JP6677150B2 - Image forming device - Google Patents

Description

  The present invention relates to an image forming apparatus that performs post-processing of staples.

  The image forming apparatus may include a post-processing apparatus. The post-processing device performs post-processing on printed paper. The post-processing device is sometimes called a finisher. There are various types of post-processing. Patent Literature 1 describes an example of an apparatus that pierces a sheet and binds the hole with a ring member.

  Specifically, Japanese Patent Application Laid-Open No. H11-157572 discloses a method of performing a punching process on a sheet or a bundle of sheets, performing a process of binding the perforations with a ring member, and performing ring binding. Describes a bookbinding apparatus in which the interval between paper sets, which is the interval between the two, differs between the first mode in which the punching process and the binding process are performed and the second mode in which only the punching process is performed. With this configuration, the interval between paper sets is set in accordance with each mode, and an attempt is made to improve productivity when two modes are mixed (see Patent Document 1: Claim 1, paragraph [0008]).

JP 2009-262395 A

  In an image forming apparatus, a printing speed according to specifications may be determined. In such an image forming apparatus, paper feeding (paper feeding) is performed so as to satisfy a printing speed in specifications. For example, in the case of an image forming apparatus in which the number of prints per minute is 60, sheet feeding is started once per second. As described above, the sheet feeding start interval may be determined based on the specification. As a result, the printed paper is carried into the post-processing device at predetermined paper feed start intervals. Also, one sheet arrives at the processing tray in the post-processing apparatus at each sheet feeding start interval.

  When performing post-processing, each sheet is stacked on the processing tray in order while being aligned. Alignment is a process of aligning the edges of each sheet. When one sheet of paper is accumulated in the processing tray, the set post-processing is performed. The post-processed sheet bundle is discharged. A sheet bundle is discharged between the sets. After the stack has been ejected, the next set of sheets must reach the tray. Therefore, the paper feed start interval between sets is longer than the (normal) paper feed start interval other than between sets. For example, when performing post-processing, the time required for discharging the sheet bundle is added to the normal sheet feeding start interval. Therefore, when performing post-processing, the productivity (printing speed) of the image forming apparatus is reduced.

  Here, a staple unit may be mounted on the post-processing apparatus. The staple unit automatically binds the sheets when one set of sheets is accumulated in the tray. The stapled sheet bundle is discharged. When staple print jobs are continuously performed, stacking of one copy of paper → staple → discharge of paper bundle is repeated. It is also necessary to consider the time required for stapling. Note that the required time of staple is the time required from the start to the end of staple. When stapling is performed, the paper feed start interval between sets is equal to or longer than the normal paper feed start interval plus the time required for stapling and the time required for discharging the sheet bundle.

  Here, there is a variation in the required staple time for each staple unit. Further, the required time for staple varies depending on the thickness of the sheet bundle. The greater the number of sheets and the thicker the sheets, the longer the time from the start of stapling to the end of stapling. Therefore, the staple unit manufacturer sometimes determines the guaranteed time as a specification. The manufacturer guarantees that staples can be completed within the guaranteed time at the longest. The guaranteed time is the maximum time required for stapling. For example, the guaranteed time corresponds to the time required for stapling when the thickness of the sheet bundle is the maximum thickness that can be stapled.

  Conventionally, a paper feed start interval between sets has been determined based on the guaranteed time. That is, when stapling is performed, the paper feed start interval between sets is determined based on the time obtained by adding the normal paper feed start interval, the guaranteed time, the required time for bundle discharge, and the like. Thus, in any job, the first sheet of the next copy does not arrive before the sheet bundle is completely discharged. However, when stapling is performed, there is a problem that productivity (printing speed) of the image forming apparatus is likely to be reduced.

  The technique described in Patent Literature 1 does not mention reduction in productivity when stapling. The technique described in Patent Document 1 relates to perforation and ring binding. The post-processing targeted by Patent Literature 1 is not post-processing in which the required time varies depending on the number of sheets in a bundle and the type of paper, such as staples.

  According to the present invention, the interval between the start of sheet feeding between sets during stapling is made shorter than in the related art, and a decrease in productivity (printing speed) of the image forming apparatus is suppressed.

To solve the above problem, an image forming apparatus according to claim 1 includes a printing unit, a paper feeding unit, a print control unit, and a post-processing device. The printing unit prints on paper. The paper supply unit supplies paper to the printing unit. The printing control unit (engine control unit) controls the printing unit and the paper feeding unit. The post-processing device performs post-processing of a sheet printed by the printing unit. The post-processing device includes a sheet transport unit, a processing tray, an alignment discharge unit, a staple unit, and a detection sensor. The paper transport unit transports the paper printed by the printing unit. The paper transported by the paper transport unit is stacked on the processing tray. The alignment discharge unit aligns each sheet fed to the processing tray, and discharges the sheet after the post-processing. The stapling unit staples a sheet bundle on the processing tray. The detection sensor detects the arrival of the sheet in the processing tray and the ejection of the sheet to a discharge tray. At the time of staple continuous printing in which a plurality of copies are continuously printed by stapling each copy, the print control unit, except for the copy interval, when a predetermined sheet interval time has elapsed from the start of feeding of the immediately preceding sheet. Then, the paper feed unit is caused to start feeding the next paper. The print control unit determines whether the unit that has started feeding the sheet is a measurement target unit that measures a margin time. When the print control unit determines that the measurement target unit is determined, the print control unit determines that the reference inter-unit time has elapsed from the start of feeding of the last sheet of the measurement target unit (the interval between the measurement target unit and the next copy). In this case, the print control unit causes the paper feeding unit to start feeding the first sheet of paper next to the measurement target unit. The print control unit measures the time from when the detection sensor detects the discharge of the sheet bundle of the measurement target unit to when the first sheet of the next copy of the measurement target unit reaches the first sheet as the margin time. . Further, the print control unit determines the inter-correction unit time based on a value obtained by subtracting the margin time from the reference inter- unit time. When the inter-correction time has elapsed from the start of feeding of the last sheet of the non-measurement unit, the print control unit causes the sheet feeding unit to start feeding the first sheet of the next set. . The reference interval time is longer than the sheet interval time. The inter-correction unit time is shorter than the reference inter-unit time and is equal to or longer than a time obtained by subtracting the margin time from the reference inter-unit time.

  ADVANTAGE OF THE INVENTION According to this invention, the paper feeding start interval between the sets at the time of stapling can be made shorter than before. Thus, a decrease in productivity (printing speed) of the image forming apparatus can be suppressed.

FIG. 1 is a diagram illustrating an example of a multifunction peripheral according to an embodiment. FIG. 1 is a diagram illustrating an example of a multifunction peripheral according to an embodiment. FIG. 3 is a diagram illustrating an example of a sheet feeding unit according to the embodiment. It is a figure showing an example of the post-processing device concerning an embodiment. FIG. 4 is a diagram illustrating an example of a sheet feeding start interval and a copy time in the multifunction peripheral according to the embodiment. FIG. 4 is a diagram illustrating an example of a sheet feeding start interval and a copy time in the multifunction peripheral according to the embodiment. FIG. 6 is a diagram illustrating an example of a table for setting a time interval between sets according to the embodiment. FIG. 4 is a diagram illustrating an example of processing performed between copies in the multifunction peripheral according to the embodiment. FIG. 4 is a diagram illustrating an example of processing performed between copies in the multifunction peripheral according to the embodiment. It is a figure showing an example of a margin time. 6 is a flowchart illustrating an example of a flow of correcting a reference inter-unit time in the multifunction peripheral according to the embodiment.

  Hereinafter, an image forming apparatus according to the present invention will be described with reference to FIGS. The multifunction peripheral 100 will be described as an example of the image forming apparatus. However, each element of the configuration, arrangement, and the like described in the present embodiment does not limit the scope of the invention and is merely an example of description. In the following description, printing in which a plurality of copies are continuously printed and stapling is performed on each copy is referred to as “staple continuous printing”.

(Overview of image forming apparatus)
First, a multifunction peripheral 100 according to an embodiment will be described with reference to FIGS. FIGS. 1 and 2 are diagrams illustrating an example of the multifunction peripheral 100 according to the embodiment.

  The multifunction peripheral 100 includes a main control unit 1 and a storage unit 11. The main control unit 1 supervises the operation of the entire apparatus and controls each unit of the multifunction peripheral 100. The main control unit 1 includes a CPU 12 and an image processing unit 13. The CPU 12 performs calculations and controls related to control. The image processing unit 13 performs image processing necessary for a job on image data. The storage unit 11 includes a storage device such as a ROM, a RAM, and an HDD. The storage unit 11 stores a control program and data.

  The main control unit 1 is communicably connected to the document conveying unit 2a and the image reading unit 2b. The document transport unit 2a transports the set document toward the reading position. The image reading unit 2b reads a document conveyed by the document conveying unit 2a or a document set on a document table (contact glass, not shown). The image reading unit 2b generates image data of a document. The main control unit 1 controls the operations of the document conveying unit 2a and the image reading unit 2b.

  The main control unit 1 is communicably connected to the operation panel 3. The operation panel 3 includes a display panel 31, a touch panel 32, and hard keys 33. The operation panel 3 receives a user operation. The main control unit 1 recognizes the settings made on the operation panel 3. For example, when a predetermined operation is performed on the touch panel 32, the main control unit 1 causes the display panel 31 to display a setting screen related to the post-processing device 7. The setting screen includes a setting image. The setting image is a button or a key. Based on the operation of the setting image, the operation panel 3 accepts settings such as the presence or absence of post-processing in the post-processing device 7 and the presence or absence of staples.

  The multifunction peripheral 100 includes an engine control unit 4, a paper feeding unit 5, and a printing unit 6. The paper supply unit 5 supplies paper. Details of the paper feeding unit 5 will be described later. The printing unit 6 prints on paper. The printing unit 6 includes a transport unit 6a, an image forming unit 6b, and a fixing unit 6c. The engine control unit 4 (corresponding to a print control unit) is communicably connected to the main control unit 1. The main control unit 1 gives a print instruction, the contents of a print job, and image data used for printing to the engine control unit 4. Based on an instruction from the main control unit 1, the engine control unit 4 controls the operations of the sheet feeding unit 5 and the printing unit 6. Specifically, the engine control unit 4 causes the paper supply unit 5 to supply paper to the printing unit 6. The engine control unit 4 causes the transport unit 6a to transport the supplied sheet. The engine control unit 4 causes the image forming unit 6b to form a toner image. The image forming section 6b transfers the toner image to a sheet. The engine control unit 4 fixes the toner image transferred on the sheet to the fixing unit 6c.

  Further, the main control unit 1 includes a communication unit 14. The communication unit 14 is an interface for communicating with a computer 200 such as a PC or a server. The communication unit 14 receives data (print data) indicating print contents such as image data. The main control unit 1 causes the printing unit 6 to perform printing based on the printing data.

(Paper feed unit 5)
Next, an example of the sheet feeding unit 5 according to the embodiment will be described with reference to FIGS. FIG. 3 is a diagram illustrating an example of the sheet feeding unit 5 according to the embodiment.

  As shown in FIG. 2, the multifunction peripheral 100 includes, as the paper supply unit 5, a first paper supply cassette 51, a second paper supply cassette 52, and a registration roller pair 53. The first sheet cassette 51 and the second sheet cassette 52 store sheets. A first paper feed roller 54 is provided on the first paper feed cassette 51. The second paper feed roller 55 is provided on the second paper feed cassette 52. As shown in FIG. 3, a first paper feed motor 56 is provided to rotate the first paper supply roller 54. Further, a second paper feed motor 57 is provided to rotate the second paper feed roller 55.

  When printing is performed, the engine control unit 4 causes the first paper cassette 51 or the second paper cassette 52 to supply paper (primary paper feeding). When feeding paper from the first paper feed cassette 51, the engine control unit 4 rotates the first paper feed motor 56. The paper in the first paper cassette 51 is fed out by the first paper supply roller 54. When feeding paper from the second paper feed cassette 52, the engine control unit 4 rotates the second paper feed motor 57. The paper in the second paper feed cassette 52 is sent out by the second paper feed roller 55.

  The sheet sent from each sheet cassette is transported by the transport section 6a (transport roller pair 61). As a result, the sheet reaches the registration roller pair 53. The registration roller pair 53 is provided between each paper feed roller and the image forming unit 6b (see FIG. 2). As shown in FIG. 3, a registration motor 58 is provided to rotate the registration roller pair 53. The rotation of the registration motor 58 causes the registration roller pair 53 to rotate.

  The transport roller pair 61 and the registration roller pair 53 may be rotated by the same motor. In this case, an electromagnetic clutch (not shown) is provided for the pair of registration rollers 53. When rotating the registration roller pair 53, the engine control unit 4 connects the electromagnetic clutch. When stopping the pair of registration rollers 53, the engine control unit 4 releases the electromagnetic clutch.

  When the paper reaches the pair of registration rollers 53, the engine control unit 4 stops the pair of registration rollers 53. The leading edge of the paper strikes the nip of the pair of registration rollers 53. While abutting the leading end of the sheet against the pair of registration rollers 53, the engine control unit 4 continues the sheet conveyance. Due to the elasticity of the sheet, the leading end of the sheet follows the nip of the pair of registration rollers 53. Thereby, the skew of the sheet is corrected.

  After the skew correction, the engine control unit 4 rotates the registration roller pair 53. As a result, the sheet is supplied to the image forming unit 6b (secondary sheet feeding). The registration roller pair 53 functions as the paper supply unit 5 that supplies a sheet used for printing to the printing unit 6 (image forming unit 6b). Note that a registration sensor 59 is provided between the registration roller pair 53 and each paper feed roller. Based on the output of the registration sensor 59, the engine control unit 4 can recognize the arrival and passage of the sheet to the registration roller pair 53.

  In an image forming apparatus, a printing speed according to specifications may be determined. In the multifunction peripheral 100, the number of sheets that can be printed in one minute is determined. For example, the number of prints per unit time when using A4 paper is set to 60 sheets per minute (60 page per minute = 60 ppm). Further, since there is a specification of printing 30 sheets per minute, the ppm may be a value other than 60.

  The engine control unit 4 causes the paper to be fed so that the printing is performed at the printing speed according to the specification. Specifically, the engine control unit 4 causes the registration roller pair 53 to start feeding paper once every predetermined paper interval A1 (see FIGS. 5 and 6). The sheet interval A1 is a time obtained by dividing the unit time by the number of printed sheets according to the specification. The sheet interval A1 is predetermined according to the sheet size. When the A4 size is 60 ppm, the inter-sheet time A1 is 60 seconds / 60 sheets = 1 second.

  The engine control unit 4 stops the rotation of the registration roller pair 53 before the time A1 elapses from the start of rotation of the registration roller pair 53. The engine control unit 4 controls the printing speed by starting the rotation of the registration roller pair 53 at every sheet interval A1. The engine control unit 4 sends the first sheet cassette 51 (first sheet motor 56) and the second sheet cassette 52 (second sheet motor 57) in time for the second sheet feeding of the registration roller pair 53. Feed the paper.

  The engine control unit 4 starts rotation of the first paper feed roller 54 (first paper feed motor 56) and the second paper feed roller 55 (second paper feed motor 57) at every sheet interval A1. The printing speed may be controlled. In this case, the first paper cassette 51 and the second paper cassette 52 function as the paper supply unit 5 that supplies paper used for printing to the printing unit 6 (image forming unit 6b). Then, the engine control unit 4 starts the rotation of the registration roller pair 53 when a predetermined waiting time elapses after the output of the registration sensor 59 detects the arrival of the sheet.

(Post-processing device 7)
Next, an outline of the post-processing device 7 according to the embodiment will be described with reference to FIGS. FIG. 2 is a diagram illustrating an example of the MFP 100 to which the post-processing device 7 according to the embodiment is attached. FIG. 4 is a diagram illustrating an example of the post-processing device 7 according to the embodiment.

  The post-processing device 7 performs post-processing of the paper printed by the printing unit 6. The post-processing device 7 is attached to the main body of the multifunction peripheral 100. As shown in FIG. 2, the post-processing device 7 is attached (fitted) to the in-body discharge unit 101 of the multifunction peripheral 100. There is also an image forming apparatus of a type in which a post-processing device 7 is attached to the side of the device.

  The printed sheet that has passed through the fixing unit 6c is sent to the post-processing device 7 from the carry-in port 102. As shown in FIG. 2, the post-processing device 7 includes a punch unit 71, a sheet transport unit 72, a staple unit 8, a matching discharge unit 90, and a detection sensor 7s. The post-processing device 7 includes a processing tray 9 and a discharge tray 73.

  As shown in FIG. 4, the post-processing device 7 includes a post-processing control unit 70. The post-processing control unit 70 is a substrate including a processing circuit 70a such as a CPU, a memory 70b, and a clock circuit 70c. The post-processing control unit 70 controls the operation of each unit. Note that the post-processing control unit 70 may not be provided in the post-processing device 7, and the engine control unit 4 may control the operation of the post-processing device 7. When stapling is set on the operation panel 3, the post-processing control unit 70 causes the stapling unit 8 to perform stapling on the sheet bundle before discharge.

  When the setting for performing the punching process is made on the operation panel 3, the post-processing control unit 70 causes the punching unit 71 to perform the punching process on the sheet. When the setting for performing the punching process is not made on the operation panel 3, the post-processing control unit 70 does not cause the punching unit 71 to perform the punching process on the sheet.

  The paper transport unit 72 transports paper (printed paper) that has been carried in from the entrance 102 and passed through the punch unit 71. The paper transport unit 72 transports the paper to the processing tray 9. Paper is fed into the processing tray 9. As shown in FIG. 2, the paper transport section 72 includes a first transport roller pair 74, a second transport roller pair 75, and a paper transport guide 76. As shown in FIG. 4, the paper transport section 72 includes a transport motor 72m. When the paper is transported by the paper transport unit 72, the post-processing control unit 70 rotates the transport motor 72m. Thereby, the first transport roller pair 74 and the second transport roller pair 75 rotate.

  The post-processing control unit 70 causes the alignment discharge unit 90 to perform alignment of each sheet fed to the processing tray 9. Further, the post-processing control unit 70 causes the aligning and discharging unit 90 to discharge the sheet on which the post-processing has been completed. As shown in FIG. 2, the alignment discharge unit 90 includes a first discharge roller 91, a second discharge roller 92, and a width regulating plate 93. The first discharge roller 91 and the second discharge roller 92 are provided above the processing tray 9 on the downstream side in the transport direction. A second discharge roller 92 is provided at an end of the processing tray 9. The roller above the second discharge roller 92 is the first discharge roller 91. The first discharge roller 91 is supported by a roller holder 94. The first discharge roller 91 can swing vertically by the roller holder 94. The alignment discharge unit 90 includes a vertical movement mechanism 95 that moves the first discharge roller 91 and the roller holder 94 up and down. The vertical movement mechanism 95 may include a drive source. A motor or a solenoid can be used as the drive source.

  As shown in FIG. 4, the matching discharge unit 90 includes a discharge motor 9m. The discharge motor 9m is a motor that can rotate forward and backward. The first discharge roller 91 rotates according to the discharge motor 9m. In the following description, the direction in which paper is transported to the discharge tray 73 is referred to as a forward direction, and the direction in which paper is transported in a direction opposite to the discharge tray 73 is referred to as a reverse direction.

  The width regulating plate 93 is provided on the upper surface side of the processing tray 9. The width regulating plate 93 is a pair of plates. The sheet on the processing tray 9 is sandwiched in a direction perpendicular to the sheet transport direction. Then, the alignment discharge unit 90 includes a shift mechanism 96. The shift mechanism 96 moves the width regulating plate 93 in a direction perpendicular to the sheet conveyance direction. Shift mechanism 96 includes a motor. The shift mechanism 96 includes mechanical elements such as gears, belts, and shafts for moving the width regulating plate 93 in a direction perpendicular to the sheet conveyance direction. The post-processing control unit 70 causes the shift mechanism 96 to move the width regulating plate 93 in a direction perpendicular to the sheet conveyance direction. Thereby, the position of the end of each sheet on the processing tray 9 in the direction perpendicular to the sheet conveying direction can be aligned.

  A stopper 97 is provided at the upstream end of the processing tray 9 in the sheet transport direction. Further, a detection sensor 7s is provided downstream of the processing tray 9 (upstream of the discharge tray 73). The detection sensor 7s detects the arrival of the sheet in the processing tray 9 and the ejection of the sheet to the discharge tray 73.

  The staple unit 8 includes a staple driving source 81 and a staple mechanism 82. The staple driving source 81 is a solenoid or a motor. The stapling mechanism 82 includes a driver 83, a magazine 84, and a bending table 85. The staples are loaded into the magazine 84. The magazine 84 can be replenished with staples. The driver 83 is a metal plate that pushes down the staple. The bending table 85 is a table that bends the tip of the staple stuck through the paper inward. A magazine 84 is provided above the bending table 85. A driver 83 is provided above the magazine 84. A gap is provided between the bending table 85 and the magazine 84. The sheet bundle is located in this gap.

  When performing stapling, the post-processing control unit 70 operates the staple driving source 81. The driver 83 moves downward by the operation of the staple driving source 81. The driver 83 pushes down the first needle in the magazine 84. Thereby, the staples are driven into the paper. Further, the driver 83 pushes down the staple. The staples that have penetrated the paper are bent by the bending table 85. The binding of the paper is completed. At the same time, the position of the driver 83 returns to the original position.

  The operation panel 3 receives a setting of a stapling position. For example, the staple position can be set as in the upper right corner of the sheet bundle, in the middle of one side of the sheet. The post-processing control unit 70 causes the shift mechanism 96 to shift the position of the sheet bundle so that the staple is driven into the set position.

(1) When stapling When stapling, first, the post-processing control unit 70 causes the paper to be conveyed toward the discharge tray 73. The post-processing control unit 70 rotates the discharge motor 9m in the forward direction. The detection sensor 7s detects the arrival of the leading edge of the sheet. The output of the detection sensor 7s is input to the post-processing control unit 70. The post-processing control unit 70 recognizes that the paper has reached the installation position of the detection sensor 7s. When a predetermined time has elapsed from the detection of the arrival at the leading edge of the sheet, the post-processing control unit 70 moves the roller holder 94 and the first discharge roller 91 downward.

  Specifically, the post-processing control unit 70 controls the sheet and the first discharge roller at the timing when the trailing edge of the sheet passes through the sheet transport unit 72 (second transport roller pair 75) and the trailing edge of the sheet is placed on the processing tray 9. 91 is brought into contact. As a result, the uppermost sheet on the processing tray 9 contacts the first discharge roller 91. In this state, the post-processing control unit 70 rotates the discharge motor 9m in the reverse direction. Thus, the first discharge roller 91 rotates the sheet in the direction opposite to the discharge tray 73 (rotates in reverse). As a result, the upstream end of the uppermost sheet on the processing tray 9 abuts against the stopper 97. This makes it possible to align the ends of the sheet in the transport direction. Subsequently, the post-processing control unit 70 operates the shift mechanism 96 (width regulating plate 93). The alignment discharge unit 90 aligns the sheet in a direction perpendicular to the sheet transport direction.

  When one set of sheets is not accumulated in the processing tray 9, the post-processing control unit 70 repeats the upward retreat and the downward movement of the roller holder 94 and the first discharge roller 91. During the retreat upward, the leading edge of the next sheet passes between the first discharge roller 91 and the second discharge roller 92. The detection sensor 7s detects the arrival of the next leading edge of the sheet. Then, the next sheet is stacked on the processing tray 9. The post-processing control unit 70 repeats the sheet alignment each time the sheet arrives at the processing tray 9.

  When one set of sheets is accumulated in the processing tray 9, after the sheet alignment processing, the post-processing control unit 70 causes the stapling unit 8 to perform stapling processing before discharging the sheet bundle. After stapling, the post-processing control unit 70 causes the shift mechanism 96 to shift the position of the sheet bundle. For example, the post-processing control unit 70 shifts the position of the sheet bundle in a direction perpendicular to the sheet conveyance direction for each set. Thus, the position of the sheet bundle discharged to the discharge tray 73 is shifted by one copy.

  When discharging the sheet bundle, the post-processing control unit 70 lowers the roller holder 94 and the first discharge roller 91. The sheet comes in contact with the first discharge roller 91. After the shift of the sheet bundle, the post-processing control unit 70 rotates the discharge motor 9m forward. Thereby, the first discharge roller 91 and the second discharge roller 92 rotate in the sheet discharge direction (forward direction). As a result, the stapled sheet bundle is discharged to the discharge tray 73. Thereafter, in order to place the first sheet of the next set on the processing tray 9, the post-processing control unit 70 retracts the roller holder 94 and the first discharge roller 91 upward.

(2) In the case of ejecting one copy without stapling When stapling is not performed, the stapling process is skipped. Specifically, the post-processing control unit 70 causes the paper to be conveyed toward the discharge tray 73. The detection sensor 7s detects the arrival of the leading edge of the sheet. The post-processing control unit 70 recognizes that the paper has reached the installation position of the detection sensor 7s. Subsequently, the post-processing control unit 70 moves the roller holder 94 and the first discharge roller 91 downward.

  As a result, the first discharge roller 91 contacts the topmost sheet on the processing tray 9. In this state, the post-processing control unit 70 rotates the discharge motor 9m in the reverse direction. The post-processing control unit 70 aligns the ends of the sheet bundle in the transport direction. Subsequently, the post-processing control unit 70 operates the shift mechanism 96 (width regulating plate 93) to align the sheets.

  When one set of sheets is not accumulated in the processing tray 9, the post-processing control unit 70 repeats the upward retreat and the downward movement of the roller holder 94 and the first discharge roller 91. Further, the post-processing control unit 70 repeats the sheet alignment each time the sheet arrives at the processing tray 9.

  When one set of sheets is accumulated on the processing tray 9, after the sheet alignment process, the post-processing control unit 70 causes the shift mechanism 96 to shift the position of the sheet bundle. After shifting the sheet bundle, the post-processing control unit 70 rotates the discharge motor 9m forward. As a result, the sheet bundle is discharged to the discharge tray 73. Thereafter, the post-processing control unit 70 retracts the roller holder 94 and the first discharge roller 91 upward.

(3) In the case of discharging one sheet at a time without performing stapling The operation panel 3 can also be set to discharge one sheet at a time to the discharge tray 73. In this case, the post-processing control unit 70 maintains the roller holder 94 and the first discharge roller 91 at the lower position. Further, the post-processing control unit 70 rotates the discharge motor 9m forward. The paper is not stored in the processing tray 9. The sheets are discharged onto the discharge tray 73 one by one.

(Feeding start interval)
Next, an example of a sheet feeding start interval in the multifunction peripheral 100 according to the embodiment will be described with reference to FIGS. FIGS. 5 and 6 are diagrams illustrating an example of a sheet feeding start interval and an inter-unit time B1 in the multifunction peripheral 100 according to the embodiment.

  As described above, in the multifunction peripheral 100, paper feeding is basically started at every sheet interval A1. When the sheet feeding start interval is set to the sheet interval A1, the sheet is carried into the post-processing device 7 for each sheet interval A1. Also, based on the output of the detection sensor 7s, the post-processing control unit 70 recognizes the arrival of the sheet at every sheet interval A1. Further, sheets are stacked on the processing tray 9 at every sheet interval A1. The sheet alignment is performed after a sheet is stacked on the processing tray 9 and before the next sheet is stacked on the processing tray 9.

  Here, when stapling is performed by the post-processing device 7, processing of shifting the bundle of sheets for stapling, stapling, shifting for shifting the discharge position, and discharging the bundle is performed between the sets. Further, even when stapling is not performed, a shift for shifting the discharge position and a bundle discharge process are performed between the sets. When printing a plurality of sets continuously, it is necessary to perform these processes between sets. In other words, these processes need to be performed after the last sheet of the set is stacked on the processing tray 9 and before the sheet of the next set is stacked on the processing tray 9. Further, it is necessary to perform these processes between the sets from the time when the detection sensor 7s detects the arrival of the last sheet of the previous set to the time when the detection sensor 7s detects the arrival of the first sheet of the next set. is there. Therefore, between the sets, the sheet feeding start interval is longer than the sheet interval time A1.

  FIG. 5 shows an example of the sheet feeding start interval when the post-processing device 7 performs post-processing. FIG. 6 shows an example of a sheet feeding start interval when the post-processing device 7 does not perform post-processing. 5 and 6 show an example of a case where three copies are continuously printed. In FIGS. 5 and 6, the number of pages included in one copy is three.

  When printing a plurality of copies by performing post-processing, as shown in FIG. 5, between the copies, the engine control unit 4 sets the paper feed interval to the copy time B1. In other words, the time from the start of feeding the last sheet of the previous set to the feeding of the first sheet of the next set is defined as the inter-set time B1. Because of the process unique to the copy interval, the copy interval B1 is longer than the paper interval A1. In addition, for papers other than the last paper of the set, the engine control unit 4 sets the paper supply interval to the paper interval A1. The engine control unit 4 sets the sheet feeding interval from the first page of the set to the last two pages of the set as the sheet interval A1.

  When the sheet is discharged to the discharge tray 73 without post-processing (when the sheet is discharged as it is), the shift of the sheet bundle for stapling, the staple, the shift for shifting the discharge position, and the bundle discharge are performed between the sections. Not done. When the post-processing is not performed, as shown in FIG. 6, the engine control unit 4 sets the time from the start of feeding the last sheet of the previous set to the feeding of the first sheet of the next set as the sheet interval time. A1.

(Inter-unit time B1)
Next, an inter-unit time B1 in the multifunction peripheral 100 according to the embodiment will be described with reference to FIGS. FIG. 7 is a diagram illustrating an example of the inter-unit time setting table D1 according to the embodiment. FIG. 8 and FIG. 9 are diagrams illustrating an example of processing performed between units in the multifunction peripheral 100 according to the embodiment.

  When printing a plurality of copies by performing post-processing, the engine control unit 4 determines the inter-copy time B1 according to the content of the post-processing. In this description, a case where stapling is performed and a case where discharging is performed in bundles without performing stapling will be described.

  The storage unit 11 stores an inter-unit time setting table D1 for determining the inter-unit time B1. FIG. 7 shows an example of the inter-unit time setting table D1. In this table, processing performed between sets is defined. For example, sheet alignment, shift of a sheet bundle for stapling, staple, shift for shifting a discharge position, and bundle discharge are defined.

  The time required for each defined process is defined in the inter-unit time setting table D1. The required time T1 is the time required for aligning the sheets stacked on the processing tray 9. The required time T2 is a time required for shifting the sheet bundle in accordance with the stapling mechanism 82 (staple position). The required time T3 is the required time for staples. The required time T4 is a time required for a shift for shifting the discharge position. The required time T5 is the time required for discharging the bundle.

  The staple unit 8 has individual differences. When the same sheet and the same number of sheets are stapled, the required stapling time differs depending on the unit. Also, even for the same number of sheets, the thicker the sheet, the longer the required staple time. Further, even if the thickness of each sheet is the same, the required time for stapling becomes longer as the number of sheets increases. Therefore, the guaranteed time (longest time) in the specification of the staple unit 8 is adopted as the required time T3 of the inter-unit time setting table D1. The guaranteed time is a time guaranteed by the staple unit 8 manufacturer. Even when the thickness of the sheet bundle is the maximum thickness that can be stapled, stapling is completed within the guaranteed time from the start of stapling.

  As shown in FIG. 8, when stapling is performed, sheet alignment, shift of a sheet bundle for stapling, staple, shift for shifting a discharge position, and bundle discharge are performed between sets. Therefore, the engine control unit 4 sets a time obtained by adding the required times T1 to T5 to the inter-unit time B1. In the following description, when a plurality of copies are printed by stapling, the inter-copy time B1 determined by the engine control unit 4 based on the inter-copy time setting table D1 is referred to as a "reference inter-copy time B2". As shown in FIG. 8, the inter-unit time B1 (standard inter-unit time B2) when stapling is set to T1 + T2 + T3 + T4 + T5. The reference section time B2 may be a time obtained by adding a margin time to T1 + T2 + T3 + T4 + T5. Because of the processing unique to the post-processing (staple), the reference section time B2 is longer than the sheet time A1.

  FIG. 9 shows a case in which discharge is performed in bundles without performing stapling. In this case, staple processing is not performed. Sheet alignment, shift for shifting the discharge position, and bundle discharge are performed between the sets. Therefore, as shown in FIG. 9, the engine control unit 4 sets a time obtained by adding T1 + T4 + T5 to the inter-unit time B1. The inter-unit time B1 may be a time obtained by adding a margin time to T1 + T4 + T5.

(Correction of reference section time B2)
Next, an example of a flow of the correction of the reference unit time B2 according to the embodiment will be described with reference to FIGS. FIG. 10 is a diagram illustrating an example of the margin time T0. FIG. 11 is a flowchart illustrating an example of a flow of correcting the reference unit time B2 in the multifunction peripheral 100 according to the embodiment.

  As described above, when performing post-processing and printing a plurality of copies, the engine control unit 4 determines the inter-copy time B1. In the case of staple continuous printing, the engine control unit 4 determines the reference inter-unit time B2 as the inter-unit time B1. Staple continuous printing is printing in which a plurality of copies are continuously printed and stapling is performed on each copy. The guaranteed time is adopted as the required staple time T3 for setting the reference section time B2. Thus, the first sheet of the next copy is not stacked on the processing tray 9 before the sheet bundle is discharged. However, the longer the reference section time B2 is, the lower the productivity (printing speed) of the multifunction peripheral 100 is.

  The actual time required for staples is often shorter than the guaranteed time. The actual time required for stapling is not often the guaranteed time. Therefore, in many staple continuous printings, there is a margin from the completion of the bundle discharge to the detection of the arrival of the first sheet of the next copy.

  FIG. 10 shows an example in which the actual time required for stapling is shorter than the guaranteed time. In this case, there is a margin time T0 until the first page of the next copy is stacked on the processing tray 9. The multifunction peripheral 100 increases the productivity of the multifunction peripheral 100 by reducing or eliminating the allowance time T0.

  Thus, an example of a flow of correcting the reference inter-unit time B2 in the case of the staple continuous printing will be described with reference to FIG. The start in FIG. 11 is a point in time when the feeding of each unit of the staple continuous printing is started. In the continuous staple printing, the flowchart of FIG. 11 is executed each time one sheet feed is started.

  First, the engine control unit 4 confirms whether or not the sheet that has started feeding is the last two or more of the sets to be printed by staple continuous printing (step # 1). In the case of the last two or more copies, the staple continuous printing is completed in the next sheet to be fed or the sheet in which the sheet feeding is started. There is no unit that feeds paper at the corrected inter-unit time B1. Therefore, in the case of the second and subsequent copies (Yes in step # 1), this flow ends (END). Next, engine control unit 4 determines whether or not the unit that has started feeding is the measurement target unit (step # 2). The measurement target unit is a unit that measures the margin time T0.

  As a premise, one print job for printing a plurality of copies with staples corresponds to staple continuous printing. In addition, a case where a plurality of print jobs for printing one or a plurality of copies with staples are continuously performed also corresponds to staple continuous printing.

  The engine control unit 4 determines the first copy of the plurality of copies continuously printed by the staple continuous printing as the measurement target unit. In other words, the measurement target section is the first copy of a plurality of copies to be printed by staple continuous printing.

  When a plurality of print jobs are executed consecutively, the paper feed cassette may be changed between print jobs. In other words, there is a case where the sheet cassette used during the staple continuous printing is changed. In some cases, the thickness of the sheets stored in each sheet cassette is different. As a result, the spare time T0 may change. Therefore, the engine control unit 4 determines that the first copy printed after the change of the paper feed cassette is the measurement target copy.

  Further, when a plurality of print jobs are continuously executed, the number of copies of one copy may change between print jobs. In other words, the number of copies of one copy may change during staple continuous printing. When the number of copies of one copy changes, the thickness of the sheet bundle changes. For example, a print job of 25 copies per copy may be started next to a print job of 5 copies per copy. In this case, the allowance time T0 changes. Therefore, the engine control unit 4 determines that the first copy printed after changing the number of sheets is the measurement target copy.

  Further, in the case where the staple continuous printing is a printing in which a plurality of print jobs are continuously performed, the next print job is started during the staple continuous printing (the print job is switched). The engine control unit 4 determines whether the sheet cassette used in the immediately preceding print job and the newly started print job is the same, and whether the number of sheets included in one copy is the same. If both are determined to be the same, the engine control unit 4 does not treat the first copy of the newly started print job as the measurement target copy. If it is determined that any one of them is different, the engine control unit 4 treats the first copy of the newly started print job as the measurement target copy.

  When it is the measurement target section (Yes in step # 2), when the reference inter-unit time B2 has elapsed from the start of feeding the last sheet of the measurement target section, the engine control section 4 starts the next section next to the measurement target section. The sheet feeding unit 5 (registration roller pair 53) starts to feed the sheet (step # 3). Until all pages of one copy are stacked on the processing tray 9 (other than between copies), processing unique to the copy is not performed. For the sheets from the second page to the last page of one copy, the engine control unit 4 causes the registration roller pair 53 to feed the next sheet when the inter-paper time A1 has elapsed from the start of the feed of the immediately preceding sheet. To start.

  Then, based on the output of the detection sensor 7s, the post-processing control unit 70 measures the margin time T0 (step # 4). The timing circuit 70c of the post-processing control unit 70 may measure the allowance time T0. Specifically, the post-processing control unit 70 measures the time from when the detection sensor 7s detects the discharge of the measurement target unit to when the arrival of the first sheet of the next copy of the measurement target unit is detected (step # 4). The post-processing control unit 70 notifies the spare time T0 to the engine control unit 4. Based on this notification, engine control unit 4 recognizes spare time T0 (step # 5). Engine control section 4 determines correction section time B1 based on allowance time T0 (step # 6).

  Here, the engine control section 4 determines the correction section time B1 based on a value obtained by subtracting the allowance time T0 from the reference section time B2. The engine control unit 4 makes the inter-correction unit time B1 shorter than the reference inter-unit time B2. The engine control unit 4 may determine the value obtained by subtracting the allowance time T0 from the reference inter-unit time B2 as the inter-correction unit time B1. Further, the engine control unit 4 may determine a time obtained by adding a predetermined margin to a value obtained by subtracting the allowance time T0 from the reference inter-unit time B2, as the inter-correction unit time B1. In this case, the correction reference time is larger than a value obtained by subtracting the allowance time T0 from the reference inter-unit time B2.

  It may not be preferable that the inter-unit time B1 becomes too short. Therefore, when the time obtained by subtracting the allowance time T0 from the reference inter-unit time B2 is shorter than a predetermined minimum time, the print control unit may determine the minimum time as the correction inter-unit time B1. For example, a time obtained by adding the required times T1, T2, T4, and T5 to the shortest time required for staples specified in the specifications of the staple unit 8 may be used.

  If the unit that has started feeding is not the measurement target unit, the engine control unit 4 causes the paper to be fed at the correction unit time B1 between the units. That is, the engine control unit 4 starts feeding the first sheet of the next set to the registration roller pair 53 when the inter-correction unit time B1 has elapsed from the start of feeding of the last sheet of the set that is not the measurement target section. (Step # 7). Then, this flow ends (END)

  Conventionally, a paper feed start interval between sets has been determined based on the guaranteed time of the staple unit 8. The guaranteed time is the longest time for estimating the time required for staples. The actual time required for staples is often shorter than the guaranteed time. Therefore, the image forming apparatus according to the embodiment includes a printing unit 6, a paper feeding unit 5, a print control unit, and a post-processing device 7. The printing unit 6 prints on paper. The paper supply unit 5 supplies paper to the printing unit 6. The printing control unit (engine control unit 4) controls the printing unit 6 and the paper feeding unit 5. The post-processing device 7 performs post-processing of the paper printed by the printing unit 6. The post-processing device 7 includes a sheet transport unit 72, a processing tray 9, an alignment discharge unit 90, a staple unit 8, and a detection sensor 7s. The paper transport section 72 transports the paper printed by the printing section 6. The paper transported by the paper transport unit 72 is stacked on the processing tray 9. The aligning and discharging unit 90 aligns each sheet fed to the processing tray 9 and discharges the sheet after the post-processing. The stapling unit 8 staples a bundle of sheets on the processing tray 9. The detection sensor 7s detects the arrival of the sheet in the processing tray 9 and the ejection of the sheet to the discharge tray 73. In the case of staple continuous printing in which a plurality of copies are continuously printed by stapling each copy, the print control unit determines that a predetermined sheet interval time A1 has elapsed from the start of feeding of the immediately preceding sheet, except for between sets. Then, the paper feed unit 5 starts feeding the next paper. When the reference inter-set time B2 has elapsed from the start of feeding of the last sheet of the predetermined measurement target portion among the copies to be printed in the staple continuous printing (when the time between the measurement target portion and the next copy is set). ), The print control unit causes the sheet feeding unit 5 to start feeding the first sheet of the sheet next to the measurement target unit. The print control unit recognizes the allowance time T0 from when the detection sensor 7s detects the discharge of the sheet bundle of the measurement target unit to when it detects the arrival of the first sheet of the next copy of the measurement target unit. Further, the print control unit determines the inter-correction unit time B1 based on the allowance time T0. When the correction inter-unit time B1 has elapsed from the start of feeding of the last sheet of the non-measurement unit, the print control unit causes the sheet feeding unit 5 to start feeding the first sheet of the next set. The reference interval B2 is longer than the sheet interval A1. The inter-correction unit time B1 is shorter than the reference inter-unit time B2, and is equal to or longer than the time obtained by subtracting the allowance time T0 from the reference inter-unit time B2.

  As a result, it is possible to measure the margin time T0 from the completion of the discharge of the sheet bundle of the previous set to the arrival of the first sheet of the next set. Based on the allowance time T0, the paper feed start interval between the sets can be shortened. Therefore, the paper feed start interval between the sets during stapling can be made shorter than before. A decrease in productivity (printing speed) of the image forming apparatus can be suppressed.

  In addition, the allowance time T0 can be measured between the first copy and the second copy. The paper feed interval between the second and third sets can be set as the inter-correction section time B1. Strictly speaking, staple continuous printing is intended for continuous printing involving three or more staples.

  The measurement target portion is the first copy among the copies printed by the staple continuous printing. Thus, after the start of the job, the sheet feeding start interval between the second copy and the third copy and thereafter can be shortened. A decrease in productivity (printing speed) of the image forming apparatus can be suppressed.

  Further, the image forming apparatus includes a plurality of paper cassettes (first paper cassette 51 and second paper cassette 52). When the sheet cassette is switched, the thickness of the sheet bundle may change. When the thickness of the sheet bundle changes, the actual time required for stapling may change. In other words, the margin time T0 may change before and after the paper feed cassette is switched. Therefore, when the paper cassette to be used is changed during the staple continuous printing, the measurement target part is the first part to be printed after the paper cassette is changed. As a result, the inter-correction section time B1 can be reset, and the allowance time T0 can be measured again. Then, the appropriate inter-correction section time B1 can be reset.

  When the number of copies of one copy changes, the thickness of the sheet bundle may change. Due to the change in the thickness of the sheet, the actual time required for stapling may change. In other words, the margin time T0 may change before and after the number of sheets is changed. Therefore, when the number of sheets included in a set changes during the staple continuous printing, the measurement target section is the first set to be printed after the change in the number of sheets. As a result, the inter-correction section time B1 can be reset, and the allowance time T0 can be measured again. Then, the appropriate inter-correction section time B1 can be reset.

  Further, when the staple continuous printing is printing in which a plurality of print jobs are continuously performed, the print control unit determines that the same paper feed cassette is used in the print job in which a new paper feed is started and the immediately preceding print job. Then, it is determined whether or not the number of sheets included in one copy is the same. If both are determined to be the same, the print control unit does not treat the first copy of the newly started print job as the measurement target copy. In this case, in a print job in which paper feeding is newly started, when the correction inter-unit time B1 used in the immediately preceding print job has elapsed from the start of feeding of the last sheet in each unit, the engine control unit 4 sets the next. The sheet feeding unit 5 starts feeding the first sheet of the set. If it is determined that any one of them is different, the print control unit treats the first copy of the newly started print job as the measurement target copy. In this case, the spare time T0 and the inter-correction unit time B1 are set. Accordingly, when the contents of the print job (the number of sheets of the sheet source and the number of copies) are the same, the measurement of the margin time T0 in the subsequent print job can be skipped. Therefore, it is possible to suppress a decrease in productivity of the image forming apparatus as compared with a case where the margin time T0 is measured for each print job.

    If the gap between the last sheet of the previous set and the first sheet of the next set is too small, the sheets may easily collide or jam. Therefore, when the time obtained by subtracting the allowance time T0 from the reference inter-unit time B2 is shorter than the predetermined minimum time, the print control unit determines the minimum time as the inter-correction unit time B1. As a result, it is possible to secure a minimum required interval.

  The scope of the present invention is not limited to the description of the embodiments, and various modifications can be made without departing from the gist of the invention.

  The present invention is applicable to an image forming apparatus including a post-processing apparatus.

100 MFP (image forming apparatus) 4 Engine control unit (print control unit)
5 paper feed unit 51 1st paper feed cassette (paper feed cassette)
52 Second paper cassette (paper cassette)
53 Registration roller pair 6 Printing unit 7 Post-processing device 72 Paper transport unit 7s Detection sensor 8 Staple unit 9 Processing tray 90 Alignment discharge unit A1 Paper interval B2 Reference unit interval T0 Extra time

Claims (6)

A printing unit for printing on paper,
A paper supply unit for supplying paper to the printing unit,
A print control unit that controls the printing unit and the paper feeding unit;
A post-processing device that performs post-processing of the paper printed by the printing unit,
The post-processing device,
A paper transport unit that transports the paper printed by the printing unit,
A processing tray on which the paper transported by the paper transport unit is stacked,
An alignment discharge unit that aligns each sheet sent to the processing tray and discharges the sheet after the post-processing;
A staple unit that staples a sheet bundle of the processing tray;
A detection sensor for detecting the arrival of the paper to the processing tray and the discharge of the paper to the discharge tray,
At the time of staple continuous printing, which staples each part and prints multiple copies continuously,
The print control unit includes:
Other than between sets, when a predetermined time interval has elapsed from the start of feeding of the immediately preceding sheet, the sheet feeding unit is caused to start feeding the next sheet,
Judge whether the section that started feeding is the measurement target section that measures the margin time,
When it is determined that the sheet is the measurement target section, when the reference interval time has elapsed from the start of feeding of the last sheet of the measurement target section, the sheet feeding of the first sheet of the next section following the measurement target section is performed by the sheet feeding. Department to start,
The detection sensor measures the time from detecting the discharge of the sheet bundle of the measurement target unit to detecting the arrival of the first sheet of the next copy of the measurement target unit as the margin time,
Determine the correction unit time based on the value obtained by subtracting the margin time from the reference unit time ,
When the correction inter-unit time has elapsed from the start of feeding of the last sheet of the non-measurement unit, the feeding unit starts feeding of the first sheet of the next set,
The reference interval time is longer than the sheet interval time,
The image forming apparatus according to claim 1, wherein the inter-correction unit time is shorter than the reference inter-unit time, and is equal to or longer than a time obtained by subtracting the margin time from the reference inter-unit time.
  The image forming apparatus according to claim 1, wherein the measurement target unit is a first one of the units printed by the staple continuous printing. Including multiple paper cassettes,
When the paper cassette used during the staple continuous printing is changed,
The image forming apparatus according to claim 1, wherein the measurement target unit is a first unit to be printed after the sheet cassette is changed.   The method according to any one of claims 1 to 3, wherein when the number of sheets included in a set changes during the staple continuous printing, the measurement target section is the first set to be printed after the change in the number of sheets. The image forming apparatus as described in the above. Including multiple paper cassettes,
When the staple continuous printing is a printing in which a plurality of print jobs are continuously performed,
The print control unit determines whether the paper cassette to be used is the same and the number of sheets included in one copy is the same in the print job in which paper supply is newly started and the immediately preceding print job. And
When both are determined to be the same,
The print control unit does not treat the first copy of the print job that has newly started feeding as the measurement target unit,
When it is determined that either one is different,
5. The image forming apparatus according to claim 1, wherein the print control unit treats a first copy of the print job that has newly started feeding as the measurement target copy. 6. When the time obtained by subtracting the margin time from the reference inter-unit time is shorter than a predetermined minimum time,
The image forming apparatus according to claim 1, wherein the print control unit determines the minimum time as the inter-correction-unit time.

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