EP4671175A1

EP4671175A1 - Leaf feeder device for detecting a quantity of leaves dispensed from a stack of leaves without providing a dedicated sensor, imaging device and detection method

Info

Publication number: EP4671175A1
Application number: EP25183868.6A
Authority: EP
Inventors: Sueaki Okamoto; Yuta Kitabayashi; Yuji Toyota; Yuji Kamiyama
Original assignee: Kyocera Document Solutions Inc
Current assignee: Kyocera Document Solutions Inc
Priority date: 2024-06-25
Filing date: 2025-06-18
Publication date: 2025-12-31
Also published as: US20250388421A1; JP2026003930A

Abstract

A sheet conveying device includes a sheet supply portion (28), a detection portion (25), and an acquisition processing portion (44). The sheet supply portion (28) supplies an uppermost sheet (SH1) in a stack of sheets (SB1) lifted by a lift portion (31). The detection portion (25) detects the sheet (SH1) supplied by the sheet supply portion (28). The acquisition processing portion (44) acquires a pay-out amount of the sheet (SH1) from the stack of sheets (SB1) based on an elapsed time from a start of supply of the sheet (SH1) by the sheet supply portion (28) to a time when the sheet (SH1) is detected by the detection portion (25), that is measured at a timing at which the stack of sheets (SB1) is lifted by the lift portion (31), and an elapsed time from the start of supply of the sheet (SH1) by the sheet supply portion (28) to the time when the sheet (SH1) is detected by the detection portion (25), that is measured after the timing.

Description

BACKGROUND

The present disclosure relates to a sheet conveying device, an image forming apparatus, and an acquisition method.
An image forming apparatus such as a multifunction peripheral includes a sheet conveying device which conveys a sheet on which an image is to be formed. For example, the sheet conveying device includes a lift portion and a sheet supply portion. The lift portion lifts a stack of sheets. The sheet supply portion includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies the sheet that comes into contact with the conveying member to a conveying path.
In the sheet conveying device, the sheet below the sheet to be conveyed by the conveying member may be pulled by the sheet to be conveyed so as to be fed out from the stack of sheets. In contrast, a sheet conveying device including an image sensor capable of detecting a protrusion amount of the sheet from a separation nip portion is known as the related art. By changing an arrangement position of the image sensor in this sheet conveying device, it is possible to use the image sensor to acquire a pay-out amount of the sheet from the stack of sheets.

SUMMARY

A sheet conveying device according to an aspect of the present disclosure includes a lift portion, a sheet supply portion, a detection portion, a first measurement processing portion, a second measurement processing portion, and an acquisition processing portion. The lift portion lifts a stack of sheets. The sheet supply portion includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies a sheet that comes into contact with the conveying member to a conveying path. The detection portion detects the sheet supplied by the sheet supply portion on the conveying path. The first measurement processing portion measures, when the stack of sheets is lifted by the lift portion, an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion. The second measurement processing portion measures, after the measurement by the first measurement processing portion, an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion. The acquisition processing portion acquires, based on a measurement result obtained by the first measurement processing portion and a measurement result obtained by the second measurement processing portion, a pay-out amount of an acquisition target sheet from the stack of sheets at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement by the second measurement processing portion.
An image forming apparatus according to another aspect of the present disclosure includes the sheet conveying device and an image forming portion. The image forming portion forms an image on the sheet conveyed by the sheet conveying device.
An acquisition method according to another aspect of the present disclosure is executed in a sheet conveying device including a lift portion which lifts a stack of sheets, a sheet supply portion which includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies a sheet that comes into contact with the conveying member to a conveying path, and a detection portion which detects the sheet supplied by the sheet supply portion on the conveying path, and includes a first measurement step, a second measurement step, and an acquisition step. The first measurement step includes measuring, when the stack of sheets is lifted by the lift portion, an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion. The second measurement step includes measuring, after the measurement in the first measurement step, an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion. The acquisition step includes acquiring, based on a measurement result obtained in the first measurement step and a measurement result obtained in the second measurement step, a pay-out amount of an acquisition target sheet from the stack of sheets at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement in the second measurement step.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description with reference where appropriate to the accompanying drawings. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a diagram showing an outer appearance of an image forming apparatus according to an embodiment of the present disclosure;
Fig. 2 is a diagram showing an internal configuration of the image forming apparatus according to the embodiment of the present disclosure;
Fig. 3 is a block diagram showing a system configuration of the image forming apparatus according to the embodiment of the present disclosure;
Fig. 4 is a diagram showing a configuration of a sheet supply portion in the image forming apparatus according to the embodiment of the present disclosure;
Fig. 5 is a flowchart showing an example of reset processing executed in the image forming apparatus according to the embodiment of the present disclosure;
Fig. 6 is a flowchart showing an example of sheet feed processing executed in the image forming apparatus according to the embodiment of the present disclosure; and
Fig. 7 is a diagram showing the configuration of the sheet supply portion in the image forming apparatus according to the embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present disclosure will be described with reference to the attached drawings. It is noted that the following embodiment is an example of embodying the present disclosure and does not limit the technical scope of the present disclosure.

[Configuration of image forming apparatus 100]

First, a configuration of an image forming apparatus 100 according to an embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 4. Herein, Fig. 1 is a perspective view showing an outer appearance of the image forming apparatus 100. Further, Fig. 2 is a cross-sectional view showing an internal configuration of the image forming apparatus 100. Furthermore, Fig. 4 is an enlarged view of a sheet supply portion 28 shown in Fig. 2.
It is noted that for convenience of descriptions, a vertical direction in a state where the image forming apparatus 100 is installed in a usable state (a state shown in Fig. 1) is defined as an up-down direction D1. In addition, a front-rear direction D2 is defined with a surface of the image forming apparatus 100 on a near left side of a sheet surface shown in Fig. 1 being a front surface (front side). In addition, a left-right direction D3 is defined using the front surface of the image forming apparatus 100 in the installed state as a reference.
The image forming apparatus 100 is a multifunction peripheral having a plurality of functions such as a scanning function, a printing function, a facsimile function, and a copying function. It is noted that the present disclosure may also be applied to image forming apparatuses such as a printer, a facsimile apparatus, and a copying machine.
As shown in Fig. 3, the image forming apparatus 100 includes an ADF (Auto Document Feeder) 1, an image reading portion 2, an image forming portion 3, a sheet feed portion 4, an operation display portion 5, a storage portion 6, and a control portion 7.
The image forming portion 3, the sheet feed portion 4, the storage portion 6, and the control portion 7 are housed in a housing 100A (see Fig. 1 and Fig. 2) of the image forming apparatus 100. The housing 100A is formed in a substantially rectangular parallelepiped shape. The ADF 1 and the image reading portion 2 are provided on an upper side of the housing 100A (see Fig. 1 and Fig. 2). The operation display portion 5 is provided on a front side of the housing 100A (see Fig. 1).
The ADF 1 conveys a document sheet from which an image is to be read by the image reading portion 2. The ADF 1 includes a document sheet setting portion, a plurality of conveying rollers, a document sheet holder, and a sheet discharge portion.
The image reading portion 2 reads an image of a document sheet. That is, the image reading portion 2 realizes the scanning function. The image reading portion 2 includes a document sheet table, a light source, a plurality of mirrors, an optical lens, and a CCD (Charge Coupled Device).
The image forming portion 3 forms an image that is based on image data on a sheet SH1 (see Fig. 2) supplied from the sheet feed portion 4. That is, the image forming portion 3 realizes the printing function. Specifically, the image forming portion 3 forms an image using electrophotography. The image forming portion 3 includes a photoconductor drum, a charging device, a laser scanning unit (LSU), a developing device, a transfer device, a cleaning device, and a fixing device.
The operation display portion 5 is a user interface of the image forming apparatus 100. The operation display portion 5 includes a display portion and an operation portion. The display portion displays various types of information in response to control instructions from the control portion 7. For example, the display portion is a flat panel display such as a liquid crystal display. The operation portion is used to input various types of information to the control portion 7 according to user operations. For example, the operation portion includes an operation key and a touch panel.
The storage portion 6 is a nonvolatile storage device. For example, the storage portion 6 is a nonvolatile memory such as a flash memory.
The control portion 7 collectively controls the image forming apparatus 100. As shown in Fig. 3, the control portion 7 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 is a processor that executes various types of arithmetic processing. The ROM 12 is a nonvolatile storage device in which information such as control programs for causing the CPU 11 to execute various types of processing is stored in advance. The RAM 13 is a volatile or nonvolatile storage device that is used as a temporary storage memory (working area) for the various types of processing to be executed by the CPU 11. In the control portion 7, the CPU 11 executes the various control programs stored in advance in the ROM 12. Thus, the control portion 7 collectively controls the image forming apparatus 100. It is noted that the control portion 7 may be constituted of an electronic circuit such as an integrated circuit (ASIC). Alternatively, the control portion 7 may be a control portion provided separately from a main control portion that collectively controls the image forming apparatus 100.
The sheet feed portion 4 supplies a sheet SH1 (see Fig. 2) to the image forming portion 3.
As shown in Fig. 2 and Fig. 3, the sheet feed portion 4 includes a sheet feed cassette 21, a pickup roller 22, a sheet feed roller 23, a separation roller 24, a sheet sensor 25, a drawing sensor 26, and a conveying path 27.
A stack of sheets SB1 (see Fig. 2) is placed in the sheet feed cassette 21. For example, the stack of sheets SB1 including the sheets SH1 such as paper, coated paper, postcards, envelopes, and OHP sheets is placed in the sheet feed cassette 21. As shown in Fig. 1 and Fig. 2, the sheet feed cassette 21 is provided at a bottom portion of the housing 100A. In addition, the sheet feed cassette 21 is provided so as to be capable of being drawn out from the housing 100A in a drawing direction D4 (see Fig. 1) along the front-rear direction D2. The sheet feed cassette 21 stores the stack of sheets SB1. The sheet feed cassette 21 is detachably provided in the housing 100A. The sheet feed cassette 21 is an example of a sheet storing portion according to the present disclosure.
As shown in Fig. 2, the sheet feed cassette 21 includes a lift plate 31, a lifting and lowering mechanism 32, an end cursor 33, and a pair of side cursors 34.
The lift plate 31 lifts up the stack of sheets SB1 (see Fig. 2) placed in the sheet feed cassette 21. The lift plate 31 is a flat plate-like member provided at the bottom portion of the sheet feed cassette 21. The stack of sheets SB1 is placed on an upper surface of the lift plate 31. The lift plate 31 is provided to be rotatable about a rotation shaft 31A (see Fig. 2) extending in the front-rear direction D2. Specifically, a right end portion of the lift plate 31 is supported rotatably about the rotation shaft 31A. The lift plate 31 is an example of a lift portion according to the present disclosure.
The lifting and lowering mechanism 32 lifts and lowers the lift plate 31. As shown in Fig. 2, the lifting and lowering mechanism 32 includes a rotation shaft 32A and a push-up plate 32B. The rotation shaft 32A extends in the front-rear direction D2. The push-up plate 32B is provided to extend from the rotation shaft 32A toward a direction orthogonal to the extension direction of the rotation shaft 32A. The push-up plate 32B is formed in a flat plate shape that is elongated in the front-rear direction D2. The rotation shaft 32A and the push-up plate 32B are provided below the lift plate 31.
A rear end portion of the rotation shaft 32A is coupled to a motor (not shown) provided outside the sheet feed cassette 21 via a joint portion (not shown) provided outside the sheet feed cassette 21. Upon receiving a rotational driving force supplied from the motor via the joint portion, the rotation shaft 32A and the push-up plate 32B rotate in a second rotation direction D7 shown in Fig. 4. When the rotation shaft 32A and the push-up plate 32B rotate in the second rotation direction D7, the lift plate 31 is pushed up by the push-up plate 32B to thus rotate in a first rotation direction D6 (see Fig. 4) shown in Fig. 4. Thus, the stack of sheets SB1 placed on the upper surface of the lift plate 31 is lifted upwardly.
The joint portion is restricted from rotating in a direction opposite to the second rotation direction D7. For example, the joint portion includes a ratchet mechanism that restricts the joint portion from rotating in the direction opposite to the second rotation direction D7. By restricting the joint portion from rotating in the direction opposite to the second rotation direction D7, the rotation of the rotation shaft 32A engaged with the joint portion in the direction opposite to the second rotation direction D7 is also restricted. This restricts lowering of the lift plate 31 by its own weight.
When the sheet feed cassette 21 is drawn out from the housing 100A in the drawing direction D4, the engagement between the rotation shaft 32A and the joint portion is released. Thus, the restriction of the rotation of the rotation shaft 32A and the push-up plate 32B in the direction opposite to the second rotation direction D7 by the joint portion is released, and the lift plate 31 is lowered by its own weight.
The end cursor 33 is provided so as to be movable along a sheet conveying direction D5 shown in Fig. 4. The end cursor 33 causes the stack of sheets SB1 placed in the sheet feed cassette 21 to abut against a wall surface 21A (see Fig. 4) of the sheet feed cassette 21 on a downstream side of the sheet conveying direction D5, to adjust a position of the stack of sheets SB1 in the sheet conveying direction D5. The pair of side cursors 34 are provided to interlock with each other so as to approach or move away from each other along a width direction of the sheet SH1 orthogonal to the sheet conveying direction D5. The pair of side cursors 34 sandwich and hold the stack of sheets SB1 placed in the sheet feed cassette 21 to adjust the position of the sheets SH1 in the width direction.
As shown in Fig. 2 and Fig. 4, the pickup roller 22 is provided above the lift plate 31. The pickup roller 22 rotates while being in contact with the upper surface of the stack of sheets SB1 lifted by the lift plate 31, thereby conveying an uppermost sheet SH1 (see Fig. 2) in the stack of sheets SB1 to a separation portion 28A (see Fig. 4). Herein, the separation portion 28A is a nip portion formed between the sheet feed roller 23 and the separation roller 24. The pickup roller 22 conveys the sheet SH1 in the sheet conveying direction D5 (see Fig. 4). The sheet conveying direction D5 is a direction orthogonal to the front-rear direction D2. The pickup roller 22 is an example of a conveying member according to the present disclosure.
Specifically, the pickup roller 22 is provided to be rotatable about a shaft extending in the front-rear direction D2. The pickup roller 22 rotates by receiving a rotational driving force supplied from a motor (not shown) while being in contact with the upper surface of the sheet SH1. Thus, the pickup roller 22 applies a conveying force in the sheet conveying direction D5 to the sheet SH1 in contact with the pickup roller 22.
The pickup roller 22, the sheet feed roller 23, and the separation roller 24 constitute the sheet supply portion 28 (see Fig. 2 and Fig. 4) that supplies the sheet SH1 in contact with the pickup roller 22 to the conveying path 27 (see Fig. 2). The conveying path 27 is a movement path of the sheet SH1 that is provided from the sheet supply portion 28 to the image forming portion 3.
As shown in Fig. 2 and Fig. 4, the sheet feed roller 23 is provided more on the downstream side of the sheet conveying direction D5 than the pickup roller 22. The sheet feed roller 23 comes into contact with the upper surface of the sheet SH1 (see Fig. 2) conveyed by the pickup roller 22 and conveys the sheet SH1 beyond a detection position of the sheet SH1 by the sheet sensor 25 (see Fig. 2). The sheet feed roller 23 conveys the sheet SH1 in the sheet conveying direction D5.
Specifically, the sheet feed roller 23 is provided to be rotatable about a shaft extending in the front-rear direction D2. The sheet feed roller 23 rotates by receiving a rotational driving force supplied from a motor (not shown) while being in contact with the upper surface of the sheet SH1. Thus, the sheet feed roller 23 applies a conveying force in the sheet conveying direction D5 to the sheet SH1 in contact with the sheet feed roller 23.
As shown in Fig. 2 and Fig. 4, the separation roller 24 is provided below the sheet feed roller 23 while opposing the sheet feed roller 23. The separation roller 24 forms the separation portion 28A (see Fig. 4) with the sheet feed roller 23. The separation portion 28A separates, from a sheet SH11 (see Fig. 7) conveyed by the pickup roller 22, another sheet SH12 accompanying the sheet SH11 (see Fig. 7) (an example of an accompanying sheet according to the present disclosure).
Specifically, the separation roller 24 includes a shaft portion 24A (see Fig. 4) extending in the front-rear direction D2. The separation roller 24 is fixed to the shaft portion 24A and rotates integrally with the shaft portion 24A. The shaft portion 24A is rotatably supported by a bearing portion (not shown) provided inside the housing 100A. The bearing portion is biased toward the sheet feed roller 23 side by a bias member (not shown) such as a coil spring provided inside the housing 100A. Thus, the separation roller 24 is biased toward the sheet feed roller 23, and a nip portion, that is, the separation portion 28A that nips the sheet SH1 between the separation roller 24 and the sheet feed roller 23 is formed.
When only one sheet SH1 is present at the separation portion 28A, the separation roller 24 rotates by being driven in a rotation direction D8 shown in Fig. 4 by a force transmitted from the sheet SH1 conveyed by the sheet feed roller 23. Further, when the sheets SH11 and SH12 (see Fig. 7) are present at the separation portion 28A, the rotation of the separation roller 24 in the rotation direction D8 is restricted. For example, the sheet supply portion 28 includes a torque limiter that restricts the rotation of the shaft portion 24A in the rotation direction D8 when a torque along the rotation direction D8, that is transmitted to the shaft portion 24A, is smaller than a predetermined threshold value. By restricting the rotation of the separation roller 24 in the rotation direction D8 when the sheets SH11 and SH12 are present at the separation portion 28A, the movement of the sheet SH12 in contact with the separation roller 24 in the sheet conveying direction D5 is restricted by contact friction with the separation roller 24. Thus, the another sheet SH12 that moves together with the sheet SH11 along with the conveyance of the sheet SH11 in contact with the pickup roller 22 is separated from the sheet SH11.
As shown in Fig. 2, the sheet sensor 25 is provided more on the downstream side of the sheet conveying direction D5 than the sheet feed roller 23. The sheet sensor 25 detects the sheet SH1 supplied by the sheet supply portion 28 on the conveying path 27. For example, the sheet sensor 25 includes an actuator that is moved by coming into contact with the sheet SH1 and a reflective or transmissive optical sensor that detects a movement of the actuator. In the image forming apparatus 100, a supply timing of the next sheet SH1 by the sheet supply portion 28 is determined based on a detection timing of the sheet SH1 by the sheet sensor 25. The sheet sensor 25 is an example of a detection portion according to the present disclosure.
The drawing sensor 26 detects drawing out of the sheet feed cassette 21 from the housing 100A. For example, the drawing sensor 26 includes a push switch that changes from an on state to an off state in accordance with the drawing out of the sheet feed cassette 21 from the housing 100A.
Incidentally, in the image forming apparatus 100, a sheet SH3 (see Fig. 4) below the sheet SH2 (see Fig. 4) to be conveyed by the pickup roller 22 may be pulled by the sheet SH2 to be fed out from the stack of sheets SB1 (see Fig. 4). That is, the sheet SH3 to be conveyed next by the pickup roller 22 may move toward the downstream side of the sheet conveying direction D5 from a reference position P1 (see Fig. 4). The reference position P1 is a position at which a tip end of the uppermost sheet SH1 in the stack of sheets SB1 is arranged when the stack of sheets SB1 is lifted by the lift plate 31.
In contrast, a sheet conveying device including an image sensor capable of detecting a protrusion amount of the sheet SH1 from the separation portion 28A is known as the related art. By changing an arrangement position of the image sensor in this sheet conveying device, it is possible to use the image sensor to acquire a pay-out amount of the sheet SH1 from the stack of sheets SB1.
However, in the configuration in which the image sensor is used to acquire the pay-out amount of the sheet SH1 from the stack of sheets SB1, a dedicated sensor needs to be provided for acquiring the pay-out amount of the sheet SH1 from the stack of sheets SB1.
In contrast, in the image forming apparatus 100 according to the embodiment of the present disclosure, it is possible to acquire the pay-out amount of the sheet SH1 from the stack of sheets SB1 without providing a dedicated sensor as will be described below.

[Configuration of control portion 7]

Next, a configuration of the control portion 7 will be described with reference to Fig. 3.
As shown in Fig. 3, the control portion 7 includes a displacement processing portion 41, a first measurement processing portion 42, a second measurement processing portion 43, an acquisition processing portion 44, a determination processing portion 45, and a notification processing portion 46. A device including the sheet feed portion 4 and the control portion 7 is an example of a sheet conveying device according to the present disclosure.
Specifically, a sheet feed control program for causing the CPU 11 of the control portion 7 to execute reset processing (see flowchart shown in Fig. 5) and sheet feed processing (see flowchart shown in Fig. 6) to be described later is stored in advance in the ROM 12 of the control portion 7. It is noted that the sheet feed control program may be recorded on a computer-readable recording medium such as a CD, a DVD, and a flash memory so as to be read from the recording medium to be installed in a storage device such as the storage portion 6.
Then, the control portion 7 uses the CPU 11 to execute the sheet feed control program stored in the ROM 12, to thus function as the respective processing portions described above.
It is noted that some or all of the processing portions included in the control portion 7 may be constituted of electronic circuits. Alternatively, the sheet feed control program may be a program for causing a plurality of processors to function as the respective processing portions included in the control portion 7.
When a predetermined specific timing arrives, the displacement processing portion 41 displaces the stack of sheets SB1 placed in the sheet feed cassette 21 to a position at which the stack of sheets SB1 comes into contact with the pickup roller 22 using the lift plate 31.
For example, the specific timing is a first execution timing of image forming processing after the sheet feed cassette 21 is drawn out from the housing 100A. It is noted that the image forming processing is processing of forming an image on the sheet SH1 supplied by the sheet feed portion 4 using the image forming portion 3.
When the stack of sheets SB1 is lifted by the lift plate 31, the first measurement processing portion 42 measures an elapsed time from a start of supply of the sheet SH1 by the sheet supply portion 28 to a time when the sheet SH1 is detected by the sheet sensor 25.
For example, when the lift of the stack of sheets SB1 by the lift plate 31 is a first lift after the sheet feed cassette 21 is attached to the housing 100A, the first measurement processing portion 42 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25.
For example, the first measurement processing portion 42 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25 every time the stack of sheets SB1 is lifted by the lift plate 31.
For example, the first measurement processing portion 42 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25 at a time when the sheet SH1 is supplied first after the stack of sheets SB1 is lifted by the lift plate 31.
It is noted that the first measurement processing portion 42 may alternatively measure the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25 at a time when a second or subsequent sheet SH1 is supplied after the stack of sheets SB1 is lifted by the lift plate 31. In this case, when a difference between the measured elapsed time and the elapsed time that is based on a previously-acquired average sheet feed speed exceeds a predetermined value, the first measurement processing portion 42 only needs to acquire the elapsed time that is based on the average sheet feed speed in place of the measured elapsed time.
After the measurement by the first measurement processing portion 42, the second measurement processing portion 43 measures an elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25.
For example, after the measurement by the first measurement processing portion 42, the second measurement processing portion 43 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25 every time the sheet SH1 is supplied.
The acquisition processing portion 44 acquires, based on a measurement result obtained by the first measurement processing portion 42 and a measurement result obtained by the second measurement processing portion 43, a pay-out amount of an acquisition target sheet from the stack of sheets SB1 at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement by the second measurement processing portion 43.
For example, the acquisition processing portion 44 acquires the pay-out amount of the acquisition target sheet from the stack of sheets SB1 at the start of supply of the acquisition target sheet based on the last measurement result obtained by the first measurement processing portion 42. Further, the acquisition processing portion 44 acquires the pay-out amount of the acquisition target sheet from the stack of sheets SB1 at the start of supply of the acquisition target sheet every time the elapsed time is measured by the second measurement processing portion 43. It is noted that the acquisition processing portion 44 may acquire the pay-out amount of the acquisition target sheet from the stack of sheets SB1 at the start of supply of the acquisition target sheet based on an average value of a predetermined number of immediately-preceding measurement results obtained by the first measurement processing portion 42.
For example, the acquisition processing portion 44 calculates a conveying speed of the sheet SH1 by the sheet supply portion 28 based on the measurement result obtained by the first measurement processing portion 42 and a first conveying distance from the reference position P1 (see Fig. 4) to the detection position. The first conveying distance is a distance from the reference position P1 to the detection position on the conveying path of the sheet SH1. It is noted that the first conveying distance only needs to be stored in advance in the storage portion 6 or the ROM 12.
In addition, the acquisition processing portion 44 calculates a conveying distance of the acquisition target sheet by the sheet supply portion 28 up to the detection position based on the calculated conveying speed of the sheet SH1 by the sheet supply portion 28 and the measurement result obtained by the second measurement processing portion 43.
Then, the acquisition processing portion 44 acquires a difference between the first conveying distance and the calculated conveying distance of the acquisition target sheet as the pay-out amount of the acquisition target sheet from the stack of sheets SB1 at the start of supply of the acquisition target sheet (the movement amount from the reference position P1).
It is noted that the acquisition processing portion 44 may calculate a ratio of the difference between the measurement result obtained by the first measurement processing portion 42 and the measurement result obtained by the second measurement processing portion 43 to the measurement result obtained by the first measurement processing portion 42, and multiply the calculated ratio by the first conveying distance to acquire the pay-out amount of the acquisition target sheet.
The determination processing portion 45 determines whether or not the acquisition target sheet has protruded beyond the separation portion 28A based on the acquisition result obtained by the acquisition processing portion 44.
For example, when the acquisition result obtained by the acquisition processing portion 44 exceeds a second conveying distance from the reference position P1 (see Fig. 4) to the separation portion 28A, the determination processing portion 45 determines that the acquisition target sheet has protruded beyond the separation portion 28A. The second conveying distance is a distance from the reference position P1 to the separation portion 28A on the conveying path of the sheet SH1. It is noted that the second conveying distance only needs to be stored in advance in the storage portion 6 or the ROM 12.
When it is determined that the acquisition target sheet has protruded beyond the separation portion 28A, the notification processing portion 46 notifies to that effect.
For example, when it is determined that the acquisition target sheet has protruded beyond the separation portion 28A and a predetermined notification condition is satisfied, the notification processing portion 46 notifies that the acquisition target sheet has protruded beyond the separation portion 28A.
For example, the notification condition is a condition in which a frequency at which the acquisition target sheet is determined to have protruded beyond the separation portion 28A exceeds a predetermined value. It is noted that the notification condition may alternatively be a condition in which a protrusion amount of the acquisition target sheet from the separation portion 28A exceeds a predetermined amount. Alternatively, when it is determined that the acquisition target sheet has protruded beyond the separation portion 28A, the notification processing portion 46 may unconditionally notify the fact that the acquisition target sheet has protruded beyond the separation portion 28A.
For example, when it is determined that the acquisition target sheet has protruded beyond the separation portion 28A and the notification condition is satisfied, the notification processing portion 46 causes the operation display portion 5 to display a notification screen that includes a message indicating that the acquisition target sheet has protruded beyond the separation portion 28A.

[Reset processing]

Hereinafter, exemplary procedures of the reset processing executed by the control portion 7 in the image forming apparatus 100 will be described with reference to Fig. 5. Herein, Step S11, Step S12, ... represent numbers of processing procedures (steps) executed by the control portion 7.

First, in Step S11, the control portion 7 determines whether or not the sheet feed cassette 21 has been drawn out from the housing 100A.
Specifically, when a detection signal indicating that the sheet feed cassette 21 has been drawn out is output from the drawing sensor 26, the control portion 7 determines that the sheet feed cassette 21 has been drawn out from the housing 100A.
Herein, when determining that the sheet feed cassette 21 has been drawn out from the housing 100A (Yes in S11), the control portion 7 shifts the processing to Step S12. On the other hand, when determining that the sheet feed cassette 21 has not been drawn out from the housing 100A (No in S11), the control portion 7 waits for the sheet feed cassette 21 to be drawn out from the housing 100A in Step S11.
When the sheet feed cassette 21 is drawn out from the housing 100A, the engagement between the rotation shaft 32A and the joint portion is released, and the lift plate 31 descends by its own weight.

In Step S12, the control portion 7 sets a predetermined measurement flag to OFF.
Specifically, in the image forming apparatus 100, a first storage area used for setting the measurement flag is provided in advance in the storage portion 6. A value of "0" or "1" is stored in the first storage area. The control portion 7 stores the value of "0" in the first storage area to set the measurement flag to OFF.

[Sheet feed processing]

Next, with reference to Fig. 6, an acquisition method according to the present disclosure will be described along with exemplary procedures of the sheet feed processing executed by the control portion 7 in the image forming apparatus 100. It is noted that the sheet feed processing is executed when the execution timing of the image forming processing arrives.

First, in Step S21, the control portion 7 determines whether or not the specific timing has arrived.
Specifically, the control portion 7 determines that the specific timing has arrived when the measurement flag is set to OFF.
Herein, when determining that the specific timing has arrived (Yes in S21), the control portion 7 shifts the processing to Step S22. On the other hand, when determining that the specific timing has not arrived (No in S21), the control portion 7 shifts the processing to Step S27.

In Step S22, the control portion 7 uses the lift plate 31 to displace the stack of sheets SB1 placed in the sheet feed cassette 21 to a position at which the stack of sheets SB1 comes into contact with the pickup roller 22. The processing of Step S22 is executed by the displacement processing portion 41 of the control portion 7.

In Step S23, the control portion 7 causes the sheet supply portion 28 to start supplying the sheet SH1.
An image that is based on image data is formed on the sheet SH1 fed by the processing of Step S23 by the image forming portion 3.

In Step S24, the control portion 7 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25. The processing of Step S24 is an example of a first measurement step according to the present disclosure and is executed by the first measurement processing portion 42 of the control portion 7.
Herein, the sheet SH1 to be fed in the processing of Step S23 is the first sheet SH1 that is conveyed after the sheet feed cassette 21 is drawn out from the housing 100A and the stack of sheets SB1 is set in the sheet feed cassette 21. In other words, the tip end of the sheet SH1 to be fed in the processing of Step S23 is not positioned more on the downstream side of the sheet conveying direction D5 than the reference position P1 (see Fig. 4). Therefore, the first measurement processing portion 42 can more accurately calculate the conveying speed of the sheet SH1 by the sheet supply portion 28 than in the configuration in which the first measurement processing portion 42 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25 at the time when the second or subsequent sheet SH1 is supplied after the stack of sheets SB1 is lifted by the lift plate 31.

In Step S25, the control portion 7 records the elapsed time that has been measured by the processing of Step S24.
Specifically, in the image forming apparatus 100, a second storage area used for recording the elapsed time that has been measured by the processing of Step S24 is provided in advance in the storage portion 6. For example, the control portion 7 stores the elapsed time that has been measured by the processing of Step S24 in the second storage area in association with the execution time of the processing of Step S24, to record the elapsed time.

In Step S26, the control portion 7 sets the measurement flag to ON.
Specifically, the control portion 7 stores the value of "1" in the first storage area to set the measurement flag to ON. Thus, the processing from Step S22 to Step S26 is omitted until the sheet feed cassette 21 is drawn out from the housing 100A.

In Step S27, the control portion 7 determines whether or not a sheet feed timing of the sheet SH1 has arrived.
Specifically, when the sheet SH1 has not been fed after the start of the sheet feed processing, the control portion 7 determines that the sheet feed timing has arrived at the start of the processing of Step S27. Further, when the sheet SH1 has been fed after the start of the sheet feed processing, the control portion 7 determines that the sheet feed timing has arrived when a predetermined time has elapsed since the last detection of the sheet SH1 by the sheet sensor 25.
Herein, when determining that the sheet feed timing has arrived (Yes in S27), the control portion 7 shifts the processing to Step S28. On the other hand, when determining that the sheet feed timing has not arrived (No in S27), the control portion 7 waits for the sheet feed timing to arrive in Step S27.

In Step S28, the control portion 7 causes the sheet supply portion 28 to start supplying the sheet SH1.
An image that is based on image data is formed on the sheet SH1 fed by the processing of Step S28 by the image forming portion 3.

In Step S29, the control portion 7 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25. The processing of Step S29 is an example of a second measurement step according to the present disclosure and is executed by the second measurement processing portion 43 of the control portion 7.

In Step S30, the control portion 7 acquires, based on the latest measurement result out of the measurement results stored in the second storage area and the measurement result obtained by the processing of Step S29 immediately before Step S30, the pay-out amount of the sheet SH1 (the acquisition target sheet) from the stack of sheets SB1 at the start of supply of the acquisition target sheet that has been supplied at the time of the measurement by the processing of Step S29 immediately before Step S30. The processing of Step S30 is an example of an acquisition step according to the present disclosure and is executed by the acquisition processing portion 44 of the control portion 7.
It is noted that the control portion 7 may alternatively acquire the pay-out amount of the sheet SH1 by using an average value of measurement results that have been measured within a predetermined specific period up to a current time point out of the measurement results stored in the second storage area.

In Step S31, the control portion 7 determines whether or not the acquisition target sheet has protruded beyond the separation portion 28A based on the acquisition result obtained by the processing of Step S30 immediately before Step S31. The processing of Step S31 is executed by the determination process portion 45 of the control portion 7.
Herein, when determining that the acquisition target sheet has protruded beyond the separation portion 28A (Yes in S31), the control portion 7 shifts the processing to Step S32. On the other hand, when determining that the acquisition target sheet has not protruded beyond the separation portion 28A (No in S31), the control portion 7 shifts the processing to Step S34.

In Step S32, the control portion 7 determines whether or not the notification condition is satisfied.
Here, when determining that the notification condition is satisfied (Yes in S32), the control portion 7 shifts the processing to Step S33. On the other hand, when determining that the notification condition is not satisfied (No in S32), the control portion 7 shifts the processing to Step S34.

In Step S33, the control portion 7 causes the operation display portion 5 to display the notification screen. The processing of Step S33 is executed by the notification processing portion 46 of the control portion 7.
Thus, it is possible to make the user of the image forming apparatus 100 recognize the functional deterioration of the separation portion 28A. It is noted that the notification screen may include a message indicating that maintenance of the sheet feed roller 23 and the separation roller 24 is necessary.

In Step S34, the control portion 7 determines whether or not the sheet feed of the sheet SH1 has ended.
Specifically, the control portion 7 determines that the sheet feed of the sheet SH1 has ended when all of the sheets SH1 on which images are to be formed by the image forming processing have been fed.
Herein, when determining that the sheet feed of the sheet SH1 has ended (Yes in S34), the control portion 7 ends the sheet feed processing. On the other hand, when determining that the sheet feed of the sheet SH1 has not ended (No in S34), the control portion 7 shifts the processing to Step S27.
In this manner, in the image forming apparatus 100, when the stack of sheets SB1 is lifted by the lift plate 31, the first measurement processing portion 42 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25. Further, after the measurement by the first measurement processing portion 42, the second measurement processing portion 43 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25. Then, based on the measurement result obtained by the first measurement processing portion 42 and the measurement result obtained by the second measurement processing portion 43, the pay-out amount of the acquisition target sheet from the stack of sheets SB1 at the start of supply of the acquisition target sheet supplied at the time of the measurement by the second measurement processing portion 43 is acquired. Thus, it is possible to acquire the pay-out amount of the sheet SH1 from the stack of sheets SB1 without providing a dedicated sensor.
Furthermore, in the image forming apparatus 100, the first measurement processing portion 42 measures the elapsed time from the start of supply of the sheet SH1 by the sheet supply portion 28 to the time when the sheet SH1 is detected by the sheet sensor 25 every time the stack of sheets SB1 is lifted by the lift plate 31. Then, based on the last measurement result obtained by the first measurement processing portion 42, the pay-out amount of the acquisition target sheet from the stack of sheets SB1 is acquired. Thus, even when the conveying speed of the sheet SH1 by the sheet supply portion 28 changes due to a change in either one or both of the size and type of the sheet SH1, it is possible to acquire the pay-out amount of the sheet SH1 from the stack of sheets SB1 based on the conveying speed after the change. Moreover, even when the conveying speed of the sheet SH1 by the sheet supply portion 28 decreases due to deterioration over time, it is possible to acquire the pay-out amount of the sheet SH1 from the stack of sheets SB1 based on the conveying speed after the decrease.
It is noted that the second storage area may store an elapsed time associated with a combination of the type and size of the sheet SH1. In this case, the acquisition processing portion 44 may acquire the pay-out amount of the acquisition target sheet by using an average value of a plurality of elapsed times that have been measured within the specific period up to the current time point out of a plurality of elapsed times having a common combination of the type and size of the sheet SH1.
Further, the lift plate 31 may be configured to descend every time the image forming processing ends. In this case, when the sheet SH1 fed out from the stack of sheets SB1 returns to the reference position P1 by its own weight, a reverse rotation of the pickup roller 22 and the sheet feed roller 23, or the like while the lift plate 31 descends, the specific timing may be the execution timing of the image forming processing.
Furthermore, the lift portion according to the present disclosure is not limited to a flat plate-like member and only needs to be a member including a support surface that supports a bottom surface of the stack of sheets SB1. In addition, the conveying member according to the present disclosure is not limited to a roller-type member and may alternatively be a belt-like member.
Moreover, the present disclosure may also be applied to an inkjet-type image forming apparatus.
Furthermore, the present disclosure may also be applied to the ADF 1.

[Notes of disclosure]

Hereinafter, a general outline of the disclosure extracted from the embodiment described above will be noted. It is noted that the respective configurations and processing functions described in the notes below can be sorted and arbitrarily combined as appropriate.
<Note 1>
A sheet conveying device, including: a lift portion which lifts a stack of sheets; a sheet supply portion which includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies a sheet that comes into contact with the conveying member to a conveying path; a detection portion which detects the sheet supplied by the sheet supply portion on the conveying path; a first measurement processing portion which measures, when the stack of sheets is lifted by the lift portion, an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion; a second measurement processing portion which measures, after the measurement by the first measurement processing portion, an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion; and an acquisition processing portion which acquires, based on a measurement result obtained by the first measurement processing portion and a measurement result obtained by the second measurement processing portion, a pay-out amount of an acquisition target sheet from the stack of sheets at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement by the second measurement processing portion.

The sheet conveying device according to note 1, including: a sheet storing portion which is detachably provided in a housing of the sheet conveying device and stores the stack of sheets, in which the lift portion is provided in the sheet storing portion, and when the lift of the stack of sheets by the lift portion is a first lift after the sheet storing portion is attached to the housing, the first measurement processing portion measures the elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion.

The sheet conveying device according to note 1 or 2, in which the first measurement processing portion measures the elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion every time the stack of sheets is lifted by the lift portion, and the acquisition processing portion acquires, based on a last measurement result obtained by the first measurement processing portion, the pay-out amount of the acquisition target sheet from the stack of sheets at the time of the start of supply of the acquisition target sheet.

The sheet conveying device according to any one of notes 1 to 3, in which the first measurement processing portion measures, at a time when the sheet is first supplied after the stack of sheets is lifted by the lift portion, the elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion.

The sheet conveying device according to any one of notes 1 to 4, in which the sheet supply portion includes a separation portion which separates, from the sheet conveyed by the conveying member, an accompanying sheet accompanying the sheet, and the sheet conveying device includes: a determination processing portion which determines, based on an acquisition result obtained by the acquisition processing portion, whether or not the acquisition target sheet has protruded beyond the separation portion; and a notification processing portion which, when it is determined that the acquisition target sheet has protruded beyond the separation portion, notifies to that effect.

An image forming apparatus, including: the sheet conveying device according to any one of notes 1 to 5; and an image forming portion which forms an image on the sheet conveyed by the sheet conveying device.

An acquisition method executed in a sheet conveying device including a lift portion which lifts a stack of sheets, a sheet supply portion which includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies a sheet that comes into contact with the conveying member to a conveying path, and a detection portion which detects the sheet supplied by the sheet supply portion on the conveying path, the acquisition method including: a first measurement step of measuring, when the stack of sheets is lifted by the lift portion, an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion; a second measurement step of measuring, after the measurement in the first measurement step, an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion; and an acquisition step of acquiring, based on a measurement result obtained in the first measurement step and a measurement result obtained in the second measurement step, a pay-out amount of an acquisition target sheet from the stack of sheets at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement in the second measurement step.
It is to be understood that the embodiments herein are illustrative and not restrictive, since the scope of the disclosure is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.

Claims

A sheet conveying device, comprising:
a lift portion (31) which lifts a stack of sheets (SB1);

a sheet supply portion (28) which includes a conveying member (22) which rotates while being in contact with an upper surface of the stack of sheets (SB1) lifted by the lift portion (31), and supplies a sheet (SH1) that comes into contact with the conveying member (22) to a conveying path (27);

a detection portion (25) which detects the sheet (SH1) supplied by the sheet supply portion (28) on the conveying path (27);

a first measurement processing portion (42) which measures, when the stack of sheets (SB1) is lifted by the lift portion (31), an elapsed time from a start of supply of the sheet (SH1) by the sheet supply portion (28) to a time when the sheet (SH1) is detected by the detection portion (25);

a second measurement processing portion (43) which measures, after the measurement by the first measurement processing portion (42), an elapsed time from the start of supply of the sheet (SH1) by the sheet supply portion (28) to the time when the sheet (SH1) is detected by the detection portion (25); and

an acquisition processing portion (44) which acquires, based on a measurement result obtained by the first measurement processing portion (42) and a measurement result obtained by the second measurement processing portion (43), a pay-out amount of an acquisition target sheet from the stack of sheets (SB1) at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement by the second measurement processing portion (43).
The sheet conveying device according to claim 1, comprising:
a sheet storing portion (21) which is detachably provided in a housing (100A) of the sheet conveying device and stores the stack of sheets (SB1), wherein

the lift portion (31) is provided in the sheet storing portion (21), and

when the lift of the stack of sheets (SB1) by the lift portion (31) is a first lift after the sheet storing portion (21) is attached to the housing (100A), the first measurement processing portion (42) measures the elapsed time from the start of supply of the sheet (SH1) by the sheet supply portion (28) to the time when the sheet (SH1) is detected by the detection portion (25).
The sheet conveying device according to claim 1 or 2, wherein
the first measurement processing portion (42) measures the elapsed time from the start of supply of the sheet (SH1) by the sheet supply portion (28) to the time when the sheet (SH1) is detected by the detection portion (25) every time the stack of sheets (SB1) is lifted by the lift portion (31), and

the acquisition processing portion (44) acquires, based on a last measurement result obtained by the first measurement processing portion (42), the pay-out amount of the acquisition target sheet from the stack of sheets (SB1) at the time of the start of supply of the acquisition target sheet.
The sheet conveying device according to any one of claim 1 to 3, wherein
the first measurement processing portion (42) measures, at a time when the sheet (SH1) is first supplied after the stack of sheets (SB1) is lifted by the lift portion (31), the elapsed time from the start of supply of the sheet (SH1) by the sheet supply portion (28) to the time when the sheet (SH1) is detected by the detection portion (25).
The sheet conveying device according to any one of claim 1 to 4, wherein
the sheet supply portion (28) includes

a separation portion (28A) which separates, from the sheet (SH11) conveyed by the conveying member (22), an accompanying sheet (SH12) accompanying the sheet (SH11), and

the sheet conveying device comprises:
a determination processing portion (45) which determines, based on an acquisition result obtained by the acquisition processing portion (44), whether or not the acquisition target sheet has protruded beyond the separation portion (28A); and

a notification processing portion (46) which, when it is determined that the acquisition target sheet has protruded beyond the separation portion (28A), notifies to that effect.
An image forming apparatus (100), comprising:
the sheet conveying device according to any one of claim 1 to 5; and

an image forming portion (3) which forms an image on the sheet (SH1) conveyed by the sheet conveying device.
An acquisition method executed in a sheet conveying device including a lift portion (31) which lifts a stack of sheets (SB1), a sheet supply portion (28) which includes a conveying member (22) which rotates while being in contact with an upper surface of the stack of sheets (SB1) lifted by the lift portion (31), and supplies a sheet (SH1) that comes into contact with the conveying member (22) to a conveying path (27), and a detection portion (25) which detects the sheet (SH1) supplied by the sheet supply portion (28) on the conveying path (27), the acquisition method comprising:
a first measurement step of measuring, when the stack of sheets (SB1) is lifted by the lift portion (31), an elapsed time from a start of supply of the sheet (SH1) by the sheet supply portion (28) to a time when the sheet (SH1) is detected by the detection portion (25);

a second measurement step of measuring, after the measurement in the first measurement step, an elapsed time from the start of supply of the sheet (SH1) by the sheet supply portion (28) to the time when the sheet (SH1) is detected by the detection portion (25); and

an acquisition step of acquiring, based on a measurement result obtained in the first measurement step and a measurement result obtained in the second measurement step, a pay-out amount of an acquisition target sheet from the stack of sheets (SB1) at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement in the second measurement step.