JP2004123302A - Sheet treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfactorily perform high precision sheet treatment with a simple structure without reducing a treatment capacity (productivity, the possible number of sheets to be treated, etc.) for a sheet bundle in the sheet treatment for image output paper. <P>SOLUTION: In a sheet post treatment device equipped with a bundle carrying means carrying the sheet bundle from a first stacking means 38 to a second stacking means 24, the second stacking means 24 has two positions of a stacking position receiving the sheet bundle S from the first stacking means 38 and stacking it and a retracting position located below the stacking position, and the second stacking means 24 is reciprocated between the stacking position and the retracting position while stacking treatment is performed on the first stacking means 38. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet processing device. For example, an image-formed sheet discharged from an image forming apparatus main body such as a copying machine, a printing machine, a laser beam printer, etc., is sequentially taken into the apparatus, and the sheet stacking unit performs processing such as alignment, sorting, and binding of the sheet. The present invention relates to a sheet processing apparatus suitable for discharging and stacking on a sheet.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an apparatus for processing an image output sheet, a first sheet stacking unit (hereinafter, referred to as a sheet processing apparatus) aligns a black-and-white image output sheet and performs sheet processing (also referred to as post-processing) such as staple binding. Regarding apparatuses that combine a processing tray) and a second sheet stacking unit (hereinafter referred to as a stack tray) that receives and stacks a sheet bundle for each bundle, for example, a large number of apparatuses include a technique disclosed in Patent Document 1. Proposed and implemented.
[0003]
In recent years, as fields related to digital copiers and printing, colorization of booklet information such as catalogs and product manuals that have recently been on the market, or booklet image information such as distribution materials in offices and the like has been rapidly progressing. Also in such a booklet creation, a booklet mainly containing a black-and-white image and a color image, or an output form of only a color image are increasing from a booklet mainly composed of a black-and-white image.
[0004]
Therefore, a sheet processing function similar to that of a monochrome image sheet is required, and a sheet processing technique for a color image output sheet is required. Characteristics of the color image output paper include (1) a high toner sheet fixing temperature, (2) a high amount of sheet holding charge due to friction due to conveyance, and a high applied bias during image formation, and (3) an image sheet surface μ. It is known that the black-and-white image output paper has different characteristics, such as low image quality.
[0005]
As described in Patent Documents 2 and 3, a cooling fan is provided in the discharge section of the image forming apparatus, and a sheet To cool the sheet material, or to effectively provide static elimination needles in the paper discharge portion as disclosed in Patent Document 4 to improve the static electricity removing effect on the sheet surface, and so forth. Various sheet processing methods for paper have been devised so far.
[0006]
[Patent Document 1]
JP-A-2-144370
[Patent Document 2]
JP-A-2002-067417
[Patent Document 3]
JP-A-2002-082591
[Patent Document 4]
JP-A-6-61857
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional example, the static elimination and cooling are performed for each discharge sheet, and a plurality of sheets such as a sheet bundle are not supported. For this reason, for example, in a conventional processing mode using a two-stage tray configuration of a processing tray and a stack tray, during processing stacking on the processing tray, it is not possible to completely remove by static elimination for each sheet when discharging the processing tray, At the stage where a small amount of potential remaining on the sheet forms a sheet bundle, one is caused by the accumulated charge and the other is caused by the fusion and adhesion of the toner due to the heat storage effect of the fixing holding heat on the sheet surface. In the double-sided transfer mode for large-size paper such as LDR, the unprocessed leading end (leading end in the conveying direction) is attached to a stack tray or a sheet bundle already stacked on the stack tray, and sheets such as staple binding are used. After processing, when the sheet bundle is discharged from the processing tray to the stack tray, the bundle Good and, a phenomenon that disturbs the integrity push the already stacked paper had the potential to occur.
[0008]
This phenomenon is unlikely to occur if the stacking capacity on the stack tray is small as in the past.However, in recent years, when increasing the capacity and processing many sheets, it is necessary to maintain the stacking state of the sheet bundle. In addition, further improvement is desired against the collapse of the bundle, the falling of the sheet, and the like.
[0009]
Therefore, an object of the present invention is to satisfy high-precision sheet processing with a simple configuration without lowering the processing capacity (productivity, possible number of processed sheets, etc.) of a sheet bundle when sheet processing image output paper. An object of the present invention is to provide a technology that can be used.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is directed to a sheet processing apparatus including a bundle conveying unit configured to convey a bundle of sheets from a first stacking unit to a second stacking unit. Has two positions, a stacking position for receiving and stacking a sheet bundle from the first stacking unit and a retreat position located below the stacking position, and the second position during the stacking process on the first stacking unit. The loading means reciprocates between the loading position and the retreat position.
[0011]
According to a second aspect of the present invention, there is provided a first stacking unit for stacking sheets discharged from the image forming apparatus main body, a second stacking unit disposed downstream of the first stacking unit, and the first stacking unit. Aligning means for aligning the sheets stacked on the stacking means in a direction intersecting the sheet conveying direction; sheet bundle processing means for processing a sheet bundle stacked on the first stacking means; And a bundle conveying means for conveying the sheet bundle aligned by the first stacking means from the first stacking means to the second stacking means. And a retreat position located below the loading position, and the second loading means is connected to the loading position and the retreat position during the loading process on the first loading means. Reciprocate between It is obtained by said.
[0012]
According to the present invention, as described above, the second stacking unit reciprocates between the stacking position and the retracted position, thereby causing a discharge failure or stacking due to sticking of discharged sheets due to thermal melting of the toner or sheet charging. Defects can be prevented. This makes it possible to satisfy high-accuracy sheet processing with a simple configuration without reducing the processing capacity (productivity, possible number of processed sheets, and the like) of a sheet bundle when sheet processing image output paper.
[0013]
In the invention according to claim 3, the second stacking unit is configured to move from the retreat position until the sheet bundle stacked on the first stacking unit is started to be conveyed to the second stacking unit by the bundle conveying unit. The movement to the loading position has been completed.
[0014]
With this configuration, it is not necessary to wait for the bundle to be discharged from the first loading unit until the second loading unit returns to the loading position.
[0015]
According to a fourth aspect of the present invention, the second stacking unit has two positions: a stacking position for receiving and stacking the sheet bundle from the first stacking unit, and a retreat position located below the stacking position. Assuming that the length of the first stacking unit in the sheet conveyance direction is x and the length of the processing sheet in the conveyance direction is y, when the relationship between x and y satisfies y ≧ 2.5x, the first stacking unit is stacked on the first stacking unit. It is characterized in that the second loading means reciprocates between the loading position and the retreat position during the processing.
[0016]
With such a configuration, the amount of protrusion from the first stacking unit is small, and the sheet bundle has already been stacked on the unprocessed end (the leading end in the transport direction), the stack tray surface, or the stack tray. The second stacking means does not reciprocate for small-size paper having no contact surface with the upper surface of the sheet bundle.
[0017]
The invention according to claim 5, wherein the second stacking means is a stacking position and a retracted position located below the stacking position when the image forming surface of the sheet discharged from the image forming apparatus reaches both sides of the sheet. And the second loading means reciprocates between the loading position and the retreat position during the loading process on the first loading means.
[0018]
With this configuration, the upper surface of the already stacked sheet bundle on the second stacking unit and the lower surface of the sheet bundle on the first stacking unit do not have the same image forming surface in the single-sided image forming mode. And the second loading means is not reciprocated.
[0019]
According to a sixth aspect of the present invention, the image forming apparatus is a forming apparatus capable of forming a color or black-and-white image, and the second stacking unit is configured to output an image of a sheet discharged from the image forming apparatus in color output. Has two positions, a loading position and a retreat position located below the loading position, and the second loading means reciprocates between the loading position and the retreat position during loading processing on the first loading means. It is characterized by moving.
[0020]
With such a configuration, the charge amount is excessively large on the unprocessed end of the sheet bundle (the leading end in the transport direction) and the contact surface between the stack tray surface and the upper surface of the sheet bundle already stacked on the stack tray. The second stacking means is reciprocated only when forming a color image having a high sheet surface temperature.
[0021]
Note that when the number of sheets on which the sheets are not easily charged or the number of sheets stacked on the first stacking means (processing tray) is small, the edges in the sheet conveyance direction are unlikely to adhere to each other. The second stacking means (stack tray) is not moved up and down.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 1 is a longitudinal sectional view showing a configuration of a main part of an image forming system apparatus to which the present invention is applied.
[0024]
The image forming sheet processing apparatus shown in FIG. 1 includes a black-and-white / color image forming apparatus main body 200 shown in FIGS. 2 and 3, a folding apparatus 400 shown in FIG. 4, and a finisher 600 having a processing section 500.
[0025]
FIG. 2 is a diagram showing the entire black-and-white / color image forming apparatus of the present invention, and FIG. 3 is a main sectional view of the black-and-white / color image forming apparatus of the present invention. The color image forming apparatus of the present invention will be described with reference to FIG. For example, photoconductor drums 201a (yellow), 201b (magenta), 201c (cyan), 201d (four parallel image forming media) that form toner images of respective colors of yellow, magenta, cyan, and black are formed. Black), and a transfer belt 221 as a transfer / conveying means disposed below the photosensitive drums 201a to 201d so as to extend longitudinally therethrough.
[0026]
Primary chargers 202a, 202b, 202c, 202d, developing devices 203a, 203b, 203c, 203d, and transfer chargers are respectively provided around photoreceptor drums 201a, 201b, 201c, 201d driven by an ultrasonic motor (not shown). Devices 204a, 204b, 204c, and 204d are arranged, and above the photosensitive drums 201a to 201d, exposure devices 206a, 206b, 206c, and 206d composed of LEDs and the like are arranged.
[0027]
The photosensitive drums 201a, 201b, 201c, and 201d are charged by chargers 202a, 202b, 202c, and 202d, respectively, and color-separated light images of yellow, magenta, cyan, and black are exposed to exposure devices 206a, 206b, 206c, and 206d. To form latent images of yellow, magenta, cyan, and black on the photosensitive drums 201a, 201b, 201c, and 201d. The latent images are developed by developing units 203a, 203b, 203c, and 203d. Yellow, magenta, cyan, and black toner images are sequentially formed on the body drums 201a, 201b, 201c, and 201d.
[0028]
Recording paper S, which is a transfer material, is stored in cassettes 207a to 207d. Each of the cassettes 207a to 207d has a configuration in which the cassette can be pulled out in the front direction in the drawing. For example, replenishment of recording paper and jam processing in the event of a jam in the cassette can be performed by pulling out the cassette to the front side of the apparatus. Has become.
[0029]
The recording paper S is sent out one by one from one of the cassettes 207a to 207d by the pickup rollers 208 (a to d), passes through the upper transport roller 209, is adjusted in timing by the registration roller 210, and is guided to the transport guide 218. Then, the transfer material is conveyed to a nip portion constituted by a pressing roller 212 as a pressing means for pressing the transfer material to the transfer conveying means and the transfer belt 221, and is conveyed on the transfer belt 221 in the direction A shown in FIG.
[0030]
A backup roller 217 is provided on the opposite side of the pressing roller 212 across the transfer belt 221. The pressing roller 212 is held by a pressing arm (not shown) and is pressed by a pressing spring (not shown). The recording sheet S pressed against the transfer belt 221 by the pressing roller 212 is sequentially conveyed to a transfer section facing each of the photosensitive drums 201a, 201b, 201c, and 201d by the rotation of the transfer belt 221, and is transferred to the photosensitive drums 201a, 201b, and 201d. The toner images of the respective colors on 201c and 201d are transferred onto the transfer material S in a superimposed manner by the action of the transfer blades 204a, 204b, 204c, and 204d, which are disposed in the respective transfer sections and have a voltage opposite in polarity to the toner, On the recording paper S, a color image in which four color toner images of yellow, magenta, cyan, and black are superimposed is obtained.
[0031]
The recording paper S onto which the four color toner images have been transferred is separated from the transfer belt 221 at the leading end in the transport direction and transported to the fixing device 211, where it is fixed by receiving heat and pressure, whereby the toner of each color is melted. After being mixed into a full-color print image fixed to the recording material S, the image is discharged outside the image recording apparatus by a sheet discharge conveyance unit 263 provided downstream of the fixing device 211.
[0032]
On the other hand, the sheet on which the image has been formed is conveyed to either the main body 1 of the sheet post-processing apparatus or a folding device (not shown) provided inside the mounting table 70 in accordance with the subsequent processing. . That is, when a sheet is processed by the main body 1 of the sheet post-processing apparatus, the upstream end of the first flapper 3 near the main body 200 of the copying machine shown in FIG. By locating the upstream end of the downstream second flapper 4 upward, the sheet is sent to the first transport path 6 by the roller pair 5 and further downstream from the first transport path 6. become.
[0033]
When the sheet is transported to the folding device, the upstream end of the first flapper 3 is positioned upward as shown in FIG. To the folding device located at the end of the
[0034]
In FIG. 4, 8 indicates a second transport path (buffer path), 9 indicates a buffer roller, 14, 15, and 16 indicate buffer rollers, and 10, 11, 12, and 13 indicate sheet detection sensors. ing. The sheet detection sensors 10, 11, 12, and 13 detect a passing sheet, a staying sheet, and the like.
[0035]
Reference numeral 17 denotes a first discharge roller, reference numeral 18 denotes a press roller, and reference numeral 19 denotes a discharge alignment belt. The discharge alignment belt 19 rotates while being sandwiched between the first discharge roller 17 and the press roller 18, and an endless rib (not shown) is provided near a central portion inside the belt as a measure for preventing the belt from coming off. It is adapted to rotate by engaging with the discharge roller 17.
[0036]
A belt roller 61 for moving the belt is disposed inside the discharge alignment belt 19. The discharge alignment belt 19 is swung by a belt moving plate 62 that reciprocates by a driving source (not shown). The belt moving plate 62 and the belt rollers 61 and 61a constitute moving means for forcibly deforming the discharge alignment belt 19 (see FIG. 12).
[0037]
The slanting shutter 34 is movable up and down, and when the tray unit 26 moves while loading the sheets, it rises and closes the hatched portion indicated by F in FIG. 7 to prevent the sheets from falling. When the sheet is discharged to the first tray 24, the sheet is moved below the second discharge roller 32 so as not to hinder the discharge of the sheet.
[0038]
In FIG. 4, the width shift plate 21 is adapted to perform sheet width alignment. Reference numeral 20 denotes an alignment butting member for regulating the rear end of the sheet. The aligning butting member 20 can take a home position when sheets are sequentially stacked on the processing tray 38 and a retracted position when the stapler (binding means) 22 moves back and forth. When the position of the stapler 22 is changed, the alignment butting member 20 having the same phase as that of the stapler 22 can rotate to the position shown by the broken line and retract.
[0039]
By the way, in the present embodiment, the alignment of the sheet in the width direction is performed by the width shift plate 21 shown in FIGS. Further, the stapler 22 performs stapling by moving in a range indicated by an arrow in FIG. 5 so that the sheet can be bound at two places, the front side is bound at one place, and the back side is bound at one place. Although the description of the operation of the stapler 22 is omitted, the stapler 22 itself has almost the same configuration as that of a commercially available electric (solenoid) or motor-driven automatic stapling apparatus. The sheets are bound. 5 and 6, reference numeral 21a denotes an alignment reference plate.
[0040]
In FIG. 1, reference numerals 24 and 25 denote first and second trays on which sheets discharged from a discharge port 50 formed in a side wall 1a of the main body 1 of the sheet post-processing apparatus are stacked. Reference numeral 26 denotes a tray unit to which the first and second trays 24 and 25 are attached in the up-down direction and inclined to the main body 1 side. The tray unit 26 is vertically movably attached to the side wall surface 1a of the main body 1 of the sheet post-processing apparatus, and is vertically moved by a driving source (not shown) built in a lower portion thereof.
[0041]
The side wall surface 1a of the main body 1 of the sheet post-processing apparatus is configured to prevent or support the sheet discharged to the upstream side of the sheet stacked on the first and second trays 24 and 25 from coming into contact with the inclined end. Upper and lower regulating members (hereinafter, referred to as “upper slewing guide” and “lower slewing guide”) 27 and 27a are provided (see FIG. 7).
[0042]
In FIG. 7, a swing guide 31 rotatably holds a movable discharge roller 33, and rotates a cam 35 shown in FIG. 8 by a driving source M in a direction indicated by an arrow in FIG. The movable discharge roller 33 is pressed downward against the second discharge roller 32 as shown in FIG.
[0043]
The swing guide 31 swings upward so as to separate the movable discharge roller 33 from the second discharge roller 32 in a staple mode to be described later, so that the two rollers 32, 33 cannot be discharged from the sheet dischargeable state. It plays a role as switching means for setting the state.
[0044]
In FIGS. 7 and 9, the stopper 30 pivots around the pivot shaft 30a when the tray is moved, and is fitted and locked in the groove 34a of the rising saw blade shutter 34 as shown in FIG. When the first tray 24 passes through the outlet 50 with the outlet 50 closed, the sheets S stacked on the first tray 24 are prevented from flowing back to the outlet 50.
[0045]
The stopper 30 is rotated in the Y direction shown in FIG. 7 to release the lock of the saw blade shutter 34 when the sheet is discharged, and in a staple mode to be described later, the stopper 30 shown in FIG. As shown in b), similarly to the swing guide 31, it is configured to rotate in a direction to release the discharge port 50. In the same figure, reference numeral 271 indicates a rib formed on the upper slender guide 27.
[0046]
Next, the operation of the sheet post-processing apparatus thus configured will be described. When a sheet is discharged without performing stapling, the sheet is directly discharged to the first and second trays 24 and 25. FIG. 11 shows a case where sheets are discharged to the first tray 24.
[0047]
When the non-staple mode is selected by the user, the swing guide 31 swings by the cam 35 (see FIG. 8) to a position where the movable discharge roller 33 is pressed against the second discharge roller 33 as shown in FIG. . The scraper shutter 34 is located below the second discharge roller 32 so as not to hinder sheet discharge.
[0048]
In this state, the sheet discharged from the main body 200 of the copying machine passes through the transport path 6 shown in FIG. 4 to the roller pairs 5 and 17 and is further discharged downstream by the roller pairs 5 and 17. The paper is directed toward the first tray 24 by the swing guide 31, is discharged from the discharge port 50 via the discharge rollers 32 and 33, and is sequentially stacked on the first tray 24. Alternatively, depending on the size, the sheets are sequentially stacked on the first tray 24 discharged from the discharge port 50 through the discharge rollers 32 and 33 through the roller rows 14, 16 and 18 through the transport path 8.
[0049]
When a large amount of normal sheets S are to be taken, first, the sheet presence sensors 24a and 25a (see FIG. 4) installed in the first and second trays 24 and 25 (see FIG. 4) are used. After checking that no sheet remains in the first tray 24, the tray unit 26 moves to a predetermined position for receiving the first sheet of the first tray 24.
[0050]
Further, when the number of stacked sheets reaches a certain number, the tray unit 26 (see FIG. 4) moves down to a position determined such that the upper surface of the stacked sheets is substantially the same as the surface receiving the first sheet. I do. When the above operation is repeated and it is detected that the maximum amount of sheets has been stacked in the tray, a stop signal is output to the main body 200 of the copying machine, and the discharge of the sheets is temporarily stopped.
[0051]
Next, the tray unit 26 is lowered to a position where the first sheet of the second tray 25 is set so as to stack the sheets on the second tray 25. After that, the copying operation is restarted by the main body 200 of the copying machine, and the stacking of sheets is restarted. Thereafter, the same operation as described above is repeated until the second tray 25 is full.
[0052]
By the way, in the present embodiment, the main body 200 of the copying machine is of a digital type, and the main body 200 of such a copying machine is composed of a scanner unit for reading an image of a document and a printer unit for reproducing the image. And each can operate independently. In other words, the scanner irradiates the original with a lamp and decomposes the reflected light into small points (pixels) using a light receiving element, and at the same time converts it into an electric signal (photoelectric conversion) corresponding to the density of the original. The drum irradiates the drum with a laser beam based on the electric signal sent from the unit, forms an electrostatic latent image on the drum, and forms a copy image through developer, transfer, and fixing.
[0053]
By connecting an interface 500 to a digital copying machine as shown in FIG. 1, a signal of a document read by a scanner unit is transferred to another facsimile 501, and an electric signal received from another facsimile It is also possible to send the image to a printer unit through 500 and print the image on a sheet.
[0054]
Similarly, an image signal received from a computer device 502 such as a personal computer can be sent to a printer unit via an interface 500 and copied to a sheet, and an image read by a scanner unit can be taken into a personal computer via the interface 500. It has become.
[0055]
As described above, the current digital copying machine not only reads and copies a document sent from the ADF 300 or a document placed on the platen glass 101, but also uses it as a facsimile by interposing the interface 500. It can also be used as a personal computer printer.
[0056]
By the way, in order to use the present apparatus 100 in this way, sheets are sorted into different trays and stacked, or depending on the user's request, each tray is numbered, and the number of sheets on the tray desired by the user is increased. It is necessary to load sheets to
[0057]
For this reason, in the present embodiment, for example, output sheets in the copy mode are stacked on the first tray 24, and output sheets from the personal computer are stacked on the second tray 25.
[0058]
Next, the operation of discharging sheets to each tray will be described. First, a case in which sheets S in the copy mode are stacked from a state in which a certain number of output sheets are received from the personal computer as shown in FIG. 10, that is, a case where the first tray 24 is used will be described. When the first tray 24 is used after receiving a certain number of output sheets from the personal computer, the tray unit 26 moves down to the position where the first sheet of the first tray 24 is received. In the copy mode, the operation is the same as that in the copy mode except that the number of sheets stacked in the tray does not reach the maximum, but drops.
[0059]
Next, a case where output sheets of a personal computer or the like are stacked in a state where a certain number of output sheets or the like in the copy mode are received on the first tray 24, that is, a case where the first tray 24 is used will be described.
[0060]
With the sheets loaded on the first tray 24, the tray unit 26 is raised to load the sheets on the second tray 25. At this time, as shown in FIG. 9A, the sheet shutter 34 rises to close the space of the F section so that the sheet S does not enter the space of the F section indicated by oblique lines in FIG. 24 can move upward while the sheets S are stacked. The sheet abutting surface of the snowboard shutter 34 has a rib shape so that the sheet S can slide easily, similarly to the sheet abutting surface 31b (see FIG. 8) of the swing guide 31 and the lower snowboard guide 27a. .
[0061]
With such a configuration, since the sheet S can pass through the discharge port 50 without flowing backward, the first tray 24 can move upward while the sheet S is stacked. Become. Further, by using the sheet abutting surface 31b of the swing guide 31 as a part of the upper sliding guide 27, the interval between the trays can be reduced, and the tray unit 26 can be downsized.
[0062]
The operation described above is an operation in the case of moving from the second tray 25 to the first tray 24, but is the same regardless of which tray is started.
[0063]
Next, the stapling operation of the sheet post-processing apparatus will be described. First, at the time of staple sorting in which copying is performed by stapling, the sheets are not directly loaded on the first and second trays 24 and 25, but are first loaded on the processing tray 38 in FIG. When the staple sort mode is selected by the user, the sheet post-processing apparatus performs the following operation.
[0064]
FIG. 11 is a diagram illustrating a state in which the first sheet is stacked on the staple tray. First, when the first sheet is conveyed, as shown in FIG. 11A, the swing guide 31 is at the lowered position, and the sheet S is transferred to the first discharge roller 17 and the second discharge roller. 32 is conveyed to the left in FIG.
[0065]
FIG. 11B illustrates a state in which the rear end of the sheet S has passed the discharged sheet detection sensor 13 and a predetermined time has elapsed, and the sheet S has further advanced downstream from the discharge matching belt 19. In this state, the second discharge roller 32 stops. Further, the sheet S stops at a position advanced by a predetermined amount from the discharge alignment belt 19 rotating together with the first discharge roller 17.
[0066]
Next, FIG. 11C shows a state in which the sheet S on the processing tray 38 is forcibly pulled back to the upstream side. Here, the second sheet discharge roller 32 rotates in the direction of arrow G, and pulls the sheet S back upstream in the transport direction. Further, while the rear end of the sheet S reaches a position where the sheet S comes into contact with the discharge alignment belt 19, the swing guide 31 rises to a position as shown in FIG. .
[0067]
The processing tray 38 is attached to the inside of the main body 1 of the sheet post-processing apparatus at an angle such that the sheets S are stacked on the processing tray 38 by its own weight. Further, the first tray 24 is positioned above the non-staple mode so as to support the rear end of the sheet S and assist the sheet S to return to the upstream side in the discharge direction.
[0068]
On the other hand, as shown in the figure, the sheet S discharged onto the processing tray 38 is allowed to slide down its own weight toward the upstream in the discharging direction by tilting the processing tray 38 and increasing the position of the first tray 24. Although assisted, it is further urged in the upstream direction on the processing tray 38 by the discharge alignment belt 19 that rotates in the direction of the arrow in synchronization with the first discharge roller 17.
[0069]
Therefore, the sheet S abuts against the alignment abutting member 20 and is aligned in a direction perpendicular to the discharge direction. Also, in the widthwise alignment of the sheet S, the width shift plate 21 (see FIGS. 5 and 6) starts operating a predetermined time after the sheet S falls on the processing tray 38 and hits the alignment abutting member 20. This is performed by moving the sheet S from the back side of the main body toward the near side by a predetermined dimension rather than the width dimension of the sheet S, and aligning the sheet S with the near side.
[0070]
Here, the discharge alignment belt 19 is made of a rubber member having flexibility (elasticity) and a high friction coefficient. Therefore, when the sheet S shown in FIG. 12A is rotated in the direction of the arrow to align the sheet S, the sheet S bends due to its elasticity and is deformed to the upstream side in the sheet discharging direction as shown in FIG. I do. Therefore, the rear end of the sheet S to be conveyed next falls to the downstream position 19 a of the deformed discharge alignment belt 19.
[0071]
FIG. 12A is a diagram illustrating a state immediately after the sheet S in the staple mode is discharged to the processing tray 38. In FIG. 12A, the paddle 71 is formed of an elastically deformable member, and is stopped at a position above the swing guide 31 so as not to hinder sheet discharge, and the sheet S is discharged onto the processing tray 38. Then, one rotation operation is performed, and the rear end of the sheet S is pulled back to the nip point of the discharge alignment belt 19. The paddle 71 rotates intermittently. Further, the sheet S that has entered the nip point of the discharge alignment belt 19 is conveyed in the direction of the discharge alignment belt 19 and the alignment butting member 20 (see FIG. 11) by its own weight.
[0072]
The belt roller 61 is provided on the belt moving plate 62, is disposed inside the discharge alignment belt 19, and is movable by the belt moving plate 62. The discharge alignment belt 19 is a member having elasticity, and can be easily deformed by the belt roller 61. Normally, when the discharge roller 17 rotates in the discharge direction to discharge the sheet to the first tray 24, the discharge alignment belt 19 is deformed to the downstream side in the transport direction by its own frictional force (FIG. 12B). By moving the moving plate 62 in the direction of the arrow, the belt roller 61 pulls the discharge alignment belt 19 back in the upstream direction.
[0073]
Accordingly, the rear end of the conveyed sheet S falls to a position indicated by reference numeral 19c on the upstream side of the downstream position 19a shown in FIG. Therefore, since the amount of sheet jump is small, it is easy to drop under its own weight.
[0074]
Further, since the time when the sheet is discharged to the processing tray 38 can be detected by the discharged sheet detection sensor 13 (FIG. 4), the belt moving plate 62 is moved within a predetermined time after the sheet is discharged to the processing tray 38. The belt rollers 61 and 61a are moved downstream by moving to the position shown in FIG. 12 (b). Here, with respect to the belt roller 61 rotatably supported by the belt moving plate 62, the small belt roller 61a is also rotatably supported by the belt moving plate 62 so as to sandwich the discharge alignment belt 19. The belt roller 61 and the small belt roller 61a do not hinder the rotation of the discharge alignment belt 19 with respect to the belt moving plate 62. Therefore, the discharge alignment belt 19 is forcibly pushed back in the downstream direction.
[0075]
Here, the contact point 19d between the discharge alignment belt 19 and the sheet S is located downstream of the upstream position 19c. For this reason, even if the sheet S does not slide down on the processing tray 38, the discharge alignment belt 19 can draw the sheet S in the upstream direction.
[0076]
After the discharge alignment belt 19 abuts the sheet S against the alignment abutting member 20 to perform alignment in the conveyance direction by the above operation, the width shift plate 21 (see FIG. 5) moves the sheet S in the direction of the alignment reference plate 21a. Go to align. At this time, if the sheet is a regenerated sheet having an unstable friction coefficient, a sheet that is likely to be stuck due to electrification of static electricity, or a sheet having a longer dimension in the conveyance direction than the width of the sheet, Due to the dimensional restrictions of the sheet post-processing apparatus 1, the width shifting plate 21 can perform the pressing operation only at the rear end near the alignment butting member 20 of the sheets stacked on the processing tray 38.
[0077]
For this reason, the sheet rarely moves and is aligned with the alignment abutting member 20 while maintaining the parallelism. As a result, the sheet may be aligned with the alignment abutting member 20 in an oblique state during the alignment operation in the sheet width direction. In such a case, when the sheets are stapled, misalignment occurs. Therefore, when the sheet is again aligned in the sheet conveyance direction by the paddle 71, the sheet can be reliably abutted against the alignment abutting member 20 to perform alignment.
[0078]
Hereinafter, the above operation is repeated until the second and subsequent sheets S are stacked on the processing tray 38 by the number set by the user. When the number of sheets set by the user is aligned on the processing tray 38, the swing guide 31 descends, and the movable discharge roller 33 and the discharge roller 32 sandwich the sheet bundle. Thereafter, the stapler operates to perform an operation of stapling to a position set by the user.
[0079]
The state at this time is shown in FIG. Further, after the stapling is completed, the discharge roller 32 rotates in a direction for conveying the sheet to the downstream side, and the stapled sheet bundle is stacked on the stacking tray 24.
[0080]
The main unit 1 of the sheet post-processing apparatus controls the size information of the sheet conveyed from the main body 200 of the copying machine and the control unit 510 that manages the discharged sheet detecting unit 13 that counts the number of sheets stacked on the processing tray 38. Therefore, it is possible to switch whether or not to execute the alignment operation in the transport direction by the paddle 71 after the width adjustment based on the size and the number of sheets stacked on the processing tray.
[0081]
Specifically, when the alignment operation in the transport direction is performed by the paddle 71 after the width adjustment, the processing time of the sheets stacked on the processing tray 38 needs to be longer than when not performed. Depending on the sheet processing speed of the main body 200 of the copying machine, when the mode for stacking the sheets on the processing tray 38 is selected, the sheet discharge interval of the main body 200 of the copying machine is increased, and a waiting time is required.
[0082]
Therefore, for a small-sized sheet (for example, A4, B5, etc.) in which the normal processing time is short and the length of the sheet in the transport direction is short, the processing tray can be adjusted without performing the alignment operation in the transport direction after the width adjustment. 38 can be loaded without any problem. Therefore, priority is given to the processing time of the main body 200 of the copying machine, and there is no need to perform the alignment operation in the transport direction after the width adjustment.
[0083]
However, large-size (A3, B4, etc.) sheets are discharged inside the copier main body 200 until the next sheet is discharged from the copier main body 200 after the sheet is discharged onto the processing tray 38. Takes a long time to process the sheet, the sheet processing time in the conveying direction has a margin, and the dimension in the conveying direction is longer than the dimension in the width direction of the sheet. Also, due to the dimensional restrictions of the sheet post-processing device, the width shift plate 21 can only perform the pressing operation at the rear end near the alignment butting member 20 of the sheets stacked on the processing tray 38. For these reasons, a large-sized (A3, B4, etc.) sheet is rarely moved and aligned while maintaining parallelism with the alignment abutment member 20 during the alignment operation in the sheet width direction. The sheet may be aligned with the aligning butting member 20 in a state where the sheet is inclined.
[0084]
Therefore, the control unit 510 (see FIG. 1) controls the rotation of the paddle 71 based on the sheet size information, and performs the alignment operation in the sheet conveying direction again. As a result, a large-sized sheet (A3, B4, LDR, etc.) is reliably pressed against the aligning butting member 20, and the alignment of the sheet in the transport direction is reliably performed.
[0085]
Furthermore, a large-sized sheet (A3, B4, LDR, etc.) has a longer dimension in the transport direction than the width of the sheet. Further, the width approaching plate 21 can only press the rear end of the sheet stacked on the processing tray 38 in the vicinity of the alignment butting member 20 due to the dimensional restriction of the sheet post-processing apparatus. For these reasons, if the number of sheets stacked on the processing tray 38 is large at the time of the alignment operation in the sheet width direction, the sheets are aligned and abutted depending on the curl of the previously stacked sheet and the conditions of the friction coefficient. The sheet is rarely moved and aligned while maintaining the parallelism with respect to the member 20, and the sheet may be aligned with the alignment abutting member 20 in an oblique state.
[0086]
Therefore, the control unit (see FIG. 1) 510 controls the rotation of the paddle 71 based on the number of stacked sheets, and performs the alignment operation in the sheet conveying direction again. As a result, the large-sized sheets (A3, B4, etc.) are reliably pressed against the alignment abutting member 20, and the alignment of the sheet in the conveying direction is reliably performed.
[0087]
Further, based on a combination of the sheet size information and the information on the number of sheets stacked on the processing tray 38, it is determined whether or not the paddle 71 performs the transport direction alignment operation after the width direction alignment operation. May be.
[0088]
Further, when binding the sheet bundle, the sheets are sequentially discharged from the main body 200 of the copying machine. Therefore, the sheet post-processing apparatus 600 stores the first page sheet of the discharged sheet of the next job in the main body 1 of the sheet post-processing apparatus. An operation is performed in which the sheet is made to stay and is discharged while being stacked on the second sheet.
[0089]
The operation will be described with reference to FIG. FIG. 14A illustrates a state where the sheet S has begun to enter the main body 1 of the sheet post-processing apparatus. The first sheet S1 discharged from the main body 200 of the copying machine is sent to the buffer path 8 when the upstream ends of the flappers 3 and 4 are inclined downward. The sheet S1 sent to the buffer path 8 is wound around a buffer roller 9 and sent in the direction of the arrow shown in the figure. Here, the flapper 39 rotates and guides the sheet S1 so as to be fed in the direction of the roller 15, and the sensor 11 detects the leading end of the sheet S1 and stops in a state as shown in FIG.
[0090]
Then, when the second sheet S2 enters, the buffer roller 9 starts rotating, and as shown in FIG. 14C, the first sheet S1 and the second sheet S2 are stacked and conveyed. . Further, when the rear end of the first sheet S1 passes through the flapper 39, the flapper 39 rotates so that the sheet S is fed in the direction of the discharge rollers 17 and 18, as shown in FIG. The sheets are discharged onto the processing tray 38 with the two sheets stacked.
[0091]
By performing the above operation, while the stapler 22 is performing the stapling operation, the sheet S is not discharged from the discharge rollers 17 and 18, the stapling operation can be performed, and the operation of the main body 200 of the copying machine is stopped. I can't. Note that the third or more sheets S can be wound around the buffer roller 9 in order to obtain more time for performing the stapling operation.
[0092]
(Sheet standby position for stack discharge control)
As described above, when a plurality of sheets are stacked and ejected, the sheet post-processing apparatus 600 causes the preceding sheet S1 waiting in the buffer path 8 and the subsequent sheet S1 ejected from the main body 200 of the copying machine. It is necessary to convey the sheet S2 so that the amount of deviation between the leading end and the sheet S2 is constant. For this reason, the control unit 510 starts the rotation of the buffer roller 9 when the succeeding sheet S2 passes through the entrance sensor 10 shown in FIG. 4 or after a predetermined clock elapses after the succeeding sheet S2 passes through the entrance sensor 10, The deviation amount between the leading end of the preceding sheet S1 and the leading end of the succeeding sheet S2 is made constant.
[0093]
However, the conveyance speed of the succeeding sheet S2 discharged from the main body 200 of the copying machine is changed depending on the image forming mode, the type of the sheet, and the like. On the other hand, the control unit 510 needs to change the activation timing of the buffer roller 9 in order to keep the amount of deviation between the leading ends of the preceding sheet S1 and the succeeding sheet S2 constant.
[0094]
Therefore, the conveyance speed of the succeeding sheet S2 according to the image forming mode and the type of sheet is controlled by the main body 200 of the copying machine. Therefore, the control unit 510 controls the rotation of the buffer roller 9 and The feeding timing of the preceding sheet S1 to be stopped in the buffer path 8 is changed according to the transport speed of the sheet S2.
[0095]
The control unit 510 holds the preceding sheet S1 at a fixed position in the buffer path 8, and when the conveying speed of the succeeding sheet S2 is high, the control unit 510 controls the buffer roller 9 immediately after the succeeding sheet S2 passes through the entrance sensor 10. Start. When the conveying speed of the succeeding sheet S2 is low, the buffer roller 9 is started after a lapse of a predetermined time after the succeeding sheet S2 passes through the entrance sensor 10. As described above, by changing the conveyance start timing of the preceding sheet S1 according to the conveyance speed of the succeeding sheet S2, the amount of deviation of the leading ends of both sheets S1 and S2 can be made constant.
[0096]
The conveyance speed of the succeeding sheet S2 is controlled by the main body 200 of the copying machine as described above. However, generally, the succeeding sheet S2 is conveyed at the same speed as the preceding sheet S1. Therefore, the transport speed of the succeeding sheet S2 may be detected by detecting the transport speed of the preceding sheet S1.
[0097]
Note that the above-described overlap discharge control is effective when performing a sort process or a process of binding a sheet bundle. However, in other cases, the overlap discharge control may be performed. Conversely, it is naturally possible to set so as not to perform the overlap discharge control.
[0098]
In the sheet post-processing apparatus 600 according to the above-described embodiment, the sheet S discharged to the processing tray (sheet stacking unit) 38 by the discharge rollers 17 and 18 is discharged by a paddle (first sheet conveyance alignment unit, rotating member) 71. The sheet is pulled back to the nip point between the alignment belt (second sheet conveying alignment means, rotating body) 19 and the processing tray 38, and then abuts against the alignment abutting member (sheet receiving means) 20 by the frictional force of the discharge alignment belt 19. And the transport direction is adjusted. Then, the sheet is pressed against an alignment reference plate (sheet width aligning means) 21a by a width shifter (sheet width aligning means) 21 to perform an alignment operation in the width direction.
[0099]
At this time, when the sheet is a sheet having a large coefficient of friction, a sheet which is easily charged with static electricity, or a sheet having a size in the conveying direction longer than the sheet in the width direction, or when the number of stacked sheets is large, It is difficult for the aligned sheet to move in parallel along the alignment abutting member 20, and the alignment in the sheet conveying direction may be disturbed. In such a case, the control unit (control means) 510 rotates the paddle 17 again, presses the sheet against the aligning butting member 20, and performs the aligning operation in the sheet conveying direction. The number of stacked sheets and the length of the sheets are detected by a sensor (not shown).
[0100]
As a result, the sheet post-processing apparatus 600 is provided with a regenerated sheet having an unstable friction coefficient, a sheet which is easily charged and stuck due to static electricity, or a sheet having a longer dimension in the conveyance direction than the width of the sheet. Even if there is a possibility that the paddle 17 is aligned with the alignment abutting member at an angle during the alignment operation in the width direction, the paddle 17 performs the alignment operation in the transport direction again, so that the alignment in the sheet transport direction is reliably performed. It can be carried out. Further, when the ends in the sheet conveying direction are aligned, the stapler (sheet binding means) 22 can reliably perform the sheet binding operation.
[0101]
Next, referring to FIG. 13, the sheet bundle S1 that has been bound on the processing tray 38 by the stapler (sheet binding unit) 22 or that has been sorted for each designated number of sheets is placed on the first tray 24 (or the second tray 25). The operation at the time of discharging the paper is described.
[0102]
The sheet bundle subjected to the sheet processing on the processing tray 38 is discharged onto the first tray 24 (or the second tray 25) by the discharge roller 32 and the moving discharge roller 33. At this time, a sheet size having a relatively long transport direction length (for example, A3, B4, LDR, or the like) such that the tray length x of the processing tray 38 and the transport direction length y of the sheet have a relationship of y ≧ 2.5x. 13A, the sheet bundle S2 already loaded on the first tray 24 (or the second tray 25) comes into contact with the end of the sheet bundle S2 on the first tray 24 (or the second tray 25) in the conveyance direction at the point P for the processing tray loading time of the S1. .
[0103]
At this time, in the color transfer mode, the charge amount on the sheet surface due to the characteristics of the transfer toner and the sheet holding temperature due to the heat applied by the fixing device are relatively higher than in the black and white transfer mode. At the contact point P of S2, an adhesion phenomenon occurs due to heat and electrification, and the adhesion occurs when the transfer image is peeled or when the sheet S1 is discharged from the processing tray to the first tray 24 (or the second tray 25). There is a possibility that S2 is extruded by the adhesive force of the surface P and is dropped from the tray. Therefore, in the case of a sheet size having a long length in the conveyance direction (for example, A3, B4, LDR or the like), a sheet bundle of 15 sheets or more, and a double-side transfer mode, the present embodiment controls as follows.
[0104]
After the last sheet of the bundle constituting the sheet S1 is discharged onto the processing tray 38 via the discharge rollers 17 and 18, the sheet is abutted against the aligning abutting member 20 by the discharge aligning belt 19, and is aligned in the transport direction and width-adjusted. After the alignment in the width direction is performed by the plate 21, the first tray 24 (or the second tray 25) is moved downward from the sheet discharge position (FIG. 13A) in synchronism with the timing when the stapling is completed. After being retracted to the retracted position (FIG. 13B), the sheet discharge position (by the discharge roller 32 and the moving discharge roller 33) is discharged until the sheet bundle S1 is discharged onto the first tray 24 (or the second tray 25). Operation control is performed again to return to FIG.
[0105]
By including such operation control, a part of the contact surface P between the sheets S1 and S2 can be forcibly separated or temporarily completely separated depending on the sheet size, and the adhesive force acting on the adhesive surface P can be reduced. It has a relaxing effect. Therefore, when discharging S1 from the processing tray to the first tray 24 (or the second tray 25), it is possible to prevent the sheet S2 from being pushed out by the bonding surface P and being dropped from the tray.
[0106]
In the present embodiment, in the case where the number of sheets to be loaded on the processing tray is temporarily set to the single-sided transfer mode, or when the number of sheet bundles is 15 or less, and when the sheet size is short in the transport direction (for example, A4, B5, LTR, etc.), The movement control of the first tray 24 (or the second tray 25) is controlled not to be performed in connection with the reduction of the operation sound or the like. However, even in such a case, since the productivity is not reduced, the same movement is performed. It is also possible to perform control.
[0107]
In this embodiment, the first tray 24 is controlled to move downward, but the same effect can be obtained by moving the first tray 24 at the same timing in the transport direction.
[0108]
【The invention's effect】
As described above, in the present invention, in the color transfer mode, a sheet due to sticking of the already-stacked sheet bundle and the processing tray sheet bundle which occurs in the case of a long sheet size (for example, A3, B4, LDR, or the like) in the transport direction. In response to problems such as poor discharge and poor sheet loading on the tray, the sheet loaded on the processing tray is controlled by controlling the stack tray to move downward while the sheets are being loaded on the processing tray. The contact surface between the unprocessed end of the bundle (the leading end in the transport direction) and the stack tray surface or the upper surface of the sheet bundle already loaded on the stack tray is moved or temporarily separated, so that the adhesive force is reduced. It is possible to prevent defective discharge and defective sheet stacking on the tray.
[0109]
Therefore, (1) high-precision sheet alignment is possible even for color images such as posters and photographs, printed matter having a relatively high image density, and paper printed over the entire area. {Circle around (2)} Even in the recent large-capacity and multi-sheet processing, the stacked state of the sheet bundle can be maintained.
[0110]
This makes it possible to maintain and satisfy high-precision sheet processing with a simple configuration, and finally obtain an image forming apparatus that realizes “stable high-quality sheet processing”.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an entire image forming apparatus of the present invention.
FIG. 2 is a perspective view of a monochrome / color image forming apparatus.
FIG. 3 is a cross-sectional view of a monochrome / color image forming apparatus.
FIG. 4 is a cross-sectional view showing the entire sheet post-processing apparatus.
FIG. 5 is a plan view of the processing tray unit of FIG. 4;
FIG. 6 is a side view of the processing tray unit of FIG. 4;
FIG. 7 is a perspective view of a swing guide portion of the sheet post-processing apparatus.
FIG. 8 is an enlarged front sectional view of a main part of the sheet post-processing apparatus.
FIG. 9 is an explanatory diagram of an operation of a sheet shutter of the sheet post-processing apparatus.
(A) Diagram showing the state in which the sheet shutter blocks the sheet discharge section
(B) A diagram showing a state in which the sheet shutter opens the sheet discharge unit.
FIG. 10 is an operation diagram of discharging a sheet to a processing tray in a staple mode;
FIG. 11 is a diagram illustrating a sheet discharging operation to a processing tray in a staple mode of the sheet post-processing apparatus.
(A) Operation diagram during discharge of sheet to processing tray
(B) Operation diagram with the sheet dropped on the processing tray
(C) Operation diagram when the sheet is pulled into the alignment butting member side
(D) A diagram in which the sheet is abutted against the alignment abutting member and the swing guide is raised.
(E) Diagram when sheets have been loaded
FIG. 12 is an operation diagram of a discharge alignment belt for aligning sheets on a processing tray of the sheet post-processing apparatus.
(A) A diagram showing a state immediately after a staple mode sheet is discharged to a processing tray.
(B) A diagram in which the discharge alignment belt is deformed downstream in the sheet conveying direction by its own frictional force
FIG. 13 is an explanatory diagram illustrating an operation of discharging a sheet bundle on a processing tray.
(A) Diagram with first tray at sheet discharge position
(B) Diagram with the first tray in the retracted position
FIG. 14 is an explanatory diagram illustrating an operation of retaining a plurality of sheets in a main body of the sheet post-processing apparatus and discharging the sheets to a processing tray.
(A) A diagram showing a state in which a sheet has begun to enter the main body of the sheet post-processing apparatus.
(B) A diagram showing a state where the preceding sheet is held in the buffer path
(C) Diagram showing a state where the subsequent sheet has begun to be fed into the buffer path
(D) Diagram showing a state where two sheets are stacked and pass through the buffer path
[Explanation of symbols]
S sheet
1 Body of sheet post-processing device
9 Buffer roller
17 Discharge roller
18 Presser roller
19 Ejection matching belt
20 Alignment butting member
21 Width adjustment plate
22 stapler (sheet binding means)
24 First tray (second loading means)
25 Second tray (second loading means)
38 Processing Tray (First Loading Means)
71 paddle

Claims (6)

In a sheet processing apparatus including a bundle conveying unit configured to convey a bundle of sheets from a first stacking unit to a second stacking unit,
The second stacking unit has two positions, a stacking position for receiving and stacking a sheet bundle from the first stacking unit and a retreat position located below the stacking position, and is loaded on the first stacking unit. A sheet processing apparatus, wherein the second stacking means reciprocates between the stacking position and the retreat position during the operation. A first stacking unit for stacking sheets discharged from the image forming apparatus main body, a second stacking unit disposed downstream of the first stacking unit, and a stacking unit on the first stacking unit Aligning means capable of aligning sheets in a direction intersecting the sheet conveying direction; sheet bundle processing means for processing a sheet bundle stacked on the first stacking means; and a sheet bundle aligned by the aligning means. A sheet processing apparatus comprising: a bundle conveying unit configured to convey a bundle from the first stacking unit to the second stacking unit;
The second stacking unit has two positions, a stacking position for receiving and stacking a sheet bundle from the first stacking unit and a retreat position located below the stacking position, and is loaded on the first stacking unit. A sheet processing apparatus, wherein the second stacking means reciprocates between the stacking position and the retreat position during the operation. The second stacking unit completes the movement from the retracted position to the stacking position by the time the sheet stack stacked on the first stacking unit is started to be conveyed to the second stacking unit by the bundle conveying unit. The sheet processing apparatus according to claim 1, wherein the sheet processing is performed. The second stacking unit has two positions, a stacking position for receiving and stacking a sheet bundle from the first stacking unit and a retreat position located below the stacking position, and the sheet conveying direction of the first stacking unit. Assuming that the length is x and the length of the processing sheet in the transport direction is y, when the relationship between x and y satisfies {y ≧ 2.5x}, the second sheet is being loaded on the first loading means. 3. The sheet processing apparatus according to claim 1, wherein the stacking means reciprocates between the stacking position and the retracted position. The second stacking unit has two positions, the stacking position and a retracted position located below the stacking position, when the image forming surface of the sheet discharged from the image forming apparatus reaches both sides of the sheet, 3. The sheet processing apparatus according to claim 1, wherein the second stacking unit reciprocates between the stacking position and the retracted position while the stacking process is being performed on the first stacking unit. The image forming apparatus is an apparatus capable of forming a color or black-and-white image, and the second stacking unit is configured to output the image of the sheet discharged from the image forming apparatus in color output from the stacking position and the stacking position. The apparatus has two retreat positions located below, and the second loading means reciprocates between the loading position and the retreat position during the loading process on the first loading means. Item 3. The sheet processing apparatus according to item 1 or 2.

Images