JP7780283B2 - Sheet processing apparatus and image forming apparatus - Google Patents

Description

The present invention relates to a sheet processing device that binds a stack of sheets, and an image forming apparatus equipped with such a sheet processing device.

Conventionally, image forming devices such as copiers, laser beam printers, facsimiles, and all-in-one machines are equipped with sheet processing devices that perform sheet processing such as binding on sheets on which images have been formed.

Image forming devices are known that are equipped with both a staple binding means that uses metal staples such as staples to bind multiple sheets, and a stapleless binding means that processes the sheets themselves to bind them without using metal staples (see, for example, Patent Document 1).

Furthermore, the image forming apparatus described in Patent Document 1 has a configuration in which a sheet processing device that performs post-processing on sheets on which images have been formed is located in the internal space defined between the image forming unit and the image reading unit above it.

JP 2014-61964 A

The dimensions and volume of the internal space of an image forming device are usually limited in order to make the entire device compact. In particular, when stapling near the corner on the upstream side and rear side in the sheet transport direction, there is a risk that the staple binding means and stapleless binding means will interfere with each other in the narrow space.

The present invention was made in consideration of the above-mentioned problems with the conventional technology, and aims to make it possible to make a sheet processing device that performs both staple binding and stapleless binding more compact.

A further object of the present invention is to provide an image forming apparatus that is equipped with a compact sheet processing device capable of both staple binding and stapleless binding within the internal space of the body, thereby making the entire apparatus compact.

The sheet processing apparatus of the present invention comprises:
A sheet processing apparatus that performs binding processing on a sheet bundle,
a tray for stacking the conveyed sheets one by one to form a sheet bundle;
a plurality of abutting means arranged in front and rear directions of the sheet processing apparatus, against which the edge of the sheet on the tray abuts;
a shift unit that shifts the sheet that has been abutted against the abutting means in the front-to-rear direction;
a stapler configured to be able to staple a corner portion of the sheet stack abutted against the abutting means and on the rear side in the front-rear direction of the sheet stack;
a stapleless binding unit that is provided on the rear side of the abutting means and is configured to be able to perform stapleless binding on a corner portion of the sheet bundle that is abutted against the abutting means and on the rear side,
The abutting means is configured such that an abutting member disposed at the innermost side in the front-rear direction is movable in the front-rear direction on the front side of the stapleless binding unit in the front-rear direction,
When the stapler performs the staple processing on the corner portion of a sheet stack consisting of predetermined sheets, the abutment member is moved to the rear side and the sheets are shifted to the front side by the shift unit, so that the staple processing is performed on the corner portion of the sheet stack closer to the front side than the abutment member that has moved to the rear side .

In yet another aspect of the present invention, the image forming apparatus of the present invention comprises:
an image forming unit that forms an image on a sheet ;
an image reading unit disposed above the image forming unit;
an internal space defined between the image forming unit and the image reading unit;
a sheet processing unit that is mounted in the internal space of the body and that performs a binding process on a sheet stack made up of sheets on which images have been formed by the image forming unit ,
The sheet processing unit is characterized by comprising the sheet processing apparatus of the present invention described above.

The sheet processing device of the present invention has a compact overall configuration, and can perform binding processing on the corners of sheets using either the first binding means or the second binding means.

1 is a diagram showing the overall configuration of an image forming apparatus to which the present invention is applied; 1 is a diagram showing the overall configuration of a sheet processing apparatus according to the present invention; FIG. 3 is a plan view showing a main part of the sheet processing apparatus of FIG. 2 . 10A and 10B are perspective views showing the configuration and movement of a first sheet end regulating member. FIG. 4 is a perspective view showing the positional relationship between a first sheet end regulating member and a stapler. FIG. 10 is a perspective view of the first sheet end regulating member as viewed from the upstream side in the conveying direction. 1A to 1C are explanatory diagrams showing the sheet conveying operation of the sheet processing apparatus in order. 8A to 8C are explanatory diagrams showing the sheet conveying operation of the sheet processing apparatus in sequence following FIG. 7; 1A and 1B are explanatory diagrams showing the sheet binding process operation in sequence in the first embodiment; 10A and 10B are explanatory diagrams showing the binding processing operation in sequence following FIG. 9 . 11A and 11B are explanatory diagrams showing the binding process operation in sequence following FIG. 10 . 12A and 12B are explanatory diagrams showing the binding process operation in sequence following FIG. 11 . 10A and 10B are explanatory diagrams showing the sheet binding process operation in sequence in the second embodiment; 14A and 14B are explanatory diagrams showing the binding processing operation in sequence following FIG. 13 . 15A and 15B are explanatory diagrams showing the binding processing operation in sequence following FIG. 14 . FIG. 16 is an explanatory diagram showing the binding processing operation subsequent to FIG. 15 . 11A and 11B are explanatory diagrams showing the sheet binding process operation in sequence in the third embodiment. 18A and 18B are explanatory diagrams showing the binding processing operation in sequence following FIG. 17; 19A and 19B are explanatory diagrams showing the binding processing operation in sequence following FIG. 18 . 20A and 20B are explanatory diagrams showing the binding process operation in sequence following FIG. 19; 13A and 13B are explanatory diagrams showing the sheet binding process operation in sequence in a fourth embodiment. 22A and 22B are explanatory diagrams showing the binding process operation in sequence following FIG. 21 . 23A and 23B are explanatory diagrams showing the binding processing operation in sequence following FIG. 22; 24A and 24B are explanatory diagrams showing the binding processing operation in sequence following FIG. 23 . 25A and 25B are explanatory diagrams showing the binding processing operation following FIG. 24 .

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[Image forming apparatus]
1 shows the overall configuration of an image forming apparatus to which the present invention is applied, as seen from the front side. In this specification, the front side of the image forming apparatus in FIG. 1 will be referred to as the front side of the apparatus, and the back side will be referred to as the rear side of the apparatus.

The image forming apparatus in Figure 1 is composed of an image forming unit A, a sheet processing device B, an image reading unit C, and an automatic document feeder unit D. The sheet processing device B functions as a post-processing device for sheets on which images are formed by the image forming unit A. The image forming apparatus of this embodiment is a so-called internal discharge type, in which a large, U-shaped discharge space (internal space) is defined between the image forming unit A and the image reading unit C in Figure 1, and the sheet processing device B is disposed within this internal space.

Image forming unit A forms an image on a sheet based on the image data of the original image read by image reading unit C, and transports the image-formed sheet to sheet processing device B. As described below, sheet processing device B collates and stacks the sheets transported from image forming unit A, binds them, and then stores them in a stacking tray. In this specification, "sheet transport direction" refers to the direction in which sheets are transported from image forming unit A to sheet processing device B, and "sheet width direction" refers to a direction intersecting the sheet transport direction, and in this embodiment in particular, a direction perpendicular to the sheet transport direction.

[Image forming unit]
1, the image forming unit A is made up of a paper feed section 1, an image forming section 2, a paper discharge section 3, and a signal processing section (not shown), all of which are housed in a device housing 4. The paper feed section 1 is made up of cassettes 5 (in the illustrated embodiment, multiple cassettes 5a, 5b, and 5c) that store sheets. Each of the cassettes 5a to 5c contains a paper feed roller 6 that feeds out sheets, and a separation means (not shown) such as a separation claw or separation roller that separates sheets one by one, and is configured to be able to store sheets of different sizes.

The paper feed unit 1 has a paper feed path 7 that feeds sheets from cassette 5 to the image forming unit 2. The paper feed unit 1 unwinds sheets from cassettes 5a, 5b, and 5c that correspond to the size selected by the control unit, and feeds them downstream to the image forming unit 2 via the paper feed path 7. At the end of the paper feed path 7, a pair of registration rollers 8 is provided that aligns the leading edge of the sheets fed from each cassette 5 and waits for them to be fed according to the image formation timing of the image forming unit 2.

The image forming unit 2 can use various image forming mechanisms for forming images on sheets, such as an electrostatic printing mechanism, inkjet image forming method, offset printing method, or silk printing method. The image forming unit 2 shown in the figure is of a type that forms an image on a sheet using a known electrostatic printing mechanism.

A number of drums (four drums 9a-9d, corresponding to four color components in the illustrated embodiment) are arranged within the device housing 4. Each drum 9a, 9b, 9c, and 9d is comprised of a photoconductor and is equipped with a light emitter (such as a laser head) 10 and a developer 11. A latent image (electrostatic image) is formed on each drum 9a-9d by the light emitter 10, and toner ink is applied by the developer 11. The ink images applied to each drum are transferred to a transfer belt 12 for each color component and synthesized. The transferred image formed on the transfer belt 12 is transferred by a charger 13 onto a sheet fed from the paper feed unit 1, fixed by a fuser (heating roller) 14, and then sent to the paper discharge unit 3.

The paper discharge unit 3 has a paper discharge outlet 16 that conveys sheets to a paper discharge space (internal space) 15, and a paper discharge path 17 that guides sheets from the image forming unit 2 to the paper discharge outlet 16. Furthermore, a duplex path 18 is connected to the paper discharge unit 3 so that sheets with images formed on their front sides can be turned over and fed back to the image forming unit 2.

The duplex path 18 inverts sheets that have had an image formed on their front side by the image forming unit 2 and sends them back to the image forming unit 2. Sheets that have had an image formed on their back side by the image forming unit 2 are discharged from the paper discharge outlet 16. For this reason, the duplex path 18 is equipped with a switchback path that reverses the conveying direction of sheets sent from the image forming unit 2 and returns them, and a U-turn path 18a that inverts the returned sheets.

[Image reading unit]
The image reading unit C includes a platen 19a made of transparent glass and a reading carriage 19b that reciprocates along the platen 19a. The reading carriage 19b includes a light source lamp, an optical mirror that reflects light from the document, and a photoelectric conversion element. The photoelectric conversion element is made up of line sensors arranged in the document width direction (main scanning direction) on the platen.

The document image on the platen 19a is read by scanning the reading carriage 19b as it moves in the sub-scanning direction perpendicular to the main scanning direction. Furthermore, the reading carriage 19b can remain stationary while reading the document image traveling at a predetermined speed on the platen 19a.

[Automatic document feeder unit]
The automatic document feeder unit D is disposed above the image reading surface of the platen 19a and includes a feeder mechanism that feeds document sheets set on a paper feed tray one by one to the platen 19a, reads the images on the document sheets using the reading carriage 19b, and then stores the document sheets in an output tray. The feeder mechanism is configured to run the document sheets from the paper feed tray over the image reading surface of the platen 19a at a predetermined speed.

[Sheet processing device]
2, the sheet processing device B includes a device housing 21, a transport path 22 provided within the device housing for transporting sheets in the sheet transport direction, a processing tray 24 disposed downstream of a sheet discharge outlet 23 of the transport path, and a stacking tray 25 disposed further downstream thereof. The processing tray 24 is provided with a sheet carry-in mechanism 26 for carrying sheets discharged from the sheet discharge outlet 23 to the rear side of the processing tray 24, i.e., the upstream side in the sheet transport direction, a sheet alignment mechanism 27 for accumulating and positioning a plurality of sheets carried into the processing tray 24 in a bundle, and a binding mechanism 28 for binding the aligned sheet bundle.

The transport path 22 is equipped with a feeder mechanism in which pairs of transport rollers, such as a pair of transport rollers 31 and a pair of transport rollers 32, are arranged at a predetermined interval to transport the sheet received from the image forming unit B from the transport entrance 30 to the paper discharge exit 23. It is advantageous if the transport path 22 is equipped with a sheet sensor for detecting the leading and/or trailing edges of the sheet being transported.

As shown in the figure, the processing tray 24 is positioned at a predetermined step below the paper discharge outlet 23 of the transport path 22. The processing tray 24 has a paper support surface 24a for supporting at least a portion of the sheets discharged from the paper discharge outlet 23 so that the sheets can be stacked vertically and accumulated into a bundle, i.e., a sheet stack. A sheet edge regulating means 29, which constitutes a sheet alignment mechanism 27, is disposed at the upstream end of the processing tray 24 in the sheet transport direction.

In this embodiment, a so-called bridge support structure is employed in which the front (downstream) portion of the sheet along the sheet transport direction is supported by the stacking tray 25, and the opposite rear (upstream) portion is supported by the processing tray 24. As a result, sheet processing device B reduces the overall tray dimensions of the processing tray 24 in the sheet transport direction, i.e., in the direction in which sheets are transported into (or out of) the processing tray 24.

The sheet loading mechanism 26 is equipped with a transport roller device 47 to smoothly transport sheets discharged from the discharge outlet 23 via the step toward the back of the processing tray 24 in the correct orientation, i.e., with the left and right side edges of the sheet width aligned in the loading direction. The transport roller device 47 has a roller pair consisting of an upper transport roller 48 and a lower driven roller 49, sandwiching the processing tray 24 between them. The transport roller 48 is rotatably supported at the tip of a lift bracket 50 that is swingably supported above the processing tray 24, and the driven roller 49 is rotatably mounted in a fixed position immediately below the processing tray.

The sheet feed mechanism 26 further includes a pick-up rotor 33 for guiding the leading edge of the sheet toward the rear in the feed direction to accommodate curling or skew that may occur when the sheet is transported to the rear of the processing tray 24. The pick-up rotor 33 has a pick-up belt 34 made of a ring-shaped (or short cylindrical) belt member located above the processing tray 24 and in front of the sheet edge regulating means 29 in the feed direction.

The take-in belt 34 is movable up and down by a lifting mechanism (not shown) toward the top surface of the sheets on the paper loading surface 24a. The take-in belt 34 descends in time with the sheet being transported into the processing tray 24 by the transport roller device 47 in the transport direction, engages with the top surface of the uppermost sheet on the paper loading surface 24a, and rotates in a direction that transports the sheet in the transport direction.

The sheet alignment mechanism 27 is composed of the sheet edge regulating means 29 and side alignment means 40 described above. As shown in FIG. 3, the sheet edge regulating means 29 includes multiple (three in the illustrated embodiment) sheet edge regulating members 36-38 arranged along the sheet width direction on the edge of the processing tray 24 on the rear side in the carry-in direction (upstream side in the sheet transport direction). The main sheet edge regulating member 36 is fixedly installed at the center position in the sheet width direction, which serves as the center reference for the processing tray 24. A first sheet edge regulating member 37 is arranged on the rear side of the device (right side in the figure) of the main sheet edge regulating member 36 in the sheet width direction, and a second sheet edge regulating member 38 is arranged on the front side of the device (left side in the figure).

The first and second binding means 51 and 52 that constitute the binding mechanism 28 are disposed immediately outside the rear edge of the processing tray 24 in the feed direction. In this embodiment, the first binding means 51 is a staple binding device that performs staple binding, as described below, and the second binding means 52 is a stapleless binding device that performs stapleless binding. In FIG. 3, the first binding means 51 is disposed closer to the front of the device (left side in the figure) than the second sheet edge regulating member 38 in the sheet width direction, and is movable along the rear edge of the processing tray 24 in the feed direction (i.e., the sheet edge regulated by the sheet edge regulating means 29). The second binding means 52 is fixed near a corner of the processing tray 24, closer to the rear of the device (right side in the figure) than the first sheet edge regulating member 37 in the sheet width direction.

As shown in Figure 2 for the second sheet edge regulating member 38, the sheet edge regulating members 36-38 have sheet edge regulating portions 41-43 made of channel-shaped members with a U-shaped cross section. The main sheet edge regulating member 36 has a pair of sheet edge regulating portions 41 on either side of the center reference in the sheet width direction. The inside of the U-shaped sheet edge regulating portions 41-43 are provided with regulating surfaces 41a-43a that abut and stop the leading edge of a sheet in the carry-in direction (the upstream edge in the sheet transport direction) being transported on the processing tray 24. The regulating surfaces 41a-43a are positioned to align their positions in the sheet carry-in direction, thereby regulating and/or aligning the positions of the sheets and sheet stacks on the processing tray 24 in the sheet carry-in direction.

In Figure 3, the first sheet edge regulating member 37 and the second sheet edge regulating member 38 are arranged symmetrically in the sheet width direction, sandwiching the main sheet edge regulating member 36. While the second sheet edge regulating member 38 is fixed in the position shown, the first sheet edge regulating member 37 is movable between the position shown in Figure 3 as a first position (reference position) and a second position set toward the rear of the device (right side in the figure) in the sheet width direction. Note that the second sheet edge regulating member 38 can also be configured to be movable in the sheet width direction, if necessary.

Figure 4(a) shows the first sheet edge regulating member 37 in the first position, and Figure 4(b) shows the first sheet edge regulating member 37 in the second position. The first sheet edge regulating member 37 has its sheet edge regulating portion 42 attached integrally to the upper surface of a slide member 44, which is positioned at a height not exceeding the paper loading surface 24a. The slide member 44 is supported by a slide shaft 45 in the sheet width direction, which is fixed to the device housing 21, so that it can slide freely along the slide shaft. This allows the first sheet edge regulating member 37 to move integrally with the slide member 44 in the sheet width direction along the slide shaft 45.

The slide shaft 45 extends in the sheet width direction along the rear edge of the processing tray 24 in the feed direction, covering at least the range over which the first sheet edge regulating member 37 can move from the first position toward the rear of the device. A stopper 46 that abuts and engages the first sheet edge regulating member 37 or the slide member 44 is provided on the slide shaft 45 and/or the device housing 21 to prevent the first sheet edge regulating member 37 from moving beyond the first position toward the front of the device.

The slide member 44 is provided with a biasing means, which in this embodiment is a coil spring 53. One end 53a of the coil spring 53 is fixed to the slide member 44, and the other end 53b is fixed to the device housing 21, constantly biasing the slide member 44 from the rear side of the device toward the first position. Therefore, after the first sheet edge regulating member 37 moves toward the second position, it can automatically and easily return to the first position by the biasing force of the coil spring 53.

Furthermore, an engagement member 54 is integrally formed on the slide member 44 and engages with the first binding means 51, which moves from the front side of the device to the rear side of the device along the sheet width direction. As shown in FIG. 4, the engagement member 54 is formed of a rigid rod-shaped member that protrudes downstream in the feed direction from the slide member 44. As shown in FIG. 5, the engagement member 54 is positioned so that it can engage with an engagement portion 55 provided on the end of the first binding means 51 on the rear side of the device.

When the first binding means 51 moves toward the rear of the device in the sheet width direction, past the second sheet edge regulating member 38 and the main sheet edge regulating member 36, the engagement portion 55 abuts and presses against the engagement member 54, causing the slide member 44 and first sheet edge regulating member 37 to move toward the second position together with the first binding means 51 against the biasing force of the coil spring 53, and to stop when the first binding means 51 stops. When the first binding means 51 moves from its stopped position toward the front of the device, the slide member 44 and first sheet edge regulating member 37 correspondingly move toward the first position due to the biasing force of the coil spring 53. When the first binding means 51 moves further toward the front of the device beyond the first position, the slide member 44 and first sheet edge regulating member 37 are engaged by the stopper 46 and stopped at the first position.

The first sheet edge regulating member 37 further includes a guide portion 57 for sheets being fed into the processing tray 24. As shown in FIG. 6, the guide portion 57 has a guide surface 58 facing the sheet surface on the processing tray 24. The guide surface 58 has a flat portion 58a at the downstream end in the feed direction that is approximately parallel to the paper loading surface 24a, and an inclined surface portion 58b that curves outward from the flat portion 58a toward the upstream side in the feed direction.

The guide section 57 is attached to the upper end of the sheet edge restriction section 42 on the upstream side in the feed direction via a parallel link mechanism 59. As shown in Figures 5 and 6, the parallel link mechanism 59 is a symmetrical four-joint link structure in which two sets of parallel link arms 61a-61d and 62a-62d are rotatably connected by four common support shafts 63a-63d to form a parallelogram, with the guide section 57 attached integrally to the support shaft 63a on the upstream side in the feed direction.

The parallel link mechanism 59 is provided with a spring 64 that constantly biases the guide portion 57 toward the paper loading surface 24a. As a result, sheets carried onto the processing tray 24 are guided downstream in the carrying direction by the guide surface 58 and are pressed toward the paper loading surface 24a by the flat portion 58a. Even if the height of the sheets on the processing tray 24 increases, the parallel link mechanism 59 lifts the guide portion 57 against the biasing force of the spring 64, constantly pressing the sheets on the processing tray 24 toward the paper loading surface 24a and preventing the top sheet from floating above the sheets below.

The side alignment means 40 moves sheets and sheet stacks on the processing tray 24 in the sheet width direction, and regulates and/or aligns their widthwise position with their side edges. To this end, the side alignment means 40 has a pair of side alignment members 65, 66 arranged on either side of the center reference of the processing tray 24, as shown in FIG. 3. The side alignment members 65, 66 are flat plate-shaped members that extend vertically upward from the paper loading surface 24a of the processing tray 24 with their inner surfaces facing each other. The inner surfaces of each side alignment member 65, 66 engage with adjacent widthwise side edges of sheets on the processing tray 24, functioning as regulating surfaces 65a, 66a that regulate the widthwise position of the sheets.

Each side alignment member 65, 66 is integrally connected to a movable support portion (not shown) located on the rear side of the processing tray 24 via linear slits 67, 68 extending through the processing tray in the sheet width direction. For example, by individually rotating pinions that mesh with racks formed on each movable support portion using a drive motor, the side alignment members 65, 66 can be moved independently toward or away from each other and stopped at the desired width direction position. This allows the sheet width direction position of each side alignment member 65, 66 to be individually set according to the size of the sheets being transported to the processing tray 24, and the position, movement amount, and offset amount from the center reference can be determined when moving a stack of sheets in the sheet width direction.

[First binding means]
As described above, the first binding means 51 is a known stapling unit that uses metal staples to staple multiple locations on the edge of a sheet. As shown in Fig. 2, the first binding means 51 has an opening 71 that opens upstream in the feed direction toward the processing tray 24 in order to staple the downstream edge of the sheet on the processing tray 24 in the feed direction. The downstream edge of the sheet on the processing tray 24 in the feed direction protrudes from the paper mounting surface 24a downstream in the feed direction and enters the opening 71, where it is stapled.

The opening 71 penetrates the staple unit in the sheet width direction, and its dimensions are slightly larger than the sheet edge regulating portions 41-43 of the sheet edge regulating members 36-38 when viewed in the sheet width direction, and it is positioned at a height that includes the sheet edge regulating portions 41-43 inside it. Therefore, when the first binding means 51 is moved in the sheet width direction, it can smoothly pass through the second sheet edge regulating member 38 and the main sheet edge regulating member 37.

In contrast, because the first sheet edge regulating member 37 is provided with the aforementioned engagement member 54, the first binding means 51 cannot move over the first sheet edge regulating member 37 toward the rear of the device. In other words, the first sheet edge regulating member 37 is arranged to be movable in the sheet width direction while located between the first binding means 51 and the second binding means 52.

In a broad sense, the first binding means 51 includes a housing having an opening 71, a staple binding processing unit held in the housing that performs the staple processing on the sheet stack, a drive motor that drives the staple binding processing unit to perform the staple processing, and a slide rail and drive motor that move the housing in the sheet width direction. However, in the following description, the first binding means 51 refers to a device configuration in the narrow sense that includes the staple binding processing unit and the housing and moves in the sheet width direction.

[Second binding means]
The second binding means 52 is a crimp binding device that performs stapleless binding using a press bind mechanism that crimps and deforms the sheet stack between a pair of upper and lower crimping teeth having uneven surfaces, for example. As shown in Figure 3, the second binding means 52 includes a crimp binding unit 72 with upper and lower crimping teeth at a position downstream in the sheet feed direction on the processing tray 24 and corresponding to a corner portion on the rear side of the device in the sheet width direction. The crimp binding unit 72 has an opening (not shown) for guiding the corner portion of the sheet on the processing tray 24 between the upper and lower crimping teeth.

[Sheet Conveying Operation of Sheet Processing Apparatus]
2, 7, and 8, the transport operation of a sheet and a sheet stack in the sheet processing device B will be described. The sheet S transported from the image forming unit A to the sheet processing device B is sent in the sheet transport direction from the carry-in entrance 30 along the transport path 22 by the transport roller pair, and is discharged from the paper discharge outlet 23 onto the processing tray 24, as shown in Fig. 2. At this time, the transport roller 48 is held in a standby position above the processing tray 24 by the lift bracket 50 so as not to interfere with the discharge of the sheet.

As shown in Figure 7(a), when the rear end of sheet S1 is discharged from the paper discharge port 23 and reaches the processing tray 24, as shown in Figure 7(b), the lifting bracket 50 rotates downward, causing the upper transport roller 48 to abut against the top surface of the sheet on the processing tray 24. At this point, the next sheet S2 is transported from image forming unit A and waits in the transport path 22.

Next, the conveying roller 48 is belt-driven, for example, by a drive motor (not shown), to rotate counterclockwise in the figure. As a result, sheet S1 is conveyed on the processing tray 24 in the carry-in direction, i.e., in the opposite direction to the stacking tray 25. The pick-up rotor 33 is then rotated, and the sheet S1 is conveyed until its leading edge in the carry-in direction (the right edge in the figure) hits the regulating surface of the sheet end regulating means 29.

Similarly, as shown in FIG. 7(c), immediately after the lifting bracket 50 rotates and the transport roller 48 retreats to the upper standby position, the next sheet S2 is transported through the transport path 22 and discharged from the discharge outlet 23 onto the previous sheet S1 on the processing tray 24. As shown in FIG. 8(a), as in FIG. 7(b), the downward rotation of the lifting bracket 50 causes the transport roller 48 to rotate in contact with the upper surface of the sheet on the processing tray 24, and the pick-up rotor 33 is further rotated, transporting the sheet S2 until its leading edge in the feed direction hits the regulating surface of the sheet end regulating means 29.

In this way, a predetermined number of sheets S are accumulated on the processing tray 24, and once they have been aligned in the sheet width direction and the feed direction by the sheet alignment mechanism 27, the binding process is performed using the first binding means 51 or the second binding means 52. As shown in Figure 8(b), the bound sheet stack Sb is transported in the sheet transport direction on the processing tray 24 by rotating the transport roller 48 and the pick-up rotor 33 that are in contact with the upper surface in the opposite direction, and the stack is discharged onto the stack tray 25 as shown in Figure 8(c).

[Binding operation]
The following describes the sheet binding operation performed by the sheet processing device B. In the following Examples 1 to 4, the sheet width dimension of the sheets to be bound is divided into cases where it is greater than a predetermined value and cases where it is equal to or less than the predetermined value. In each example, the sheets are bound near the corners on the rear side of the device and on the leading edge side in the feed direction.

[Example 1]
In Example 1, A4 size sheets are placed landscape with their long sides aligned in the sheet width direction, and the sheet width dimension is greater than a predetermined value, and staple binding is performed on the corners of the sheets using the first binding means 51. The following description will be given with reference to Figures 9 to 12.

Figure 9(a) shows the initial position of Figure 3, in which the first sheet edge regulating member 37 is in the first position and the side alignment members 65, 66 are positioned at the outermost positions in the sheet width direction. From this initial position, as shown in Figure 9(b), the first binding means 51 is moved in the sheet width direction toward the rear of the device until the first sheet edge regulating member 37 is positioned integrally with the first binding means 51 at the second position. Thereafter, as shown in Figure 10(a), the first sheet S1 is discharged onto the processing tray 24.

As shown in Figure 10(b), the sheet carry-in mechanism 26 is operated to bring the leading edge Se of the sheet S in the carry-in direction into contact with the regulating surfaces 41a-43a of each sheet edge regulating section 41-43, and the side alignment members 65, 66 are moved to regulate both side edges Ss of the sheet S in the sheet width direction, thereby aligning the position of the sheet S in the carry-in direction and the sheet width direction. Next, the side alignment members 65, 66 are returned to their original outermost positions in the sheet width direction, and then the second sheet S2 is discharged onto the preceding sheet S1 on the processing tray 24, as shown in Figure 11(a).

The sheet feed mechanism 26 and side alignment members 65, 66 are operated in the same manner as described above in connection with Figure 10(b) to align sheet S2, together with the sheets stacked below it, in the feed direction and sheet width direction, as shown in Figure 11(b). After a predetermined number of sheets have been aligned on the processing tray 24 in this manner, the side alignment members 65, 66 are moved a predetermined distance in the sheet width direction toward the front of the device, as shown in Figure 12(a), to shift the sheet stack Sb to a position where its corner portion is aligned with the binding position of the first binding means 51.

In this state, the first binding device 51 performs the binding process, stapling the sheet stack Sb at the corners as shown in FIG. 12(b). The bound sheet stack Sb is then ejected from the processing tray 24 onto the stacking tray 25 as described above in connection with FIG. 8.

[Example 2]
In Example 2, A4 size sheets are oriented vertically with their short sides aligned in the sheet width direction, and the sheet width dimension is equal to or less than a predetermined value, and staple binding is performed on the corners of the sheets using the first binding means 51. The following description will be given with reference to Figures 13 to 16.

Figure 13(a) similarly shows the initial position of Figure 3, in which the first sheet edge regulating member 37 is in the first position and the side alignment members 65, 66 are positioned at the outermost positions in the sheet width direction. With this initial position intact, the first sheet S1 is discharged onto the processing tray 24, as shown in Figure 13(b). At this time, it is advantageous to move the side alignment members 65, 66 inward from their outermost positions in advance.

Next, as shown in FIG. 14(a), the sheet carry-in mechanism 26 is operated to bring the leading edge Se of the sheet S in the carry-in direction into contact with the regulating surfaces 41a-43a of each sheet edge regulating portion 41-43, and the side alignment members 65, 66 are moved to regulate both side edges Ss of the sheet S in the sheet width direction, thereby aligning the position of the sheet S in the carry-in direction and the sheet width direction. After the side alignment members 65, 66 are returned to the positions shown in FIG. 13(b), the second sheet S2 is discharged onto the preceding sheet S1 on the processing tray 24, as shown in FIG. 14(b).

As described above in connection with FIG. 14(a), the sheet feed mechanism 26 and side alignment members 65, 66 are operated to align sheet S2, together with the sheets stacked below it, in the feed direction and the sheet width direction, as shown in FIG. 15(a). After a predetermined number of sheets have been aligned on the processing tray 24 in this manner, the first binding means 51 is moved in the sheet width direction toward the rear of the device until the first sheet edge regulating member 37 is positioned integrally with the first binding means 51 at the second position, as shown in FIG. 15(b).

This aligns the binding position of the first binding device 51 with the corner of the sheet bundle Sb. In this state, the binding process is performed by the first binding device 51, and the sheet bundle Sb is stapled at the corner, as shown in FIG. 16. The bound sheet bundle Sb is then ejected from the processing tray 24 onto the stacking tray 25, as described above in connection with FIG. 8.

In the above-described embodiment, when the first binding device 51 is used to staple the corner portion of the sheet S on the rear side of the device, the first binding device 51 does not move further toward the rear side of the device (i.e., toward the second binding device 52) by climbing over the first sheet end regulating member 37 that has moved to the second position. Therefore, the first binding device 51 does not interfere with the second binding device 52.

In a similar conventional structure, the first binding means moves toward the second binding means, climbing over the sheet edge regulating member at the rear of the device (located at the position of the first sheet edge regulating member 37 in this embodiment) to staple the corners of the sheets S. As a result, the second binding means had to be retracted each time to avoid interference, or positioned offset in the feed direction.

In the configuration of this embodiment, there is no risk of interference with the first binding means 51, so the second binding means 52 can be fixedly positioned in the same line as the sheet movement direction in the sheet width direction. Therefore, there is no need for a retreat space for the second binding means 52 or a mechanism to offset the sheet stack in the feed direction toward the stapleless binding processing position by the second binding means 52, allowing the entire sheet processing device B to be configured compactly.

Comparing the above-described first and second embodiments, the movement timing of the first binding means 51 and the first sheet edge regulating member 37 is set to differ depending on the sheet width size. This is because, in the second embodiment, in which the first binding means 51 binds sheets with a small width size, if the first sheet edge regulating member 37 were to move to the second position before moving the sheet S on the processing tray 24 in the carry-in direction, as in the first embodiment, the first sheet edge regulating member 37 would be positioned further toward the rear of the device than the sheet edge Ss on the side alignment member 65 side of the sheet S, resulting in the inability to regulate the sheet edge Se. Therefore, it is preferable that the first sheet edge regulating member 37 be positioned so that the sheet edge Se can abut against the regulating surface 42a of the sheet edge regulating portion 42 when the sheet S discharged onto the processing tray 24 is moved in the carry-in direction.

The first sheet edge regulating member 37 can be set at multiple "second positions" in the sheet width direction. In this case, all positions toward the rear of the device from the first position, which is closest to the front of the device, are considered to be second positions. For example, when a sheet S discharged onto the processing tray 24 is moved in the feed direction, the first sheet edge regulating member 37 can be positioned in small increments to match the sheet size in the sheet width direction so that it is always a predetermined distance, for example, 10 mm, toward the front of the device from the position of the sheet edge Ss regulated by the side regulating member 65. This allows the first sheet edge regulating member 37 to be positioned so that the sheet edge Se can always abut against the regulating surface 42a, even for sheets whose sheet width direction size is between the A4 landscape orientation in Example 1 and the A4 portrait orientation in Example 2.

[Example 3]
In Example 3, similar to Example 1, A4 size sheets are placed landscape with their long sides aligned in the sheet width direction, and the sheet width dimension is greater than a predetermined value, and stapleless binding is performed on the corners of the sheets using the second binding means 52. The following description will be given with reference to Figures 17 to 20.

Figure 17(a) similarly shows the initial position of Figure 3, in which the first sheet edge regulating member 37 is in the first position and the side alignment members 65, 66 are positioned at the outermost positions in the sheet width direction. From this initial position, as shown in Figure 17(b), the first binding means 51 is moved in the sheet width direction toward the rear of the device until the first sheet edge regulating member 37 is positioned integrally with the first binding means 51 at the second position. Thereafter, as shown in Figure 18(a), the first sheet S1 is discharged onto the processing tray 24. At this time, it is convenient to move the side alignment members 65, 66 inward from their outermost positions in advance.

As shown in Figure 18(b), the sheet carry-in mechanism 26 is operated to bring the leading edge Se of the sheet S in the carry-in direction into contact with the regulating surfaces 41a-43a of each sheet edge regulating portion 41-43, and the side alignment members 65, 66 are moved to regulate both side edges Ss of the sheet S in the sheet width direction, thereby aligning the position of the sheet S in the carry-in direction and the sheet width direction. Next, the side alignment members 65, 66 are returned to the positions shown in Figure 18(a), and then the second sheet S2 is discharged onto the preceding sheet S1 in the processing tray 24, as shown in Figure 19(a).

The sheet feed mechanism 26 and side alignment members 65, 66 are operated in the same manner as described above in connection with Figure 18(b) to align sheet S2, together with the sheets stacked below it, in the feed direction and sheet width direction, as shown in Figure 19(b). After a predetermined number of sheets have been aligned on the processing tray 24 in this manner, as shown in Figure 20(a), the side alignment members 65, 66 are moved in the sheet width direction toward the rear of the device until the side alignment member 65 closest to the second binding means 52 reaches its outermost position, and the sheet stack Sb is shifted to a position where its corner is aligned with the binding position of the second binding means 52.

In this state, the second binding device 52 performs the binding process, and stapleless binding is performed on the sheet stack Sb by crimping the corners, as shown in Figure 20(b). The bound sheet stack Sb is then ejected from the processing tray 24 onto the stacking tray 25, as described above in connection with Figure 8.

[Example 4]
In Example 4, B5 size sheets are placed horizontally with their long sides aligned in the sheet width direction, and the sheet width dimension is equal to or less than a predetermined value, and stapleless binding is performed on the corners of the sheets using the second binding means 52. This will be described below with reference to Figures 21 to 25.

Figure 21(a) similarly shows the initial position of Figure 3, in which the first sheet edge regulating member 37 is in the first position and the side alignment members 65, 66 are positioned at the outermost positions in the sheet width direction. With this initial position intact, the first sheet S1 is discharged onto the processing tray 24, as shown in Figure 21(b). At this time, it is advantageous to move the side alignment members 65, 66 inward from their outermost positions in advance.

Next, as shown in Figure 22(a), the sheet carry-in mechanism 26 is operated to bring the leading edge Se of the sheet S in the carry-in direction into contact with the regulating surfaces 41a-43a of each sheet edge regulating portion 41-43, and the side alignment members 65, 66 are moved to regulate both side edges Ss of the sheet S in the sheet width direction, thereby aligning the position of the sheet S in the carry-in direction and the sheet width direction. After the side alignment members 65, 66 are returned to the positions shown in Figure 21(b), the second sheet S2 is discharged onto the preceding sheet S1 on the processing tray 24, as shown in Figure 22(b).

As described above in connection with FIG. 22(a), the sheet feed mechanism 26 and side alignment members 65, 66 are operated to align sheet S2, together with the sheets stacked below it, in the feed direction and sheet width direction, as shown in FIG. 23(a). After a predetermined number of sheets have been aligned on the processing tray 24 in this manner, the side alignment members 65, 66 are shifted a predetermined amount in the sheet width direction toward the rear of the device, shifting the sheet stack Sb until its corner portion is positioned just before the binding position of the second binding means 52, as shown in FIG. 23(b).

Next, the first binding means 51 is moved toward the rear of the device in the sheet width direction until the first sheet edge regulating member 37 is positioned integrally with the first binding means 51 at the second position, as shown in FIG. 24(a). Furthermore, the side alignment members 65, 66 are moved toward the rear of the device in the sheet width direction until the side alignment member 65 closest to the second binding means 52 reaches its outermost position, and the sheet stack Sb is shifted to a position where its corner is aligned with the binding position of the second binding means 52, as shown in FIG. 24(b).

The shifting of the sheet stack Sb described above in connection with FIG. 23(a) and the movement of the first sheet edge regulating member 37 to the second position described above in connection with FIG. 24(a) can be performed simultaneously. At this time, the condition is that the edge Se of the shifting sheet stack Sb maintains contact with the regulating surface 42a of the moving first sheet edge regulating member 37 without moving away from or disengaging from it. For example, if the shifting of the sheet stack Sb is performed at the same speed as or faster than the movement of the first sheet edge regulating member 37 to the second position, it is easier to maintain contact between the sheet stack edge Se and the regulating surface 42a, which is advantageous.

By shifting the sheet stack Sb as shown in Figure 24(b), the corner portion of the sheet stack Sb is lifted from the paper loading surface 24a by a guide portion 24b, which is slightly raised from the paper loading surface 24a, at the corner portion of the processing tray 24 at the rear of the device in the sheet width direction and at the leading edge in the feed direction, as shown in Figure 25(a). This allows the corner portion of the sheet stack Sb to be smoothly guided into the opening of the pressure binding portion 72 of the second binding means 52.

The sheet bundle Sb can also be shifted so that the corner portion thereof is guided into the opening of the second binding means 52 while the first sheet end regulating member 37 is moving to the second position in Figure 24(a). However, since the sheet bundle Sb is pressed onto the paper mounting surface 24a by the guide portion 57 of the first sheet end regulating member 37, it is preferable that the first sheet end regulating member 37 is positioned closer to the second binding means 52, as this makes it easier to guide the corner portion of the sheet bundle Sb into the opening of the second binding means 52. Therefore, in the embodiment,
After the first sheet end regulating member 37 has completed its movement to the position closest to the second binding means 52 , the sheet stack Sb is shifted to guide the corner portion to the opening of the second binding means 52 .

In this state, the second binding device 52 performs the binding process, and stapleless binding is performed on the sheet stack Sb by crimping the corners, as shown in Figure 25(b). The bound sheet stack Sb is then ejected from the processing tray 24 onto the stacking tray 25, as described above in connection with Figure 8.

The positional relationship between the sheet edge Se and the first sheet edge regulating member 37 when the sheet S discharged onto the processing tray 24 is moved in the carry-in direction, as described above in relation to Examples 1 and 2, is preferably set in the same way in the stapleless binding process using the second binding means 52 in Examples 3 and 4. This allows the first sheet edge regulating member 37 to be positioned so that the sheet edge Se can always abut against the regulating surface 42a, in accordance with the sheet size in the sheet width direction of the sheet S discharged onto the processing tray 24.

In the above embodiment, the sheet transport direction in which the sheet S is discharged from the discharge port 23 to the processing tray 24 and the carry-in direction in which the sheet S discharged onto the processing tray 24 is carried toward the sheet edge regulating means 29 are configured to be opposite directions, i.e., switchback transport, when the sheet processing device B is viewed in a plan view as shown in Figure 3. In another embodiment, the sheet transport direction and the carry-in direction can also be configured to intersect (e.g., perpendicular to) each other when viewed in a plan view. In this case, the "sheet edge Se" in the sheet width direction described above is the sheet edge in a direction intersecting (perpendicular to) the carry-in direction. In either case, the direction along the sheet edge Se regulated by the sheet edge regulating means 29 (sheet edge regulating members 36-38) remains the sheet width direction.

In the above embodiment, the first sheet edge regulating member 37 moves between the first position and the second position using the movement of the first binding device 51 in the sheet width direction and the biasing force of the coil spring 53 as drive sources. In another embodiment, the first sheet edge regulating member 37 can be moved using a different drive source. For example, the first sheet edge regulating member 37 can be moved using a dedicated drive motor or solenoid. Alternatively, the first sheet edge regulating member 37 can be moved using a drive motor for another component, such as the side alignment members 65, 66 or the first binding device 51, as a drive source.

The present invention has been described above in relation to preferred embodiments, but it goes without saying that the present invention is not limited to the above embodiments and can be implemented with various modifications and variations within its technical scope.

A Image forming unit B Sheet processing device C Image reading unit D Document feeding unit 24 Processing tray 24a Paper loading surface 25 Stacking tray 26 Sheet carrying mechanism 27 Sheet alignment mechanism 29 Sheet edge regulating means 37 First sheet edge regulating member 38 Second sheet edge regulating member 51 First binding means 52 Second binding means 65, 66 Side alignment means

Claims (4)

A sheet processing apparatus that performs binding processing on a sheet bundle,
a tray for stacking the conveyed sheets one by one to form a sheet bundle;
a plurality of abutting means arranged in front and rear directions of the sheet processing apparatus, against which the edge of the sheet on the tray abuts;
a shift unit that shifts the sheet that has been abutted against the abutting means in the front-to-rear direction;
a stapler configured to be able to staple a corner portion of the sheet stack abutted against the abutting means and on the rear side in the front-rear direction of the sheet stack;
a stapleless binding unit that is provided on the rear side of the abutting means and is configured to be able to perform stapleless binding on a corner portion of the sheet bundle that is abutted against the abutting means and that is on the rear side of the sheet bundle;
Equipped with
The abutting means is configured such that an abutting member disposed at the innermost side in the front-rear direction is movable in the front-rear direction on the front side of the stapleless binding unit in the front-rear direction,
When the stapler performs the staple processing on the corner portion of a sheet stack consisting of specified sheets, the sheet processing device is characterized in that the staple processing is performed on the corner portion of the sheet stack closer to the front than the abutment member that has moved to the rear by moving the abutment member toward the rear and shifting the sheets toward the front by the shift unit . 2. The sheet processing apparatus according to claim 1, wherein the staple-free binding unit is fixedly positioned further back than the abutment member, and is configured to be able to perform the staple-free binding process on the corner portion of the sheet stack by shifting the sheet that has abutted against the abutment member to the back side using the shift unit . 2. The sheet processing apparatus according to claim 1, wherein the abutment member moves to the rear side as the stapler moves from the front side to the rear side in the front-to-rear direction, and moves to the front side as the stapler moves from the rear side to the front side . an image forming unit that forms an image on a sheet ;
an image reading unit disposed above the image forming unit;
an internal space defined between the image forming unit and the image reading unit;
a sheet processing unit that is mounted in the internal space of the body and that performs a binding process on a sheet stack made up of sheets on which images have been formed by the image forming unit ,
4. An image forming apparatus, wherein the sheet processing unit is a sheet processing apparatus according to claim 1.