JP4574474B2 - Paper post-processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that processes a sheet after image formation, and an image forming apparatus such as a copying machine, a printer, a facsimile, a plotter, a printing machine, and a multifunction peripheral having the same.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, a printing machine, or a multi-function machine, a technique for folding and feeding paper after image formation into a Z-shape when viewed from the side is disclosed in, for example, “Patent Document 1”. ing. According to this technology, by turning back a sheet on which an image has been formed into a Z-shape when viewed from the side (hereinafter referred to as a Z-folding process), for example, an A3 size sheet can be changed to an A4 size. Different sheets can be neatly aligned on the discharge tray.

Japanese Patent Laid-Open No. 1-133867

  In the technique disclosed in “Patent Document 1”, when performing the Z-folding process, the sheet passes through a sheet conveying path dedicated to the Z-folding process that is longer than the sheet conveying path when the Z-folding process is not performed. For this reason, when a sheet post-processing operation is performed by mixing a sheet that performs the Z-folding process and a sheet that does not perform the Z-folding process, a sheet that does not perform the Z-folding process is the next sheet that does the Z-folding process. When transported, the sheet transported later must wait for the transport of the previously transported sheet until the Z-folding process is completed, resulting in a decrease in productivity.

  The present invention solves the above-described problems, and can perform a sheet post-processing operation by mixing a sheet that performs Z-folding processing and a sheet that does not perform Z-folding processing without reducing productivity. An object is to provide an apparatus and an image forming apparatus including the apparatus.

The invention according to claim 1 is connected to the image forming apparatus main body, accepts the paper discharged from the image forming apparatus main body, and discharges the paper after performing Z-folding processing on the paper by the Z-folding means. In the sheet post-processing apparatus, the Z-folding unit includes a first roller pair for transporting a processing sheet for performing Z-folding processing to a first processing transport path, and a first roller for stopping the leading end of the processing sheet. The first stop member movably disposed in the processing transport path, and the processing paper whose leading end is stopped by the first stop member are further transported by the first roller pair. A second roller pair that forms a first fold on the processing sheet with a bend and conveys it to the second processing conveyance path, and can move to the second processing conveyance path to stop the tip of the first fold. 2nd stop member arranged in A second crease is formed on the processing sheet by sandwiching a bend formed when the processing sheet whose leading end is stopped by the second stopping member is further conveyed by the second roller pair. A third roller pair transported to the paper discharge transport path, a first position for guiding the processed paper that has passed through the first roller pair to the first process transport path, and Z that has passed through the first roller pair. A first guide member that selectively occupies a second position for guiding the non-processed paper not to be folded to the second roller pair, and the processed paper that has passed through the second roller pair is subjected to a second process. A second guide member that selectively occupies the first position for guiding the conveyance path and the second position for guiding the non-processed paper that has passed through the second roller pair to the third roller pair; The processing paper and the non-processing paper are continuously conveyed to the Z-folding means. In this case, the processing sheet is transported after positioning the first guide member and the second guide member at the first position and passing through the first processing transport path and the second processing transport path, respectively. The non-processing paper is conveyed without passing through the first processing conveyance path and the second processing conveyance path by positioning the first guide member and the second guide member at the second position, respectively. The sheet conveyance speed is made faster than the sheet conveyance speed of the non-processed sheet .

  According to a second aspect of the present invention, in the paper post-processing apparatus according to the first aspect, an inlet-side transport unit that transports the processed paper and the non-processed paper toward the Z-folding unit and the Z-folding unit. Exit-side transport means for transporting the processed paper and the non-processed paper to be discharged, and the paper transport speed of the Z-folding means and each of the transport means when transporting the processed paper is determined as the non-process paper. It is characterized in that it is earlier than the time of transportation.

According to a third aspect of the present invention, in the paper post-processing apparatus according to the second aspect , the first roller pair further includes a driving roller that is rotationally driven and a first driven roller that is disposed in pressure contact with the first driven roller and is driven to rotate. The second roller pair is composed of the drive roller and a second driven roller which is arranged in pressure contact with the drive roller and can be driven to rotate. The third roller pair is arranged in pressure contact with the second driven roller and driven rotated. And a third driven roller capable of changing the rotational peripheral speed of the driving roller, and the driven roller is driven to rotate as the driving roller rotates .

According to a fourth aspect of the invention, in the paper post-processing apparatus according to the third aspect of the invention, the paper post-processing apparatus further includes a paper leading edge detecting means disposed immediately upstream of the first roller pair in the paper conveying direction. The drive roller is rotationally driven at a predetermined timing after being detected by the paper leading edge detection means .

According to a fifth aspect of the present invention, in the paper post-processing apparatus according to any one of the second to fourth aspects, the inlet-side transport unit further moves the paper discharged from the image forming apparatus main body to the downstream side. A pair of entrance rollers for transporting and a pair of transport rollers for transporting a sheet fed from the pair of entrance rollers to the Z-folding means, and the pair of entrance rollers and the pair of transport rollers are rotated by different drive means. It is driven, and each rotational peripheral speed can be changed independently of each other .

According to a sixth aspect of the present invention, in the paper post-processing apparatus according to the fifth aspect , the pair of inlet rollers further has a connecting / disconnecting means, and the leading edge of the paper discharged from the image forming apparatus main body is the inlet roller. Rotation driving force from the driving means is cut off when the conveying roller pair disposed at the position immediately downstream of the pair is inserted, and can be driven to rotate as the sheet conveyed by the conveying roller pair moves. It is configured .

A seventh aspect of the present invention is an image forming apparatus having the paper post-processing apparatus according to any one of the first to sixth aspects .

  According to the present invention, it is possible to make the time required for the processed paper that performs the Z-folding process and the non-processed paper that does not perform the Z-folding process to pass through the inside of the paper post-processing apparatus, thereby preventing a decrease in productivity. can do.

  FIG. 1 is a schematic front view of an image forming apparatus employing an embodiment of the present invention. In FIG. 1, an image forming apparatus 1 is configured by integrally connecting an electrophotographic copying apparatus 2 as a main body of an image forming apparatus and a sheet post-processing apparatus 3. The electrophotographic copying apparatus 2 has a well-known configuration including a photosensitive drum, a developing device, an image reading device, an exposure device, a transfer device, a fixing device, a paper feeding device, a paper discharging device, and the like on its right side. A paper feed tray 2a for stacking paper is provided. On the left side of the electrophotographic copying apparatus 2, there is disposed a discharge port 2b for discharging a sheet on which an image has been formed. Further, on the left side, a sheet post-processing apparatus 3 is integrally connected by a connecting member (not shown). ing.

  The sheet post-processing apparatus 3 has a sheet receiving port 3a on the right side and a sheet discharging port 3b on the left side, and the electrophotographic copying apparatus with the sheet receiving port 3a communicating with the discharging port 2b. 2 is connected. On the left side of the sheet discharge port 3b, a sheet discharge tray 3c for stacking sheets on which images have been formed is disposed so as to freely move up and down.

  As shown in FIG. 2, the sheet post-processing device 3 has a sheet conveyance path 4 connecting the sheet reception port 3 a and the sheet discharge port 3 b inside thereof, and is disposed on the sheet reception path 3 a side of the sheet conveyance path 4. A pair of inlet rollers 5 and an inlet sensor 6 are disposed on the side of the sheet discharge path 3b of the sheet conveying path 4, and a pair of sheet discharge rollers 7 and an outlet sensor 8 are disposed.

  The inlet roller pair 5 is composed of a driving roller that is rotationally driven by a variable speed type stepping motor 42 (see FIG. 3) and a driven roller that is disposed in pressure contact with the driving roller. Based on this, the stepping motor 42 is driven to rotate. The drive roller is provided with an electromagnetic clutch (not shown) as connecting / disconnecting means. When the drive roller receives external force and rotates, the rotational force of the drive roller acts on the stepping motor 42 by the operation of the electromagnetic clutch (not shown). It is configured not to. The inlet sensor 6 outputs a signal to the control means 41 when detecting the leading edge of the paper sent from the paper receiving port 3a.

  The paper discharge roller pair 7 includes a driving roller that is rotationally driven by a variable speed motor (not shown) and a driven roller that is pressed against the driving roller. The motor is operated based on an operation command from the control means 41. It is rotationally driven by this. The exit sensor 8 outputs a signal to the control means 41 when detecting the trailing edge of the paper discharged from the paper discharge port 3b.

  In the middle of the paper transport path 4, a first position indicated by a two-dot chain line in FIG. 2 guides the paper received from the paper receiving port 3a directly to the paper discharge port 3b via the paper transport path 4. A second position indicated by a solid line in FIG. 2 guides a sheet received from the sheet receiving port 3a to a sheet discharge port 3b via an inlet side conveying unit 9, a Z folding unit 22 and an outlet side conveying unit 10 which will be described later. A guide guide plate 33 that selectively occupies is disposed. The guide guide plate 33 selectively occupies the first position and the second position by the operation of the solenoid 43 (see FIG. 3), and the operation of the solenoid 43 is controlled by the control means 41.

  An entrance-side transport unit 9 is disposed below the right side of the sheet transport path 4, and an exit-side transport unit 10 is disposed below the left side of the sheet transport path 4. The entrance-side transport unit 9 includes the above-described entrance roller pair 5 and the respective transport roller pairs 11, 12, 13, and 14. The exit-side transport unit 10 includes the above-described paper distribution roller pair 7 and the respective transport roller pairs 15, 16 and 17. A plurality of guide plates are disposed between each pair of rollers constituting the entrance-side transport unit 9 and the exit-side transport unit, and an entrance-side sheet transport path 18 and an exit-side sheet transport path 19 as a sheet discharge transport path. Are formed respectively. A first sensor 20 for detecting the leading edge of the sheet is detected at a portion positioned between the pair of conveying rollers 13 and 14 in the inlet-side sheet conveying path 18, and a leading edge of the sheet is detected at the end position of the inlet-side sheet conveying path 18. A second sensor 21 is disposed as a sheet leading edge detection unit. Each of the conveying roller pairs 11, 12, 13, 14, 15, 16, and 17 is composed of a driving roller and a driven roller pressed against the driving roller, and each driving roller is rotationally driven by a speed variable motor (not shown). Thus, it is driven to rotate at the set rotational peripheral speed. Each sensor 20, 21 outputs a signal to the control means 41 when it detects the leading edge of the paper.

  A Z-folding unit 22 is disposed at a position between the entrance-side transport unit 9 and the exit-side transport unit 10 in the sheet transport direction. The Z-folding means 22 includes a driving roller 23, a driven roller 24 that is a first driven roller, a driven roller 25 that is a second driven roller, a driven roller 26 that is a third driven roller, and a first processing conveyance path 27. The first paper leading end stopper 28 serving as the first stopping member, the second processing conveyance path 29, the second paper leading end stopper 30 serving as the second stopping member, and the first swing guide 31 serving as the first guiding member. And a second swinging guide 32 that is a second guide member.

  The drive roller 23 is rotatably supported by the apparatus main body, and is driven to rotate by a variable speed brushless motor 44 (see FIG. 3). The driven roller 24 and the driven roller 25 are rotatably supported by the main body of the apparatus in such a manner that the driven roller 24 and the driven roller 25 are in pressure contact with the drive roller 23 and the driven roller 26 is in pressure contact with the driven roller 25. Rotate. The first roller pair 34 is composed of the driving roller 23 and the driven roller 24, the second roller pair 35 is composed of the driving roller 23 and the driven roller 25, and the third roller pair 36 is composed of the driven roller 25 and the driven roller 26. Each is composed.

  Above the first roller pair 34, a first processing conveyance path 27 for Z-folding the sheet by a plurality of guide plates is formed, and the leading edge of the sheet is in the first processing conveyance path 27. A first paper leading end stopper 28 is disposed to abut. The first paper leading end stopper 28 is configured to be movable in the first processing conveyance path 27 by a stepping motor (not shown), and is arbitrarily set between a home position indicated by a solid line and a position indicated by a two-dot chain line in FIG. Occupy position. The position of the first paper front end stopper 28 is changed according to the size of the paper or the Z-folding method, and is determined based on a command from the control means 41. In the vicinity of the first processing conveyance path 27, a home position sensor 37 is provided for detecting when the first paper leading end stopper 28 occupies the home position.

  Below the second roller pair 35, a second processing conveyance path 29 for Z-folding the sheet by a plurality of guide plates is formed, and the leading edge of the sheet is in the second processing conveyance path 29. A second paper leading end stopper 30 is provided in contact therewith. The second paper leading end stopper 30 is configured to be movable in the second processing conveyance path 29 by a stepping motor (not shown), and is arbitrarily set between a home position indicated by a solid line and a position indicated by a two-dot chain line in FIG. Occupy position. The position of the second paper leading edge stopper 30 is changed depending on the paper size or the Z-folding method, and is determined based on a command from the control means 41. In the vicinity of the second processing conveyance path 29, a home position sensor 38 is provided for detecting when the second paper leading end stopper 30 occupies the home position.

  A first swing guide 31 that is swingably supported on the apparatus main body by a support shaft 31a is disposed on the upper right side of the driven roller 24. The first swing guide 31 has an arm shape having an arc-shaped tip, and is swung by a swinging means (not shown) such as a stepping motor or a solenoid, so that the tip is a first processing conveyance path. The first position shown by a solid line in FIG. 2 that deviates from 27 and the second position shown by a two-dot chain line in FIG. 2 where the first processing conveyance path 27 is closed by the tip portion thereof are selectively occupied. In the vicinity of the first swing guide 31 occupying the first position, a guide detection sensor 39 is provided for detecting when the first swing guide 31 occupies the first position.

  Below the driving roller 23, a second swinging guide 32 is provided that is swingably supported by the apparatus main body by a support shaft 32a. The second swing guide 32 also has an arm shape having an arc-shaped tip, and is swung by a swinging means (not shown) such as a stepping motor or a solenoid, so that the tip is a second processing conveyance path. 2 that is out of 29 is selectively occupied by the first position indicated by the solid line in FIG. 2 and the second position indicated by the two-dot chain line in FIG. In the vicinity of the second swing guide 32 that occupies the first position, a guide detection sensor 40 that detects when the second swing guide 32 occupies the first position is disposed.

  FIG. 3 is a block diagram of the control means 41 of the paper post-processing apparatus 3. The control means 41 including a CPU 45, a clock 46, a driver 47, a motor driver 48, a driver 49, a ROM and a RAM (not shown), and the like, includes a detection signal from various sensors and a control means 50 of the image forming apparatus 1. In response to these various signals, operation control of various actuators such as a stepping motor 42, a solenoid 43, a brushless motor 44, and a stepping motor (not shown) is performed.

  Based on the above configuration, the operation of the sheet post-processing apparatus 3 will be described below. In this embodiment, by operating an operation panel (not shown) provided in the electrophotographic copying apparatus 2, the first mode in which Z folding processing is not performed by the sheet post-processing apparatus 3 on all sheets, Either a second mode in which Z-folding processing is performed by the paper post-processing device 3 or a third mode in which Z-folding processing is performed by the paper post-processing device 3 for only a part of paper can be selected.

  First, the operation when the first mode is selected will be described. When the first mode is selected, a command is sent from the control means 41 to the solenoid 43, and the guide guide plate 33 occupies the first position. Then, the sheet discharged from the discharge port 2b of the electrophotographic copying apparatus 2 is sent to the inside of the sheet post-processing device 3 from the sheet receiving port 3a, and when the leading edge of the sheet is detected by the inlet sensor 6, the sheet is discharged from the inlet sensor 6. A signal is sent to the control means 41. Upon receiving the signal, the control means 41 operates the stepping motor 42 to rotate and drive the inlet roller pair 5, and operates a speed variable motor (not shown) to discharge the paper discharge roller pair 7. Are rotated at the same peripheral speed as the inlet roller pair 5. As a result, the sheet sent from the sheet receiving port 3a to the inside of the sheet post-processing device 3 is sent out from the sheet discharge port 3b through the sheet transport path 4 and stacked on the sheet discharge tray 3c.

  Next, the operation when the second mode is selected will be described. When the second mode is selected, a command is sent from the control means 41 to the solenoid 43, and the guide guide plate 33 occupies the second position. Thereafter, the first paper leading edge stopper 28 and the second paper leading edge stopper 30 are positioned at predetermined positions, respectively. This positioning operation will be described with reference to the flowchart shown in FIG.

  When the second mode is selected in the image forming apparatus 1 and this command is received by the control means 41 (ST1), the control means 41 confirms the signal from the home position sensor 37 (ST2) and the leading edge of the first sheet It is determined whether or not the stopper 28 is located at the home position. If the first paper leading end stopper 28 is not located at the home position, the control means 41 drives a stepping motor (not shown) in reverse (ST3). Next, the control means 41 confirms the signal from the home position sensor 38 (ST4) and determines whether or not the second paper leading edge stopper 30 is located at the home position. If the second paper leading end stopper 30 is not located at the home position, the control means 41 drives a stepping motor (not shown) in reverse (ST5).

  Then, the control means 41 confirms again the signal from the home position sensor 37 (ST6), and if the home position sensor 37 is turned on and it is determined that the first paper leading edge stopper 28 is located at the home position, the first paper is detected. The operation of a stepping motor (not shown) that moves the tip stopper 28 is stopped (ST7). When the home position sensor 37 is not turned on, the operation of a stepping motor (not shown) is continued.

  Next, the control means 41 confirms the signal from the home position sensor 38 again (ST8), and if the home position sensor 38 is turned on and it is determined that the second paper leading edge stopper 30 is located at the home position, the second control unit 41 The operation of a stepping motor (not shown) that moves the paper leading end stopper 30 is stopped (ST9). When the home position sensor 38 is not turned on, the operation of a stepping motor (not shown) is continued.

  Then, when the first sheet leading edge stopper 28 and the second sheet leading edge stopper 30 are positioned at the home position and signals are sent from the respective home position sensors 37 and 38 (ST10), they are detected on the electrophotographic copying apparatus 2 side. Based on the paper size and the method of folding the paper set on the electrophotographic copying apparatus 2 side, the control means 41 sends an operation command to each stepping motor and drives each stepping motor to rotate forward, thereby causing the first paper leading edge stopper 28 and The second paper leading end stopper 30 is moved to a predetermined position (ST11, ST12). When the first paper leading edge stopper 28 and the second paper leading edge stopper 30 are positioned at predetermined positions and it is confirmed by the control means 41 that the operation of each stepping motor has been stopped (ST13), the first paper leading edge stopper 28 is detected. And the positioning operation of the second paper leading end stopper 30 is completed.

  When the guide guide plate 33 occupies the second position and the positioning operation of the first paper front end stopper 28 and the second paper front end stopper 30 is completed, the control means 41 confirms signals from the respective guide detection sensors 39 and 40. When it is determined that the signals from the guide detection sensors 39 and 40 are not sent and the first swing guide 31 and the second swing guide 32 occupy the second position, The control means 41 sends an operation command to a rocking means (not shown) that rocks the rocking guides 31 and 32 to position the rocking guides 31 and 32 at the first positions.

  The operation of the sheet post-processing apparatus 3 performed following the above-described operation will be described based on the flowchart shown in FIG. When the guide guide plate 33 occupies the second position, the positioning operation of the first paper front end stopper 28 and the second paper front end stopper 30 is completed, and the swing guides 31 and 32 occupy the first position, respectively. The sheet discharged from the discharge port 2b of the electrophotographic copying apparatus 2 is sent into the sheet post-processing device 3 from the sheet receiving port 3a, and the leading edge of the sheet is detected by the inlet sensor 6 (ST21). To the control means 41. Upon receipt of the signal, the control means 41 operates a stepping motor 42, two variable speed motors (not shown), respectively, to enter the inlet roller pair 5, the discharge roller pair 7, and the transport roller pairs 11, 12, 13, 14,. 15, 16, and 17 are all driven to rotate at the same rotational peripheral speed (ST22).

  The sheet sent from the sheet receiving port 3a to the inside of the sheet post-processing device 3 is conveyed by the pair of inlet rollers 5 and guided to the inlet side sheet conveying path 18 by the guide guide plate 33 occupying the second position. The sheet sent to the inlet side sheet conveyance path 18 is conveyed by each of the conveyance roller pairs 11, 12, 13, and 14, and the leading end thereof is detected by the second sensor 21 (ST23). Upon receiving the detection signal from the second sensor 21, the control means 41 excites the stepping motors that drive the first paper leading edge stopper 28 and the second paper leading edge stopper 30, and causes the leading edge of the paper to move to the first roller pair 34. Each of the conveying roller pairs 11, 12, 13, and 14 is rotationally driven for a predetermined time while being in contact with the nip portion, thereby preventing the positional deviation of the paper leading end stoppers 28 and 30 when the paper leading end is in contact with the paper. Skew correction is performed (ST24).

  After a predetermined time elapses, the control means 41 sends an operation command to the brushless motor 44, whereby the drive roller 23 is driven to rotate and each driven roller 24, 25, 26 starts driven rotation. The sheet whose tip is in contact with the nip portion of the first roller pair 34 is conveyed upward by the rotation of the rollers 23 and 24, and the first swing guide 31 occupies the first position. To the first processing conveyance path 27, and the leading edge thereof is brought into contact with the first sheet leading edge stopper 28 (see FIG. 7A).

  Even after the leading edge abuts against the first sheet leading edge stopper 28, the sheet is fed by the conveyance roller pairs 11, 12, 13, 14 and the rollers 23, 24 at the subsequent portion thereof. Deflection is formed in the space between the inlet and each of the rollers 23 and 24 (see FIG. 7B). The formed deflection is held by the second roller pair 35, and a first folded portion is formed as shown in FIG. 6A (see FIG. 7C).

  The sheet in which the first folding part is held by the second roller pair 35 is sent to the second processing conveyance path 29 at the tip of the first folding part. At this time, the leading end portion of the paper stored in the first processing conveyance path 27 is pulled out (see FIG. 7D), and after the paper passes through the first roller pair 34, the circumference of the drive roller 23 is increased. After passing through the second roller pair 35 in a shape along the surface, the front end of the first folding portion is brought into contact with the second paper front end stopper 30 in due course.

  Even after the leading end of the first folding portion comes into contact with the second sheet leading end stopper 30, the sheet is fed by the conveying roller pairs 11, 12, 13, 14 and the rollers 23, 24, 25 to the second portion. Deflection is formed in the space between the inlet of the processing conveyance path 29 and the rollers 23 and 25 (see FIG. 7E). The formed deflection is held by the third roller pair 36 together with the leading edge of the sheet, and a second folded portion is formed as shown in FIG. 6B (see FIG. 7F).

  After the leading edge and the second fold are held by the third roller pair 36, the sheet is fed into the exit side sheet conveying path 19 and conveyed upward by the conveying roller pairs 15, 16, and 17. It is sent to the paper transport path 4. The paper sent to the paper transport path 4 is detected by the exit sensor 8 when it is discharged to the outside by the paper discharge roller pair 7 (ST25), and a detection signal is sent to the control means 41. When the trailing edge of the paper finishes passing through the exit sensor 8, the detection signal sent from the exit sensor 8 is turned off. Thereafter, the same process as described above is repeated until the final paper is reached, and the trailing edge of the final paper passes through the outlet sensor 8 and the detection signal sent from the outlet sensor 8 to the control means 41 is turned off. (ST26), a stop command is sent from the control means 41 to each actuator (ST27), and the sheet post-processing device 3 enters a standby state. The Z-folded paper is stacked on the paper discharge tray 3c.

  Next, the operation when the third mode is selected will be described. In this third mode, only a part of the sheets is subjected to the Z-folding process by the sheet post-processing device 3, which of the sheets is subjected to the Z-folding process is set in advance on the electrophotographic copying apparatus 2 side. When the third mode is selected, a command is sent from the control means 41 to the solenoid 43 so that the guide guide plate 33 occupies the second position, and the first paper leading end stopper 28 is used as in the second mode selection. The second paper leading end stopper 30 is positioned at a predetermined position. In the third mode, a sheet on which the Z-folding process is performed is a processing sheet, and a sheet on which the Z-folding process is not performed is a non-processing sheet.

  The operation of the sheet post-processing apparatus 3 performed following the above-described operation will be described based on the flowcharts shown in FIGS. When the guide guide plate 33 occupies the second position and the positioning operation of the first sheet leading end stopper 28 and the second sheet leading end stopper 30 is completed, the sheet discharged from the discharge port 2b of the electrophotographic copying apparatus 2 is received by the sheet receiving unit. A signal is sent from the inlet 3a to the inside of the paper post-processing apparatus 3 and the leading edge of the paper is detected by the inlet sensor 6 (ST31). Upon receipt of the signal, the control means 41 operates a stepping motor 42, two variable speed motors (not shown), respectively, to enter the inlet roller pair 5, the discharge roller pair 7, and the respective transport roller pairs 11, 12, 13, 14, 15 , 16 and 17 are all driven to rotate at the same rotational peripheral speed (800 mm / sec in this embodiment) (ST32).

  Then, when the control means 41 determines that the leading edge of the paper has been caught in the nip portion of the conveying roller pair 11 based on the number of steps of the stepping motor 42 (ST33), a command is sent from the control means 41 to activate an electromagnetic clutch (not shown). The inlet roller pair 5 rotates following the movement of the sheet conveyed by the conveying roller pair 11. This driven rotation is continued until the next sheet is detected by the entrance sensor 6.

  Simultaneously with the operation of the electromagnetic clutch (not shown), the control means 41 analyzes the signal from the control means 50 to determine whether or not this sheet is to be subjected to the Z-folding process (ST34). If it is determined that the Z-folding process is to be performed, the control means 41 sends commands to two variable speed motors (not shown), and the paper discharge roller pair 7 and the transport roller pairs 11, 12, 13, 14, 15 , 16 and 17 are increased to 1200 mm / sec (ST35). If it is determined not to perform the Z-folding process, the control means 41 does not change the rotational peripheral speeds of the paper discharge roller pair 7 and the transport roller pairs 11, 12, 13, 14, 15, 16, and 17 (ST36). ).

  In this embodiment, the rotational peripheral speeds of the paper discharge roller pair 7 and the transport roller pairs 11, 12, 13, 14, 15, 16, and 17 at the time of speed increase are set to 1200 mm / sec. A processing sheet on which the Z-folding process is performed is transported from the sheet receiving port 3 a to the inside of the sheet post-processing device 3, and thereafter includes an inlet-side transport unit 9, a first processing transport path 27, and a second processing transport path 29. The time until the paper is discharged from the paper discharge port 3b through the Z-folding means 22, the outlet-side transport means 10, and the paper transport path 4, and the unprocessed paper that is not subjected to the Z-folding process is fed from the paper inlet 3a. The Z-folding means 22 that does not include the entrance-side transport means 9, the first processing transport path 27, and the second processing transport path 29, the exit-side transport means 10, and the paper transport. Paper exit 3 via path 4 Time until discharged from is set to be substantially the same.

  When the first sensor 20 detects the leading edge of the paper transported by each of the transport roller pairs 11, 12, 13 (ST37), the control means 41 that has received the detection signal determines whether the paper is to be subjected to Z-folding processing. (ST38), and if it is determined that the sheet is a processing sheet for performing Z-folding processing, the respective guide detection sensors 39, 40 are turned on, and the first swing guide 31 and the second swing guide 32 are respectively set to the first. Is determined (ST39). If the first position is not occupied, an operation command is sent to a swing means (not shown) (ST40), and the swing guides 31 and 32 are moved to the first position. 1 is positioned (ST41).

  When the leading edge of the processing paper is detected by the second sensor 21 after the swing guides 31 and 32 occupy the first position (ST42), the respective paper leading edge stoppers 28 and 30 are the same as when the second mode is selected. And the skew correction of the processing sheet is performed (ST43). After a predetermined time has elapsed, the control means 41 sends an operation command to the brushless motor 44 to rotate the rollers 23, 24, 25, and 26, respectively. At this time, the control means 41 increases the rotational peripheral speed of each roller 23, 24, 25, 26 to 1200 mm / sec. As a result, the processed paper is fed into the Z-folding means 22 in the same manner as when the second mode is selected. Then, the sheet is conveyed upward and then sent to the sheet conveyance path 4.

  The processed paper sent to the paper transport path 4 is detected by the exit sensor 8 when it is discharged to the outside by the paper discharge roller pair 7 (ST44), and a detection signal is sent to the control means 41. When the rear end of the processing sheet has passed through the exit sensor 8, the detection signal sent from the exit sensor 8 is turned off. Thereafter, the same process as described above is repeated until the final processing sheet is reached, and the detection signal that the rear end of the final processing sheet passes through the outlet sensor 8 and is sent from the outlet sensor 8 to the control means 41 is turned off. When this is done (ST45), a stop command is sent from the control means 41 to each actuator (ST46), and the sheet post-processing device 3 enters a standby state. The processed paper subjected to the Z-folding process is stacked on the paper discharge tray 3c.

  If the control means 41 determines in ST38 that the sheet is a non-processed sheet that does not perform the Z-folding process, the respective guide detection sensors 39, 40 are turned on, and the first swing guide 31 and the second swing guide 32 are turned on. It is determined whether or not each occupies the first position (ST47). If it occupies the first position, an operation command is sent to a swing means (not shown) (ST48), and the swing guides 31, 32 are sent. Are each positioned at the second position (ST49).

  When the leading edge of the non-processed sheet is detected by the second sensor 21 after the swing guides 31 and 32 occupy the second position (ST42), each sheet leading edge stopper 28, The position deviation of 30 is prevented and the skew correction of the unprocessed paper is performed (ST43). After a predetermined time has elapsed, the control means 41 sends an operation command to the brushless motor 44 to rotate the rollers 23, 24, 25, and 26, respectively. At this time, the control means 41 does not change the rotational peripheral speeds of the rollers 23, 24, 25, and 26 at 800 mm / sec.

  The non-processed paper whose front end is in contact with the nip portion of the first roller pair 34 is conveyed upward by the rotation of the rollers 23 and 24 (see FIG. 10A) and occupies the second position. The advancing direction of the first swing guide 31 is changed so as to be directed to the second roller pair 35 (see FIG. 10B). Thereafter, when the non-processed paper is further transported by the rotation of the transport roller pairs 11, 12, 13, 14 and the rollers 23, 24, the leading end of the non-processed paper is held by the second roller pair 35 ( (Refer to FIG. 10 (c)).

  The leading edge of the non-processed paper conveyed to the lower left by the second roller pair 35 contacts the leading edge of the second swing guide 32 occupying the second position, and the traveling direction of the leading edge of the second roller guide 32 is the third roller. It changes so that it may go to the pair 36 (refer FIG.10 (d)). Thereafter, when the sheet is further conveyed by the rotation of each of the conveying roller pairs 11, 12, 13, and 14 and the rollers 23 and 25, the leading end of the non-processed sheet is held by the third roller pair 36 (FIG. 10). (See (e)) It is conveyed upward (see FIG. 10 (f)).

  The unprocessed paper transported upward by the third roller pair 36 is sent into the exit-side paper transport path 19, and further transported upward by the respective transport roller pairs 15, 16, 17, and then the paper transport path. Sent to 4. The unprocessed paper sent to the paper transport path 4 is detected by the exit sensor 8 when it is discharged out of the apparatus by the paper discharge roller pair 7 (ST44), and a detection signal is sent to the control means 41. When the trailing edge of the non-processed paper has passed through the exit sensor 8, the detection signal sent from the exit sensor 8 is turned off. Thereafter, the same process as described above is repeated until the final non-processed paper is reached, and the trailing edge of the final non-processed paper passes through the outlet sensor 8 and is sent from the outlet sensor 8 to the control means 41. Is turned off (ST45), a stop command is sent from the control means 41 to each actuator (ST46), and the sheet post-processing apparatus 3 enters a standby state. The non-processed paper that has passed through the paper post-processing device 3 without being subjected to the Z-folding process is stacked on the paper discharge tray 3c.

  With the configuration described above, according to the sheet post-processing apparatus 3 of the present invention, all sheets on the electrophotographic copying apparatus 2 side in which the sheet post-processing apparatus 3 does not perform the Z-folding process on all sheets. In this case, it is possible to select either the second mode in which the sheet post-processing apparatus 3 performs the Z-folding process or the third mode in which only a part of the sheets is subjected to the Z-folding process in the sheet post-processing apparatus 3. At the same time, the processing paper that performs the Z-folding process and the non-processed paper that does not perform the Z-folding process can pass through the inside of the sheet post-processing device 3 to be substantially equal, so that a reduction in productivity can be prevented. it can.

  In the above embodiment, the entrance roller pair 5 is rotationally driven by the variable speed stepping motor 42. However, the rotational peripheral speed of the entrance roller 5 is different depending on whether the Z-folding process is performed or not. Since there is no change, it is not always necessary to use a variable speed motor. However, when the sheet post-processing apparatus 3 can be connected to a plurality of image forming apparatus main bodies, the sheet conveying speed from the discharge port 2b is different in each image forming apparatus. Therefore, by using a variable speed motor. It becomes possible to provide a sheet post-processing apparatus that can handle a plurality of image forming apparatuses.

  In the above embodiment, as the Z-folding means 22, one driving roller 23, the driven roller 24 and the driven roller 25 that are in pressure contact with the driving roller 23, and the driven roller 26 that is in pressure contact with the driven roller 25 are disposed. And the driven roller 24 constitute a first roller pair 34, the driving roller 23 and the driven roller 25 constitute a second roller pair 35, and the driven roller 25 and the driven roller 26 constitute a third roller pair 36. Although an example is shown, each of the roller pairs 34, 35, and 36 may be configured as a roller pair including one driving roller and one driven roller, and each driving roller may be rotationally driven.

  In the above embodiment, the electrophotographic copying apparatus 2 is used as the image forming apparatus main body to which the paper post-processing apparatus 3 is connected. However, the image forming apparatus 1 may be configured by connecting the sheet post-processing apparatus 3 to a printer, a facsimile machine, a plotter, a printing apparatus, a multifunction machine, or the like.

1 is a schematic front view of an image forming apparatus employing an embodiment of the present invention. It is a schematic front view of the paper post-processing apparatus used in one embodiment of the present invention. It is a block diagram of the control means used for one Embodiment of this invention. 6 is a flowchart for explaining a positioning operation of a first paper front end stopper and a second paper front end stopper in one embodiment of the present invention. 10 is a flowchart for explaining the operation of the sheet post-processing apparatus when a second mode is selected in an embodiment of the present invention. It is a schematic diagram which shows a mode that the paper in one Embodiment of this invention is Z-folded. It is the schematic explaining the behavior of a paper in case Z folding is performed in the Z folding means in one Embodiment of this invention. 10 is a flowchart for explaining the operation of the sheet post-processing apparatus when a third mode is selected in an embodiment of the present invention. 10 is a flowchart for explaining the operation of the sheet post-processing apparatus when a third mode is selected in an embodiment of the present invention. It is the schematic explaining the behavior of a sheet | seat when Z folding is not performed in the Z folding means in one Embodiment of this invention.

Explanation of symbols

1 Image forming apparatus 2 Image forming apparatus main body (electrophotographic copying machine)
DESCRIPTION OF SYMBOLS 3 Paper post-processing apparatus 5 Inlet roller pair 9 Inlet side conveyance means 10 Outlet side conveyance means 11, 12, 13, 14 Conveyance roller pair 19 Paper discharge conveyance path (exit side paper conveyance path)
21 Paper leading edge detection means (second sensor)
22 Z-folding means 23 Drive roller 24 First driven roller (driven roller)
25 Second driven roller (driven roller)
26 Third driven roller (driven roller)
27 1st processing conveyance path 28 1st stop member (1st paper front end stopper)
29 Second processing conveyance path 30 Second stop member (second paper front end stopper)
31 1st guide member (1st rocking | fluctuation guide)
32 Second guide member (second swing guide)
34 First roller pair 35 Second roller pair 36 Third roller pair

Claims (7)

A paper post-processing apparatus connected to an image forming apparatus main body, capable of receiving a paper discharged from the image forming apparatus main body, performing a Z-folding process on the paper by a Z-folding unit, and discharging the paper. ,
The Z-folding means is disposed so as to be movable to the first processing conveyance path so as to stop the front end of the processing sheet and the first roller pair that conveys the processing sheet to be Z-folded to the first processing conveyance path. A first stop member provided, and a bend formed when the processing sheet whose leading end is stopped by the first stop member is further conveyed by the first roller pair, is sandwiched between the first processing sheet and the first processing member. A second roller pair that forms a fold and conveys it to the second processing conveyance path, and a second stop that is movably disposed on the second processing conveyance path to stop the tip of the first fold. A second crease is sandwiched between the member and a bend formed when the processing sheet whose first fold is stopped by the second stop member is further conveyed by the second roller pair. Formed and transported to the paper discharge transport path A first position for guiding the processing sheet that has passed through the first roller pair to the first processing conveyance path, and a second non-processing sheet that does not perform the Z-folding process that has passed through the first roller pair. A first guide member that selectively occupies a second position for guiding the second roller pair, a first position for guiding the processing sheet that has passed through the second roller pair to a second processing conveyance path, and a second position. A second guide member that selectively occupies a second position for guiding the non-processed paper that has passed through the second roller pair to the third roller pair;
When the processing paper and the non-processing paper are continuously conveyed to the Z-folding unit, the processing paper positions the first guide member and the second guide member at the first positions, respectively. The non-processed paper is conveyed after passing through the first processing conveyance path and the second processing conveyance path, and the first processing conveyance is performed by positioning the first guide member and the second guide member at the second position, respectively. A sheet post-processing apparatus that conveys the sheet without passing through the path and the second processing conveyance path, and makes the sheet conveyance speed of the processing sheet faster than the sheet conveyance speed of the non-processing sheet . The sheet post-processing apparatus according to claim 1,
Inlet side conveying means for conveying the treated paper and non-treated paper toward the Z-folding means, and outlet-side conveying means for conveying the treated paper and non-treated paper sent out from the Z-folding means. And a sheet post-processing apparatus, wherein the Z-folding means and the transporting means of each of the transporting means at the time of transporting the treated paper are made faster than the speed of transporting the non-processed paper. The sheet post-processing apparatus according to claim 2 ,
The first roller pair is composed of a driving roller that is rotationally driven and a first driven roller that is disposed in pressure contact with the driving roller and can be driven to rotate. The second roller pair is disposed in pressure contact with the driving roller and can be driven to rotate. The third roller pair is composed of a second driven roller and a third driven roller which is disposed in pressure contact with the second driven roller and can be driven to rotate. The rotational peripheral speed of the driving roller is A sheet post-processing apparatus that can be changed and that each driven roller rotates following the rotation of the driving roller . In the paper post-processing apparatus according to claim 3,
A sheet leading edge detecting unit disposed immediately upstream in the sheet conveying direction of the first roller pair, and the driving roller is driven to rotate at a predetermined timing after the leading edge of the sheet is detected by the sheet leading edge detecting unit. sheet post-processing apparatus characterized by that. In the paper post-processing apparatus according to any one of claims 2 to 4 ,
The entrance-side transport unit includes a pair of entrance rollers that transports the sheet discharged from the image forming apparatus main body to the downstream side, and a pair of transport rollers that transports the sheet sent from the pair of entrance rollers to the Z-folding unit. The sheet post-processing apparatus is characterized in that the inlet roller pair and the transport roller pair are rotationally driven by different driving means, and the rotational peripheral speeds thereof can be changed independently of each other . The sheet post-processing apparatus according to claim 5 , wherein
The entrance roller pair has a connection / disconnection means, and when the leading edge of the sheet discharged from the image forming apparatus main body is inserted into the transport roller pair disposed immediately downstream of the entrance roller pair The sheet post-processing apparatus is configured such that the rotational driving force from the driving means is cut off and the sheet is conveyed by the pair of conveying rollers so as to be driven to rotate . An image forming apparatus comprising the sheet post-processing apparatus according to claim 1.

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