JP2015044634A - Sheet processor and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sheet from being erroneously detected by stacking sheets on a sheet discharge tray in a state where the sheet is lifted and reducing the number of sheets that can be actually stacked. And an image forming apparatus including the sheet processing apparatus.
A sheet processing apparatus according to an embodiment includes a paper discharge tray, an elevating mechanism, and a pressing mechanism. The sheet discharge tray stacks sheets on which images are formed. The elevating mechanism elevates and lowers the discharge tray. The pressing member presses the upper surface of the sheet on the paper discharge tray raised by the lifting mechanism at the first position.
[Selection] Figure 5

Description

  Embodiments described herein relate generally to a sheet processing apparatus that performs predetermined processing on a sheet on which an image is formed by an image forming apparatus, and an image forming apparatus that includes the sheet processing apparatus.

  In a conventional sheet processing apparatus, for example, a sheet discharged to a sheet discharge tray may be curled by image formation and fixing processing. When the sheets are curled and stacked on the paper discharge tray, the sheets are lifted and stacked, so that the sensor detects that the number of sheets is larger than the number of sheets originally stacked. For this reason, there is a problem that the number of sheets that can be loaded becomes smaller than the original number.

JP 2000-219397 A

  The problem to be solved by the embodiment of the present invention is that the number of sheets on the sheet discharge tray is erroneously detected by stacking the sheets on the sheet discharge tray in a state where the sheets are lifted, and the number of sheets that can be actually stacked is It is an object of the present invention to provide a sheet processing apparatus that suppresses the decrease and an image forming apparatus including the sheet processing apparatus.

  The sheet processing apparatus according to the embodiment includes a paper discharge tray, an elevating mechanism, and a pressing mechanism. The sheet discharge tray stacks sheets on which images are formed. The elevating mechanism elevates and lowers the discharge tray. The pressing member presses the upper surface of the sheet on the paper discharge tray raised by the lifting mechanism at the first position.

1 is a cross-sectional view of an image forming apparatus according to an embodiment. Sectional drawing of the sheet processing apparatus in this embodiment. FIG. 3 is a perspective view of a processing tray in the sheet processing apparatus illustrated in FIG. 2. FIG. 3 is a control block diagram of a hardware configuration of the image forming apparatus illustrated in FIG. 1 and the sheet processing apparatus illustrated in FIG. 2. Sectional drawing of the movable tray periphery in this embodiment. 7 is a control flowchart in sheet discharge processing.

  Embodiments for carrying out the invention will be described below with reference to FIGS. 1 to 6. The sheet processing apparatus of the present embodiment is used by being connected to the subsequent stage of the image forming apparatus.

  The configuration and operation of the image forming apparatus 100 according to the present embodiment will be described below. FIG. 1 is a cross-sectional view of an image forming apparatus 100 according to the embodiment. The image forming apparatus 100 according to the present embodiment includes an image reading unit 110 at the top of the housing. The image forming apparatus 100 includes a fixing unit 140 along a sheet conveyance path that leads from a paper feeding unit 120 provided below the housing to a paper discharge unit 150 provided below the image reading unit 110. Further, an image forming unit 130 is disposed between the paper feeding unit 120 and the paper discharge unit 150. The image transfer position of the image forming unit 130 is upstream of the fixing unit 140 and is along the sheet conveyance path.

  The image reading unit 110 has a known configuration, and includes a carriage 112 having an exposure lamp and a reflection mirror, a CCD (Charge Coupled Device) sensor 114, and the like. The carriage 112 reflects the image on the document placed on the document placement table and causes the reflected light to enter the CCD sensor 114. The CCD sensor 114 outputs incident light to the image forming unit 130 as an image signal. As illustrated in FIG. 1, the image reading unit 110 may further include an ADF (Auto Document Feeder) 116. The ADF 116 conveys the originals one by one to the reading position on the original placement table, and discharges the original after the reading process.

  The sheet feeding unit 120 includes a sheet feeding cassette 122 that stores a plurality of sheets and a manual feeding unit 124. As shown in FIG. 1, a plurality of sheet feeding cassettes 122 may be provided so as to accommodate sheets of different sizes such as A3 and A4. For example, the manual feed portion 124 is rotatably provided in the main body of the image forming apparatus 100, and is set by being rotated from the main body when used. The sheet feeding unit 120 takes out the sheets placed on the sheet feeding cassette 122 or the manual feeding unit 124 one by one and conveys the sheets to the image forming unit 130 via the conveyance path.

  The image forming unit 130 has a known configuration, and includes, for example, an image forming unit including a photosensitive drum, an intermediate transfer belt, and a developing unit using toner as a developer. The image forming unit 130 receives an image of a document read by the image reading unit 110 on a photosensitive drum charged to a predetermined potential, or a communication interface (communication I / F) unit 190 (see FIG. 4) described later. An electrostatic latent image is formed based on the printed data. The image forming unit 130 further develops the photosensitive drum on which the electrostatic latent image is formed with a developer using a developing unit, thereby forming a visible image (toner image) of the electrostatic latent image. This visible image is transferred to the intermediate transfer belt, and further transferred onto a sheet supplied from the paper feeding unit 120 at a predetermined transfer position. In this embodiment, the image forming unit 130 includes a plurality of developing units corresponding to a plurality of colors (yellow (Y), magenta (M), cyan (C), and black (K)) as shown in FIG. It is possible to adopt either a configuration in which a color image is formed or a configuration in which only a monochrome image is formed by a single developing unit without an intermediate transfer belt.

  The fixing unit 140 has a known configuration, and includes, for example, a heating roller and a pressure roller. The fixing unit 140 fixes the image on the sheet on which the above-described visible image is transferred and passes through a nip formed by these rollers by heat from the heating roller and pressure from the pressure roller.

  The paper discharge unit 150 aligns and places the sheets conveyed from the fixing unit 140. The paper discharge unit 150 of the present embodiment uses a connection unit (not shown) with a known sheet processing apparatus to convey the sheet on which the image is formed to the sheet processing apparatus 200 shown in FIG.

  FIG. 2 is a cross-sectional view of the sheet processing apparatus 200 in the embodiment. The sheet processing apparatus 200 performs so-called post-processing such as stapling and sorting on sheets such as paper. The sheet processing apparatus 200 includes an inlet roller pair 210, a branching member 215, a first paper discharge roller pair 220, and a fixed tray 225 that are positioned along the sheet conveyance direction. This sheet conveyance path is used for conveying a sheet that does not require the post-processing. The sheet processing apparatus 200 further includes an exit roller pair 230, a processing tray 250, a stapler 270, and a movable tray (sheet discharge tray) that are positioned downstream (hereinafter simply referred to as downstream) in the sheet conveyance direction branched by the branch member 215. 280.

  The inlet roller pair 210 receives a sheet on which an image has been formed by the image forming apparatus 100 located in the preceding stage, and conveys the sheet to the branching member 215. The branching member 215 conveys the sheet to the first discharge roller pair 220 or the exit roller pair 230 in accordance with an instruction from the control unit 300 (see FIG. 4) based on the input sheet processing. When post-processing is not requested, for example, the branch member 215 is not driven, and the sheet is conveyed to the first paper discharge roller pair 220. The first paper discharge roller pair 220 discharges the sheet to the fixed tray 225. On the other hand, when post-processing is required, for example, the branch member 215 is driven, and the sheet is conveyed to the exit roller pair 230. The exit roller pair 230 conveys the sheet to the processing tray 250.

  The processing tray 250 receives the sheet conveyed from the exit roller pair 230. The sheet received by the processing tray 250 is subjected to sort processing and stapling processing. The stapling process is performed at a predetermined position by a stapler 270 provided upstream of the processing tray 250 in the sheet conveyance direction (hereinafter simply referred to as upstream). The processed sheet is discharged to the movable tray 280.

  The movable tray 280 aligns and stacks the sheets discharged from the processing tray 250. The movable tray 280 according to the present embodiment moves up and down according to the sheet discharge operation from the processing tray 250 and the sheet stacking amount.

  The fixed tray 225, the processing tray 250, and the movable tray 280 are provided so as to be inclined upward toward the downstream side in order to align sheets or sheet bundles.

  FIG. 3 is a perspective view of the processing tray 250 in the sheet processing apparatus 200 shown in FIG. The processing tray 250 includes a pair of horizontal alignment plates 252, a pair of vertical alignment rollers 254, and a pair of rear end stoppers 256 in order to align the sheets conveyed from the exit roller pair 230. The lateral alignment plates 252 are provided at both ends in the width direction orthogonal to the sheet conveyance direction of the sheet support surface that receives the sheets of the processing tray 250. The lateral alignment plate 252 aligns the width direction of the sheet by reciprocating in the opposite directions by the same distance in the width direction by a driving mechanism (not shown). The vertical alignment roller 254 is provided with a gap at the center of the rear end of the processing tray 250 in the sheet conveyance direction. The rear end stopper 256 is provided so as to protrude in the upstream direction from the rear end portion of the processing tray 250. The vertical alignment roller 254 transports the sheet placed on the sheet support surface to the upstream side of the processing tray 250 in cooperation with a later-described second paper discharge roller 258 by the driving mechanism 266, and the sheet to the trailing edge stopper 256. The vertical alignment of the sheet is performed by contacting the sheet.

  Further, the processing tray 250 includes a second paper discharge roller 258, an ejector 260, a bundle hook belt 262, and a bundle hook 264 for discharging sheets to the movable tray 280. The second paper discharge roller 258 is provided at the front end of the sheet support surface in the sheet conveyance direction. The second paper discharge roller 258 of this embodiment has, for example, four drive rollers. The ejector 260 is provided so as to protrude in the upstream direction from the central portion on the rear end side of the processing tray 250. Two ejectors 260 of this embodiment are provided between the central vertical alignment rollers 254, and reciprocate in pairs in the sheet conveying direction by a driving mechanism. The ejector 260 delivers the stapled sheet to the bundle hook 264. The bundle claw 264 is attached to the bundle claw belt 262. The bundle hook belt 262 is wound around a driving roller and a driven roller provided at the center of the processing tray 250. The bundle claw 264 moves along the sheet conveyance direction as the bundle claw belt 262 moves due to the drive roller being rotated by the drive mechanism 268. The bundle hook 264 discharges the sheet delivered from the ejector 260 together with the second discharge roller 258 from the processing tray 250 to the movable tray 280.

  FIG. 4 is a control block diagram of the hardware configuration of the image forming apparatus 100 shown in FIG. 1 and the sheet processing apparatus 200 shown in FIG. The image forming apparatus 100 according to the present exemplary embodiment includes a main control unit 160, an image reading unit 110, a paper feeding unit 120, an image forming unit 130, a fixing unit 140, a conveying unit 175, an operation unit 180, and a communication I / F unit 190. . Each unit is connected to each other via a bus line 195.

  The main control unit 160 includes a processor 162 composed of a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), a memory 164, and a storage device. The memory 164 is, for example, a semiconductor memory, and includes a ROM (Read Only Memory) 166 that stores various control programs, and a RAM (Random Access Memory) 168 that provides a temporary work area to the processor 162. The storage device 170 may be, for example, a hard disk drive, another magnetic storage device, an optical storage device, a semiconductor storage device such as a flash memory, or any combination thereof. The main control unit 160 comprehensively controls each unit of the image forming apparatus 100 based on various programs stored in the ROM 166 or the storage device 170.

  The conveyance unit 175 conveys the sheet conveyed from the paper supply unit 120 to the paper discharge unit 150 via the transfer position of the visible image and the fixing unit 140 described above along the conveyance path. The conveyance unit 175 includes a plurality of conveyance roller pairs including a driving roller and a driven roller, for example, in order to convey the sheet.

  The operation unit 180 includes a display unit including various operation keys and a touch panel type input unit. The operation keys include, for example, a numeric keypad, a reset key, a stop key, and a start key. The display unit displays instruction items related to printing conditions such as sheet size, number of copies, print density setting, and finishing (binding, folding, bookbinding), for example. The operation unit 180 receives input from the user from an operation key or a display unit.

  The communication I / F unit 190 is an interface that connects an external terminal such as the sheet processing apparatus 200, a PC, or a print server to the main control unit 160 via a network. The communication I / F unit 190 includes an appropriate wireless or wired interface such as IEEE802.15, IEEE802.11, IEEE802.3, IEEE1284, such as Bluetooth (registered trademark), infrared connection, or optical connection. The communication I / F unit 190 may further include a USB connection unit or a parallel interface to which a USB standard connection terminal is connected. The main control unit 160 communicates with the control unit 300 of the sheet processing apparatus 200 (to be described later), a user terminal, a USB device, and other external devices via the communication I / F unit 190. The communication I / F unit 190 receives print data from a user terminal, for example. Since the image reading unit 110, the paper feeding unit 120, the image forming unit 130, and the fixing unit 140 have already been described, description thereof will be omitted.

  Next, the hardware configuration of the sheet processing apparatus 200 will be described. The sheet processing apparatus 200 according to the present embodiment includes a control unit 300, a conveyance unit 320, a stapler 270, a processing tray 250, a movable tray 280, and a pressing member 290. Each part is connected to each other via a bus line 330.

  The control unit 300 includes a processor 302, a memory 304, and a storage device 310, similarly to the main control unit 160 of the image forming apparatus 100. The control unit 300 communicates with the main control unit 160 of the image forming apparatus 100. The control unit 300 comprehensively controls each unit of the sheet processing apparatus 200 based on information received from the main control unit 160 or various programs stored in the ROM 306 or the storage device 310. Since the conveying unit 320, the stapler 270, and the processing tray 250 have already been described, description thereof will be omitted. The movable tray 280 and the pressing member 290 will be described later.

  The movable tray 280 will be described below. FIG. 5 is a cross-sectional view around the movable tray 280 in the present embodiment. The movable tray 280 is provided downstream of the processing tray 250 and stacks sheets discharged from the processing tray 250. The movable tray 280 is connected to an elevating mechanism (not shown) that moves the movable tray 280 up and down by a known technique. In addition, the movable tray 280 has a full detection sensor 285 (second sensor) (see FIG. 4) that detects that the amount of sheets stacked on the movable tray 280 is full.

  The lifting mechanism is, for example, a motor. The movable tray 280 moves up and down as the motor connected to the belt rotates. The movable tray 280 is moved to the first height (initial height) when the sheet discharge processing of the sheet processing apparatus 200 starts. The first height is a variable position that maintains the upper surface of the movable tray 280 or the uppermost surface of the sheets stacked on the movable tray 280 (hereinafter collectively referred to as the uppermost surface of the movable tray 280) at a certain height. It is. That is, the first height decreases from the initial height when no sheets are placed on the movable tray 280 as the amount of sheets stacked on the movable tray 280 increases (displacement height). It is. The fixed height is a height at which the sheets stacked on the movable tray 280 do not hinder the movement of the pressing member 290 described later.

  When the sheet is discharged to the movable tray 280, the movable tray 280 is raised. When a sheet upper surface detection sensor 295 (first sensor) (see FIG. 4), which will be described later, detects the uppermost surface of the movable tray 280, the movable tray 280 stops rising and descends to a first height that is a displacement position. The first height (displacement height) at this time is lower than before the sheets are discharged to the movable tray 280 by the amount of sheets stacked on the movable tray 280. The above operation is repeated until all sheets according to the given job are discharged, and the first height (displacement height) of the movable tray also changes stepwise. When the full detection sensor 285 detects that the first height falls below a predetermined second height (fixed position) on the way, the control unit 300 determines that the sheet on the movable tray 280 is full.

  Next, the pressing member 290 will be described. The pressing member 290 is provided below the processing tray 250. The pressing member 290 is preferably a plate having a width longer than the width direction of the discharged sheet. The pressing member 290 presses the sheets stacked on the movable tray 280 from the upper surface and detects the uppermost surface of the movable tray 280. The pressing member 290 includes a driving mechanism (not shown) that moves the pressing member 290 from a first position, which will be described later, to a second position or from the second position to the first position, and an uppermost surface of the movable tray 280. A sheet upper surface detection sensor 295 is detected. When the pressing member 290 presses the rear end portion of the sheet, it is possible to suppress the erroneous detection of the uppermost surface due to the floating of the sheet and the erroneous detection of the full sheet on the movable tray 280 accompanying the erroneous detection. Further, the pressing member 290 formed in a plate shape can be pressed regardless of the size of the sheet.

  The drive mechanism that operates the pressing member 290 is, for example, a motor. The pressing member 290 has a rack, for example, and moves according to the rotation of the motor by meshing with a pinion connected to the motor. The drive mechanism is not limited to a motor, and a solenoid or the like may be used.

  The front end portion of the pressing member 290 has elasticity in the vertical direction. The sheet upper surface detection sensor 295 detects the uppermost surface of the movable tray 280 by moving the movable tray 280 upward and the sheet displacing the front end portion of the pressing member 290 by a predetermined amount. More specifically, when the pressing member 290 applies pressure from above to the moving tray 280 that rises, the tip of the pressing member 290 is displaced upward by a predetermined amount due to the action / reaction force. The sheet upper surface detection sensor 295 detects the position as the uppermost surface of the movable tray 280.

  FIG. 5A is a cross-sectional view around the movable tray 280 showing the first position. The first position is a position (working position) where the pressing member 290 moves downstream, the leading end thereof is positioned above the movable tray 280, and the upstream end of the sheet placed on the movable tray 280 is pressed. ). The pressing member 290 corrects the sheet stacked while being lifted on the movable tray by pressing the end of the sheet, so that the full detection sensor 285 erroneously detects the sheet stacking amount on the movable tray 280. Can be suppressed.

  FIG. 5B is a cross-sectional view around the movable tray 280 showing the second position. The second position is a position (initial position) where the pressing member 290 is positioned below the processing tray 250 in the frame of the sheet processing apparatus 200 and does not contact the sheet discharged from the processing tray 250 to the movable tray 280. is there.

  FIG. 6 is a control flowchart in sheet discharge processing. When the sheet is discharged from the processing tray 250 to the movable tray 280, the control unit 300 arranges the movable tray 280 at the first height (initial height) (ACT101). The controller 300 adjusts the height of the movable tray 280 via the belt by rotating the motor, which is a lifting mechanism, forward or backward. At this time, the pressing member 290 is in the second position (initial position) shown in FIG. Next, the control unit 300 discharges the sheet on the processing tray 250 to the movable tray 280 (ACT 102). The control unit 300 drives each member to discharge a sheet that has undergone alignment and predetermined processing in the processing tray 250 to the movable tray 280. The number of discharged sheets is one sheet, or the maximum number of sheets that can be processed by the processing tray 250 at one time when the stapling process is performed. When the sheet is discharged to the movable tray 280, the control unit 300 moves the pressing member 290 to the first position shown in FIG. 5A via the driving mechanism (ACT 103). Next, the control unit 300 raises the movable tray 280 from the first height (initial height) (ACT 104). The pressing member 290 is in contact with the uppermost surface of the sheet stacked on the movable tray 280 rising and presses the upstream end of the stacked sheet to correct the sheet lift. . Further, when the movable tray 280 is raised, the pressing member 290 corrects the lifting of all the sheets stacked on the movable tray 280, and the upward force from the sheet bundle accompanying the rise of the movable tray 280 The tip portion having elasticity of the pressing member 290 is displaced upward. When the sheet upper surface detection sensor 295 detects that the amount of displacement exceeds a certain amount (ACT 105, Yes), the control unit 300 stops the rising of the movable tray 280, and is variable according to the increment of the sheet on the movable tray 280. It is lowered to a first height (displacement height) lower than the first height (initial height) (ACT 106). Since the movement of the pressing member 290 is not hindered by the sheet on the movable tray because the movable tray 280 is lowered to the first height (displacement height), the control unit 300 moves the pressing member 290 to the second position. Move (ACT 107). By the movement to the second position, the sheet discharge to the movable tray 280 is not hindered by the pressing member 290. When the full detection sensor 285 detects that the height (displacement height) of the movable tray 280 at this time is lower than the second height (ACT 108, No), the control unit 300 is loaded on the movable tray 280. It is determined that the number of sheets is a predetermined amount (ACT 109). When the full detection sensor 285 detects a predetermined amount of sheets, the control unit 300 ends the processing of the sheet processing apparatus 200. On the other hand, when the number of sheets on the movable tray 280 is not the predetermined amount (ACT 108, Yes), the control unit 300 determines whether or not the discharge of all the sheets has been completed (ACT 110). When the discharge of all sheets is completed (ACT 110, Yes), the control unit 300 ends the discharge process. When the sheet discharge process has not been completed (ACT 110, No), the control unit 300 performs the next sheet discharge process (ACT 102).

  According to the above-described embodiment, since the pressing member corrects the floating of the sheets stacked on the movable tray, the sensor detects the full state of the sheets in a state where the number of sheets is smaller than the number of sheets that can be originally stacked. It is possible to suppress this.

  The present invention is not limited to the above embodiment, and various modifications are possible. For example, the sheet upper surface detection sensor and the fullness detection sensor are not limited to those according to the above-described detection method, and various known sensors that can detect the sheet upper surface detection and fullness may be used.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus 130 ... Image forming part 200 ... Sheet processing apparatus 280 ... Movable tray (paper discharge tray)
285: Full detection sensor (second sensor)
290 ... Pressing member 295 ... Seat upper surface detection sensor (first sensor)
300 ... control unit

Claims (6)

A paper discharge tray for stacking sheets on which images are formed;
An elevating mechanism for elevating and lowering the output tray;
A pressing member that presses the upper surface of the sheet on the sheet discharge tray raised by the lifting mechanism at the first position;
A sheet processing apparatus comprising: A first sensor for detecting an upper surface of the paper discharge tray;
A control unit for controlling the lifting mechanism according to the detection output of the sensor to lower the discharge tray;
The sheet processing apparatus according to claim 1, further comprising: The pressing member is formed of an elastic body at a tip portion that contacts the upper surface of the sheet on the paper discharge tray,
The sheet processing apparatus according to claim 2, wherein the first sensor detects an uppermost surface of the paper discharge tray by detecting a displacement of the pressing member due to a rise of the paper discharge tray. A drive mechanism that positions the pressing member at the first position and a second position that does not interfere with sheet discharge to the sheet discharge tray;
The driving mechanism moves the pressing member to the first position after a sheet is discharged to the discharge tray, and the pressing member after the first sensor detects the uppermost surface of the discharge tray. The sheet processing apparatus according to claim 2, wherein the sheet processing apparatus is moved to the second position. A second sensor for detecting that the displacement height of the discharge tray is lower than a predetermined height;
The sheet processing apparatus according to any one of claims 2 to 4, wherein the control unit determines that the amount of sheets on the sheet discharge tray reaches a predetermined amount based on a detection output of the second sensor. An image forming unit that forms an image on a sheet;
After the image is formed by the image forming unit, a predetermined process is performed, and a discharge tray for stacking the discharged sheets, a lift mechanism for moving the discharge tray up and down, and a lift mechanism A sheet processing apparatus having a pressing member that presses the upper surface of the sheet on the sheet discharge tray to be raised at the first position;
An image forming apparatus comprising:

Images