SHEET PROCESSING APPARATUS AND IMAGE FORMING SYSTEM

BACKGROUND OF THE INVENTION
Field of the Invention

The present invention relates to a sheet processing apparatus including a binding processing portion that performs binding processing on sheets, and an image forming system including the sheet processing apparatus.

Description of the Related Art

Hitherto, as a sheet processing apparatus including a processing unit including a processing portion that performs binding processing on sheets and a sending portion that sends the sheets bound by the processing portion, and a stacking tray (stacking portion) on which the sheets sent from the sending portion of the processing unit are stacked, a configuration for detecting the presence or absence of the sheet on the stacking tray that can move up and down with respect to the processing unit has been proposed (JP 2022-030667 A). In the configuration for detecting the presence or absence of the sheet as described in JP 2022-030667 A, a flag (displacement portion) that protrudes upward from an upper surface of the stacking portion and moves when the sheet is placed on the stacking tray, and a sensor (including an output portion that outputs an electric signal) shielded by the flag are disposed on the stacking tray that moves up and down. Such a flag and sensor are generally provided for the purpose of preventing products (sheets) of different jobs from being mixed on the stacking tray by detecting whether or not there is a sheet on the stacking tray.

Here, the sensor disposed on the stacking tray is electrically connected by a wiring to a circuit board (a determination portion that determines the presence or absence of the sheet on the stacking tray or a reception portion that receives an electric signal) disposed in the processing unit. Therefore, it is necessary to provide the wiring between the stacking tray outside the processing unit and the circuit board inside the processing unit. Then, since the stacking tray moves up and down with respect to the processing unit, the wiring also moves accordingly. In such a configuration according to the related art, it is necessary to take an advanced disconnection prevention measure to prevent disconnection of the wiring, and thus, complication of the configuration cannot be avoided.

SUMMARY OF THE INVENTION

The present invention provides a sheet processing apparatus and an image forming system that suppress disconnection of a wiring connecting a sensor for detecting the presence or absence of a sheet on a stacking tray that can move up and down and a circuit board while avoiding complication of a configuration.

According to a first aspect of the present invention, an image forming system includes an image forming unit including an image forming portion configured to form an image on a sheet, a processing unit including a processing portion configured to perform predetermined processing on the sheet on which the image is formed by the image forming portion, and a sending portion configured to send the sheet processed by the processing portion, a stacking portion configured to stack the sheet sent by the sending portion, a lifting/lowering portion provided in the processing unit and configured to lower the stacking portion such that a height of an uppermost sheet among the sheets sent by the sending portion and stacked on the stacking portion falls within a predetermined range and to lift the stacking portion in a case where the sheets stacked on the stacking portion are removed, a displacement portion provided on the stacking portion and configured to be displaced according to a presence or absence of the sheet on the stacking portion, an output portion provided in the processing unit and configured to output an electric signal according to the displacement of the displacement portion, a reception portion provided in the processing unit and configured to receive the electric signal output from the output portion, a wiring portion provided in the processing unit and configured to connect the output portion and the reception portion, and, a determination portion configured to determine the presence or absence of the sheet on the stacking portion according to the electric signal received by the reception portion.

According to a second aspect of the present invention, a sheet processing apparatus includes a processing unit including a processing portion configured to perform predetermined processing on a sheet and a sending portion configured to send the sheet processed by the processing portion, a stacking portion configured to stack the sheet sent by the sending portion, a lifting/lowering portion provided in the processing unit and configured to lower the stacking portion such that a height of an uppermost sheet among the sheets sent by the sending portion and stacked on the stacking portion falls within a predetermined range and to lift the stacking portion in a case where the sheets stacked on the stacking portion are removed, a displacement portion provided on the stacking portion and configured to be displaced according to a presence or absence of the sheet on the stacking portion, an output portion provided in the processing unit and configured to output an electric signal according to the displacement of the displacement portion, a determination portion provided in the processing unit and configured to determine the presence or absence of the sheet on the stacking portion according to the electric signal output from the output portion, and, a wiring portion provided in the processing unit and configured to connect the output portion and the determination portion.

According to a third aspect of the present invention, a sheet processing apparatus includes a processing unit including a processing portion configured to perform predetermined processing on a sheet received from an image forming unit including an image forming portion configured to form an image on the sheet, and a sending portion configured to send the sheet processed by the processing portion, a stacking portion configured to stack the sheet sent by the sending portion, a lifting/lowering portion provided in the processing unit and configured to lower the stacking portion such that a height of an uppermost sheet among the sheets sent by the sending portion and stacked on the stacking portion falls within a predetermined range and to lift the stacking portion in a case where the sheets stacked on the stacking portion are removed, a displacement portion provided on the stacking portion and configured to be displaced according to a presence or absence of the sheet on the stacking portion, an output portion provided in the processing unit and configured to output an electric signal according to the displacement of the displacement portion, a reception portion provided in the processing unit and configured to receive the electric signal output from the output portion, a wiring portion provided in the processing unit and configured to connect the output portion and the reception portion, and, a transmission portion provided in the processing unit and configured to transmit the electric signal received by the reception portion to the image forming unit including a determination portion configured to determine the presence or absence of the sheet on the stacking portion.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming system according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a sheet processing apparatus according to the first embodiment.

FIG. 3 is a control block diagram of the image forming system according to the first embodiment.

FIG. 4 is an enlarged cross-sectional view of a part of the sheet processing apparatus according to the first embodiment.

FIG. 5 is a perspective view of the periphery of a first tray according to the first embodiment.

FIG. 6 is a perspective view illustrating a configuration of a lifting/lowering mechanism of the first tray according to the first embodiment.

FIG. 7 is an enlarged perspective view illustrating a part of the lifting/lowering mechanism of the first tray according to the first embodiment.

FIG. 8 is a perspective view of a part of the lifting/lowering mechanism of the first tray according to the first embodiment when viewed from an opposite side to FIG. 7.

FIG. 9 is a perspective view illustrating a configuration related to detection of a sheet on the first tray according to the first embodiment.

FIG. 10 is a plan view illustrating a configuration related to detection of a sheet on the first tray according to the first embodiment.

FIG. 11 is a cross-sectional view of an upstream end portion side of the first tray illustrating a relationship between a flag according to the first embodiment and a light receiving portion of a processing unit side, and is a view of the apparatus when viewed from the back to the front.

FIG. 12 is a cross-sectional view of the upstream end portion side of the first tray illustrating the relationship between the flag according to the first embodiment and the light receiving portion of the processing unit side in a state in which there is a sheet on the first tray, and is a view of the apparatus when viewed from the back to the front.

FIG. 13 is a perspective view illustrating a configuration related to detection of a height position of the first tray according to the first embodiment.

FIG. 14 is a perspective view illustrating a configuration related to detection of a home position of the first tray according to the first embodiment.

FIG. 15 is a schematic diagram for describing a relationship between a shielding plate for detecting the height position of the first tray according to the first embodiment and each sensor.

FIG. 16 is a perspective view of the periphery of the flag for detecting the presence or absence of a sheet on the first tray according to the first embodiment.

FIG. 17 is a perspective view illustrating the flag for detecting the presence or absence of a sheet on the first tray according to the first embodiment.

FIG. 18 is a flowchart of sheet sending control according to the first embodiment.

FIG. 19 is a flowchart of a sheet presence/absence detection operation according to the first embodiment.

FIG. 20 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray is lifted to an upper surface detection position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 21 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray is lifted by a first predetermined distance from the upper surface detection position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 22 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray is lifted to a first predetermined position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 23 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray on which one sheet is stacked is lifted to the upper surface detection position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 24 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray on which one sheet is stacked is lifted by the first predetermined distance from the upper surface detection position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 25 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray on which one sheet is stacked is lifted to the first predetermined position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 26 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray on which about 10 sheets are stacked is lifted to the upper surface detection position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 27 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which the first tray on which 10 or more sheets are stacked is lifted by the first predetermined distance from the upper surface detection position in the sheet presence/absence detection operation according to the first embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 28 is a cross-sectional view of an upstream end portion side of a first tray illustrating a state in which there is a sheet on the first tray in a sheet presence/absence detection operation according to a second embodiment, and is a view of an apparatus when viewed from the front to the back.

FIG. 29 is a cross-sectional view of the upstream end portion side of the first tray illustrating a state in which there is no sheet on the first tray in the sheet presence/absence detection operation according to the second embodiment, and is a view of the apparatus when viewed from the front to the back.

FIG. 30 is a perspective view of a sheet presence/absence detection mechanism according to a third embodiment when viewed from below a first tray.

FIG. 31 is a cross-sectional view of an upstream end portion side of the first tray illustrating a relationship between a flag and a detection portion of a processing unit side according to the third embodiment in a state in which there is no sheet on the first tray, and is a view of an apparatus when viewed from the back to the front.

FIG. 32 is a cross-sectional view of the upstream end portion side of the first tray illustrating a relationship between the flag and the detection portion of the processing unit side according to the third embodiment in a state in which there is a sheet on the first tray, and is a view of the apparatus when viewed from the back to the front.

FIG. 33 is a cross-sectional view of an upstream end portion side of a first tray illustrating a relationship between a flag and a detection portion of a processing unit side according to a fourth embodiment in a state in which there is no sheet on the first tray, and is a view of an apparatus when viewed from the front to the back.

FIG. 34 is a cross-sectional view of the upstream end portion side of the first tray illustrating a relationship between the flag and the detection portion of the processing unit side according to the fourth embodiment in a state in which there is a sheet on the first tray, and is a view of the apparatus when viewed from the front to the back.

FIG. 35A is a perspective view schematically illustrating a relationship between a flag and a detection portion of a processing unit side according to a fifth embodiment in a state in which there is no sheet on a first tray.

FIG. 35B is a plan view schematically illustrating the relationship between the flag and the detection portion of the processing unit side according to the fifth embodiment in a state in which there is no sheet on the first tray.

FIG. 36A is a perspective view schematically illustrating a relationship between the flag and the detection portion of the processing unit side according to the fifth embodiment in a state in which there is a sheet on the first tray.

FIG. 36B is a plan view schematically illustrating a relationship between the flag and the detection portion of the processing unit side according to the fifth embodiment in a state in which there is a sheet on the first tray.

FIG. 37 is a cross-sectional view illustrating a schematic configuration of an image forming system including a sheet processing apparatus according to a first example of another embodiment.

FIG. 38 is a cross-sectional view illustrating a schematic configuration of an image forming system including a sheet processing apparatus according to a second example of another embodiment.

FIG. 39 is a cross-sectional view of the upstream end portion side of the first tray illustrating a relationship between the flag according to the first embodiment and the light receiving portion of the processing unit side in a state in which there is a sheet on the first tray at a timing other than during a job, and is a view of the apparatus when viewed from the back to the front.

DESCRIPTION OF THE EMBODIMENTS
First Embodiment

A first embodiment will be described with reference to FIGS. 1 to 27 and 39. First, a schematic configuration of an image forming system according to the present embodiment will be described with reference to FIG. 1.

Image Forming System

In the present embodiment, a copying machine is used as an image forming apparatus, and a sheet processing apparatus is connected to an opening portion of the copying machine for a sheet. An image forming system 1000 includes an image forming apparatus A and a sheet processing apparatus B, and the sheet processing apparatus B positioned downstream of the image forming apparatus A receives a sheet S subjected to an image formation by the image forming apparatus A, performs predetermined processing such as binding processing as necessary, and sends the sheet S to a sending portion positioned downstream of the sheet processing apparatus B. The image forming apparatus A includes various structures such as a copying machine, a printer, a printing machine, a facsimile machine, and a multifunction peripheral having a plurality of functions thereof. Hereinafter, the image forming apparatus A and the sheet processing apparatus B will be described in detail. In the following description, regarding the image forming apparatus A and the sheet processing apparatus B, a side on which an operator such as a user operates the apparatus (for example, a side on which an operation panel, an operation button, or the like is positioned) is referred to as a front side (a front side of paper surface of FIGS. 1 and 2 and the like), and a side opposite to the front side is referred to as a back side (a back side of paper surface of FIGS. 1 and 2 and the like).

Image Forming Apparatus

As illustrated in FIG. 1, the image forming apparatus A includes an image forming unit A1, an image reading unit A2, and a document feeding unit A3. The image forming unit A1 includes a feeding portion 2, an image forming portion 3, a sending portion 4, and a data processing portion 5 in an apparatus housing 1.

The feeding portion 2 includes a plurality of cassettes 2a, 2b, and 2c, and the sheets S of different standard sizes selected in advance can be stored in the cassettes 2a, 2b, and 2c, respectively. The sheet S is, for example, a paper sheet or a plastic sheet. Each of the cassettes 2a, 2b, and 2c incorporates a separation mechanism for separating the sheets S in the cassettes 2a, 2b, and 2c one by one and a feeding mechanism for feeding the sheets S. The sheet S having a size designated by a control portion 310 (FIG. 3) of the image forming apparatus A and stored in the feeding portion 2 having such a configuration is fed to a feeding path 6. The feeding path 6 is provided with a conveyance roller 7 that conveys the sheets S supplied from the plurality of cassettes 2a, 2b, and 2c downstream, and a registration roller pair 8 that is disposed at an end portion of the path and aligns leading edges of the sheets S, and the sheets S whose leading edges are aligned by the registration roller pair 8 are fed to the image forming portion 3 positioned downstream at a predetermined timing.

A large-capacity cassette 2d and a manual feed tray 2e are connected to the feeding path 6. The large-capacity cassette 2d is implemented by an optional unit that stores sheets of a size that is consumed in a large amount. The manual feed tray 2e is configured to be able to supply special sheets such as a cardboard sheet, a coating sheet, and a film sheet which are difficult to feed separately.

It is sufficient if the image forming portion 3 is configured to form an image on the sheet S sent from the feeding portion 2, and various image forming mechanisms can be adopted. In the illustrated embodiment, an electrostatic image forming mechanism is illustrated as the image forming portion 3. However, the image forming portion 3 is not limited to the illustrated electrostatic image forming mechanism, and it is also possible to adopt an inkjet image forming mechanism, an offset image forming mechanism, or the like.

The image forming portion 3 illustrated in FIG. 1 is provided with a photosensitive member 9 formed in a drum shape or a belt shape and a light emitter 10 that emits an optical beam to the photosensitive member 9, and a developer 11 and a cleaner (not illustrated) are disposed around the rotating photosensitive member 9. FIG. 1 illustrates a monochrome printing mechanism, in which the light emitter 10 optically forms a latent image on the photosensitive member 9, and the developer 11 attaches toner to the latent image. The toner image attached to the photosensitive member 9 is transferred by a transfer charger 12 to the sheet S sent from the feeding portion 2, and is sent to a conveyance path 14 after the image transferred to the sheet S is fixed by a fixing roller 13. In addition, the image forming portion 3 is provided with a circulation path below the conveyance path 14, and after the sheet S conveyed from the conveyance path 14 is reversed by a switchback path, the sheet S is sent to the registration roller pair 8 again, an image formation is performed on a back surface of the sheet S, and the sheet S is sent to the conveyance path 14. A feeding roller 15 (so-called discharge roller) is disposed in the conveyance path 14, an opening portion 16 is formed at a terminal end of the conveyance path 14, and the feeding roller 15 feeds the sheet S from the opening portion 16 to the sheet processing apparatus B described below.

The image reading unit A2 that optically reads a document image to be formed by the image forming portion 3 is provided above the image forming unit A1 configured as described above, and the document feeding unit A3 is mounted above the image reading unit A2.

The image reading unit A2 includes a first platen 17 and a second platen 21 made of transparent glass, a reading carriage 18, a light source mounted on the reading carriage 18, a photoelectric conversion element 19, and a reduction optical system 20 configured by combining a mirror and a lens. The reading carriage 18 is scanned along the first platen 17, an image of a document placed on the first platen 17 is irradiated with light from the light source, and reflected light reflected from the image of the document is guided to the photoelectric conversion element 19 by the reduction optical system 20 to read the image. The photoelectric conversion element 19 converts image data into an electric signal and transfers the electric signal to the image forming portion 3.

The document feeding unit A3 includes a feeding tray 22, a feeding path 23, and a stacking tray 24, and conveys documents placed on the feeding tray 22 one by one along the feeding path 23, passes the documents on the second platen 21, and sends the documents to the stacking tray 24. When reading a document fed from the document feeding unit A3 and passing on the second platen 21, the reading carriage 18 is stopped below the second platen 21 in advance, and image data is generated from an image passing on the second platen 21.

Overall Configuration of Sheet Processing Apparatus

Next, an overall configuration of the sheet processing apparatus B that performs processing such as stapling and folding processing on sheets sent from the image forming apparatus A will be described with reference to FIG. 2. FIG. 2 illustrates a detailed configuration of the sheet processing apparatus B. The sheet processing apparatus B can process sheets received from a receiving portion 26, which is an inlet of a straight path 28 connected to the opening portion 16 of the image forming apparatus A, and then can stack the sheets on a first tray (first stacking tray) 49, a saddle stacking unit 131, and a second tray (second stacking tray) 71 described below. In the sheet processing apparatus B, a portion other than the first tray 49 and the second tray 71 is defined as a processing unit 200. That is, the processing unit 200 includes an apparatus housing 27, the straight path 28, a processing portion B1, and a saddle portion B2 described below.

In the illustrated apparatus, the sheets sent to the conveyance path and the straight path 28 serving as a first conveyance path are transferred from the processing portion B1 to the first tray 49 and the second tray 71 described below, or from the saddle portion B2 described below to a saddle stacking unit 131. Each apparatus includes a control portion, a communication portion, and the like as in blocks illustrating a control configuration in the entire apparatus illustrated in FIG. 3, thereby performing an apparatus control.

The processing portion B1 is disposed below a path outlet (delivery portion 35) of the straight path 28, aligns and accumulates a plurality of sheets sequentially delivered from the straight path 28 via the delivery portion 35 to form a sheet bundle, and can perform the binding processing, which is an example of predetermined processing, on an end portion of the sheet bundle. The sheet bundle subjected to the binding processing is stacked on the first tray 49 serving as a stacking portion.

The saddle portion B2 is disposed below a delivery portion of a saddle path 32 serving as a second conveyance path branching vertically downward from the straight path 28, aligns and accumulates a plurality of sheets sequentially delivered from the straight path 28 via the saddle path 32 and the delivery portion to form a sheet bundle, performs folding processing after or without performing saddle binding processing, and sends the sheet bundle to the saddle stacking unit 131. Hereinafter, each configuration will be described in detail.

Apparatus Housing

As illustrated in FIG. 2, the sheet processing apparatus B includes the apparatus housing 27, the straight path 28, the processing portion B1, the saddle portion B2, the first tray 49, the saddle stacking unit 131, the second tray 71, and the like. The straight path 28, the processing portion B1, and the saddle portion B2 are disposed inside the apparatus housing 27. The straight path 28 includes the receiving portion 26 for sheets and the delivery portion 35 for sheets. The processing portion B1 and the saddle portion B2 process the sheets delivered from the delivery portion 35 of the straight path 28. The first tray 49, the saddle stacking unit 131, and the second tray 71 stack the sheets sent from the respective processing portions. The illustrated apparatus housing 27 is connected to the apparatus housing 1 of the image forming apparatus A positioned upstream in a sheet conveyance direction in the straight path 28. The apparatus housing 27 and the apparatus housing 1 are disposed such that a height of the opening portion 16 of the image forming apparatus A from an installation surface and a height of the receiving portion 26 of the sheet processing apparatus B from the installation surface are substantially the same, and the opening portion 16 and the receiving portion 26 are connected.

Sheet Receiving Path

As illustrated in FIGS. 2 and 4, the straight path 28, which is a sheet receiving path, is implemented by a substantially linear path crossing the apparatus housing 27 in a substantially horizontal direction, and includes the receiving portion 26 connected to the opening portion (main body opening portion) 16 of the image forming apparatus A, and the delivery portion 35 positioned on an opposite side of the apparatus to the receiving portion 26. In the straight path 28, an inlet roller 29, a first conveyance roller 201, a second conveyance roller 202, and a third conveyance roller 203 serving as conveyance rollers capable of conveying a sheet in a first direction from the receiving portion 26 toward a first sending path 31 and capable of conveying a sheet in a second direction from the first sending path 31 toward the receiving portion 26 are disposed. That is, the inlet roller 29, the first conveyance roller 201, the second conveyance roller 202, and the third conveyance roller 203 can convey a sheet in the first direction and the second direction opposite to the first direction in the conveyance path, and are arranged in order from a side adjacent to the receiving portion 26 in the first direction.

The first sending path 31 is connected to the delivery portion 35 of the straight path 28, and a first conveyance roller 36 is disposed at a portion where the first sending path 31 and the delivery portion 35 are connected. The sheet delivered from the straight path 28 to the first sending path 31 and sent from the first sending path 31 is sent to the first tray 49 or guided to the processing portion B1. Each of the above-described conveyance rollers may be another member capable of conveying a sheet, such as a conveyor belt.

Layout of Sheet Receiving Path

As illustrated in FIGS. 2 and 4, the saddle path 32 and an upper conveyance path 30, which are branch paths, are connected to the straight path 28. The saddle path 32 and the upper conveyance path 30 are arranged in order from the receiving portion 26 toward the first sending path 31 in the first direction. The saddle path 32 branches vertically downward from the straight path 28, and the upper conveyance path 30 branches vertically upward from the straight path 28. A saddle path switching member 33 and an upper conveyance path switching member 34 serving as switching members for switching a conveyance direction of a conveyed sheet are disposed at respective branching portions of the straight path 28, the saddle path 32, and the upper conveyance path 30.

Branching of Path

The upper conveyance path switching member 34 is implemented by a switching member guide that is operated to change the conveyance path so as to convey the sheet received from the receiving portion 26 to either the first sending path 31 or the upper conveyance path 30, and is connected to a drive portion (not illustrated) such as an electromagnetic solenoid or a mini-motor.

Upper Conveyance Path

The upper conveyance path 30 (printout sending path) that conveys a sheet other than a sheet to be sent to the first sending path 31 is connected to the straight path 28, and the upper conveyance path switching member 34 that guides the sheet to the upper conveyance path 30 is provided at the path branching portion. In addition, the upper conveyance path 30 includes a fourth conveyance roller 204, a fifth conveyance roller 205, and a sixth conveyance roller 206 serving as conveyance rollers that guide a sheet to the second tray 71, and a second sending roller pair 207 serving as a sending portion. As a result, the sheet guided to the upper conveyance path 30 is sent from an upper conveyance path opening portion 40 to the second tray 71 (overflow tray) serving as a stacking tray (stacking portion) by the second sending roller pair 207.

The processing portion B1 includes a processing tray 37 serving as a placement portion which is disposed downstream of the straight path 28, on which a sheet sent from the first sending path 31 is placed, and which aligns and accumulates a plurality of placed sheets, and a binding processing mechanism 47 that performs the binding processing on the accumulated sheet bundle. Then, the processing portion B1 performs the binding processing on the sheet bundle placed on the processing tray 37. The binding processing mechanism 47 is disposed vertically below the straight path 28. As illustrated in FIGS. 2 and 4, a step is formed in the first sending path 31, and the processing tray 37 is disposed below the step. A first switchback path is formed between the first sending path 31 and the processing tray 37 to guide a sheet onto the processing tray 37 by reversing the conveyance direction from an opening portion 31a of the first sending path 31.

Specifically, the first sending path 31 is provided with an upper conveyance roller 41 and a lower conveyance roller 48 that nip and convey a sheet. The upper conveyance roller 41 and the lower conveyance roller 48 form a sending roller pair 42 serving as a sending portion. The upper conveyance roller 41 can abut on and be separated from the lower conveyance roller 48, and can convey a sheet in a direction toward the first tray 49 and in a direction opposite to the direction in a state in which the upper conveyance roller 41 and the lower conveyance roller 48 nips the sheet. Then, the sheet can be conveyed toward the processing tray 37 via the first switchback path by the upper conveyance roller 41 and the lower conveyance roller 48. In addition, the upper conveyance roller 41 and the lower conveyance roller 48 (that is, the sending roller pair 42) send the sheet or the sheet bundle on the processing tray 37 from the opening portion 31a to the first tray 49 serving as a stacking tray (stacking portion). The opening portion 31a is a portion opened above the lower conveyance roller 48 of the apparatus housing 27. Further, the sending roller pair 42 sends the sheet conveyed to the first sending path 31 without passing through the processing tray 37 from the opening portion 31a to the first tray 49.

The binding processing mechanism 47 includes a trailing edge regulating portion 47a that abuts on an edge portion (trailing edge) of a sheet to position the sheet. A reversing portion 38 for conveying the sheet conveyed to the processing tray 37 by the upper conveyance roller 41 and the lower conveyance roller 48 toward the trailing edge regulating portion 47a is disposed above the processing tray 37. Then, the binding processing mechanism 47 performs the binding processing on an end portion of a sheet bundle including a plurality of sheets of which positions of end portions are regulated by the trailing edge regulating portion 47a, the sheet bundle being placed on the processing tray 37. The binding processing mechanism 47 includes a sheet bundle carrying-out mechanism that carries out the sheet bundle to the first tray 49 after performing the binding processing on the end portion of the sheet bundle.

The binding processing mechanism 47 illustrated in FIG. 2 supports the sheet sent from the first sending path 31 such that the sheet straddles between the processing tray 37 and the first tray 49 positioned downstream of the processing tray 37. That is, the leading edge of the sheet sent from the first sending path 31 is supported on the uppermost sheet of the first tray 49 positioned downstream, and a trailing edge portion of the sheet is supported on the processing tray 37.

Saddle Path

The saddle path 32 for conveying a sheet to the above-described saddle portion B2 is connected to the straight path 28, and the saddle path switching member 33 for guiding a sheet to the saddle path 32 is provided at the path branching portion. A sheet guided to the saddle portion B2 by the saddle path 32 is subjected to center-folding processing and then sent to the saddle stacking unit 131 via a post-folding path guide 114 arranged in the substantially horizontal direction, a second post-roller path guide 116, and a saddle sending guide 124. In the present embodiment, the saddle sending guide 124 is used as an auxiliary guide for appropriately stacking the sheet on the saddle stacking unit 131.

Control Configuration

An outline of a control configuration of the image forming system 1000 will be described with reference to FIG. 3. First, the image forming apparatus A includes the control portion 310, an operation portion 302, a conveyance control portion 303, an image processing portion 304, a drive portion 305, and a communication portion 306. The control portion 310 includes a central processing unit (CPU) 311, a read only memory (ROM) 312, and a random access memory (RAM) 313. The CPU 311 controls each portion while reading a program corresponding to a control procedure stored in the ROM 312. In addition, work data and input data are stored in the RAM 313, and the CPU 311 performs a control with reference to the data stored in the RAM 313 based on the above-described program or the like.

The operation portion 302 is, for example, an operation panel connected to the control portion 310 and provided in the image forming apparatus A, and the operator operates the apparatus and performs various settings by using the operation portion 302. The conveyance control portion 303 controls various conveyance rollers that convey a sheet in the image forming apparatus A and a switching member that switches a conveyance path. The image processing portion 304 controls the image forming portion 3. The drive portion 305 controls various motors and power supplies. The communication portion 306 communicably connects an external device 301 such as a personal computer or a communication portion 321 of the sheet processing apparatus B and the control portion 310.

The sheet processing apparatus B includes a stacker control portion 330, a conveyance control portion 322, an end portion binding control portion 323, a sending processing control portion 324, and the communication portion 321. As illustrated in FIGS. 10 and 13 described below, the above-described portions are provided on a circuit board 500 disposed inside the apparatus housing 27 of the processing unit 200. A housing portion 501 in which the circuit board 500, a power supply, and the like are housed is provided on a back side of the apparatus housing 27. The circuit board 500 may be a control board that controls a lifting/lowering operation of the first tray 49 or the like, or may be a relay board that relays to a control board.

Similarly to the control portion 310, the stacker control portion 330 includes a CPU 331, a ROM 332, and a RAM 333. The conveyance control portion 322 controls various conveyance rollers that convey a sheet and a switching member that switches a conveyance path in a portion other than the saddle portion B2 of the sheet processing apparatus B. The end portion binding control portion 323 controls the processing portion B1. The sending processing control portion 324 controls sending of a sheet and various stacking trays on which the sent sheet is stacked. The communication portion 321 communicably connects the communication portion 306 of the image forming apparatus A and the communication portion 341 of the saddle portion B2, and the stacker control portion 330. Communication between the communication portion 306 and the communication portion 321 may be performed by wired communication or wireless communication.

The communication portion 321 functions as a notification portion, and in a case where it is detected that there is a sheet on the stacking tray such as the first tray 49 or the second tray 71, the communication portion 321 notifies that there is a sheet as described below. Specifically, information indicating that there is a sheet is transmitted to the communication portion 306 of the image forming apparatus A, and for example, information indicating that there is a sheet is displayed on a display portion of the operation portion 302.

The saddle portion B2 includes a saddle control portion 350, a conveyance control portion 342, a saddle binding control portion 343, a center-folding control portion 344, and a communication portion 341. Similarly to the control portion 310, the saddle control portion 350 includes a CPU 351, a ROM 352, and a RAM 353. The conveyance control portion 342 controls various conveyance rollers that convey a sheet in the saddle portion B2 and a switching member that switches a conveyance path. The saddle binding control portion 343 controls a saddle binding processing portion 104. The center-folding control portion 344 controls a center-folding processing mechanism C1. The communication portion 341 communicably connects the communication portion 321 of the sheet processing apparatus B and the saddle control portion 350.

Saddle Portion

As illustrated in FIG. 2, the saddle portion B2 includes the center-folding processing mechanism C1. The center-folding processing mechanism C1 aligns and accumulates sheets sent from the straight path 28 to form a sheet bundle, performs the binding processing on a central portion of the sheet bundle in the conveyance direction, and performs center-folding processing of folding the sheet bundle at a position where the binding processing has been performed. Then, the saddle stacking unit 131 is disposed downstream of the center-folding processing mechanism C1, and stores the sheet bundle subjected to bookbinding processing. It is also possible to align and accumulate one sheet or a plurality of sheets, and perform only the center-folding processing of folding the central portion of the sheet in the conveyance direction without performing the saddle binding processing.

Details of Sheet Stacking Configuration

A sheet stacking configuration of the sheet processing apparatus B according to the present embodiment will be described in detail with reference to FIGS. 5 to 17. As described above, the sheet processing apparatus B includes the apparatus housing 27, the processing unit 200 including the sending roller pair 42 and the second sending roller pair 207 serving as sending portions, the first tray 49 and the second tray 71 serving as stacking trays, and the like. The sheet processing apparatus B further includes a lifting/lowering mechanism 210 that moves up and down the first tray 49 and the second tray 71, and a sheet presence/absence detection mechanism 220 that detects the presence/absence of a sheet on each of the first tray 49 and the second tray 71. Since configurations of the lifting/lowering mechanism 210 and the sheet presence/absence detection mechanism 220 are similar between the first tray 49 and the second tray 71, only those for the first tray 49 will be described below.

First, a configuration around the opening portion 31a through which a sheet is sent from the apparatus housing 27 to the first tray 49 will be described with reference to FIG. 5. The configuration around the opening portion 31a described below is similar to a configuration around the upper conveyance path opening portion 40. An abutment member 271 against which a trailing edge (an upstream end portion in a sending direction) of a sent sheet abuts is provided between the first tray 49 and the processing portion B1 below the opening portion 31a on an outer surface of the apparatus housing 27. The abutment member 271 serves to align conveyance directions of sheets sent onto and stacked on the first tray 49.

In addition, a stacking surface 49a of the first tray 49 on which sheets are stacked is gradually inclined in a downward direction toward the abutment member 271, the sheets sent from the opening portion 31a slide down along the inclination of the stacking surface 49a after falling onto the first tray 49, and trailing edges of the sheets reach the abutment member 271 and stop.

In addition, the first sending path 31 can include a width direction alignment portion 272 that performs alignment of sheets in a width direction intersecting a sheet sending direction, and a sending direction alignment portion 274 that performs alignment in the sheet sending direction. The width direction alignment portion 272 is provided above the first tray 49. The width direction alignment portion 272 includes a pair of alignment members 273a and 273b that are movable in a vertical direction and movable in the width direction. A recess 49b into which the alignment members 273a and 273b can enter when the alignment members 273a and 273b are lowered is formed in the stacking surface 49a of the first tray 49. FIG. 5 illustrates a state in which the alignment members 273a and 273b are retracted upward from a nip point of the upper conveyance roller 41 and the lower conveyance roller 48, and sheets are sent from the opening portion 31a in this state. Then, when the sheet is sent to the first tray 49, the alignment members 273a and 273b are lowered until the alignment members 273a and 273b partially enter the recess 49b and hit both end portions of the sheets in the width direction from both sides of the sheets in the width direction. Accordingly, the alignment of the sheets in the width direction is performed.

On the other hand, the sending direction alignment portion 274 includes a paddle 275 serving as a conveyance portion that is movable in the vertical direction and can rotate to convey sheets on the first tray 49 in a direction opposite to the sending direction. The paddle 275 is disposed above the first tray 49, and is movable to a conveyance position where the paddle 275 comes into contact with the sheets on the first tray 49 to convey the sheets upstream in the sheet sending direction, and a retraction position where the paddle 275 is retracted upward from the conveyance position.

FIG. 5 illustrates a state in which the paddle 275 is retracted upward from the opening portion 31a (a state in which the paddle 275 is in the retraction position), and sheets are sent from the opening portion 31a in this state. Then, when the sheets are sent to the first tray 49, the paddle 275 is lowered toward the conveyance position, and the paddle 275 rotates to convey the sheets sent from the opening portion 31a toward the abutment member 271 while dropping the sheets onto the first tray 49.

Lifting/Lowering Mechanism

Next, the lifting/lowering mechanism 210 of the first tray 49 will be described with reference to FIGS. 6 to 8. FIG. 6 is a view illustrating the lifting/lowering mechanism 210 of the first tray 49 taken out from the sheet processing apparatus B, and FIGS. 7 and 8 are enlarged views of the periphery of a drive portion 211 of the lifting/lowering mechanism 210. When sending sheets to the first tray 49 or the second tray 71 serving as the stacking tray, it is necessary to move up and down the first tray 49 or the second tray 71 in order to keep the position of the stacking surface 49a or the uppermost sheet on the stacking surface 49a constant, so that the proper alignment of the stacked sheets is ensured. Therefore, in the present embodiment, the first tray 49 or the second tray 71 is lowered by a tray motor 190 serving as a lifting/lowering portion such that the height of the uppermost sheet among sheets sent by the sending roller pair 42 or the second sending roller pair 207 and stacked on the first tray 49 or the second tray 71 falls within a predetermined range, and the first tray 49 or the second tray 71 is lifted when the sheets stacked on the first tray 49 or the second tray 71 are removed. Since the operations of the first tray 49 and the second tray 71 are the same, the first tray 49 will be described below as an example.

The lifting/lowering mechanism 210 according to the present embodiment adopts a system of driving by a belt, and includes a first belt 80, a first pulley 81, a drive shaft 82, gears 83 to 87, a second pulley 88, a second belt 89, the tray motor 190, and the like. The first tray 49 is held by two first belts 80 on both sides in the width direction. Drive transmission of the two first belts 80 is performed by two upper and lower first pulleys 81 disposed in a substantially vertical direction and attached to a frame of the apparatus housing 27. The two first belts 80 are driven by the tray motor 190 serving as the lifting/lowering portion via the drive shaft 82 to move up and down the first tray 49.

That is, the pulley 88 rotates via the second belt 89 by the drive of the tray motor 190, and the rotation of the pulley 88 is transmitted to the coaxially arranged gears 87 and 86. Then, the rotation of the gear 86 is transmitted to the coaxially arranged gears 85 and 84, and the rotation is further transmitted from the gear 84 to the gear 83 provided at an end portion of the drive shaft 82. The drive shaft 82 is disposed so as to straddle the two first belts 80, and transmits the drive of the tray motor 190 disposed on the right side of FIG. 6 to the left first belt 80. As a result, the two first belts 80 are rotationally driven by the tray motor 190, and the first tray 49 held by the two first belts 80 moves up and down. The first tray 49 moves along a rail (not illustrated) provided in the apparatus housing 27 in a substantially vertical direction. A motor serving as the lifting/lowering portion that moves up and down the first tray 49 may be disposed on the first tray 49.

As illustrated in FIGS. 7 and 8, a torque limiter 180 which is an overload protection device is attached to shafts of the gear 86 and the gear 87 via a gear 191, and supports the weight of the sheet bundle stacked on the first tray 49. As a result, the torque limiter 180 performs sliding rotation at the time of overloading to prevent the first tray 49 and drive components from being damaged. Further, an engagement portion between the gear 84 and the gear 85 is a ratchet, and when a foreign substance or a hand of a worker is caught when the first tray 49 is lifted, the drive can be disconnected between the gear 84 and the gear 85. As a result, there are effects of preventing damage to the first tray 49 and the drive components and preventing worker's injuries.

Further, as illustrated in FIG. 8, an encoder 520 is attached on the drive shaft 82. As a tray position detection sensor S10 detects ON/OFF of the encoder 520, the stacker control portion 330 can detect a rotation amount of the first tray motor 190, that is, a movement amount of the first tray 49. The tray position detection sensor S10 is provided in the apparatus housing 27, and is electrically connected to the circuit board 500 (see FIG. 10 or the like described below) of the sheet processing apparatus B via a wiring (not illustrated).

Detection of Upper Surface of Sheet

Next, a configuration of an upper surface detection portion 502 for detecting an upper surface of a sheet stacked on the first tray 49 will be described with reference to FIGS. 9 to 12. The detection of the upper surface of the sheet is performed to detect a position of an upper surface of the uppermost sheet among a plurality of sheets stacked on the first tray 49. FIG. 9 is a perspective view illustrating the first tray 49, the sending roller pair 42, the abutment member 271, and the upper surface detection portion 502 in an extracted manner. FIG. 10 is a view when viewed downstream in the sheet sending direction from the opening portion 31a. FIGS. 11 and 12 are views of an upstream end portion side of the first tray 49 when viewed from the back to the front of the apparatus, in which FIG. 11 illustrates a state in which there is no sheet on the first tray 49, and FIG. 12 illustrates a state in which there is a sheet on the first tray 49.

As illustrated in FIG. 9, the upper surface detection portion 502 includes a light emitting portion 510d, and first to third light receiving portions 510a, 510b, and 510c that can receive light emitted from the light emitting portion 510d. The light emitting portion 510d is disposed on one side of the stacking surface 49a on which the sheet of the first tray 49 is stacked in the width direction of the sheet intersecting the sending direction. On the other hand, the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c are disposed on the other side of the stacking surface 49a in the width direction.

In the illustrated example, notches 49c are formed in portions close to end portions on both sides of the first tray 49 in the width direction, respectively, and when the first tray 49 moves up and down, a light emitting portion 510d can pass through the notch 49c on one side in the width direction, and the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c can pass through the notch 49c on the other side in the width direction. The light emitting portion 510d may be disposed on one side of the first tray 49 in the width direction, and the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c may be disposed on the other side of the first tray 49 in the width direction.

The light emitting portion 510d, the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c are provided in the apparatus housing 27 of the processing unit 200, and are electrically connected to the circuit board 500 of the sheet processing apparatus B by a wiring 503 serving as a wiring portion as illustrated in FIG. 10. Specifically, as illustrated in FIG. 3, the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c (collectively illustrated as “light receiving portion” in FIG. 3) are connected to the circuit board 500 via an output portion 325.

The output portion 325 outputs an electric signal according to light receiving states of the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c. The output portion 325 “outputs” an electric signal not only at the time of light transmission (at the time when the light receiving portion receives light) but also “zero” at the time of light blocking. As described below, in the present embodiment, it is determined that there is a sheet on the first tray 49 when the second light receiving portion 510b is shielded from light, but it may be determined that there is no sheet on the first tray 49 when the second light receiving portion 510b is shielded from light.

The electric signal output from the output portion 325 is received by an interface portion 326 serving as a reception portion. The stacker control portion 330 serving as the determination portion determines the presence or absence of a sheet on the first tray 49 (on the stacking portion) according to the electric signal received by the interface portion 326 as described below. The output portion 325 and the interface portion 326 are connected by the wiring 503 provided in the processing unit 200. Hereinafter, the “detection” by various sensors such as the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c means that various control potions such as the stacker control portion 330 determine a state of an object to be detected by the sensor based on an electric signal output according to the state of the sensor.

The light emitting portion 510d, the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c are arranged downstream of the opening portion 31a and in the vicinity of the abutment member 271. In addition, the number of light emitting portions 510d is one, and the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c are arranged side by side in a lifting/lowering direction of the first tray 49 (a height direction and a substantially vertical direction) in a range capable of receiving light emitted from the light emitting portion 510d (an irradiation range a of the light emitting portion 510d illustrated in FIG. 10) (see FIGS. 11 and 12). Specifically, the second light receiving portion 510b at the center in the height direction is disposed at substantially the same height position as the light emitting portion 510d, the first light receiving portion 510a is disposed above the second light receiving portion 510b, and the third light receiving portion 510c is disposed below the second light receiving portion 510b.

The position of the first tray 49 in the height direction is controlled by detecting the first tray 49 or the sheet stacked on the first tray 49 by the above-described upper surface detection portion 502. As illustrated in FIGS. 3 and 10, an ON/OFF signal (electric signal) of each light receiving portion is output from the output portion 325 depending on light has been emitted from the light emitting portion 510d and whether or not the first light receiving portion 510a, the second light receiving portion 510b, and the third light receiving portion 510c have received the light. In the present embodiment, the ON signal is output in a case where the light receiving portion has not received light (in a case where the light receiving portion is shielded), and the OFF signal is output in a case where the light receiving portion has received light. Then, a detection signal (electric signal) is transmitted to the interface portion 326 of the circuit board 500 via the wiring 503, and the stacker control portion 330 provided on the circuit board 500 controls the height position of the first tray 49 by controlling the tray motor 190 via the sending processing control portion 324 (FIG. 3) based on the signal.

Here, the second light receiving portion 510b at the center is a sensor for detecting the upper surface of the sheet on the first tray 49 (also referred to as a sheet upper surface detection sensor or a sheet surface detection sensor). As illustrated in FIG. 12, the first light receiving portion 510a positioned above is a sensor for detecting that a trailing edge of a sheet S1 sent onto the first tray 49 leans against the abutment member 271 (trailing edge leaning). Since the light emitting portion 510d is positioned at substantially the same height as the second light receiving portion 510b as described above, light emitted from the light emitting portion 510d and received by the first light receiving portion 510a positioned above the second light receiving portion 510b is shielded by the sheet S1 on the first tray 49, and the first light receiving portion 510a is turned on. As illustrated in FIG. 12, for example, the third light receiving portion 510c positioned below is a sensor for detecting that a sheet bundle S2 is stacked on the first tray 49 during execution of a job and the sheet bundle S2 is suddenly removed in a state in which the first tray 49 is lowered. That is, the third light receiving portion 510c is normally in a state (ON state) of being shielded from light by the first tray 49 or the sheet, but when the sheet bundle S2 is removed, the third light receiving portion 510c receives light emitted from the light emitting portion 510d and is turned off.

The stacker control portion 330 (FIG. 3) according to the present embodiment positions the first tray 49 at a position where the second light receiving portion 510b is shielded by the first tray 49 and the sheet bundle S2 on the stacking surface 49a before the start of a job, after the end of a job, and at the time of full load (FIG. 39). FIG. 39 illustrates a state in which the first tray 49 is positioned at a position where the second light receiving portion 510b is shielded by the sheet bundle S2 on the stacking surface 49a. Therefore, in a case where the sheet bundle S2 on the first tray 49 is removed by the user after the end of a job, the second light receiving portion 510b receives light emitted from the light emitting portion 510d and transitions from a state (ON state) of being shielded from light by the sheet bundle S2 to an OFF state. On the other hand, during the execution of a job, the first tray 49 is positioned at a position (a sheet reception position described below) where the second light receiving portion 510b is in the OFF state and the third light receiving portion 510c is in the ON state.

In FIG. 11, the first tray 49 is at the sheet reception position where a sheet sent from the sending roller pair 42 in a state in which no sheet is stacked is received on the first tray 49. The sheet reception position changes according to the number of sheets stacked on the first tray 49. For example, in a case where a plurality of sheets are stacked on the first tray 49, the first tray 49 is moved to a position where a sheet can be sent onto the uppermost sheet.

Thereafter, when a job is executed and sheets are sequentially stacked on the first tray 49, the second light receiving portion 510b is shielded from light by the sheets and is turned on. When the second light receiving portion 510b is turned on, the tray motor 190 is driven to lower the first tray 49 to the sheet reception position by a predetermined distance (for example, 1 mm) from a position where the second light receiving portion 510b is turned off (a position where light from the light emitting portion 510d is received). That is, in the present embodiment, the sheet reception position is a position lowered by a predetermined distance from a position where the second light receiving portion 510b is turned off. However, the sheet reception position only needs to be set according to the state of the second light receiving portion 510b, and may be, for example, a position where the second light receiving portion 510b is turned off.

In this manner, the sheets are sequentially stacked on the first tray 49 by repeatedly performing an operation of lowering the first tray 49 when the sheets are stacked on the first tray 49 and the second light receiving portion 510b is turned on. Specifically, when the sheets are stacked on the first tray 49, the stacker control portion 330 checks the state of the second light receiving portion 510b once every time five sheets are stacked. Then, when the second light receiving portion 510b is turned on (shielded from light by the stacked sheets), the first tray 49 is lowered to the sheet reception position by 1 mm from the position where the second light receiving portion 510b is turned off (light receiving state). In the case of bundle sending in which a sheet bundle is sent by the sending roller pair 42, the stacker control portion 330 checks the state of the second light receiving portion 510b every time, and similarly lowers the first tray 49 based on the ON/OFF signal of the second light receiving portion 510b.

In the present embodiment, the state of the second light receiving portion 510b is checked every time a predetermined number of sheets are stacked (every time five sheets are stacked in the above example), and the first tray 49 is lowered in a case where the second light receiving portion 510b is shielded from light. However, the predetermined number may be another number such as one, or the predetermined number may be changed according to a sheet grammage. In addition, the state of the second light receiving portion 510b may be monitored without counting the number of sheets, and the first tray 49 may be lowered when the second light receiving portion 510b is shielded from light. That is, the state of the second light receiving portion 510b may be constantly monitored. A timing of monitoring the state of the second light receiving portion 510b may be changed to lower the first tray 49. For example, in the first time after a job is executed, the state of the second light receiving portion 510b may be checked every time five sheets are stacked, and in the second and subsequent times, the state of the second light receiving portion 510b may be checked every time four sheets are stacked, and the first tray 49 may be lowered when the second light receiving portion 510b is shielded from light.

In addition, the first tray 49 may be lowered every time the predetermined number of sheets are stacked by counting the number of sheets without checking the state of the second light receiving portion 510b. Also in this case, the predetermined number may be another number such as one, or the predetermined number may be changed according to the sheet grammage. Furthermore, in a case where the first tray 49 is lowered by counting the number of sheets without checking the state of the second light receiving portion 510b, the number of sheets for lowering the first tray 49 may be changed. For example, in the first time after a job is executed the first tray 49 may be lowered every time five sheets are stacked, and in the second time, the first tray 49 may be lowered every time six sheets are stacked.

In a case where the first tray 49 is lowered to an allowable stacking height, the stacker control portion 330 notifies the image forming apparatus A that the amount of sheets stacked on the first tray 49 has reached an upper limit (that is, full load detection) via the stacker control portion 330 and the communication portion 321. At this time, the first tray 49 is lifted, and the operation is temporarily stopped in a state (ON state) where the second light receiving portion 510b is shielded from light by the sheets on the first tray 49. In this case, the first tray 49 is positioned in the vicinity of a lower limit of a lifting/lowering area, and the stacker control portion 330 starts an operation of lifting the first tray 49 at a time point when it is detected that the second light receiving portion 510b is turned off as the operator removes the sheet bundle on the first tray 49. Thereafter, the first tray 49 is once lifted and stopped until the second light receiving portion 510b is turned on.

In a case where the third light receiving portion 510c is turned off not in a full load state, but in a state in which sheets are being stacked on the first tray 49 during execution of a job, the stacker control portion 330 determines that a certain amount of sheets have been removed from the first tray 49. Then, the first tray 49 is once lifted and stopped until the second light receiving portion 510b is turned on, and is lowered to the sheet reception position by 1 mm from the position where the second light receiving portion 510b is turned off, and stopped. A lowering amount of the first tray 49 can be detected by a detection signal of the tray position detection sensor S10 illustrated in FIG. 8. The stacker control portion 330 can grasp how much the first tray 49 has been lowered from an initial position at the start of the job, for example, based on the detection signal of the tray position detection sensor S10.

Detection of Height Position of Tray

Next, a configuration and an operation for detecting the position (height position) of the first tray 49 in the lifting/lowering direction will be described with reference to FIGS. 13 to 15. As illustrated in FIGS. 13 and 14, area detection sensors S11 to S20 serving as height detection portions are arranged in a substantially vertical direction in the vicinity of the first belt 80 that moves up and down the first tray 49. The area detection sensors S11 to S20 are provided in the apparatus housing 27 of the processing unit 200, and are electrically connected to the circuit board 500 of the sheet processing apparatus B by a wiring (not illustrated).

Each of the area detection sensors S11 to S20 is a photointerrupter in which a light emitting portion and a light receiving portion are disposed to face each other with a gap therebetween, and a shielding plate (flag) 192 can pass through the gap. The shielding plate 192 is provided on the first tray 49 and moves up and down together with the first tray 49. Then, when the shielding plate 192 enters a gap between one or more of the area detection sensors S11 to S20, the one or more sensors enter a detection state (ON).

The area detection sensor S12 is a reference position detection portion (home position sensor) disposed at a position where a reference position (HP) in the lifting/lowering direction of the first tray 49 can be detected, and in a case where the first tray 49 is at this position, the area detection sensor S12 enters the detection state (ON), and in a case where the first tray 49 is below this position, the area detection sensor S12 enters a non-detection state (OFF). The reference position is positioned above the above-described sheet reception position. Each of the area detection sensors S11 and S13 to S20 is disposed at an interval from the area detection sensor S12 (HP). The distance between each sensor and the area detection sensor S12 corresponds to a height of the sheet bundle stacked on the first tray 49 to be detected, and the height position of the first tray 49, that is, the height of the sheet bundle on the first tray 49, can be detected from the detection state of each sensor.

The area detection sensor S11 at the top in FIG. 13 is an upper limit detection sensor for the first tray 49, and when the shielding plate 192 is detected by the area detection sensor S11, the lifting/lowering operation is restricted such that the first tray 49 is not further lifted. The area detection sensor S11 may be disposed at a position below the area detection sensor S12 that detects the home position (HP) and above the area detection sensor S13. In this case, for example, it is determined that the first tray 49 has reached the upper limit at a timing when a lower end portion of the shielding plate 192 passes the area detection sensor S11 or at a timing when the lower end portion is lifted by a certain distance from the timing.

Further, the shielding plate 192 is provided at a position detected by the above-described area detection sensors S11 to S20 during the lifting/lowering operation of the first tray 49, and has a predetermined length in the substantially vertical direction. The predetermined length of the shielding plate 192 is set to be longer than the second longest interval among the intervals between the area detection sensors S11 to S20. As illustrated in FIG. 15 as an example, assuming that the length of the shielding plate 192 is Lf and the intervals between the sensors are L1, L2, and L3 in the order of length, the length of the shielding plate 192 is set such that L1>Lf>L2>L3. Each of SEN A to SEN D in FIG. 15 indicates any of the area detection sensors S11 to S20. By setting the length of the shielding plate 192 and the interval between the respective sensors in this manner, it is possible to detect at which height (area) the first tray 49 is positioned according to a pattern in which the shielding plate 192 passes the area detection sensors S11 to S20 and the area detection sensors S11 to S20 are turned on/off, without vertically moving the first tray 49.

As described above, the sheet processing apparatus B is provided with two types of configurations for detecting the height positions of the first tray 49 and the second tray 71 serving as the stacking trays. One is that the encoder 520 and the tray position detection sensor S10 can detect the amount of fine movement of the stacking tray. The other is that the area detection sensors S11 to S20 and the shielding plate 192 can grasp how much the stacking tray has been lowered. The detection by the encoder 520 enables detection of the amount of fine movement, but there is a risk that the actual movement amount deviates from a detection amount due to backlash of the drive portion when the lifting/lowering is repeated. On the other hand, the detection by the shielding plate 192 has an advantage that it is possible to reliably detect that the stacking tray has been lowered to a predetermined position. The lifting/lowering operation, control, position detection, and the like of the first tray 49 have been described above, and the same applies to the second tray 71.

Sheet Presence/Absence Detection Mechanism

Next, the sheet presence/absence detection mechanism 220 that detects the presence or absence of a sheet on the stacking tray will be described with reference to FIGS. 16 and 17 while referring to FIG. 11 described above. Hereinafter, the detection of the presence or absence of a sheet on the first tray 49 will be described, but the same applies to the second tray 71.

The sheet presence/absence detection mechanism 220 detects the presence/absence of a sheet on the first tray 49, and includes a moving member (flag) 193 serving as a displacement portion and a detection portion 221. The moving member 193 is provided on the first tray 49 and can be displaced according to the presence or absence of a sheet on the first tray 49. In the present embodiment, the moving member 193 is movable to a first position in a case where there is no sheet on the first tray 49, and is movable to a second position in a case where there is a sheet on the first tray 49 by coming into contact with the sheet. That is, a posture of the moving member 193 changes depending on whether or not there is a sheet or a sheet bundle on the first tray 49. For example, it is sufficient if the moving member 193 of the sheet presence/absence detection mechanism 220 in the present embodiment is a member that is movable in a case where a sheet having a grammage of 45 g/m²is placed on the first tray 49, and in a case where a sheet having a grammage of 45 g/m²or more is on the first tray 49, it is detected that there is a sheet on the first tray 49. Therefore, the moving member 193 includes a moving member that does not move for a sheet having a small grammage such as a sheet having a grammage of less than 45 g/m². However, a lower limit of the sheet grammage that can be detected by the moving member 193 can be appropriately changed according to design.

The detection portion 221 is provided in the apparatus housing 27 of the processing unit 200, is electrically connected to the circuit board 500 via the output portion 325 by the wiring 503, and detects a position of the moving member 193 in a state in which the first tray 49 is at a predetermined position. That is, the output portion 325 can output an electric signal according to the displacement of the moving member 193 in a state in which the first tray 49 is at the predetermined position. In the present embodiment, the detection portion 221 is also used as the upper surface detection portion 502 described above. That is, the detection portion 221 includes the light emitting portion 510d and the second light receiving portion 510b in the configuration of the upper surface detection portion 502. Hereinafter, each configuration will be described in detail.

As illustrated in FIG. 17, the moving member 193 includes a contact portion 193a and a detection target portion 193c. The contact portion 193a is a portion that can come into contact with a sheet. The contact portion 193a protrudes upward from the stacking surface 49a of the first tray 49 on which a sheet is stacked at the first position as illustrated in FIG. 16, and moves to the second position as a sheet is stacked on the stacking surface 49a. The moving member 193 is disposed inside the first tray 49, and a through hole 49d from which the contact portion 193a can protrude is formed in the stacking surface 49a of the first tray 49.

The detection target portion 193c is a portion that can be detected by the detection portion 221 by interlocking with the movement of the contact portion 193a. The detection target portion 193c has a constant area and a planar shape in the lifting/lowering direction. In a case where the moving member 193 is at the second position, it is possible to block light passing between the light emitting portion 510d and the second light receiving portion 510b included in the detection portion 221. A through hole 49e through which the detection target portion 193c is exposed to the outside upstream of the first tray 49 in the sending direction is formed below the stacking surface 49a at an upstream end portion of the first tray 49 in the sheet sending direction.

In the present embodiment, as illustrated in FIG. 17, the moving member 193 is a swing member further including a swing support portion 193b swingably supported by the first tray 49. The contact portion 193a is provided on one side of the swing support portion 193b, and the detection target portion 193c is provided on the other side of the swing support portion 193b. Therefore, at the first position where the contact portion 193a protrudes upward from the stacking surface 49a, the detection target portion 193c is positioned below a position detectable by the detection portion 221. On the other hand, in a case where the contact portion 193a comes into contact with a sheet stacked on the stacking surface 49a and moves to the second position, the moving member 193 swings about the swing support portion 193b, so that the detection target portion 193c moves upward from the position at the first position.

The position of the center of gravity of the moving member 193 is closer to the detection target portion 193c than the swing support portion 193b, such that the moving member 193 according to the present embodiment is at the first position in a state in which a sheet is not in contact with the contact portion 193a. At the first position, a projection 193d provided on the moving member 193 abuts on an inner wall of the first tray 49, and a posture thereof is maintained. When a sheet is stacked on the first tray 49 and comes into contact with the contact portion 193a, the contact portion 193a is lowered by the weight of the sheet, and the moving member 193 moves to the second position.

A part of the moving member 193 may be urged by an urging member such as a spring in a direction in which the moving member 193 moves to the first position. In addition, the moving member 193 is not limited to such a swinging member, and may have a configuration in which the contact portion 193a moves in a direction in which the contact portion 193a protrudes from the stacking surface 49a and retracts downward from a protruding position, and the movement is transmitted to the detection target portion 193c by, for example, a link mechanism.

Here, in a case where a sensor such as a photointerrupter for detecting the presence or absence of a sheet is disposed on the first tray 49, it is necessary to electrically connect the circuit board 500 on a processing unit 200 side of the sheet processing apparatus B and the sensor outside the processing unit 200 by a wiring. In this case, the wiring is arranged so as to straddle the first tray 49 and the processing unit 200. Since the first tray 49 moves up and down as described above, the wiring is required to withstand repeated lifting/lowering operations, which leads to an increase in cost. Specifically, the cost for securing a high strength of the wiring itself in order to suppress disconnection of the wiring increases, and the cost for a portion for guiding the wiring also increases.

Therefore, in the present embodiment, as described above, the moving member 193 whose posture changes depending on whether or not there is a sheet or a sheet bundle on the first tray 49 is provided on the first tray 49, but the detection portion 221 that detects the movement of the moving member 193 is provided on the processing unit 200 (specifically, the apparatus housing 27) side. By providing the detection portion 221 on the processing unit 200 side, the wiring connecting the detection portion 221 and the circuit board 500 can be arranged only on the processing unit 200 side, and disconnection of the wiring can be suppressed. That is, it is possible to suppress disconnection of the wiring connecting the sensor for detecting the presence or absence of a sheet on the first tray 49 that can move up and down and the circuit board while avoiding complication of the configuration. In addition, the cost required for securing the strength of the wiring or guiding the wiring can be made lower than a case where the wiring is arranged so as to straddle the first tray 49 and the processing unit 200. In particular, in the present embodiment, the cost can be further reduced by using the detection portion 221 also as a sensor that detects the upper surface of the sheet.

In this manner, the detection portion 221 that detects the moving member 193 includes the light emitting portion 510d and the second light receiving portion 510b of the upper surface detection portion 502. The light emitting portion 510d and the second light receiving portion 510b are disposed on both sides in the width direction so as to sandwich the stacking surface 49a of the first tray 49. Then, in a case where the moving member 193 is at one of the first position and the second position (that is, in any one of a case where there is no sheet and a case where there is a sheet on the first tray 49) and the first tray 49 is at the predetermined position, the detection target portion 193c which is a part of the moving member 193 blocks light such that light emitted from the light emitting portion 510d is not received by the second light receiving portion 510b. In the present embodiment, the detection target portion 193c is configured to block light when the moving member 193 is at the second position.

The above-described predetermined position is a position at which the detection target portion 193c blocks light emitted from the light emitting portion 510d when the moving member 193 is at one of the first position and the second position (the second position in the present embodiment) in a case where the first tray 49 is at the predetermined position in the lifting/lowering direction. In the present embodiment, the first tray 49 is positioned higher than the reference position of the first tray 49 by a predetermined distance. Therefore, in a case where the first tray 49 is below the predetermined position, the detection portion 221 functions as the upper surface detection portion 502 that detects the first tray 49 or the sheet stacked on the first tray 49. That is, in a case where the first tray 49 is below the predetermined position, the output portion 325 outputs an electric signal according to the first tray 49 or the sheet stacked on the first tray 49. The stacker control portion 330 determines the position of the stacking surface 49a of the first tray 49 or the position of the upper surface of the uppermost sheet among a plurality of sheets stacked on the stacking surface 49a according to the electric signal output from the output portion 325.

In the present embodiment, the detection portion 221 is a transmissive sensor in which the light emitting portion 510d and the second light receiving portion 510b are disposed on both sides with the moving member 193 interposed therebetween, but may be a reflective sensor. In a case of the transmissive sensor, the second light receiving portion 510b is turned on in a state in which the second light receiving portion 510b does not receive light. On the other hand, in a case of the reflective sensor, the light emitting portion 510d and the second light receiving portion 510b are disposed on one side of the moving member 193, and light emitted from the light emitting portion 510d is reflected by the detection target portion 193c of the moving member 193 and received by the second light receiving portion 510b. Then, the second light receiving portion 510b is turned on in a state in which the second light receiving portion 510b receives light.

Sheet Sending Control

Here, sheet sending control in the sheet processing apparatus B according to the present embodiment will be described with reference to FIG. 18 while referring to FIG. 3 and the like. In the image forming system 1000 according to the present embodiment, a “mixing prohibition mode” can be set in order to prevent a stacking failure or page missing that occurs in a case where sheets are stacked on the first tray 49 in a state in which all or some sheets on the first tray 49 are left on the first tray 49. The mode setting can be performed using the operation portion 302 or the external device 301. Hereinafter, the sheet sending control in the first tray 49 in the mixing prohibition mode will be described, but the same applies to the second tray 71. First, when the power supply of the apparatus is turned on, the stacker control portion 330 obtains position information of the first tray 49 from the detection states of the area detection sensors S11 to S20, and determines whether or not the first tray 49 is in a full load state from job information (a sheet size or the like) stored before the power supply is turned off last time (S101).

In a case where it is determined in S101 that the first tray 49 is in the full load state (Yes in S101), information indicating that the first tray 49 is full is transmitted from the communication portion 321 serving as a notification portion to the communication portion 306 of the image forming apparatus A, and the information indicating that the first tray 49 is full is displayed on the display portion of the operation portion 302 (S102). At this time, the stacker control portion 330 monitors a signal of the second light receiving portion 510b (S103), and in a case where the signal of the second light receiving portion 510b is still the ON signal (No in S103), the displaying of the information indicating that the first tray 49 is full is continued (S102). On the other hand, in a case where the signal of the second light receiving portion 510b becomes the OFF signal (Yes in S103), the processing proceeds to a “sheet presence/absence detection routine” for detecting the presence/absence of a sheet on the first tray 49 (S104). Examples of a case where the signal of the second light receiving portion 510b becomes the OFF signal include a case where a sheet on the first tray 49 is removed by the operator. The “sheet presence/absence detection routine” will be described below. In a case where it is determined in S101 that the first tray 49 is not in the full load state (No in S101), the processing proceeds to S107.

In a case where it is determined in the “sheet presence/absence detection routine” in S104 that there is a sheet on the first tray 49 (Yes in S105), the sheet presence/absence detection routine is continued. In a case where it is determined in S101 that the first tray 49 is in the full load state, the displaying of the information indicating that the first tray 49 is full is also continued. On the other hand, in a case where it is determined in the “sheet presence/absence detection routine” in S104 that there is no sheet on the first tray 49 (No in S105), the displaying of the information indicating that the first tray 49 is full is terminated (S106), and a job is accepted (S107). That is, the full load state is not released unless the sheet is removed from the first tray 49, and a job is not accepted unless the full load state is released. In a case where the information indicating that the first tray 49 is full is not displayed, the processing proceeds from S105 to $107. The operation up to this point is an initialization operation performed from when the power supply is turned on to when a job is accepted. In this state, the first tray 49 is stopped at a predetermined position (sheet presence/absence detection position) described below.

When a job is accepted in S107, the output of the second light receiving portion 510b is checked again (S108). This is to check that no sheet is placed on the first tray 49 after the initialization operation. In a case where it is determined in S108 that there is a sheet on the first tray 49 (Yes in S109), the communication portion 321 serving as the notification portion notifies that there is a sheet on the first tray 49. Specifically, information indicating that there is a sheet on the first tray 49 is transmitted from the communication portion 321 to the communication portion 306 of the image forming apparatus A, and information indicating that there is a sheet on the first tray 49 such as “Please remove the sheet” is displayed on the display portion of the operation portion 302 (S110).

The stacker control portion 330 counts an elapsed time from when the information indicating that there is a sheet on the first tray 49 is displayed on the display portion, and in a case where no job continuation command has been issued within a first predetermined time (No in S111), the stacker control portion 330 continues to display the information indicating that there is a sheet until the first predetermined time elapses (No in S112) (S110). The job continuation command is, for example, a command to continue the job by operating the operation portion or the like even when the user recognizes that there is a sheet on the first tray 49. Therefore, for example, a button or the like for instructing continuation of the job may be displayed on the display portion together with the information “Please remove the sheet”.

In a case where the job continuation command has been issued within the first predetermined time in S111 (Yes in S111), the first tray 49 is moved to the sheet reception position to send a partition sheet onto the sheet stacked on the first tray 49 (S113). The partition sheet is, for example, a sheet of a type different from the sheet stacked on the first tray 49, and is sent onto the uppermost stacked sheet in order to distinguish between the sheet already stacked on the first tray 49 and the sheet to be sent to the first tray 49. The different type of sheet may have a different size or different color. Even in a case where the first predetermined time has elapsed in S112, the partition sheet is sent (S113).

After the partition sheet is sent, a job is executed, and a sheet for the job is sent (S114). In a case where it is determined in the “sheet presence/absence detection routine” in S108 that there is no sheet on the first tray 49 (No in S109), the first tray 49 is moved to the sheet reception position (state in FIG. 11), and a job is executed to send a sheet (S114).

During execution of a job, the stacker control portion 330 monitors the signal of the second light receiving portion 510b, and when a sheet is removed from the first tray 49 on the way, the first tray 49 is lifted to the sheet reception position. In addition, the “sheet presence/absence detection routine” may be executed every time when a sheet is removed from the first tray 49 during a time after one job is completed and before the next job is input, that is, when the signal of the second light receiving portion 510b is switched from the ON signal to the OFF signal.

When the sending of the sheet in S114 is started, the stacker control portion 330 determines whether or not the first tray 49 is in the full load state from the detection states of the area detection sensors S11 to S20 and the job information (the sheet size or the like) (S115). In a case where it is determined that the first tray 49 is in the full load state (Yes in S115), the processing returns to S102. In a case where it is determined in S115 that the first tray 49 is not in the full load state (No in S115), the job is continued, and when the next job is input within a second predetermined time after the end of the job (Yes in S116), the processing returns to S107. In a case where the next job is not input even after the second predetermined time has elapsed (No in S116), the apparatus enters a sleep state (S117), and the control is terminated. The sleep state is a more power-saving state than a standby state in which the input of a job is waited for.

In a case where the mixing prohibition mode is not set, the sheet presence/absence detection routine may be executed only when the first tray 49 is in the full load state to check the presence/absence of a sheet on the first tray 49 after the first tray 49 enters the full load state, the sheet presence/absence detection routine is not executed except when the first tray 49 is in the full load state, and the first tray 49 may be moved to the sheet reception position to execute a job when the job is accepted without performing the processings of S108 to S113. In addition, a mode for accepting the next job in a state in which some sheets are removed without removing all the sheets may be set without executing the sheet presence/absence detection routine when the first tray 49 is in the full load state.

Sheet Presence/Absence Detection Routine

Next, the above-described sheet presence/absence detection routine will be described with reference to FIG. 19. When the second light receiving portion 510b is turned off and the routine is started, the first tray 49 is lifted until the signal of the second light receiving portion 510b is switched from the OFF signal from the ON signal in S201. When the second light receiving portion 510b is turned on, the height position of the first tray 49 is detected from the states of the area detection sensors S11 to S20 (S202). In a case where the height position of the first tray 49 detected in S202 is a second predetermined position sufficiently lower than the above-described predetermined position (also referred to as a first predetermined position) or a position lower than the second predetermined position (Yes in S203), the stacker control portion 330 determines that there is a sheet on the first tray 49 (S204).

That is, in a case where the position of the first tray 49 when the first tray 49 is lifted until the signal of the second light receiving portion 510b is switched from the OFF signal to the ON signal is a position (the second predetermined position or a position lower than the second predetermined position) lower than a position (predetermined height position) lowered by a predetermined amount from the sheet reception position where the sheet is sent from the sending roller pair 42 in a case where there is no sheet on the first tray 49, the stacker control portion 330 determines that there is a sheet on the first tray 49 regardless of the detection of the presence or absence of a sheet by the sheet presence/absence detection mechanism 220 (that is, regardless of the electric signal of the output portion 325), and the communication portion 321 notifies that there is a sheet on the first tray 49.

The second predetermined position is a position where there is a sufficient sheet bundle on the first tray 49 and the upper surface of the uppermost sheet of the sheet bundle is detected by the second light receiving portion 510b. For example, the second predetermined position is a position where the area detection sensor S13 immediately below the area detection sensor S12 that is the home position sensor among the area detection sensors illustrated in FIG. 13 detects the shielding plate 192. In a case where the shielding plate 192 is detected by the area detection sensor S13 or a sensor below the area detection sensor S13, it can be determined that there is a sheet on the first tray 49 at this time point since the first tray 49 is at a sufficiently low position due to the stacking of sheets.

In S203, in a case where the height position of the first tray 49 is not the second predetermined position or a position lower than the second predetermined position, that is, the height position of the first tray 49 is a position higher than the second predetermined position (No in S203), the processing proceeds to S205. In a case where the height position of the first tray 49 is a position higher than the second predetermined position, whether or not there is a sheet on the first tray 49 cannot be determined at this time. Therefore, first, the first tray 49 is lifted by the first predetermined distance (for example, 3 mm) (S205). Then, it is checked whether or not the area detection sensor S12 is turned on (S206). In a case where the area detection sensor (tray HP sensor) S12 is not turned on (No in S206), it can be determined that there is a sheet on the first tray 49, and the processing proceeds to S204.

On the other hand, in a case where the area detection sensor (home position sensor) S12 is turned on in S206 (Yes in S206), the first tray 49 is lifted to the predetermined position (first predetermined position) which is a position where the presence or absence of a sheet is detected by the sheet presence/absence detection mechanism 220 (S207). The position where the area detection sensor S12 is turned on is the home position of the first tray 49, and the first predetermined position is a position lifted from the home position by a second predetermined distance (for example, 8.6 mm). The movement of the first tray 49 by the first predetermined distance and the movement of the first tray 49 by the second predetermined distance can be performed using the encoder 520 and the tray position detection sensor S10.

Once the first tray 49 is moved to the first predetermined position, the sheet presence/absence detection processing is performed (S208). The sheet presence/absence detection processing is processing of determining whether or not the second light receiving portion 510b has received light emitted from the light emitting portion 510d. In a case where the second light receiving portion 510b is turned on (Yes in S209), the moving member 193 is positioned at the second position, so that the detection target portion 193c blocks light emitted from the light emitting portion 510d. Therefore, it can be determined that there is a sheet on the first tray 49, and the processing proceeds to S204.

That is, when detecting the presence or absence of a sheet on the first tray 49, the first tray 49 is lifted until the detection portion 221 transitions from the non-detection state to the detection state. Then, in a case where the position of the first tray 49 at this time is a position within a predetermined amount from the sheet reception position (a lifted position equal to or higher than the second predetermined position that is the predetermined height position), the first tray 49 is moved to the predetermined position, the presence or absence of a sheet on the first tray 49 is detected by the sheet presence/absence detection mechanism 220 (that is, the stacker control portion 330 determines the presence or absence of a sheet on the first tray 49 according to the electric signal of the output portion 325), and in a case where it is detected that there is a sheet on the first tray 49, the communication portion 321 notifies that there is a sheet on the first tray 49. On the other hand, in a case where the second light receiving portion 510b is turned off (No in S209), the moving member 193 is positioned at the first position, so that the detection target portion 193c does not block light emitted from the light emitting portion 510d. Therefore, the stacker control portion 330 determines that there is no sheet on the first tray 49 (S210).

Sheet Presence/Absence Detection Operation

An operation in FIG. 19 described above will be described with reference to FIGS. 20 to 27. Hereinafter, a sheet presence/absence detection operation will be described with a state in which there is no sheet on the first tray 49, a state in which there is one sheet, and a state in which there are about 10 sheets as examples. FIGS. 20 to 27 are views of the upstream end portion side of the first tray 49 in the sheet sending direction when viewed from the front to the back of the apparatus. Therefore, although the second light receiving portion 510b is not illustrated, the position of the second light receiving portion 510b is at the same height as the light emitting portion 510d. Therefore, a state in which the light emitting portion 510d is blocked by any one of the sheet, the first tray 49, and the detection target portion 193c of the moving member 193 indicates a state in which the second light receiving portion 510b is shielded from light (that is, the second light receiving portion 510b is in the ON state).

Operation when There is No Sheet

First, the sheet presence/absence detection operation performed by the sheet presence/absence detection mechanism 220 in a state in which there is no sheet on the first tray 49 will be described with reference to FIGS. 20 to 22. In the sheet presence/absence detection operation, first, the first tray 49 is lifted until the second light receiving portion 510b is turned on (S201 in FIG. 19) as illustrated in FIG. 20. Here, since the height position of the first tray 49 is not the second predetermined position or a position lower than the second predetermined position (No in S203 in FIG. 19), the first tray 49 is lifted by the first predetermined distance as illustrated in FIG. 21 (S205 in FIG. 19). Here, since the area detection sensor S12 is in a state of detecting the shielding plate 192 (that is, the ON state) (Yes in S206 in FIG. 19), the first tray 49 is lifted to the first predetermined position (S207 in FIG. 19) as illustrated in FIG. 22.

Then, the sheet presence/absence detection processing is performed (S208 in FIG. 19). Here, the moving member 193 is positioned at the first position, and the detection target portion 193c does not shield the light emitting portion 510d from light. That is, the second light receiving portion 510b is in the OFF state (No in S209 in FIG. 19). Therefore, the stacker control portion 330 determines that there is no sheet on the first tray 49. The first tray 49 waits for reception of the next job in a state of being stopped at the first predetermined position (sheet presence/absence detection position).

Operation when There is One Sheet

Next, the sheet presence/absence detection operation performed by the sheet presence/absence detection mechanism 220 in a state in which there is one sheet on the first tray 49 will be described with reference to FIGS. 23 to 25. In the sheet presence/absence detection operation, first, the first tray 49 is lifted until the second light receiving portion 510b is turned on (S201 in FIG. 19) as illustrated in FIG. 23. Here, since the height position of the first tray 49 is not the second predetermined position or a position lower than the second predetermined position (No in S203 in FIG. 19), the first tray 49 is lifted by the first predetermined distance as illustrated in FIG. 24 (S205 in FIG. 19). Here, the area detection sensor S12 is in a state of detecting the shielding plate 192 (that is, the ON state) (Yes in S206 in FIG. 19). In this example, a case where there is one sheet on the first tray 49 is illustrated, but for example, a similar state is obtained even when there are about 10 thin sheets.

Since the area detection sensor S12 is turned on, the first tray 49 is lifted to the first predetermined position as illustrated in FIG. 25 (S207 in FIG. 19). Then, the sheet presence/absence detection processing is performed (S208 in FIG. 19). Here, the moving member 193 is positioned at the second position, and the detection target portion 193c shields the light emitting portion 510d from light. That is, the second light receiving portion 510b is in the ON state (Yes in S209 in FIG. 19). Therefore, the stacker control portion 330 determines that there is a sheet on the first tray 49. Similarly, the first tray 49 is stopped at the first predetermined position.

Operation when there are 10 or More Sheets

Next, the sheet presence/absence detection operation performed by the sheet presence/absence detection mechanism 220 in a state in which there are about 10 sheets (for example, plain paper) on the first tray 49 will be described with reference to FIGS. 26 and 27. In the sheet presence/absence detection operation, first, the first tray 49 is lifted until the second light receiving portion 510b is turned on (S201 in FIG. 19) as illustrated in FIG. 26. Here, since the height position of the first tray 49 is not the second predetermined position or a position lower than the second predetermined position (No in S203 in FIG. 19), the first tray 49 is lifted by the first predetermined distance as illustrated in FIG. 27 (S205 in FIG. 19).

Here, the area detection sensor S12 is in a state of not detecting the shielding plate 192 (that is, the OFF state) (No in S206 in FIG. 19). Therefore, the stacker control portion 330 determines that there is a sheet on the first tray 49 and stops lifting of the first tray 49.

According to the present embodiment as described above, it is possible to accurately detect the presence or absence of a sheet on the first tray 49 without arranging an electrical component on the first tray 49 and without requiring a wiring to the outside, and it is possible to prevent a stacking failure or page missing due to a sheet left on the first tray 49. As a result, it is possible to provide a sheet processing apparatus having reliability sufficient to withstand the lifting/lowering operation of the first tray 49 without using a complicated configuration while maintaining the quality of a product.

In the present embodiment, the sheet presence/absence detection mechanism 220 that detects the presence or absence of a sheet on the first tray 49 includes the moving member 193 provided on the first tray 49 and the detection portion 221 provided in the apparatus housing 27. The apparatus housing 27 is provided with the circuit board 500 connected to the detection portion 221 by the wiring 503. Therefore, the wiring connecting the detection portion 221 and the circuit board 500 can be disposed only on an apparatus housing 27 side, and disconnection of the wiring can be suppressed. In addition, the cost required for securing the strength of the wiring or guiding the wiring can be made lower than a case where the wiring is arranged so as to straddle the first tray 49 and the apparatus housing 27. In particular, in the present embodiment, the cost can be further reduced by using the detection portion 221 also as a sensor that detects the upper surface of the sheet. As a result, the presence or absence of a sheet on the first tray 49 can be detected at low cost.

Although the present embodiment describes a positional relationship in which the area detection sensor S12 does not detect the shielding plate 192 of the first tray 49 when the second light receiving portion 510b (upper surface detection sensor) transitions from the OFF state to the ON state by lifting the first tray 49 in a state in which there is no sheet on the first tray 49, the present invention is not limited thereto. For example, an arrangement relationship in which the area detection sensor S12 can detect the shielding plate 192 before the second light receiving portion 510b transitions from the OFF state to the ON state by lifting the first tray 49 may be established. That is, the first tray 49 may be moved to the sheet presence/absence detection position to detect the presence/absence of a sheet on the first tray 49 in a case where it is detected that the movement amount of the first tray 49 from when the area detection sensor S12 detects the shielding plate 192 to when the second light receiving portion 510b is turned on is equal to or smaller than a predetermined amount. In any case, the height position of the first tray 49 when the second light receiving portion 510b transitions from the OFF state to the ON state by lifting the first tray 49 is detected, and in a case where the height position is a position lower than a predetermined height, it is clearly determined that there is a sheet on the first tray 49, and in a case where the first tray 49 is at a lifted position equal to or higher than the predetermined height, it cannot be determined whether or not there is a sheet on the first tray 49. Therefore, the presence or absence of a sheet is reliably detected using the sheet presence/absence detection mechanism 220.

Second Embodiment

A second embodiment will be described with reference to FIGS. 28 and 29. In the present embodiment, when a sheet presence/absence detection operation is performed, a paddle 275 is lowered to press a sheet against a first tray 49. Since other configurations and operations are similar to those of the first embodiment described above, the same reference numerals are given to similar configurations, a description and illustration thereof are omitted or simplified, and hereinafter, differences from the first embodiment will be mainly described.

In a case where the sheet stacked on the first tray 49 is a sheet having a small grammage such as a thin sheet, there is a possibility that a moving member 193 cannot be sufficiently moved from a first position to a second position only by the weight of the sheet. In this case, it may be detected that there is no sheet even though there is a sheet on the first tray 49. Therefore, in the present embodiment, as illustrated in FIG. 28, the paddle 275 serving as a conveyance portion is positioned at a conveyance position to press the sheet on the first tray 49 at the time of the sheet presence/absence detection operation (that is, when a stacker control portion 330 determines the presence or absence of a sheet on the first tray 49 according to an electric signal output from an output portion 325).

Here, a contact portion 193a of the moving member 193 protrudes upward at the center of the first tray 49 in a width direction. Meanwhile, a pair of paddles 275 are provided while being separated from each other in the width direction as illustrated in FIG. 5 described above, and the pair of paddles 275 are disposed so as to be separated from the center of the first tray 49 in the width direction. Therefore, as illustrated in FIG. 29, even when the paddle 275 is positioned at the conveyance position in a state in which there is no sheet on the first tray 49, the paddle 275 does not interfere with the contact portion 193a. Therefore, even when the paddle 275 is moved from a retraction position to the conveyance position in a state in which there is no sheet on the first tray 49 at the time of the sheet presence/absence detection operation, the paddle 275 does not move the moving member 193, so that the presence of a sheet is not detected when there is no sheet.

As described above, in the present embodiment, it is possible to more reliably detect the presence or absence of a sheet on the first tray 49 by moving the paddle 275 to the conveyance position at the time of the sheet presence/absence detection operation. Such an operation can also be performed using a width direction alignment portion 272 illustrated in FIG. 5 described above. In this case, a pair of alignment members 273a and 273b are lowered in a state of being closer to the center of the sheet in the width direction than when performing sheet alignment in the width direction, that is, at a position where the pair of alignment members 273a and 273b can come into contact with the sheet on the first tray 49. At this time, the alignment members 273a and 273b are stopped at a position higher than a position where an operation of aligning the sheets in the width direction is performed. This is because the sheet is damaged when the alignment members 273a and 273b are lowered to a similar position even in the case of detecting the presence or absence of a sheet since the alignment members 273a and 273b are lowered until the alignment members 273a and 273b partially enter a recess 49b of the first tray 49 at the time of the operation of aligning the sheet in the width direction.

Third Embodiment

A third embodiment will be described with reference to FIGS. 30 to 32. In the first embodiment described above, the detection portion 221 is a transmissive sensor. On the other hand, in the present embodiment, a detection portion 221A is a reflective sensor. Since other configurations and operations are similar to those of the first embodiment described above, the same reference numerals are given to similar configurations, a description and illustration thereof are omitted or simplified, and hereinafter, differences from the first embodiment will be mainly described.

FIG. 30 illustrates a state in which a lower cover of a first tray 49 is removed. A sheet presence/absence detection mechanism 220A according to the present embodiment includes a moving member 222 serving as the displacement portion and a detection portion 221A. The detection portion 221A is provided on an abutment member 271 side of an apparatus housing 27 further upstream of an upstream end portion of the first tray 49 in a sheet sending direction. The abutment member 271 is formed with an abutment surface 271a against which a trailing edge of a sheet abuts, and a groove portion 271b recessed from the abutment surface 271a. The detection portion 221A is disposed in the groove portion 271b so as not to protrude from the abutment surface 271a. The detection portion 221A includes a light emitting portion and a light receiving portion, and in a case where light emitted from the light emitting portion is reflected by a detection target portion 225a described below, the light receiving portion can receive the light. Also in the present embodiment, there is provided an output portion that outputs an electric signal according to a light receiving state of the light receiving portion of the detection portion 221A as described with reference to FIG. 3.

The moving member 222 includes a first member 223 swingably supported by the first tray 49 and a second member 225 connected to the first member 223 by a connection shaft 224. The first member 223 and the second member 225 are swingably supported by the first tray 49 via the connection shaft 224, and the second member 225 is swingable about the connection shaft 224 by interlocking with the swinging of the first member 223. The reason why the second member 225 is provided is that the detection portion 221A is disposed in the groove portion 271b of the abutment member 271 as described above. As the second member 225 is provided, the detection target portion 225a which is a part of the moving member 222 can face the detection portion 221A at that position.

In the first member 223, a contact portion 223a that can come into contact with a sheet is provided at a distal end portion, and a first connection portion 223b that is connected to the connection shaft 224 is provided at a proximal end portion. In the second member 225, the detection target portion 225a facing the detection portion 221A is provided at a distal end portion, and a second connection portion 225b connected to the connection shaft 224 is provided at a proximal end portion.

Similarly to the contact portion 193a of the first embodiment, the contact portion 223a of the first member 223 can protrude upward from a stacking surface 49a and retract downward from the stacking surface 49a via a through hole 49d provided in the first tray 49. In a case where there is no sheet on the first tray 49 and the contact portion 223a is at a first position protruding upward from the stacking surface 49a, the detection target portion 225a of the second member 225 faces the detection portion 221A as illustrated in FIG. 31. In this state, the detection portion 221A is turned on.

On the other hand, in a case where there is a sheet S1 on the first tray 49 and the contact portion 223a is positioned at a second position lower than the first position due to contact with the sheet, the detection target portion 225a is positioned at a position deviated from the position facing the detection portion 221A as illustrated in FIG. 32. In this state, the detection portion 221A is turned off. That is, in the present embodiment, the detection portion 221A is turned on when there is no sheet on the first tray 49, and the detection portion 221A is turned off when there is a sheet.

Also in the present embodiment as described above, similarly to the first embodiment, a sheet presence/absence detection operation is performed in a state in which the first tray 49 is at a predetermined position. In a case where the detection portion 221A is turned on, it is determined that there is no sheet on the first tray 49, and in a case where the detection portion 221A is turned off, it is determined that there is a sheet on the first tray 49.

In the present embodiment, the detection portion 221A is not also used as an upper surface detection portion 502 that detects the first tray 49 or a sheet stacked on the first tray 49. Therefore, the presence or absence of a sheet on the first tray 49 can be detected by moving the first tray 49 to a predetermined position without executing the routine as illustrated in FIG. 19. At this time, a movement amount of the first tray 49 at the time of detecting the presence or absence of a sheet can be reduced by setting the predetermined position to the same position as a sheet reception position (or a position close to the sheet reception position).

In the present embodiment, the detection target portion 225a is positioned at the position facing the detection portion 221A in a case where there is a sheet on the first tray 49. However, the detection target portion 225a may also be set to be positioned at a position facing the detection portion 221A in a case where there is no sheet. In this case, a relationship between an ON state and an OFF state of the detection portion 221A and determination of the presence or absence of a sheet is opposite to the above. Therefore, also in the present embodiment, it is sufficient if the detection target portion 225a which is a part of the moving member 222 reflects light emitted from the light emitting portion and cause the light receiving portion to receive the light in a case where the moving member 222 is at one of the first position and the second position.

Furthermore, in the present embodiment, as long as the position of the detection portion 221A can be the same as that of the first member 223 in the width direction, the second member 225 may be omitted, and a detection target portion may be provided in the first member 223. Furthermore, also in the present embodiment, a paddle 275 may be positioned at a conveyance position at the time of the sheet presence/absence detection operation as in the second embodiment.

Fourth Embodiment

A fourth embodiment will be described with reference to FIGS. 33 and 34. In the first embodiment described above, the movement of the moving member 193 is directly detected by the detection portion 221. On the other hand, in the present embodiment, movement of a moving member 193A is indirectly detected by a detection portion 221B. Since other configurations and operations are similar to those of the first embodiment described above, the same reference numerals are given to similar configurations, a description and illustration thereof are omitted or simplified, and hereinafter, differences from the first embodiment will be mainly described.

A sheet presence/absence detection mechanism 220B according to the present embodiment includes the moving member 193A and the detection portion 221B. Similarly to the first embodiment, the moving member 193A serving as the displacement portion and a first displacement portion is swingably supported by a first tray 49 via a swing support portion 193b. In addition, a contact portion 193a provided on one side of the swing support portion 193b can protrude upward from a stacking surface 49a and retract downward from the stacking surface 49a via a through hole 49d provided in the first tray 49. However, an abutting portion 193e is provided on the other side of the swing support portion 193b instead of a detection target portion 193c.

The detection portion 221B is provided in an apparatus housing 27 of a processing unit 200, and includes a contact moving member 230 serving as a second displacement portion and a moving member detection portion 231. In a case where the first tray 49 is at a predetermined position and the moving member 193A is at one of a first position and a second position (that is, in any one of a case where there is no sheet and a case where there is a sheet on the first tray 49), the contact moving member 230 comes into contact with the abutting portion 193e which is a part of the moving member 193A and is displaced according to the displacement of the moving member 193A. The moving member detection portion 231 is a photointerrupter in which a light emitting portion and a light receiving portion are disposed to face each other with a gap therebetween, and the contact moving member (flag) 230 can pass through the gap. The movement of the contact moving member 230 can be detected using the light emitting portion and the light receiving portion. Also in the present embodiment, there is provided an output portion that outputs an electric signal according to a light receiving state of the light receiving portion of the moving member detection portion 231 as described with reference to FIG. 3. The output portion outputs an electric signal according to the displacement of the contact moving member 230.

In the present embodiment, in a case where there is no sheet on the first tray 49 and the moving member 193A is at the first position, the abutting portion 193e of the moving member 193 does not abut on the contact moving member 230 as illustrated in FIG. 33. As a result, the detection portion 221B enters an OFF state in which the contact moving member 230 is not detected by the moving member detection portion 231.

On the other hand, in a case where there is a sheet S1 on the first tray 49 and the moving member 193A is at the second position, the abutting portion 193e of the moving member 193 comes into contact with the contact moving member 230 as illustrated in FIG. 34. As a result, the detection portion 221B enters an ON state in which the contact moving member 230 is detected by the moving member detection portion 231.

Also in the present embodiment as described above, similarly to the first embodiment, a sheet presence/absence detection operation is performed in a state in which the first tray 49 is at a predetermined position. In a case where the detection portion 221B is turned on, it is determined that there is a sheet on the first tray 49, and in a case where the detection portion 221B is turned off, it is determined that there is no sheet on the first tray 49.

In the present embodiment, the detection portion 221B is not also used as an upper surface detection portion 502 that detects the first tray 49 or a sheet stacked on the first tray 49. Therefore, the presence or absence of a sheet on the first tray 49 can be detected by moving the first tray 49 to a predetermined position without executing the routine as illustrated in FIG. 19. Also in the present embodiment, a paddle 275 may be positioned at a conveyance position at the time of the sheet presence/absence detection operation as in the second embodiment.

Fifth Embodiment

A fifth embodiment will be described with reference to FIGS. 35A to 36B. In the first embodiment described above, the moving member 193 is provided so as to partially protrude upstream of the first tray 49 in the sheet sending direction, and the light emitting portion 510d and the second light receiving portion 510b included in the detection portion 221 are disposed on both sides of the stacking surface 49a in the width direction so as to sandwich a part of the moving member 193. On the other hand, in the present embodiment, a flag 250 serving as an interlocking portion that interlocks with a moving member 240 protrudes from one end portion of a first tray 49 in a width direction, and a light emitting portion 511a and a light receiving portion 511b included in a detection portion 221C are disposed on both sides in a substantially vertical direction so as to sandwich the flag 250. Since other configurations and operations are similar to those of the first embodiment described above, the same reference numerals are given to similar configurations, a description and illustration thereof are omitted or simplified, and hereinafter, differences from the first embodiment will be mainly described.

FIGS. 35A and 35B illustrate a state in which there is no sheet on the first tray 49, and FIGS. 36A and 36B illustrate a state in which there is a sheet on the first tray 49. FIGS. 35A and 36A are perspective views schematically illustrating a sheet presence/absence detection mechanism 220C and the detection portion 221C in an extracted manner, and FIGS. 35B and 36B are plan views of the first tray 49 when viewed from above.

The detection portion 221C includes the light emitting portion 511a provided in a processing unit 200 (see FIG. 2) and the light receiving portion 511b capable of receiving light emitted from the light emitting portion 511a and provided in the processing unit 200. Also in the present embodiment, an output portion 325 (see FIG. 3) outputs an electric signal according to a light receiving state of the light receiving portion 511b, and a stacker control portion 330 determines the presence or absence of a sheet on the first tray 49 according to the electric signal output from the output portion 325.

In the present embodiment, the light emitting portion 511a and the light receiving portion 511b are disposed at positions deviated from a lifting/lowering range of the first tray 49 in the substantially vertical direction and are disposed so as to sandwich the flag 250 described below. That is, the light emitting portion 511a and the light receiving portion 511b are disposed at positions not overlapping the first tray 49 when the first tray 49 is viewed from above and are disposed more outward than one end portion of the first tray 49 in the width direction. One of the light emitting portion 511a and the light receiving portion 511b (the light emitting portion 511a in the present embodiment) is disposed above a position where the first tray 49 can be lifted the most, and the other (the light receiving portion 511b in the present embodiment) is disposed below a position where the first tray 49 can be lowered the most. The substantially vertical direction includes a complete vertical direction, but may be slightly inclined with respect to the vertical direction. That is, the light emitting portion 511a and the light receiving portion 511b may be arranged at an angle with respect to the complete vertical direction as long as light from emitted the light emitting portion 511a can be blocked when the flag 250 is moved to a light blocking position regardless of the position of the first tray 49 in the lifting/lowering range.

As illustrated in FIGS. 35A and 36A, the moving member 240 serving as the displacement portion is swingably supported by the first tray 49, and is connected to the flag 250 by a connection shaft 241. In the moving member 240, a contact portion 242 that can come into contact with a sheet is provided at a distal end portion, and a first connection portion 243 connected to the connection shaft 241 is provided at a proximal end portion. Similarly to the contact portion 193a of the first embodiment, the contact portion 242 of the moving member 240 can protrude upward from a stacking surface 49a and retract downward from the stacking surface 49a via a through hole 49d provided in the first tray 49.

The flag 250 serving as the interlocking portion is swingable about the connection shaft 241 by interlocking with the swinging of the moving member 240. That is, as illustrated in FIGS. 35B and 36B, the flag 250 is provided on the first tray 49 so as to protrude from one end portion of the first tray 49 in the width direction, and interlocks with the displacement of the moving member 240. The flag 250 is provided with a detection target portion 252 so as to protrude in the width direction from a second connection portion 251 connected to the connection shaft 241. The detection target portion 252 is movable to a retraction position (FIGS. 35A and 35B) retracting from a path (optical path 511C) of light emitted from the light emitting portion 511a toward the light receiving portion 511b and a shielding position (FIGS. 36A and 36B) that shields the optical path 511C.

That is, as illustrated in FIGS. 35A and 35B, the detection target portion 252 retracts from the optical path 511C, and light emitted from the light emitting portion 511a is received by the light receiving portion 511b in a state in which there is no sheet on the first tray 49. On the other hand, as illustrated in FIGS. 36A and 36B, when a sheet S is stacked on the first tray 49, the contact portion 242 of the moving member 240 comes into contact with the sheet, and the moving member 240 swings, the flag 250 rotates by interlocking with the swinging of the moving member 240 via the first connection portion 243, the connection shaft 241, and the second connection portion 251. Then, the detection target portion 252 is positioned at the shielding position, and light of the light emitting portion 511a is blocked.

The stacker control portion 330 determines that there is a sheet on the first tray 49 in a case where the light receiving portion 511b is shielded from light, and determines that there is no sheet on the first tray 49 in a case where the light receiving portion 511b receives light. In the present embodiment, the light emitting portion 511a and the light receiving portion 511b are disposed on an outer side of the first tray 49 in the width direction, and the flag 250 interlocking with the moving member 240 is disposed so as to protrude to the outer side of the first tray 49 in the width direction. As a result, the presence or absence of a sheet on the first tray 49 can be detected regardless of the position of the first tray 49 in the lifting/lowering direction.

Other Embodiments

In each of the above-described embodiments, the configuration in which the binding processing is performed as the predetermined processing performed by the processing unit has been described. However, the predetermined processing is not limited to the binding processing, and may be folding processing, shift processing, punching processing, creasing, laminating processing, or the like. FIG. 37 illustrates, as a first example, a configuration in which a processing unit 200A of a sheet processing apparatus B performs only the folding processing on a sheet. That is, the processing unit 200A includes a sheet folding device 410 serving as the processing portion. The sheet folding device 410 has a configuration similar to that described in JP 2020-45244 A, for example.

The sheet folding device 410 will be briefly described. The sheet folding device 410 is disposed below a straight path 28, and performs the folding processing on a sheet sent to a conveyance path 411 branching downward from the straight path 28. The sheet folding device 410 includes a first roller 412, a second roller 413, and a third roller 414, and conveys a sheet in a state of being appropriately curved to a nip portion between the first roller 412 and the second roller 413 and a nip portion between the second roller 413 and the third roller 414 to perform the folding processing such as bi-folding or tri-folding on the sheet. Then, the sheet subjected to the folding processing is sent from a sending roller pair 42 serving as the sending portion to a stacking tray 416 serving as the stacking portion via a conveyance path 415. Detection of the presence or absence of a sheet on the stacking tray 416 and control of a lifting/lowering operation of the stacking tray 416 are similar to those in the above-described embodiments.

FIG. 38 illustrates, as a second example, a configuration in which a processing unit 200B of a sheet processing apparatus B performs only the shift processing of shifting a sheet in a width direction. That is, the processing unit 200B includes a shift device 400 serving as the processing portion. The shift device 400 has a configuration similar to a known configuration according to a related art, but in the illustrated example, a roller pair 401 that conveys a sheet on a straight path 28 is movable in the width direction while nipping the sheet. The sheet moved (subjected to the shift processing) in the width direction by the roller pair 401 is sent from the roller pair 401 also functioning as the sending portion to a stacking tray 402 serving as the stacking portion. Detection of the presence or absence of a sheet on the stacking tray 402 and control of a lifting/lowering operation of the stacking tray 402 are similar to those in the above-described embodiments. The shift processing may be performed by moving an alignment plate abutting on an end portion of the sheet in the width direction, for example, instead of shifting the roller pair described above.

In each of the above-described embodiments, an example has been described in which the determination of the presence or absence of a sheet on the first tray 49 (or the second tray 71) is performed by the stacker control portion 330 (CPU 331) of the sheet processing apparatus B. However, the control portion 310 (CPU 311) of the image forming apparatus A may determine the presence or absence of a sheet on the first tray 49 (or the second tray 71) by transmitting information from the detection portion 221 (221A and 221B) to the image forming apparatus A.

In this case, the interface portion 326 provided in the processing unit 200 corresponds to the reception portion and a first reception portion that receive an electric signal output from the output portion 325. In addition, the communication portion 321 provided in the processing unit 200 corresponds to a transmission portion that transmits an electric signal received by the interface portion 326 to the image forming apparatus A. Furthermore, the communication portion 306 of the image forming apparatus A corresponds to a second reception portion that receives an electric signal output from the output portion 325 transmitted from the communication portion 321. The control portion 310 of the image forming apparatus A corresponds to the determination portion that determines the presence or absence of a sheet on the first tray 49 (or the second tray 71) according to an electric signal received from the communication portion 306 (see FIG. 3).

Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2023-074572, filed on Apr. 28, 2023, and Japanese Patent Application No. 2024-047347, filed on Mar. 22, 2024, which are hereby incorporated by reference herein in their entirety.

Number	Date	Country	Kind
2023-074572	Apr 2023	JP	national
2024-047347	Mar 2024	JP	national

SHEET PROCESSING APPARATUS AND IMAGE FORMING SYSTEM

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