Aftertreatment Device

Abstract

To provide a post-processor allowing for reducing power consumption and suppressing operation sound in a punch system.SOLUTION: A post-processor comprises a punch unit that perforates a sheet, a motor for perforation that drives the punch unit, and a post-processing control unit that controls the driving of the motor for perforation, thereby performing post-processing on a sheet on which an image is formed by an image forming apparatus. The post-processing control unit sets a first current value (1.8A) for driving the motor for perforation in a perforation section from a first position for the punch unit to start perforating the sheet to a second position to end the perforation and sets a second current value (0.9A) lower than the first current value in a non-perforation section except for the perforation section ((b-1)(i), (b-2)(i)).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a post-processing device, for example, a sheet post-processing device equipped with a sheet punching device that punches binding holes in sheets on which images are formed by an image forming device such as a copier or printer, and an image forming device equipped with the sheet post-processing device. [Background technology]

[0002] Conventionally, there has been a punch system equipped with a punch, a punch moving means, a registration member, and a sheet edge position detecting means. The punch punches holes in a sheet being conveyed. The punch moving means moves the punch in a direction perpendicular to the sheet conveyance direction. The registration member corrects sheet skew. The sheet edge position detecting means detects the edge position of the sheet perpendicular to the sheet conveyance direction. In such a punch system, a technique has been proposed in which the punch is moved to match the edge position of the sheet and then punches holes at a predetermined position in the sheet (see, for example, Patent Document 1). Another technique has been proposed, for example, using a rotary punch to punch holes without stopping the sheet conveyance (see, for example, Patent Document 2). Currently, a punch system has been devised that combines the above mechanisms to detect sheet skew without using a registration member, and moves the rotary punch to match the edge position of the sheet and punches holes at a predetermined position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-279170 [Patent Document 2] U.S. Patent No. 10,071,494 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional punch systems, the rotary punch and punch moving means are both driven by separate motors, resulting in a problem of high power consumption for the entire punch unit. Furthermore, when the rotary punch is driven by a stepping motor, the torque required when punching a sheet, i.e., when the punch teeth are engaged with the sheet, differs from when not punching. Therefore, if the current value is set to output the torque required for punching, there is a problem of loud operating noise when not punching.

[0005] The present invention has been made under these circumstances, and has an object to reduce power consumption and operating noise in a punch system. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention has the following configuration. (1) A post-processing device that includes a punching device that punches holes in a sheet, a first motor that drives the punching device, and a control device that controls the driving of the first motor, and that performs post-processing on a sheet on which an image has been formed by an image forming device, a moving means for moving the punching means in a width direction perpendicular to a sheet conveying direction, a second motor for driving the moving means, a first detecting means for detecting that the sheet has reached the post-processing device, a second detecting means for detecting the position of an end of the sheet in the width direction, and a calculating means for calculating a distance for moving the punching means to a predetermined position by the moving means based on a detection result of the second detecting means, The control means sets a first current value for driving the first motor in a first section from a first position where the punching means starts punching a sheet to a second position where the punching means finishes punching, and sets a second current value lower than the first current value in a second section excluding the first section. a third current value is set to drive the second motor when the moving means moves the punching means in the width direction; a fourth current value lower than the third current value is set to keep the punching means stopped at the predetermined position in the width direction by the moving means; when the first detecting means detects that the sheet has reached the post-processing device, the second current value is set to the first motor; and when the calculating means calculates the distance, the third current value is set to the second motor. A post-processing device characterized by: (2) A post-processing device that performs post-processing on a sheet on which an image has been formed by an image forming device, the post-processing device comprising: a punching means for punching holes in a sheet; a first motor for driving the punching means; and a control means for controlling the driving of the first motor. The post-processing device further comprises: a moving means for moving the punching means in a width direction perpendicular to the sheet conveying direction; and a second motor for driving the moving means. The control means sets a first current value for driving the first motor in a first section from a first position where the punching means starts punching holes in the sheet to a second position where the punching means finishes punching the sheet. a second current value lower than the first current value is set in a second section excluding the first section; a third current value is set to drive the second motor when the moving means moves the perforation means in the width direction; a fourth current value lower than the third current value is set to maintain the perforation means stopped at a predetermined position in the width direction by the moving means; the current values ​​of the first motor and the second motor are changed in stages; and while the current value of one motor is being changed, the current value of the other motor is not changed. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce power consumption and suppress operating noise in a punch system. [Brief explanation of the drawings]

[0008] [Figure 1] Configuration diagram of post-processing device and image forming device in embodiments 1 and 2 [Figure 2] Block diagram of post-processing device and image forming device according to first and second embodiments [Figure 3] Cross-sectional view of the punch unit of Examples 1 and 2 [Figure 4] 10A and 10B are diagrams showing the movement and punching operations of the punch unit in the first and second embodiments. [Figure 5] FIG. 10 is a diagram showing a sequence of current setting for each motor in the first embodiment. [Figure 6] Flowchart showing the control of the first embodiment [Figure 7] Flowchart showing the control of the second embodiment DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. [Example]

[0010] <Explanation of the configuration of the post-processing device and image forming device> FIG. 1 is a cross-sectional view showing the configuration of an electrophotographic image forming apparatus 1 and a post-processing device 4. In FIG. 1, the up-down direction is indicated by a double-headed arrow. The post-processing device 4 performs various post-processing operations, such as punching and stapling, on sheets P on which images have been formed by the image forming apparatus 1. The image forming apparatus 1 is equipped with a paper feeder 6 that stores multiple sheets P and feeds the sheets P one by one. The type of sheet P fed from the paper feeder 6 is identified (thin paper, regular paper, thick paper, basis weight, etc.) by a paper type sensor 111 located in the transport path. The sheet P is transported to a photosensitive drum 9, an image carrier rotatably supported in a cartridge 8, and a transfer roller 10, a transfer means to which a predetermined voltage is applied. Inside the cartridge 8, the photosensitive drum 9 undergoes exposure, charging, latent image formation, and development processes, and a toner image is formed on the surface of the photosensitive drum 9. The latent image is formed by a laser scanner unit 15 that scans the sheet P with laser light in a direction (main scanning direction) perpendicular to the conveying direction of the sheet P using a rotary polygon mirror and a lens to form the latent image.

[0011] The sheet P on which the unfixed toner image has been formed passes through a fixing unit 11, which heats and pressurizes the toner on the sheet P to fix it, and is then discharged onto the discharge tray 7. When the sheet P is discharged to the post-processing device 4, it is sent to a horizontal conveying section 14 after passing through the fixing unit 11. The sheet P conveyed from the horizontal conveying section 14 is delivered to a punch inlet roller 21 of the post-processing device 4. An inlet sensor 27, which is a first detection means, is disposed downstream in the conveying direction of the punch inlet roller 21 (hereinafter simply referred to as downstream). The inlet sensor 27 is disposed to detect the timing at which the leading or trailing edge of the sheet P received by the punch inlet roller 21 passes, and to detect whether or not a paper jam has occurred.

[0012] Downstream of the entrance sensor 27 are disposed a rotary punch unit 62, which serves as a punching means; a line sensor 61, which serves as a second detection means and is composed of multiple light-receiving elements; and a light-emitting unit 63. The punch unit 62 is composed of a punch 202 and a die 205, as shown in FIG. 3. The line sensor 61 and the light-emitting unit 63 face each other, and light from the light-emitting unit 63 is uniformly irradiated onto the line sensor 61. When the conveyed sheet P enters between the line sensor 61 and the light-emitting unit 63, the light irradiated from the light-emitting unit 63 is blocked, and the position of the blocked light-receiving element is detected as the position of the edge of the sheet P (hereinafter referred to as the edge position). A punch unit moving unit 104, which serves as a moving means shown in FIG. 2, moves the punch unit 62 in a direction perpendicular to the conveyance direction (hereinafter also referred to as the width direction) based on the edge position of the sheet P detected by the line sensor 61. After the punch unit 62 moves to a predetermined position, the post-processing control unit 101 rotates the punch unit 62 to punch holes in the sheet P. The punching operation of the punch unit 62 will be described in detail in <Function and Configuration> and <Movement and Punching of Punch Unit>.

[0013] After being punched by the punch unit 62, the sheet P is conveyed by punch outlet rollers 22 and 24, which are rotated by a drive source (not shown), and discharged onto the upper tray 25. In addition to the upper tray 25, a lower tray 37 is also arranged within the post-processing device 4, providing multiple trays as discharge destinations for the sheet P. These two trays are raised and lowered by a drive source (not shown) according to the quantity of the stack of sheets P loaded on the tray (the thickness of the stack of multiple sheets P (hereinafter also referred to as the sheet stack)). When the discharge destination of the sheet P is the lower tray 37, the conveyance of the sheet P is temporarily stopped just before it is discharged onto the upper tray 25. The sheet P is switched back by roller 24 and conveyed to roller 26. The sheet P is conveyed to the intermediate stacking section 39 by rollers 26, 28, and 29, which are rotated by a drive source (not shown). The sheets P are aligned in the conveyance direction and width direction within the intermediate stacking section 39, and after a predetermined number of sheets P have been aligned, a stapler (not shown) performs a binding operation. Thereafter, a discharge guide 34 connected to a guide driving section 35 moves parallel to the direction of discharge rollers 36 to push out the sheet stack, and the sheet stack is discharged onto a lower tray 37. The operation panel 110 is operated by the user to manually set the size and type (paper grade) of the sheets P. The image forming apparatus 1 and the post-processing apparatus 4 are controlled based on the information set using the operation panel 110.

[0014] <Functions and Configuration> FIG. 2 is a block diagram illustrating the functions and configuration of the image forming apparatus 1 and post-processing apparatus 4 shown in FIG. 1. Here, only the portions related to punching control of sheets P are explained. The post-processing apparatus 4 includes a post-processing control unit 101 that controls the sheet punching operation, the movement of the punch unit 62, and the detection operation of the edge position of sheets P. The post-processing control unit 101, which serves as a control unit, includes a motor control unit 105, a motor driver circuit 115 for punching, a motor driver circuit 114 for adjusting the edge position, a movement distance calculation unit 107 for the punch unit 62, an edge position detection unit 113, and a sensor control unit 108. The image formation control unit 109 has a function of controlling image formation of the image forming apparatus 1. The image formation control unit 109 includes a paper type discrimination unit 112, which receives a paper type detection signal that is the detection result of a paper type sensor 111. The image formation control unit 109 also acquires (receives) paper type information, which is information regarding the paper type of sheets P, input using an operation panel 110. The image forming control unit 109 is capable of receiving and transferring the sheet P that is transported in synchronization with the post-processing control unit 101, and is capable of transmitting paper type information of the sheet P and paper type information based on a paper type detection signal to the post-processing control unit 101.

[0015] The motor control unit 105 controls the punching motor driver circuit 115 and the edge position adjustment motor driver circuit 114 by setting currents and issuing drive instructions to these circuits. As a result, the motor control unit 105 drives each motor under predetermined drive conditions (drive frequency, current setting, excitation method, etc.). Hereinafter, the two motors described in Example 1 (the punching motor 102 and the edge position adjustment motor 103) will be described as stepping motors. The punching motor driver circuit 115 drives the first motor, the punching motor 102, to rotate the punch unit 62. The edge position adjustment motor driver circuit 114 drives the second motor, the edge position adjustment motor 103, to move the punch unit movement unit 104 in the width direction.

[0016] The sensor control unit 108 detects the presence or absence of a sheet P from a change in the output signal of the entrance sensor 27 (hereinafter also referred to as an entrance sensor signal), and outputs the detection result to the motor control unit 105. The edge position detection unit 113 sends a light emitting signal to the light emitting unit 63 to cause the light emitting unit 63 to emit a predetermined amount of light, and detects the edge position of the sheet P from the output signal of multiple elements output from the line sensor 61 (hereinafter also referred to as a line sensor signal). The movement distance calculation unit 107 of the punch unit 62, which is a calculation means, determines (calculates) the movement distance (distance) of the punch unit 62 from information on the edge position of the sheet P detected by the edge position detection unit 113, and outputs the calculation result to the motor control unit 105. The functions and configurations of the image forming apparatus 1 and the post-processing apparatus 4 have been described above.

[0017] <Punch unit perforation section> Next, the punch unit 62 will be described with reference to FIG. 3. The conveyance direction of the sheet P is also indicated by an arrow in FIG. 3. In FIG. 3, the punch unit 62 has a punch 202 and a die 205 each axially supported by a casing (not shown). Gears (not shown) fixed to one end of the support shaft 65 of the punch 202 and one end of the support shaft 66 of the die 205 mesh with a gear (not shown) provided on the output shaft of the perforation motor 102. The perforation motor 102 is configured to rotate the punch 202 clockwise and the die 205 counterclockwise in synchronization with each other in FIG. 3. The die 205 has a die hole 206 provided at a position corresponding to the punch 202. (a), (b), (c), and (d) of FIG. 3 show how the sheet P is perforated over time by the punch unit 62, which is a perforation device.

[0018] FIG. 3(a) shows that the rotational position of the punch 202 is at the home position. Here, the position shown in FIG. 3(c) where the sheet P is punched is referred to as the punching position, and the position of the imaginary line connecting the support shafts 65 and 66 is referred to as the punching center position. In FIG. 3(a), the punch 202 is located forward in the rotational direction from the punching center position by the angle indicated by the arrow 67. The punch 202 is usually stopped at this position and waits for the conveyed sheet P. Even if the punch 202 is stopped at the home position, it does not interfere with the conveyance of the sheet P. FIG. 3(b) shows that the rotational position of the punch 202 is at the punching start position 70, which is the first position where punching of the sheet P begins. FIG. 3(c) shows the position where the punch 202 and the die hole 206 just engage and the sheet P is punched, which is the punching position described above. FIG. 3(d) shows that the rotational position of the punch 202 is at the punching end position 71, which is the second position where punching is completed.

[0019] The motor control unit 105 starts the rotational driving of the punch unit 62, which has been kept waiting at the home position, by the motor 102 at a predetermined timing in synchronization with the timing at which the leading edge position of the sheet P is detected by the entrance sensor 27 via the sensor control unit 108. Furthermore, the motor control unit 105 matches the conveyance speed of the sheet P with the rotational speed of the punch unit 62, making it possible to punch holes at desired positions on the sheet P without stopping the conveyance of the sheet P. The punching section, which is the first section from the first position to the second position of the punch unit 62, has been described above.

[0020] <Punch unit movement and punching> Next, the movement operation of the punch unit 62 will be described using an example of punching, for example, three holes in a plurality of sheets P that are conveyed at an angle. The same case will also be used for the following <Regarding motor power and operating noise>, <Method for reducing power and operating noise>, and <Flowchart of punching and movement operation>.

[0021] 4(a) to 4(h) are diagrams showing, as viewed from above the post-processing device 4, the flow of a series of operations in which the punch unit 62, indicated by the two-dot chain line, moves and punches holes in the sheet P after the sheet P is transported from the image forming device 1 to the post-processing device 4. The dashed-dotted line 502 indicates the center position of the punch 202 in the width direction, and the dashed-dotted line 501 indicates the center position of the punch unit 62 in the transport direction of the sheet P. The intersection point 503 between the dashed-dotted line 502 and the dashed-dotted line 501 indicates the center of the punch position of the punch unit 62 at each timing. In FIG. 4, 504, 505, and 506 indicate, with dashed lines, the ideal positions (predetermined positions) of the first, second, and third holes in the first sheet P. In FIG. 4, 507, 508, and 509 indicate, with solid lines, the actual positions of the first, second, and third holes in the first sheet P after punching. In FIG. 4(h), 510 indicates the ideal position of the first hole on the second sheet by a dashed line.

[0022] FIG. 4(a) shows the state where the leading edge of the sheet P has reached the inlet sensor 27. When the inlet sensor signal from the inlet sensor 27 changes, the motor control unit 105 drives the perforation motor 102 at a predetermined drive frequency to rotate the punch unit 62. The drive frequency is determined in advance based on the conveyance speed of the sheet P, and the punch unit 62 will perforate a hole at the ideal position when the perforation motor 102 rotates a predetermined number of steps. At this time, it is desirable for the punch unit 62 to wait at a nominal perforation position corresponding to the size of the sheet P being conveyed, in the width direction of the sheet P. Furthermore, the punch unit 62 waits at the home position described above before the sheet P is conveyed to the post-processing device 4, and is then moved to the nominal perforation position for the sheet P being conveyed.

[0023] 4(b) shows a state in which the ideal first hole 504 has reached the light-emitting unit 63 and the line sensor 61. The post-processing control unit 101 detects the timing at which the ideal hole position reaches the light-emitting unit 63 and the line sensor 61 based on the detection result of the inlet sensor 27. At this time, the edge position detection unit 113 detects the actual edge position of the sheet P based on the line sensor signal of the line sensor 61. The movement distance calculation unit 107 of the punch unit 62 calculates the difference E1 between the actual edge position of the sheet P detected by the edge position detection unit 113 and the ideal position. The edge position detection unit 113 determines the calculated difference E1 as the movement distance of the punch unit 62.

[0024] FIG. 4(c) shows a state in which the motor control unit 105 has moved the punch unit 62 in the width direction of the sheet P by the distance of difference E1 using the punch unit moving unit 104. After the punch unit 62 has moved by the distance E1, the motor 103 for adjusting the edge position is energized and stopped. FIG. 4(d) shows a state in which the punch unit 62 has completed punching the first hole 504. FIG. 4(e) shows a state in which the ideal second hole 505 has reached the light-emitting unit 63 and the line sensor 61. In the same manner as for the first hole, the difference E2 between the actual edge position of the sheet P and the ideal position is determined as the movement distance. FIG. 4(f) shows a state in which the motor control unit 105 has moved the punch unit 62 in the width direction of the sheet P by the distance of difference E2 using the punch unit moving unit 104. As with the first hole, after the punch unit 62 has moved, the motor 103 for adjusting the edge position is energized and stopped.

[0025] FIG. 4(g) shows the state after punching of the second hole 508 is completed. After punching of the second hole 508, the punching operation for the third hole is performed in a similar manner. FIG. 4(h) shows the state after the ideal first hole 510 of the second sheet has reached the light-emitting unit 63 and the line sensor 61. The difference E3 is determined in the same manner as for the first sheet P. The motor control unit 105 uses the punch unit moving unit 104 to move the punch unit 62 by the distance of the difference E3 from the position of the third hole in the first sheet P toward the center in the width direction, and punches the first hole in the second sheet P. The movement and punching of the punch unit 62 have been described above.

[0026] <Motor power and operating noise> Next, we will explain the issues of motor power and operating noise. Figure 5 (a) is a diagram showing the current settings of the punching motor 102 and the edge position adjustment motor 103 when a constant current is set for each motor, and the total current setting for both, on the time axis. (i) shows the current (A) set for the punching motor 102, (ii) shows the current (A) set for the edge position adjustment motor 103, and (iii) shows the total current (A) set for (i) and (ii). The horizontal axis indicates time (t) in all cases. Furthermore, sheet 1 indicates the first sheet P, and sheet 2 indicates the second sheet P.

[0027] 3(d) is defined as the punching section, and the other angle (360°-θ) is defined as the non-punching section, which is a second section excluding the punching section. In addition, when the punch unit moving section 104 is moved, it is referred to as being driven, and when it is not moved, it is referred to as being non-driven.

[0028] The current setting of 1.8 [A] for the punching motor 102 is a setting that allows the motor torque required to punch the sheet P to be output. The current setting of 0.6 [A] for the edge position adjustment motor 103 is a setting that allows the motor torque required to drive the punch unit moving section 104 to be output. 1.8 [A] is a current setting that allows the motor torque required to punch paper types, such as cardboard and glossy paper, to be output. As shown in FIG. 5(a), if a constant current is applied to the motors 102 and 103 regardless of whether punching or non-punching is being performed, the total current setting becomes large at 2.4 [A]. In this case, the punching motor 102 only needs to be able to output the motor torque required to drive the punch unit 62 during the non-punching section. Therefore, the motor 102 will flow with more current than necessary during the non-punching section. Flowing more current than necessary increases the vibration amplitude of the motor 102 itself during the non-punching section, resulting in louder operating noise from the motor 102.

[0029] On the other hand, the non-driving section of the motor 103 for adjusting the edge position is only required to output the holding torque necessary to stop the punch unit moving section 104, i.e., to maintain the stopped state of the punch unit 62 in the width direction. For this reason, more current than necessary flows through the motor 103 in the non-driving section. The above has explained the power and operating noise of the motor.

[0030] <Methods for reducing power consumption and operating noise> Next, a method for reducing motor power and operating noise will be described. In (b-1) and (b-2) of FIG. 5, the current setting of the drilling motor 102 is set to 0.9 [A] for at least a portion of the non-drilling section. The current setting of the end position adjustment motor 103 is set to 0.1 [A] for the non-driving section. The current settings of each motor and the total current setting are shown on the time axis. (i) to (iii) are similar to FIG. 5(a). Specifically, the drilling motor 102 is set to a first current value of 1.8 [A] in at least the section including the drilling section, and is set to a second current value of 0.9 [A] lower than the first current value in at least a portion of the non-drilling section. The end position adjustment motor 103 is set to a third current value of 0.6 [A] in the driving section, and is set to a fourth current value of 0.1 [A] lower than the third current value in the non-driving section.

[0031] 5(b-1) shows a case where the current settings of the drilling motor 102 and the end position adjustment motor 103 are instantaneously changed. In (b-1), it is desirable to set the current to 1.8 [A] before entering the drilling section to prevent insufficient motor torque during drilling. Therefore, the current is set to 1.8 [A] in a section wider than the drilling section, such as section 80. (b-2) shows a case where the current settings are changed with a gradient before and after the drilling section, i.e., in stages. The current settings may be changed in this manner. In this case, the post-processing control unit 101 changes the current values ​​of the drilling motor 102 and the end position adjustment motor 103 in stages, but while changing the current value of one motor, the current value of the other motor is not changed.

[0032] By controlling in this manner, the total current value in the punching and non-driving sections is 1.9 A, and the total current value in the non-punching and driving sections is 1.5 A, both of which are lower than the total current value of 2.4 A in Figure 5(a). Note that the space between the third hole in Sheet 1 and the first hole in Sheet 2 is between the rear end of Sheet 1 and the front end of Sheet 2 (paper gap). In both Figures 5(b-1) and (b-2), the current setting for motor 102 is 0.9 [A], the current setting for motor 103 is 0.1 [A], and the total current setting is 1.0 [A].

[0033] As shown in Figure 5, by preventing overlapping of the change periods of the current settings of the drilling motor 102 and the end position adjustment motor 103, both the peak and average of the total current setting can be reduced using either method (b-1) or (b-2). In addition, the current of the drilling motor 102 in the non-punching section can be reduced, which also reduces the operating noise of the motor. The method for reducing power consumption and operating noise has been described above.

[0034] <Flowchart of drilling and moving operations> Next, a flowchart of the punching operation and the movement operation of the punch unit 62 will be described with reference to FIG. 6. In step (hereinafter, S) 601, the post-processing control unit 101 is notified by the image formation control unit 109 that a sheet P has been fed from the sheet feeder 6. In S602, the post-processing control unit 101 causes the edge position detection unit 113 to light up the light-emitting unit 63 and starts monitoring the line sensor signal of the line sensor 61. In S603, the post-processing control unit 101 determines via the sensor control unit 108 whether the inlet sensor 27 has detected the sheet P. If the post-processing control unit 101 determines in S603 that the sheet P has been detected, the process proceeds to S604; if it determines that the sheet P has not been detected, the process returns to S603. In S604, the post-processing control unit 101 drives the punching motor 102 at a current setting of 0.9 [A] via the motor control unit 105 and the punching motor driver circuit 115. The post-processing control unit 101 drives the motor 103 for adjusting the edge position with a current setting of 0.1 [A].

[0035] In S605, the post-processing control unit 101 obtains the detection result of the edge position of the sheet P from the edge position detection unit 113, and calculates the movement distance of the punch unit 62 (the difference from the ideal position) from the movement distance calculation unit 107. In S606, the post-processing control unit 101 sets the current setting of the edge position adjustment motor 103 to 0.6 [A] and moves the punch unit 62 the movement distance calculated in S605. In S607, after the movement of the punch unit 62 has finished, the post-processing control unit 101 changes the current setting of the edge position adjustment motor 103 to 0.1 [A] and stops it. In S608, after the inlet sensor 27 detects the sheet P via the sensor control unit 108, the post-processing control unit 101 rotates the punching motor 102 by a predetermined number of steps, changes the current setting of the punching motor 102 to 1.8 [A], and punches a hole in the sheet P.

[0036] In S609, the post-processing control unit 101 determines whether three holes have been punched in the sheet P. The post-processing control unit 101 has a counter (not shown) that counts the number of times punching has been performed and manages the number of holes punched. If the post-processing control unit 101 determines in S609 that punching of three holes has not been completed, the process returns to S605, and if it determines that punching of three holes has been completed, the process proceeds to S610. In S610, the post-processing control unit 101 determines whether there is a sheet P being transported subsequently (hereinafter referred to as a subsequent sheet). If the post-processing control unit 101 determines in S610 that there is a subsequent sheet, the process returns to S605, and if it determines that there is no subsequent sheet, the process ends. The flowchart of the drilling and moving operation has been described above.

[0037] In this way, in the first embodiment, in a punch system that moves the punch unit 62 at punching intervals to punch holes, the power consumption of the punch system can be reduced and the operating noise of the punching motor 102 in the non-punching section can be reduced. As described above, according to the first embodiment, it is possible to reduce power consumption and suppress operating noise in the punch system. [Example]

[0038] In the second embodiment, the details of setting the optimum current for the punching motor 102 during punching, as described in the first embodiment, according to the paper type, will be described. This will enable further power savings in the punching system. The movement and punching operations of the post-processing device 4, the image forming device 1, and the punching unit 62 are the same as those in the first embodiment, so the details will not be described here.

[0039] <Determining the current setting for the drilling section> The following describes a method for converting paper type information acquired by the post-processing control unit 101 from the image formation control unit 109 into a current setting for the punching section and changing the current setting in the punching section. The paper type information can be acquired in either of the following two ways.

[0040] The first method uses a paper type detection signal output from a paper type sensor 111, which is a third detection means. The post-processing control unit 101 changes the current value of the punching motor 102 in the punching section depending on the paper type of the sheet P detected by the paper type sensor 111. In FIG. 2, the image formation control unit 109 includes a paper type discrimination unit 112 that converts the paper type detection signal output from the paper type sensor 111 into paper type information. The paper type sensor 111 uses, for example, an ultrasonic sensor to irradiate ultrasonic waves onto the sheet P and determines, for example, the basis weight of the sheet P based on the sound wave level of the ultrasonic waves that have passed through the sheet P. In this way, the basis weight of the sheet P may be used as the paper type information. Alternatively, an optical sensor that detects the surface properties of the sheet P may be used in addition to the ultrasonic sensor, and the paper type information may be converted based on the basis weight and surface properties of the sheet P. The second method uses paper type information input by the user to an operation panel 110, which is an input means. The post-processing control unit 101 changes the current value of the punching motor 102 in the punching section in accordance with the paper type of the sheet P input via the operation panel 110.

[0041] The image formation control unit 109 outputs the paper type information converted by the paper type discrimination unit 112 or the paper type information input from the operation panel 110 to the post-processing control unit 101. The post-processing control unit 101 determines the current setting for the perforation section of the perforation motor 102 based on the paper type information input from the image formation control unit 109.

[0042] For example, a current setting corresponding to paper type information such as that shown in Table 1 may be used. Note that information (e.g., a table) associating paper type information with current settings may be stored in advance in a storage unit (not shown) included in the post-processing control unit 101. [Table 1] Here, the first column of Table 1 shows the paper type (A to J), and the second column shows the current setting (A). For example, assume that the paper type of sheet P is "paper type A" based on the paper type information converted by paper type discrimination unit 112 or the paper type information input from operation panel 110. In this case, motor control unit 105 sets the current setting for the punching motor 102 in the punching section to 1.8 A. The determination of the current setting for the drilling section has been described above.

[0043] <Flowchart of drilling and moving operations> Next, the flowchart shown in FIG. 7 of the second embodiment will be described. The same processes as those described in FIG. 6 of the first embodiment are assigned the same step numbers, and descriptions thereof will be omitted. In S611, the post-processing control unit 101 acquires paper type information output from the image formation control unit 109 and converts it into a current value corresponding to the paper type information based on, for example, Table 1 (determines the set current). In addition, in S612, the post-processing control unit 101 sets the current setting for the punching motor 102 determined in S611. As a result, the post-processing control unit 101 can change the current setting for the punching motor 102 to a setting corresponding to the paper type information and punch a hole in the sheet P. The flowchart of the drilling and moving operation has been described above.

[0044] As described above, according to the second embodiment, the current for the punching motor 102 during punching can be changed to an optimum current setting depending on the paper type, thereby making it possible to further reduce power consumption. As described above, according to the second embodiment, it is possible to reduce power consumption and suppress operating noise in the punch system. [Explanation of symbols]

[0045] 1. Image forming device 4. After-treatment device 62 Punch unit 101 Post-processing control unit 102 Drilling motor

Claims

1. A punching means for punching holes in the sheet; a first motor for driving the punching means; A control means for controlling the driving of the first motor; A post-processing device that performs post-processing on a sheet on which an image is formed by an image forming device, a moving means for moving the punching means in a width direction perpendicular to a sheet conveying direction; a second motor for driving the moving means; a first detection means for detecting that a sheet has reached the post-processing device; a second detection means for detecting a position of an end portion of the sheet in the width direction; a calculation means for calculating a distance for moving the punching means to a predetermined position by the moving means based on a detection result of the second detection means; Equipped with The control means a first current value for driving the first motor is set in a first section from a first position where the punching means starts punching a sheet to a second position where the punching means finishes punching, and a second current value lower than the first current value is set in a second section excluding the first section; a third current value is set to drive the second motor when the moving means moves the punching means in the width direction, and a fourth current value lower than the third current value is set to maintain the punching means stopped at the predetermined position in the width direction by the moving means; when the first detection means detects that the sheet has reached the post-processing device, the second current value is set for the first motor; a third current value set for the second motor when the distance is calculated by the calculation means.

2. 2. The post-processing device according to claim 1, wherein the control means sets the fourth current value to the second motor after the moving means has moved the punching means by the distance.

3. 3. The post-processing device according to claim 2, wherein the control means sets the first current value to the first motor when the moving means stops the punching means at the predetermined position.

4. A punching means for punching holes in a sheet; a first motor for driving the punching means; A control means for controlling the driving of the first motor; A post-processing device that performs post-processing on a sheet on which an image is formed by an image forming device, a moving means for moving the punching means in a width direction perpendicular to a sheet conveying direction; a second motor for driving the moving means; Equipped with The control means a first current value for driving the first motor is set in a first section from a first position where the punching means starts punching a sheet to a second position where the punching means finishes punching, and a second current value lower than the first current value is set in a second section excluding the first section; a third current value is set to drive the second motor when the moving means moves the punching means in the width direction, and a fourth current value lower than the third current value is set to maintain the punching means stopped at a predetermined position in the width direction by the moving means; a current value of the first motor and a current value of the second motor being changed in a stepwise manner, while the current value of one of the motors is being changed, the current value of the other motor being not being changed.

5. the image forming apparatus further comprises a third detection unit for detecting a paper type of the sheet; 5. The post-processing device according to claim 1, wherein the control unit changes the first current value in accordance with the paper type detected by the third detection unit.

6. the image forming apparatus includes an input unit for inputting a paper type of a sheet; 5. The post-processing device according to claim 1, wherein the control unit changes the first current value in accordance with the paper type input by the input unit.

7. 7. The post-processing device according to claim 1, wherein the first motor is a stepping motor.

8. 8. The post-processing device according to claim 1, wherein the second motor is a stepping motor.

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