JP2011088686A - Paper stacking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a smear of an image caused by the existence of the image over the whole paper or the narrowness of a paper space between ejecting paper sheets, and to prevent the stacking deterioration on stacking paper even if a paper ejecting tray is moved by a tray shift mechanism. <P>SOLUTION: When starting paper feeding processing, a paper ejecting motor is turned on, and a paper ejecting roller rotates (S1). A determination is made on whether or not thee paper feeding processing is finished (S2), and when it is not finished (No of S2), the paper is received (S3), and a determination is made on whether or not the rear end of the paper is detected (S4). When the rear end of the paper is detected (Yes of S4), a clutch is turned on (S5), and time measurement is started (S6), and a determination is made on whether or not a predetermined time passes (S7). When the predetermined time passes (Yes of S7), a tray shift request is confirmed (S8), and when there is a request (Yes of S8), tray shift operation is performed (S9), the clutch is turned off (S10). A determination is made again on whether or not the paper feeding processing is finished (S2), and when it is finished (Yes of S2), the paper ejecting motor is turned off (S11), and the paper feeding processing is finished. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet stacking apparatus that is provided in an image forming apparatus and stacks and sorts discharged sheets.

  2. Description of the Related Art Conventionally, there is known a paper stacking device that discharges and stacks paper on which an image has been formed by a copying machine or the like for each job. In such an apparatus, a paper return member is required to align the paper discharged to the paper discharge tray. However, there is a problem in that the image return member is scraped off because the sheet return member keeps rotating while contacting the same position with respect to the discharged sheet.

  Therefore, as a first conventional technique, Patent Document 1 discloses that the return member 3 and the drive unit (discharge motor 5) of the discharge means (discharge roller 1) are the same as shown in FIG. / A technique for reducing image smearing by stopping the driving source when the alignment is completed (stopping the return member 3 and the discharging means simultaneously) has already been disclosed.

  Further, as a second prior art, in Patent Document 2, the paper return member 3 as shown in FIGS. 10A and 10B can be moved by the solenoid 6 and the folder 7 to complete the discharge / alignment of the paper. Sometimes, a technique for reducing image contamination by moving the contact position between the return member 3 and the paper P to a region without an image (the end surface of the paper) has been disclosed. The return member 3 is in contact with the sheet even after the solenoid 6 is turned on when the sheet discharge tray 2 is shifted in a direction perpendicular to the transport direction in a sheet stacking apparatus having a tray shift mechanism. This is to prevent the stacked sheet bundle from collapsing.

  Further, as shown in FIGS. 11A and 11B as the third prior art, the return member 3 is movable, and when the discharge / alignment of the paper P is finished, the return member 3 is retracted. There is already known a technique for reducing image smear by making no contact with the paper P.

  Alternatively, as shown in FIG. 12 as the fourth prior art, when the return member 3 and the drive means (discharge motor 5 and return motor 8) of the discharge means are separated, the discharge / alignment of the paper is finished. In addition, a technique for reducing image contamination by stopping the return member 3 is already known.

  However, in the first conventional technique in the paper stacking apparatus having such a configuration, the discharge unit is stopped when the paper interval (interval between the paper and the next paper) that is continuously discharged is narrow. Therefore, there is a problem that the return member cannot be stopped and the image is stained.

  In the second prior art, when an image (toner) is formed on the entire surface of the sheet, that is, when there is an image on the end surface of the sheet, the return member scrapes the image on the end surface of the sheet. There was a problem that dirt was generated.

  In the third prior art, when the return member is retracted and is not in contact, the stackability is deteriorated, for example, the stacked sheet bundle is broken. That is, when the tray is shifted as described in Patent Document 2, if the return member is not brought into contact, the stacked sheets collapse due to the momentum of the shift operation, and the stackability is deteriorated.

  In the fourth prior art, separate drive sources (paper discharge motor, return motor) are required for the return member and the discharge means, which increases costs (because the motor and the drive driver are individually provided). There was a problem.

  The present invention solves the above-described problems of the prior art, and without increasing the cost as much as possible when there is a narrow space between sheets conveyed for discharge or when there is an image (toner) on the entire sheet, A paper stacking device that reduces the occurrence of image smudges and prevents the stacked paper from collapsing and deteriorating stackability even when the paper output tray is shifted in a paper stacking device having a tray shift mechanism. The purpose is to provide.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a sheet stacking apparatus comprising: a discharge unit that discharges a sheet to a discharge tray that stores and stores sheets; and a sheet stacking position. The sheet returning means for matching, the sheet position detecting means for detecting the position of the discharged sheet, the driving means for driving the discharging means and the sheet returning means by the same drive source, and the drive / non-drive of only the sheet returning means And a means for stopping driving of the sheet returning means after alignment of the sheet stacking positions and restarting driving of the sheet returning means when the next sheet is conveyed.

  With this configuration, the paper stacking device stops the drive of the paper returning means after alignment of the paper, and even if there is an image on the entire paper, image smear caused by unnecessary rubbing between the discharged paper and the paper returning means is eliminated. Even when the gap between the papers is narrow, the discharging means always rotates, so that it is possible to reduce the image smudge while ensuring stable paper conveyance. Since the returning means is in contact with and rotating with the loaded paper, it is possible to prevent the stacked paper from being deteriorated.

  According to a second aspect of the present invention, in the paper stacking apparatus according to the first aspect, the paper position detecting means is arranged in the vicinity of the discharging means.

  With this configuration, it is possible to know a more accurate sheet discharge timing to the sheet discharge tray, and it is possible to further reduce image contamination caused by unnecessary rubbing between the discharged sheet and the sheet returning unit.

  According to a third aspect of the present invention, in the paper stacking apparatus according to the first or second aspect, information relating to a gap between a series of sheets conveyed by the discharge means detected by the paper position detection means is received, and the information is stored in the information. Based on the above, it is characterized in that there is provided means for controlling whether or not the discharging means is stopped or driven.

  With this configuration, it is possible to stop the discharging unit when there is a time margin for stopping / restarting the driving of the discharging unit based on the information related to the paper interval, and an energy saving effect can be obtained.

  According to the present invention, the occurrence of image smearing is reduced when the interval between sheets conveyed for discharge is narrow, or when there is an image on the entire sheet, and the sheet stacking device having a tray shift mechanism is provided. Even when the paper discharge tray is shifted at, it is possible to prevent the deterioration of the stacking property that the stacked sheets are broken.

FIG. 1A is a perspective view illustrating a schematic configuration of an image forming apparatus and FIG. FIG. 3 is a perspective view illustrating a schematic configuration of a tray shift mechanism and a tray position detection unit provided in the paper stacking apparatus according to the first embodiment. 1 is a block diagram illustrating an overall circuit configuration of a sheet stacking apparatus according to a first embodiment. FIG. 3 is a schematic diagram illustrating a driving configuration of a paper discharge roller and a return member in the first embodiment. Schematic operation showing discharge / alignment operations (a) to (d) in the paper stacking apparatus according to the first embodiment. 7 is a flowchart showing a discharge / alignment operation in the paper stacking apparatus according to the first embodiment. The block diagram which shows the outline of the paper stacking apparatus in Embodiment 2 of this invention 9 is a flowchart showing the discharge / alignment operation of the paper stacking apparatus according to the third embodiment of the present invention. Configuration diagram showing the outline of a conventional paper stacking device Configuration diagram showing outlines (a) and (b) of a conventional paper stacking device Configuration diagram showing outlines (a) and (b) of a conventional paper stacking device Configuration diagram showing the outline of a conventional paper stacking device

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1A is an image forming apparatus according to the first exemplary embodiment of the present invention, and FIG. Here, components having the same functions corresponding to the components described in FIG. 9 showing the conventional example are given the same reference numerals, and the same applies to the following drawings.

  As shown in FIG. 1A, the image forming apparatus 200 according to the first embodiment includes a paper stacking apparatus 100. As shown in FIG. 1B, the paper stacking apparatus 100 includes a paper discharge roller 1, a paper discharge tray 2, and a return member 3, and is integrally attached to the side surface on the discharge side of the image forming apparatus 200.

  The paper P conveyed from the image forming apparatus 200 to the paper stacking apparatus 100 is discharged and stacked on the paper discharge tray 2 by the paper discharge roller 1. Further, the paper P discharged onto the paper discharge tray 2 is returned to the upstream side in the discharge direction by the return member 3 and is brought into contact with the end fence so that the rear ends of the paper P are aligned.

  FIG. 2 is a perspective view showing a schematic configuration of a tray shift mechanism and a tray position detection unit provided in the paper stacking apparatus according to the first embodiment. As shown in FIG. 2, the rotation of the tray shift motor 21 is transmitted to the worm gear 22 via the timing belt, and is transmitted to the worm wheel 23 that meshes with the worm gear 22. The worm wheel 23 has a pin 24 attached at an eccentric position, and this pin 24 is loosely fitted in a long hole 26 that is long in the vertical direction of the end fence 25. Further, the paper discharge tray 2 is suspended and attached to the end fence 25.

  Accordingly, the rotation of the tray shift motor 21 becomes the rotation of the worm wheel 23, and the end fence 25 is shifted in the front-rear direction perpendicular to the paper discharge direction by rotating the pin 24. Since the paper discharge tray 2 is attached to the end fence 25, the paper discharge tray 2 shifts in synchronization with the end fence 25. Further, in this way, the tray shift mechanism is configured such that the discharge tray 2 reciprocates once in the front-rear direction by one rotation of the worm wheel 23.

  The worm wheel 23 is integrally provided with a rotation detection plate 27 whose rotation center is coaxial, and the rotation detection plate 27 is provided with a plurality of slits 28 corresponding to the tray stop position. Further, a slit position sensor 29 for detecting the position of the slit 28 is provided.

  FIG. 3 is a block diagram showing an overall circuit configuration of the paper stacking apparatus according to the first embodiment. As shown in FIG. 3, the sheet stacking apparatus 100 includes a CPU (Central Processing Unit) 101, an I / O (Input / Output) interface 102, and the like. From the CPU of the image forming apparatus 200, various switches, various sensors, and the like. Is input to the CPU 101 via the I / O interface 102. Here, signals input from the image forming apparatus 200 to the sheet stacking apparatus 100 include at least a sheet passing start signal, a sheet passing end signal, a next sheet P discharging signal (sheet discharging on), and the like. The CPU 101 controls driving of a paper discharge motor 5 (hereinafter simply referred to as a drive source) that drives a paper discharge roller and a clutch 15 based on the input signal. An example of a drive driver for the clutch 15 is a transistor.

  FIG. 4 is a schematic diagram illustrating a driving configuration of the paper discharge roller and the return member of the paper stacking apparatus according to the first exemplary embodiment. As shown in FIG. 4, the paper discharge roller 1 has a paper discharge roller rotation shaft 12, two paper discharge roller rollers 11 fixed to the paper discharge roller rotation shaft 12, and two gears 17. The first gear 17 is connected by a belt 18 and a gear 17 fixed to the rotation shaft of the paper discharge motor 5 so that the driving force of the paper discharge motor 5 can be transmitted to the paper discharge roller 1. The remaining gear 17 is connected by a belt 18 so that the driving force of the discharge roller 1 can be transmitted to the intermediate roller 19.

  The intermediate roller 19 includes a clutch rotation shaft 16, two gears 17 fixed to the clutch rotation shaft 16, a clutch 15, and a gear 17 connected to the clutch 15. The two gears 17 at the center are connected by a belt 18 so that the driving force can be transmitted to the return member roller 13.

  The return member 3 includes a return member rotation shaft 14, a return member roller 13 fixed to the return member rotation shaft 14, and a gear 17.

  The clutch 15 has a function of transmitting a driving force to the intermediate roller 19 and the return member 3. When the paper discharge motor 5 rotates and the clutch 15 is off, only the paper discharge roller 1 rotates. Further, when the paper discharge motor 5 rotates and the clutch 15 is on, the paper discharge roller 1, the intermediate roller 19, and the return member 3 rotate.

  The discharge / alignment operation in the sheet stacking apparatus according to the first embodiment configured as described above will be described with reference to the operation schematic diagrams of FIGS. 5A to 5D and the flowchart of FIG.

  As shown in FIG. 5D, the return member 3 and the paper P are always in contact with the paper P stacked on the paper discharge tray 2 regardless of whether the clutch 15 and the paper discharge motor 5 are on or off. It is characterized by. In the first embodiment, the contact method is configured such that the return member 3 can be contacted by its own weight, but the method is not limited thereto.

  Control by the flowchart of FIG. 6 is executed by the CPU 101 of FIG. When the paper passing process is started, first, the paper discharge motor 5 is turned on (see FIG. 5A), and the paper discharge roller 1 is rotated in the direction of feeding the paper P to the paper discharge tray 2 (step S1). Subsequently, it is determined whether or not the paper passing process is completed (step S2). If the paper passing process is not completed (No in S2), the paper P is accepted (step S3), and the paper P is detected by the paper discharge sensor 30. It is determined whether or not the rear end has been detected (step S4). If the trailing edge of the paper is detected (Yes in S4), the clutch 15 is turned on (step S5: see FIG. 5B), and time measurement is started or the number of pulses is confirmed (step S6). ), It is determined whether or not a predetermined time has passed (step S7: see FIG. 5C).

  If it is determined that the predetermined time has elapsed (Yes in S7), the tray shift request is confirmed in FIG. 5D when the clutch 15 is on (step S8), and if there is a request (in S8). Yes) A tray shift operation is executed (step S9), the clutch 15 is turned off (step S10: see FIG. 5D), and it is determined again whether or not the sheet passing process is completed (step S2). If the paper passing process is completed (Yes in S2), the paper discharge motor 5 is turned off (step S11), and the paper passing process is ended.

  Here, if the return member 3 is stopped during the tray shift operation, the uppermost sheet P is displaced by the frictional force of the return member 3, so that during the tray shift operation, the return member 3 is used to reduce the frictional force. Is rotating, that is, the clutch 15 is on.

  With this configuration, the sheet stacking apparatus stops driving the return member 3 after the sheets are aligned, and reduces image contamination caused by unnecessary rubbing between the discharged paper and the return member 3 even if there is an image on the entire sheet. In addition, even when the gap between the sheets is narrow, the discharge means is always rotating, so that it is possible to reduce image contamination while ensuring stable sheet conveyance.

  Further, during the tray shift, the return member 3 is in contact with and rotating with the stacked sheets, so that it is possible to prevent the stackability of the stacked sheets from deteriorating.

  FIG. 7 is a configuration diagram showing an outline of a sheet stacking apparatus according to the second embodiment of the present invention. As shown in FIG. 7, in the second embodiment, the position of the paper discharge sensor 30 is different from that in the first embodiment, and the paper discharge sensor 30 is disposed in the vicinity of the paper discharge roller 1. The description of the discharging operation is omitted because it is the same as that of the first embodiment using FIGS.

  With this configuration, it is possible to know a more accurate discharge timing of the paper P to the paper discharge tray 2 and to further reduce image contamination caused by unnecessary rubbing between the paper P to be discharged and the return member 3. Can do.

  FIG. 8 is a flowchart showing the discharge / alignment operation of the sheet stacking apparatus according to the third embodiment of the present invention. The control in the flowchart of FIG. 8 of the third embodiment is executed by the CPU 101 shown in FIG.

  When the paper passing process is started, the paper discharge motor 5 is first turned on (step S21). Subsequently, it is determined whether or not the sheet passing process has been completed (step S22). If the sheet passing process has not been completed (No in S22), the sheet is accepted (step S23), and a preceding apparatus such as the image forming apparatus 200 is received. It is determined whether or not there is information relating to the sheet interval such as the sheet interval and the sheet interval (step S24). If there is paper gap information (Yes in S24), it is determined whether the paper gap is 1000 mm or more (step S25). Here, the paper gap is 1000 mm as an example, but it is an arbitrary value.

  If the paper gap is 1000 mm or more (Yes in S26), it is determined that there is enough time to stop / restart the paper discharge motor 5, the paper discharge motor 5 is turned off (step S26), and time measurement is started. Alternatively, the number of pulses is confirmed (step S27). It is determined whether or not a predetermined time has elapsed (step S28). If it is determined that the predetermined time has elapsed (Yes in S28), the paper discharge motor 5 is turned on (step S29), and the trailing edge of the paper is detected. It is determined whether or not (step S30). In step S25, if the paper gap is less than 1000 mm (No in S25), there is no time margin required to stop / restart the paper discharge motor 5, so the paper discharge motor 5 remains on. The process proceeds to the next process S30.

  If the trailing edge of the sheet is detected (Yes in S30), the clutch 15 is turned on (Step S31), time measurement is started or the number of pulses is checked (Step S32), and whether or not a predetermined time has elapsed. Is determined (step S33).

  If it is determined that the predetermined time has elapsed (Yes in S33), the tray shift request is confirmed (Step S34). If there is a request (Yes in S34), the tray shift operation is executed (Step S35). Then, the clutch is turned off (step S36), and it is determined again whether or not the paper passing process is completed (step S22). If the paper passing process has been completed (Yes in S22), the paper discharge motor 5 is turned off (step S37), and the paper passing process is completed.

  With this configuration, when there is a time margin for stopping / restarting the driving of the discharge unit from the paper gap information, it is possible to stop the discharge unit (paper discharge motor 5). Can be obtained.

  The paper stacking apparatus according to the present invention reduces the occurrence of image smearing when there is a narrow space between papers transported for discharge or when there is an image on the entire paper, and has a tray shift mechanism. Even when the paper discharge tray is shifted in the paper stacking device, it is possible to prevent deterioration of stackability, which causes the stacked paper to collapse, and is useful as a device for stacking discharged paper.

DESCRIPTION OF SYMBOLS 1 Paper discharge roller 2 Paper discharge tray 3 Return member 4 Drive belt 5 Paper discharge motor 6 Solenoid 7 Folder 8 Return motor 11 Paper discharge roller roller 12 Paper discharge roller rotating shaft 13 Return member roller 14 Return member rotating shaft 15 Clutch 16 Clutch rotation shaft 17 gear 18 belt 19 intermediate roller 21 tray shift motor 22 worm gear 23 worm wheel 24 pin 25 end fence 26 long hole 27 rotation detection plate 28 slit 29 slit position sensor 30 paper discharge sensor

JP 2007-76903 A JP 2005-255332 A

Claims (3)

  A discharge means for discharging the paper to a paper discharge tray for storing and storing paper; a paper return means for aligning the paper stack position; and a paper position detection means for detecting the position of the discharged paper. The drive means for driving the discharge means and the paper return means by the same drive source and the drive / non-drive of only the paper return means are switched, and the paper return means is driven after alignment of the paper stacking positions. A paper stacking apparatus, comprising: means for stopping and restarting driving of the paper returning means when the next paper is conveyed.   The sheet stacking apparatus according to claim 1, wherein the sheet position detection unit is disposed in the vicinity of the discharge unit.   Means for receiving information related to a gap between a series of sheets conveyed by the discharge means detected by the paper position detection means, and controlling whether to stop or drive the discharge means based on the information; The sheet stacking apparatus according to claim 1, further comprising a sheet stacking apparatus.

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