JP2007062866A - Sheet processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet processing device capable of preventing any collapse of a sheet bundle by enhancing the stacking property of the sheet bundle on a sheet stacking tray even selecting the offset mode when stacking a large amount of sheets on the sheet stacking tray by a post-processing device having a sorting device for sorting the bundle by alternately shifting the sheets to the proximal/distal side by the bundle. <P>SOLUTION: When the offset mode is set, and when the number of sheets stacked in a stack tray is large, the sheet processing device controls the offset quantity to prevent degradation of the stacking property. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet post-processing apparatus that performs predetermined post-processing on sheets output from image forming apparatuses such as copiers, printers, and facsimiles, and in particular, sorts sheets by alternately shifting the sheets forward and backward for each bundle. The present invention relates to a sheet post-processing apparatus that stacks bundles that have been sorted and sorted.

  2. Description of the Related Art Conventionally, a post-processing device that performs post-processing such as binding processing and sorting processing on an image-formed sheet discharged from an image forming device such as a copying machine, a fax machine, a multifunction device, or a laser beam printer is used as the image forming device. There is an image forming system that is mounted and automatically performs post-processing on a transfer material.

  Some post-processing apparatuses used in such an image forming system include a sorting mechanism that sorts bundles by alternately shifting sheets forward and backward for each bundle. By this sorting mechanism, the discharged sheet bundle is stacked on the sheet stacking means in a state where the sheet bundle is alternately offset in the horizontal direction. With such a sorting state, the visibility of each stacked sheet bundle is improved.

  In such conventional sorting, the amount of offset of the sheet is normally set constant. By offsetting the sheet bundle, the area of the stacking part of the sheet bundle on the stacking means is reduced, and the end of the sheet hangs downwards alternately, so the sheet stacks downward. When the number of stacked sheets on the means increases, the stacking state becomes unstable, and problems such as collapse of sheets on the sheet stacking means occur.

Conventionally, when the paper sizes in the width direction are mixed and stacked on the sheet stacking unit, there is a configuration in which the offset amount is controlled according to the sheet width size (see, for example, Patent Documents 1 and 2). Thereby, the area of the stacking portion of the sheet bundles when the sheet width size is mixed is increased, and the stackability on the sheet stacking means is improved.
Japanese Patent Laid-Open No. 10-194556 JP 2000-44109 A

  However, even if the configuration is as described above, the offset amount is constant when jobs having the same size of stacked sheet bundles continue. Therefore, when the end of the sheet hangs downward and the number of sheets stacked on the sheet stacking unit increases, the stacking state becomes unstable due to the influence of the sag of the sheet end. This makes it difficult to increase the number of sheets that can be stacked on the sheet stacking tray when the sorting mode is selected based on the offset of the stacking amount.

  In order to achieve the above object, a sheet processing apparatus according to the present invention includes a sheet stacking unit that stacks discharged sheets, an offset unit that shifts a sheet in a direction orthogonal to a conveyance direction, and the offset for each predetermined number of sheets. An offset mode setting means for setting an offset mode for stacking the sheets on the sheet stacking means in a state where the sheets are alternately shifted by the means, an offset amount control means for controlling the offset amount in the offset means, and before starting the job, And a scheduled number detection unit for detecting the number of sheets to be stacked on the sheet stacking unit. When the offset mode is set by the offset mode setting unit, the detection is performed by the planned number of sheets detection unit before starting the job. If the number of sheets stacked on the sheet stacking means exceeds a predetermined number, the offset amount control And it controls to change the offset amount of the sheet by means, and performs loading of the sheet to the sheet stacking means.

  In addition, the sheet processing apparatus according to the present invention includes a sheet stacking unit that stacks discharged sheets, an offset unit that shifts the sheet in a direction orthogonal to the conveyance direction, and a sheet that is alternated by the offset unit every predetermined number of sheets. An offset mode setting means for setting an offset mode for stacking on the sheet stacking means in a shifted state, an offset amount control means for controlling an offset amount in the offset means, and detecting the number of discharged sheets to the sheet stacking means And when the offset mode is set by the offset mode setting means, the offset amount control means each time the detection means detects a predetermined number of sheets discharged to the sheet stacking means. The sheet to the sheet stacking means is controlled by changing the offset amount by And performing the loading.

  When stacking a large number of sheets on the sheet stacking tray, even when the offset mode is selected, the sheet bundle can be prevented from collapsing by improving the stackability of the sheet stack on the sheet stacking tray. In addition, the maximum number of sheets stacked on the sheet stacking tray can be increased.

  Hereinafter, an embodiment of a post-processing apparatus including a stacking unit for sheets output from an image forming apparatus in the image forming system will be described. Here, an example using a copying machine as an image forming apparatus and a finisher as a post-processing apparatus will be described with reference to the drawings.

[First embodiment]
(overall structure)
FIG. 1 is a sectional view showing the internal structure of the entire image forming system according to the embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body including a printer 100 and an image reader 200, a document feeder 400, a finisher 500, and an operation unit 600.

  A document feeder 400 is mounted on the image reader 200. The document feeder 400 feeds the documents set upward on the document tray one by one from the first page in order to the left, stops the platen glass 202 at a predetermined position through a curved path, and in this state The original is read by scanning the scanner unit 201 from left to right. When the scanner unit 201 scans, the reading surface of the document is irradiated with the light of the lamp of the scanner unit 201, and the reflected light from the document is guided to the lens through the mirror. The light that has passed through this lens forms an image on the imaging surface of the image sensor 203. The optically read image is converted into image data by the image sensor 203 and output. Image data output from the image sensor 203 is input as a video signal to the exposure control unit 101 of the printer 100 after being subjected to predetermined processing in an image signal control unit 281 described later.

  Hereinafter, the case where image formation is performed on one side of a sheet will be described with reference to FIG. The exposure control unit 101 of the printer 100 modulates and outputs laser light based on the input video signal, and the laser light is irradiated onto the photosensitive drum 102 while being scanned by a polygon mirror or the like (not shown). An electrostatic latent image corresponding to the scanned laser beam is formed on the photosensitive drum 102.

  The electrostatic latent image on the photosensitive drum 102 is visualized as a developer image by the developer supplied from the developing device 103. Further, the sheet fed to the conveyance path from each cassette 111, 112 or the manual sheet feeding tray 113 is abutted against the registration roller 114, and after stopping, the laser beam irradiation starts. The sheet is transported between the photosensitive drum 102 and the transfer unit 104 at a timing synchronized with. The developer image formed on the photosensitive drum 102 is transferred onto a sheet fed by the transfer unit 104. Further, the leading edge of the sheet is abutted against the registration roller 114 and temporarily stops, thereby correcting the inclination of the sheet.

  The sheet on which the developer image has been transferred is conveyed to the fixing unit 105, and the fixing unit 105 fixes the developer image on the sheet by heat-pressing the sheet. The sheet that has passed through the fixing unit 105 is conveyed by the flapper 125 from the printer 100 to the finisher 500 via the discharge roller 116. At this time, the sheet is carried out in a face-up state.

  In order to discharge the sheet in a face-down state, the flapper 125 is switched when the sheet passes through the fixing unit 105, the sheet is carried into the sheet reversal conveyance path 121, and the sheet is switched back, so that the front and back of the sheet are reversed. The discharge roller 116 is obtained and discharged from the printer 100 toward the finisher 500.

  The sheet discharged from the printer 100 is sent to the finisher 500. The finisher 500 can perform stapling, sorting, and the like on the sheet bundle, and the operation display unit 600 can select and cancel the stapling mode and the sorting mode. When post-processing such as sorting and stapling is not set, and the sheet is discharged as it is, the flapper 518 is switched, and is discharged to the stack tray 510 by the conveying roller 517 via the non-sort path 516.

  Next, with reference to FIG. 4, sheet conveyance when post-processing such as sorting and stapling is set for sheets will be described. Image formation is performed in the same manner as when image formation is performed on one side of a sheet. When the sheet passes through the fixing unit 105, the flapper 125 is switched, and the sheet is carried into the sheet reverse conveyance path 121, and the sheet is switched back. The printer 100 is discharged from the printer 100 to the finisher 500 in a face-down state. In order to perform post-processing on the sheet, the sheet is conveyed to the buffer roller 520 through the discharge roller 501 of the finisher 500.

  The buffer roller 520 is a roller capable of laminating a predetermined number of sheets sent to the outer periphery of the buffer roller 520, and is wound around the outer periphery of the roller as necessary. The wound sheet is conveyed in the rotation direction of the buffer roller 520. A flapper 521 is disposed on the outer periphery of the buffer roller 520. The flapper 521 is a flapper for peeling the sheet wound around the buffer roller 520 and guiding it to the sort conveyance path 519.

  The sheet that has passed through the buffer roller 520 is discharged onto the bundle discharge belt 503 by the transfer roller 502 through a sort transfer path 519. A low-friction intermediate processing tray is provided at a position several millimeters higher in parallel with the bundled paper discharge belt 503, and the sheet is accurately discharged onto the intermediate processing tray. The discharged sheet falls in the lower right direction by its own weight along an intermediate processing tray (bundle discharge belt 503) provided obliquely. Further, when the fan-shaped return roller 504 rotates counterclockwise, the friction member provided on the arc of the return roller 504 contacts the sheet, and this friction member also acts to drop the sheet in the lower right direction. The end of the sheet is brought into contact with the stopper plate 507. As a result, the sheet is aligned in the vertical direction (feed direction).

  An alignment plate 506 is provided on the front side and the back side on the intermediate processing tray 503, and is driven each time a sheet is discharged onto the intermediate processing tray. (Alignment in the width direction) is performed. At this time, if the offset mode is set in the operation display unit 600, the sheet is offset in the width direction for each sheet bundle by the alignment plate 506. Details of the offset operation will be described later.

  When a predetermined number of sheets are discharged and stacked on the intermediate processing tray, the bundle discharge belt 503 is driven and discharged onto the stack tray 510 or 511. When the staple mode is set in the operation display unit 600, a bundle of sheets to be stapled is discharged onto the intermediate processing tray, and after the sheet aligning operation is performed by the alignment plate 506, the stapler is performed. A stapling operation is performed by driving 505, and the bundle is discharged onto the stack tray 510 or 511 by the bundle discharge belt 503.

Further, the stapler 505 can move in the lateral direction with respect to the sheet on the intermediate processing tray, and can perform a stapling operation at arbitrary positions on the near side and the far side. The operation display unit 600 sets the position where the stapling process is performed on the sheet.
(System block diagram)
Next, the configuration of a controller that controls the entire image forming apparatus will be described with reference to FIG. FIG. 2 is a block diagram showing a configuration of a controller that controls the entire image forming apparatus of FIG.

  As shown in FIG. 2, the controller includes a CPU circuit unit 150. The CPU circuit unit 150 includes a CPU (not shown), a ROM 151, and a RAM 152. Each block 480 is controlled by a control program stored in the ROM 151. 280, 281, 282, 283, 180, 680, and 580 are collectively controlled. The RAM 152 temporarily stores control data and is used as a work area for arithmetic processing associated with control.

  The document feeder control unit 480 controls driving of the document feeder 400 based on an instruction from the CPU circuit unit 150. The image reader control unit 280 performs drive control on the above-described scanner unit 202, the image sensor 203, and the like, and transfers the analog image signal output from the image sensor 203 to the image signal control unit 202.

  The image signal control unit 281 converts each analog image signal from the image sensor 203 into a digital signal, performs each process, converts the digital signal into a video signal, and outputs the video signal to the printer control unit 180. In addition, the digital image signal input from the computer 283 via the external I / F 282 is subjected to various processes, and the digital image signal is converted into a video signal and output to the printer control unit 180. The processing operation by the image signal control unit 281 is controlled by the CPU circuit unit 150. The printer control unit 180 drives the above-described exposure control unit 120 based on the input video signal.

  The operation display device control unit 680 exchanges information between the operation display unit 600 and the CPU circuit unit 150. The operation display unit 600 includes a plurality of keys for setting various functions related to image formation, various functions related to post-processing such as stapling and offset mode, a display unit 620 for displaying information indicating a setting state, and the like. A key signal corresponding to the key operation is output to the CPU circuit unit 150, and corresponding information is displayed on the display unit 620 based on the signal from the CPU circuit unit 150.

(Operation display section)
FIG. 5 is a diagram showing an operation display unit 600 in the image forming apparatus of FIG.

The operation display device 600 includes a start key 602 for starting an image forming operation, a stop key 603 for interrupting the image forming operation, ten keys 604 to 612 and 614 for setting numerical values, an ID key 613, and a clear key. 615, a reset key 616, and the like are arranged. In addition, a liquid crystal display unit 620 having a touch panel formed thereon is arranged, and a soft key can be created on the screen.
For example, the image forming apparatus according to the present embodiment has processing modes such as non-sort (group), sort, and staple sort (binding mode) as post-processing modes of the finisher 500. Setting such a processing mode is performed by an input operation from the operation display device 600.

(Stack tray)
Hereinafter, the operation of the stack tray will be described with reference to FIG. Stack trays 510 and 511 are trays on which sheets discharged from the intermediate tray 508 of the finisher 500 are stacked. Each of the stack trays 510 and 511 uses a motor (not shown) as a drive source, and performs a lifting operation. Further, a paper surface on the stack tray is detected by paper surface detection sensors 514 and 515 having a light emitting unit and a light receiving unit (not shown). Based on the input from the paper surface detection sensors 514 and 515, the stack tray is moved up and down to keep the paper surface position at an appropriate position. Also, sensors 512 and 513 detect the presence or absence of sheets on the stack trays 510 and 511, respectively. The stack trays 510 and 511 can stack up to 3000 sheets. Further, the number of stacked sheets on the stack tray is obtained by counting the number of discharged sheets. When the number of discharged sheets reaches the maximum number of stacked sheets in each stack tray (stack over), stacking on the stack tray is prohibited. Further, the number of stacked stack trays may be counted by weighting according to material, sheet basis weight, and the like.

  In a normal standby state, the paper surface of the stack tray 510 is positioned at the discharge port of the non-sort path 516, and the paper surface of the stack tray 511 is positioned at the discharge port of the intermediate tray 508. In the default setting, a non-sort job is discharged to the stack tray 510, and a job for post-processing such as stapling or sorting is discharged to the stack tray 511.

(Offset operation)
The sheet bundle offset operation will be described with reference to FIGS. When the sort mode is selected on the operation display unit 600, the alignment is performed on the intermediate tray 508 by the aligning plate 506 alternately in units of groups set by the user.

  The alignment plates 506a and 506b are slid in a direction orthogonal to the sheet conveying direction by a drive motor (not shown), respectively (FIG. 6). Home position sensors (not shown) are provided on the outermost sides of the slide movable range of the alignment plate 506, and the movement distances of the alignment plates 506a and 506b are managed based on the home position.

  In this configuration, the center of the tray coincides with the center of the sheet width that has been conveyed, and the center of the sheet is slid from the center to the left and right by a half of the shift amount, whereby the sheet is moved to the near side and the far side. Perform an offset.

  When the sheets are stacked on the intermediate tray 508, the alignment plates 506a and 506b are outside the sheet by a distance of 1/2 of the offset amount S when the sheets are stacked on the intermediate tray 508. Wait at the position (FIG. 7A). When the sheet P1 is conveyed to the intermediate tray 508 and the rear end portion of the sheet P1 is abutted against the stopper plate 507, the alignment plate 506b is driven toward the conveyance center side and pushes the rear end portion of the sheet P1 to the front side. Offset to Then, the offset is completed when the opposite end of the sheet P1 hits the alignment plate 506a (FIG. 7B). When a predetermined number of sheets are stacked on the intermediate tray, they are discharged to the stack tray.

  If the sheet P2 of the next sorting group is conveyed, the alignment plate 506a is driven to the conveyance center side, and the front end of the sheet P2 is pushed to be offset to the back side. The offset is completed when the opposite end of the sheet P2 hits the alignment plate 506b (FIG. 7C). When a predetermined number of sheets are stacked on the intermediate tray, they are discharged to the stack tray. FIG. 8 shows a state in which the offset sheet bundle is stacked on the stack tray.

  In this embodiment, the process starts from an offset toward the front side, but may start from an offset toward the back side. In this embodiment, the offset is performed on the intermediate tray 508 by using the alignment plate. However, the offset may be performed on the stack tray or the sheet conveyance path. Further, it may be performed by shifting the conveying roller without using the alignment plate.

(Offset amount control by selecting multiple sheets loading mode)
When the number of sheets stacked on the stack trays 510 and 511 is large, a multi-sheet stacking mode is set to perform stable stacking. The stack trays 510 and 511 are capable of stacking up to 3000 sheets in one tray. In this embodiment, a 3000-sheet stacking mode is performed in which 3000 sheets are stacked on one tray in order to stabilize the stackability.

  The 3000 sheet stacking mode is set from the display unit 620 (FIG. 9). When the “3000 sheet stacking” key, which is a soft key, is selected on the initial screen shown in FIG. 9, the 3000 sheet stacking mode is set.

  The flow of offset amount control in the first embodiment will be described with reference to FIG. The default offset amount is S1, the offset amount in the 3000-sheet stacking mode is S2, and S2 <S1. If the 3000 stacking mode is not set (S1002), S1 is selected as the offset amount (S1004). When the 3000 sheet stacking mode is set (S1002), S2 is selected as the offset amount S (S1003).

  After setting the offset amount S, the job is started, and the offset for each group and stacking on the stack trays 510 and 511 are repeatedly executed until the end of the job or stack over. FIG. 11 shows the stacking state on the stack tray at the normal offset (FIG. 11A) and at the 3000 sheet stacking mode (FIG. 11B).

[Second Embodiment]
(Offset amount control by detecting the number of sheets to be loaded)
The flow of offset amount control in the second embodiment will be described with reference to the flowchart of FIG. The default offset amount is S1, and the offset amount when the load amount exceeds the predetermined amount is S2, and S2 <S1.

  At the start of the job (S2001), when the original is fed by the original feeder 400 and the original is read by the scanner unit 201, the image supply controller 480 counts the number of pages of the original. Based on the counted number of document pages, the number of jobs input by the user on the operation display unit 600, and the image forming mode set by the user, the number of sheets to be stacked on the stack trays 510 and 511 is calculated (S2002).

  If the calculated estimated number of stacked sheets is equal to or less than the predetermined number (S2003), the default S1 is selected as the offset amount S (S2005). If the calculated estimated number of stacked sheets exceeds the predetermined number, S2 is selected as the offset amount S (S2004). The job is started with the set offset amount (S2006), the offset for each group is executed, and the stack trays 510 and 511 are stacked.

[Third embodiment]
(Shift amount control by the number of sheets ejected to the stack tray)
The offset amount control flow in the third embodiment will be described with reference to FIGS.

  In the present embodiment, the offset amount Sn is set to be changed based on the number of stacked sheets counted by the sheet stacking unit from the contents classified in advance in the lookup table as shown in FIG. When the paper detection sensors 512 and 513 on the stack trays 510 and 511 are OFF, the number of sheets discharged to the stack trays 510 and 511 is counted, and the number of sheets stacked on each stack tray is obtained.

  The flow of shift amount control based on the number of sheets discharged to the stack tray will be described with reference to the flowchart of FIG. If the paper detection sensor on the stack tray detects the absence of paper at the start of the job (S3001) (S3002), the variable n = 0 and the number of stacked sheets are set to 0, and the threshold value X0 of the number of stacked sheets and the offset are set from the lookup table. The quantity S0 is acquired (S3003). If there is paper (S3002), the data is not changed. If a job remains (S3004) and a sheet is discharged (S3005), the number of stacked sheets at the discharge destination is incremented (S3006). If the number of stacked sheets does not exceed Xn (S3007), the offset amount is not changed and the job is continued as it is.

  When the job is continued and the number of stacked sheets exceeds Xn (S3007), the offset amount Sn is changed with reference to the lookup table (S3008). Then, the variable n is incremented (S3009), and the process proceeds to S3004. Repeat until the end of the job or the occurrence of a stack over (S3004).

  FIG. 15 shows a sheet stacking state on the stack tray when the offset control is performed.

  In this embodiment, control is performed so that the offset amount is changed every 500 sheets in the lookup table, but control may be performed so that the offset amount is changed for each sheet bundle.

FIG. Block Diagram. Explanatory drawing of the image formation operation | movement at the time of face-up discharge | emission. Explanatory drawing of sheet | seat discharge operation | movement when post-processing is designated. Explanatory drawing of an offset means. Explanatory drawing of offset operation | movement. Explanatory drawing of the sheet | seat stacking | stacking on a stack tray at the time of offset mode setting. Explanatory drawing of stacking of an offset sheet bundle. Explanatory drawing of the display part at the time of multi-sheet loading mode setting. The flowchart of offset amount control in a 1st claim. Explanatory drawing of stacking of an offset bundle on a stack tray. The flowchart of offset amount control in a 2nd claim. Explanatory drawing of a lookup table. The flowchart of offset amount control in a 3rd claim. Explanatory drawing of stacking | stacking the offset bundle on the stack tray in a 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 100 Laser recording part (printer)
200 Image reader (reader)
400 Document feeder (ADF)
500 Post-processing equipment (finisher)
600 Display Operation Unit 501 Conveying Roller 502 Conveying Roller 503 Bundled Discharge Belt 504 Return Roller 505 Stapler 506 Alignment Plate 507 Stopper Plate 508 Intermediate Tray 510 Stack Tray 511 Stack Tray 512 Sheet Presence Sensor 513 Sheet Presence Sensor 514 Paper Surface Detection Sensor 515 Paper Surface Detection Sensor 515 Sensor 516 Non-sort paper discharge path 517 Transport roller 518 Flapper 519 Sort paper discharge path 520 Buffer roller 521 Flapper 620 Display unit

Claims (5)

Sheet stacking means for stacking discharged sheets;
Offset means for shifting the sheet in a direction perpendicular to the conveying direction;
Offset mode setting means for setting an offset mode for stacking sheets on the sheet stacking means in a state where sheets are alternately shifted by the offset means for every predetermined number of sheets;
In the offset means, an offset amount control means for controlling the offset amount;
A scheduled number of sheets detection means for detecting the number of sheets stacked on the sheet stacking means before the start of the job,
When the offset mode is set by the offset mode setting unit, if the number of stacked sheets on the sheet stacking unit detected by the planned stacking number detection unit before starting the job exceeds a predetermined number, the offset amount control unit A sheet processing apparatus that performs control so as to change a sheet offset amount and stacks sheets on the sheet stacking unit.   When the offset mode is set by the offset mode setting means, if the number of stacked sheets on the sheet stacking means detected by the planned stacking number detecting means before starting the job exceeds a predetermined number, the offset amount control means 2. The sheet processing apparatus according to claim 1, wherein the sheet is stacked on the sheet stacking unit by controlling so as to reduce the offset amount. A loading amount designation mode setting means for setting a loading amount designation mode for designating a sheet loading amount to the sheet loading means;
3. The sheet according to claim 1, wherein the scheduled number of sheets detection unit detects the number of sheets to be discharged to the sheet post-processing apparatus from the presence / absence of the setting of the loading amount designation mode in the loading amount designation mode setting unit. Processing equipment. It has an automatic document feeder that automatically reads documents continuously,
The scheduled number of sheets detection means discharges the sheet from the number of pages of the document read by the automatic document feeder, the number set by the user, and the number of documents detected by the document number detection means to the sheet post-processing device. 3. The sheet processing apparatus according to claim 1, wherein the number of sheets to be detected is detected. Sheet stacking means for stacking discharged sheets;
Offset means for shifting the sheet in a direction perpendicular to the conveying direction;
Offset mode setting means for setting an offset mode for stacking sheets on the sheet stacking means in a state where sheets are alternately shifted by the offset means for every predetermined number of sheets;
In the offset means, an offset amount control means for controlling the offset amount;
Detecting means for detecting the number of discharged sheets to the sheet stacking means,
When the offset mode is set by the offset mode setting unit, the offset amount is controlled by the offset amount control unit every time the detection unit detects a predetermined number of sheets discharged to the sheet stacking unit. A sheet processing apparatus that stacks sheets on the sheet stacking unit.

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