JP2006082923A - Sheet treatment device and image formation device provided with this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet treatment device and an image formation device provided with this capable of standing-by and retaining a sheet without performing switch back. <P>SOLUTION: An adsorption stand-by means 3 is provided in an upstream of a sheet loading part 14 for loading the sheets S1 to be treated and at least one sheet of sheet S1 subsequently treated is sucked and stood-by by the suction stand-by means 3 during when the sheet on the sheet loading part is treated. The sheet S1 can be stood-by/retained without performing switchback. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet processing apparatus and an image forming apparatus including the sheet processing apparatus, and more particularly, to a sheet processing apparatus that waits for a next sheet to be processed while the sheet is being processed.

  In recent years, an image forming apparatus such as an electrophotographic copying machine or a laser beam printer optionally includes a sheet processing apparatus that performs processing such as sorting on an image-formed sheet discharged from the image forming apparatus main body. There is. Such a sheet processing apparatus performs not only sorting but also various processing such as stacking and alignment of a plurality of sheets, and staple binding using a stapler.

  By the way, in a sheet processing apparatus equipped with a stapler, for example, when binding processing is performed, after an image is formed, the sheet conveyed into the sheet processing apparatus main body passes through a conveyance path formed inside the main body. Thus, after the sheets are stacked on the processing tray, the binding operation is performed. When binding a bundle of sheets, a stapler that is a binding unit is moved to perform one-point binding or plural binding (usually two-point binding).

  Here, while a job of such a binding operation (binding process) is being performed, the sheet of the next job cannot be stacked on the processing tray. Was common. However, if the gap between the jobs is made in this way, the productivity is lowered.

  Therefore, in order to prevent such a decrease in productivity, for example, while a sheet is being processed on the processing tray, the sheet to be processed next is not conveyed to the processing tray, but is placed on the upstream side of the processing tray. There is something like that (see Patent Document 1).

  For example, FIG. 10 is a diagram showing the configuration of such a conventional sheet processing apparatus, and FIG. 10A shows a binding process using a stapler (not shown) for the sheet bundle 52 stacked on the processing tray 51. The state which is going to give is shown. In this state, when the first sheet 53 of the next job is conveyed into the finisher by the entrance roller 54, the sheet 53 is first rotated in the direction of the arrow of the buffer roller 50 which can be rotated forward and backward. Thus, the sheet is conveyed downstream of the buffer guide 55.

  Next, when the sheet 53 is conveyed downstream by a predetermined amount x (switchback point) from the buffer guide 55, the buffer roller 50 reverses in the direction of the arrow shown in FIG. Switched back (reverse feed) and hits the buffer guide 55. Then, after the sheet 53 hits in this way, the buffer guide 55 is rotated in the direction of the arrow by a solenoid or the like (not shown) to hold the rear end portion of the sheet 53. As a result, the sheet 53 waits at this position.

JP 2003-081517 A

  However, in the conventional sheet processing apparatus having such a configuration, the conveyed sheet 53 is stopped once every time and then switched back, so that jamming is likely to occur and the switchback operation is performed. Since time is required, there is a problem that the number of processed sheets per unit time is small and productivity is lowered.

  Further, at the time of switchback by the buffer roller 55, an image defect may occur due to rubbing between a guide plate (not shown) and the sheet at a point indicated by A provided below the buffer roller 55. Further, the switched back sheet may be abutted against the buffer guide 55, so that the end portion may be damaged.

  In addition, since the sheet 53 immediately after image formation is generally in a high temperature state, when the sheet 53 is put on standby, the surrounding guides holding the sheet 53 become high temperature. The operability at the time has deteriorated, and the durability of the buffer guide holding portion has been problematic.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet processing apparatus capable of storing sheets without switching back and an image forming apparatus including the sheet processing apparatus. It is.

  The present invention provides a sheet processing apparatus that processes a sheet after stacking the sheet on which an image is formed, and a sheet stacking unit that stacks the sheet to be processed, upstream of the sheet stacking unit. And a suction standby unit that sucks and waits for at least one sheet to be processed next while the sheets on the sheet stacking unit are being processed.

  By sucking and waiting at least one sheet to be processed next while the sheets on the sheet stacking unit are processed by the suction standby unit provided upstream of the sheet stacking unit as in the present invention, The sheet can be held on standby without being switched back.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus provided with a sheet processing apparatus according to an embodiment of the present invention. In FIG. 1, 100 is an image forming apparatus, and 100A is an image forming apparatus main body (hereinafter referred to as an apparatus). 19 is a sheet processing apparatus that processes the image-formed sheet discharged from the apparatus main body 100A. In the present embodiment, the sheet processing apparatus (hereinafter referred to as finisher) 19 is an independent apparatus that is detachably attached to the apparatus main body 100A as an option, but is integrally provided in the apparatus main body 100A. Needless to say, this also applies to the case where it is applied.

  Here, the apparatus main body 100A is provided with an image forming unit 100B and a sheet feeding unit 100C for feeding sheets such as plastic films accommodated in the cassette 115A to the image forming unit 100B. An automatic document feeder 102 is provided on the upper part of the apparatus main body 100A.

  In the image forming apparatus 100 having such a configuration, when an image is formed on a sheet, first, in the automatic document feeder 102, the document G placed on the document placing unit 103 is fed by the feeding unit 104. After sequentially separating the sheets one by one, the skew feeding is corrected by the registration roller pair 105, and then the reading position 107 is passed through the introduction path 106. Then, the reflected light obtained by irradiating the original G passing through the reading position 107 with light by the illumination system 111 is guided to the optical element 113 (CCD or other element) by the mirror 112. Then, the image formed on the surface of the original is read to obtain image data.

  When the document passes through the reading position 107, the document on which the image has been read passes through the discharge path 108 and is then discharged onto the discharge tray 109. In the case of reading both the front and back surfaces, after the image of the front surface is read in this way, the original G passes through the discharge path 108, and then is reversed again by the reversing roller pair 110 and then the registration roller pair 105 again. Sent to.

  After that, the original G is formed on the front surface (in this case, the back surface) at the reading position 107 after passing through the introduction path 106 after the skew is corrected by the registration roller pair 105 in the same manner as the front surface reading. The image is read. Then, after the back side image is read in this way, the document G passes through the discharge path 108 and is discharged to the discharge tray 109.

  On the other hand, in the image forming unit 100B, laser light is irradiated to the photosensitive drum 114 from an exposure unit (not shown) based on the obtained image data, thereby forming a latent image on the surface of the photosensitive drum 114. The mirror 112 may be configured to directly irradiate the photosensitive drum 114 with reflected light to form a latent image.

  Next, the latent image formed on the photosensitive drum 114 in this manner is further developed with toner supplied from a toner supply device (not shown), thereby forming a toner image on the photosensitive drum.

  In parallel with such an image forming operation, in the paper feeding unit 100C, the sheet stored in the cassette 115A is supplied to a position facing the photosensitive drum 114 in accordance with a recording signal. The toner image formed on the photosensitive drum 114 is transferred by the transfer device 116. Then, the sheet on which the toner image is transferred is sent to the fixing device 117, and the image is permanently fixed on the sheet by being pressurized and heated in the fixing device 117.

  When forming images on both sides of the sheet, the sheet on which the image is fixed on one side by the fixing device 117 in this way passes again through the double-sided path 118 provided on the downstream side of the fixing device 117, and then the photosensitive drum. 114 and the transfer device 116. As a result, a toner image is also formed on the back surface of the sheet. Then, the sheet on which the image is formed on one side or both sides in this way is discharged to the outside (finisher 19 side) by the paper discharge roller 121.

  FIG. 2 is a diagram showing the configuration of the finisher 19. In FIG. 2, reference numerals 1A and 1B denote a pair of inlet rollers, and 15 denotes a leading end of a sheet guided to a conveyance path 2 which is a sheet conveyance path provided inside the finisher. A sensor 4 which is a detecting means for detecting is a buffer roller, and the buffer roller 4 is rotated in the vertical direction with the axis B as a fulcrum.

  5A is an upper discharge roller, 5B is a lower discharge roller, 7A is an upper bundle discharge roller, 7B is a lower bundle discharge roller, and 6 is a rotatable upper discharge roller 5A and upper bundle discharge roller 7A. A holder that can be held and moved in the vertical direction. Reference numeral 6A denotes a push-up member, and the holder 6 is moved upward by the push-up member 6A. When the holder 6 moves upward in this way, the upper discharge roller 5A and the upper bundle discharge roller 7A are respectively moved. The lower discharge roller 5B and the lower bundle discharge roller 7B are separated from each other.

  Reference numeral 13 denotes a stepped portion provided upstream of the transport path 2 (downstream of the inlet roller pair 1A, 1B), and a suction fan 3 serving as a suction standby unit is provided below the stepped portion 13. . Then, as will be described later, when the suction fan 3 is driven after the trailing end of the sheet S1 reaches above the stepped portion 13 and stops, the trailing end of the sheet S1 becomes the inclined surface 13a of the stepped portion 13. And it is adsorbed while curving along the bottom surface 13b.

  In FIG. 2, 10 is a stack tray on which sheets discharged by the bundle discharge roller pairs 7A and 7B that can be rotated in the forward and reverse directions, and 14 is inclined downward from the bundle discharge roller pair side for processing. A processing tray 9 serving as a sheet stacking unit on which sheets are stacked is a stapler that binds a bundle of sheets stacked on the processing tray 14.

  A rear end stopper 12 is provided on the inclined end side of the processing tray 14 and abuts against a sheet sliding down along the processing tray 14, and the rear end stopper 12 is fixed to the belt 12a. Reference numeral 11 denotes a drive motor that rotates the belt 12a. After the binding process of the sheet bundle stacked on the processing tray 14 is completed, the belt 12a is rotated by the drive motor 11 so that the trailing end stopper 12 is moved to the stack tray side. To move to. The bound sheet bundle is discharged onto the stack tray 10 by moving the trailing end stopper 12 in this way.

  Reference numeral 8 denotes a return roller. By this return roller 8, the sheets stacked on the processing tray are returned to the trailing edge stopper side by rotation in the direction opposite to the arrow direction of the bundle discharge roller pair 7A, 7B, and are stapled. The rear end position at the time of being performed is regulated by the rear end stopper 12.

  Then, a predetermined number of sheets are abutted against the rear end stopper 12 by the forward / reverse rotation of the pair of bundle discharge rollers 7A and 7B and the return roller 8 to form a sheet bundle on the processing tray, and then the stapler 9 is driven. Thus, the binding process is performed on the sheet bundle. After such a binding operation is finished, the bundled sheet discharge roller pair 7A, 7B is rotated in the direction of the arrow, and the trailing edge stopper 12 is moved so that the bound sheet bundle is discharged to the stack tray 10. Is done.

  By the way, when the first sheet S1 of the next job is discharged from the apparatus main body 1 while the sheet is being processed in this way, the sheet S1 is first supplied to the finisher entrance roller pair 1A, as shown in FIG. After being guided to the transport path 2 inside the finisher by 1B, the tip of the sensor 15 is detected. Based on the detection signal from the sensor 15, a control unit (not shown) thereafter drives the buffer roller 4 and the pair of paper discharge rollers 5A and 5B so as to convey the sheet S1 to a predetermined position. .

  Next, as shown in FIG. 3, the sheet S1 is transferred to the bundle discharge roller pair 7A, 7B rotating in the direction of the arrow, and the leading end of the sheet S1 is placed on the stack tray 10 by the bundle discharge roller pair 7A, 7B. To be loaded. After that, when the trailing end of the sheet S1 reaches above the step portion 13, the control unit causes the buffer roller 4, the discharge roller pairs 5A and 5B, and the bundle discharge roller pair 7A, which constitute the sheet conveying means. 7B is stopped and the suction fan 3 is driven. As a result, as shown in FIG. 4, the sheet S <b> 1 is adsorbed while being curved along the inclined surface 13 a and the bottom surface 13 b of the step portion 13.

  Here, in the present embodiment, the stepped portion 13 has a depth that does not come into contact with the rear end portion of the attracted sheet S1 when the sheet S2 to be conveyed next enters the conveyance path 2 as will be described later. Have Therefore, when the rear end portion of the sheet S1 is sucked and held on the step portion 13 having such a depth, the second sheet S2 newly conveyed to the rear end portion of the temporarily retained sheet S1. The tip of is not caught. The sheet S1 discharged from the apparatus main body 1 normally passes through the fixing device 17 and is in a high temperature state. However, when it is sucked by the suction fan 3, the sheet S1 is effectively cooled and conveyed. The transport guide 2a and the like in pass 2 do not become hot.

  Next, after the sheet S1 is sucked and held in this way, as shown in FIG. 5, the push-up member 6A is rotated upward with the axis C as a fulcrum by a driving means (not shown). When the push-up member 6A is rotated upward in this manner, the holder 6 is rotated upward with the axis D as a fulcrum, and accordingly, the upper discharge roller 5A and the upper bundle discharge roller 7A are respectively set to the lower discharge roller 5B. And the lower bundle delivery roller 7B. As a result, the paper discharge roller pair 5A, 5B and the bundle paper discharge roller pair 7A, 7B do not exert a conveying force on the temporarily retained sheet S1.

  In this state, when the second sheet S2 is conveyed from the apparatus main body 1 as shown in FIG. 5, the sheet S2 is conveyed by the pair of inlet rollers 1A and 1B, and then the leading edge of the sheet S2 is moved. After the detection by the sensor 15 and the trailing edge of the sheet S2 passes through the pair of entrance rollers 1A and 1B, the sheet S2 is conveyed by the buffer roller 4.

  Here, the first sheet S1 temporarily retained at this time is subjected to a conveying force having a value obtained by multiplying the pressure applied by the buffer roller 4 and the friction coefficient between the two sheets S1 and S2. Since the suction force of the suction fan 3 is set to be larger than the conveying force, the first sheet S1 is not carried along by the second sheet S2. As a result, only the second sheet S <b> 2 is conveyed by the buffer roller 4. The sheet S2 is transported and controlled by a control unit (not shown) until the rear end portion is positioned above the rear end portion of the sucked sheet S1.

  Next, when the rear end portion of the second sheet S2 reaches a position above the rear end portion of the first sheet S1 as shown in FIG. 6, the buffer roller 4 is supported by a driving means such as a solenoid (not shown) as a fulcrum B. , The second sheet S2 is stopped, and then the push-up member 6A is rotated downward with the axis C as a fulcrum, and the holder 6 is rotated downward with the axis D as a fulcrum.

  As a result, the upper sheet discharge roller 5A and the upper bundle sheet discharge roller 7A sandwich the two sheets S1 and S2 together with the lower sheet discharge roller 5B and the lower bundle sheet discharge roller 7B, respectively. When the roller 5B and the lower bundle discharge roller 7B are rotated, the temporarily retained first sheet S1 and the second sheet S2 are conveyed.

  Next, when the two sheets S1, S2 pass through the paper discharge roller pair 5A, 5B, and then the bundle paper discharge roller pair 7A, 7B rotates in the reverse direction, the two sheets S1, S2 are placed on the processing tray 14. 7 and is abutted against the rear end stopper 12 by the return roller 8 as shown in FIG. After that, the sheets are conveyed one by one from the apparatus main body 1 to the finisher 19 one after another, and when the number of sheets stacked on the processing tray reaches a predetermined number, the stapler 9 binds the sheet bundle in the processing tray. Apply.

  After the binding process is completed in this way, the drive belt 12a is driven by the drive motor 11, whereby the rear end stopper 12 moves to the bundle discharge roller opposite side, and the rear end stopper 12 and the bundle discharge The bound sheets are bundled and discharged onto the stack tray 10 by the pair of paper rollers 7A and 7B. During the binding process of the second sheet bundle, the first sheet of the next job (third copy) is conveyed to the conveyance path 2, and this sheet is illustrated in FIGS. As shown in FIG.

  In this way, while the sheet on the processing tray is being processed by the suction fan 3, the sheet is held on standby without being switched back by sucking and waiting at least one sheet to be processed next. Can do. In this way, by enabling the sheet to be held on standby without switching back, it is possible to achieve high productivity while ensuring jam reduction.

  In addition, image rubbing and scratches that have occurred during the switchback operation are eliminated, whereby a high-quality sheet can be provided. Furthermore, by using the suction fan 3, it is possible to cool the buffer portion including the step portion 13 that waits for a high-temperature sheet by air, thereby not only solving the problem regarding the durability of the buffer portion, It is possible to prevent a decrease in jam handling performance.

  By the way, in the description so far, the control for detecting the leading edge of the sheet by the sensor 15 and stopping the sheet at a predetermined position has been described. However, after the sensor 15 detects the trailing edge of the sheet, The same effect can be obtained even if control for conveying a predetermined amount is performed.

  In the description so far, the case where the number of sheets temporarily retained is one has been described. However, the number of sheets temporarily retained is not limited to this, and as shown in FIG. By stacking the trailing ends of the sheet S1 and the second sheet S2 in a tiled shape with a phase difference of E, a plurality of sheets can be temporarily retained even in the case of air adsorption. When a plurality of sheets are stacked in a tiled manner as described above, for example, the stop position of the second sheet S2 is set on the upstream side in the sheet conveyance direction with respect to the first sheet S1. It may be controlled to. That is, since the rear end portion of the sheet S2 protrudes upstream of the rear end portion of the sheet S1 by the phase difference E in the sheet conveying direction, the rear end portion of the sheet S2 is directly adsorbed by the adsorbing fan 3 to secure the adsorbing force.

  Furthermore, in the description so far, the method of adsorbing the rear end portion of the sheet by the adsorption fan 3 (adsorption means) has been described, but the adsorption method is not limited to this, the sheet front end portion, In some cases, the entire sheet may be adsorbed. In other words, the same effect can be obtained if the adsorbed sheet can secure an adsorbing force sufficient to prevent the adsorbed sheet from being conveyed by the frictional force with the new sheet.

  By the way, although the suction method using air by the suction fan 3 has been described so far, the present invention is not limited to this. For example, as shown in FIG. May be adsorbed by static electricity.

  Here, in the case of such electrostatic adsorption, since the adsorption force due to static electricity works through the sheet, there is no need to stack the sheet S as described with reference to FIG. 8, and a plurality of sheets with the sheet rear end aligned. The sheet can be temporarily retained. In the case of such electrostatic adsorption, there is a possibility that high-speed adsorption such as air may not be possible. Therefore, the finisher 19 is connected to a so-called high-productivity image forming apparatus in which the time between sheets is short. 9, for example, as shown in FIG. 9, air is ejected from above to the electrostatic adsorption means 20 side, and the air is urged toward the electrostatic adsorption means 20 by this air to assist the buffer operation. Preferably it is done.

  By the way, in the adsorption method using air or static electricity described so far, it can be easily predicted that the necessary adsorption force varies depending on the size, type, weight, etc. of the temporarily retained sheet. Therefore, the suction force may be set so as to satisfy all the temporarily retained sheets. However, in order to reduce power consumption and noise, for example, by the control unit, the sheet size, type, It is preferable that the suction force be controlled according to at least one of the weight and the like.

  Further, the suction means need not be limited to the air suction means and the electrostatic suction means described here, and the same effect can be obtained as long as it can control whether or not the sheet is sucked. It goes without saying that you can do things. Further, in the above description, the stepped portion 13 is provided below the upstream side of the conveyance path 2. However, the present invention is not limited to this, and the conveyance path 2 is not limited to this, as long as the conveyance of the next sheet is not hindered. The suction standby means may be provided above the step portion 13 and provided above the upstream side.

1 is a diagram illustrating a schematic configuration of an image forming apparatus including a sheet processing apparatus (finisher) according to an embodiment of the present invention. FIG. 3 is a first diagram illustrating a schematic configuration and a buffer operation of the sheet processing apparatus. FIG. 6 is a second diagram illustrating a buffer operation in the sheet processing apparatus. FIG. 10 is a third diagram illustrating a buffer operation in the sheet processing apparatus. FIG. 10 is a fourth diagram illustrating a buffer operation in the sheet processing apparatus. FIG. 10 is a fifth diagram illustrating a buffer operation in the sheet processing apparatus. FIG. 6 is a sixth diagram illustrating a buffer operation in the sheet processing apparatus. The figure which shows a mode that the several sheet | seat was loaded in the tile stack in the said sheet processing apparatus. The figure explaining the other structure of the said sheet processing apparatus. FIG. 10 is a diagram illustrating a buffer operation of a conventional sheet processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 1A Image forming apparatus 1B Image forming part 2 Conveyance path 3 Adsorption fan 4 Buffer roller 5A, 5B Paper discharge roller pair 7A, 7B Bundle paper discharge roller pair 13 Step part 14 Processing tray 15 Sensor 19 Sheet processing apparatus ( Finisher)
20 Electrostatic adsorption means S1 First sheet S2 Second sheet

Claims (10)

In a sheet processing apparatus that performs processing on the sheet after stacking sheets on which images are formed,
A sheet stacking unit for stacking sheets to be subjected to the processing;
An adsorption standby unit that is arranged upstream of the sheet stacking unit and sucks and waits for at least one sheet to be processed next while a sheet on the sheet stacking unit is being processed;
A sheet processing apparatus comprising:   The sheet processing according to claim 1, wherein a step portion is provided in an upstream portion of a sheet conveyance path for conveying the sheet to be processed to the sheet stacking portion, and the suction standby unit is provided in the step portion. apparatus.   The sheet processing apparatus according to claim 2, wherein the suction standby unit sucks a rear end portion of at least one sheet to be processed next along a sheet stacking surface of the stepped portion.   The step portion has a depth that does not come into contact with a rear end portion of the sucked sheet when the next sheet of the sucked sheet enters the sheet conveyance path. The sheet processing apparatus according to claim 2 or 3. Detecting means for detecting a sheet to be subjected to the processing;
Sheet conveying means provided in the sheet conveying path;
Control means for controlling driving of the sheet conveying means;
With
The control means controls the sheet conveying means to stop a rear end portion of at least one sheet to be processed next at a position facing the suction standby means in response to a signal from the detection means. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is characterized.   The sheet processing apparatus according to claim 1, wherein the suction standby unit sucks the sheet by air suction.   The sheet processing apparatus according to claim 1, wherein the adsorption standby unit adsorbs the sheet by electrostatic adsorption.   8. The sheet processing apparatus according to claim 6, wherein when the plurality of sheets are sucked, the suction standby unit sucks the sheets in a tiled state.   The sheet processing apparatus according to claim 1, wherein the suction force of the suction standby unit is controlled according to at least one of a material, a size, and a weight of the sheet. An image forming unit that forms an image on a sheet, and the sheet processing apparatus according to claim 1 that processes a sheet on which an image is formed by the image forming unit. Image forming apparatus.

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