Sheet Conveying Device Capable of Acquiring Pay-Out Amount of Sheet from Stack of Sheets Without Providing Dedicated Sensor, an Image Forming Apparatus, and Acquisition Method

This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2024-102055 filed on Jun. 25, 2024, the entire contents of which are incorporated herein by reference.

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.

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.

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.

First, a configuration of an image forming apparatusaccording to an embodiment of the present disclosure will be described with reference toto. Herein,is a perspective view showing an outer appearance of the image forming apparatus. Further,is a cross-sectional view showing an internal configuration of the image forming apparatus. Furthermore,is an enlarged view of a sheet supply portionshown in.

It is noted that for convenience of descriptions, a vertical direction in a state where the image forming apparatusis installed in a usable state (a state shown in) is defined as an up-down direction D. In addition, a front-rear direction Dis defined with a surface of the image forming apparatuson a near left side of a sheet surface shown inbeing a front surface (front side). In addition, a left-right direction Dis defined using the front surface of the image forming apparatusin the installed state as a reference.

The image forming apparatusis 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, the image forming apparatusincludes an ADF (Auto Document Feeder), an image reading portion, an image forming portion, a sheet feed portion, an operation display portion, a storage portion, and a control portion.

The image forming portion, the sheet feed portion, the storage portion, and the control portionare housed in a housingA (seeand) of the image forming apparatus. The housingA is formed in a substantially rectangular parallelepiped shape. The ADFand the image reading portionare provided on an upper side of the housingA (seeand). The operation display portionis provided on a front side of the housingA (see).

The ADFconveys a document sheet from which an image is to be read by the image reading portion. The ADFincludes a document sheet setting portion, a plurality of conveying rollers, a document sheet holder, and a sheet discharge portion.

The image reading portionreads an image of a document sheet. That is, the image reading portionrealizes the scanning function. The image reading portionincludes a document sheet table, a light source, a plurality of mirrors, an optical lens, and a CCD (Charge Coupled Device).

The image forming portionforms an image that is based on image data on a sheet SH(see) supplied from the sheet feed portion. That is, the image forming portionrealizes the printing function. Specifically, the image forming portionforms an image using electrophotography. The image forming portionincludes 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 portionis a user interface of the image forming apparatus. The operation display portionincludes a display portion and an operation portion. The display portion displays various types of information in response to control instructions from the control portion. 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 portionaccording to user operations. For example, the operation portion includes an operation key and a touch panel.

The storage portionis a nonvolatile storage device. For example, the storage portionis a nonvolatile memory such as a flash memory.

The control portioncollectively controls the image forming apparatus. As shown in, the control portionincludes a CPU, a ROM, and a RAM. The CPUis a processor that executes various types of arithmetic processing. The ROMis a nonvolatile storage device in which information such as control programs for causing the CPUto execute various types of processing is stored in advance. The RAMis 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. In the control portion, the CPUexecutes the various control programs stored in advance in the ROM. Thus, the control portioncollectively controls the image forming apparatus. It is noted that the control portionmay be constituted of an electronic circuit such as an integrated circuit (ASIC). Alternatively, the control portionmay be a control portion provided separately from a main control portion that collectively controls the image forming apparatus.

The sheet feed portionsupplies a sheet SH(see) to the image forming portion.

As shown inand, the sheet feed portionincludes a sheet feed cassette, a pickup roller, a sheet feed roller, a separation roller, a sheet sensor, a drawing sensor, and a conveying path.

A stack of sheets SB(see) is placed in the sheet feed cassette. For example, the stack of sheets SBincluding the sheets SHsuch as paper, coated paper, postcards, envelopes, and OHP sheets is placed in the sheet feed cassette. As shown inand, the sheet feed cassetteis provided at a bottom portion of the housingA. In addition, the sheet feed cassetteis provided so as to be capable of being drawn out from the housingA in a drawing direction D(see) along the front-rear direction D. The sheet feed cassettestores the stack of sheets SB. The sheet feed cassetteis detachably provided in the housingA. The sheet feed cassetteis an example of a sheet storing portion according to the present disclosure.

As shown in, the sheet feed cassetteincludes a lift plate, a lifting and lowering mechanism, an end cursor, and a pair of side cursors.

The lift platelifts up the stack of sheets SB(see) placed in the sheet feed cassette. The lift plateis a flat plate-like member provided at the bottom portion of the sheet feed cassette. The stack of sheets SBis placed on an upper surface of the lift plate. The lift plateis provided to be rotatable about a rotation shaftA (see) extending in the front-rear direction D. Specifically, a right end portion of the lift plateis supported rotatably about the rotation shaftA. The lift plateis an example of a lift portion according to the present disclosure.

The lifting and lowering mechanismlifts and lowers the lift plate. As shown in, the lifting and lowering mechanismincludes a rotation shaftA and a push-up plateB. The rotation shaftA extends in the front-rear direction D. The push-up plateB is provided to extend from the rotation shaftA toward a direction orthogonal to the extension direction of the rotation shaftA. The push-up plateB is formed in a flat plate shape that is elongated in the front-rear direction D. The rotation shaftA and the push-up plateB are provided below the lift plate.

A rear end portion of the rotation shaftA is coupled to a motor (not shown) provided outside the sheet feed cassettevia a joint portion (not shown) provided outside the sheet feed cassette. Upon receiving a rotational driving force supplied from the motor via the joint portion, the rotation shaftA and the push-up plateB rotate in a second rotation direction Dshown in. When the rotation shaftA and the push-up plateB rotate in the second rotation direction D, the lift plateis pushed up by the push-up plateB to thus rotate in a first rotation direction D(see) shown in. Thus, the stack of sheets SBplaced on the upper surface of the lift plateis lifted upwardly.

The joint portion is restricted from rotating in a direction opposite to the second rotation direction D. 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 D. By restricting the joint portion from rotating in the direction opposite to the second rotation direction D, the rotation of the rotation shaftA engaged with the joint portion in the direction opposite to the second rotation direction Dis also restricted. This restricts lowering of the lift plateby its own weight.

When the sheet feed cassetteis drawn out from the housingA in the drawing direction D, the engagement between the rotation shaftA and the joint portion is released. Thus, the restriction of the rotation of the rotation shaftA and the push-up plateB in the direction opposite to the second rotation direction Dby the joint portion is released, and the lift plateis lowered by its own weight.

The end cursoris provided so as to be movable along a sheet conveying direction Dshown in. The end cursorcauses the stack of sheets SBplaced in the sheet feed cassetteto abut against a wall surfaceA (see) of the sheet feed cassetteon a downstream side of the sheet conveying direction D, to adjust a position of the stack of sheets SBin the sheet conveying direction D. The pair of side cursorsare provided to interlock with each other so as to approach or move away from each other along a width direction of the sheet SHorthogonal to the sheet conveying direction D. The pair of side cursorssandwich and hold the stack of sheets SBplaced in the sheet feed cassetteto adjust the position of the sheets SHin the width direction.

As shown inand, the pickup rolleris provided above the lift plate. The pickup rollerrotates while being in contact with the upper surface of the stack of sheets SBlifted by the lift plate, thereby conveying an uppermost sheet SH(see) in the stack of sheets SBto a separation portionA (see). Herein, the separation portionA is a nip portion formed between the sheet feed rollerand the separation roller. The pickup rollerconveys the sheet SHin the sheet conveying direction D(see). The sheet conveying direction Dis a direction orthogonal to the front-rear direction D. The pickup rolleris an example of a conveying member according to the present disclosure.

Specifically, the pickup rolleris provided to be rotatable about a shaft extending in the front-rear direction D. The pickup rollerrotates by receiving a rotational driving force supplied from a motor (not shown) while being in contact with the upper surface of the sheet SH. Thus, the pickup rollerapplies a conveying force in the sheet conveying direction Dto the sheet SHin contact with the pickup roller.

The pickup roller, the sheet feed roller, and the separation rollerconstitute the sheet supply portion(seeand) that supplies the sheet SHin contact with the pickup rollerto the conveying path(see). The conveying pathis a movement path of the sheet SHthat is provided from the sheet supply portionto the image forming portion.

As shown inand, the sheet feed rolleris provided more on the downstream side of the sheet conveying direction Dthan the pickup roller. The sheet feed rollercomes into contact with the upper surface of the sheet SH(see) conveyed by the pickup rollerand conveys the sheet SHbeyond a detection position of the sheet SHby the sheet sensor(see). The sheet feed rollerconveys the sheet SHin the sheet conveying direction D.

Specifically, the sheet feed rolleris provided to be rotatable about a shaft extending in the front-rear direction D. The sheet feed rollerrotates by receiving a rotational driving force supplied from a motor (not shown) while being in contact with the upper surface of the sheet SH. Thus, the sheet feed rollerapplies a conveying force in the sheet conveying direction Dto the sheet SHin contact with the sheet feed roller.

As shown inand, the separation rolleris provided below the sheet feed rollerwhile opposing the sheet feed roller. The separation rollerforms the separation portionA (see) with the sheet feed roller. The separation portionA separates, from a sheet SH(see) conveyed by the pickup roller, another sheet SHaccompanying the sheet SH(see) (an example of an accompanying sheet according to the present disclosure).

Specifically, the separation rollerincludes a shaft portionA (see) extending in the front-rear direction D. The separation rolleris fixed to the shaft portionA and rotates integrally with the shaft portionA. The shaft portionA is rotatably supported by a bearing portion (not shown) provided inside the housingA. The bearing portion is biased toward the sheet feed rollerside by a bias member (not shown) such as a coil spring provided inside the housingA. Thus, the separation rolleris biased toward the sheet feed roller, and a nip portion, that is, the separation portionA that nips the sheet SHbetween the separation rollerand the sheet feed rolleris formed.

When only one sheet SHis present at the separation portionA, the separation rollerrotates by being driven in a rotation direction Dshown inby a force transmitted from the sheet SHconveyed by the sheet feed roller. Further, when the sheets SHand SH(see) are present at the separation portionA, the rotation of the separation rollerin the rotation direction Dis restricted. For example, the sheet supply portionincludes a torque limiter that restricts the rotation of the shaft portionA in the rotation direction Dwhen a torque along the rotation direction D, that is transmitted to the shaft portionA, is smaller than a predetermined threshold value. By restricting the rotation of the separation rollerin the rotation direction Dwhen the sheets SHand SHare present at the separation portionA, the movement of the sheet SHin contact with the separation rollerin the sheet conveying direction Dis restricted by contact friction with the separation roller. Thus, the another sheet SHthat moves together with the sheet SHalong with the conveyance of the sheet SHin contact with the pickup rolleris separated from the sheet SH.

As shown in, the sheet sensoris provided more on the downstream side of the sheet conveying direction Dthan the sheet feed roller. The sheet sensordetects the sheet SHsupplied by the sheet supply portionon the conveying path. For example, the sheet sensorincludes an actuator that is moved by coming into contact with the sheet SHand a reflective or transmissive optical sensor that detects a movement of the actuator. In the image forming apparatus, a supply timing of the next sheet SHby the sheet supply portionis determined based on a detection timing of the sheet SHby the sheet sensor. The sheet sensoris an example of a detection portion according to the present disclosure.

The drawing sensordetects drawing out of the sheet feed cassettefrom the housingA. For example, the drawing sensorincludes a push switch that changes from an on state to an off state in accordance with the drawing out of the sheet feed cassettefrom the housingA.

Incidentally, in the image forming apparatus, a sheet SH(see) below the sheet SH(see) to be conveyed by the pickup rollermay be pulled by the sheet SHto be fed out from the stack of sheets SB(see). That is, the sheet SHto be conveyed next by the pickup rollermay move toward the downstream side of the sheet conveying direction Dfrom a reference position P(see). The reference position Pis a position at which a tip end of the uppermost sheet SHin the stack of sheets SBis arranged when the stack of sheets SBis lifted by the lift plate.

In contrast, a sheet conveying device including an image sensor capable of detecting a protrusion amount of the sheet SHfrom the separation portionA 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 SHfrom the stack of sheets SB.

However, in the configuration in which the image sensor is used to acquire the pay-out amount of the sheet SHfrom the stack of sheets SB, a dedicated sensor needs to be provided for acquiring the pay-out amount of the sheet SHfrom the stack of sheets SB.

In contrast, in the image forming apparatusaccording to the embodiment of the present disclosure, it is possible to acquire the pay-out amount of the sheet SHfrom the stack of sheets SBwithout providing a dedicated sensor as will be described below.

Next, a configuration of the control portionwill be described with reference to.

As shown in, the control portionincludes a displacement processing portion, a first measurement processing portion, a second measurement processing portion, an acquisition processing portion, a determination processing portion, and a notification processing portion. A device including the sheet feed portionand the control portionis an example of a sheet conveying device according to the present disclosure.

Specifically, a sheet feed control program for causing the CPUof the control portionto execute reset processing (see flowchart shown in) and sheet feed processing (see flowchart shown in) to be described later is stored in advance in the ROMof the control portion. 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.

Then, the control portionuses the CPUto execute the sheet feed control program stored in the ROM, 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 portionmay 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.

When a predetermined specific timing arrives, the displacement processing portiondisplaces the stack of sheets SBplaced in the sheet feed cassetteto a position at which the stack of sheets SBcomes into contact with the pickup rollerusing the lift plate.