JP2012176808A - Post-processing apparatus, image forming system, and method for detecting abnormal stapling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine abnormal stapling.SOLUTION: A post-processing controller 70 determines abnormal stapling on the basis of a null stapling signal in a determination period ΔT, from firstly detecting an L level as the null stapling signal until starting clinching operation, after starting stapling operation. For example, once the L level is detected as the null stapling signal in the determination period ΔT, the post-processing controller 70 determines it as a situation that there is no abnormal stapling.

Description

  The present invention relates to a post-processing apparatus, an image forming system, and a staple abnormality detection method.

  2. Description of the Related Art Conventionally, a post-processing device that creates a booklet by performing edge binding and saddle stitching on a sheet discharged from an image forming apparatus is known. Such a binding process includes a stapling operation in which the staple unit (stapler) drives the staple needle into a predetermined position of the paper, and a clinch operation in which the needle receiving unit (clincher) pushes and bends the needle tip of the staple needle that has been driven into the paper by the stapler. And realized.

  For example, Patent Document 1 discloses a post-processing device that can detect a staple abnormality, that is, a staple operation abnormality such as staple blanking, staple staple breakage, or staple needle buckling. Specifically, according to this post-processing apparatus, when the stapling operation is normally performed, the stapler and the portion that receives the staple needle in the clincher and bends it (the bent portion) are connected by the staple needle and are electrically connected. To do. As a result, the output of the detection signal to the control unit 70 becomes L. Conversely, if the output of the detection signal is H, it is determined that a staple abnormality has occurred.

  For example, Patent Document 2 discloses a technique for detecting a staple abnormality with a simple configuration. In this method, the potential of the clinch bar varies depending on the presence or absence of the staple needle, and the potential of the clinch bar varies depending on whether the staple needle is properly stapled. Cutting and buckling of the staple needle can be detected.

Japanese Patent Laid-Open No. 8-198506 Japanese Patent Laid-Open No. 9-255221

  However, in order to accurately determine whether or not an abnormality has occurred in the stapling operation, it is necessary to determine this based on the conduction state in an appropriate determination period. With conventional methods, it is possible to accurately determine a staple abnormality. May not be possible.

  The present invention has been made in view of such circumstances, and an object thereof is to accurately determine a staple abnormality.

  In order to solve such a problem, the first invention is arranged such that a stapling portion that performs a stapling operation for driving a staple needle into a predetermined position of a sheet and a striking portion that is opposed to the striking portion with the sheet interposed therebetween. Receives the staple tip of the staple needle that has been driven into the paper, and conducts contact between the staple receiving portion that holds the staple needle on the paper by a clinching operation that pushes and bends the received needle tip, and the staple needle that is driven by the striker portion and the needle receiving portion. Provided is a post-processing apparatus having a detection unit that detects a state and a determination unit that determines a staple abnormality. In this case, the determination unit determines the staple abnormality based on the detection state of the detection unit in the determination period from when the detection unit first detects the conduction state after the start of the stapling operation to when the clinch operation starts.

  Here, in the first invention, it is preferable that the determination unit determines that there is no staple abnormality when the detection unit detects the conduction state once in the determination period.

  In the first invention, it is preferable that the determination unit determines that there is no staple abnormality when the detection unit detects a conduction state more than a specified number of times during the determination period.

  In the first invention, the needle receiving portion receives the needle tip of the staple needle driven by the needle hitting portion, and temporarily sets the needle tip of the staple needle according to the angle formed with the approach direction of the needle tip. It is preferable to include a clincher plate that bends to a position and a drive unit that performs a clinching operation by rotating the clincher plate to bend the needle tip of the staple needle along the paper.

  In the first aspect of the invention, the determination unit may perform the clinching on the condition that when the clincher plate is returned to the initial position upon completion of the clinching operation, the detection unit is switched from the conductive state to the non-conductive state. It is preferable to determine that the operation has been performed normally.

  According to a second aspect of the present invention, there is provided an image forming system including an image forming apparatus that forms an image on a sheet, and a post-processing apparatus that performs post-processing on the sheet discharged from the image forming apparatus. In this case, the post-processing device is disposed so as to face the staple unit with a staple unit for performing a staple operation for implanting a staple needle at a predetermined position of the sheet, and the staple unit that is disposed on the sheet by the staple unit. A staple receiving portion that holds the staple needle on the paper by a clinching operation that pushes and bends the received needle tip, and a detection portion that detects contact between the staple needle and the staple receiving portion that the strike needle portion strikes as a conductive state And a determination unit for determining stapling abnormality. Here, the determination unit determines a staple abnormality based on a detection state of the detection unit in a determination period from when the detection unit first detects the conduction state after the start of the stapling operation to when the clinch operation starts.

  According to a third aspect of the present invention, there is provided a first step in which the hitting portion performs a stapling operation in which the staple needle is driven into a predetermined position of the paper, and a needle receiving portion disposed so as to face the hitting portion with the paper interposed therebetween. A second step of receiving the staple tip of the staple needle that has been driven into the sheet, and clamping the staple needle to the paper by a clinching operation that pushes and bends the received needle tip, and the contact between the staple needle that is driven into the staple unit and the needle receiving unit. A staple abnormality detection method comprising: a third step of determining a staple abnormality based on a detection state detected as a conduction state. In this case, the third step is a fourth step for determining whether or not a conduction state is first detected after the start of the stapling operation, and a clinch operation is started after the conduction detection is determined in the fourth step. And a fifth step of determining stapling abnormality based on the detection state in the determination period until.

  According to the present invention, it is possible to set the substantial period of the staple operation as the determination period by determining the staple abnormality based on the detection state of the detection unit in the determination period. As a result, the range (period and execution time thereof) for monitoring the detection state of the detection unit can be optimized, so that the staple abnormality can be accurately determined.

1 is an explanatory diagram schematically showing the overall configuration of an image forming system to which a paper discharge tray device 40 according to the first embodiment is applied. Explanatory drawing which shows typically the outline of operation | movement of the paper conveyance path | route in each post-processing apparatus 20, and each part 20-60. Configuration diagram schematically showing configuration of saddle stitching section 50 Explanatory diagram schematically showing the operation of the clincher 53 Explanatory drawing which shows the detail of a staple operation and a clincher operation typically Explanatory drawing which shows typically the detection structure of the post-processing control part 70. The flowchart which shows the judgment processing by the post-processing control part 70 concerning 1st Embodiment. Explanatory drawing which shows transition of various signals concerning saddle stitching processing The flowchart which shows the judgment process by the post-processing control part 70 concerning 2nd Embodiment.

(First embodiment)
FIG. 1 is an explanatory diagram schematically showing the overall configuration of an image forming system to which a paper discharge tray device 40 according to the first embodiment of the present invention is applied. The image forming system according to the first embodiment includes an image forming apparatus 10 and a post-processing apparatus 20.

  The image forming apparatus 10 is an electrophotographic image forming apparatus such as a copying machine, and forms an image on a sheet P based on image data. The image forming apparatus 10 includes a document reading device 5, a photoconductor 11, a charging unit 12, an image exposing unit 13, a developing unit 14, a transfer unit 15A, a separating unit 15B, a cleaning device 16, and a fixing device. 18 and an image formation control unit 19.

  The document reading device 5 is provided on the upper portion of the image forming apparatus 10 and includes an automatic document feeder that automatically moves the document when reading an image. The document reading device 5 reads an image formed on a document and outputs a predetermined image signal. The output image signal is created as image data by performing A / D conversion.

  An image reading control unit (not shown) included in the document reading device 5 performs processing such as shading correction, dither processing, and compression on image data, and image formation control is performed using the data obtained by this processing as final image data. Stored in the RAM of the unit 19. Note that the image data may be received from a personal computer connected to the image forming apparatus 1 or another image forming apparatus as well as data output from the document reading apparatus 5.

  The surface of the photoreceptor 11 is uniformly charged by the charging unit 12. The image exposure unit 13 scans and exposes the surface of the photoconductor 11 with a laser beam in accordance with output information output from the image formation control unit 19 based on the image data. Thereby, a latent image is formed on the surface of the uniformly charged photoreceptor 11. The developing unit 14 reversely develops the latent image with toner, whereby a toner image is formed on the surface of the photoreceptor 11.

  The paper P stored in the paper storage unit 17A is fed to the transfer unit 15A. The transfer unit 15A transfers the toner image on the surface of the photoconductor 11 to the paper P, and then the separation unit 15B separates the paper P on which the toner image is transferred from the photoconductor 11. The intermediate transport unit 17B transports the separated paper P to the fixing device 18. The fixing device 18 performs a fixing process by heating and pressing the paper P. The paper discharge unit 17C discharges the paper P on which the fixing process has been performed to the post-processing device 20. On the other hand, the cleaning device 16 removes the toner remaining on the surface of the photoconductor 11 after the toner image is transferred onto the paper P by the transfer unit 15A.

  When image formation is performed on both sides of the sheet P, the sheet P on which the fixing process has been performed by the fixing device 18 is moved to the reverse conveyance unit 17E side in which the conveyance direction is different from the paper discharge unit 17C side by the conveyance path switching plate 17D. And can be switched. The reversing conveyance unit 17E switches the paper P to reverse the front and back of the paper P, and then conveys the paper P to the transfer unit 15A. The transfer unit 15A transfers the toner image to the back surface of the paper P, and the paper P passes through the fixing device 18 and is discharged from the paper discharge unit 17C to the post-processing device 20.

  The image formation control unit 19 has a function of controlling the image forming apparatus 10 in an integrated manner. As the image formation control unit 19, for example, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface. Can be used. The image formation control unit 19 performs various calculations according to the control program stored in the ROM, and controls the operation state of the image forming apparatus 1 based on the calculation results.

The image forming control unit 19 controls each unit of the image forming apparatus 1 to execute the following series of processes to form a toner image on the paper P.
(1) Charge the photosensitive member 11 (2) Form an electrostatic latent image on the photosensitive member 11 by the image exposure unit 13 (3) Adhere toner to the electrostatic latent image formed by the developing unit 14 (4 (1) The toner image on the photoconductor 11 is transferred to the paper P by the transfer unit 15A. (6) The toner image transferred to the paper P by the fixing device 18 is fixed.

  The post-processing device 20 performs various post-processing on the paper P discharged from the image forming apparatus 10. Examples of post-processing performed by the post-processing device 20 include half-folding processing and saddle stitching processing. Here, the half-folding process is a process for performing the middle folding on the sheet bundle, and the saddle stitching process is a process for performing the middle folding and the saddle stitching on the sheet bundle. However, the post-processing device 20 can also discharge the paper P without performing any processing on the paper P discharged from the image forming apparatus 10.

  In the present embodiment, the post-processing device 20 is mainly configured by a center folding unit 30, a saddle stitching unit 50, a sheet cutting unit 60, and a post-processing control unit 70. Hereinafter, the configuration and operation of the post-processing device 20 will be described assuming that the saddle stitching process is set to be executed. Here, FIG. 2 is an explanatory view schematically showing an outline of the operation of the paper transport path and the units 20 to 60 in the post-processing apparatus 20.

  When the paper P discharged from the image forming apparatus 10 is introduced into the inlet portion 21 of the post-processing device 20, it is transported by the inlet roller 22 and transported to the paper transport path r 1 by the transport path switching member 23. The paper P transported to the paper transport path r1 descends substantially vertically and is temporarily stopped at a predetermined position (first stop position) Q1. Subsequent sheets P sequentially arrive at the first stop position Q1, whereby a plurality of sheets P are accommodated in a stacked state.

  The accommodated paper P is sent out to the paper transport path r2 by the transport roller pair 24A, 24B, and then transported by the first transport roller pair 24C, 24D. When the paper P reaches a predetermined position (second stop position) Q2, the first transport roller pair 24C, 24D temporarily stops the transport of the paper P. Here, in the paper transport path r2, the paper P is transported with the paper surface upright, and is guided by a guide plate (not shown) provided between the transport roller pair 24B and the first transport roller pair 24C. By being deflected substantially at a right angle, it is conveyed in such a manner as to wrap around from the side surface inside the post-processing device 20 to the front surface Bf.

  Next, the paper P is transported vertically upward by the second transport roller pair 24E, then deflected in the horizontal direction, and then moved along the paper transport path r3. The alignment member (not shown) is arranged on the downstream side in the paper conveyance direction in the paper conveyance path r3, and aligns the ends of the papers P by positioning the papers P by bringing the leading edges of the papers into contact with each other. At the same time, the paper P is temporarily stopped at a predetermined position (third stop position) Q3.

  In addition, a half-folding portion 30 is disposed in the paper transport path r3. The middle folding unit 30 includes a pair of folding rollers that are pressed against each other, a folding plate, and the like, and performs a middle folding process in which the paper P is folded in half at the center of the paper P. Specifically, by raising the folding plate, the folding roller is passed while pushing the center of the sheet between the pair of folding rollers, and then the folding roller is reversed. Thereby, the paper P can be bent at the center thereof. A sheet (hereinafter referred to as “signature PA”) on which a crease is formed by the middle folding unit 30 is a sheet conveyance path that extends in the extending direction of the fold b by the conveyance belt 41, the conveyance claw 42, and the introduction guide member 43. r4 is conveyed and sent to the saddle stitching section 50.

  FIG. 3 is a configuration diagram schematically showing the configuration of the saddle stitching portion 50, in which the direction perpendicular to the paper surface corresponds to the transport direction of the paper transport path r4. The signature PA that has been subjected to the middle folding process in the middle folding section 30 travels on the paper conveyance path r4 and is placed on the hook stacking member 51 of the saddle stitching section 50 (see FIG. 3). The subsequent signatures PA that have undergone the middle folding process continue to be sequentially stacked on the stacking member 51 through the sheet transport path r4.

  The hook stacking member 51 includes two guide plates that are substantially orthogonal to each other, and is fixed to the apparatus main body. In the vicinity of the top of the hook stacking member 51, a pressing member 52 that is spring-biased and can be moved up and down is arranged in a state of being supported by a clincher (needle receiving portion) 53. The top of the pressing member 52 has a convex shape that is substantially perpendicular to the upper side, and the crease b of the signature PA is placed on the top ridge line. The signature PA placed on the hook stacking member 51 and the pressing member 52 is aligned in the crease direction by a width matching means (not shown).

  Above the pressing member 52, a stapler (needle hitting portion) 54 is fixedly disposed. Inside the hook stacking member 51, a pressing member 52 and a clincher 53 are supported so as to be movable in the vertical direction. Two sets of the saddle stitching mechanism composed of the stapler 54 and the clincher 53 are arranged at a predetermined distance in the extending direction of the fold line b. That is, the booklet PS with the staples SP applied at two places is formed along the fold b of the signature bundle on the pressing member 52 by the two sets of saddle stitching mechanisms.

  Specifically, after a predetermined number of signatures PA are stacked on the hook stacking member 51 and subjected to alignment processing, the pressing members 52 disposed on both sides of the clincher 53 are lifted by a driving means (not shown) such as a cam mechanism. Is done. As shown in FIG. 4A, at the upper limit position of the pressing member 52, the uppermost signature PA is held in a state of being pressed and pressed against a paper receiving surface (not shown) of the stapler 54.

  As shown in FIG. 4B, when the driving means continues to drive, the clincher 53 rises, pinches the signature PA loaded on the pressing member 52, and presses against the needle striking surface of the stapler 54. Let In this state, the stapler 54 operates to perform a stapling operation to drive the staple needle SP, and the clincher 53 further operates to perform a clinching operation described later, whereby the signature PA is saddle stitched.

  FIG. 5 is an explanatory diagram schematically showing details of the stapling operation and the clincher operation. When the clincher 53 is pressed against the staple surface of the stapler 54 via the signature PA (see FIG. 5A), the stapling operation is started. Specifically, the operation (rotation) of the staple motor, which is a driving unit for driving the staple needle SP, built in the stapler 54 is started. As a result, the staple needle SP is driven out from the stapler 54.

  As shown in FIG. 5B, the staple needle SP driven out from the stapler 54 passes through the signature PA and reaches the clincher plate 53d of the clincher 53. The clincher plate 53d is configured to be rotatable in accordance with the operation of a solenoid 53a described later, and has a needle receiving surface that receives the staple tip of the staple needle SP driven by the stapler 54. Initially, the needle receiving surface is arranged so as to form a predetermined angle with the staple tip of the staple needle SP driven by the stapler 54. As a result, the clincher plate 53d receives the staple tip of the staple needle SP driven by the stapler 54 and temporarily bends the staple tip of the staple needle SP according to the angle formed by the entry direction of the staple tip.

  Next, when a predetermined time elapses from the stapling operation, the clinch operation is started. Specifically, when the solenoid 53a starts operating, the plunger 53b is raised, and the power transmission plate 53c connected thereto is also raised. The power transmission plate 53c is located below the clincher plate 53d, and rotates the clincher plate 53d so as to press the staple tip of the staple needle against the signature SP side as it rises. As a result, as shown in FIG. 5C, the clincher plate 53d receives the power from the power transmission plate 53c and bends the needle tip of the staple needle SP along the signature SP. When this series of clinching operations is completed, the operation of the solenoid 53a is stopped, the biasing force of the spring 53e is received, the plunger 53b and the power transmission plate 53c are returned to the initial position, and the clincher plate 53d is also returned to the initial position. Return.

  After such a saddle stitching process, the clincher 53 and the pressing member 52 are returned to the state before the saddle stitching process start shown in FIG. 3, and the booklet PS produced by the saddle stitching process is placed on the saddle stacking member 51. Placed.

  Referring again to FIGS. 1 and 2, the booklet PS is conveyed to the paper cutting unit 60 by an arm member and booklet conveying means 80 (not shown). In the booklet PS, the edge which is the free end on the opposite side of the fold line b is uneven. The sheet cutting unit 60 cuts and aligns the edge of the sheet bundle PS (cutting process). The booklet PSS produced by cutting the fore edge is discharged to a discharge tray (not shown) disposed outside the front side Bf of the post-processing device 20.

  The post-processing control unit 70 has a function of controlling the post-processing device 20 in an integrated manner. As the post-processing control unit 70, for example, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface. Can be used. The post-processing control unit 70 performs various calculations according to the control program stored in the ROM, and controls the operation state of the image forming apparatus 1 based on the calculation results. In other words, the post-processing control unit 70 controls each part of the post-processing device 20 to perform a half-folding process or a saddle stitching process, or perform a cutting process as necessary.

  Further, in relation to the present embodiment, the post-processing control unit 70 determines a staple abnormality, that is, a staple operation abnormality such as stapling of the staple needle, staple breakage, or staple buckling when the saddle stitching process is executed. Or clinching abnormality, that is, whether or not the clinching operation is normally completed.

  FIG. 6 is an explanatory diagram schematically illustrating a detection configuration of the post-processing control unit 70. The CPU that executes various determination processes as the post-processing control unit 70 is electrically connected to the stapler 54, and the mechanical contact between the staple needle SP driven by the stapler 54 and the clincher 53 is brought into an electrically conductive state. Detect (detection unit). Specifically, the stapler 54 is in an electrically insulated state (floating), while the clincher 53 is connected to the ground (reference potential). The stapler 54 is connected to the CPU via a resistor R2 mounted on the control board 71, and a connection point between the stapler 54 and the resistor R2 is connected to a power supply voltage (DC5V) via the resistor R1, A connection point between the resistor R2 and the input side of the CPU is connected to the ground via a capacitor C.

  When the stapling operation is not performed, since the stapler 54 and the clincher 53 are electrically separated, the stapler 54 maintains an insulated state. In this case, a high level signal (hereinafter referred to as “H level”) indicating a non-conduction state is input to the CPU. On the other hand, when the stapling operation is started, the stapler 54 strikes the staple needle SP so that the staple needle SP contacts the clincher plate 53d. As a result, the stapler 54 and the clincher 53 are electrically connected via the staple needle SP, and the current from the power supply voltage flows to the ground via the stapler 54, the staple needle SP, and the clincher 53. Therefore, strictly speaking, during the staple operation, during the period in which the staple needle SP driven by the stapler 54 and the clincher 53 are in mechanical contact, the CPU has a low level (hereinafter referred to as “L level”) indicating a conduction state. ) Signal is input.

  The post-processing control unit 70 determines stapling abnormality in accordance with a detection state of conduction or non-conduction, that is, an L level or H level signal (hereinafter referred to as “empty driving signal”) (determination unit). Hereinafter, detailed determination processing by the post-processing control unit 70 will be described with reference to FIG. Here, FIG. 7 is a flowchart showing a determination process by the post-processing control unit 70.

  First, in step 10 (S10), the post-processing control unit 70 sets the print mode set by the user in the post-processing device 20 through an operation unit (not shown). For example, the operation unit includes buttons, switches, and the like, and is operated by the user to perform various printing modes (printing conditions (number of copies, presence / absence of double-sided printing, magnification, etc.), post-processing conditions (half-folding processing, saddle stitching). Processing, cutting processing, etc.)) is input to the image formation control unit 19. The image formation control unit 19 instructs the post-processing control unit 70 on the print mode input from the operation unit. As a result, the print mode set by the user is set for the image forming apparatus 10 and the post-processing apparatus 20.

  In step 11 (S11), the post-processing control unit 70 starts the printing operation together with the operation start of the image formation control unit 19.

  In step 12 (S12), the post-processing control unit 70 determines whether or not stapling is present, that is, whether or not saddle stitching processing is set as the print mode. If an affirmative determination is made in step 12, that is, if there is a staple, the process proceeds to step 13 (S13). On the other hand, if a negative determination is made in step 12, that is, if there is no staple, the process proceeds to step 22 (S22) described later.

  In step 13, the post-processing control unit 70 starts the stapling operation on the condition that a predetermined number of sheets P are stacked on the hook stacking member 51 and the requirement for executing stapling is satisfied. Specifically, the post-processing control unit 70 starts the operation (rotation) of the staple motor built in the stapler 54.

  In step 14 (S14), the post-processing control unit 70 determines whether or not the idle driving signal has been switched from the H level to the L level. This step 14 has a function of determining whether or not the blank shot signal first becomes L level after the start of the stapling operation. If a negative determination is made in step 14, that is, if the idling signal remains at the H level, the process proceeds to step 15 (S15). On the other hand, if an affirmative determination is made in step 14, that is, if the first L level as an empty shot signal is determined, the process proceeds to step 16 (S16).

  In step 15, the post-processing control unit 70 determines whether or not the start timing of the clinching operation has been reached. The start timing of the clinching operation is set in advance after a lapse of a predetermined time starting from the start timing of the stapling operation. If an affirmative determination is made in step 15, that is, if the start timing of the clinching operation has been reached, the process proceeds to step 27 (S27) described later. On the other hand, if a negative determination is made in step 15, that is, if the start timing of the clinching operation has not been reached, the process returns to step 14 again.

  In step 16, the post-processing control unit 70 samples the signal level (L level, H level) of the idle signal for a predetermined determination period ΔT. The determination period ΔT in step 16 corresponds to the period from the timing when the determination is affirmative in step 14, that is, the timing when the idle signal becomes the L level for the first time to the start timing of the clinch operation.

  In step 17 (S17), the post-processing control unit 70 determines whether or not the idle signal sampled in the determination period ΔT has an L level. If an affirmative determination is made in step 17, that is, if even one sampled blank signal has an L level, the process proceeds to step 18 (S18). If a negative determination is made in step 17, that is, if the sampled idle signal does not have an L level, the process proceeds to step 26 described later.

  In step 18, the post-processing control unit 70 starts a clinching operation. Specifically, the operation of the solenoid 53a is started. In step 19 (S19), when the post-processing control unit 70 operates the solenoid 53a for a predetermined time set in advance, the post-processing control unit 70 stops the operation of the solenoid 53a and ends the clinch operation. Thereby, the plunger 53b returns to the initial position by the biasing force of the spring 53e, and similarly, the clincher plate 53d also returns to the initial position.

  In step 20 (S20), the post-processing control unit 70 determines whether or not the idle driving signal has been switched from the L level to the H level. If an affirmative determination is made in step 20, that is, if the idle driving signal is switched to the H level, the process proceeds to step 21 (S21). On the other hand, if a negative determination is made in step 20, that is, if the idle signal remains at the L level, the process proceeds to step 23 (S23) described later.

  In step 21, the post-processing control unit 70 receives an affirmative determination in step 20, and determines that the clinching operation has been normally completed. In step 22, the post-processing control unit 70 determines that the printing operation has been normally completed, and ends this routine. In a case where a plurality of booklets are created, it is possible to return to the process of step 13 and repeat the subsequent processes without determining that the printing operation has been normally completed in step 22.

  On the other hand, in step 23, the post-processing control unit 70 receives a negative determination in step 20, and determines that the clinching abnormality, that is, the clinching operation has not been completed normally. In this case, the post-processing control unit 70 instructs to stop printing in step 24 (S24), and displays an error message indicating a clinch abnormality on a display unit (not shown) in step 25 (S25).

  On the other hand, in step 26, the post-processing control unit 70 receives an affirmative determination in step 15 or a negative determination in step 17, and determines that there is a staple abnormality, that is, the staple operation has moved. In this case, the post-processing control unit 70 instructs to stop printing in step 27 (S27), and displays an error message indicating stapling abnormality on a display unit (not shown) in step 28 (S28).

  FIG. 8 is an explanatory diagram showing transition of various signals related to the saddle stitching process. In this figure, (a) shows the operation (rotation) and stop state of the staple motor, (b) shows the state of the idle driving signal (H level or L level), and (c) shows the clincher 53. The operation and stop state of the solenoid 53a are shown.

  As can be seen from the operations shown in the flowcharts described above, according to the present embodiment, after the stapling operation is started (timing t0), the post-processing control unit 70 outputs L as an empty shot signal (detection state of the detection unit). The staple abnormality is determined based on the blank driving signal in the determination period ΔT from when the level is first detected until the clinch operation is started (timing t1).

  According to such a configuration, it is possible to set the substantial period of the stapling operation as the determination period ΔT by determining the staple abnormality based on the blank driving signal in the determination period ΔT. As a result, the range (period and execution timing) for monitoring the idle driving signal can be optimized, so that the staple abnormality can be accurately determined.

  Further, according to the present embodiment, the post-processing control unit 70 determines that there is no stapling abnormality when the L level is detected even once as a blank shot signal in the determination period ΔT. According to such a configuration, it is possible to determine that there is no staple abnormality by detecting the L level at least once by optimizing the determination period ΔT.

  Further, in the present embodiment, the clincher 53 receives the needle tip of the staple needle SP driven by the stapler 54 and temporarily sets the needle tip of the staple needle SP according to the angle formed with the approach direction of the needle tip. The clincher plate 53d to be bent and the solenoid 53a that performs a clinching operation by rotating the clincher plate 53d to bend the needle tip of the staple needle SP along the signature SP. According to such a configuration, unnecessary noise or the like is likely to be generated in the blank shot signal because the contact between the staple needle SP driven by the stapler 54 and the clincher plate 53d of the clincher 53 is detected as a conductive state. However, according to the present embodiment, it is possible to eliminate erroneous determination factors such as noise by optimizing the determination period ΔT. Thereby, it is possible to accurately determine the staple abnormality.

  Further, in the present embodiment, the post-processing control unit 70 is provided on the condition that the idle driving signal is switched from the L level to the H level when the clincher plate 53d is returned to the initial position at the end of the clinching operation. Then, it is determined that the clinching operation has been normally performed. According to this configuration, it is possible to determine that the clinching operation has been normally performed through the above-described blank shot signal. This makes it possible to determine effectively whether the saddle stitching process has been performed reliably.

(Second Embodiment)
FIG. 9 is a flowchart illustrating a staple abnormality determination process according to the second embodiment. The staple abnormality determination process according to the second embodiment is different from that of the first embodiment in the staple abnormality determination method based on the idle driving signal in the determination period ΔT. Note that the description of the same configuration and operation as those in the first embodiment will be omitted, and the following description will focus on the differences.

  In step 40 (S40) to step 45 (S45), the post-processing control unit 70 sets the print mode, starts the printing operation, and determines whether there is stapling, as in steps 10 to 15 described in the first embodiment. Whether the start timing of the stapling operation or the start timing of the clinch operation has been reached.

  If it is determined in step 44 (S44) that the blanking signal after the start of the stapling operation first becomes L level, the post-processing control unit 70 checks the blanking signal in step 46 (S46). In step 47 (S47), when the post-processing control unit 70 confirms the L level as the blank signal in the above-described confirmation processing, the post-processing control unit 70 increments the count value of the counter and reflects the result in the counter.

  In step 48 (S48), the post-processing control unit 70 determines whether or not the determination period ΔT, that is, the period from the timing when the idle signal first becomes the L level to the start timing of the clinch operation has elapsed. . If an affirmative determination is made in step 48, that is, if the determination period ΔT has elapsed, the process proceeds to step 49 (S49). On the other hand, if a negative determination is made in step 48, that is, if the determination period ΔT has not elapsed, the process returns to step 46.

  In step 49, the post-processing control unit 70 refers to the counter. In step 50 (S50), the post-processing control unit 70 determines whether or not the number of times of the L level is equal to or greater than a specified value (N times) in the determination period ΔT. If an affirmative determination is made in step 50, that is, if the number of times of the L level is equal to or greater than the specified value (N times), the process proceeds to step 51 (S51). On the other hand, if a negative determination is made in step 50, that is, if the number of times of the L level is not equal to or greater than the specified value (N times), the process proceeds to step 59 (S59).

  In step 51 to step 61 (S61), the post-processing control unit 70 performs each process in the same manner as in step 18 to step 28 shown in the first embodiment.

  As described above, in the present embodiment, the post-processing control unit 70 determines that there is no stapling abnormality when the L level is detected as a blank signal in the determination period ΔT.

  According to this configuration, the post-processing control unit 70 determines that there is no stapling abnormality when an L level blanking signal is detected above a specified value in the determination period ΔT. According to such a configuration, since it is determined that there is no staple abnormality when the L level is detected a plurality of times, even if the effect of noise or the like is included in the blank shot signal, the staple abnormality is erroneously determined. The possibility that it will end up can be reduced. As a result, it is possible to perform a staple abnormality determination with high reliability.

  The image forming system according to the embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications are possible within the scope of the invention. . In addition to the image forming system, the post-processing apparatus and the staple abnormality detection method itself function as part of the present invention. Furthermore, although the above-described embodiment has been described on the assumption that the saddle stitching process is performed, the present invention can be applied to all methods for performing a binding process using a staple, such as an end binding process.

DESCRIPTION OF SYMBOLS 5 Document reader 10 Image forming apparatus 11 Photoconductor 12 Charging part 13 Image exposure part 14 Developing part 15A Transfer part 15B Separation part 16 Cleaning device 18 Fixing apparatus 19 Image formation control part 20 Post-processing apparatus 30 Middle folding part 50 Saddle binding part 51 Clamping member 52 Pressing member 53 Clincher 53a Solenoid 53b Plunger 53c Power transmission plate 53d Clincher plate 53e Spring 54 Stapler 60 Paper cutting unit 70 Post-processing control unit

Claims (7)

A staple unit for performing a staple operation for driving the staple needle into a predetermined position on the paper;
The staple is placed opposite to the needle hitting part across the paper, and the staple needle is received on the paper by the clinch operation that receives and staples the staple needle driven into the paper by the needle hitting part. A needle receiving part to be fastened;
A detection unit that detects contact between the staple needle driven by the needle unit and the needle receiving unit as a conductive state;
A determination unit for determining stapling abnormality;
The determination unit determines a staple abnormality based on a detection state of the detection unit in a determination period from when the detection unit first detects a conduction state after starting the stapling operation to when the clinch operation starts. And a post-processing device.   The post-processing apparatus according to claim 1, wherein the determination unit determines that there is no staple abnormality when the detection unit detects a conduction state once in the determination period.   The post-processing apparatus according to claim 1, wherein the determination unit determines that there is no staple abnormality when the detection unit detects a continuity state more than a specified number of times during the determination period. The needle receiving portion is
A clincher plate that temporarily bends the staple tip of the staple needle according to the angle formed with the approach direction of the staple tip while receiving the staple tip of the staple needle driven by the staple portion;
A drive unit for performing the clinching operation by rotating the clincher plate to bend the needle tip of the staple needle along the paper;
The post-processing apparatus according to claim 1, comprising:   When the clincher plate is returned to the initial position upon completion of the clinching operation, the determination unit performs the normal operation of the clinching operation on condition that the detection unit is switched from a conductive state to a non-conductive state. The post-processing apparatus according to claim 4, wherein the post-processing apparatus determines whether the process is performed. In an image forming system,
An image forming apparatus for forming an image on paper;
A post-processing device that performs post-processing for the paper discharged from the image forming apparatus,
The post-processing device includes:
A staple unit for performing a staple operation for driving the staple needle into a predetermined position on the paper;
The staple is disposed opposite to the needle hitting part with the paper sandwiched therebetween, and receives the staple tip of the staple needle driven into the paper by the needle hitting part, and the staple needle is applied to the paper by a clinch operation for pushing and bending the received needle tip. A needle receiving part to be fastened;
A detection unit that detects contact between the staple needle driven by the needle unit and the needle receiving unit as a conductive state;
A determination unit for determining stapling abnormality;
The determination unit determines a staple abnormality based on a detection state of the detection unit in a determination period from when the detection unit first detects a conduction state after starting the stapling operation to when the clinch operation starts. An image forming system. In the staple abnormality detection method,
A first step of performing a stapling operation in which the staple unit drives a staple needle into a predetermined position of the paper;
A staple receiving portion arranged opposite to the staple hitting portion across the paper receives the staple tip of the staple needle driven into the paper and holds the staple needle on the paper by a clinch operation that pushes and bends the received needle tip. A second step;
A third step of determining a staple abnormality based on a detection state in which contact between the staple needle to be driven by the needle placement unit and the needle receiving unit is detected as a conduction state;
The third step includes
A fourth step of determining whether or not a conduction state is first detected after starting the stapling operation;
A fifth step of determining a staple abnormality based on the detection state in a determination period from the determination of continuity detection in the fourth step to the start of the clinching operation;
A method for detecting a staple abnormality, comprising:

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