sequentially carrying out the sheets;
Tray means arranged to form a step below the paper discharge port and stacking and storing sheets from the paper discharge port;
Tray elevating means for elevating and lowering the tray means below the discharge port;
A sheet conveying means disposed above the tray means for holding the sheet from the sheet discharge port and conveying the sheet downstream;
A sheet front end restricting means for abutting and restricting the front end of the sheet sent by the sheet conveying means to drop and store the sheet on the tray means;
A blowing unit provided at the sheet discharge port for injecting air toward the sheet toward the sheet conveying unit;
Control means for the air blowing means;
In a sheet stacking apparatus comprising:
The air blowing means is arranged at the paper discharge port so as to blow air toward the sheet conveying means,
The control means controls the air blowing means.
(1) Blow until the sheet leading edge reaches the sheet leading edge regulating means,
(2) After the sheet leading edge reaches the sheet leading edge regulating means, the air blowing is stopped,
(3) After the sheet falls on the tray means, air is blown.
The sheet stacking apparatus characterized by controlling the blowing means as described above. The sheet conveying means includes a transfer belt that nips or sucks a sheet from the sheet discharge port and conveys the sheet downstream.
The air blowing means has an air jet port for guiding the leading edge of the sheet from the paper discharge port to the transfer belt,
The transfer belt is disposed above the paper discharge port toward the tip of the tray means,
2. The air jet port according to claim 1, wherein the air jet port is disposed so as to form an air flow from below the paper discharge port toward the transfer belt to guide a sheet from the paper discharge port to the transfer belt. The sheet stacking apparatus according to claim 1. The sheet conveying means includes
A transfer belt that nips or sucks a sheet from the sheet discharge port and conveys the sheet downstream;
Sheet pressing means for striking a sheet falling from the transfer belt onto the tray means;
Consisting of
2. The sheet stacking apparatus according to claim 1, wherein the control unit of the blowing unit stops blowing of the blowing unit when the sheet from the transfer belt is stored on the tray unit by the sheet pressing unit. . 4. The sheet pressing means comprises a pressing piece that is disposed above the sheet discharge port and strikes the rear end of the sheet fed by the transfer belt toward the tray means. Sheet collecting device. The tray means is provided with paper pressing means for pressing the sheets stacked on the tray means,
The paper pressing unit is configured to be movable between a pressing position for pressing the uppermost sheet on the tray unit and a retracted position spaced from the uppermost sheet.
5. The sheet stacking apparatus according to claim 1, wherein the control unit of the blowing unit stops blowing of the blowing unit when the paper pressing unit is in the retracted position. A paper discharge port for sequentially carrying out the sheets;
Tray means arranged to form a step below the paper discharge port and stacking and storing sheets from the paper discharge port;
A sheet conveying means disposed above the tray means for holding the sheet from the sheet discharge port and conveying the sheet downstream;
A sheet front end restricting means for abutting and restricting the front end of the sheet sent by the sheet conveying means to drop and store the sheet on the tray means;
Sheet pressing means for striking a sheet falling on the tray means by the sheet leading edge regulating means;
A paper pressing means movable between a pressing position for pressing the uppermost sheet on the tray means and a retracted position;
A blowing unit provided at the sheet discharge port for injecting air toward the sheet toward the sheet conveying unit;
Control means for controlling the sheet pressing means, the paper pressing means and the air blowing means;
With
The air blowing means is arranged at the paper discharge port so as to blow air toward the sheet conveying means,
The control means controls the air blowing means.
(1) Air is blown until the sheet leading edge sent by the sheet conveying means reaches the sheet leading edge regulating means, and the paper pressing means is held at an operating position for pressing down the uppermost sheet on the tray means,
(2) After the sheet leading edge reaches the sheet leading edge regulating means, the air blowing is stopped, the paper pressing means is moved to the retracted position, and the sheet pressing means strikes the sheet toward the tray means,
(3) The sheet stacking apparatus, wherein after the sheet falls on the tray means, the paper pressing means is moved to the operating position in a state where the blowing is stopped. An image forming apparatus for sequentially forming images on sheets;
A paper discharge unit for guiding the sheet from the image forming apparatus to a paper discharge port;
A tray stacking unit for stacking and storing sheets from the sheet discharge port;
Consisting of
An image forming apparatus comprising the sheet stacking apparatus according to any one of claims 1 to 6.

Images