JP7227750B2 - Sheet stacking device and image forming system - Google Patents

Description

The present invention relates to a sheet stacking device for stacking sheets and an image forming system for forming an image on a sheet.

Conventionally, an image forming apparatus performs print processing on sheets, temporarily places the printed sheets on a processing tray (first stacking unit), and performs post-processing such as binding processing and shift paper discharge processing. An image forming system that discharges to a stack tray (second stacking unit) is known (for example, Japanese Unexamined Patent Application Publication No. 2002-100002). In such an image forming system, a moving means such as a knurled belt is used to position the sheet on the processing tray. The knurled belt has knurls formed on its peripheral side, and by rotating with this peripheral side in contact with the sheet surface, the sheet is moved by friction with the sheet surface, and is rake into a predetermined position. Further, in recent years, in such image forming systems, there has been an increase in the number of image forming units that employ an inkjet method, and systems that perform post-processing on sheets printed by an inkjet method are also known (see, for example, Patent Document 2). ).

JP 2015-16970 A JP 2017-132636 A

However, when an image is formed by an inkjet method as in Patent Document 2, when the image ratio is high (for example, a solid image is printed on the entire surface), the moisture content of the sheet increases and the hardness decreases. In this case, the knurled belt used to rake the sheet in the post-processing device may contact the sheet and rotate, damaging the contact portion of the sheet surface. Therefore, if the knurled belt contacts the image forming surface of the sheet, image defects may occur, and if the knurling belt contacts the back side of the image forming surface of the sheet, the sheet itself may be damaged.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a sheet stacking apparatus and an image forming system capable of suppressing damage to the sheet surface caused by a moving means that moves the sheet in contact with the sheet surface even when the moisture content of the sheet is high.

A sheet stacking device according to the present invention is a sheet stacking device for stacking image-formed sheets having at least an image formed on the upper surface thereof by an image forming apparatus, the sheet stacking apparatus comprising: a receiving section for receiving the image-formed sheets from the image forming apparatus; a first discharging device for discharging the image- formed sheet received by the receiving unit in a discharging direction ; a first stacking unit capable of stacking the image-formed sheet discharged by the first discharging device; a regulating means capable of regulating the position of the edge of the image -formed sheet stacked on the stacking section; moving means for moving the sheet so that the portion abuts against the regulating means; second discharging means for discharging the image-formed sheet stacked on the first stacking portion; A second stacking unit capable of stacking the image-formed sheets discharged from the stacking unit , and an air blower capable of blowing air onto the upper surfaces of the image-formed sheets before being stacked on the first stacking unit. It is characterized by

An image forming system according to the present invention includes an image forming apparatus having an image forming unit for forming an image on a sheet; characterized by comprising

According to the sheet stacking apparatus and the image forming system of the present invention, it is possible to suppress damage to the sheet surface caused by the moving means that moves the sheet while contacting the sheet surface even when the moisture content of the sheet is high.

1 is a schematic diagram of an image forming system according to an embodiment; FIG. Schematic of the post-processing unit of embodiment. The block diagram which shows the control structure of embodiment. 8A and 8B are diagrams for explaining the bundle forming process by the post-processing unit of the embodiment, in which (a) is when the sheet is conveyed to the discharge roller, (b) is when the sheet is discharged to the processing tray, and (c). (d) is when the sheet bundle is pushed out to the stack tray. 1A and 1B are schematic plan views showing a post-processing unit of an embodiment, where (a) is a conveying path on the upstream side of a discharge roller, and (b) is a processing tray; FIG. 8A is a diagram for explaining the operation of the post-processing unit upstream of the discharge rollers of the embodiment, FIG. In case (b), when the double-sided printed sheet is nipped only by the discharge rollers, sheet conveyance is stopped and air is blown. 4 is a flow chart showing the procedure of operation of the air blower according to the embodiment; 4 is a flow chart showing the procedure of operation of a blower device according to a modification of the embodiment;

An embodiment will be described with reference to FIGS. 1 to 8. FIG. First, the schematic configuration of the image forming system of this embodiment will be described with reference to FIG.

[Image forming system]
FIG. 1 schematically shows the overall configuration of an image forming system 100 according to this embodiment. As shown in the figure, the image forming system 100 includes an image forming apparatus 101 and a sheet processing apparatus 102 provided side by side. The image forming apparatus 101 includes a feeding unit 10 , an image forming unit 20 and an image reading unit 30 . The sheet processing apparatus 102 is composed of a relay conveying unit 60 and a post-processing unit 70 .

[Image forming apparatus]
First, the image forming apparatus 101 will be described. A feeding unit 10 of the image forming apparatus 101 is provided in the lower portion of the image forming apparatus 101, and includes a plurality of cassette mechanisms 10a, 10b, 10c, and 10d for accommodating image forming sheets of different sizes, and a large-capacity cassette 10e. , for example, feeds a sheet of a size designated by an operator such as a user through the input unit 86 (see FIG. 3) to the feeding path P1. The feeding unit 10 also includes a manual feed tray 10f. Each of the cassette mechanisms 10a, 10b, 10c, and 10d is detachably mounted on the apparatus housing 1, and incorporates a separating mechanism for separating the sheets one by one and a feeding mechanism for feeding the sheets.

A large-capacity cassette 10e and a manual feed tray 10f are connected to the feed path P1. The large-capacity cassette 10e and the manual feed tray 10f are provided on one side (the right side in FIG. 1) of the apparatus housing 1, and the apparatus housing 1 has sheet feeding openings (feeding openings) corresponding to each. 16, 17 are provided. The large-capacity cassette 10e is composed of an option unit that stores sheets of a size that are consumed in large quantities. The manual feed tray 10f is configured to be able to supply special sheets such as thick paper sheets, coating sheets, and film sheets that are difficult to separate and feed. That is, the sheets used in this embodiment include various sheet materials other than plain paper for printing. Examples of sheet materials include paper such as thin paper and cardboard, plastic films such as sheets for overhead projectors, cloth, surface-treated sheet materials such as coated paper, and specially shaped sheets such as envelopes and index paper. material.

The feeding path P1 is provided with a pair of conveying rollers 11 for feeding sheets downstream from the cassette mechanisms 10a, 10b, 10c, 10d and the large-capacity cassette 10e via the feeding paths P1a, P1b, P1e. and a pair of registration rollers 12 are provided. The registration roller pair 12 is provided at the terminal end of the feeding path P1, and corrects the skew of the sheet by coming into contact with the leading edge of the sheet (the downstream end in the conveying direction), and then directs the sheet toward the image forming unit 20. send out. Also, the sheet supplied from the manual feed tray 10f is sent to the registration roller pair 12 via the feeding path P1f.

Each of the cassette mechanisms 10a, 10b, 10c, 10d and the large-capacity cassette 10e is provided with a pickup roller 13, which is an example of a feeding mechanism, and a conveying roller pair 14, which is an example of a separating mechanism. Sheets are supplied one by one to the feeding path P1. A conveying roller pair 15 is provided in the vicinity of the sheet supply port 17 of the manual feed tray 10f in the apparatus housing 1, and conveys the sheet manually fed by the user toward the registration roller pair 12. FIG.

The image forming unit 20 is provided above the cassette mechanism 10a and on the transport path P2, and includes an image forming section 21 having, for example, an ink jet print head. The image forming section 21 is provided at a position facing the conveying belt 22 across the conveying path P2. The image forming unit 21 ejects a liquid such as ink onto a sheet that is conveyed while being supported by the conveying belt 22 along the conveying path P2, so that the liquid adheres to the sheet for printing. The image forming unit 21 of the present embodiment includes a line head capable of simultaneously ejecting ink over a predetermined range in a direction intersecting the sheet conveying direction (in particular, a width direction perpendicular to the conveying direction).

The image forming unit of the present disclosure is not limited to the inkjet method, and includes, for example, a rotating photosensitive drum, a light emitting device such as a laser light emitting device or an LED light emitting device, a developing device, and a cleaner. It may be an electrophotographic unit provided with. In this case, a latent image is optically formed on the photosensitive drum by a light emitting device, and toner is adhered to the latent image by using a developing device. The sheet is conveyed to the conveying path P2 at the timing of image formation on the photosensitive drum, and the toner image is transferred from the photosensitive drum onto the sheet by the transfer charger. A fixing roller arranged downstream of the transfer charger in the sheet conveying direction applies heat generated by a heat source such as a halogen heater to the toner image transferred to the sheet to melt the toner. After that, as the temperature decreases, the toner adheres to the sheet, whereby an image fixed to the sheet is obtained.

The sheet subjected to image forming processing by the image forming unit 20 is conveyed to the sheet reversing path P3, the conveying path P4 for discharging to the first discharging section 40a, or the conveying path P5 for conveying to the relay conveying unit 60. be done. In the path switching unit 23, a switching member (not shown) moves according to the destination of the sheet, and guides the sheet to either the sheet reversing path P3 or the transport paths P4 and P5.

The sheet reversing path P3 is a conveying path for reversing the front and back of the sheet. It is used when conveying to the unit 70 or the like.

A conveying path P4 is a conveying path for discharging the sheet to the first discharge portion 40a. When the sheet is discharged to the first discharge section 40a, the path switching section 23 transfers the sheet from the conveying path P2 to the conveying path P4, and the printed surface of the sheet (the second printed surface in the case of double-sided printing) is The sheet is discharged to the sheet mounting surface (mounting portion) 41 in a face-down state facing downward. The conveying path P4 is curved upward (in an arc) from the substantially horizontal conveying path P2 starting from the path switching portion 23, and extends from the end of the curved portion to the sheet discharge port 24 provided in the apparatus housing 1. formed to face

When the sheet is conveyed to the relay conveying unit 60, the path is not switched by the path switching unit 23, and the sheet is conveyed straight along the conveying path P2. When conveying a sheet to the relay conveying unit 60, if the sheet is conveyed face-up (a state in which the printed surface of the sheet faces upward), the sheet is conveyed face-down without performing the reversing process by the sheet reversing path P3. In this case, the sheet is conveyed after being reversed using the sheet reversing path P3.

The image reading unit 30 is provided above the first discharge portion 40a and the transport path P4, and includes an image reading portion 33 for reading an image of a document, a document feeding tray 31 for placing a document to be fed, It is composed of a document discharge tray 32 to which the document that has been read by the image reading section 33 is discharged. The image reading unit 30 photoelectrically converts the document image read by the image reading section 33 into image data, and outputs the image data as an electric signal to the image forming unit. Note that the image of the document may be read using a platen on which the document is placed, a carriage that reciprocates along the platen, and the image reading section 33 provided on the carriage.

[Sheet processing device]
Next, the sheet processing apparatus 102 will be described. A relay conveying unit 60 of the sheet processing apparatus 102 is a unit for conveying a sheet on which image formation processing has been performed by the image forming unit 20 to the post-processing unit 70 , and has a path switching section 61 . The path switching portion 61 has a transport path P5 for discharging sheets to a stack tray 171 as a second stacking portion of the post-processing unit 70 and a sheet stacking surface 71a on the upper surface of the unit housing 71 of the post-processing unit 70. The conveying path is switched between the conveying path P6 for discharging and the conveying path P6. Sheets passing through the conveying path P5 are discharged toward the post-processing unit 70 by the discharging rollers 62, and sheets passing through the conveying path P6 are discharged toward the sheet mounting surface 71a of the post-processing unit 70 by the discharging rollers 63. . The sheet placement surface 71 a of the post-processing unit 70 constitutes the second discharge section 40 b of the image forming system 100 , and the stack tray 171 constitutes the third discharge section 40 c of the image forming system 100 .

The sheet discharge destination of the sheet processing apparatus 102 is switched between the stack tray 171 and the sheet placement surface 71a depending on whether post-processing such as binding is performed on the sheets. In the present embodiment, the sheet is discharged straight onto the sheet placing surface 71a. Therefore, when the sheet is to be discharged face-down, the first discharge section 40a is used, and when the sheet is to be discharged face-up, the second discharge section 40b is used. You may divide into modes so that it may discharge. Note that when the discharge roller 63 provided on the conveying path P6 is configured to be movable in the width direction perpendicular to the sheet conveying direction, the sheet is shifted in the width direction in the second discharge section 40b to perform jog discharge. be able to.

The post-processing unit 70 is a unit that performs post-processing such as binding processing on the sheets received from the relay conveying unit 60 . The post-processing unit of the present embodiment is equipped with a sheet binding processing mechanism that aligns and accumulates a plurality of conveyed sheets to form a sheet bundle and binds the sheet bundle.

In this embodiment, a configuration in which the intermediate transport unit 60 is interposed between the image forming apparatus 101 and the post-processing unit 70 will be described, but the post-processing unit 70 may be directly connected to the image forming apparatus 101 . In other words, the post-processing unit 70 can function as a processing device even in a single unit that is not combined with the relay transport unit 60 . The post-processing unit 70 is also an example of a sheet stacking device that stacks sheets on which images have been formed by the image forming apparatus 101, regardless of whether or not it has a function of performing post-processing on the sheets.

The configuration of the post-processing unit 70 as a sheet stacking device will be described with reference to FIG. The post-processing unit 70 includes a sheet supply port 72 as a receiving portion, a conveying roller 80 as a conveying means, a conveying path P5 as a route, a discharge roller 73 as a first discharge means, and discharge by the discharge roller 73 in a unit housing 71 . A processing tray 74 as a first stacking unit capable of stacking sheets, a sheet carrying-in member 75, a stapling processing unit 76 as a processing unit, a sheet edge regulation member 77, a width alignment member 79, and a bundle as a second discharge unit. A vertically movable stack tray 171 is provided on the opposite side of the sheet supply port 72 in which the discharge member 78 is stored. A blower device 90, which will be described later, is provided between the conveying roller 80 and the discharge roller 73 with respect to the sheet conveying direction on the conveying path P5. Further, a sheet existence sensor 55 is provided adjacent to the downstream side of the conveying roller 80 with respect to the sheet conveying direction of the conveying path P5. The sheet presence/absence sensor 55 is composed of, for example, an optical sensor, and is capable of detecting passage of the leading edge of the sheet or passage of the trailing edge of the sheet.

A sheet supply port 72 receives sheets from the image forming apparatus 101 . The conveying path P5 is a path between the sheet supply port 72 and the discharge roller 73, and has a flat bottom surface on the conveying roller 80 side. The conveying roller 80 is provided on the conveying path P<b>5 and conveys the sheet received from the sheet supply port 72 to the discharge roller 73 . In this embodiment, only the conveying roller 80 is provided as a conveying means between the discharge roller 73 and the sheet supply port 72 on the conveying path P5. That is, the conveying roller 80 is the most upstream conveying means in the sheet conveying direction of the conveying means, and the most downstream conveying means in the sheet conveying direction. It is a means of transportation.

The stack tray 171 has an upstream end in the sheet conveying direction by the bundle discharging member 78 arranged vertically below the downstream end in the conveying direction of the processing tray 74 , and is conveyed from the processing tray 74 by the bundle discharging member 78 . It is possible to load sheets that have been printed. The stack tray 171 can stack sheets discharged from the processing tray 74 by the bundle discharging member 78 .

The sheet carrying-in member 75 is composed of a paddle 75a and a knurled belt 75b as moving means, and the trailing edge of the sheet on the processing tray 74 (the upstream end in the conveying direction of the sheet conveyed by the discharge rollers 73) serves as a regulating means. is a member for conveying the sheet in the direction in which it abuts against the sheet end regulating member 77 . The knurled belt 75b is composed of a pair of rotating bodies arranged in the width direction orthogonal to the sheet conveying direction (see FIG. 5B). That is, the sheet edge regulating member 77 can regulate the edges of the sheets stacked on the processing tray 74 . Further, the knurled belt 75 b contacts the upper surface of the sheet placed on the processing tray 74 and moves the sheet so that the edge of the sheet hits the sheet edge regulating member 77 .

A sheet received from the image forming apparatus 101 via the relay conveying unit 60 and the sheet supply port 72 is conveyed by the discharge roller 73 and discharged to the processing tray 74 to be placed thereon. At this time, the paddle 75 a and the knurled belt 75 b convey the sheet in a direction opposite to the conveying direction of the discharge roller 73 , and the edge of the sheet hits the sheet edge regulating member 77 . The sheet end regulating member 77 is positioned at the upstream end of the processing tray 74 with respect to the sheet discharging direction by a bundle discharging member 78 to be described later, and can regulate the upstream end of the sheets placed on the processing tray 74 . The paddle 75a and the knurled belt 75b are configured to be movable between a retracted position away from the sheet and an operating position where they rotate in contact with the sheet. to convey.

The width aligning member 79 is composed of a pair of aligning members that are movable in the sheet width direction in the post-processing unit 70 (the direction intersecting with the sheet discharging direction by the bundle discharging member 78 (orthogonal direction in this embodiment)). and regulates the edge position of the sheet placed on the processing tray 74 in the sheet width direction. The width alignment member 79 moves between a retracted position spaced apart from the side edge of the sheet (edge in the sheet width direction) and an operating position corresponding to a target position (alignment position) when aligning the sheet in the sheet width direction. configured to be movable. At least one of the width aligning members 79 aligns the sheet discharged onto the processing tray 74 to the aligning position by moving from the retracted position to the operating position while contacting the side edge of the sheet. It should be noted that it is not always necessary to move the aligning members on both sides. The aligning operation in the sheet width direction may be performed with respect to . The other aligning member does not need to move in contact with the edge in the width direction of the sheet. The sheet width matching operation is possible by providing it.

The stapling unit 76 performs a stapling process on the sheet bundle aligned and accumulated on the processing tray 74 in the sheet conveying direction and the sheet width direction. That is, the stapling processing unit 76 processes the sheet bundle SB made up of a plurality of sheets stacked on the processing tray 74 . The stapling processing unit 76 is configured to be movable in the sheet width direction, and can perform stapling processing at a predetermined position of the corner portion of the sheet bundle and the edge of the sheet that contacts the sheet edge regulating member 77 . In this embodiment, a staple binding mechanism using staples is employed, but a stapleless binding mechanism that does not use staples may be employed, or the staple binding mechanism and the stapleless binding mechanism may be rearranged separately. They are provided on the front side (the front side of the image forming system 100, the front side in FIG. 1) and the rear side (the back side in FIG. 1) of the processing unit 70, and staple binding and stapleless binding are provided according to user settings. may be switched.

The bundle discharging member 78 is driven by the discharging member driving portion M6 (see FIG. 3), and pushes the trailing edge of the sheet bundle, thereby conveying the sheet bundle stacked on the processing tray 74 to the stack tray 171 and discharging it. . That is, the bundle discharge member 78 conveys the sheet bundle SB processed by the stapling unit 76 from the processing tray 74 to the stack tray 171 . The bundle discharge member 78 is retracted below the processing tray 74 until the sheet bundle is formed, and is retracted after the sheet bundle is formed on the processing tray 74 (or after the binding process is performed when the binding process is performed). ), and moves along the guide member 78 a to come into contact with the trailing edge of the sheet bundle and push the sheet bundle toward the stack tray 171 . Note that the bundle discharging member 78 can discharge a sheet bundle that is not stapled as well as the stapled sheet bundle as described above.

4A to 4D show the basic procedure of stapling processing by the post-processing unit 70. FIG. As shown in FIG. 4A , the sheet S is transferred from the relay conveying unit 60 to the post-processing unit 70 . As shown in FIG. 4B, the sheet S is discharged to the processing tray 74 by the discharge rollers 73, and the paddle 75a and the knurled belt 75b are lowered to the operating position and come into contact with the sheet S in sequence. As shown in FIG. 4C, the sheet S is moved toward the sheet edge regulating member 77. As shown in FIG. The sheet S that has been aligned in the conveying direction by contacting the sheet edge regulating member 77 is aligned in the sheet width direction by the width alignment member 79 . Such an aligning operation is repeated each time one sheet S is discharged, and when the number of sheets to form a sheet bundle are aligned and accumulated, the stapling processing section 76 performs a predetermined binding process for the sheet bundle. Staple position. After that, as shown in FIG. 4D, the bundle discharging member 78 comes into contact with the trailing edge of the sheet bundle SB and pushes the sheet bundle SB onto the stack tray 171. Then, as shown in FIG.

The details of the configuration of the discharge roller 73, the processing tray 74, the sheet introduction member 75, the stapling processing unit 76, the sheet edge regulation member 77, the width alignment member 79, and the bundle discharge member 78 described so far are described in, for example, Japanese Unexamined Patent Application Publication No. 2015. -16970, etc., and various post-processing units such as not only staple binding, but also stapleless binding, punching (punching holes), and folding can be applied. Also, the sheets can be shifted in the sheet width direction and discharged to the stack tray 171 without performing the binding process, and this can also be included in post-processing. If the sheet is to be shifted in the width direction, it can be achieved by changing the alignment position of the width alignment member 79 or by changing the sheet discharge position by means of a mechanism for shifting the discharge roller 73 in the sheet width direction.

As shown in FIG. 1 , the post-processing unit 70 (and the relay transport unit 60 ) of this embodiment is installed on the table 50 beside the image forming apparatus 101 . The pedestal 50 includes an installation portion 51 , leg portions 52 , and an opening 53 , and is fixed by hooking a hook member 54 provided on the side of the image forming apparatus 101 to the opening 53 . The installation portion 51 is provided with a slide rail (not shown), and the post-processing unit 70 is configured to be slidable in the horizontal direction in FIG. By separating the post-processing unit 70 (and the relay conveying unit 60 ) from the image forming apparatus 101 , jam clearing processing can be performed when a sheet is jammed.

When the post-processing unit 70 moves to the front end side of the installation portion 51 , a counterclockwise force acts on the mounting table 50 , but the leg portion 52 engages the hook member 54 and the side portion 1 c of the image forming apparatus 101 . Since the stand 50 is supported by the support, the stand 50 does not fall down.

[Emission configuration]
In this embodiment, a plurality of discharge units for discharging processed sheets are provided. As described above, the first discharge section 40a discharges the sheet on which the image has been formed by the image forming section 21 face-down straight, or reverses the front and back of the sheet in the sheet reversing path P3 and discharges it face-up. It is the discharge part. The first discharge section 40 a is a so-called in-body discharge section of the image forming apparatus 101 and is composed of a space defined by the standing surface 1 a of the apparatus housing 1 , the ceiling surface 1 b and the mounting surface 41 .

The second discharge section 40b is a discharge section using the sheet mounting surface 71a on the upper surface of the unit housing of the post-processing unit 70, and discharges the sheet on which the image forming process has been performed by the image forming section 21 straight face up or inverting the sheet. In pass P3, the front and back of the sheet are reversed and discharged face down. In other words, the first discharge section 40a and the second discharge section 40b can be discharged by the user's setting. However, considering productivity, the first discharge section 40a is used in the case of face-down, and the first discharge section 40a is used in the case of face-up. In this case, it is desirable to discharge to the second discharge section 40b.

Further, it is determined whether to discharge to the first discharge section 40a or to the second discharge section 40b depending on the amount of ink adhered to the sheet by the image forming process by the image forming section 21 (for example, based on the information regarding the image ratio described later). Distribution is also possible. For example, when the image ratio is low, there is no need to dry the ink adhering to the sheet. Therefore, as described above, the sheet is discharged as it is to the first discharge section 40a in the case of face-down and to the second discharge section 40b in the case of face-up as described above. . However, when the image ratio is high, it is necessary to dry the ink adhering to the sheet. Therefore, the sheet is once conveyed to the sheet reversing path P3 to gain time until the sheet is discharged, thereby drying the sheet. After the sheet is conveyed through the sheet reversing path P3, the face-up sheet is discharged to the first discharge section 40a, and the face-down sheet is discharged to the second discharge section 40b. If a drying member such as a fan is provided in the sheet reversing path P3, the drying effect can be further enhanced.

The third discharge portion 40c is the stack tray 171 of the post-processing unit 70, and the sheets post-processed by the post-processing unit 70 are discharged. The stack tray 171 is configured to be able to move up and down, and moves up and down according to the sheet stacking amount. In addition, since the post-processing unit 70 of the present embodiment has a mechanism for shifting the sheets in the width direction, the sheets are discharged on the stack tray 171 while being shifted in the width direction without stapling. can be made

It should be noted that, in the present embodiment, the post-processing unit 70 performs processing described later based on the information regarding the image ratio. However, for example, a sheet on which an image with a high image ratio exceeding the limit of the range suitable for processing by the post-processing unit 70 (for example, a sheet on which a dark-colored full-surface solid image or the like is printed) is first discharged. You may make it discharge|eject to the part 40a or the 2nd discharge|emission part 40b.

In addition, when the post-processing is performed by the post-processing unit 70, the productivity is lowered as compared with the straight discharge. Therefore, even when the productivity-oriented mode is executed, the sheet may be discharged to the first discharge section 40a or the second discharge section 40b.

[Control configuration]
FIG. 3 is a diagram showing the control configuration of the image forming system 100 of this embodiment. The image forming apparatus 101 and the sheet processing apparatus 102 have control CPUs 81 and 87, respectively, and can exchange information with each other. The first control CPU 81 of the image forming apparatus 101 is connected to the image formation control section 82 , the first drive control section 83 , the reading control section 84 and the first signal control section 85 . The reading control section 84 acquires the image data read by the image reading section 33 of the image reading unit 30 and sends it to the first control CPU 81 as print data. The first control CPU 81 sends the print data received from the read control unit 84 to the image formation control unit 82, and the image formation control unit 82 controls the image formation unit 21 to perform image formation processing. In addition, the first control CPU 81 issues a command to the first drive control unit 83 according to input information (detection of the sheet edge, etc.) from various sensors connected to the first signal control unit 85, and controls the rollers for conveying the sheet. The sheet is conveyed by controlling the conveying driving motor and the switching member driving section. The first control CPU 81 is also connected to an input section 86 for inputting information such as print mode, discharge mode, and post-processing mode from the user, and controls each control section according to the input information. Mode information is transmitted to the second control CPU 87 of the sheet processing apparatus 102 .

An “image forming mode” and a “post-processing mode” are set from the input unit 86 . The image forming mode is set for color or monochrome printing, double-sided or single-sided printing, and image forming conditions such as sheet size, sheet type (sheet basis weight, material, etc.), number of copies to be printed, and enlarged or reduced printing. do. The "post-processing mode" is set to, for example, "printout mode", "stapling mode", "eco-binding mode", and "jog sorting mode". Note that the illustrated sheet processing apparatus 102 is provided with a "manual binding mode", in which the sheet bundle binding processing operation is performed off-line separately from the first control CPU 81 of the image forming apparatus 101. FIG.

The second control CPU 87 of the sheet processing apparatus 102 is provided in the post-processing unit 70 and controls not only the post-processing unit 70 but also the relay conveying unit 60 . The second control CPU 87 is connected to the second drive control section 88 and the second signal control section 89, and receives input information from various sensors connected to the second signal control section 89 (sheet edge detection by the sheet presence/absence sensor 55). unit detection, etc.), a command is issued to the second drive control unit 88, and the operation of the sheet processing apparatus 102 is controlled. The second drive control unit 88 operates, based on commands from the second control CPU 87 , a transport drive motor M<b>1 that drives the rollers that transport the sheet, and a switching motor that drives the switching member arranged in the path switching unit 61 of the relay transport unit 60 . The member driving unit M2 is controlled to convey the sheet. The second drive control unit 88 includes a staple driving unit M3 that drives the stapling processing unit 76, a width alignment driving unit M4 that drives the width alignment member 79, and a rake driving unit M5 that drives the paddle 75a and the knurled belt 75b. , a discharge member drive unit M6 for driving the bundle discharge member 78, and a fan drive motor M7 for driving a fan 91 of the blower device 90, which will be described later. Causes unit 70 to perform post-processing operations.

Also, the first control CPU 81 transfers to the second control CPU 87 data such as the post-processing mode, information on the number of sheets (the number of sheets to form a bundle), information on the number of copies, and sheet type information such as the size and thickness of sheets on which images are formed. . In addition, the first control CPU 81 transfers a job end signal to the second control CPU 87 each time the image forming process is completed. Further, in the present embodiment, the first control CPU 81 transfers print information, particularly information on the image ratio of the sheet (for example, ink ejection amount) to the second control CPU 87 . The print information includes image information read by the image reading unit 30, ink ejection amount calculated from the image information, and the like, in addition to information regarding the image ratio of the sheet.

Here, the “image ratio (printing ratio)” is the ratio of the area of the area where the image is formed to the area of the entire image-formable area of the sheet. For example, the image ratio is 100% for a full-surface solid image in which an image having the maximum density is formed in the entire area where the image forming unit 21 can form an image on the sheet. In the case of an inkjet image forming apparatus, if the image ratio is high, the amount of ink used to form an image on the sheet also increases. In the following description, the type of information regarding image ratios used for controlling operations based on image ratios is not particularly limited. Examples of information about the image ratio include a count value obtained by accumulating the amount of ink ejected in an inkjet method, and a count value (video count value) obtained by accumulating a signal specifying the presence or absence of a dot for each pixel in an electrophotographic method.

By the way, for example, when an image is formed by an inkjet method, if the image ratio is high, the moisture content of the sheet increases and the hardness decreases. In this case, the knurled belt 75b used to rake the sheet in the post-processing unit 70 may contact the sheet and rotate, thereby damaging the contact portion of the upper surface of the sheet. Therefore, if the knurled belt 75b contacts the image forming surface of the sheet, image defects may occur, and if the knurling belt 75b contacts the back side of the image forming surface of the sheet, the sheet itself may be damaged. Therefore, in the present embodiment, by providing an air blower that blows air to dry the sheet before the knurled belt 75b abuts on the sheet, damage to the sheet surface by the knurled belt 75b is suppressed even when the water content of the sheet is high. I'm trying

[Blower]
Next, the blower device 90 as the blowing means, which is the characteristic configuration of the present embodiment, will be described in detail. As shown in FIG. 2, the blower device 90 has a fan 91 that blows air by rotation, and is arranged between the conveying roller 80 and the discharging roller 73 with respect to the sheet conveying direction on the conveying path P5.

As shown in FIGS. 5A and 5B, the blower device 90 rotates between a pair of rotating bodies forming the knurled belt 75b in the width direction (horizontal direction in FIG. 5) orthogonal to the sheet conveying direction D1. are placed in In FIG. 5A, an area Ar1 is a range in which air from the air blower 90 reaches the sheet, that is, a range in which the sheet is dried by the air blower 90 . As shown in FIG. 5B, when the sheet dried in the area Ar1 by the blower 90 is placed on the processing tray 74 and brought into contact with the sheet edge regulating member 77, the dried area Ar1 is knurled. It overlaps the contact portion between the belt 75b and the sheet. That is, the air blower 90 can blow air to the area Ar1 including the contact portion between the knurled belt 75b and the sheet S in the width direction before the sheet S is discharged onto the processing tray 74 by the discharge rollers 73 . Therefore, the fan 91 dries the area Ar<b>1 where the knurled belt 75 b contacts the sheet before the sheet is discharged onto the processing tray 74 by the discharge rollers 73 .

The fan 91 is driven by a fan drive motor M7 (see FIG. 3) based on a command signal from the second control CPU 87 (see FIG. 3), and when driven, draws in air from the upper side of the unit housing 71 and removes the seat below. Blow out towards. In this embodiment, the fan 91 blows air in a direction substantially perpendicular to the conveying path P5. Further, the center of the fan 91 is preferably positioned at the center of the contact portion between the knurled belt 75b and the sheet S. Incidentally, the air blowing direction of the fan 91 can be set as appropriate, and the air may be directed obliquely in an appropriate direction instead of being perpendicular to the upper side of the conveying path P5 as in the present embodiment.

The operation of the blower 90 will be described with reference to FIGS. 6(a) and 6(b). For example, when a sheet on which an image is formed on only one side with a high image ratio by the image forming apparatus 101 is conveyed to the post-processing unit 70, as shown in FIG. transport. The leading edge of the sheet S passes the sheet presence/absence sensor 55 , is further conveyed, and is nipped by the discharge rollers 73 . Here, when the air blowing range from the air blowing device 90 is positioned in the drying area Ar1 of the sheet S, the discharging roller 73 and the conveying roller 80 are stopped. At this time, the sheet S is nipped by both the discharge roller 73 and the transport roller 80 . By rotating the fan 91, air is blown to the area Ar1 of the sheet S to dry it. Therefore, after that, the sheet S is discharged from the discharge roller 73, the knurled belt 75b abuts on the upper surface of the sheet S in the processing tray 74 and rakes in the sheet. Damage to S is suppressed. As for the timing of stopping the conveyance of the sheet S, for example, after the sheet presence/absence sensor 55 detects that the leading edge of the sheet has passed, the sheet is stopped after being conveyed by a predetermined amount, or after being conveyed for a predetermined period of time. can be done. Conveyance of a predetermined amount is performed by, for example, rotating the discharge roller 73 a predetermined number of times. However, it goes without saying that the timing for stopping the conveyance of the sheet S is not limited to this example.

Further, for example, when a sheet on which images are formed on both sides at a high image ratio by the image forming apparatus 101 is conveyed to the post-processing unit 70, the sheet S is conveyed from the conveying roller 80 to the conveying path as shown in FIG. 6B. Transport to P5. The leading edge of the sheet S passes the sheet presence/absence sensor 55, is further conveyed, and is nipped by the discharge rollers 73, but continues to be conveyed. After the trailing edge of the sheet S passes through the conveying roller 80 and the sheet presence/absence sensor 55 and is positioned directly below the air blower 90, the discharge roller 73 is stopped and the fan 91 is rotated. That is, when images are formed on both sides of a sheet received from the sheet supply port 72 (see FIG. 2), the discharge roller 73 is arranged such that the upstream end of the sheet is positioned between the conveyance roller 80 and the discharge roller 73 in the sheet conveying direction D1. When positioned in between, the sheet is stopped for a predetermined time, and the air blower 90 blows air to the stopped sheet. In this embodiment, the center of the fan 91 is positioned to face the rear end of the sheet. As a result, the air blown from the blower 90 not only dries the upper surface of the rear portion of the sheet S, but also enters between the rear end of the sheet S and the planar bottom surface of the conveying path P5, causing the rear portion of the sheet S to flutter. , the underside of the rear of the sheet S can also be dried. Therefore, even in the case of a sheet on which images are formed on both sides, the area Ar1 can be dried, so damage to the sheet S caused by the knurled belt 75b coming into contact with the upper surface of the sheet S and scratching the sheet can be suppressed. . In this embodiment, the blowing direction of the fan 91 is substantially perpendicular to the conveying path P5. , air is likely to enter from the rear end of the sheet S to the lower surface side.

Here, if the knurled belt 75b is constantly in contact with the sheets stacked on the processing tray 74, the possibility of damaging the sheets increases. Therefore, in this embodiment, when the first sheet is to be scraped into the processing tray 74, only the paddle 75a is operated and the knurled belt 75b is not rotated. Then, when raking the second sheet into the processing tray 74, the knurled belt 75b is rotated a predetermined number of times. Such an operation can suppress damage to the sheet.

In this embodiment, the degree of drying is changed according to the image ratio of the sheet S. FIG. As a result, it is possible to suppress the occurrence of downtime due to drying even sheets that do not need to be dried, and to suppress energy consumption.

In the present embodiment, the threshold value of the image ratio is set to 70%, and when the image ratio is a first value (for example, a value less than 70%), the conveying of the sheet S is not stopped and the blower device Do not blow air from 90. On the other hand, when the image ratio is a second value larger than the first value (for example, a value of 70% or more), the sheet S stops being conveyed, and the air blower 90 blows air. That is, when the image ratio is the first value, the discharge roller 73 discharges the sheet S to the processing tray 74 without stopping the sheet S while the air blower 90 blows or does not blow air to the sheet S. When the ratio is the second value, the sheet S is stopped for a predetermined time while the air blower 90 blows air onto the sheet S. However, the present invention is not limited to this. For example, when the image ratio is the first value, the discharge roller 73 sets the discharge speed of the sheet S to the first value while the air blower 90 blows air onto the sheet S or while it does not blow air. When the image ratio is the second value, the discharge speed of the sheet S while the air blower 90 blows air to the sheet S is set to the second speed V2 which is lower than the first speed V1. may In this case also, the degree of drying can be varied by changing the conveying speed, and damage to the sheet surface caused by the knurled belt 75b that moves the sheet in contact with the sheet surface can be suppressed even when the water content of the sheet S is high. .

Alternatively, the degree of drying may be varied not only by stopping the conveyance of the sheet S or changing the conveying speed, but also by stopping air blowing or changing the amount of air (air velocity), for example. For example, when the image ratio is the first value, the blower 90 does not blow air to the sheet S before being discharged onto the processing tray 74 by the discharge rollers 73, and the image ratio is the second value. In this case, the discharge roller 73 can blow air to the sheet S before being discharged to the processing tray 74 . Alternatively, when the image ratio is the first value, the air blower 90 sets the air volume to be blown to the sheet S before being discharged onto the processing tray 74 by the discharge roller 73 as the first air volume F1, and the image ratio is is the second value, the amount of air blown onto the sheet S before being discharged onto the processing tray 74 by the discharge roller 73 can be set to a second air amount F2 larger than the first air amount. In these cases as well, the degree of drying can be made different, and damage to the sheet surface caused by the knurled belt 75b that moves the sheet in contact with the sheet surface can be suppressed even when the sheet S has a high water content. In this embodiment, since the shape of the flow path around the blower device 90 does not change, the air volume correlates with the wind speed. Therefore, the second control CPU 87 changes the air volume only by changing the rotational speed of the fan drive motor M7 of the fan 91. FIG.

Next, a procedure for performing air blowing processing using the air blower 90 after image formation in the image forming system 100 of the present embodiment will be described in detail with reference to the flowchart shown in FIG. Here, a case where the image forming apparatus 101 forms an image on only one side of a sheet will be described. Further, here, when the image ratio is large, air is blown from the blower 90 and sheet conveyance is temporarily stopped, and when the image ratio is small, air blow from the blower 90 is stopped and sheet conveyance is not stopped. describes the case.

After the image formation in the image forming apparatus 101 is started, delivery of the image-formed sheet from the relay conveying unit 60 to the post-processing unit 70 is started (step S1). At this time, the second control CPU 87 of the sheet processing apparatus 102 acquires the image ratio of each transferred sheet from the image forming apparatus 101 (step S2).

The second control CPU 87 determines whether or not the obtained image ratio is less than 70% (step S3). When the second control CPU 87 determines that the image ratio is not less than 70% (NO in step S3), it determines that the image ratio is large. The leading edge of the sheet S passes the conveying roller 80 (step S4), and subsequently the sheet presence/absence sensor 55 is turned on (step S5). When the second control CPU 87 detects that the sheet presence/absence sensor 55 is turned on, the second control CPU 87 rotates the discharge roller 73 and the conveying roller 80 a predetermined number of times to convey the sheet S by a predetermined amount, and stops conveying (step S6). . At this time, the sheet S is nipped by both the discharge roller 73 and the conveying roller 80, and the air blown range from the air blower 90 faces the drying area Ar1 of the sheet S (see FIG. 6A).

The second control CPU 87 starts air blowing by the air blower 90 (step S7), and dries the area Ar1 of the sheet S (see FIG. 5A). The second control CPU 87 uses a timer to stop blowing air from the air blower 90 after a predetermined time, and restarts the conveyance of the discharge roller 73 and the conveyance roller 80 (step S8). After that, the trailing edge of the sheet S passes through the conveying roller 80 and the discharge roller 73, whereby the sheet S is discharged from the discharge roller 73 (step S9).

On the other hand, when the second control CPU 87 determines that the image ratio is less than 70% (YES in step S3), it determines that the image ratio is small. The leading edge of the sheet S passes the conveying roller 80 (step S10), and subsequently the sheet presence/absence sensor 55 is turned on (step S11). In this case, unlike the case where the image ratio is large, the sheet S continues to be conveyed without being stopped (step S12), and the sheet S is discharged from the discharge roller 73 (step S9).

As described above, according to the sheet processing apparatus 102 of the present embodiment, the blower device 90 moves the knurled belt 75b and the sheet S in the width direction before being discharged onto the processing tray 74 by the discharge rollers 73. It is possible to blow air to the area Ar1 including the abutting portion of the . Therefore, the fan 91 dries the area Ar<b>1 where the knurled belt 75 b contacts the sheet S before the sheet is discharged onto the processing tray 74 by the discharge rollers 73 . Therefore, even when the water content of the sheet S is high, damage to the sheet surface caused by the knurled belt 75b that contacts the sheet surface and moves the sheet can be suppressed.

Further, according to the sheet processing apparatus 102 of the present embodiment, the blower device 90 is arranged between a pair of rotating bodies forming the knurled belt 75b with respect to the width direction (horizontal direction in FIG. 5). Therefore, compared to the case where the air blower 90 is provided for each of the pair of rotating bodies, drying can be efficiently performed with only one air blower 90 . That is, since the two functions can be shared, an increase in the number of parts can be suppressed.

Further, according to the sheet processing apparatus 102 of the present embodiment, when images with a high image ratio are formed on both sides of the sheet S, as shown in FIG. , the air blower 90 blows air from the trailing end of the sheet S to the flat bottom surface of the conveying path P5 to dry both sides of the rear portion of the sheet S. can be done. Therefore, compared to the case where the air blower for drying the upper surface of the sheet S and the air blower for drying the lower surface of the sheet S are provided separately, an increase in the number of parts can be suppressed.

<Other embodiments>
In the sheet processing apparatus 102 according to each of the above-described embodiments, the case where the flat bottom surface is provided on the conveying roller 80 side of the conveying path P5 has been described, but the present invention is not limited to this. For example, by providing a convex portion such as a concave portion or a rib on the bottom surface of the conveying path P5, it is possible to make it easier for air to enter the lower side of the sheet S that is not nipped by the conveying rollers 80 . In this case, for example, even if the angle of the fan 91 is set perpendicular to the sheet S, both sides of the rear portion of the sheet S can be dried by flapping the rear portion of the sheet S.

Further, in the sheet processing apparatus 102 in each of the above-described embodiments, when the image ratio is large, air is blown from the blower 90 and sheet conveyance is temporarily stopped, and when the image ratio is small, air is blown from the blower 90. is stopped and sheet conveyance is not stopped, but the present invention is not limited to this. For example, when the image ratio is large, air is blown from the blower 90 and the sheet is conveyed at a high first speed V1, and when the image ratio is small, the blow from the blower 90 is stopped and the sheet is conveyed. may be performed at a lower second speed V2. In this case also, the degree of drying can be varied by changing the conveying speed, and damage to the sheet surface caused by the knurled belt 75b that moves the sheet in contact with the sheet surface can be suppressed even when the water content of the sheet S is high. .

A procedure for executing the blowing process in this case will be described in detail along the flowchart shown in FIG. In the flowchart shown in FIG. 8, the same steps as those in the flowchart shown in FIG. 7 are given the same step numbers, and detailed description thereof will be omitted. When the second control CPU 87 determines that the image ratio is not less than 70% (NO in step S3), it determines that the image ratio is large. The leading edge of the sheet S passes the conveying roller 80 (step S4), and subsequently the sheet presence/absence sensor 55 is turned on (step S5). When the second control CPU 87 detects that the sheet presence/absence sensor 55 is turned on, the discharge roller 73 and the conveying roller 80 set the conveying speed to a second speed V2, which is lower than the first speed V1, and conveys the sheet (step S20). The second control CPU 87 starts air blowing by the air blower 90 (step S7), dries the area Ar1 (see FIG. 5A) of the sheet S, and uses a timer to blow air from the air blower 90 after a predetermined time. is stopped (step S21). After that, the trailing edge of the sheet S passes through the conveying roller 80 and the discharge roller 73, whereby the sheet S is discharged from the discharge roller 73 (step S9). On the other hand, when the second control CPU 87 determines that the image ratio is less than 70% (YES in step S3), the second control CPU 87 determines that the image ratio is small, and reduces the transport speed by the discharge roller 73 and the transport roller 80 to the first speed. The sheet is conveyed at speed V1 (step S22).

Further, in the sheet processing apparatus 102 in each of the above-described embodiments, the case where the image ratio is transmitted from the first control CPU 81 of the image forming apparatus 101 to the second control CPU 87 of the sheet processing apparatus 102 has been described. Not limited. For example, the image forming apparatus 101 or the sheet processing apparatus 102 may be provided with an image sensor such as a CIS that reads an image on a sheet after image formation, and the image ratio may be obtained based on the value read by this image sensor. . In this case, for example, the image ratio can be obtained even if the first control CPU 81 does not have information regarding the image ratio, or the image ratio based on the actually formed image can be obtained.

Further, in the sheet processing apparatus 102 according to each of the above-described embodiments, the case where 70% is applied as the threshold for the image ratio and the air volume is varied based on whether the image ratio is less than 70% has been described. is not limited to For example, the threshold is not limited to 70%, and may be an appropriate value between 60% and 80%, for example. Alternatively, the threshold is not limited to one. For example, two large and small thresholds are provided, and the image ratio is divided into three stages such as a case where the image ratio is smaller than a small threshold, a case where it is between two thresholds, and a case where it is larger than a large threshold. Different air volumes may be set for each of them. The number of steps may be four or more, or may be changed linearly steplessly.

It should be noted that part of the processing executed by the second control CPU 87 in the above embodiment is carried out in a housing other than the housing in which the first stacking unit is mounted, such as the first control CPU 81 of the image forming apparatus 101. A processor may be responsible. In particular, the first control CPU 81 of the image forming apparatus 101 calculates the amount of air blown from the blower 90 based on the information regarding the image ratio, and transmits the result to the second control CPU 87. A form in which the information is not sent to the control CPU 87 may be used. The ``sheet stacking device'' in such a form includes a device body having a mechanical configuration (processing tray 74, stack tray 171, etc.) for stacking sheets, and an apparatus body electrically connected to the device body. It refers to those provided with elements (processors, storage devices, etc.) that make up a control circuit for operating the main body.

In addition, the present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device execute the program. It can also be realized by a process of reading and executing. It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

21... Image forming unit 70... Post-processing unit (sheet stacking device) 72... Sheet supply port (receiving part) 73... Discharge roller (first discharge means) 74... Processing tray (first stack part) 75b ... knurled belt (moving means), 76 ... stapling unit (processing means), 77 ... sheet edge regulating member (regulating means), 78 ... bundle discharging member (second discharging means), 80 ... conveying roller (conveying means) , 90... Air blower (air blowing means), 100... Image forming system, 101... Image forming apparatus, 171... Stack tray (second stacking unit), S... Sheet.

Claims (11)

A sheet stacking device for stacking image- formed sheets having at least an image formed on the upper surface thereof by an image forming device,
a receiving unit that receives the image-formed sheet from the image forming apparatus;
a first discharging means for discharging the image- formed sheet received by the receiving section in a discharging direction ;
a first stacking section capable of stacking the image-formed sheet discharged by the first discharging means;
a regulating means capable of regulating a position of an end portion of the image-formed sheet stacked on the first stacking portion;
moving means for contacting the upper surface of the image-formed sheet stacked on the first stacking section and moving the sheet so that the end portion of the sheet abuts against the regulating means;
a second discharging means for discharging the image-formed sheets stacked on the first stacking section;
a second stacking section capable of stacking the image-formed sheet discharged from the first stacking section by the second discharging means;
a blower capable of blowing air onto the upper surface of the image-formed sheet before being stacked on the first stacking unit;
A sheet stacking device characterized by: The air blowing means, for the image-formed sheets before being stacked on the first stacking section,
In a width direction perpendicular to the discharge direction and along the surface of the image formed sheet stacked on the first stacking unit, the moving means moves the image formed sheet stacked on the first stacking unit. Configured to be able to blow air to a range including the abutting contact point,
2. The sheet stacking device according to claim 1, wherein: conveying means provided on a path through which the image-formed sheet from the receiving part to the first discharging means passes, and conveying the image-formed sheet received from the receiving part to the first discharging means in a conveying direction; further prepared,
The air blowing means is arranged in the conveying direction between the first discharging means and the conveying means arranged on the most upstream side in the conveying direction,
3. The sheet stacking device according to claim 1, wherein: conveying means provided on a path through which the image-formed sheet from the receiving part to the first discharging means passes, and conveying the image-formed sheet received from the receiving part to the first discharging means in a conveying direction; further prepared,
When the image-formed sheet received from the receiving section has images formed on both sides, the upstream end in the conveying direction of the image-formed sheet received from the receiving section is arranged on the most downstream side in the conveying direction. and the first discharging means stops discharging the image-formed sheet for a predetermined time, and the air blowing means stops discharging the first discharging means. blowing air onto the imaged sheet;
3. The sheet stacking device according to claim 1 , wherein: The moving means has a pair of rotating bodies arranged side by side in a width direction perpendicular to the discharge direction and along the surface of the image-formed sheet stacked on the first stacking section,
The air blowing means is arranged between the pair of rotating bodies in the width direction,
The sheet stacking device according to any one of claims 1 to 4 , characterized in that: When the image ratio of the image formed on the image-formed sheet by the image forming apparatus is a first value, the first discharging means blows air onto the upper surface of the image-formed sheet, or When the sheet on which the image has been formed is discharged to the first stacking unit without being stopped in a state in which air is not blown, and the image ratio is a second value larger than the first value, the first discharging means stopping discharge of the image-formed sheet for a predetermined time in a state in which air blowing means blows air onto the upper surface of the image-formed sheet;
The sheet stacking device according to any one of claims 1 to 5, characterized in that: When the image ratio of the image formed on the image-formed sheet by the image forming apparatus is a first value, the first discharging means blows air onto the upper surface of the image-formed sheet, or A discharge speed for discharging the sheet on which the image has been formed without blowing air is defined as a first speed, and when the image ratio is a second value larger than the first value, the first discharge means is the blower means. blowing air onto the upper surface of the image-formed sheet, and setting a discharge speed for discharging the image-formed sheet to a second speed that is lower than the first speed;
The sheet stacking device according to any one of claims 1 to 5, characterized in that: When the image ratio of the image formed on the image-formed sheet by the image forming apparatus is a first value, the air blowing means moves the upper surface of the image-formed sheet before being stacked on the first stacking section. When the image ratio is a second value larger than the first value, the air blowing means controls the image formed image before being discharged to the first stacking section by the first discharging means. to blow air onto the top surface of the sheet,
The sheet stacking device according to any one of claims 1 to 7, characterized in that: When the image ratio of the image formed on the image-formed sheet by the image forming apparatus is a first value, the air blowing means moves the upper surface of the image-formed sheet before being stacked on the first stacking section. When the image ratio is a second value larger than the first value, the air blower blows the image formed image before being stacked on the first stacking unit. setting the air volume blown to the upper surface of the sheet to a second air volume larger than the first air volume;
The sheet stacking device according to any one of claims 1 to 7 , characterized in that: a processing unit for processing a sheet bundle composed of the plurality of image-formed sheets stacked on the first stacking unit;
The second discharging means discharges the sheet bundle processed by the processing means from the first stacking section to the second stacking section.
The sheet stacking device according to any one of claims 1 to 9, characterized in that: an image forming apparatus including an image forming unit that forms an image on a sheet;
The sheet stacking device according to any one of claims 1 to 10, which stacks the image-formed sheets on which images are formed by the image forming device,
An image forming system characterized by:

Images