Post-processing device and image forming system
The post-processing device eliminates sensors by using stopper members and driving time/encoder feedback for precise positioning, reducing costs and wear, addressing the need for sensor-based positioning in existing devices.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- RICOH CO LTD
- Filing Date
- 2022-02-25
- Publication Date
- 2026-05-19
AI Technical Summary
Existing post-processing devices require sensors for positioning reciprocating driven members, leading to increased costs due to the need for installation space and harness routing.
A post-processing device that eliminates the need for sensors by using stopper members at both ends of the driven member's movement range, defining the movement range, and determining the reference position based on driving time or encoder feedback to position the driven member accurately.
Achieves cost reduction by eliminating the need for sensors, while ensuring precise positioning of the driven member without additional hardware, thus reducing unnecessary load and component wear.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a post-processing device and an image forming system.
Background Art
[0002] In an image forming apparatus such as a copying machine, a printer, or a printing press, paper (also referred to as recording paper, sheet, etc.) on which image formation has been performed is conveyed to a post-processing device attached to the image forming apparatus, and post-processing such as binding and folding is performed. A configuration is known.
[0003] As a load mechanism provided in the post-processing device, there is one provided with a driven member that is driven to be reciprocally movable for alignment of means for performing post-processing. Such a load mechanism generally includes drive means having a drive source for moving the driven member to an arbitrary position and detection means for detecting the amount of movement of the driven member.
[0004] In addition, a configuration is known in which a home position (reference position) serving as a starting point when moving the driven member to a predetermined position is set, and a sensor or the like for detecting that the driven member has moved to the home position is provided. Further, for a reciprocally moving driven member, in addition to a home position sensor, a sensor is also required at a limit position on the other end side of the movement range.
[0005] However, when a sensor for detecting the driven member is provided for positioning the driven member, there are problems such as a need for an installation space for the sensor and routing of a harness, which increases costs.
[0006] On the other hand, in Patent Document 1, as a sorter capable of executing the initial operation of an indexer without using a home position sensor, means for outputting a pulsed clock signal for each rotation amount of a drive motor, a limit sensor disposed at one limit position of the movement range of a movable orientation means, means for counting the clock signal after the limit sensor operates, and control means for stopping the drive of the drive motor when the counting ends are disclosed. [Overview of the project] [Problems that the invention aims to solve]
[0007] Patent Document 1 describes that, of the home position sensor installed at one end of the movement range and the limit sensor installed at the limit position at the other end, the home position sensor can be omitted. However, since detection by the limit sensor at the other end is essential for sorter control, it is difficult to reduce the cost of installing positioning sensors.
[0008] Therefore, the present invention aims to provide a post-processing device that eliminates the need to install sensors for positioning a reciprocating driven member, thereby achieving cost reduction. [Means for solving the problem]
[0009] To solve the above problems, the present invention provides a post-processing device for performing post-processing on paper transported from an image forming apparatus, comprising: a driven member that moves back and forth in a predetermined direction; a driving means for moving the driven member; and stopper members disposed at both ends of the direction of movement of the driven member and defining the range of movement, wherein the driven member is moved until it contacts the stopper members, and one of the drive limit positions where the driven member stops is taken as a reference position, and when the driven member is moved to a predetermined position, the reference position is used as the starting point. Let the driving time required for the driven member to move throughout the entire movement range be T1, and the driving time for driving the driven member to move from an arbitrary position to the driving limit position be T2. When the relationship T1 < T2 is satisfied, it is determined that the driven member has reached the driving limit position. It is characterized by the following: [Effects of the Invention]
[0010] According to the present invention, it is possible to provide a post-processing device that eliminates the need to install sensors for positioning a reciprocating driven member, thereby achieving cost reduction. [Brief explanation of the drawing]
[0011]
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Embodiments for Carrying Out the Invention
[0012] Hereinafter, the post-processing device and the image forming system of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be changed within the scope that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc. As long as the functions and effects of the present invention are achieved in any aspect, it is included in the scope of the present invention.
[0013] (Image Forming System) FIG. 1 is a schematic configuration diagram showing the configuration of an image forming system according to an embodiment of the present invention. The image forming system 100 in FIG. 1 includes an image forming apparatus 101, an image reading apparatus 102, and a post-processing device 200 according to the present invention described later.
[0014] The image forming apparatus 101 such as a copying machine, a printer, or a printing machine has a configuration capable of forming an image by, for example, an electrophotographic method, and performs electrostatic latent image formation by optical writing on a latent image carrier, visible image processing of the latent image with toner, transfer and fixing of the toner image on paper. In addition, it includes an image reading apparatus 102 for reading a document and an automatic document feeder (ADF) 103 for taking in and transporting the document.
[0015] The electrostatic latent image is visible image processed by a developer supplied from a developing device in the image forming unit to form a toner image, and the toner image is transferred to paper fed from a paper feeding unit. The paper onto which the toner image has been transferred is conveyed to the post-processing device 200 after the toner image has been fixed.
[0016] The image forming apparatus 101 can be configured, for example, to operate as a copier that reads image information formed on the surface of an original document and copies it onto paper, or to form an image on the surface of paper P that has been sent from another terminal. The image forming apparatus according to this embodiment is not limited to a specific image forming method. The configurations of the image forming apparatus 101, image reading device 102, ADF 103, etc., are those of a typical image forming apparatus and will therefore not be explained.
[0017] (Post-processing device) Figure 2 shows a schematic side view of a post-processing device 200 according to one embodiment of the present invention. As shown in Figure 2, the post-processing device 200 has an introduction path 1 for receiving the image-formed paper P discharged from the image forming apparatus 101, three branching paths 2 that branch off from the introduction path 1, a straight transport path 3, and a downward transport path 4.
[0018] The introduction path 1 includes an entrance sensor 13 for detecting when paper P is brought in, an entrance roller 10, a horizontal transport roller 11 positioned downstream of the entrance roller 10 in the transport direction, and branching claws 7 and 8 as switching means for switching the transport direction from the introduction path 1 to the upper transport path 2, the straight transport path 3, and the lower transport path 4. When the paper P enters the introduction path 1, the control unit of the post-processing means 200 determines the necessary post-processing for the paper P based on instructions from the image forming system 100, and the entrance roller 10, horizontal transport roller 11, and branching claws 7 and 8 operate in accordance with the instructions from the control unit to change the transport path of the paper P.
[0019] The transport path 2 is the path for transporting the paper P to the proof tray 6, and constitutes the proof discharge section. In the proofing discharge section, the paper P, whose direction of travel has been changed by the branching claw 7 from the introduction path 1, is discharged directly into the proofing tray 6.
[0020] The shift discharge section is connected from the straight transport path 3 and consists of an intermediate transport roller 12 with a position-changeable shift mechanism, a paper discharge tray 5, a pair of opposing paper discharge rollers 26 and driven roller 27, and a paper discharge sensor 28. The paper P discharged from the straight transport path 3 is shifted by a certain amount in a direction perpendicular to the transport direction by the shift mechanism of the intermediate transport roller 12, and is then gripped by the paper discharge roller 26 and the driven roller 27 and discharged sequentially in stacks on the paper discharge tray 5.
[0021] When the paper P is held between the paper discharge roller 26 and the driven roller 27, the driven roller 27 or the paper discharge guide plate 29 equipped with the driven roller 27 moves toward and away from the paper discharge roller 26, allowing selection between a closed state in which the paper P can be discharged and an open state in which it is not held. After the paper P shift operation is completed, the shift discharge unit controls the distance between the paper discharge roller 26 and the driven roller 27 to the closed state, thereby holding and discharging the shifted paper P or the stack of sheets of paper P.
[0022] The shift discharge section also has a filler 40 near the top of the discharge opening. The filler 40 is rotatably positioned near the center of the paper P discharged into the output tray 5, and the tip of the filler 40 is in contact with the upper surface of the paper P. The filler 40 is equipped with a top-surface detection sensor for detecting the height of the leading edge 40a of the filler 40. When the sensor detects that the height of the leading edge of the filler 40 exceeds a predetermined value, the control unit lowers the output tray 5.
[0023] By lowering and raising the position of the output tray 5, stable paper output from the output slot is possible even when a large amount of paper P is being ejected. Furthermore, when the output tray 5 reaches its lower limit, i.e., the tray is full, the control unit can issue a stop signal to stop the image forming operation of the image forming system 100.
[0024] The edge stapling unit includes a staple tray 21, a return roller 41, a jogger 23 for aligning the paper P in the width direction, a rear end fence 24 for aligning the paper P in the length direction, and a stapler 50 as a stapling means. The edge stapling unit is designed to align and stack the paper P that has been transported to the staple tray 21 using a jogger 23 and a rear edge fence 24. The stack of aligned paper P is then stapled at the appropriate position on the lower edge of the stack by a stapler 50, which moves in a direction perpendicular to the paper surface by the stapler movement mechanism. The stack of paper P, which has been bound in this manner, is transported in the discharge direction by the discharge claw 29, and is held between the paper discharge roller 26 and the driven roller 27 before being discharged to the paper discharge tray 5.
[0025] The saddle stitching and folding processing unit is connected to the end of the lower transport path 4. When performing saddle stitching and folding on paper P, the paper P passes through the straight transport path 3, and the branching claw 8 is switched after the leading edge detection sensor 14 detects that the paper P has passed. When the branching claw 8 switches, the intermediate transport roller 12 rotates in the reverse direction, causing the paper P to switch back and be transported in the direction of the lower transport path 4.
[0026] The saddle-stitching and folding processing unit includes saddle-stitching transport rollers 61, 62, and 63, a saddle-stitching stapler 51 as a binding means, a folding stopper 64 for adjusting the folding position, a folding blade 71 that contacts the paper P and presses it in the direction of the paper to perform the folding process, and a folding plate 72.
[0027] The saddle-stitching and folding section also includes a saddle-folding paper discharge roller 73 located downstream of the folding plate 72 in the transport direction, and a saddle-stitching tray 9. When folding is performed by the folding blade 71 and the folding plate 72, the saddle-folding paper discharge roller 73 discharges the paper P into the saddle-stitching tray 9.
[0028] The perforation processing unit 30 is positioned on the path of the introduction path 1 and includes a resist detection means and a perforation processing means that performs perforation processing at a desired position on the paper P, taking into account the resist displacement detected by the resist detection means. If it is determined that perforation is necessary, the perforation processing unit 30 is used to perforate the appropriate location on the accepted paper P.
[0029] In this embodiment shown in Figure 2, the post-processing device 200 is shown to have both a saddle-stitching / folding processing unit and a perforating processing unit, but these components can be made detachable.
[0030] The post-processing device 200 according to this embodiment includes a load mechanism equipped with a reciprocating driven member, such as a stapler moving mechanism, a shift mechanism, a jogger mechanism, a paper folding stopper mechanism, and a paper folding blade mechanism. The following describes an example of applying the control of the movement of the driven member in the post-processing device according to the present invention to a stapler movement mechanism, but it can also be applied to other mechanisms mentioned above (shift mechanism, jogger mechanism, paper folding stopper mechanism, and paper folding blade mechanism, etc.).
[0031] Figure 3 is an explanatory diagram showing a stapler moving mechanism as an example of a load mechanism included in the post-processing means 200 of this embodiment. The driven member is a stapler 50. The post-processing device 200 of this embodiment is a post-processing device that performs post-processing on paper P transported from an image forming apparatus 101, and comprises a driven member (stapler 50) that moves back and forth in a predetermined direction, a driving means 56 for moving the driven member, and stopper members 53 (53a, 53b) disposed at both ends of the movement direction D1 of the driven member to define the range of movement. The driven member (stapler 50) is moved until it contacts the stopper member 53, and one of the drive limit positions where the driven member stops is taken as the reference position. When moving the driven member to a predetermined position, the reference position is taken as the starting point.
[0032] In Figure 3, "front side" F and "back side" B indicate the direction as seen from the user's perspective. The reference drive limit position is defined by the stopper member 53a on the front side, and the position where the driven stapler 50 comes into contact with the stopper member 53a and stops is also called the "home position." On the other hand, the position defined by the stopper member 53b on the rear side is also referred to as the "operation limit."
[0033] In Figure 3, the transport direction of paper P is indicated by D2, and the transport direction by AA. The stapler 50 is a component that moves along the moving axis 52 in a direction D1 perpendicular to the transport direction of the paper P, and performs stapling as a post-processing step at a predetermined position on the paper P.
[0034] The stapler mechanism includes a drive motor as a driving means 56 for moving the stapler 50 to any position within its reciprocating range. It also includes a pair of belt pulleys 54 and an endless belt 55 wound around the belt pulleys 54 as means for transmitting the driving force of the drive motor. As the drive motor rotates in forward and reverse directions, the endless belt 55 rotates in the corresponding direction, allowing the stapler 50 to reciprocate in the direction of D1.
[0035] Figure 3 shows the stapler 50, indicated by the solid line, in a waiting position at the home position. Before the paper P is transported, the drive motor is driven for a predetermined number of pulses to move the stapler 50 when it starts operating. After the paper P is transported to the staple tray 21, the stapler 50 performs edge stapling (stapling operation) at the predetermined position. After the stapling operation is complete, the stapler 50 returns to its home position and enters standby mode.
[0036] The stopper member 53a prevents the stapler 50 from moving forward of the home position. Similarly, the stopper member 53b prevents the stapler 50 from moving backward of the position indicated by the dashed line (operation limit position).
[0037] The following describes an example in which the stapler 50, which is the driven member, is moved until it comes into contact with the stopper member 53a, and the drive limit position just before the point where the stapler 50 stops is taken as the home position, and in which it is determined that the stapler 50 has reached the drive limit position.
[0038] (First Embodiment) Figure 4 is a block diagram showing an example of the configuration necessary for controlling the stapler movement mechanism in the control unit of the post-processing device according to this embodiment. As shown in Figure 4, the control unit is configured to include a CPU 80, a timer 81, and a motor driver 82. The CPU 80 moves the stapler 50 by driving the motor driver 82. To move the stapler 50 by a predetermined distance, the CPU 80 inputs a predetermined number of pulses corresponding to the input to the motor driver 82, or inputs pulses for a predetermined time period using the counting function of the timer 81.
[0039] Figure 5 shows the stapler 50 in the home position, which is the drive limit position of the front side F. Figure 6 shows the stapler 50 in the operating limit position (mechanical limit position), which is the drive limit position at the rear B. For reference, the stapler 50 in the home position is shown by a dashed line. The maximum travel distance Lmax represents the entire range of movement of the stapler 50, from the home position where it is in contact with the stopper member 53a to the operating limit position where it is in contact with the stopper member 53b.
[0040] Figure 7 is an explanatory diagram showing how to move the stapler 50 from the operating limit position (C2) to the home position (C1) in the direction indicated by D1. In this embodiment, when moving the stapler 50 to the home position, the drive is performed to move it a distance sufficiently longer than the maximum travel distance Lmax (for example, twice the distance of Lmax). Figure 8 shows the relationship between the position of the stapler 50 and the drive time when driven in this manner.
[0041] FIG. 8 is a graph when the stapler is moved from the operation limit position (C2) to the home position (C1) as shown in FIG. 7. At the driving time T1, the stapler 50 abuts against the stopper member 53a and stops at the home position. After that, even if the driving is continued up to T2, no change in position is observed from the home position. In the present embodiment, even if the driving is continued after the driven member, i.e., the stapler 50, abuts (collides) against the stopper member 53, appropriate design of the members, selection of materials, adjustment of the load magnitude, etc. are performed so that both members are not damaged.
[0042] In the post-processing apparatus of the present embodiment, the driving time required for the driven member to move over the entire movement range is T1, and the driving time for driving the driven member from an arbitrary position to the driving limit position is T2. When the relationship T1 < T2 is satisfied, it can be determined that the driven member has reached the driving limit position, that is, the stapler 50 has reached the home position.
[0043] FIG. 9 is a flowchart showing the flow of positioning of the driven member of the present embodiment. FIG. 9(A) is a flowchart when moving the stapler 50 to the home position, and FIG. 9(B) is a flowchart in the case of making a determination based on the driving time.
[0044] In the example of FIG. 9(A), first, the stapler 50 is driven to the front side F (S001). It is determined whether the driving distance exceeds the maximum distance Lmax shown in FIG. 7 (S002). If it does not exceed, the driving is continued, and if it exceeds, the driving is stopped (S003). The driving distance is preferably a distance sufficiently longer than the maximum movement distance Lmax. For example, it is preferable to use a distance twice that of Lmax as the determination criterion.
[0045] In the example in Figure 9(B), the decision in step S002 in Figure 9(A) is made based on the driving time. First, the stapler 50 is driven toward the front side F (S101). It is determined whether the driving time exceeds the driving time T1 required to move the entire range of motion (S102). If it does not exceed the range of motion, the driving continues; if it does exceed the range of motion, the driving stops (S103). Furthermore, it is preferable that the driving time be sufficiently longer than the time T1 required to travel the maximum travel distance Lmax. For example, it is preferable to use twice the time T1 as the criterion.
[0046] Thus, according to the post-processing device of this embodiment, the driven member can be moved to its home position based on the driving distance and driving time, and the starting point of the operation can be defined, without installing a sensor for positioning the reciprocating driven member. Since there is no need to install a sensor for positioning, cost reduction can be achieved.
[0047] Figure 10 is an explanatory diagram showing the state after defining the reference position of the stapler 50 using the method described above and moving the stapler 50 from the reference position to a predetermined position. In Figure 10, the stapler 50 located at the home position, which is the reference position, is shown by a dashed line. Figure 11 shows the flow of driving the stapler 50 from the home position to a predetermined position Ls.
[0048] The flowchart in Figure 11 shows the flow of operations that take place after, for example, step S003 in Figure 9(A) or step S103 in Figure 9(B). The stapler 50 is moved to its predetermined position by driving it from the home position towards the rear B (S201). It is determined whether the driving distance has reached a predetermined value (S202). If it has not reached the predetermined value, the driving continues; if it has reached the predetermined value, the driving stops (S203). Whether or not the driving distance has reached a predetermined value can be determined without using a sensor, based on the number of drive pulses of the drive motor or the length of the driving time.
[0049] (Second embodiment) Figure 12 is a block diagram showing an example of the configuration necessary for controlling the stapler movement mechanism in the control unit of the post-processing device according to this embodiment. As shown in Figure 12, the control unit is configured to include a CPU 80, a timer 81, a motor driver 82, and an encoder 83. The CPU 80 moves the stapler 50 by driving the motor driver 82. The encoder 83 outputs a pulse signal corresponding to the rotation of the motor driver 82. To move the stapler 50 by a predetermined distance, a predetermined number of pulses corresponding to the movement is input to the motor driver 82, or pulses are input for a predetermined time period using the counting function of the timer 81.
[0050] Figure 13 is an explanatory diagram showing an example of a motor equipped with an encoder applied to the drive means of this embodiment. Figure 13(A) is an example of a brushless DC motor equipped with an optical encoder, and Figure 13(B) is an example of a brushless DC motor with an encoderless position detection function, with the upper part being a schematic side view and the lower part being a perspective view.
[0051] The brushless DC motor 85 in Figure 13(A) has a driver IC 84 and an encoder 83 on the output shaft. On the other hand, the brushless DC motor 85 in Figure 13(B) has a driver IC 84, but the encoder 83 is located externally.
[0052] Figure 14 is a graph showing the feedback signal (encoder signal) from encoder 83 when the stapler is moved from the operating limit position (C2) to the home position (C1), as shown in Figure 7. At a driving time T1, the stapler 50 contacts the stopper member 53a, reaches the home position, and stops. Even if the driving continues until T2, there is no change in the encoder pulse. In this embodiment, even if the drive continues after the stapler 50, which is the driven member, comes into contact with (collides with) the stopper member 53, appropriate measures will be taken to ensure that neither member is damaged by the design of the members, the selection of materials, and the adjustment of the load.
[0053] The post-processing device of this embodiment includes an encoder 83 that outputs a pulse signal corresponding to the rotation of the motor 85 constituting the drive means, and drives the driven member to move to the drive limit position. It also receives a feedback signal from the encoder 83, and when the change in the feedback signal ceases, it can determine that the driven member has reached the drive limit position.
[0054] Figure 15 is a flowchart showing the positioning flow of the driven member in this embodiment, and shows the case where the decision in step S002 shown in Figure 9(A) is made based on the change in the encoder signal. In the example shown in Figure 15, first the stapler 50 is driven toward the front side F (S301). Then, it is determined whether there is an encoder pulse input (S302). If there is an encoder pulse input, the driving continues, and if there is no more encoder pulse input, the driving stops (S303).
[0055] While the stapler 50 is in operation, the encoder signal is constantly detected, and the position where the encoder pulse input is no longer detected can be set as the home position. The stapler 50 may be stopped immediately when the encoder pulse input is no longer detected, or it may be continued for a certain period of time after the input is no longer detected. Following step S303, the stapler 50 can be moved to the predetermined position according to the flow shown in Figure 11.
[0056] Thus, according to the post-processing device of this embodiment, the driven member can be moved to the home position and the starting point of the operation can be defined based on the driving distance and driving time, without installing a sensor for positioning the driven member that is moving back and forth. Since there is no need to install sensors for positioning, cost reductions can be achieved. Furthermore, the time spent driving beyond the drive limit position can be shortened compared to the method of the first embodiment, thereby reducing unnecessary load on the components.
[0057] (Third embodiment) Figure 16 is a block diagram showing an example of the configuration necessary for controlling the stapler movement mechanism in the control unit of the post-processing device according to this embodiment. As shown in Figure 16, the control unit is configured to include a CPU 80, a motor driver 82, and a DC motor 85. The CPU 80 moves the stapler 50 by driving the motor driver 82. The load current of the DC motor 85 is fed back to the CPU 80.
[0058] Figure 17 is an explanatory diagram showing the process of moving the stapler 50 from an arbitrary position to the home position in the direction indicated by D1. Figure 17(A) shows the state in which the stapler 50 is stopped at an arbitrary position other than the drive limit position, Figure 17(B) shows the state in which the stapler 50 is being driven toward the front side F, and Figure 17(C) shows the state in which the stapler 50 has collided with (come into contact with) the stopper member 53.
[0059] Figure 18 is a graph showing the current values of the load current fed back to the CPU in each of the following states: the stopped state in Figure 17(A), the driven state in Figure 17(B), and the collision state in Figure 17(C). The horizontal axis represents time. After the stapler 50 reaches the home position, the load increases when it collides with the stopper member 50a and stops, causing the feedback current value to rise. By setting a threshold value in advance based on the current value that rises after reaching the home position, that threshold can be used as the judgment criterion.
[0060] The post-processing device of this embodiment drives the driven member to move it to the drive limit position and receives feedback of the current value from the motor 85 that constitutes the driving means. When the current value exceeds a preset threshold due to an increase in the load on the motor 85, it can determine that the driven member has reached the drive limit position.
[0061] Figure 19 is a flowchart showing the positioning flow of the driven member in this embodiment, and shows the case where the decision in step S002 shown in Figure 9(A) is made based on the change in the fed-back current value. In the example shown in Figure 19, first the stapler 50 is driven towards the front side F (S401). Then, it is determined whether the current value exceeds a preset standard (S402). If the threshold is not exceeded, the driving continues; if the threshold is exceeded, the driving stops (S403).
[0062] While the stapler 50 is in operation, the current value is constantly detected, and the position where the feedback current value exceeds a threshold can be set as the home position. Following step S403, the stapler 50 can be moved to a predetermined position according to the flow shown in Figure 11.
[0063] Thus, according to the post-processing device of this embodiment, the driven member can be moved to the home position based on the driving distance and driving time, and the starting point of the operation can be defined, without installing a sensor for positioning the reciprocating driven member. Since there is no need to install a sensor for positioning, costs can be reduced. In addition, the time spent driving beyond the driving limit position can be shortened compared to the method of the first embodiment, and unnecessary load on the components can be reduced. [Explanation of symbols]
[0064] 50 Driven member (stapler) 52 Movement axis 53 Stopper member 54 Belt Pulley 55 Endless belt 56 Driving means 100 Image Forming Systems 101 Image forming apparatus 200 Post-processing equipment [Prior art documents] [Patent Documents]
[0065] [Patent Document 1] Japanese Patent Application Publication No. 8-290865
Claims
1. A post-processing device that performs post-processing on paper transported from an image forming apparatus, A driven member that moves back and forth in a predetermined direction, A driving means for moving the driven member, The driven member comprises stopper members disposed at both ends in the direction of movement of the driven member, which define the range of movement, The driven member is moved until it contacts the stopper member, and one of the drive limit positions where the driven member stops is taken as the reference position. When moving the driven member to a predetermined position, the reference position is used as the starting point. A post-processing device characterized in that, T1 is the driving time required for the driven member to move across the entire range of motion, and T2 is the driving time required to move the driven member from an arbitrary position to the driving limit position, and when the relationship T1 < T2 is satisfied, it is determined that the driven member has reached the driving limit position.
2. The drive means includes an encoder that outputs a pulse signal corresponding to the rotation of the motor, The post-processing device according to claim 1, characterized in that it drives the driven member to move to the drive limit position, receives a feedback signal from the encoder, and determines that the driven member has reached the drive limit position when the change in the feedback signal ceases.
3. The post-processing device according to claim 1, characterized in that it drives the driven member to move to the drive limit position, receives feedback of the current value from the motor constituting the driving means, and determines that the driven member has reached the drive limit position when the current value exceeds a preset threshold due to an increase in the load on the motor.
4. An image forming system comprising an image forming apparatus and a post-processing apparatus according to any one of claims 1 to 3.