MEDIA CONVEYING APPARATUS, MEDIA FEEDING METHOD, AND NON-TRANSITORY RECORDING MEDIUM

A media conveying apparatus includes a media table, a feed roller to feed a medium placed on the media table, a separation roller located to face the feed roller, a first motor to drive the feed roller, a second motor to drive the separation roller, and circuitry. The circuitry determines whether multi-feed of the medium has occurred and controls the first motor and the second motor such that the feed roller rotates after the separation roller rotates to return the medium to the media table when it is determined that the multi-feed of the medium has occurred.

BACKGROUND

The present disclosure relates to a media conveying apparatus, a media feeding method, and a non-transitory recording medium.

When multi-feed of a medium occurs in a media conveying apparatus such as a scanner that sequentially feeds multiple media while separating the media from each other and images the media, the user needs to remove the media from the inside of a housing and reset the media on a media table.

SUMMARY

According to an embodiment of the present disclosure, a media conveying apparatus includes a media table, a feed roller to feed a medium placed on the media table, a separation roller located to face the feed roller, a first motor to drive the feed roller, a second motor to drive the separation roller, and circuitry. The circuitry determines whether multi-feed of the medium has occurred and controls the first motor and the second motor such that the feed roller rotates after the separation roller rotates to return the medium to the media table when it is determined that the multi-feed of the medium has occurred.

According to an embodiment of the present disclosure, a media feeding method includes feeding a medium placed on a media table by a feed roller; determining whether multi-feed of the medium has occurred; and controlling a first motor to drive the feed roller and a second motor to drive a separation roller located to face the feed roller, such that after temporarily stopping the medium, the feed roller rotates after the separation roller rotates to return the medium to the media table when it is determined that the multi-feed of the medium has occurred.

According to an embodiment of the present disclosure, a non-transitory recording medium stores a plurality of instructions which, when executed by one or more processors, causes the one or more processors to perform a method for controlling a media conveying apparatus. The method includes determining whether multi-feed of the medium has occurred, and controlling a first motor to drive a feed roller and a second motor to drive a separation roller located to face the feed roller, such that after temporarily stopping the medium, the feed roller rotates after the separation roller rotates to return the medium to a media table when it is determined that the multi-feed of the medium has occurred.

DETAILED DESCRIPTION

Referring now to the drawings, embodiments of the present disclosure are described below.

As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “connected/coupled” includes both direct connections and connections in which there are one or more intermediate connecting elements.

For the sake of simplicity, like reference signs denote like elements such as parts and materials having the same functions, and redundant descriptions thereof are omitted unless otherwise required.

The advantages of the present disclosure are recognized and achieved by the elements particularly pointed out in the appended claims and the combinations thereof. It is to be understood that both the above-described general description and the detailed description described below are exemplary and explanatory only and are not intended to restrict the claimed invention.

A description is given below of a media conveying apparatus, a media feeding method, and a control program according to embodiments of the present disclosure, with reference to the drawings. The technical scope of the present disclosure, however, is not limited to the embodiments described below but includes the scope of the appended claims and the equivalents thereof.

FIG.1is a perspective view of a media conveying apparatus100as an image scanner. The media conveying apparatus100conveys and images media being documents. The media are, for example, sheets of plain paper, sheets of thin paper, sheets of thick paper, cards, booklets, or passports. Alternatively, the media conveying apparatus100may be, for example, a facsimile machine, a copier, or a multifunction peripheral (MFP). The media to be conveyed may be, for example, printing material (e.g., paper sheets) instead of documents. In this case, the media conveying apparatus100may be a printer, etc.

The media conveying apparatus100includes a lower housing101, an upper housing102, a media table103, an ejection table104, an operation device105, and a display device106. InFIG.1, arrow A1indicates a media conveyance direction in which media are conveyed. An arrow A2indicates a width direction orthogonal to the media conveyance direction. An arrow A3indicates a height direction orthogonal to a media conveyance passage. In the following description, the media conveyance direction indicated by arrow A1, the width direction indicated by arrow A2, and the height direction indicated by arrow A3may be referred to as a media conveyance direction A1, a width direction A2, and a height direction A3, respectively. In the following description, the term “upstream” refers to upstream in the media conveyance direction A1whereas the term “downstream” refers to downstream in the media conveyance direction A1.

The upper housing102is located at a position covering the upper face of the media conveying apparatus100and is hinged to the lower housing101such that the upper housing102can be opened and closed to, for example, remove a jammed medium or clean the inside of the media conveying apparatus100.

The media table103is engaged with the lower housing101. Media to be fed and conveyed are placed on the media table103. The ejection table104is engaged with the upper housing102and stack ejected media. The ejection table104may be engaged with the lower housing101.

The operation device105includes an input device such as keys and an interface circuit that acquires signals from the input device. The operation device105receives an input operation performed by a user and outputs an operation signal corresponding to the input operation performed by the user. The display device106includes a display and an interface circuit that outputs image data to the display and displays the image data on the display. Examples of the display include, but are not limited to, a liquid crystal and an organic electro-luminescence (EL).

FIG.2is a diagram illustrating a conveyance passage inside the media conveying apparatus100.

The media conveying apparatus100includes a first media sensor111, a restriction guide112, a cam113, a flap114, a feed roller115, a separation roller116, a second media sensor117, an ultrasonic sensor118, a conveyance roller119, a first facing roller120, a third media sensor121, an imaging device122, an ejection roller123, and a second facing roller124along the conveyance passage.

The number of each of the feed roller115, the separation roller116, the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124is not limited to one, and may be two or more. In this case, the two or more rollers of the feed rollers115, the separation rollers116, the conveyance rollers119, the first facing rollers120, the ejection rollers123, and/or the second facing rollers124are aligned and spaced apart in the width direction A2orthogonal to the media conveyance direction A1.

The upper face of the lower housing101forms a lower guide101afor the media conveyance passage. The lower face of the upper housing102forms an upper guide102afor the media conveyance passage.

The first media sensor111is located upstream from the feed roller115and the separation roller116. The first media sensor111includes a contact sensor and detects whether a medium is placed on the media table103. The first media sensor111generates and outputs a first media signal whose signal value changes depending on whether a medium is placed on the media table103. The first media sensor111is not limited to the contact sensor. The first media sensor111may be any other sensor that can detect the presence of a medium, such as an optical sensor.

The feed roller115is located in the lower housing101and sequentially separates and feeds the media on the media table103from the bottom. The separation roller116is a so-called brake roller or retard roller. The separation roller116is located in the upper housing102to face the feed roller115. The separation roller116is stoppable or rotatable in a direction opposite to a media feeding direction. Alternatively, the feed roller115may be located in the upper housing102and the separation roller116may be located in the lower housing101, and the feed roller115may feed the media on the media table103from the top.

The second media sensor117is located downstream from the feed roller115and upstream from the conveyance roller119. The second media sensor117detects the medium conveyed to the position of the second media sensor117. The second media sensor117includes a light emitter, a light receiver, and a light guide. The light emitter and the light receiver are located on one side of the media conveyance passage. The light guide faces the light emitter and the light receiver across the media conveyance passage. The light emitter is, for example, a light emitting diode (LED) and emits light toward the media conveyance passage. By contrast, the light receiver is, for example, a photodiode and receives light that is emitted by the light emitter and guided by the light guide. When a medium faces the second media sensor117, the light emitted from the light emitter is blocked by the medium, and therefore, the light receiver does not detect the light emitted from the light emitter. Based on the intensity of the light received by the light receiver, the second media sensor117generates and outputs a second media signal whose signal value changes depending on whether a medium is present at the position of the second media sensor117.

A reflector such as a mirror may be used instead of the light guide. The light emitter and the light receiver may face each other across the media conveyance passage. The second media sensor117may detect the presence of a medium with, for example, a contact sensor that causes a predetermined current to flow when a medium is in contact with the contact sensor or when no medium is in contact with the contact sensor.

The ultrasonic sensor118is located downstream from the feed roller115, particularly from the second media sensor117, and upstream from the conveyance roller119. The ultrasonic sensor118includes an ultrasonic transmitter118aand an ultrasonic receiver118b. The ultrasonic transmitter118aand the ultrasonic receiver118bare located near the media conveyance passage and face each other across the media conveyance passage. The ultrasonic transmitter118atransmits ultrasonic waves. The ultrasonic receiver118breceives the ultrasonic waves having been transmitted by the ultrasonic transmitter118aand have penetrated a medium. The ultrasonic receiver118bgenerates and outputs an ultrasonic signal which is an electrical signal corresponding to the received ultrasonic waves. When multiple media are conveyed in overlapped state, the ultrasonic waves penetrating the media are attenuated by an air layer between the media conveyed in overlapped state. Accordingly, the media conveying apparatus100can detect the multi-feed of the medium based on the ultrasonic signal.

The conveyance roller119and the first facing roller120are located downstream from the feed roller115and the separation roller116in the media conveyance direction A1and face each other. The conveyance roller119is located in the upper housing102and conveys the medium fed by the feed roller115and the separation roller116to the imaging device122. Alternatively, the conveyance roller119may be located in the lower housing101and the first facing roller120may be located in the upper housing102.

The third media sensor121is located downstream from the conveyance roller119and upstream from the imaging device122. The third media sensor121detects the medium conveyed to the position of the third media sensor121. The third media sensor121includes a light emitter, a light receiver, and a light guide. The light emitter and the light receiver are located on one side of the media conveyance passage. The light guide faces the light emitter and the light receiver across the media conveyance passage. The light emitter is, for example, an LED and emits light toward the media conveyance passage. The light receiver is, for example, a photodiode and receives light that is 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 media sensor121generates and outputs a third media signal whose signal value changes depending on whether a medium is present at the position of the third media sensor121.

A reflector such as a mirror may be used instead of the light guide. The light emitter and the light receiver may face each other across the media conveyance passage. The third media sensor121may detect the presence of a medium with, for example, a contact sensor that causes a predetermined current to flow when a medium is in contact with the contact sensor or when no medium is in contact with the contact sensor.

The imaging device122is located downstream from the conveyance roller119and the first facing roller120in the media conveyance direction A1and images the medium conveyed by the conveyance roller119and the first facing roller120. The imaging device122includes a first imaging device122aand a second imaging device122bfacing each other across the media conveyance passage.

The first imaging device122aincludes a line sensor based on a unity-magnification optical system type contact image sensor (CIS) including complementary metal oxide semiconductor-(CMOS-) based imaging elements linearly arranged in a main scanning direction. The first imaging device122afurther includes lenses each forming an image on an imaging element, and an analog-to-digital (A/D) converter amplifying and converting an electric signal output from the imaging element. The first imaging device122agenerates an input image by imaging the front side of a conveyed medium in accordance with control from a processing circuit to be described later and outputs the generated image.

Similarly, the second imaging device122bincludes a line sensor based on a unity-magnification optical system type CIS including CMOS-based imaging elements linearly arranged in the main scanning direction. The second imaging device122bfurther includes lenses each forming an image on an imaging element, and an A/D converter amplifying and analog-digital (A/D) converting an electric signal output from the imaging element. The second imaging device122bgenerates an input image by imaging the back side of a conveyed medium in accordance with control from the processing circuit to be described later and outputs the generated image.

The media conveying apparatus100may include either the first imaging device122aor the second imaging device122band reads only one side of the medium. Further, a line sensor based on a unity-magnification optical system type CIS including charge coupled device-(CCD-) based imaging elements may be used in place of the line sensor based on a unity-magnification optical system type CIS including CMOS-based imaging elements. Further, a reduction optical system type line sensor including CMOS-based or CCD-based imaging elements may be used.

The ejection roller123and the second facing roller124are located downstream from the imaging device122, that is, the conveyance roller119and the first facing roller120in the media conveyance direction A1and face each other. The ejection roller123is located in the upper housing102. The ejection roller123conveys the medium conveyed by the conveyance roller119and the first facing roller120further downstream and ejects the medium to the ejection table104. Alternatively, the ejection roller123may be located in the lower housing101and the second facing roller124may be located in the upper housing102.

As the feed roller115rotates in the media feeding direction indicated by arrow A4, the medium is conveyed from the media table103in the media conveyance direction A1between the lower guide101aand the upper guide102a. The media conveying apparatus100has two feeding modes: a separation mode in which media are fed while being separated and a non-separation mode in which media are fed without being separated. The feeding mode is set by a user using the operation device105or an information processing device communicably connected to the media conveying apparatus100. When the feeding mode is set to the separation mode, the separation roller116stops or rotates in the direction indicated by arrow A5opposite to the media feeding direction. Due to the operations of the feed roller115and separation roller116, only the medium in contact with the feed roller115among the multiple media placed on the media table103is separated. This prevents the feeding of a medium other than the separated medium. In other words, the multi-feed is prevented. By contrast, when the feeding mode is set to the non-separation mode, the separation roller116rotates in the media feeding direction opposite to the direction indicated by arrow A5.

The medium is fed between the conveyance roller119and the first facing roller120while being guided by the lower guide101aand the upper guide102a. As the conveyance roller119and the first facing roller120rotate in the directions indicated by arrows A6and A7, respectively, the medium is fed between the first imaging device122aand the second imaging device122b. As the ejection roller123and the second facing roller124rotate in the directions indicated by arrows A8and A9, respectively, the medium read by the imaging device122is ejected to the ejection table104.

As illustrated inFIG.2, the media conveying apparatus100includes a first motor131, a second motor132, and a third motor133as driving sources of the rollers described above.

The first motor131is located in the lower housing101. The first motor131is coupled to the feed roller115via a first transmission assembly131aand drives the feed roller115. The first motor131generates a driving force for driving the feed roller115according to control signals from the processing circuit. The first transmission assembly131aincludes one or more pulleys, belts, and gears between the first motor131and a shaft115aserving as a rotary shaft of the feed roller115. The first transmission assembly131atransmits the driving force generated by the first motor131to the feed roller115. With this configuration, the first motor131rotates the feed roller115to feed media. Alternatively, the first motor131may be located in the upper housing102.

The second motor132is located in the upper housing102separately from the first motor131. The second motor132is coupled to the separation roller116via a second transmission assembly132aand drives the separation roller116. The second motor132generates a driving force for driving the separation roller116according to control signals from the processing circuit. The second transmission assembly132aincludes one or more pulleys, belts, and gears between the second motor132and a shaft116aserving as a rotary shaft of the separation roller116. The second transmission assembly132atransmits the driving force generated by the second motor132to the separation roller116. With this configuration, the second motor132rotates the separation roller116and causes the separation roller116to separate, feed, and convey media. Alternatively, the second motor132may be located in the lower housing101.

The third motor133is located in the upper housing102separately from the first motor131and the second motor132. The third motor133is coupled to the conveyance roller119, the ejection roller123, and the cam113via a third transmission assembly133aand drives the conveyance roller119, the ejection roller123, and the cam113. The third motor133generates a driving force for driving the conveyance roller119, the ejection roller123, and the cam113according to control signals from the processing circuit. The third transmission assembly133aincludes one or more pulleys, belts, and gears between the third motor133, a shaft119aserving as a rotary shaft of the conveyance roller119, a shaft123aserving as a rotary shaft of the ejection roller123, and a rotary shaft113aof the cam113. The third transmission assembly133atransmits the driving force generated by the third motor133to the conveyance roller119, the ejection roller123, and the cam113. With this configuration, the third motor133rotates the conveyance roller119and the ejection roller123and causes the conveyance roller119and the ejection roller123to convey and eject media. In other words, the conveyance roller119and the ejection roller123are driven by the third motor133. The third motor133rotates the cam113to move the restriction guide112in contact with the cam113. Alternatively, the third motor133may be located in the lower housing101.

As described above, the media conveying apparatus100includes the common motor to drive the conveyance roller119and the ejection roller123and to move the restriction guide112. Accordingly, the media conveying apparatus100can reduce the number of motors and reduce the cost and weight of the media conveying apparatus100.

The first facing roller120is a driven roller that is rotated by the rotation of the conveyance roller119. The second facing roller124is a driven roller that is rotated by the rotation of the ejection roller123. Alternatively, the first facing roller120and/or the second facing roller124may be driven by the driving force from the third motor133.

In this case, one or more gears are further located between the shaft119aof the conveyance roller119and a shaft120aserving as a rotary shaft of the first facing roller120and/or between the shaft123aof the ejection roller123and a shaft124aserving as a rotary shaft of the second facing roller124, and the third transmission assembly133afurther transmits the driving force generated by the third motor133to the first facing roller120and/or the second facing roller124.

FIG.3is a schematic diagram illustrating the restriction guide112, the cam113, and the flap114. Specifically,FIG.3is a side view of the restriction guide112, the cam113, and the flap114before media are fed.

As illustrated inFIG.3, the restriction guide112is a guide for setting media (group) M1placed on the media table103. The restriction guide112is positioned to face the feed roller115and the separation roller116in the media conveyance direction A1. The restriction guide112is rotatably (swingably) supported by the lower housing101and supports the lower face of the media M1placed on the media table103when the media M1are not fed. In the following description, as illustrated inFIG.3, the position at which the restriction guide112supports the lower face of the media M1placed on the media table103may be referred to as a set position.

The cam113is a moving member for moving the restriction guide112. The cam113is located downstream from the restriction guide112in the media conveyance direction A1. The cam113is rotatable (swingable) by the third motor133. The cam113is supported by the lower housing101to be rotatable by the driving force from the third motor133. When media are not fed, the cam113contacts a downstream end of the restriction guide112to hold the restriction guide112at the set position.

The flap114is a stopper for preventing the media M1from entering the nip between the feed roller115and the separation roller116before the media are fed. The flap114is positioned to face the restriction guide112in the media conveyance direction A1. The flap114is swingably located in upper housing102. When the media M1are not fed, the flap114is engaged with the restriction guide112at the set position and prevents the media M1from entering the nip between feed roller115and separation roller116.

In other words, the restriction guide112restricts the contact of the media M1with the feed roller115and the separation roller116at the set position. The set position is an example of a first position.

FIG.4is a schematic diagram illustrating the movement of the restriction guide112, the cam113, and the flap114. Specifically,FIG.4is a side view of the restriction guide112, the cam113, and the flap114when the media are fed.

As illustrated inFIG.4, when the media M1are fed, the cam113swings (rotates) downward (in the direction indicated by arrow A11) by the driving force from the third motor133and is separated from the downstream end of the restriction guide112. When the downstream end of the restriction guide112is separated from the cam113and is not held by the cam113, the restriction guide112swings downward (in the direction indicated by arrow A12) from the media conveyance face and is separated from the lower face of the media M1placed on the media table103. In the following description, as illustrated inFIG.4, the position at which the restriction guide112is separated from the lower face of the media M1placed on the media table103may be referred to as a released position. When the restriction guide112is at the released position, the engagement between the flap114and the restriction guide112is released. As a result, the flap114is pushed by the leading end of the media M1placed on the media table103and swings downstream (in the direction indicated by arrow A13), allowing the media M1to enter the nip between the feed roller115and the separation roller116. As described above, when the restriction guide112is at the released position, the flap114allows the media M1to enter the nip between the feed roller115and the separation roller116.

In other words, the restriction guide112does not restrict the contact of the media M1with the feed roller115and the separation roller116at the released position. The released position is an example of a second position. The restriction guide112is movable between the set position and the released position. The restriction guide112is moved by the rotation of the cam113.

As illustrated inFIGS.3and4, the feed roller115is provided with an outer circumferential surface115b, a one-way clutch115c, etc. The one-way clutch115cis located on the shaft115aserving as the rotary shaft of the feed roller115. The one-way clutch115cprevents (the outer circumferential surface115bof) the feed roller115from rotating about the shaft115ain the direction opposite to the media feeding direction indicated by arrow A4. This prevents the feed roller115from rotating in the direction opposite to the media feeding direction indicated by arrow A4as a result of being dragged by the separation roller116rotating in the direction indicated by arrow A5opposite to the media feeding direction.

The conveyance roller119conveys media at a speed higher than the speed at which the feed roller115feeds media. Therefore, when a medium reaches the position of the conveyance roller119, the medium is pulled by the conveyance roller119while being sandwiched between the feed roller115and the separation roller116. At this time, the outer circumferential surface115bof the feed roller115is rotated by the sandwiched medium due to the operation of the one-way clutch115cand does not hinder the conveyance of media. Alternatively, the conveyance roller119may convey the medium at the same speed as the speed at which the feed roller115feeds the medium.

The separation roller116is provided with, an outer circumferential surface116b, a torque limiter116c, etc. The torque limiter116cis located on a shaft116aserving as a rotary shaft of the separation roller116. The torque limiter116cdefines the maximum torque applied to the separation roller116. The limit value of the torque limiter116cis set to prevent the rotational force from being transmitted through the torque limiter116cwhen a single medium is conveyed, and to transmit the rotational force through the torque limiter116cwhen multiple media are conveyed. As a result, when a single medium is conveyed, the separation roller116is rotated by the rotation of the feed roller115, without being rotated by the driving force from the second motor132. By contrast, when multiple media are conveyed, the separation roller116rotates in the direction indicated by arrow A5opposite to the media feeding direction and separates the medium in contact with the feed roller115from the other media to prevent the occurrence of multi-feed. When the separation roller116is stoppable type and multiple media are conveyed, the outer circumferential surface116bof the separation roller116that is stopped without rotating in the direction indicated by arrow A5opposite to the media feeding direction may apply a force in the direction indicated by arrow A5opposite to the media feeding direction to the media.

FIG.5is a schematic diagram illustrating a container134.

As illustrated inFIG.5, the lower housing101is provided with the container134. The container134contains dust such as paper dust or waste adhering to the media conveyed or deposited to the feed roller115or the separation roller116from the media conveyed. The lower guide101a, which is a media-guiding face of the lower housing101, has an opening101bfor locating the feed roller115. The container134is provided below the feed roller115to face the opening101b. The container134contains the dust that has fallen from the conveyed media, the feed roller115, or the separation roller116and entered from the clearance between the feed roller115and the opening101b. The container134is detachable from the lower housing101, that is, from the media conveying apparatus100. The container134allows the media conveying apparatus100to appropriately collect paper dust or waste and prevent accumulation of paper dust or waste in the media conveyance passage.

FIG.6is a schematic block diagram illustrating a configuration of the media conveying apparatus100.

The media conveying apparatus100further includes an interface device135, a storage device140, and a processing circuit150, in addition to the configuration described above.

The interface device135includes an interface circuit in compliance with a serial bus such as a universal serial bus (USB) and is electrically connected to an information processing device (for example, a personal computer or a mobile information processing terminal) to transmit and receive an input image and various kinds of information to and from the information processing device. The interface device135may be substituted by a communication unit including an antenna to transmit and receive wireless signals and a wireless communication interface device to transmit and receive the signals through a wireless communication line according to a predetermined communication protocol. The predetermined communication protocol is, for example, a wireless local area network (LAN) communication protocol. The communication unit may include a wired communication interface device to transmit and receive signals through a wired communication line according to, for example, a wired LAN communication protocol.

The storage device140includes memories such as a random-access memory (RAM) and a read-only memory (ROM); a fixed disk device such as a hard disk; or a portable memory such as a flexible disk or an optical disk. The storage device140stores, for example, computer programs, databases, and tables used for various processes performed by the media conveying apparatus100. The computer programs may be installed in the storage device140from a computer-readable portable recording medium using, for example, a known setup program. The portable recording medium is, for example, a compact disc read-only memory (CD-ROM) or a digital versatile disc read-only memory (DVD-ROM).

The processing circuit150operates according to a program prestored in the storage device140. The processing circuit150is, for example, a central processing unit (CPU). Alternatively, a digital signal processor (DSP), a large-scale integration (LSI), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc. may be used as the processing circuit150.

The processing circuit150is connected to the operation device105, the display device106, the first media sensor111, the second media sensor117, the ultrasonic sensor118, the third media sensor121, the imaging device122, the first motor131, the second motor132, the third motor133, the interface device135, the storage device140, etc. and controls these components. The processing circuit150controls the driving of the motors described above and the imaging by the imaging device122, according to the media signals received from the media sensors described above. The processing circuit150acquires an input image from the imaging device122and transmits the input image to the information processing device via the interface device135. The processing circuit150determines whether the multi-feed of the medium has occurred based on the ultrasonic signal received from the ultrasonic sensor118. The processing circuit150controls the motors to return the media to the media table103when it is determined that the multi-feed of the medium has occurred.

FIG.7is a schematic block diagram illustrating a configuration of the storage device140and the processing circuit150.

As illustrated inFIG.7, the storage device140stores, a control program141, a determination program142, etc. These programs are functional modules implemented by software operating on the processor. The processing circuit150reads the programs from the storage device140and operates according to the read programs. Thus, the processing circuit150functions as a control unit151and a determination unit152.

FIG.8is a flowchart of a media reading process performed by the media conveying apparatus100.FIG.9is a continuation of the flowchart ofFIG.8.

A description is given below of the media reading process performed by the media conveying apparatus100, with reference to the flowchart ofFIGS.8and9. The sequence of operations described below is executed, for example, by the processing circuit150in cooperation with the components of the media conveying apparatus100based on the program prestored in the storage device140.

In step S101, the control unit151waits until the control unit151receives an operation signal instructing the reading of media from the operation device105or the interface device135. The operation signal is output when the user inputs an instruction to read media using the operation device105or the information processing device.

In step S102, the control unit151acquires the first media signal from the first media sensor111and determines whether a medium is placed on the media table103based on the acquired first media signal. When no medium is placed on the media table103(NO in step S102), the control unit151ends the series of steps.

By contrast, when a medium is placed on the media table103(YES in step S102), in step S103, the control unit151drives the third motor133first. The control unit151drives the third motor133to rotate the cam113in the direction indicated by arrow A11inFIG.3to move the restriction guide112in the direction indicated by arrow A12inFIG.3, that is, from the set position to the released position. The control unit151drives the third motor133to rotate the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124in the directions indicated by arrows A6, A7, A8, and/or A9, respectively, inFIG.2.

In step S104, the control unit151drives the second motor132to rotate the separation roller116in the direction opposite to the feeding direction, that is, in the direction indicated by arrow A5inFIG.2.

In step S105, the control unit151drives the first motor131to rotate the feed roller115in the media feed direction, that is, in the direction indicated by arrow A4inFIG.2, to feed the medium.

FIG.10is a graph illustrating changes in the speed of the feed roller115, the separation roller116, and the conveyance roller119.

InFIG.10, a graph G11indicates a change in the speed of the feed roller115, a graph G12indicates a change in the speed of the separation roller116, and a graph G13indicates a change in the speed of the conveyance roller119. Since the speeds of the first facing roller120, the ejection roller123, and the second facing roller124change like the speed of the conveyance roller119, the change in the speed of the conveyance roller119will be described below as a representative example. The horizontal axis of each of the graphs G11to G13indicates time, whereas the vertical axis of each of the graphs G11to G13indicates speed.

A graph G14indicates a change in the signal value of the second media sensor117, whereas a graph G15indicates a change in the signal value of the third media sensor121. The horizontal axis of each of the graphs G14and G15indicates time, whereas the vertical axis of each of the graphs G14and G15indicates signal value. In the present embodiment, when no medium is present at the position of each sensor, the signal value of the corresponding signal indicates L. By contrast, when a medium is present at the position of each sensor, the signal value of the corresponding signal indicates H.

InFIG.10, time T1indicates the time to start feeding media. As described above, the control unit151starts driving the third motor133, the second motor132, and the first motor131in this order. Therefore, the conveyance roller119, the separation roller116, and the feed roller115sequentially start rotating at the times T1, T2, and T3, respectively. The speed V2of the separation roller116(the moving speed of the outer circumferential surface of the separation roller116) is set to be lower than the speed V1of the feed roller115(the moving speed of the outer circumferential surface of the feed roller115). The speed V3of the conveyance roller119(the moving speed of the outer circumferential surface of the conveyance roller119) is set to be higher than the speed V1of the feed roller115(the moving speed of the outer circumferential surface of the feed roller115).

The control unit151starts driving the third motor133, the second motor132, and the first motor131in this order. Therefore, when the restriction guide112moves from the set position and releases the medium from the restriction by the flap114, that is, when the leading end of the media placed on the media table103contacts the separation roller116and the feed roller115, the feed roller115and the separation roller116have been stopped. Then, the separation roller116starts rotating before the feed roller115starts rotating. Thus, as illustrated inFIG.4, the media group M1placed on the media table103contacts the separation roller116before entering the nip between the feed roller115and the separation roller116. The separation roller116rotating in the direction opposite to the media feeding direction separates the leading ends of the media group M1so that upper media are upstream from the lower media of the media group M1. This prevents multiple media from entering the nip between the feed roller115and the separation roller116when the feed roller115starts rotating, thus preventing the occurrence of multi-feed of the medium.

Since the separation roller116starts rotating before the feed roller115starts rotating, the separation roller116is prevented from being rotated by the rotation of the feed roller115before the separation roller116starts rotating, and thus the separation roller116can favorably separate the media.

Alternatively, the control unit151may execute the operation in step S104before the operation in step S103to operate the second motor132and then operate the third motor133at the start of feeding of media. In this case, when the restriction guide112moves from the set position and the leading end of the media contacts the separation roller116and the feed roller115, the separation roller116rotates while the feed roller115is stopped. Therefore, in this case, the media conveying apparatus100controls the first motor131, the second motor132, and the third motor133to rotate the feed roller115after the separation roller116in rotating state contacts the media. The separation roller116rotating in the direction opposite to the media feeding direction separates the leading ends of the media group M1so that upper media are upstream from the lower media of the media group M1. This prevents multiple media from entering the nip between the feed roller115and the separation roller116together when the feed roller115starts rotating, thus preventing the occurrence of multi-feed of the medium.

Since the separation roller116starts rotating before the feed roller115starts rotating, the separation roller116is prevented from being rotated by the rotation of the feed roller115before the separation roller116starts rotating, and thus the separation roller116can favorably separate the media.

As described above, at the start of feeding of media, the control unit151controls the first motor131, the second motor132, and the third motor133to rotate the feed roller115after the separation roller116in rotating state contacts the media. In particular, at the start of feeding of media, the control unit151operates the second motor132and the third motor133and then operates the first motor131. Accordingly, the control unit151can prevent the occurrence of multi-feed of the medium at the start of feeding of media.

As described above, the restriction guide112is moved by the rotation of the cam113. The restriction guide112and the flap114are engaged with each other to restrict the contact of the media with the feed roller115and the separation roller116. Therefore, it takes some time from when the third motor133is driven to when the restriction guide112and the flap114move and the media contact the feed roller115and the separation roller116. The control unit151can shorten the time taken to feed the media by driving the third motor133to start the movement of the restriction guide112and the flap114before driving the first motor131to start the rotation of the feed roller115.

The control unit151may wait for a first predetermined time from when the control unit151drives the third motor133in step S103to when the control unit151drives the first motor131in step S105. The first predetermined time is set to a time from when the third motor133is driven to when the leading ends of the media restricted by the flap114contact the separation roller116rotating in the direction opposite to the media feeding direction. This ensures that the separation force is applied from the separation roller116to the media group before the feeding force is applied from the feed roller115. Accordingly, the control unit151can reliably prevent the occurrence of the multi-feed of the medium.

As described above, the shaft116aof the separation roller116is provided with the torque limiter116c. Depending on the position of the torque limiter116c, a clearance (backlash) may be present between the shaft116aand the outer circumferential surface116bof the separation roller116, where the driving force is not transmitted. Therefore, depending on the position of the torque limiter116c, it may take some time until the driving force is transmitted from the second motor132to the separation roller116. The control unit151can remove the clearance (backlash) between the shaft116aand the separation roller116by driving the second motor132to start the rotation of the separation roller116before driving the first motor131to start the rotation of the feed roller115. This ensures that the separation force is applied from the separation roller116to the media group before the feeding force is applied from the feed roller115. Accordingly, the control unit151can prevent the occurrence of the multi-feed of the medium.

The control unit151may wait for a second predetermined time from when the control unit151drives the second motor132in step S104to when the control unit151drives the first motor131in step S105. The second predetermined time is set to a time from when the second motor132is driven to when the separation roller116is reliably rotated. Accordingly, the control unit151can reliably prevent the occurrence of multi-feed of the medium.

Referring back toFIG.8, in step S106, the control unit151waits until the leading end of the conveyed medium passes the position of the second media sensor117. The control unit151periodically acquires the second media signal from the second media sensor117and determines that the leading end of the medium has passed the position of the second media sensor117when the signal value of the second media signal changes from a value indicating the absence of a medium to a value indicating the presence of a medium.

In step S107, the control unit151controls the second motor132to stop the separation roller116.

InFIG.10, time T4indicates the time when the signal value of the second media signal changes from L to H, that is, the time when the leading end of the medium passes the position of the second media sensor117. As illustrated inFIG.10, when the leading end of the medium passes the position of the second media sensor117, the rotation of the separation roller116is stopped. When the leading end of the medium passes the position of the second media sensor117, the leading end of the medium has already passed through the nip between the feed roller115and the separation roller116. In short, the separation of the medium has been completed. Accordingly, by stopping the separation roller116, the control unit151can reduce the power consumption and the temperature of the media conveying apparatus100while separating the medium as appropriate.

Referring back toFIG.8, in step S108, the control unit151waits until the leading end of the conveyed medium passes the position of the conveyance roller119. The control unit151periodically acquires the third media signal from the third media sensor121and determines that the leading end of the medium has passed the position of the third media sensor121when the signal value of the third media signal changes from a value indicating the absence of a medium to a value indicating the presence of a medium. The control unit151determines that the leading end of the medium has passed the position of the conveyance roller119when the leading end of the medium has passed the position of the third media sensor121.

In step S109, the control unit151controls the first motor131to stop the feed roller115.

InFIG.10, time T5indicates the time when the signal value of the third media signal changes from L to H, that is, the time when the leading end of the medium passes the position of the third media sensor121. As illustrated inFIG.10, after the leading end of the medium passes the position of the third media sensor121, the control unit151stops the feed roller115. As a result, the medium is thereafter conveyed by the conveyance roller119, whereas the feed roller115is rotated by the medium being conveyed. By stopping the feed roller115, the control unit151can prevent the medium from being jammed due to the medium being pushed by the feed roller115and bent between the feed roller115and the conveyance roller119.

Referring back toFIG.8, in step S110, the control unit151causes the imaging device122to start imaging the medium.

In step S111, the control unit151waits until the trailing end of the conveyed medium passes the position of the second media sensor117. The control unit151periodically acquires the second media signal from the second media sensor117and determines that the trailing end of the medium has passed the position of the second media sensor117when the signal value of the second media signal changes from a value indicating the presence of a medium to a value indicating the absence of a medium.

In step S112, the control unit151determines whether a medium remains on the media table103based on the first media signal received from the first media sensor111.

When a medium remains on the media table103(YES in step S112), in step S113, the control unit151controls the second motor132to rotate the separation roller116again in the direction opposite to the media feeding direction, that is, in the direction indicated by arrow A5inFIG.2.

In step S114, the control unit151controls the first motor131to rotate the feed roller115again in the media feeding direction, that is, in the direction indicated by arrow A4inFIG.2, to feed the following medium.

InFIG.10, time T6indicates the time when the signal value of the second media signal changes from H to L, that is, the time when the trailing end of the medium passes the position of the second media sensor117. As described above, the control unit151starts driving the second motor132and the first motor131in this order. Therefore, the separation roller116and the feed roller115sequentially start rotating at the times T6and T7, respectively.

Thus, the control unit151can cause the separation roller116to apply the separation force to the media group remaining on the media table103before the feeding force is applied by the feed roller115. As a result, before the leading ends of the media group remaining on the media table103enter the nip between the feed roller115and the separation roller116, the separation roller116rotating in the direction opposite to the media feeding direction separates the leading ends of the media group so that the upper media are upstream from the lower media of the media group. This prevents multiple media from entering the nip between the feed roller115and the separation roller116when the feed roller115starts rotating, thus preventing the occurrence of multi-feed of the medium.

Since the separation roller116starts rotating before the feed roller115starts rotating, the separation roller116is prevented from being rotated by the rotation of the feed roller115before the separation roller116starts rotating, and thus the separation roller116can favorably separate the media.

As described above, at the start of feeding of the second and following media of the media set on the restriction guide112, the control unit151controls the first motor131and the second motor132to rotate the separation roller116and then rotate the feed roller115. Accordingly, the control unit151can prevent the occurrence of multi-feed of the medium at the start of feeding of the second and following media.

Referring back toFIG.9, in step S115, the control unit151waits until the trailing end of the preceding medium passes through the imaging position in the imaging device122. The control unit151periodically acquires the third media signal from the third media sensor121and determines that the trailing end of the preceding medium has passed the position of the third media sensor121when the signal value of the third media signal changes from a value indicating the presence of a medium to a value indicating the absence of a medium. The control unit151determines that the trailing end of the preceding medium has passed through the imaging position when a third predetermined time has elapsed since the trailing end of the preceding medium has passed the position of the third media sensor121. The third predetermined time is set to a value obtained by adding a margin to the time taken for media to move from the position of the third media sensor121to the imaging position.

In step S116, the control unit151acquires an input image from the imaging device122and transmits (i.e., outputs) the acquired input image to the information processing device via the interface device135.

The control unit151then returns to step S106and repeats the operations from step S106onward for the following medium. In this case, in step S106, the control unit151waits until the leading end of the following medium passes the position of the second media sensor117(at the time T8inFIG.10). In step S107, the control unit151controls the second motor132to stop the separation roller116. In step S108, the control unit151waits until the leading end of the following medium passes the position of the conveyance roller119(at the time T9inFIG.10). In step S109, the control unit151controls the first motor131to stop the feed roller115.

By contrast, when no medium remains on the media table103(NO in step S112), in step S117, the control unit151waits until the trailing end of the conveyed medium passes through the imaging position in the imaging device122as in the operation in step S115.

In step S118, the control unit151acquires an input image from the imaging device122and transmits (i.e., outputs) the acquired input image to the information processing device via the interface device135.

In step S119, the control unit151waits until the trailing end of the conveyed medium passes the position of the ejection roller123. The control unit151determines that the trailing end of the medium has passed the position of the ejection roller123when a fourth predetermined time has elapsed since the trailing end of the medium has passed the position of the third media sensor121. The fourth predetermined time is set to a value obtained by adding a margin to the time taken for media to move from the position of the third media sensor121to the position of the ejection roller123.

In step S120, the control unit151controls the third motor133to stop the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124.

In step S121, the control unit151controls the third motor133to rotate the cam113in the direction opposite to the direction indicated by arrow A11inFIG.3to move the restriction guide112in the direction opposite to the direction indicated by arrow A12inFIG.3, that is, from the released position to the set position. As a result, the restriction guide112is located at the set position, and the flap114is engaged with the restriction guide112at the set position and located at a position (illustrated inFIG.3) to prevent the media from entering the nip between the feed roller115and the separation roller116. At this time, the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124rotate in the directions opposite to the directions indicated by arrows A6, A7, A8, and A9, respectively, inFIG.2. However, no problem occurs because no medium is present in the media conveyance passage.

In step S122, the control unit151controls the third motor133to stop the cam113.

In step S123, the control unit151controls the first motor131or the second motor132to rotate the feed roller115or the separation roller116. The control unit151controls the first motor131or the second motor132to rotate one or both of the feed roller115and the separation roller116in the media feeding direction. By rotating one of the feed roller115and the separation roller116, the control unit151can cause the other roller to be rotated by the rotation of the one of the feed roller115and the separation roller116.

In other words, when no medium is fed, the control unit151controls the first motor131or the second motor132to rotate the feed roller115or the separation roller116while the restriction guide112is located at the set position. The control unit151rotates the feed roller115or the separation roller116to move the dust adhering to the feed roller115or the separation roller116. As the feed roller115and the separation roller116rotate, the dust adhering to the feed roller115or the separation roller116from the fed medium falls from the feed roller115or the separation roller116and is contained in the container134. Further, the rotation of the feed roller115and the separation roller116diffuses the dust adhering to the rollers or the dust aggregated around the rollers. Accordingly, the contact area between the medium and the rubber portion of each roller is secured, allowing the media conveying apparatus100to prevent a decrease in the forces for feeding and separating media.

In step S124, the control unit151controls the first motor131or the second motor132to stop the feed roller115or the separation roller116. Thus, the control unit151ends the series of steps.

The operations in steps S103, S104, and S105may be executed in any order. The operations in steps S113and S114may be executed in any order. The operations in steps S123and S124may be executed at any time when no medium is fed. Alternatively, the operations in steps S123and S124may be omitted.

FIG.11is a flowchart of a multi-feed determination process performed by the media conveying apparatus100.

A description is given below of the multi-feed determination process performed by the media conveying apparatus100, with reference to the flowchart ofFIG.11. The sequence of operations described below is executed, for example, by the processing circuit150in cooperation with the components of the media conveying apparatus100based on the program prestored in the storage device140. The sequence of operations illustrated inFIG.11is periodically executed during conveyance of media.

In step S201, the determination unit152acquires the ultrasonic signal from the ultrasonic sensor118.

In step S202, the determination unit152determines whether the multi-feed of the medium has occurred based on the acquired ultrasonic signal. When the signal value of the ultrasonic signal is equal to or greater than a multi-feed threshold, the determination unit152determines that the multi-feed of the medium has not occurred. By contrast, when the signal value of the ultrasonic signal is less than the multi-feed threshold, the determination unit152determines that the multi-feed of the medium has occurred. The multi-feed threshold is set to a value between the signal value of the ultrasonic signal when a single sheet is conveyed and the signal value of the ultrasonic signal when the multi-feed of sheets occurs. When the determination unit152determines that the multi-feed of the medium has not occurred (NO in step S202), the determination unit152returns to step S201and repeats the operations in steps S201to S202.

By contrast, when the determination unit152determines that the multi-feed of the medium has occurred (YES in step S202), in step S203, the control unit151temporarily stops the media reading process.

In step S204, the control unit151controls the first motor131and the second motor132to stop the feed roller115and the separation roller116. The determination unit152determines that the multi-feed of the medium has occurred when the leading ends of the multi-fed media pass the position of the ultrasonic sensor118. At this time, the leading ends of the media have not reached the position of the conveyance roller119. The control unit151controls the third motor133to continue to rotate the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124. Accordingly, the control unit151can continue to convey the medium that has been fed before the multi-fed media.

In step S205, the control unit151controls the second motor132to rotate the separation roller116again in the direction opposite to the media feeding direction, that is, in the direction indicated by arrow A5inFIG.2.

In step S206, the control unit151controls (reverses) the first motor131to rotate the feed roller115in the direction opposite to the media feeding direction, that is, in the direction opposite to the direction indicated by arrow A4inFIG.2, to return the multi-fed media to the media table103. The control unit151controls the first motor131and the second motor132to set the circumferential speed of the shaft115aserving as the rotary shaft of the feed roller115to be higher than the circumferential speed of the outer circumferential surface115bof the feed roller115that is rotated by the rotation of the separation roller116.

In this way, when the determination unit152determines that the multi-feed of the medium has occurred, the control unit151controls the first motor131and the second motor132to return the media to the media table103. When returning the media to the media table103, the control unit151controls the first motor131and the second motor132to rotate the separation roller116and then rotate the feed roller115. When returning the media to the media table103, the control unit151controls the first motor131and the second motor132to set the circumferential speed of the shaft115aserving as the rotary shaft of the feed roller115to be higher than the circumferential speed of the outer circumferential surface115bof the feed roller115that is rotated by the rotation of the separation roller116.

FIG.12is a schematic diagram illustrating the operation of returning media M2, which have been multi-fed, to the media table103. Specifically,FIG.12is a side view of the feed roller115and the separation roller116when the multi-feed occurs.

As described above, the limit value of the torque limiter116clocated on the shaft116aof the separation roller116is set to transmit the rotational force through the torque limiter116cwhen multiple media are conveyed. When the shaft115aserving as the rotary shaft of the feed roller115is rotated in the direction indicated by arrow A21opposite to the media feeding direction, the outer circumferential surface115bof the feed roller115is not rotated by the driving force from the first motor131due to the operation of the one-way clutch115c. The outer circumferential surface115bof the feed roller115is rotated in the direction indicated by arrow A22opposite to the media feeding direction by the rotation of the separation roller116.

The shaft115aof the feed roller115rotates at a circumferential speed higher than the circumferential speed of the outer circumferential surface115bof the feed roller115that is rotated by the rotation of the separation roller116. Thus, the outer circumferential surface115bof the feed roller115is rotated by the rotation of the outer circumferential surface116bof the separation roller116without being hindered by the one-way clutch115c. In this way, the feed roller115is rotated in the direction indicated by arrow A22opposite to the media feed direction by the rotation of the separation roller116. The separation roller116rotates in the direction indicated by arrow A5opposite to the media feeding direction without receiving load from the feed roller115.

Accordingly, when the multiple media M2are multi-fed between the separation roller116and feed roller115, the media conveying apparatus100can return all of the multiple media M2to the media table103by reversing the first motor131.

As described above, the shaft116aof the separation roller116is provided with the torque limiter116c. Depending on the position of the torque limiter116c, the backlash may be present between the shaft116aand the separation roller116, where the driving force is not transmitted. Therefore, if the shaft115aof the feed roller115is rotated before the separation roller116, the shaft115aof the feed roller115may start rotating while the separation roller116is not locked. In this case, the media are not sufficiently fixed by the separation roller116and are unstable. As a result, the lowermost medium in contact with the feed roller115may be wrinkled when the shaft115aof the feed roller115starts rotating. Further, the separation roller116starts rotating while the outer circumferential surface115bof the feed roller115is not locked. The media are not sufficiently fixed by the outer circumferential surface115bof the feed roller115and are unstable. As a result, the uppermost medium in contact with the separation roller116may be wrinkled when the separation roller116starts rotating.

The media conveying apparatus100rotates the separation roller116and then rotates the shaft115aof the feed roller115. Thus, when the separation roller116starts rotating, the outer circumferential surface115bof the feed roller115is supported by the shaft115aof the feed roller115, and the media are stabled by the feed roller115. Accordingly, the media conveying apparatus100can prevent the uppermost medium in contact with the separation roller116from being wrinkled. When the shaft115aof the feed roller115starts rotating, the backlash is absent between the separation roller116and the shaft116a, and the media are stabled by the separation roller116. Accordingly, the media conveying apparatus100can prevent the lowermost medium in contact with the feed roller115from being wrinkled.

Referring back toFIG.11, the control unit151may wait for a fifth predetermined time from when the control unit151rotates the separation roller116again in step S205to when the control unit151reverses the feed roller115in step S206. The fifth predetermined time is set to a time during which the separation roller116rotates by the amount of the backlash between the separation roller116and the shaft116a. Since the control unit151can start rotating the shaft115aof the feed roller115after the backlash between the separation roller116and the shaft116ais reliably eliminated, the control unit151can reliably prevent the medium from being wrinkled.

In step S207, the control unit151waits until the media returns to the media table103. The control unit151periodically acquires the second media signal from the second media sensor117and determines that the downstream ends of media conveyed in the opposite direction to the media conveyance direction A1have passed the position of the second media sensor117when the signal value of the second media signal changes from a value indicating the presence of a medium to a value indicating the absence of a medium. The control unit151determines that the media have returned to the media table103when a sixth predetermined time has elapsed since the downstream ends of the media have passed the position of the second media sensor117. The sixth predetermined time is set to a value obtained by adding a margin to the time taken for the media conveyed in the opposite direction to the media conveyance direction A1to move from the position of the second media sensor117to the upstream end of the nip between the feed roller115and the separation roller116.

In step S208, the control unit151controls the first motor131and the second motor132to stop the feed roller115and the separation roller116.

In step S209, the control unit151restarts the media reading process. Since the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124have already been rotated, the control unit151restarts the media reading process from the operation in step S104ofFIG.8. The control unit151then returns to step S201and repeats the operations in steps S201to S209.

The feed roller115may not include the one-way clutch115c. In this case, the outer circumferential surface115bmay be rotated by the rotation of the shaft115a. In this case, in step S205, the control unit151controls the second motor132to rotate the separation roller116again in the direction opposite to the media feeding direction. In step S206, the control unit151controls the first motor131to rotate the feed roller115in the direction opposite to the media feeding direction. In other words, when returning the media to the media table103, the control unit151controls the first motor131and the second motor132such that the feed roller115rotates after the separation roller116rotates. When returning the media to the media table103, the control unit151controls the first motor131and the second motor132to set the moving speed of the outer circumferential surface115bof the feed roller115to be higher than the moving speed of the outer circumferential surface116bof the separation roller116.

In this case, when the multiple media M2are multi-fed between the separation roller116and feed roller115, the media conveying apparatus100can return all of the multiple media M2to the media table103by reversing the first motor131.

When the multi-feed of the medium has occurred, the lowermost medium in contact with the feed roller115is fed together with one or more media on top of the lowermost medium. The gravity of the one or media on top of the lowermost medium is applied to the lowermost medium in contact with the feed roller115. Therefore, if the feed roller115is rotated before the separation roller116is rotated, a downward force is applied to the lowermost medium due to the gravity of the one or more media on top of the lowermost medium while a force toward upstream direction is applied to the lowermost medium by the feed roller115. As a result, a force is applied to the lowermost medium such that the medium is twisted, and thus the lowermost medium may be wrinkled.

The media conveying apparatus100rotates the separation roller116and then rotates the feed roller115. No medium is present on top of the uppermost medium in contact with the separation roller116. Therefore, when the separation roller116is rotated before the feed roller115is rotated, only force toward upstream direction is applied to the medium in contact with the separation roller116by the separation roller116, thus reducing the possibility of wrinkles occurring on the medium in contact with the separation roller116. By rotating the separation roller116and then rotating the feed roller115, the media conveying apparatus100can prevent the medium from being wrinkled.

The control unit151sets the moving speed of the outer circumferential surface115bof the feed roller115to be higher than the moving speed of the outer circumferential surface116bof the separation roller116. Thus, the control unit151can cause the lowermost medium in contact with the feed roller115to catch up with the uppermost medium in contact with the separation roller116. Accordingly, the control unit151can return the multi-fed media to the media table103at once and complete the recovery of the media early.

The control unit151may control the first motor131and the second motor132such that the amount of rotation of the separation roller116(the amount of movement of the outer circumferential surface116b) is greater than the amount of rotation of the feed roller115(the amount of movement of the outer circumferential surface115b). By increasing the amount of rotation of the separation roller116, the control unit151can reliably return the upper medium, which has been fed together with the medium to be fed, to the media table103. By decreasing the amount of rotation of the feed roller115, the control unit151can prevent the lower medium from being wrinkled as a result of the medium being excessively returned.

Alternatively, the media conveying apparatus100may not execute the multi-feed determination process.

As described above in detail, in the media conveying apparatus100, the first motor131for driving the feed roller115, the second motor132for driving the separation roller116, and the third motor133for driving the restriction guide112are separately located. In the media conveying apparatus100, at the start of feeding of media, the first motor131, the second motor132, and the third motor133are controlled to rotate the feed roller115after the separation roller116in rotating state contacts the media. Such a configuration allows the separation roller116to favorably separate the leading ends of the media group placed on the media table103, and thus the media conveying apparatus100can favorably separate the media.

In the media conveying apparatus100, the first motor131for driving the feed roller115and the second motor132for driving the separation roller116are separately located. When returning media to the media table103when multi-feed of the medium has occurred, the media conveying apparatus100controls the first motor131and the second motor132to rotate the separation roller116and then rotate the shaft115aof the feed roller115. Such a configuration allows the media conveying apparatus100to stably return the multi-fed media to the media table103and appropriately recover the media when multi-feed of the medium has occurred.

In addition, the media conveying apparatus100can stably separate the media and stably return the multi-fed media to the media table103, regardless of the number of media conveyed together or the type of media conveyed. Further, the media conveying apparatus100can prevent the media from being jammed when returning the multi-fed media to the media table103.

FIG.13is a diagram illustrating a conveyance passage inside a media conveying apparatus200according to another embodiment of the present disclosure.

The media conveying apparatus200includes the components included in the media conveying apparatus100. However, the media conveying apparatus200includes a second motor232, a third motor233, a second transmission assembly232a, and a third transmission assembly233ainstead of the second motor132, the third motor133, the second transmission assembly132a, and the third transmission assembly133a.

The second motor232and the second transmission assembly232ahave substantially the same configurations as the second motor132and the second transmission assembly132a, respectively. However, the second motor232is coupled to the separation roller116and the cam113via the second transmission assembly232aand drives the separation roller116and the cam113. The second motor232generates a driving force for driving the separation roller116and the cam113according to control signals from the processing circuit150. The second transmission assembly232aincludes one or more pulleys, belts, and gears between the second motor232, the shaft116aserving as the rotary shaft of the separation roller116, and the rotary shaft113aof the cam113. In particular, one or more gears are located between the shaft116aof the separation roller116and the rotary shaft113aof the cam113to change the direction of rotation of the cam113from the direction of rotation of the separation roller116. The second transmission assembly232atransmits the driving force generated by the second motor232to the separation roller116and the cam113. With this configuration, the second motor232rotates the separation roller116and causes the separation roller116to separate, feed, and convey media. The second motor232also rotates the cam113to move the restriction guide112in contact with the cam113. In other words, in the media conveying apparatus200, the cam113is rotatable by the second motor232and the restriction guide112is movable by the second motor232.

The third motor233and the third transmission assembly233ahave substantially the same configurations as the third motor133and the third transmission assembly133a, respectively. Although the third motor233is coupled to the conveyance roller119and the ejection roller123via the third transmission assembly233a, the third motor233is not coupled to the cam113. The third motor233generates a driving force for driving the conveyance roller119and the ejection roller123according to control signals from the processing circuit150. The third transmission assembly233aincludes one or more pulleys, belts, and gears between the third motor233, the shaft119aserving as the rotary shaft of the conveyance roller119, and the shaft123aserving as the rotary shaft of the ejection roller123. The third transmission assembly133atransmits the driving force generated by the third motor133to the conveyance roller119and the ejection roller123. With this configuration, the third motor133rotates the conveyance roller119and the ejection roller123and causes the conveyance roller119and the ejection roller123to convey and eject media.

In the media conveying apparatus200, the control unit151and the determination unit152execute the media reading process illustrated inFIGS.8and9and the multi-feed determination process illustrated inFIG.11.

In step S103, the control unit151drives the third motor233to rotate the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124. In step S104, the control unit151drives the second motor232to rotate the separation roller116and rotate the cam113to move the restriction guide112from the set position to the released position. In step S105, the control unit151drives the first motor131to rotate the feed roller115. Thus, at the start of feeding of media, the control unit151controls the first motor131and the second motor232to rotate the feed roller115after the separation roller116in rotating state contacts the media. Further, at the start of feeding of media, the control unit151operates the second motor232and then operates the first motor131.

In step S107, the control unit151controls the second motor232to stop the separation roller116. In step S113, the control unit151controls the second motor232to rotate the separation roller116again. In these steps, the restriction guide112does not move from the released position. In step S114, the control unit151controls the first motor131to rotate the feed roller115again. Thus, at the start of feeding of the second and following media set on the restriction guide112, the control unit151controls the first motor131and the second motor232to rotate the separation roller116and then rotate the feed roller115.

In step S120, the control unit151controls the third motor233to stop the conveyance roller119, the first facing roller120, the ejection roller123, and/or the second facing roller124. In step S121, the control unit151controls the second motor232to rotate the cam113to move the restriction guide112from the released position to the set position. At this time, the separation roller116rotates in the media feeding direction. However, no problem occurs because no medium is present on the media table103.

In step S123, the control unit151controls the first motor131to rotate the feed roller115. In other words, when no medium is fed, the control unit151controls the first motor131or the second motor232to rotate the feed roller115while the restriction guide112is located at the set position. The control unit151rotates the feed roller115to move the dust adhering to the feed roller115or the separation roller116. In step S124, the control unit151controls the first motor131to stop the feed roller115.

In steps S204, S205, and S208of the multi-feed determination process, the control unit151controls the second motor232to stop or rotate the separation roller116again. In these steps, the restriction guide112does not move from the released position.

As described above in detail, the media conveying apparatus200including the common second motor232to drive the separation roller116and the restriction guide112can also favorably separate media. In addition, the media conveying apparatus200including the common second motor232to drive the separation roller116and the restriction guide112can also appropriately recover media in response to the occurrence of multi-feed of the medium.

FIG.14is a schematic diagram illustrating a configuration of a processing circuit350of a media conveying apparatus according to yet another embodiment of the present disclosure. The processing circuit350substitutes for the processing circuit150of the media conveying apparatuses100and200and executes, for example, the media reading process and the multi-feed determination process instead of the processing circuit150. The processing circuit350includes a control circuit351and a determination circuit352. These circuits may be, for example, independent integrated circuits, microprocessors, or firmware.

The control circuit351is an example of a control unit and functions as the control unit151. The control circuit351receives the operation signal from the operation device105or the interface device135, the first media signal from the first media sensor111, the second media signal from the second media sensor117, and the third media signal from the third media sensor121. The control circuit351receives a determination result of multi-feed of the medium from the determination circuit352. The control circuit351controls the first motor131, the second motor132or232, and the third motor133or233based on the received information, acquires an input image from the imaging device122, and outputs the input image to the interface device135.

The determination circuit352is an example of a determination unit and functions as the determination unit152. The determination circuit352receives the ultrasonic signal from the ultrasonic sensor118, determines whether the multi-feed of the medium occurs based on the received ultrasonic signal, and outputs the result of determination to the control circuit351.

As described above in detail, the media conveying apparatus including the processing circuit350can also favorably separate media. In addition, the media conveying apparatus including the processing circuit350can also appropriately recover media in response to the multi-feed of the medium.

According to one or more embodiments of the present disclosure, the media conveying apparatus, the media feeding method, and the control program can more appropriately recover media in response to the occurrence of multi-feed of the medium.

The functionality of the elements disclosed herein may be implemented using circuitry or processing circuitry which includes general purpose processors, special purpose processors, integrated circuits, ASICs (“Application Specific Integrated Circuits”), FPGAs (“Field-Programmable Gate Arrays”), and/or combinations thereof which are configured or programmed, using one or more programs stored in one or more memories, to perform the disclosed functionality. Processors are considered processing circuitry or circuitry as they include transistors and other circuitry therein. In the disclosure, the circuitry, units, or means are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein which is programmed or configured to carry out the recited functionality.

There is a memory that stores a computer program which includes computer instructions. These computer instructions provide the logic and routines that enable the hardware (e.g., processing circuitry or circuitry) to perform the method disclosed herein. This computer program can be implemented in known formats as a computer-readable storage medium, a computer program product, a memory device, a record medium such as a CD-ROM or DVD, and/or the memory of a FPGA or ASIC.