Medium Feed Apparatus to Put Separation Roller on Hold Until Front End of Medium Passes Separation Part

This is a continuation application of U.S. patent application Ser. No. 18/352,735, filed Jul. 14, 2023, which claims priority to and benefit of prior Japanese Patent Application No. 2022-133667, filed on Aug. 24, 2023, the entire contents of which are incorporated herein by reference.

Embodiments discussed in the present specification relate to feed a medium.

A scanner or other medium feed apparatus feeds and captures images of a plurality of sheets of a medium while separating them into individual sheets. If multi-feed of the medium occurs in such a medium feed apparatus, the user has to take out the medium from inside the housing and reset it on the stacking tray. In order to improve the user friendliness, it is desirable to reduce the possibility of multi-feed of the medium occurring.

A feed apparatus, in which the rotational speed of a retard roller is detected and a feeding means is controlled to continue the feed operation of a recording material if the rotational speed is a first value or more and stop the feed operation if it is less than the first value, has been disclosed.

According to some embodiments, a medium feed apparatus includes a feed roller to feed a medium, a separation roller located facing the feed roller, a motor configured to generate a drive force for rotating the separation roller in an opposite direction to a medium feed direction, a first sensor located at an upstream side from the feed roller and separation roller in a medium conveyance direction, a second sensor located at a downstream side from the feed roller and separation roller in the medium conveyance direction, a third sensor configured to detect rotation of the separation roller, and a processor to rotate the feed roller in the medium feed direction to feed the medium. The processor controls the motor so as to put the separation roller on hold from when starting the feed of the medium to when the second sensor detects a front end of the medium and generate the drive force from when the second sensor detects the front end of the medium to when the first sensor detects a back end of the medium, and controls the motor to stop the feed roller while generating the drive force if the third sensor detects rotation of the separation roller in the opposite direction to the medium feed direction during feed of the medium.

According to some embodiments, a medium feed method includes rotating a feed roller in a medium feed direction to feed a medium, controlling a motor to put a separation roller located facing the feed roller on hold from when starting the feed of the medium to when a second sensor located at a downstream side from the feed roller and separation roller in a medium conveyance direction detects a front end of the medium and generate a drive force for rotating the separation roller in an opposite direction to the medium feed direction from when the second sensor detects the front end of the medium to when a first sensor located at an upstream side from the feed roller and separation roller in the medium conveyance direction detects a back end of the medium, and controlling the motor to stop the feed roller while generating the drive force if a third sensor detects rotation of the separation roller in the opposite direction to the medium feed direction during feed of the medium.

According to some embodiments, a computer-readable, non-transitory medium stores executable instructions for feeding a medium. The executable instructions include rotating a feed roller in a medium feed direction to feed the medium, controlling a motor to put a separation roller located facing the feed roller on hold from when starting the feed of the medium to when a second sensor located at a downstream side from the feed roller and separation roller in a medium conveyance direction detects a front end of the medium and generate a drive force for rotating the separation roller in an opposite direction to the medium feed direction from when the second sensor detects the front end of the medium to when a first sensor located at an upstream side from the feed roller and separation roller in the medium conveyance direction detects a back end of the medium, and controlling the motor to stop the feed roller while generating the drive force if a third sensor detects rotation of the separation roller in the opposite direction to the medium feed direction during feed of the medium.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are not restrictive of the invention, as claimed.

Hereinafter, a medium feed apparatus, medium feed method and computer-readable, non-transitory medium according to an embodiment, will be described with reference to the drawings. However, it should be noted that the technical scope of the invention is not limited to these embodiments, and extends to the inventions described in the claims and their equivalents.

is a perspective view illustrating an example of a medium feed apparatus constituted as an image scanner. The medium feed apparatusconveys a document as a medium and captures an image of it. The medium is printing paper, thick paper, a card, etc. The medium feed apparatusmay be a facsimile, copier, multifunction peripheral (MFP), etc.

In, the arrow Aindicates a substantially vertical direction (height direction), the arrow Aindicates a medium conveyance direction, the Aindicates a medium ejection direction, and the arrow Aindicates a width direction perpendicular to the medium conveyance direction Aor the medium ejection direction A. Below, “upstream” means upstream in the medium conveyance direction Aor medium ejection direction A, while “downstream” means downstream in the medium conveyance direction Aor medium ejection direction A.

The medium feed apparatusis provided with a first housing, second housing, stacking tray, ejection tray, operating device, display device, etc.

The second housingis located at the inside of the first housingand engaged with the first housing rotatably by a hinge to enable it to be opened and closed at the time of jamming of the medium or the time of cleaning the inside of the medium feed apparatus, etc.

The stacking trayengages with the first housingto be able to stack the medium to be conveyed. The stacking trayis provided at the side surface of the first housingat the medium supply side movably in the height direction A. When not conveying the medium, the stacking trayis located at the bottom end so that the medium is easily stacked. When conveying the medium, the stacking trayis raised to the position where a later explained pick roller contacts the media stacked on the top.

The ejection trayis formed on the second housing. The ejection trayhas a stacking surfacefor stacking the medium and stacks the medium ejected from an ejection opening of the first housingand the second housing.

The operating devicehas buttons or other input devices and an interface circuit acquiring signals from the input devices, receiving input operations of a user, and outputting operating signals corresponding to the input operations of a user. The display devicehas a display including liquid crystals, organic Electro-Luminescence (El), etc., and an interface circuit outputting image data to the display and displaying the image data on the display. Note that the display devicemay be a liquid crystal display with a touch panel function. In that case, the operating devicehas an interface circuit for acquiring input signals from the touch panel.

is a view for explaining an example of a conveyance path inside of an example of a medium feed apparatus.

The conveyance path inside of the medium feed apparatushas a first medium sensor, first encoder, pick roller, feed roller, separation roller, second encoder, second medium sensor, third medium sensor, first skew sensor, second skew sensor, ultrasonic sensor, first to sixth conveyance rollersto, first to sixth driven rollersto, a fourth medium sensor, imaging device, etc.

Note that, the numbers of the pick roller, feed roller, separation roller, first to sixth conveyance rollersto, and/or first to sixth driven rollerstoare not limited to one and may be plural. In this case, the plurality of feed rollers, separation rollers, first to sixth conveyance rollersto, and/or first to sixth driven rollerstoare located in the width direction A.

The second housingis located facing the first housingwith the medium conveyance path therebetween. The surface of the first housingfacing the second housingforms a first guideof the medium conveyance path, while the surface of the second housingfacing the first housingforms a second guideof the medium conveyance path.

The first medium sensoris located at the stacking tray, i.e., at an upstream side from the feed rollerand separation roller, and detects the stacking state of the medium at the stacking tray. The first medium sensordetermines whether the stacking trayhas the medium by a contact detection sensor which generates a predetermined current when the medium contacts or when the medium does not contact. The first medium sensorgenerates and outputs a first medium signal with a signal value changing between a state where the stacking trayhas the medium and a state where the stacking traydoes not have the medium. Note that the first medium sensoris not limited to a contact detection sensor. A photo detection sensor or any other sensor able to detect the presence of the medium may be used as the first medium sensor.

The first encoderis an example of a first sensor. The first encoderis located at the second housingat an upstream side from the feed rollerand separation rollerin the medium conveyance direction Aand detects a back end of the medium being fed by contacting and detecting the movement of the medium. In particular, the first encoderis located at an upstream side from the pick rollerin the medium conveyance direction A, in particular in the vicinity of the pick roller. The first encoderhas a disk formed with a large number of slits (openings for passing light) and provided so as to rotate in accordance with the medium being fed, and a light emitter and light receiver provided so as to face each other with the disk in between. The light emitter is an LED (light emitting diode), etc., and emits light toward the disk (light receiver). The light receiver is a photodiode, etc., and receives light emitted from the light emitter through the disk. The light receiver detects the number of changes within a predetermined time period from a state where there is a slit between the light emitter and light receiver to a state where there is no slit and light is blocked by the disk. The light receiver multiplies the detected number of changes with a distance of movement of the outer circumferential surface of the first encoderwhen the disk rotates by the distance between two mutually adjoining slits to detect the distance of movement of the medium being fed. The first encodergenerates and outputs a distance signal indicating the distance of movement detected. When the back end of the medium being fed passes the position of the first encoder, the distance of movement of the medium changes from a value larger than 0 to 0, so the first encodercan detect the back end of the medium from the distance of movement of the medium. Note that, the first encoderis not limited to an optical type encoder and may be a mechanical type encoder, magnetic type encoder, electromagnetic induction type encoder, or any other encoder.

The pick rolleris located at the second housingat the upstream side from the feed rollerand separation rollerin the medium conveyance direction A. The pick rollercontacts the sheet at the topmost side in the medium stacked on the stacking traywhen the stacking trayhas risen to substantially the same height as the medium conveyance path and conveys the sheet of the medium toward the downstream side. A one-way clutch is provided between the pick rollerand the motor imparting a drive force to the pick roller, so that the rotation of the pick rollerin the opposite direction to the medium feed direction All is restricted.

The feed rolleris provided inside the second housingat the downstream side from the pick rollerand feeds the medium stacked on the stacking trayand fed by the pick rollertoward the further downstream side. If a plurality of feed rollersare provided, the individual feed rollersare provided to rotate independently by separate motors. The feed rollersmay be provided so as to rotate integrally by a common motor. A one-way clutch is provided between each feed rollerand the motor imparting drive force to the feed roller, so that the rotation of the feed rollerin a direction opposite to the medium feed direction Ais restricted.

The separation rolleris located inside the first housingfacing the feed roller. The separation rolleris a so-called brake roller or retard roller and is provided rotatably in an direction Aopposite to the medium feed direction or to be stoppable. The feed rollerand separation rollerfunction as a separation part for separating and feeding the medium one by one. The feed rolleris located above the separation roller, and the medium feed apparatusfeeds the medium by the so-called top pick method. Note that the feed rollermay be located below the separation roller, and the medium feed apparatusmay feed the medium by the so-called bottom pick method.

A torque limiter is provided between the separation rollerand the motor imparting drive force to the separation rollerfor limiting the torque acting on the separation roller. The limit value of the torque limiter is set to a value such that the rotational force through the torque limiter is cut when there is a single sheet of the medium, and transmitted when there are a plurality of sheets of the medium. Therefore, if just one sheet of the medium is being conveyed, the separation rollerdoes not rotate with the drive force from the motor, but is driven by the feed roller. On the other hand, if a plurality of sheets of the medium are being conveyed, the separation rollerrotates in the direction Aopposite to the medium feed direction to separate the sheet of the medium contacting the feed rollerfrom other sheets of the medium and prevent the occurrence of multi-feed. At this time, the outer circumferential surface of the separation rollermay apply force in direction Aopposite to the medium feed direction to the medium by stopping without rotating in the opposite direction Aof the medium feed direction.

The separation rolleris supported by an armat the first housing. The separation rolleris attached to one end of the arm. The other end of the armis attached to the first housing. The armis provided rotatably (swingably) at the first housing. The armis given a biasing force upward, i.e., in a direction where the separation rollermoves toward the feed rollerside, by a spring member or rubber member or other biasing member. Further, a rotational force is applied to the armby the drive force from a motor. The medium feed apparatusadjusts the pressing force with which the separation rollerpresses against the feed rollerby rotating (swinging) the arm.

The second encoderis one example of a third sensor. The second encoderis attached to a shaft of the rotational axis of the separation rollerin the second housingand detects rotation of the separation roller. The second encoderhas a disk formed with a large number of slits (openings for passing light) and provided so as to rotate along with rotation of the separation rollerand a light emitter and light receiver provided so as to face each other with the disk in between. The light emitter is an LED, etc., and emits light toward the disk (light receiver). The light receiver is a photodiode, etc., and receives light emitted by the light emitter through the disk. The light receiver detects the number of changes within a predetermined time period from a state where there is there a slit between the light emitter and the light receiver to a state where there is no slit there and light is blocked by the disk. The light receiver multiplies the detected number of changes with the distance by which the outer circumferential surface of the separation rollermoves when the disk rotates by the distance between two mutually adjoining slits to detect the distance of movement of the outer circumferential surface of the separation roller. Further, a fixed slit is provided between the light emitter and the light receiver so that the output signal (pulse) becomes biphasic. The light receiver detects the direction of rotation of the disk by the rising timings of the output signals of the phases. The second encodergenerates and outputs a rotation signal indicating the detected distance of movement and rotational direction of the disk (stop/forward direction/backward direction). Note that, the second encoderis not limited to an optical type encoder and may be a mechanical type encoder, magnetic type encoder, electromagnetic induction type encoder, or any other encoder.

The second medium sensoris one example of a second sensor. The second medium sensoris located at a downstream side from the feed rollerand separation rollerand the upstream side from the first conveyance rollerand the first driven rollerin the medium conveyance direction A, and detects a medium. In particular, the second medium sensoris located in the vicinity of the feed rollerand separation roller. The second medium sensorincludes a light emitter and a light receiver provided at one side of the medium conveyance path and a light guide provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light emitter is an LED, etc., and emits light toward the medium conveyance path. The light receiver is a photodiode, etc., and receives light emitted by the light emitter and guided by the light guide. Based on the intensity of the light received by the light receiver, the second medium sensorgenerates and outputs a second medium signal with a signal value changing between the state where there is the medium at the position of the second medium sensorand the state where there is no medium.

The third medium sensoris one example of a fourth sensor. The third medium sensoris located at a downstream side from the feed rollerand separation rollerand the upstream side from the first conveyance rollerand the first driven rollerin the medium conveyance direction A, and detects a medium. In other words, the third medium sensoris located between the feed rollerand separation rollerand the first conveyance rollerand the first driven rollerin the medium conveyance direction A. In particular, the third medium sensoris located at the downstream side from the second medium sensorin the medium conveyance direction A. The third medium sensorincludes a light emitter and a light receiver provided at one side of the medium conveyance path and a light guide provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light emitter is an LED, etc., and emits light toward the medium conveyance path. The light receiver is a photodiode, etc., and receives light emitted by the light emitter and guided by the light guide. Based on the intensity of the light received by the light receiver, the third medium sensorgenerates and outputs a third medium signal with a signal value changing between the state where there is the medium at the position of the third medium sensorand the state where there is no medium.

The first skew sensorand the second skew sensorare located at a downstream side from the feed rollerand separation rollerand the upstream side from the first conveyance rollerand the first driven rollerin the medium conveyance direction A, and detect a medium. In particular, the first skew sensorand the second skew sensorare located at a downstream side from the third medium sensorin the medium conveyance direction A. The first skew sensorand the second skew sensormay be located at an upstream side from the third medium sensorin the medium conveyance direction A. The first skew sensorand the second skew sensorare located at the same position in the medium conveyance direction Aand aligned spaced apart in the width direction A.

The first skew sensorincludes a light emitter and a light receiver provided at one side of the medium conveyance path and a light guide provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light emitter is an LED, etc., and emits light toward the medium conveyance path. The light receiver is a photodiode, etc., and receives light emitted by the light emitter and guided by the light guide. Based on the intensity of the light received by the light receiver, the first skew sensorgenerates and outputs a first skew signal with a signal value changing between the state where there is the medium at the position of the first skew sensorand the state where there is no medium.

The second skew sensorincludes a light emitter and a light receiver provided at one side of the medium conveyance path and a light guide provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light emitter is an LED, etc., and emits light toward the medium conveyance path. The light receiver is a photodiode, etc., and receives light emitted by the light emitter and guided by the light guide. Based on the intensity of the light received by the light receiver, the second skew sensorgenerates and outputs a second skew signal with a signal value changing between the state where there is the medium at the position of the second skew sensorand the state where there is no medium.

The ultrasonic sensoris located at the downstream side from the feed rollerand separation rollerand the upstream side from the first conveyance rollerand the first driven roller. The ultrasonic sensormay be located at the downstream side from the first conveyance rollerand the first driven roller. The ultrasonic sensorincludes an ultrasonic wave transmitterand ultrasonic wave receiverlocated in the vicinity of the medium conveyance path facing each other with the medium conveyance path therebetween. The ultrasonic wave transmittertransmits an ultrasonic wave. The ultrasonic wave receiverreceives the ultrasonic wave transmitted by the ultrasonic wave transmitterand passing through the medium and generates and outputs an electrical signal corresponding to the received ultrasonic wave as an ultrasonic wave signal. The ultrasonic wave signal indicates the magnitude of the ultrasonic wave passing through the medium being fed.

The first to sixth conveyance rollerstoand the first to sixth driven rollerstoare located facing each other at the downstream side from the feed rollerand separation rollerin the medium conveyance direction A. The first to sixth conveyance rollerstoand the first to sixth driven rollerstoconvey the medium fed by the feed rollerand separation rollertoward the downstream side. The sixth conveyance rollerand sixth driven rollereject the medium to the ejection tray.

The fourth medium sensoris located at the downstream side from the first conveyance rollerand the first driven rollerand the upstream side from the second conveyance rollerand second driven rollersin the medium conveyance direction A, and detects the medium. The fourth medium sensormay be located at the downstream side from the second conveyance rollerand the second driven rollerin the medium conveyance direction Aand the upstream side from the imaging device. The fourth medium sensorincludes a light emitter and a light receiver provided at one side of the medium conveyance path and a light guide provided at a position facing the light emitter and the light receiver with the medium conveyance path therebetween. The light emitter is an LED, etc., and emits light toward the medium conveyance path. The light receiver is a photodiode, etc., and receives light emitted by the light emitter and guided by the light guide. Based on the intensity of the light received by the light receiver, the fourth medium sensorgenerates and outputs a fourth medium signal with a signal value changing between the state where there is the medium at the position of the fourth medium sensorand the state where there is no medium.

Note that, in the second medium sensor, third medium sensor, first skew sensor, second skew sensor, and/or fourth medium sensor, instead of a light guide, a mirror or other reflection member may be used. Further, the light emitter and light receiver may be provided facing each other with the medium conveyance path therebetween. Further, the sensors may detect the presence of a medium by a contact detection sensor, etc., which runs a predetermined current when the medium is contacted or when the medium is not contacted.

The imaging deviceis located at a downstream side from the first and the second conveyance rollersandin the medium conveyance direction Aand captures the medium conveyed by the first and the second conveyance rollersandand the first and second driven rollersand. The imaging deviceincludes a first imaging deviceand second imaging devicelocated facing each other with the medium conveyance path therebetween. The first imaging deviceis provided at the second housing, while the second imaging deviceis provided at the first housing.

The first imaging deviceincludes a line sensor based on a unity-magnification optical system type Contact Image Sensor (CIS) including an imaging element based on a Complementary Metal Oxide Semiconductor (CMOS) linearly located in a main scanning direction. Further, the first imaging deviceincludes a lens for forming an image on the imaging element, and an Analog-to-Digital (A/D) converter for amplifying and analog-digital converting an electric signal output from the imaging element. The first imaging devicecaptures an image of the front surface of the conveyed medium to generate and output an input image.

Similarly, the second imaging deviceincludes a line sensor based on a unity-magnification optical system type CIS including an imaging element based on a CMOS linearly located in a main scanning direction. The second imaging deviceincludes a lens for forming an image on the imaging element, and an A/D converter for amplifying and analog-digital converting an electric signal output from the imaging element.

Note that, the medium feed apparatusmay have only one of the first imaging deviceand the second imaging deviceand read only one surface of the medium. Further, a line sensor based on a unity-magnification optical system type CIS including an imaging element based on Charge Coupled Devices (CCDs) may be used in place of the line sensor based on a unity-magnification optical system type CIS including an imaging element based on a CMOS. Further, a line sensor based on a reduction optical system type line sensor including an imaging element based on CMOS or CCDs may be used.

The medium stacked on the stacking trayis conveyed between the first guideand the second guidetoward the medium conveyance direction Aby the pick rollerand the feed rollerrespectively rotating in the medium feed directions A, A. The medium feed apparatushas a separation mode in which the medium is fed while separating and a nonseparation mode in which the medium is fed without separating as feed modes. The feed mode is set by the user using the operating deviceor an information processing apparatus coupled to the medium feed apparatusto communicate with it. If the feed mode is set to the separation mode, the separation rollerrotates in the direction of the arrow A, i.e., the direction opposite to the medium feed direction, or stops. Therefore, feed of the medium other than the separated medium is restricted (multi-feed is prevented). On the other hand, if the feed mode is set to the nonseparation mode, the separation rollerrotates in the opposite direction to the arrow A, i.e., in the medium feed direction.

The medium is sent to the imaging position of the imaging deviceby being guided by the first guideand the second guidewhile the first and second conveyance rollersandrotate in the directions of the arrows Aand Aand is captured by the imaging device. Furthermore, the medium is ejected onto the ejection trayby the third to the sixth conveyance rollerstorespectively rotating in the directions of the arrows Ato A.

are schematic views for explaining an example of a first arm and an example of a second arm.illustrates a schematic view seen from above of the surroundings of the separation rollerof the first housingin the state with the second housingopened, whileillustrates a schematic view seen from the side of the surroundings of the feed rollerand the separation roller.

As illustrated in, the medium feed apparatushas the first armand second arm. In the example illustrated in, a plurality of separation rollersare located spaced apart in the width direction Aperpendicular to the medium conveyance direction. In this case, a plurality of feed rollersare located spaced apart in the width direction Aperpendicular to the medium conveyance direction to face the separation rollers.

The first armis a plate-shaped member extending along the medium conveyance direction Aand is provided swingably (rotatably) in the height direction Aabout an upstream side end partat the first housing. The first armis located between the plurality of separation rollersin the width direction Aperpendicular to the medium conveyance direction. The first armhas a first projecting part. The first projecting partis provided swingably so as to project out from the first guide, i.e., the guide surface of the medium, and is located at an upstream side from nip parts N of the feed rollersand the separation rollersin the medium conveyance direction Ain the state projecting out from the first guide

The second armis a plate-shaped member extending along the medium conveyance direction Aand is provided swingably (rotatably) in the height direction Aabout an upstream side end part. The second armis located between the plurality of separation rollersin the width direction Aperpendicular to the medium conveyance direction. A gap is provided at the center part of the second armin the width direction A. The first armis located at the center part (gap) of the second armin the width direction A. The second armhas a second projecting part. The second projecting partis provided swingably so as to project out from the first guide, i.e., the guide surface of the medium, and is located so as to overlap the nip parts N of the feed rollersand the separation rollersin the medium conveyance direction Ain the state projecting out from the first guide. In other words, the second projecting partis located at the downstream side from the first projecting partin the medium conveyance direction A.

If the medium is returned from the downstream side toward the upstream side, that medium is subjected to the pressing force from the pick rollerand the feed roller. For this reason, there is a possibility of the medium buckling between the pick rollerand the feed rollerand the possibility of the separation rollerslipping and the medium jamming. As opposed to this, the first projecting partand the second projecting partpush the medium being fed upward at the center of the width direction A. The medium being fed bends in a wavy manner in the width direction A, so the medium feed apparatuscan stiffen the medium and can improve the rigidity of the medium moving along the medium conveyance direction A.

For this reason, even if returning a thin medium with weak stiffness from the downstream side toward the upstream side, the medium feed apparatuscan keep the medium from buckling and jamming. Further, even when a medium includes several sheets of paper such as an envelope or carbon paper are returned from the downstream side toward the upstream side, the medium feed apparatuscan keep the medium from jamming since the medium has stiffened enough to withstand separation force from the separation roller. In particular, the medium feed apparatususes the first projecting partand the second projecting partlocated at mutually different positions in the medium conveyance direction Ato stiffen the medium in two stages. Therefore, the medium has higher stiffness, so the medium feed apparatuscan keep the medium from buckling or jamming.

is a schematic view for explaining an example of a pick roller.