JP2007084268A - Sheet retention device, sheet distributing device, sheet processing device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet processing device and an image forming device equipped with an enhanced commercial value by reducing the noise and vibration of a buffer unit 140, shown in Patent Publication 2003-081517, without involving an addition of component part or an alteration of the design. <P>SOLUTION: A tail holder 135 is borne by a shaft 183 to rotate in a single piece with a tail holding arm 181 and is put in pressure contact with a lower transport guide 123b while it is energized by a holder spring 180. A buffer paper hold-down solenoid SL3 is put on to generate such a condition as separating from the lower transport guide 123b, and then put off, and immediately before the tail holder 135 collides with the lower transport guide 123b, the solenoid SL3 is put on for 10 msec, and thereby the tail holder 135 is decelerated to relieve the shock at the time of colliding with the lower transport guide 123b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention accepts a sheet discharged from an image forming apparatus such as a sheet holding device, a copying machine, a printer, a facsimile machine, a multi-function peripheral, or other office machine, which is arranged in a sheet conveyance path and retains the sheet. The present invention relates to a sheet processing apparatus that can stay in the apparatus, a sheet sorting apparatus that switches a conveyance path by a flapper member, a sheet processing apparatus that includes a sheet sorting apparatus, and an image forming apparatus that incorporates / connects these sheet processing apparatuses.

  2. Description of the Related Art In recent years, sheet processing apparatuses such as a sorter for sorting image-formed sheets have been developed as options for image forming apparatuses such as electrophotographic copying machines and laser beam printers. In addition, this type of sheet processing apparatus has a variety of functions such as stacking / aligning a certain amount of sheet materials, and providing a stapler for stapling to create a sheet bundle as well as a sorting function.

  In an old type sheet processing apparatus equipped with a stapler, a predetermined number of sheets received from the image forming apparatus to the conveyance path are stacked on a post-processing tray to form a sheet bundle, and then the stapler is moved along the edge of the sheet bundle. In this case, since the predetermined portion corresponding to the sheet size is stapled, the next sheet cannot be received on the conveyance path for a while after the sheet bundle is formed. Accordingly, a discharge prohibition signal is transmitted to the image forming apparatus side, and the acceptance is resumed after the stapled sheet bundle is completely discharged and the post-processing tray is empty.

  In contrast, the sheet processing apparatus disclosed in Patent Document 1 is provided with a sheet retention device in the sheet conveyance path, and continuously receives sheets from the image forming apparatus even during a period in which the sheets cannot be discharged / stacked on the post-processing tray. be able to. The sheet retention device accumulates a plurality of sheets in the conveyance path and retains them, and when the staple-bound sheet bundle is discharged from the post-processing tray, the plurality of retained sheets are collectively conveyed to the post-processing tray. Accordingly, image formation and staple binding can be performed with high productivity without prohibiting the image forming apparatus from discharging the sheet.

JP 2003-081517 A

  In the sheet processing apparatus disclosed in Patent Document 1, an abutting member is axially fixed adjacent to a conveyance path, and the abutting member is biased to a support surface of the conveyance path using a torsion coil spring. Then, the electromagnetic solenoid is actuated to widen the gap between the rotating end of the contact member and the support surface, and the trailing end of the succeeding sheet is inserted into this gap one after another. The sheet is stopped and pinched by the rotating end of the contact member. Therefore, every time the sheet is sandwiched, a collision sound is generated between the support surface (sheet surface) of the conveyance path and the rotating end of the contact member.

  Although this collision sound is not so loud, it becomes conspicuous as the noise of each part in the sheet processing apparatus is reduced, and the speed of the image forming apparatus is increased, so that several 10 to 100 sheets are discharged per minute. As a result, the collision sound became a continuous beating sound, which caused the housing structure to vibrate, and became one of the main remaining noise sources of the sheet processing apparatus.

  However, if the torque of the torsion coil spring is weakened in order to weaken the impact force with which the rotating end of the abutting member collides with the support surface, the sandwiching force of the sheet by the abutting member is insufficient and the position of the low friction sheet is shifted. And omissions are likely to occur.

  Therefore, measures such as providing a torque limiter or damper for the mechanism of the contact member, replacing the electromagnetic solenoid with a step motor, or incorporating a soundproof material into the housing cover have been studied. It is not easy to find a space for adding new components, and extensive design and control changes are required. Further, the addition of new parts immediately increases the cost of parts, and the control becomes complicated with a step motor or the like, and the added soundproofing structure and silencer cause an increase in the size of the sheet processing apparatus.

  It is an object of the present invention to provide a sheet processing apparatus that can effectively reduce the operation noise of a contact member and a flapper member without causing a functional problem and avoiding the addition of new parts and design changes as much as possible. It is aimed.

  The sheet staying device of the present invention includes a contact member disposed so as to be able to contact a support surface of a sheet conveyance path, a biasing member that biases the contact member toward the support surface, A drive element that drives the contact member in a direction away from the support surface, and the drive element is configured to hold the sheet between the support surface and the contact member and retain the sheet in the conveyance path. The contact element is decelerated by the drive element during a period from when the drive is released until the contact member contacts the support surface, and the impact when the contact member contacts the support surface is reduced. To do.

  In the sheet staying device according to the present invention, when the driving element is released, the contact member accelerated by the urging member collides with the support surface or the sheet surface of the conveyance path. Since the contact member is decelerated to reduce the impact of the collision, it is possible to suppress noise generation and vibration without reducing the pinching force by the biasing member.

  More specifically, the sheet staying device includes a contact member disposed so as to be able to contact the support surface of the sheet conveyance path, and a biasing member that biases the contact member toward the support surface. A drive element that drives the contact member in a direction away from the support surface, a transport member that is disposed on the downstream side of the contact member and can transport the sheet in both forward and reverse directions of the transport path, and the transport After the member is operated in the forward direction to convey the sheet to the downstream side of the contact member, the drive element is operated to form a gap between the support surface and the contact member, and then the transfer Control means for releasing the operation of the drive element after conveying the sheet to the gap by operating the member in the reverse direction, and releasing the operation of the drive element to make the contact Until the member contacts the support surface The control means is realized by operating the driving element in a limited period, and more specifically, the energization to the driving element is stopped and the contact member is in contact with the support surface during the period. It is possible to employ control in which a short-time energization of the drive element is performed one or more times.

  In this case, the next sheet is conveyed in the forward direction by the conveying member on the sheet sandwiched between the contact member and the support surface and exerts a frictional force on the lower sheet, but the friction is caused by the clamping force by the urging force of the urging member. It resists the force and does not shift the position of the lower sheet or drop the lower sheet from being caught. This sufficient clamping force and light impact (low noise) due to deceleration can be achieved with only a slight control change in the existing drive elements.

  In any case, it is possible to suppress the noise and vibration without adding new parts, a soundproof structure and a silencer to the sheet staying apparatus disclosed in Patent Document 1, and without impairing the sheet staying and conveying quality, and the sheet staying. Realizing noise reduction, low vibration, improved reliability and durability by reducing vibration of sheet processing equipment incorporating the device, and achieving downsizing and higher performance of the image forming apparatus incorporating the sheet processing device it can.

  Hereinafter, a sheet staying apparatus according to an embodiment of the present invention, a sheet processing apparatus including the sheet staying apparatus, and a copying machine as an example of an image forming apparatus including the sheet processing apparatus will be described with reference to the drawings. The image forming apparatus includes a copying machine, a facsimile machine, a printer, and a complex machine of these, and the image forming apparatus equipped with the sheet processing apparatus is not limited to the copying machine.

  Further, the sheet retention device is not provided only in the sheet processing device, but may be provided in a sheet conveyance path or a sheet discharge unit of an image forming apparatus that is not equipped with the sheet processing device, and is described in the present embodiment. The dimensions, numerical values, materials, shapes, relative arrangements, and the like of the components are not intended to limit the scope of the present invention only to those unless otherwise specified.

  In the present exemplary embodiment, a case where the sheet processing apparatus is an independent apparatus configured to be detachable from the apparatus main body of the image forming apparatus as an independent apparatus will be described as an example. However, the present invention is also applied to a case where the sheet processing apparatus is integrally stored in the housing of the image forming apparatus or directly controlled by the control unit of the image forming apparatus without having an independent control unit. Needless to say. In these cases, there is no particular functional difference from the case of the sheet processing apparatus described below, and a description thereof will be omitted. Specifically, the sheet processing apparatus is, for example, a finisher.

(Image forming device)
FIG. 1 is an explanatory diagram of an image forming apparatus to which the sheet processing apparatus of this embodiment is mounted, and FIG. 2 is a block diagram of a control system of the image forming apparatus.

  As shown in FIG. 1, the copying machine 100 includes an apparatus main body 101 and a sheet processing apparatus 119. A document feeder 102 is provided on the upper part of the apparatus main body 101. The document D is placed on the document placing unit 103 by the user, and is sequentially separated one by one by the feeding unit 104 and supplied to the registration roller pair 105. Subsequently, the document D is temporarily stopped by the registration roller pair 105, a loop is formed, and skew is corrected. Thereafter, when the document D passes through the introduction path 106 and passes through the reading position 108, the image on the front surface is read. The document D that has passed the reading position 108 passes through the discharge path 107 and is discharged onto the discharge tray 109.

  When reading both the front and back sides of the document D, first, the document D passes through the reading position 108 as described above, and an image on one side is read. Thereafter, the document D passes through the discharge path 107, is switched back by the reverse roller pair 110 immediately before being discharged onto the discharge tray 109, and is sent again to the registration roller pair 105 in a state where the front and back are reversed.

  Then, in the same manner as when the image on one side is read, the skew of the original D is corrected by the registration roller pair 105, and the image on the other side is read at the reading position 108 through the introduction path 106. It is done. Then, the document D passes through the discharge path 107 and is discharged to the discharge tray 109.

  On the other hand, the image of the document D passing through the reading position 108 is irradiated with light from the illumination system 111. Reflected light reflected from the document D is guided by a mirror 112 to an optical element 113 (CCD or other element) and converted into an electrical signal to form image data. Then, a laser beam based on the image data is irradiated onto, for example, the photosensitive drum 114 serving as an image forming unit to form a latent image. Although not shown, the mirror 112 may be configured to directly irradiate the photosensitive drum 114 with reflected light to form a latent image.

  The latent image formed on the photosensitive drum 114 is further developed with toner supplied from a toner supply device (not shown) to form a toner image. The cassette 115 stores a sheet P which is a recording medium such as paper or plastic film. The sheet P is sent out from the cassette 115 in accordance with the rotational phase of the photosensitive drum 114 and enters between the photosensitive drum 114 and the transfer device 116. Then, the toner image on the photosensitive drum 114 is transferred to the sheet P by the transfer device 116. The sheet P on which the toner image has been transferred is fixed by the heat and pressure of the fixing device 117 while passing through the fixing device 117.

  When images are formed on both sides of the sheet P, the sheet P on which the image is fixed on one side by the fixing device 117 passes through the double-sided path 118 provided on the downstream side of the fixing device 117, and is switched back and conveyed again. Then, the toner image is transferred between the photosensitive drum 114 and the transfer device 116, and the toner image is also transferred to the back surface. Then, the toner image is fixed by the fixing device 117 and is discharged to a sheet processing apparatus (finisher) 119.

  As shown in FIG. 2, the entire copying machine 100 is controlled by a CPU circuit unit 200. The CPU circuit unit 200 includes a ROM 202 that stores a sequence of each unit, that is, a control procedure, and a RAM 203 that temporarily stores various pieces of information as necessary. The document feeder control unit 204 controls the document feeding operation of the document feeder 102. The image reader control unit 205 controls the illumination system 111 and the like to control reading of a document. The image signal control unit 206 receives the reading information of the image reader control unit 205 or the image information sent from the external computer 207 via the external I / F 208, processes the information, and processes the printer control unit. A processing signal is sent to 209. The printer control unit 209 controls the photosensitive drum 114 and the like based on the image processing signal from the image signal control unit 206 to form an image on the sheet P.

  The operation unit 210 can input sheet size information when the user uses the copier 100, what kind of processing is to be performed on the sheet, for example, information on stapling, and the like. 101 and information such as the operation state of the sheet processing apparatus (finisher) 119 can be displayed. The finisher control unit 211 is configured by an arithmetic device independent of the CPU circuit unit 200, and controls the operation in the sheet processing apparatus 119 in accordance with an instruction from the CPU circuit unit 200. The FAX control unit 212 controls the copier 100 so that the copier 100 can be used as a fax, and communicates with other faxes via a telephone line to exchange image signals.

(Sheet processing equipment)
3 is an explanatory diagram of the configuration of the sheet processing apparatus, FIG. 4 is an explanatory diagram of a drive system of the sheet conveyance path, FIGS. 5 to 7 are explanatory diagrams of the operation of the rear end assist, and FIG. 8 is an explanatory diagram of the control system of the sheet processing apparatus. FIG. 9 is a flowchart of sheet discharge control, FIG. 10 is a diagram of the conveyance speed of the trailing edge assist and the swing roller pair, FIG. 11 is a diagram of the conveyance speed of the trailing edge assist, and FIG. It is a diagram of a conveyance speed.

  As shown in FIG. 3, the sheet processing apparatus 119 has a staple binding function for binding the vicinity of the edge of the sheet bundle with the stapler 132, the center of the sheet bundle with the stapler 138, and the binding position is folded by the folding unit 139. And a bookbinding function. On the side surface of the sheet processing apparatus 119, stacker trays 128 and 155 that can be moved / positioned to any desired height position, and a fixed saddle tray 157 are arranged, and a bundle of sheets stapled by the stapler 132 is stacked on the stacker tray 128. 155 and the sheet bundle formed into a booklet by the folding unit 139 are stacked on the saddle tray 157, respectively.

  Further, the sheet processing apparatus 119 includes a buffer unit 140 that accumulates (buffers) a plurality of sheets P in a straight state when the stapler 132 is operated. As shown in Patent Document 1, since the buffer unit 140 accumulates a plurality of sheets P in a straight state and retains them, unlike the conventional mechanism for retaining the sheets P around the buffer roller, the buffer unit 140 is flat. Therefore, the sheet processing apparatus 119 can be reduced in size and weight. Further, since the sheet P can be retained in a straight state, the sheet can be handled easily without rounding the sheet like a buffer roller, and the sheet processing time as the sheet processing apparatus 119 can be shortened accordingly. Can do.

  As shown in FIG. 4, the sheet P received by the receiving roller pair 137 from the apparatus main body 101 (FIG. 1) can be switched between the horizontal conveyance path R <b> 1 and the lower conveyance path R <b> 2 by the flapper 122. The transport path R1 guides the sheet P from the buffer unit 140 to the processing tray 129, and the transport path R2 guides the sheet P from the stapler 138 shown in FIG. 3 to the folding unit 139.

  The sheet P traveling on the conveyance path R1 is conveyed from the receiving roller pair 137 to the swing roller pair 127 via the inlet roller pair 121, the buffer roller 124, and the first paper discharge roller pair 126. The inlet transport motor M2 rotates the inlet roller pair 121, the buffer roller 124, and the first paper discharge roller pair 126. The bundling motor M3 rotates the swing roller pair 127 and the return roller 130. The bundle lowering clutch CL transmits or rejects the rotation of the bundle unloading motor M3 to the lower roller 127b.

  Since the lower roller 127b and the return roller 130, which will be described later, are rotated by a common bundle motor M3, the lower bundle clutch CL slips when the lower roller 127b and the return roller 130 convey a sheet or sheet bundle. This is provided to absorb the difference in speed because there is a risk that the sheet or the sheet bundle may be wrinkled or damaged when a difference in sheet conveyance speed occurs between both rollers.

  As shown in FIG. 8, the sheet processing apparatus 119 is controlled by the finisher control unit 211. In the CPU 221 of the finisher control unit 211, a control sequence (sequence) of the sheet processing apparatus 119 operating based on an instruction from the CPU circuit unit 200 of the apparatus main body 101, various individual control programs as shown in FIG. A ROM 222 that stores data necessary for these processes, a RAM 223 that stores information necessary to control the sheet processing apparatus 119 each time, and the like are provided. Further, a paper surface detection sensor 223 that operates based on an operation of a paper surface detection lever 133 described later is connected to the finisher control unit 211. The CPU 221 moves the stack tray 128 up and down based on the sheet detection signal from the paper surface detection sensor 223.

  The finisher control unit 211 refers to the outputs of a plurality of sensors arranged on the transport path R1 according to the above sequence, and operates the inlet transport motor M2, the bundle motor M3, the bundle lower clutch CL, and the like.

(Explanation for binding and discharging sheet bundles)
13 to 19 are explanatory views of sheet conveyance in post-processing in which sheets are not buffered.

  When the sheet binding process display displayed on the operation unit 210 of the apparatus main body 101 is selected by the user, the CPU circuit unit 200 of the apparatus main body 101 controls each part of the apparatus main body 101 to move the copying machine 100 to a copying operation. And sends a sheet binding processing signal to the finisher control unit 211.

  The operation description based on FIGS. 13 to 19 is based on the case where the CPU circuit 200 determines that the sheet length is long based on the sheet size information input by the user to the operation unit 210 (for example, in the case of A3 size, for example). ) Or a case where the sheet is a special sheet having an attribute different from that of a normal sheet, such as thick paper, thin paper, tab paper, and color paper, depending on the sheet type information. That is, the operation description based on FIGS. 13 to 19 is an operation description of stacking sheets on the processing tray 129, performing a stapling process, and discharging a sheet bundle after the post-processing to the stacking tray 128. However, the operation described below may be performed regardless of the length of the sheet and whether or not the sheet is a special sheet.

  The finisher control unit 211 starts the entrance conveyance motor M2 and the bundling motor M3 based on the sheet binding processing signal. Further, as shown in FIG. 13A, the finisher control unit 211 operates the buffer roller separation solenoid SL1 (see FIG. 4) to separate the buffer roller 124 from the lower conveyance guide plate 123b, which will be described later. The upper roller 127a of the swing roller pair 127 is separated from the lower roller 127b by operating the swing roller mechanism. The start / stop of the entrance conveyance motor M2 and the bundling motor M3 may be controlled step by step in accordance with the movement of the sheet P.

  The first sheet sent from the discharge roller pair 120 (FIG. 1) of the apparatus main body 101 is guided to the inlet roller pair 121 by the receiving roller pair 137 and the flapper 122 shown in FIG. The receiving roller pair 137 is rotated by a common conveyance motor M1 that rotates the discharge roller pair 120 of the apparatus main body 101.

  As shown in FIG. 13A, the inlet roller pair 121 is rotated by an inlet conveyance motor M2 (FIG. 4) to convey the first sheet P1. The sheet P1 is conveyed to the first paper discharge roller pair 126 by the guide 123 formed by the upper conveyance guide plate 123a and the lower conveyance guide plate 123b.

  As shown in FIG. 13B, the sheet P1 is further conveyed by the rotation of the first paper discharge roller pair 126, and passes through the first paper discharge roller pair 126 as shown in FIG. 14A. Then, as shown in FIG. 14 (b), it falls across the stack tray 128 and the processing tray 129. Thereafter, as shown in FIGS. 15A and 15B, the upper roller 127a is lowered by a swing roller mechanism described later, and the sheet P1 is sandwiched between the lower roller 127b. The upper roller 127a and the lower roller 127b are rotated in the direction of the arrow by the bundling motor M3 (FIG. 4), and the sheet P1 runs backward to the back side of the processing tray 129. At this time, the return roller 130 that can contact and separate from the processing tray 129 is also in contact with the processing tray 129 and rotated in the direction of the arrow, and drives the sheet P1 to the back side of the processing tray 129.

  Meanwhile, the lower roller 127b of the swing roller pair 127 is connected to the first sheet P1 by the operation of the lower bundle clutch CL (FIG. 4), but the second and subsequent sheets Pn are connected. On the other hand, the lower bundle clutch CL is turned off to idle. This is because if the lower roller 127b is rotated when the second and subsequent sheets Pn are stacked after the first sheet P1 is stacked on the processing tray 129, the lower roller 127b This is because the sheet P1 may be pushed further toward the stopper 131 to cause a jam or a wrinkle.

  Thereafter, as shown in FIG. 16A, the sheet slides down on the processing tray 129 that is lowered to the right by the rotation of the swing roller pair 127 and the return roller 130. At this time, the rear end assist 134 is in a standby position at the innermost standby position. When the sheet P1 comes into contact with the stopper 131, the upper roller 127a is separated from the sheet P1. At that time, alignment in the sheet conveyance direction is performed, and then the pair of alignment plates 144 shown in FIG. 5 are reciprocated to align the sheet P1 in the width direction.

  Thereafter, the subsequent sheets P2, P3,... Pn are similarly stacked on the processing tray 129. As shown in FIG. 17, when a predetermined number of sheets P1, P2,... Pn are stacked on the processing tray 129, the stapler 132 shown in FIG. The staple binding process is executed at the designated position in two places. The sheet bundle may be punched by a punch unit (not shown) instead of being bound by the stapler 132.

  When the staple binding process is completed, sheet bundle discharge control is executed as shown in FIG. In step S101, as shown in FIG. 18A, the upper roller 127a descends again, and the sheet bundle is sandwiched between the lower roller 127b.

  In step S102, the lower bundle clutch CL is actuated to prepare for discharging by the swing roller pair 127, and in step S103, 150 msec is awaited. When 150 msec has elapsed, in step S104, the alignment plate 144 shown in FIG. 5 is retracted from the sheet bundle to the side, and in step S105, the stack tray 128 shown in FIG. 18A is detected by the paper surface detection lever 133. It moves to the position and waits at a position where it can easily receive the discharged sheet bundle.

  In step S106, the bundling motor M3 shown in FIG. 4 is operated to start the rotation of the swing roller pair 127, and the upper roller 127a and the lower roller 127b sandwich the sheet bundle P as shown in FIG. 18B. Then, the sheet bundle P is sent out toward the stack tray 128 by rotating in the direction of the arrow, while the rear end assist 134 shown in FIG. 5 pushes the rear end of the sheet bundle P to push out the sheet bundle P. As shown in FIGS. 5 to 7, the rear end assist 134 is provided on the belt 142 that rotates forward / reversely by the rear end assist motor M <b> 4, and reciprocates along the processing tray 129.

  At this time, as shown in FIG. 10, the start time (T1) and the start speed (132 mm / sec) of the swing roller pair 127 and the rear end assist 134 are the same, and the same acceleration end speed (500 mm / sec) is the same time. When reaching (T2), the swing roller pair 127 and the rear end assist 134 can discharge the sheet bundle P without applying a pulling force or a compressing force to the sheet bundle P.

  However, as shown in FIG. 11, the starting speed of the rear end assist 134 is higher than the starting speed of the swing roller pair 127 by belts 143, 142 and the like that transmit the rotational force of the rear end assist motor M4 to the rear end assist 134. In some cases, it may be fast (assuming 300 mm / sec). In such a case, if activated at the same time, the trailing edge assist 134 precedes and compresses the sheet bundle P. Therefore, in step S107, the rear end assist 134 is stopped without starting to move until the time T3 when the sheet conveying speed of the rocking roller pair 127 is 300 m / sec, and the sheet conveying speed of the rocking roller pair 127 is reached. Then start moving. That is, the rear end assist 134 is started in step S108 after (T3−T1) = ΔT time after the swing roller pair 127 is started.

  If the starting speed of the swing roller pair 127 is faster than that of the rear end assist 134, the start time of the swing roller pair 127 is delayed by ΔT. If the activation speed of the rear end assist 134 and the activation speed of the rear end assist 134 are the same, ΔT is zero.

  As described above, when the time difference ΔT is provided at the time of starting, the swing roller pair 127 and the rear end assist 134 pull the pulling force on the sheet bundle even if the difference in the starting speeds is matched between the swing roller pair 127 and the rear end assist 134. The sheet bundle P can be discharged to the stack tray 128 in a coordinated manner without applying a compression force. Further, the rubbing trace of the roller by the swing roller pair 127 is not attached to the sheet, and the quality of the sheet bundle and the image quality of the sheet bundle are not deteriorated.

  In step S <b> 108, the sheet bundle P is started to be fed toward the stack tray 128 by the swing roller pair 127, the rear end assist 134, and the return roller 130. In step S109, the feed amount is measured, and when the discharge distance of the sheet bundle P reaches 15 mm, the process proceeds to step S110, where the rear end assist 134 returns to the original position (home position) ("HP delivery control" in FIG. 12). Equivalent to ").

  In the sheet processing apparatus 119 of the present embodiment, the trailing edge assist 134 pushes the trailing edge of the sheet bundle and conveys the sheet bundle. Therefore, unlike the case where the sheet bundle is discharged by rotating the roller against the surface of the sheet bundle, The sheet bundle can be reliably conveyed without damaging the surface of the sheet bundle.

  Thereafter, the sheet bundle P is further fed out from the state shown in FIG. 18B, and is discharged onto the stack tray 128 by the upper roller 127a and the lower roller 127b as shown in FIG. Thereafter, in step S111, the bundle motor M3 is decelerated / stopped, the bundle lowering clutch CL is turned off, and the swing roller pair 127 is separated. In step S112, when the upper roller 127a of the decelerating rocker pair 127 is completely separated from the lower roller 127b, the series of sheet bundle discharging operations ends.

  On the other hand, as shown in FIG. 18B, when the sheet bundle P starts to be discharged to the stack tray 128, the first sheet P1 belonging to the next sheet bundle is sent to the inlet roller pair 121. As shown in FIG. 19, after the discharge of the sheet bundle P to the stack tray 128 is completed, the swing roller pair 127 is separated, and the first sheet P1 is discharged / stacked from the first discharge roller pair 126 to the processing tray 129. Is done. Throughout FIGS. 13 to 19, the buffer roller 124 is always kept in a separated state and is not functioning.

(Description of buffer operation)
The above description of the operation is, for example, an operation description in the case where the conveyance interval between sheets is wide and the sheet bundle P can be bound while the next sheet P1 is being fed. In the explanation of the operation to be performed, when the conveyance interval between the sheets is narrow and the sheet bundle P is being processed, if the subsequent first sheets P1, P2,. This is a description of the buffer operation.

  20 to 29 are explanatory views of sheet conveyance in post-processing performed by buffering sheets.

  When it is determined that the interval between sheets sent from the apparatus main body 101 is shorter than the sheet binding processing time, the CPU circuit unit 200 of the apparatus main body 101 transmits a buffer operation command to the finisher control unit 211. The sheet processing apparatus 119 performs a buffer operation based on the buffer operation command. In this case, the buffer roller 124 is lowered by the solenoid SL1 (FIG. 4) and is in contact with the lower conveyance guide plate 123b.

  As illustrated in FIG. 20A, the sheet bundle P is stacked on the processing tray 129 based on the operation described with reference to FIGS. 13 to 17. It is assumed that the sheet bundle P has been bound by the stapler 132 (see FIG. 4).

  As shown in FIG. 20A, when the first sheet P1 belonging to the next sheet bundle is sent while the stapling process is being performed on the sheet bundle P stacked on the processing tray 129. The sheet P1 is fed to the buffer roller 124 by the inlet roller pair 121. The buffer roller 124 is rotated by an inlet conveyance motor M2 (see FIG. 4) to convey the sheet P1 downstream.

  At this time, the upper discharge roller 126a of the first discharge roller pair 126 is separated from the lower discharge roller 126b by the first discharge roller separation solenoid SL2 (see FIG. 4). However, the first discharge roller separation solenoid SL2 is not shown in FIG. 4 because it appears to overlap the buffer roller separation solenoid SL1 at the angle shown in FIG.

  The upper roller 127a of the swing roller pair 127 is also separated from the lower roller 127b by a swing roller mechanism described later.

  As shown in FIG. 20B, when the rear end of the sheet P1 reaches the switchback point SP, the buffer roller 124 starts to reverse as shown in FIG. Back to the side. At substantially the same time, the rear end press 135 is separated from the lower transport guide plate 123b, and the rear end receiving portion 136 is opened.

  The arrival of the sheet P1 at the switchback point SP is a predetermined time after the entrance sensor S1 disposed near the downstream side of the entrance roller pair 121 shown in FIG. Alternatively, it can be detected by the rotational speed of the buffer roller 124 or the like.

  The upstream end side of the sheet P1 switched back by the buffer roller 124 is received by the rear end receiving portion 136 as shown in FIG. After that, as shown in FIG. 21B, the rear end presser 135 returns to its original position and presses the sheet P1 against the lower transport guide plate 123b by the friction member 141 provided on the rear end presser 135.

  Thereafter, as shown in FIG. 22A, the second sheet P2 is fed. The second sheet P <b> 2 is conveyed by the entrance roller pair 121 and passes over the rear end press 135. The sheet P2 is also conveyed by the buffer roller 124 as shown in FIG. At this time, the first sheet P1 is pressed against the lower conveyance guide plate 123b together with the second sheet P2 by the buffer roller 124, and follows the second sheet P2 conveyed to the downstream side. Try to move. However, since the first sheet P1 is pressed against the lower conveyance guide plate 123b by the holding force of the presser spring 180, which will be described later, and the friction member 141 provided on the rear end presser 135, the first sheet P1 can move. Absent.

  Similarly to the first sheet P1, the second sheet P2 also opens the trailing edge press 135 when the trailing edge reaches the switchback point SP, and is buffered by the buffer roller 124 as shown in FIGS. Returned upstream. Then, the second sheet P2 is pressed against the lower conveyance guide plate 123b by the friction member 141 of the rear end press 135 so as to overlap the first sheet P1.

  Assume that when the staple binding process on the processing tray 129 is completed, the third sheet P3 is sent as shown in FIG. Here, when the rear end of the sheet P3 passes through the entrance roller pair 121, as shown in FIG. 25B, the upper paper discharge roller 126a is lowered and the sheets P1, P2 are placed between the lower paper discharge roller 126b. , P3 is sandwiched together. The third sheet P3 slightly protrudes further downstream than the first and second sheets P1 and P2.

  At this time, since the binding process for the sheet bundle P on the processing tray 129 has been completed, the trailing edge assist 134 moves along the processing tray 129 as shown in FIG. Push up the rear edge. As a result, the downstream end Pa of the sheet bundle P protrudes by a length L further downstream than the downstream end P3a of the third sheet P3.

  Then, as shown in FIG. 26B, the upper roller 127a is also lowered, and the swing roller pair 127 sandwiches the three sheets P1, P2, P3 and the sheet bundle P together. Along with this, the rear end press 135 is opened, and the first sheet P1 and the second sheet P2 are released.

  Thereafter, the three sheets P1, P2, P3 and the sheet bundle P are conveyed by a pair of oscillating rollers 127 that rotate as shown in FIG. Then, as shown in FIGS. 27A and 27B, when the sheet bundle P is discharged to the stack tray 128, the rear ends of the first sheet P1 and the second sheet P2 are The upstream side of the three sheets P 1, P 2, and P 3 is received by the processing tray 129 after exiting from the one paper discharge roller pair 126.

  Here, as shown in FIG. 12, the first discharge roller pair 126, the swing roller pair 127, and the rear end assist 134 have the same start time (T1) and start speed (132 mm / sec), and the same acceleration end speed. When the same time (T2) is reached at (500 mm / sec), the first paper discharge roller pair 126, the swing roller pair 127, and the rear end assist 134 are moved to the sheet bundle P or the three sheets P1, P2, P3. Thus, the sheet bundle P can be discharged without applying a pulling force or a compressive force. However, if there is a difference in the starting speed, a time difference of ΔT is provided as in step S107 of FIG. 9 to start each of them, so that a tensile force or a compressive force is applied to the sheet bundle or three sheets. Thus, the sheet bundle can be discharged without adding. Further, the rubbing marks of the rollers by the first paper discharge roller pair 126 and the swing roller pair 127 are not attached to the sheet, and the quality of the sheet bundle and the image quality of the sheet bundle are not deteriorated.

  As shown in FIGS. 28A and 28B, the three sheets P 1, P 2, and P 3 are transported down on the processing tray 129 by the swing roller pair 127 and the return roller 130, and are transferred to the stopper 131. It is accepted.

  During this time, the stack tray 128 descends once, lowers the upper surface of the sheet bundle below the paper surface detection lever 133, then rises again, and stops rising when the paper surface detection lever 133 is actuated by the upper surface of the sheet bundle. To do. As a result, the upper surface of the sheet bundle P on the stack tray 128 can be held at a predetermined height. Thereafter, the fourth sheet P4 and the subsequent sheets are sequentially stacked on the processing tray 129 without being accumulated on the lower conveyance guide plate 123b, and are bound when a predetermined number of sheets are reached. During the binding operation, the first three sheets in the subsequent sheet bundle are collected on the lower conveyance guide plate 123b.

  In the above description, three sheets P1, P2, and P3 are collected on the lower conveyance guide plate 123b. The number of sheets (buffer sheets) to be accumulated is the sheet length, the binding time, and the sheet conveyance. Since it varies depending on the speed and the like, it is not limited to three.

  As described above, the sheet processing apparatus 119 of the present embodiment has the downstream end Pa of the sheet bundle P downstream of the downstream end P3a of the third sheet P3 as shown in FIG. Is projected by a length L. This is due to the following reason.

  As shown in FIG. 29, if the protruding length of the downstream end is shorter than the length L and the protruding from the sheets P1 and P2 is L1, the protruding length of the upstream end is also L1. For this reason, the length of gripping the three buffer sheets P1, P2, and P3 after the swing roller pair 127 ejects the sheet bundle P to the stack tray 128 is shortened, and the three buffer sheets P1, P2, There is a possibility that P3 is missed and cannot be reliably fed into the processing tray 129. Therefore, the sheet bundle P protrudes from the buffer roller by a length L so that the swing roller pair 127 can securely grasp the buffer sheets P1, P2, and P3 and send them to the processing tray 129. .

  Further, when the protruding length is short, the contact area between the buffer sheets P1, P2, and P3 and the sheet bundle P becomes wide, and the sheet bundle P comes into close contact with the buffer sheets P1, P2, and P3 and falls onto the stack tray 128. It tends to be late to do. In such a case, when the pair of rocking rollers 127 are reversed and the buffer sheets P1, P2, and P3 are fed into the processing tray 129, the sheet bundle P remains in close contact with the buffer sheets P1, P2, and P3. There is a possibility that the sheet bundle P will be damaged and the jam may be caused. Therefore, in order to improve the separation between the sheet bundle P and the buffer sheets P1, P2, and P3, the sheet bundle P is projected from the buffer sheets P1, P2, and P3 by the length L.

  FIG. 30 is a perspective view showing the configuration and driving of the swing roller mechanism. Here, the swing roller mechanism for separating / pressing the upper roller 127a of the swing roller pair 127 from the lower roller 127b will be described with reference to the drawings.

  The bracket 152 provided with the upper roller 127 a of the swing roller pair 127 rotates in the vertical direction about the shaft 153. A hook arm 152a is provided on the upper surface of the bracket 152, and a slide arm 160 that slides up and down so as to hook the hook arm 152a and rotate the bracket 152 up and down is provided in the vicinity thereof. It has been. The slide arm 160 slides on the slide shaft 161 and moves in the direction of the arrow x or y in the figure.

  The slide arm 160 has a rack-shaped portion so that the rocking gear 162 is engaged, and the slide arm 160 moves in the x and y directions when the rocking gear 162 rotates. Further, the swinging gear 162 is connected to the torque limiter 164, the intermediate gear a165, the intermediate gear b166, and finally the swinging motor gear 167 attached to the swinging motor M5 via the swinging shaft 163 to rotate. The drive is reported.

  Here, since the torque limiter 164 is provided between the intermediate gear 165 and the swinging shaft 163, a limit is applied when the driving force of the swinging motor M5 exceeds a certain force, resulting in idling. In addition, the pressing force for the upper roller 127a of the swing roller pair 127 to be clamped to the lower roller 127b is kept constant. Thereby, even if the thickness of the sheet bundle conveyed by the swing roller pair 127 changes depending on the number of sheets, the conveyance force can be made constant and stable conveyance performance can be secured.

(Buffer unit)
Next, when post-processing is not finished in the post-processing tray, the sheet transport standby mechanism that holds the sheet transported into the sheet processing apparatus at any time and waits for transport to the post-processing tray The operation and control method will be described in detail.

  FIGS. 31 and 32 are front views of the sheet conveyance standby mechanism that performs the sheet holding operation, and FIG. 33 is an explanatory diagram of ON duty control of the buffer sheet pressing solenoid SL3. The sheet processing apparatus 119 of the present embodiment includes, for example, a buffer paper pressing solenoid SL3 that is a driving element, a rear end pressing 135 that is an abutting member, a pressing spring 180 that is an urging unit, and an inlet roller that is an inlet conveyance member, for example. For example, a finisher control unit 211 that is a control unit and a pair 121 is provided.

  As shown in FIG. 31, when the sheet P1 to be held is conveyed by the entrance roller pair 121, the leading edge of the sheet P1 is detected by the entrance sensor S1. Here, the rear end presser 135 is pressed against the transport surface of the lower transport guide plate 123b through the rear end presser arm 181 by the weight of the rear end presser 135 itself and the compression force of the presser spring 180. Energized to the state. Further, the buffer paper pressing solenoid SL3 is in an OFF state, and the plunger 182 that performs the suction / sliding operation is in a state of being pulled out of the solenoid SL3 main body by the rear end pressing arm 181.

  The sheet P1 conveyed by the inlet roller pair 121 passes between the upper surface portion of the rear end press 135 and the upper conveyance guide 123a in pressure contact with the lower conveyance guide 123b, and is sent to the buffer roller 124. When the trailing edge of the sheet P1 reaches the switchback point SP, the buffer roller 124 rotates in the opposite direction to that of the sheet P1 and conveys the sheet P1 in the upstream direction.

  At substantially the same time, the rear end presser 135 is separated from the lower conveyance guide 123b and opens the rear end receiving portion 136 as shown in FIG. The driving method is a method of turning the rear end press 135 in the arrow Y direction via the rear end press arm 181 by turning on the buffer paper press solenoid SL3 and sucking the plunger 182 in the arrow X direction. . At this time, the holding spring 180 is pulled greatly to generate a large compressive force.

  The timing at which the sheet P1 reaches the switchback point SP and the trailing edge retainer 135 starts the separation operation is controlled by the conveyance distance or the conveyance time after the entrance sensor S1 is operated by the leading edge (or trailing edge) of the sheet. can do.

  When the trailing edge of the sheet P1 reaches the opened trailing edge receiving portion 136, the buffer roller 124 stops rotating and the sheet P1 conveyed by the buffer roller 124 also stops. After that, the rear end presser 135 turns the buffer paper presser solenoid SL3 OFF, so that the rear end presser 135 itself and the compression force of the presser spring 180 cause the lower transport guide 123b to pass through the rear end presser arm 181. It rotates to the position where it is pressed. Since the friction member 141 is provided on the lower surface of the rear end press 135, the sheet P1 is held by the sandwiching force and the large frictional force between the friction member 141 and the lower conveyance guide 123b. The friction member 141 can increase the holding force of the sheet P1.

  In the state shown in FIG. 32, the period from when the buffer paper pressing solenoid SL3 is turned off until the rear end pressing 135 collides with the lower conveyance guide 123b (while the rear end pressing 135 is rotating to the press contact position). ), On-duty control for a moment (about 10 msec in the experimental results) is performed by the buffer paper pressing solenoid SL3.

  As shown in FIG. 33, the buffer paper pressing solenoid SL3 is turned off at time h, and the buffer is held for time T3 (10 msec) at time T2 until the trailing edge press 135 collides with the lower conveyance guide 123b at time z. The paper holding solenoid SL3 is energized. In FIG. 33, time T1 indicates a state in which the buffer paper pressing solenoid SL3 is ON and the rear end pressing 135 is separated from the transport surface of the lower transport guide plate 123b. Time T2 indicates a state in which the buffer paper pressing solenoid SL3 is turned off and the rear end pressing 135 is rotating to a position where it is pressed against the conveyance surface of the lower conveyance guide plate 123b.

  The point z on the right side of the time T2 indicates that the rear end press 135 is pressed against the conveyance surface of the lower conveyance guide plate 123b. Time T3 indicates that the ON duty control is performed on the buffer paper pressing solenoid SL3.

  On the other hand, as shown in the lower diagram of FIG. 33, in the conventional control, no control is entered during the time T2, and the rear end presser 135 has its own weight and the above-mentioned weight of the rear end presser 135 itself. Since the compression force of the holding spring 180 that generated a large compression force collided with the conveyance surface of the lower conveyance guide plate 123b, a large collision sound and vibration were generated.

  In contrast, in this embodiment, by performing ON duty control during the time T2, the rear end presser 135 is once returned to the separating direction immediately before the rear end presser 135 is pressed against the lower conveyance guide 123b. Therefore, the collision force when colliding with the conveyance surface can be reduced. Thereby, the collision sound at that time can be greatly reduced. In the ON duty control of about 10 ms, the buffer paper pressing solenoid SL3 body does not generate an attractive force enough to re-suck the solenoid 182 even if an excitation current flows, and the moving force is reduced. Since this is a control, no problem occurs in the sheet holding operation.

  In addition, when ON duty control is performed during T2, the timing can be arbitrarily set. Further, the number of times is not limited to one, and it can be the same or more than several times. The effect of can be demonstrated.

  Further, the operation of the buffer paper pressing solenoid SL3 performed during the time T2 may be performed by lowering the energization voltage than when the rear end pressing 135 is separated.

  In the sheet staying device of this embodiment, when the buffer paper pressing solenoid SL3 is turned off, the trailing edge press 135 accelerated by the pressing spring 180 collides with the lower conveyance guide 123b and the sheet surface, but the acceleration of the trailing edge press 135 advances. Immediately before the collision, the buffer paper pressing solenoid SL3 is turned ON again to decelerate the trailing edge pressing 135, thereby reducing the impact of the collision. The excitation force to the can be suppressed.

  Since the impact of the collision of the rear end presser 135 is reduced by operating the buffer paper presser solenoid SL3 in a limited manner, the mechanism and control circuit for operating the buffer paper presser solenoid SL3 to separate the rear end presser 135 are used as they are. The above-mentioned problems can be solved by using this.

  Furthermore, since the buffer paper pressing solenoid SL3 is energized once or more for a short time, it is not necessary to control the energizing voltage, there is no increase in power consumption due to the voltage change, and a small amount of the existing ON / OFF element control program. The above-mentioned problems can be solved only by the change.

  In any case, the strong pressing spring 180 is used to resist the frictional force with the subsequent sheets (P2, P3) conveyed to the buffer roller 124, and the sheet P1 is displaced or dropped from being caught. Noise and vibration can be reduced while sufficiently blocking, without adding new parts, soundproofing structure and silencer to the sheet retention device shown in Patent Document 1, and without impairing sheet retention and conveyance quality , Noise and vibration can be suppressed, and the sheet processing device incorporating the sheet retention device can be made quieter, lower vibration, improved reliability by reducing vibration, and improved durability. This can contribute to further downsizing and higher performance of the forming apparatus.

  More specifically, when the sheet P1 is held by the trailing edge press 135, the buffer P may cause a force to be pulled out from the trailing edge press 135 by the buffer roller 124, so that the force is not lost. Therefore, conventionally, the force for holding the sheet P1 is increased by increasing the force of the coil spring 180. In that case, there has been a problem that the collision sound generated when the rear end press 135 is pressed against the lower conveyance guide 123b becomes very loud. As countermeasures against this noise, a damper is added to absorb the impact of the collision of the rear end presser 135, and a stepping motor and a torque limiter are used so that the position / contact of the rear end presser 135 can be finely controlled. There is something to replace with the mechanism that was, but this leads to a considerable cost increase.

  However, in the sheet processing apparatus of this embodiment, in order to reduce the collision when the rear end presser 135 is pressed against the conveyance surface, an additional damper that increases the cost or a mechanism using a stepping motor or the like is used. By using the driving of the buffer paper pressing solenoid SL3 for separating the rear end presser 135 during the operation in which the rear end presser 135 tries to press-contact, the collision is mitigated. As a result, the rear end presser 135 is It is possible to reduce the collision sound that occurs when being pressed.

  According to the sheet processing apparatus of the first embodiment, when the previous sheet bundle performs the post-processing operation on the processing tray 129, the subsequent sheets P1, P2, and P3 are not conveyed to the processing tray 129 being processed. Thus, it is possible to effectively reduce the noise and vibration of the sheet conveyance standby mechanism constituted by the rear end press 135, the buffer paper press solenoid SL3, and the like, which are held in the upper limit without causing an increase in cost and an increase in size.

(Sheet sorting device)
FIG. 34 is a front view of a sheet sorting apparatus that switches the sheet conveyance path. The sheet sorting apparatus according to this embodiment includes a flapper solenoid SL4 that is a drive element, a flapper 122 that is a flapper member, a coil spring 190 that is an urging unit, and a finisher control unit 211 that is a control unit, for example. .

  The present invention can be used not only for the buffer unit 140 described above, but also for other mechanisms that actuate the solenoid against the spring. For example, as shown in FIG. 34, the present invention can be applied to a sheet sorting apparatus using a flapper. As shown in FIG. 4, the sheet sorting apparatus is located upstream of the sheet conveyance standby mechanism (buffer unit 140 and the like), operates the flapper 122, and determines the conveyance destination of the sheet sent from the apparatus main body 101. Switch between unit and copy unit.

  As shown in FIG. 34, the flapper 122 is supported so as to be pivotable about a shaft 193, and the pivot end 122a is pivoted up and down to move the transport path R1 in the horizontal direction of the sheet P1 to the lower transport path. Switching to R2 or vice versa is possible. A coil spring 190 is attached to one end side of the arm 191 that rotates integrally with the flapper 122, and the coil spring 190 biases the flapper in a direction to rotate downward via the arm 191.

  The plunger 192 of the flapper solenoid SL4 is connected to the other end side of the arm 191. When energization of the flapper solenoid SL4 is turned on, the plunger 192 is drawn into the main body of the flapper solenoid SL4 and the arm 191 is moved against the coil spring 194. The rotation end 122a of the flapper 122 is rotated upward.

  The flapper solenoid 122 is also subjected to ON duty control as shown in FIG. 33 to reduce noise and vibration during operation of the flapper solenoid 122.

  That is, during the period from when the flapper solenoid 122 is turned on and the conveyance path R2 is opened to when the flapper solenoid 122 is turned off and the rotating end 122a is stopped, the flapper solenoid 122 is turned on at least once for 10 msec, for example. The flapper 122 is decelerated, the operation sound of the flapper solenoid and the impact when the flapper 122 stops suddenly are weakened, and the same effect as that of the rear end press 135 (FIG. 31) is obtained.

  In this embodiment, the copying machine 100 is exemplified as the image forming apparatus. However, the sheet staying apparatus and the sheet sorting apparatus of the present invention are limited to the copying machine 100, the sheet processing apparatus 119, and the described installation location. It accepts sheets carried out from image forming apparatuses such as copiers, printers, facsimiles, and office machines, and aligns, sorts, stacks, staples, folding, envelope packing, binding processing, bookbinding, punching, inspection, By applying the present invention equally to a sheet processing apparatus that performs various processes such as processing, noise and vibration when the solenoid is turned off in a mechanism that operates the solenoid against the spring can be equally reduced.

  The copying machine 100 may have not only a function as a simple copying machine but also a function as a network printer shared by many users. The CPU circuit unit 200 and the finisher control unit 211 in FIG. It may be configured.

  In the present exemplary embodiment, the sheet processing apparatus that is detachable from the image forming apparatus is illustrated. However, the present invention is stored in the housing of the image forming apparatus and controlled by the control circuit of the image forming apparatus. A built-in sheet processing apparatus may be used, and the same effect can be obtained by applying the present invention to such a sheet material processing apparatus.

  In this embodiment, the electrophotographic method is exemplified as the recording method. However, the present invention is not limited to this, and other recording methods such as an ink jet method may be used.

  In the present embodiment, the stapler 132 is illustrated as an example for creating a sheet bundle inside the finisher of the sheet processing apparatus 119. However, the present invention is not limited to this. For example, a sheet bundle such as a glue binding mechanism is used. It may be a creation device.

1 is an explanatory diagram of an image forming apparatus to which a sheet processing apparatus according to an exemplary embodiment is mounted. 2 is a block diagram of a control system of the image forming apparatus. FIG. It is explanatory drawing of a structure of a sheet processing apparatus. FIG. 6 is an explanatory diagram of a drive system for a sheet conveyance path. It is explanatory drawing of operation | movement of rear-end assistance. It is explanatory drawing of operation | movement of rear-end assistance. It is explanatory drawing of operation | movement of rear-end assistance. It is a block diagram of a control system of the sheet processing apparatus. It is a flowchart of sheet discharge control. It is a diagram of the conveyance speed of a rear end assist and a swing roller pair. It is a diagram of the conveyance speed of rear end assist. It is a diagram of the conveyance speed of an entrance conveyance motor. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. FIG. 10 is an explanatory diagram of sheet conveyance in post-processing that does not buffer sheets. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is explanatory drawing of the sheet conveyance in the post-processing performed by buffering a sheet. It is the perspective view which showed the structure and drive of the rocking roller mechanism. FIG. 6 is a front view of a sheet conveyance standby mechanism that performs a sheet holding operation. FIG. 6 is a front view of a sheet conveyance standby mechanism that performs a sheet holding operation. It is explanatory drawing of ON duty control of the buffer paper pressing solenoid SL3. FIG. 6 is a front view of a sheet sorting apparatus that switches a sheet conveyance path.

Explanation of symbols

SL3 Buffer paper holding solenoid (drive element)
SL4 flapper solenoid (drive element)
M2 inlet conveyance motor M3 bundling motor 100 copier (image forming apparatus)
101 apparatus main body 114 photosensitive drum (image forming means)
119 Sheet processing device 122 Flapper (contact member)
123b Lower conveyance guide 124 Buffer roller 126 First paper discharge roller pair 127 Swing roller pair 128 Stack tray (sheet stacking means)
129 Processing tray 132 Stapler 135 Rear end presser (contact member)
140 Buffer unit 141 Friction member 180 Pressing spring 181 Rear end pressing arm 182, 192 Plunger 211 Finisher control unit (control means)
180 Pressing spring (biasing means)
181 Rear end holding arm 182 Plunger 190 Coil spring (biasing means)
191 Arm

Claims (8)

A contact member disposed so as to be able to contact the support surface of the sheet conveyance path;
A biasing member that biases the abutting member toward the support surface;
A drive element for driving the contact member in a direction away from the support surface,
In the sheet retention device that sandwiches the sheet between the support surface and the contact member and retains the sheet in the conveyance path,
The drive element is decelerated by the drive element during a period from when the drive element is released until the contact member comes into contact with the support surface, and when the contact member comes into contact with the support surface. A sheet retention device that reduces impact. A contact member disposed so as to be able to contact the support surface of the sheet conveyance path;
A biasing member that biases the abutting member toward the support surface;
A drive element for driving the contact member in a direction away from the support surface;
A conveying member that is disposed downstream of the contact member and can convey the sheet in both forward and reverse directions of the conveying path;
After the conveying member is operated in the forward direction to convey the sheet to the downstream side of the contact member, the driving element is operated to form a gap between the support surface and the contact member. A control unit that releases the operation of the driving element after the conveying member is operated in the reverse direction to convey the sheet to the gap;
The control means operates the drive element in a limited manner during a period from when the operation of the drive element is released until the contact member contacts the support surface, so that the contact member contacts the support surface. A sheet staying device characterized by being a means for alleviating an impact at the time of contact.   The said control means performs short-time electricity supply to the said drive element 1 time or more in the period until it stops the electricity supply to the said drive element, and the said contact member contact | abuts to the said support surface. 2. The sheet retention device according to 2. The contact member is pivotally supported adjacent to the transport path,
4. The sheet staying device according to claim 1, wherein the driving element and the biasing member are connected to an arm member fixed to the contact member. 5. An inlet conveying member that conveys the sheet and receives it in the conveying path;
A sheet retention device according to any one of claims 1 to 4,
A sheet processing apparatus comprising: a sheet stacking member on which the sheets transported along the transport path are stacked. A flapper member rotatably disposed at a branch point of the sheet conveyance path;
A biasing member that biases the flapper member in one rotational direction;
A driving element that drives the flapper member against the biasing member to rotate in the reverse direction;
In a sheet distribution apparatus comprising: a control unit that operates the driving element to switch the sheet conveyance path;
The control means operates the drive element in a limited manner during a period until the flapper member completes switching of the transport path after releasing the operation of the drive element, and the flapper member switches the transport path. A sheet sorting apparatus characterized by being a means for reducing the impact of the sheet. A sheet sorting apparatus according to claim 6,
A stitcher unit that staples one end of the sheet is arranged in one conveyance path branched by the flapper member, and a bookbinding unit that arranges the center of the sheet in two stitches and folds in two is arranged in the other conveyance path. A sheet processing apparatus. Image forming means for forming an image on the sheet;
An image forming apparatus comprising: a sheet processing unit that receives and processes the sheet image-formed by the image forming unit;
8. An image forming apparatus according to claim 5, wherein the sheet processing unit is the sheet processing apparatus according to claim 5.

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