JP2015157477A - Sheet process device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect the timing when constant press force is applied to a sheet bundle in a binding process without reference to the number of sheets nor a type of paper of the sheet bundle.SOLUTION: A sheet process device includes: a staple-less binding device 52 which performs a binding process by pressing a sheet bundle S; a staple-less binding motor 75 which drives the staple-less binding device 52 so as to press the sheet bundle S; an encoder sensor 90 which detects the speed of the staple-less binding motor 75; and a CPU 162 which brakes the staple-less binding motor 75 when the speed detected by the encoder sensor 90 decreases below a predetermined speed in a period in which the staple-less binding device 52 presses the sheet bundle S.

Description

  The present invention relates to a sheet processing apparatus and an image forming apparatus having a binding processing function.

  2. Description of the Related Art Conventionally, as a device for binding sheets on which images are formed by an image forming apparatus such as a copying machine or a printer, a stapling device that performs a binding process of binding a sheet bundle composed of a plurality of sheets using a binding member such as a metal needle. Widely used. When each sheet of the sheet bundle that has been stapled by the stapler is used as a reading document, it is necessary to remove the needle that binds the sheet bundle. Also, when recycling a sheet bundle that has been bound with a needle, from the viewpoint of environmental protection, it is necessary to remove the needle that is binding the sheet bundle and separate and collect the sheet and the needle. Since the needle used for the binding process is discarded after use, there is a problem from the viewpoint of resource reuse.

  In view of this, a sheet binding apparatus has been provided that does not use a binding member such as a needle or the like and reduces the trouble of reusing or recycling as a document (for example, see Patent Document 1). In such a sheet binding apparatus, since the needle is not used, the needle is not discarded. In this sheet binding apparatus, a plurality of sheets conveyed from the image forming apparatus are bundled and aligned to form a sheet bundle, and then a tooth mold having a convex portion and a concave portion that form irregularities on a part of the sheet bundle is formed on the sheet. It is the structure pressed against. The sheet binding apparatus performs binding processing by entwining the fibers of the sheet bundle by pressing the sheet bundle in this way.

JP 2004-155537 A

  When the above-described conventional needleless binding method is applied to an image forming apparatus, a configuration in which a pressing operation is automated using an actuator as a driving source that presses a tooth mold having a convex portion and a concave portion against a sheet bundle is assumed. . In the stapleless binding process, a constant pressing force is applied to the sheet bundle in order to maintain the binding force of the binding unit and to prevent the binding unit from being broken in maintaining the quality of the sheet bundle after the binding process. It is important to give a stable. For this purpose, it is necessary to accurately detect the timing at which a constant pressing force is applied to the sheet bundle.

  However, since the thickness of the sheet bundle and the density of the sheet vary depending on the number of sheets and the paper type, the timing at which a constant pressing force is applied to the sheet bundle is not constant. For this reason, unless the period during which a constant pressing force is applied to the sheet bundle is not appropriate, a phenomenon that the sheet bundle easily peels (hereinafter referred to as binding failure) occurs, or excessive pressure is applied to the sheet bundle and the sheet is There is a risk of tearing.

  The present invention has been made under such circumstances, and in the binding process, accurately detects the timing at which a constant pressing force is applied to the sheet bundle regardless of the number of sheet bundles and the paper type. Objective.

  In order to solve the above-described problems, the present invention has the following configuration.

  (1) A binding unit that performs a binding process by pressing a sheet bundle, a motor that drives the binding unit to press the sheet bundle, a speed detection unit that detects a speed of the motor, and the binding unit And a control unit that applies a brake to the motor when a speed detected by the speed detection unit becomes equal to or lower than a predetermined speed during a period in which the sheet bundle is being pressed.

  (2) an image forming unit that forms an image on a sheet; a stacking unit on which sheets formed by the image forming unit are stacked; and the sheet processing apparatus according to (1), wherein the sheet processing is performed. The apparatus performs the binding process by pressing a sheet bundle composed of a plurality of sheets stacked on the stacking unit.

  According to the present invention, it is possible to accurately detect the timing at which a constant pressing force is applied to a sheet bundle regardless of the number of sheet bundles and the paper type in the binding process.

1 is a diagram illustrating a configuration of an image forming apparatus and a sheet processing apparatus according to an embodiment. The figure which shows the structure of the staple-less binding apparatus of embodiment. Block diagram of an image forming apparatus and a sheet processing apparatus according to an embodiment 7 is a flowchart illustrating processing on the image forming apparatus side and the sheet processing apparatus side according to the embodiment. Flowchart showing stapleless binding processing of the sheet processing apparatus according to the embodiment The figure which shows the operation | movement timing chart at the time of the staple-less binding process of embodiment The figure which shows the output torque characteristic of embodiment, the figure which shows the measurement timing

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

(Image forming device)
FIG. 1A is a schematic cross-sectional view of an image forming apparatus and a sheet processing apparatus as an image forming system according to an embodiment. FIG. 1A is a view when the front surface (front surface) of the image forming apparatus 1 is in front. The image forming apparatus 1 includes an image reading unit 2, an image forming unit 3, and a sheet processing device 50. A user sets a job to the image forming apparatus 1 from the operation unit 40 or from an external device such as a personal computer (hereinafter referred to as a PC) via a network. If the set job is a copying operation, image forming processing and post-sheet processing are performed based on the image data from the image reading unit 2 and if it is a printing operation, based on the image data transmitted from the PC via the network.

  The image reading unit 2 will be described. A document table 4 made of a transparent glass plate fixedly provided is provided above the image reading unit 2. The document D is placed at a predetermined position on the document table 4 with the image surface facing downward, and is pressed and fixed by the document table cover 5. An optical system comprising a lamp 6 that illuminates the document D, and reflecting mirrors 8, 9, and 10 for guiding a light image of the illuminated document D to an image processing unit 7 having an image sensor on the lower side of the document table 4. Is provided. The lamp 6 and the reflecting mirrors 8, 9, 10 move at a predetermined speed to scan the document D and transmit image data to the image forming unit 3.

  The image forming unit 3 includes a photosensitive drum 11, a primary charging roller 12, a rotary developing unit 13, an intermediate transfer belt 14, a transfer roller 15, a cleaner 16, and the like. The photosensitive drum 11 is irradiated with laser light from the laser unit 17 based on the image data, and an electrostatic latent image is formed on the surface of the photosensitive drum 11. The primary charging roller 12 uniformly charges the surface of the photosensitive drum 11 before laser beam irradiation. The rotary developing unit 13 forms magenta (M), cyan (C), yellow (Y), and black (K) toners on the electrostatic latent image formed on the surface of the photosensitive drum 11 to form a toner image. To do. Hereinafter, when a color is specified, it is described by adding symbols M, C, Y, and K to the code. The toner image developed on the surface of the photosensitive drum 11 is transferred to the intermediate transfer belt 14, and the toner image on the intermediate transfer belt 14 is transferred onto the sheet P by the transfer roller 15 at the transfer position. The cleaner 16 removes the toner remaining on the photosensitive drum 11 after transferring the toner image.

  The toner image developed on the photosensitive drum 11 by the rotary developing unit 13 is transferred to the intermediate transfer belt 14. The toner image on the intermediate transfer belt 14 is transferred to the sheet P by the transfer roller 15. The sheet P is supplied from the paper cassette 18a. Further, the sheet P may be supplied from the manual feed tray 18b. A fixing device 19 is provided on the downstream side (hereinafter, simply referred to as the downstream side) of the image forming unit 3 in the conveyance direction of the sheet P. The fixing device 19 performs a fixing process on the toner image on the conveyed sheet P. I do. The sheet P on which the toner image is fixed in the fixing device 19 is discharged from the image forming apparatus 1 to the downstream sheet processing apparatus 50 by the discharge roller pair 21. A portion where the sheet P is discharged by the discharge roller pair 21 is referred to as a paper discharge portion.

(Sheet processing equipment)
Next, the sheet processing apparatus 50 will be described. As illustrated in FIG. 1A, the sheet processing apparatus 50 is provided in a paper discharge unit of the image forming apparatus 1 and communicates with the image forming apparatus 1 through a signal line (not shown), whereby the image forming apparatus 1. Operates in cooperation with. Here, FIG. 1B is a view of the sheet processing apparatus 50 as viewed from above with the image reading unit 2 removed, and a part of the members shown in FIG. Yes. Also, the lower side in FIG. 1B is the front side (front side) of the image forming apparatus 1 shown in FIG. Further, the thick black arrow in FIG. 1B indicates the conveyance direction after the binding process of the sheet bundle S indicated by a broken line.

  The sheet processing apparatus 50 binds a plurality of sheets P discharged from the image forming apparatus 1 to form a sheet bundle S, and binds the fibers of the sheet bundle S by entwining each other without using a binding member such as a needle. It has a needleless binding device 52 that performs processing. The needleless binding device 52 forms a tooth pattern (upper teeth 97 and lower teeth 98, see FIG. 2) having convex portions and concave portions provided to face each other to form embossed irregularities on a part of the sheet bundle S. I have. The stapleless binding device 52 bundles and aligns a plurality of sheets P conveyed from the image forming apparatus 1 to form a sheet bundle S, and then the sheet bundle S inserted between the convex and concave tooth molds. Pinch. Then, the stapleless binding device 52 presses the tooth mold against the sheet bundle S sandwiched between the convex and concave tooth molds and entangles the fibers of the sheet bundle S to perform the binding process. Do. Hereinafter, a binding process in which binding is performed by intertwining the fibers of the sheet bundle S without using a binding member such as a needle is referred to as a “needleless binding” process.

  After the sheet processing apparatus 50 receives the sheet P discharged from the image forming apparatus 1 by the conveyance unit 58, the sheet processing apparatus 50 performs accelerated conveyance that accelerates the conveyance speed of the sheet P more than the conveyance speed in the image forming apparatus 1. Then, after the sheet P is transported from the transport unit 58, the sheet processing apparatus 50 rotates the paddle roller 59 to stack the sheets P on the processing tray 57. The sheet processing apparatus 50 further performs rear end alignment processing for aligning the rear ends of a plurality of sheets P stacked by abutting the rear end of the sheet P against the rear end alignment plate 62 by the return roller 60.

  The paper sensor 56 is a sensor that detects the presence or absence of the sheet P on the processing tray 57. The sheet bundle S composed of a plurality of sheets P subjected to rear end alignment processing in the processing tray 57 is aligned on the sheet width direction by the alignment plates 64 and 65 and stacked on the processing tray 57. The sheet width direction is a direction orthogonal to the sheet P conveyance direction. The sheet processing apparatus 50 repeats these series of operations. In a job for which stapleless binding processing is designated, after the designated number of sheets P are stacked on the processing tray 57, the stapleless binding device 52 performs the binding processing at the position shown in FIG. That is, the stapleless binding device 52 performs a binding process on one side of the corner of the rear end of the sheet bundle S. Note that the position where the stapleless binding process is performed is not limited to the position shown in FIG. After the binding processing by the stapleless binding device 52 is completed, the sheet bundle S is discharged to the paper discharge tray 63 along the bottom surface of the processing tray 57 so that the rear end side of the sheet bundle S is pushed out by the bundle pushing member 61. .

(Needleless binding device)
A detailed configuration of the needleless binding device 52 will be described with reference to FIG. FIG. 2A shows a standby state in which the stapleless binding device 52 is not performing a binding operation, and FIG. 2B shows a binding operation state. In the needleless binding device 52, an output shaft of a needleless binding motor 75 (hereinafter simply referred to as a motor) (denoted as M in the figure) is connected to a cam rotation shaft 94 via a speed reduction mechanism 91 formed of a gear. . In the present embodiment, the motor 75 uses a DC brush motor. The output shaft of the motor 75 is provided with an encoder sensor 90 that is a speed detecting means for measuring a rotational speed that is the rotational speed per unit time. The encoder sensor 90 is an optical sensor, detects a slit provided in a disk on the output shaft of the motor 75, and outputs a pulse signal whose cycle varies according to the rotational speed of the motor 75. That is, the CPU 162 (see FIG. 3) described later can detect the rotational speed of the motor 75 based on the pulse signal input from the encoder sensor 90. In the present embodiment, the disk provided on the output shaft of the motor 75 has a slit number of 18 slits / periphery.

  The cam 92 operates the upper arm 95 via the roller 93 by the rotation of the cam rotation shaft 94. An upper tooth 97 that is a first pressing portion that presses one surface of the sheet bundle S is attached to the upper arm 95, and the upper arm 95 swings around the arm shaft 96. The lower arm 99 is fixed to the housing frame of the sheet processing apparatus 50. The lower arm 99 is provided to face the upper teeth 97, and a second press that presses the other surface of the sheet bundle S. The lower tooth 98 which is a part is attached. In addition, although the convex part of the tooth type mentioned above and a recessed part respond | correspond to the upper tooth 97 and the lower tooth 98, which may be a convex part or a recessed part. In this embodiment, the lower arm 99 is fixed to the housing frame of the sheet processing apparatus 50, but the upper arm 95 may be fixed to the housing frame. Further, the upper arm 95 and the lower arm 99 may be configured not to be fixed to the housing frame.

  The lower teeth 98 attached to the lower arm 99 and the upper teeth 97 attached to the upper arm 95 mesh with each other with the sheet bundle S interposed therebetween, and pressurize the sheet bundle S. The surface of each sheet P of the pressed sheet bundle S is stretched by the meshed upper teeth 97 and lower teeth 98 to expose the fibers. Further, when the upper teeth 97 and the lower teeth 98 are further pressurized, the fibers of the sheets P are intertwined with each other, and the sheet bundle S is fastened. For this reason, the sheet bundle S can be fastened without using a binding member such as a staple.

  When the sheet bundle S is stacked on the processing tray 57, the cam 92 is at the position shown in FIG. When the cam 92 is located at the bottom dead center, the reference sensor 76 detects the upper arm 95. The reference sensor 76 outputs an ON signal to the CPU 162 when the upper arm 95 is detected. That is, the state where the cam 92 shown in FIG. 2A is at the bottom dead center is the state before the motor 75 starts driving (initial state). As shown in FIG. 2A, when the cam 92 is located at the bottom dead center, a space is formed between the upper teeth 97 and the lower teeth 98, and the sheet bundle S can enter the space. The cam 92 has, for example, a droplet shape, and is applied to the motor 75 even when the motor 75 drives the cam 92 while the roller 93 is in contact with the Z portion (thick line portion) shown in FIG. The load is small enough to be ignored. The shape of the cam 92 may be configured so that the motor 75 is not loaded while the roller 93 is in contact with the Z portion. The Z portion is a region along a predetermined ridge line distance (a thick line portion in FIG. 2A) on the outer periphery of the cam 92 from the bottom dead center of the cam 92. When the motor 75 starts driving the cam 92, the cam rotation shaft 94 rotates in the X direction (counterclockwise direction). As the cam 92 rotates, the upper arm 95 starts to move, and the reference sensor 76 does not detect the upper arm 95. However, while the roller 93 is in contact with the Z portion, the load applied to the motor 75 is negligible. During the period when the roller 93 is in contact with the Z portion, the upper teeth 97 do not press the sheet bundle S. Thus, the Z portion of the cam 92 has a shape in which the load on the motor 75 is very small, and the torque of the motor 75 is configured to be substantially unloaded via the speed reduction mechanism 91.

  The binding operation of the needleless binding device 52 is started, and the cam 92 is further rotated in the X direction around the cam rotation shaft 94 by the drive of the motor 75. As described above, when the cam rotation shaft 94 of the cam 92 continues to rotate in the X direction, the contact portion between the roller 93 and the cam 92 is removed from the region of the Z portion, and the load applied to the motor 75 increases. When the positional relationship is as shown in FIG. 2B, the upper teeth 97 and the lower teeth 98 mesh. When the cam 92 is at the position shown in FIG. 2B, this position is set as the top dead center. At this time, the pressure generated between the upper teeth 97 and the lower teeth 98 is controlled so as to mesh at a predetermined pressure by adjusting the drive current of the motor 75. Thereafter, when the motor 75 rotates in the Y direction (clockwise direction) around the cam rotation shaft 94 and the cam 92 reaches the bottom dead center shown in FIG. Is detected. When the CPU 162 described later detects the upper arm 95 by the reference sensor 76, the driving of the motor 75 is stopped, and the cam 92 stops rotating.

(Control block of image forming apparatus and sheet processing apparatus)
Next, control blocks of the image forming apparatus 1 having the sheet processing apparatus 50 shown in FIG. 1A will be described with reference to FIG. The image forming apparatus 1 includes a CPU 161 that controls the image forming apparatus 1, a ROM 165, a RAM 166, and an operation unit 40. The ROM 165 stores programs, data, and the like for controlling the image forming apparatus 1. The RAM 166 is used to read / write processing data when the CPU 161 controls the image forming apparatus 1. The operation unit 40 receives setting of a post-processing method by the image forming apparatus 1 and the sheet processing apparatus 50 from the user. In the present embodiment, it is possible to select execution of the stapleless binding process as the post-processing method. The CPU 161 can recognize information set by the user operating the operation unit 40 (also referred to as setting information) by communicating with the operation unit 40. On the other hand, the sheet processing apparatus 50 includes a CPU 162, a ROM 167, and a RAM 168 that are control means for controlling the sheet processing apparatus 50. The CPU 162 can detect each other's state by communicating with the CPU 161 of the image forming apparatus 1. The ROM 167 stores programs, data, and the like for controlling the sheet processing apparatus 50. The RAM 168 is used to read / write processing data when the CPU 162 controls the sheet processing apparatus 50.

  The motor 75, the encoder sensor 90, and the reference sensor 76 are provided in the needleless binding device 52 (see FIG. 2). The reference sensor 76 detects when the upper arm 95 is at the receiving position of the sheet bundle S (state in FIG. 2A) as a reference position, and notifies the CPU 162 that the upper arm 95 has been detected. The CPU 162 detects whether or not the upper arm 95 is at the reference position by the reference sensor 76. The CPU 162 outputs a motor drive signal to the drive circuit 82, thereby controlling the drive / stop of the motor 75 via the drive circuit 82 and performing the binding process by the needleless binding device 52. Further, the CPU 162 can instruct the rotation direction of the motor 75 when controlling the driving of the motor 75. The drive voltage V is input to the drive circuit 82 and is used as a power source for driving the motor 75. The drive voltage V is converted into a voltage level by the conversion circuit 102 and then input to the CPU 162 as the voltage Vm. The CPU 162 detects the voltage level of the drive voltage V based on the input voltage Vm. That is, the CPU 162 also functions as a voltage detection unit. The shunt resistor R1 is inserted between the drive circuit 82 and the ground, and is used for detecting the drive current I of the motor 75.

  The current limiting circuit 100 has a comparator, and compares the limit current signal input from the CPU 162 with a voltage corresponding to the current flowing through the shunt resistor R1. The current flowing through the shunt resistor R1 is the drive current I of the motor 75. The limit current signal input from the CPU 162 is an analog variable voltage signal, and is a signal for maintaining the drive current I of the motor 75 at a predetermined value for a predetermined time. Here, the predetermined time is a time corresponding to a time required for fastening the sheets in the sheet bundle S pressed by the upper teeth 97 and the lower teeth 98. The current limiting circuit 100 compares the voltage signal from the shunt resistor R1 and the limit current signal, and controls the drive circuit 82 so that the drive current I of the motor 75 becomes a predetermined value corresponding to the limit current signal.

  When the motor 75 is driven, a pulse signal having a frequency proportional to the rotation speed of the motor 75 is input to the CPU 162 by the encoder sensor 90. The CPU 162 calculates the rotation speed of the motor 75 by measuring the edge interval of the pulse signal input from the encoder sensor 90 with a timer (not shown).

(Processing on the image forming apparatus side)
A stapleless binding control sequence using the stapleless binding device 52 of the sheet processing apparatus 50 according to job information (hereinafter referred to as job information) from the image forming apparatus 1 will be described. 4A is a flowchart of control executed by the CPU 161 of the image forming apparatus 1, and FIG. 4B is a flowchart of control executed by the CPU 162 of the sheet processing apparatus 50.

  When power is supplied to the image forming apparatus 1 (power on), the CPU 161 of the image forming apparatus 1 starts the following control. In step (hereinafter referred to as “S”) 501, the CPU 161 performs the initialization operation, and then places the image forming apparatus 1 in a standby state and waits. Here, the standby state is a state in which a job is waiting to receive a job from the operation unit 40 or an external device, and an image forming operation can be immediately executed when a job is received. In step S502, the CPU 161 determines whether a job has been received via the operation unit 40 or the network. If the CPU 161 determines in S502 that the job has not been received, the process returns to S501. That is, the CPU 161 continues in the standby state until a job is received. Note that when the state in which no job is received continues for a certain period of time, the image forming apparatus 1 and the sheet processing apparatus 50 may be shifted from the standby state to the power saving state.

  If the CPU 161 determines in S502 that the job has been received, in S503, the CPU 161 notifies the CPU 162 in the sheet processing apparatus 50 of the received job information, and receives a reception waiting time corresponding to the job information from the CPU 162. Here, the reception waiting time is a predetermined time required until the sheet processing apparatus 50 can start the post-processing operation when receiving the sheet P from the image forming apparatus 1. The CPU 161 resets and starts a timer (not shown). In S504, the CPU 161 determines whether or not the reception standby time received from the CPU 162 in S503 has elapsed by referring to a timer (not shown). If the CPU 161 determines in S504 that the reception standby time has not elapsed, it repeats the processing in S504. If the CPU 161 determines in S504 that the reception standby time has elapsed, the process proceeds to S505. In step S505, the CPU 161 feeds the sheet P from the paper cassette 18a, transports the sheet P on the transport path, and waits the sheet P at a registration position that is a standby position for timing the image transfer to the sheet P. . In step S506, the CPU 161 performs an image forming operation, and resumes the conveyance of the sheet P from the registration position in synchronization with the image formation timing. That is, the toner image is transferred onto the sheet P at the transfer position, and after the unfixed toner image is fixed on the sheet P by the fixing device 19, the sheet P is discharged to the sheet processing apparatus 50.

  In step S507, the CPU 161 determines whether the predetermined number of sheets has been completed (job completion) according to the job information. If the CPU 161 determines that the job has not been completed, the process returns to step S505. If the CPU 161 determines in S507 that the job has been completed, it determines in S508 whether or not there is a next job, that is, accepts the next job and determines whether or not the next job is waiting. If the CPU 161 determines in S508 that there is a next job, the process returns to S503, and if it is determined that there is no next job, the process returns to S501.

(Processing on the sheet processing device side)
Next, a control flowchart of the CPU 162 of the sheet processing apparatus 50 will be described with reference to FIG. When the image forming apparatus 1 is turned on, power is supplied from the image forming apparatus 1 to the sheet processing apparatus 50 (power on). When power is supplied, the CPU 162 is activated, and the CPU 162 starts the processing from S601. In step S <b> 601, the CPU 162 waits in a standby state after performing the initialization operation of the sheet processing apparatus 50. In step S <b> 602, the CPU 162 determines whether job information is notified from the CPU 161 of the image forming apparatus 1 (job information is accepted). If the CPU 162 determines in S602 that job information has not been received, the process returns to S601. If the CPU 162 determines in S602 that the job information has been received, the process proceeds to S603. In step S <b> 603, the CPU 162 notifies the CPU 161 of the image forming apparatus 1 of a predetermined reception waiting time until the sheet processing apparatus 50 can receive the sheet P from the image forming apparatus 1 according to the job information received from the CPU 161. . Note that the processing on the CPU 161 side of the image forming apparatus 1 corresponds to the processing of S503 in FIG.

  In step S <b> 604, the CPU 162 receives the sheet P when the sheet P on which image formation has been completed in the image forming apparatus 1 is discharged, and performs a post-processing operation by the sheet processing apparatus 50. Here, the post-processing operation performed by the sheet processing apparatus 50 is as follows. The CPU 162 accelerates the conveyance speed of the sheet P by the conveyance unit 58 and then conveys the sheet P to drive and rotate the paddle roller 59 to scrape the sheet P into the processing tray 57. Then, the CPU 162 conveys the plurality of sheets P on the processing tray 57 so as to abut against the rear end alignment plate 62 by the return roller 60, and performs a rear end alignment operation for aligning the rear ends of the plurality of sheets P. Further, after performing the trailing edge alignment operation, the CPU 162 aligns the positions of the plurality of sheets P in the sheet width direction by the alignment plates 64 and 65 and stacks them on the processing tray 57.

  In S605, the CPU 162 determines whether or not the number of sheets P designated by the job has been stacked on the processing tray 57. If it is determined that the sheets are not stacked, the process returns to S604. The CPU 162 counts the number of sheets discharged to the processing tray 57 by a sensor (not shown) provided on the conveyance path, and determines whether or not the designated number of sheets P are stacked based on the count value. to decide. This sensor may be provided on the conveyance path of either the image forming apparatus 1 or the sheet processing apparatus 50. If the CPU 162 determines in step S605 that the number of sheets P specified by the job has been stacked on the processing tray 57, the process proceeds to step S606. In step S606, the CPU 162 determines whether the needleless binding process is designated based on the received job information. If the CPU 162 determines that the needleless binding process is not designated, the process proceeds to step S608. If the CPU 162 determines that the needleless binding process is designated in S606, the CPU 162 executes the needleless binding process in S607. The needleless binding process performed in S607 will be described later with reference to FIG. In S <b> 608, the CPU 162 pushes out the rear end side of the sheet bundle S stacked on the processing tray 57 by the bundling member 61 and discharges it to the paper discharge tray 63. In S609, the CPU 162 determines whether or not the specified post-processing operation for the specified number of copies has been completed (hereinafter referred to as job completion) based on the job information. If the CPU 162 determines that the job has not been completed, the process proceeds to S604. Return to the process. If the CPU 162 determines in step S609 that the job has been completed, the process returns to step S601.

(Needleless binding process)
Next, the stapleless binding process performed by the CPU 162 of the sheet processing apparatus 50 will be described with reference to the flowchart of FIG. FIG. 6 is a time chart showing signals at various parts of the sheet processing apparatus 50 during the stapleless binding process. Here, FIG. 6A shows the position of the cam 92 described in FIG. 2, such as “bottom dead center” and “binding operation point (top dead center)”. A signal (b) in FIG. 6 indicates a motor drive signal of the motor 75. In signal (b), CW (clockwise) is forward rotation, BRAKE is rotation stop, CCW (counter clockwise) is reverse rotation, and STOP is drive stop. Show. Thus, in this embodiment, CW is assumed to be normal rotation and CCW is assumed to be reverse rotation. The waveform (c) in FIG. 6 shows the waveform of the drive current I [A] of the motor 75. The current value corresponding to the predetermined value Ia stored in the RAM 168 is A1, and the limit current value is IL. It is indicated by a broken line. A waveform (d) in FIG. 6 shows a waveform of the drive voltage V [V] for driving the motor 75. A waveform (e) in FIG. 6 indicates the number of revolutions [rps] per unit time (second) of the motor 75 detected by the encoder sensor 90. In the waveform (e) in FIG. 6, predetermined rotation speeds X and Y, which will be described later, are indicated by alternate long and short dash lines. A waveform (f) in FIG. 6 shows a limit current signal [V] output from the CPU 162 to the current limiting circuit 100, and a waveform (g) in FIG. 6 shows a detection signal [V] output from the reference sensor 76 to the CPU 162. ] Is shown. The horizontal axis in FIG. 6 is time.

  The CPU 162 executes the stapleless binding process in S607 of FIG. In S701 in FIG. 5, the CPU 162 outputs a motor drive signal to the drive circuit 82 to drive the motor 75 in the forward rotation (CW) direction in order to perform the needleless binding process. The CPU 162 drives the motor 75 in the normal rotation direction to rotate the cam 92 in the X direction (counterclockwise direction) from the bottom dead center as shown in FIG. Here, in the present embodiment, when the CPU 162 starts driving the motor 75 by the driving circuit 82, the motor 75 is driven with the current value corresponding to the limit current signal Ia set in S701 as the driving current I of the motor 75. To do. Further, the CPU 162 resets and starts a timer (not shown). In S <b> 702, the CPU 162 stands by (waits) the measurement of the driving voltage and the rotation speed of the motor 75 during the measurement mask time T <b> 1 by referring to a timer (not shown). The process of S702 is executed in order to exclude from the measurement target a period in which the drive voltage and rotation speed of the motor 75 vary due to the inertial load of the speed reduction mechanism 91 immediately after the start of driving. As shown in waveforms (c) and (e) of FIG. 6, the drive current I and the output from the encoder sensor 90 are not stable during the measurement mask time T1. The measurement mask time T <b> 1 is a fixed value or a value indicating a time during which measurement determined for each needleless binding apparatus is not performed, and is stored in advance in the ROM 167.

  In step S <b> 703, the CPU 162 measures the voltage Vm obtained by converting the drive voltage V for driving the motor 75 by the conversion circuit 102 a plurality of times. Since the drive voltage V fluctuates not a little, in this embodiment, the measurement accuracy is improved by averaging the voltage Vm measured a plurality of times. Further, the CPU 162 calculates the rotational speed of the motor 75 by measuring the edge interval (that is, corresponding to the period) of the pulse signal input from the encoder sensor 90 a plurality of times and averaging it. The time for the CPU 162 to perform these measurements is a measurement time T2. The measurement time T2 is longer than the difference between the measurement mask time T1 and the time during which the contact portion between the roller 93 and the cam 92 moves along the Z portion of the cam 92 shown in FIG. It is set not to be. Hereinafter, the time during which the roller 93 moves in the Z portion of the cam 92 is referred to as a movement period. The measurement time T2 is set to be within the time obtained by subtracting the measurement mask time T1 from the movement period. In other words, the measurement time T2 is set so that the current is measured within a no-load period in which the motor 75 is hardly loaded. That is, current measurement is performed during a period when the motor 75 is being driven and the upper teeth 97 are not pressing the sheet bundle S. The measurement time T2 is stored in the ROM 167. The predetermined ridge line distance (Z portion) that defines the no-load section is a fixed value or a value set according to the shape of the cam 92. Thus, the CPU 162 measures the voltage Vm corresponding to the drive voltage V for driving the motor 75 and the cycle of the pulse signal from the encoder sensor 90 within the measurement time T2. Note that the CPU 162 resets and starts a timer (not shown), and measures the measurement time T2 by referring to the timer. As shown in the waveforms (c) and (e) of FIG. 6, the drive current I and the output from the encoder sensor 90 are stable during the measurement time T2.

(Determination of motor rotation speed and torque constant Kt)
Hereinafter, the determination of the rotational speed Nm of the motor 75 and the torque constant Kt by the CPU 162 will be described in detail. CPU162 calculates | requires the average value of the voltage Vm according to the drive voltage V measured several times. The CPU 162 converts the average value of the voltage Vm into the driving voltage V of the motor 75 using data (Table 1) indicating the relationship between the voltage Vm and the motor driving voltage V stored in advance in the ROM 167. In Table 1, the average value of the voltage Vm [V] is described in the left column, and the drive voltage V [V] of the motor 75 converted from the average value of the voltage Vm is described in the right column. For example, when the average value of the voltage Vm is 1.35V, the CPU 162 converts the drive voltage V of the motor 75 to 22.89V.

Further, the CPU 162 averages the result of measuring the cycle of the pulse signal from the encoder sensor 90 a plurality of times, and calculates the average value Te. Then, the CPU 162 uses the following formulas (1) and (2) prepared in advance to calculate the rotation angular velocity ωm (rotation angle per unit time) and the rotation speed Nm (rotation per unit time) from the average value Te. Number).
ωm = 2 × π × (1 ÷ Te [sec]) ÷ 18 (1)
Nm = (1 ÷ Te) ÷ 18 (2)
Each unit system is ωm [rad / sec], Te [sec], and Nm [rps]. The numerical value 18 in the formula is the number of slits provided in the disk on the output shaft of the motor 75.

  In S <b> 704, the CPU 162 determines whether or not the calculated rotation speed Nm is greater than a predetermined rotation speed Y stored in advance in the ROM 167. If the CPU 162 determines in step S704 that the rotational speed Nm calculated in step S703 is equal to or lower than the predetermined rotational speed Y (Nm ≦ Y), the CPU 162 determines that the rotational speed of the motor 75 is not in a normal state, and proceeds to the processing in step S715. . Here, the predetermined rotational speed Y is a value determined from the rotational speed characteristics of the motor 75 and the lower limit value of the rotational speed including the environment in which the apparatus is installed, the usage time and usage frequency of the apparatus, and the like. Then, for example, Y = 70 [rps] is set (see FIG. 6E). In S715, the CPU 162 notifies the CPU 161 of the image forming apparatus 1 of a motor error as an abnormality of the motor 75, and proceeds to the process of S713. As described above, the CPU 162 detects that the rotation speed of the motor 75 detected by the encoder sensor 90 is equal to or lower than the predetermined rotation speed after the measurement mask time T1 and the measurement time T2 have elapsed since the start of the driving of the motor 75. First, the drive of the motor 75 is stopped.

  On the other hand, if the CPU 162 determines that the rotational speed Nm of the needleless binding motor 75 is greater than the predetermined rotational speed Y (Nm> Y) in S704, the CPU 162 determines that the needleless binding motor 75 is rotating in the normal range. , The process proceeds to S705. As described above, when the measurement mask time T <b> 1 and the measurement time T <b> 2 have elapsed since the start of driving of the motor 75, the CPU 162 detects that the rotation speed of the motor 75 detected by the encoder sensor 90 is greater than a predetermined rotation speed. To continue the binding process. In the present embodiment, when the motor 75 is normally driven, the rotation speed of the motor 75 is 90 rps (see FIG. 7B). In S705, the CPU 162 determines the torque constant Kt based on the cycle of the pulse signal from the encoder sensor 90 measured in S703 and the voltage Vm corresponding to the drive voltage V of the motor 75. That is, the CPU 162 also functions as a control unit that determines the drive current of the motor.

Here, the torque constant Kt of the motor 75 is determined. FIG. 7A is a graph showing the relationship between the drive current and the output torque, where the horizontal axis is the drive current I [A] of the motor 75 and the vertical axis is the output torque Trq [Nm].
Trq = Kt × I
This relationship holds. The torque constant Kt corresponds to the slope of the straight line shown in FIG. 7A and represents the output torque characteristic of the motor 75. Further, it is known that the torque constant Kt of the motor 75 is generally equal to the counter electromotive force constant Ke. Therefore,
Kt = Ke (3)

Further, the back electromotive force constant Ke can be calculated from the following equation (4) using the drive voltage V converted from the voltage Vm of the motor 75 and the rotational angular velocity ωm of the motor 75.
Ke = V ÷ ωm (4)
Therefore, the CPU 162 can determine the torque constant Kt of the motor 75 using Expression (5) obtained from Expression (3) and Expression (4).
Kt = Ke = V ÷ ωm (5)

  Here, each unit system is Kt [Nm / A], V [V], and ωm [rad / sec]. In this way, the CPU 162 determines the torque constant Kt based on the measurement result of the voltage Vm corresponding to the drive voltage V of the motor 75 in S703 and the period (corresponding to the rotation speed) of the pulse signal from the encoder sensor 90. To do. In the present embodiment, the output torque characteristic of the motor 75, that is, the torque constant Kt is determined based on the detection result of the rotational speed of the motor 75 and the drive voltage V. Based on the determined torque constant Kt of the motor 75, the drive current I of the motor 75 is controlled so that the pressing force to the sheet bundle S by the upper teeth 97 and the lower teeth 98 is constant.

In S706, the CPU 162 outputs a limit current signal to the current limiting circuit 100 based on the torque constant Kt determined in S705. As shown in FIG. 7A, if the output torque necessary for the stapleless binding process is Tm [Nm], the drive current IL [A] is required to obtain the output torque Tm. The output torque Tm required at the time of the stapleless binding process is a value obtained in advance for each individual stapleless binding device through experiments or the like, and is stored in the ROM 167. This drive current IL is referred to as a limit current value. The CPU 162 determines the limit current value IL using Equation (6) from the torque constant Kt determined in S705.
IL = Tm ÷ Kt (6)
Each unit system is IL [A], Kt [Nm / A], Tm [Nm].
The CPU 162 stores the determined limit current value IL in the RAM 168, and outputs a limit current signal (voltage signal) corresponding to the limit current value IL to the current limiting circuit 100.

  In S707, the CPU 162 determines whether or not the rotational speed Nn of the motor 75 is equal to or less than the predetermined rotational speed X. Here, the rotational speed Nn of the motor 75 will be described. The CPU 162 continuously measures the period of the pulse signal input from the encoder sensor 90 even during the period in which the motor 75 is driven in the forward rotation direction. FIG. 7B is a diagram for explaining how to determine the rotational speed of the motor 75 in the present embodiment, and is a graph in which the horizontal axis represents time [sec] and the vertical axis represents the rotational speed Nn [rps] of the motor 75. It is. In the graph shown in FIG. 7B, the BRAKE signal, which is a motor drive signal, is output from the CPU 162 to the drive circuit 82 after a predetermined time has elapsed from the measurement time T2 of the waveform (e) in FIG. It is a graph similar to the graph until after elapses. The rotation speed Nn indicates the rotation speed of the motor 75 during this period. As shown in FIG. 7B, the CPU 162 measures the cycle of the pulse signal input from the encoder sensor 90 a plurality of times. In the present embodiment, the period of the pulse signal is measured three times continuously, and the result obtained by measuring the three times continuously is always averaged. In FIG. 7B, the timing for measuring the cycle of the pulse signal input from the encoder sensor 90 (cycle Tn measurement timing) is indicated by an arrow. FIG. 7B shows that measurement is performed three times continuously at the first T1. The same applies to the T2 measurement,..., The Tn-2 measurement, the Tn-1 measurement, and the Tn measurement.

Thus, the CPU 162 calculates the average value Tn of the period from the period of the pulse signal measured three times continuously at the Tnth time. Then, the CPU 162 converts the average value Tn of the period of the pulse signal measured three times continuously into the rotational speed Nn of the needleless binding motor 75 using the equation (7).
Nn = (1 ÷ Tn) ÷ 18 (7)
Each unit system is Nn [rps] and Tn [sec]. The numerical value 18 in the equation (7) is the number of slits provided in the disk on the output shaft of the motor 75.

  The CPU 162 constantly calculates the rotational speed Nn of the motor 75 in this way, and the calculated rotational speed Nn is compared with the predetermined rotational speed X, which is the predetermined speed stored in the ROM 167, as needed. Here, the predetermined rotational speed X is a value determined in consideration of the rotational speed characteristics of the motor 75, the environment in which the needleless binding device 52 is installed, the usage time and usage frequency of the device, and the like. Then, for example, X = 5 [rps] (see FIG. 6E). In S707, when the CPU 162 determines that the calculated rotation speed Nn of the motor 75 is equal to or less than the predetermined rotation speed X (less than the predetermined speed), it determines that it is the timing when the stapleless binding process is completed. Here, the timing at which the stapleless binding process is completed means that the sheet bundle is sandwiched between the upper teeth 97 and the lower teeth 98, and a pressing force is applied by the upper teeth 97 and the lower teeth 98 to perform the binding process on the sheet bundle. (See FIG. 6A). The CPU 162 determines that the binding process has been completed when the rotational speed Nn of the motor 75 has become equal to or less than the predetermined rotational speed X, and proceeds to the process of S710. As described above, the CPU 162 completes the binding process when a predetermined time elapses after the driving of the motor 75 is started and the rotation speed of the motor 75 detected by the encoder sensor 90 becomes equal to or lower than the predetermined rotation speed. Judge.

  On the other hand, if the CPU 162 determines in step S707 that the calculated rotation speed Nn of the motor 75 is not less than or equal to the predetermined rotation number X, the process proceeds to step S708. In S708, the CPU 162 determines whether or not a predetermined time has elapsed by referring to a timer (not shown) started in S701. Here, the predetermined time is set to a time exceeding the time required for the binding process. If the CPU 162 determines in S708 that the predetermined time has not elapsed, the process returns to S707. If the CPU 162 determines in S708 that the predetermined time has elapsed, it is highly likely that the motor 75 is not normally driven. Therefore, the CPU 161 notifies the CPU 161 of the image forming apparatus 1 as a timeout error in S709. Stop. Thus, the CPU 162 stops driving the motor 75 when the rotational speed of the motor 75 detected by the encoder sensor 90 is higher than the predetermined rotational speed even after the predetermined time has elapsed.

  In S710, the CPU 162 outputs a motor drive signal to the drive circuit 82, brakes the motor 75 via the drive circuit 82, and stops the forward rotation of the motor. At this time, the upper teeth 97 and the lower teeth 98 are engaged with the sheet bundle S at a predetermined pressure necessary for binding, and the stapleless binding process for the sheet bundle S is performed. The forward rotation of the motor 75 is promptly stopped so that a predetermined pressure is not applied to the sheet bundle S for a time longer than necessary.

  In S711, the CPU 162 outputs a motor drive signal to the drive circuit 82, drives the motor 75 in the reverse rotation (CCW) direction by the drive circuit 82, and moves the cam 92 in the arrow Y direction (clockwise direction) in FIG. Rotate to Thereby, the CPU 162 separates the upper teeth 97 and the lower teeth 98 from the sheet bundle S. In S712, the CPU 162 determines whether or not an ON signal is input from the reference sensor 76. If it is determined that no ON signal is input from the reference sensor 76, the process returns to S712. If the CPU 162 determines that an ON signal is input from the reference sensor 76 in S712, it outputs a motor drive signal to the drive circuit 82 in S713, stops driving the motor 75 via the drive circuit 82, and performs stapleless binding processing. Exit.

  In the present embodiment, the CPU 162 constantly measures the rotational speed Nn of the motor 75, and determines that the timing at which the rotational speed Nn is equal to or lower than the predetermined rotational speed X is the timing at which the binding process is completed. As a result, in the present embodiment, it is possible to detect the timing at which a constant pressing force is applied to the sheet bundle regardless of the number of sheet bundles and the paper type. As described above, according to the present embodiment, it is possible to accurately detect the timing at which a constant pressing force is applied to a sheet bundle regardless of the number of sheet bundles and the type of paper in the binding process.

[Other embodiments]
In the above-described embodiment, the torque constant Kt that is the output torque characteristic of the motor 75 is determined every time the stapleless binding process for the sheet bundle S is performed. However, even if the measurement of the rotation speed, the drive voltage and the drive current, and the determination of the torque constant Kt are performed at any of the following timings, the same effect as that of the above-described embodiment can be obtained. For example, the following configurations can be considered.
A configuration in which the torque constant Kt is determined for each predetermined number of binding processes.
A configuration in which the motor 75 is driven and the torque constant Kt is determined immediately after the power to the sheet processing apparatus 50 or the image forming apparatus 1 is turned on and the sheet processing apparatus 50 has no sheet bundle S.
A configuration in which the torque constant Kt is determined only at the time of binding processing for a predetermined number of copies immediately after power-on, for example, at the time of stapleless binding processing to the first sheet bundle S.
A configuration in which the motor 75 is driven and the torque constant Kt is determined in a state where there is no sheet bundle S during operations other than the stapleless binding process of the image forming apparatus 1 and the sheet processing apparatus 50.

  In the above-described embodiment, the torque constant Kt of the motor 75 is determined based on the rotational speed of the motor 75 and the drive voltage V of the motor 75. However, for example, the driving current I of the motor 75 may be detected by the CPU 162, and the torque constant Kt may be determined based on the rotational speed of the motor 75, the driving voltage V, and the driving current I.

  In the embodiment described above, the sheet processing apparatus 50 installed inside the image forming apparatus 1 has been described as an example. However, the present invention is not limited to the sheet processing apparatus having such a configuration. For example, the configuration of the present embodiment may be applied to the staple-free binding device 52 alone or a sheet processing device that is provided in the image forming apparatus and used independently of the image forming apparatus. Although the sheet processing apparatus has been described as an example, the present invention is not limited to the sheet processing apparatus, and may be applied to an apparatus in which a binding unit is mounted on the image forming apparatus itself. Furthermore, although the needleless binding device has been described as an example, the present invention is not limited to the needleless binding device, and may be applied to other paper binding devices or a mechanism that applies a constant pressure or a constant torque.

  Furthermore, the needleless binding device according to the present embodiment has a configuration in which a tooth mold having a convex portion and a concave portion is pressed against the sheet bundle S using a DC brush motor as a drive source. By providing an operation period in which a load is hardly applied to the motor during a series of binding processing operations, it is possible to detect the torque constant Kt that is the output torque characteristic of the motor every time. As a result, the motor characteristics can be grasped immediately before the binding operation.Therefore, there are not only variations in individual motors, but also fluctuations in the temperature of the surroundings where the device is installed, fluctuations in output torque due to usage time, usage frequency, etc. Also, the pressing force can be controlled to be constant.

  The control according to the present invention for obtaining the torque constant Kt of the motor is also applicable to a half-cut binding method in which, for example, a plurality of sheets P of the sheet bundle S are cut. Furthermore, the present invention can also be applied to a binding method using a normal binding member such as a needle. In other words, any apparatus that uses a motor for the binding process can be applied. Furthermore, the present invention can also be applied to motor control when punching holes such as punch holes in the sheet bundle S.

  As described above, according to the present embodiment, it is possible to accurately detect the timing at which a constant pressing force is applied to a sheet bundle regardless of the number of sheet bundles and the type of paper in the binding process.

52 Needleless binding device 75 Needleless binding motor 90 Encoder sensor 162 CPU

Claims (13)

A binding means for performing a binding process by pressing the sheet bundle;
A motor for driving the binding means to press the sheet bundle;
Speed detecting means for detecting the speed of the motor;
Control means for applying a brake to the motor when the speed detected by the speed detecting means falls below a predetermined speed during a period in which the binding means is pressing the sheet bundle;
A sheet processing apparatus comprising:   When the speed detected by the speed detection means does not become less than the predetermined speed even after the time required for the binding process has elapsed while the binding means is pressing the sheet bundle, The sheet processing apparatus according to claim 1, wherein the driving of the sheet is stopped.   The control means is configured such that the speed detected by the speed detection means is equal to or lower than a second predetermined speed higher than the predetermined speed while the motor is being driven and the binding means is not pressing the sheet bundle. The sheet processing apparatus according to claim 1, wherein driving of the motor is stopped.   4. The sheet processing apparatus according to claim 1, wherein after the brake is applied to the motor, the control unit drives the motor so that the motor rotates in the reverse direction. 5. Furthermore, it has a voltage detection means for detecting the drive voltage of the motor,
The control unit determines a current value of a driving current of the motor when the binding unit presses the sheet bundle based on a detection result of the speed detection unit and a detection result of the voltage detection unit, and determines The sheet processing apparatus according to claim 1, wherein the driving of the motor is controlled based on the current value.   The control means determines a torque constant of the motor based on the detection result of the speed detection means and the detection result of the voltage detection means, and based on the determined torque constant, the current of the drive current of the motor The sheet processing apparatus according to claim 5, wherein a value is determined.   The said control means determines the said torque constant using the detection result by the said speed detection means when the said motor is unloaded, and the detection result by the said voltage detection means. Sheet processing equipment.   The sheet processing apparatus according to claim 5, wherein the control unit determines the current value every time the binding process is performed.   The sheet processing apparatus according to claim 5, wherein the control unit determines the current value when the sheet processing apparatus is powered on.   The said control means determines the said electric current value when performing the said binding process with respect to the sheet bundle of the predetermined number of sheets among several sheet bundles, The said any one of Claims 5 thru | or 7 characterized by the above-mentioned. Sheet processing equipment.   The binding means includes a first pressing portion that presses one surface of the sheet bundle, and a second pressing portion that is provided to face the first pressing portion and presses the other surface of the sheet bundle. 11. The binding process according to claim 1, wherein the binding process is performed by pressing the sheet bundle with the first pressing portion and the second pressing portion. The sheet processing apparatus according to the description.   The sheet processing apparatus according to claim 6, wherein the binding unit binds the sheet bundle by intertwining fibers of the sheets of the sheet bundle. Image forming means for forming an image on a sheet;
A stacking unit on which sheets imaged by the image forming unit are stacked;
A sheet processing apparatus according to any one of claims 1 to 12,
And the sheet processing apparatus performs a binding process by pressing a sheet bundle composed of a plurality of sheets stacked on the stacking unit.

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