US20260021985A1

US20260021985A1 - Medium feeding apparatus, method for feeding medium, and computer-readable non-transitory recording medium

Info

Publication number: US20260021985A1
Application number: US19/265,708
Authority: US
Inventors: Shota Otsuka; Shumpei Koshima
Original assignee: PFU Ltd
Current assignee: PFU Ltd
Priority date: 2024-07-18
Filing date: 2025-07-10
Publication date: 2026-01-22

Abstract

A medium feeding apparatus includes a feed roller to feed a medium, a driving source to generate a driving force for driving the feed roller, a driving force transmission assembly to transmit the driving force to the feed roller, an applying part to apply a load against rotation of the feed roller, and control circuitry to control the driving source. The control circuitry controls the driving source to stop the feed roller and keeps the driving force transmission assembly static.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35 U.S.C. § 119 (a) to Japanese Patent Application No. 2024-114927, filed on Jul. 18, 2024, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.

BACKGROUND

The present disclosure relates to a medium feeding apparatus, a method for feeding a medium, and a computer-readable non-transitory recording medium.
Medium feeding apparatuses, such as scanners or printers, perform a process such as an imaging process or an image forming process on a medium while feeding the medium by a feed roller.
A document feeder includes a compression spring to bias a feed roller gear in the axial direction of a feed roller shaft to restrict the rotation of the feed roller gear. In this document feeder, the compression spring is located between the feed roller gear and the bearing of the feed roller shaft and prevents the feed roller gear from rotating in the negative direction even when the feed roller is biased to rotate in the negative direction.

SUMMARY

The medium feeding apparatus according to one aspect of the present disclosure includes a feed roller to feed a medium, a driving source to generate a driving force for driving the feed roller, a driving force transmission assembly to transmit the driving force to the feed roller, an applying part to apply a load against rotation of the feed roller, and control circuitry to control the driving source. The control circuitry controls the driving source to stop the feed roller and keeps the driving force transmission assembly static.
The method for feeding a medium according to another aspect of the present disclosure includes feeding a medium by a feed roller, generating a driving force for driving the feed roller by a driving source, transmitting the driving force to the feed roller by a driving force transmission assembly; applying a load against rotation of the feed roller by an applying part, controlling the driving source to stop the feed roller, and keeping the driving force transmission assembly static.
The computer-readable, non-transitory medium storing a computer program according to still another aspect of the present disclosure causes a medium feeding apparatus including a feed roller to feed a medium, a driving source to generate a driving force for driving the feed roller, a driving force transmission assembly to transmit the driving force to the feed roller, and an applying part to apply a load against rotation of the feed roller, to execute a process. The process includes controlling the driving source to stop the feed roller, and keeping the driving force transmission assembly static.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a medium feeding apparatus according to an embodiment;

FIG. 2 is a diagram illustrating a conveying path inside the medium feeding apparatus illustrated in FIG. 1 ;

FIG. 3 is a schematic perspective view of a driving mechanism for a feed roller;

FIG. 4 is a schematic diagram for explaining an applying part of a driving force transmission assembly illustrated in FIG. 3 ;

FIG. 5 is another schematic diagram for explaining the applying part of the driving force transmission assembly illustrated in FIG. 3 ;

FIG. 6 is a schematic diagram for explaining a circuit configuration of a first motor;

FIG. 7 is a block diagram illustrating a schematic configuration of the medium feeding apparatus illustrated in FIG. 1 ;

FIG. 8 is a block diagram illustrating a schematic configuration of a memory and a processing circuit illustrated in FIG. 7 ;

FIG. 9 is a flowchart of a medium reading process;

FIGS. 10A to 10C are schematic diagrams illustrating states of a medium;

FIG. 11A is a schematic diagram illustrating the relationship between a second gear and a third gear of the driving force transmission assembly illustrated in FIG. 3 ;

FIG. 11B is a schematic diagram illustrating the relationship between a second gear and a third gear in a comparative medium feeding apparatus;

FIG. 12 is a schematic diagram illustrating a state of a medium in the comparative medium feeding apparatus; and

FIG. 13 is a block diagram illustrating a schematic configuration of another processing circuit.

The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views.

DETAILED DESCRIPTION

In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.
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.
A medium feeding apparatus according to embodiments of the present disclosure will be described below with reference to the drawings. The technical scope of the present disclosure is not limited to the embodiments described below and covers equivalents of elements described below.
FIG. 1 is a perspective view of a medium feeding apparatus 100 that is an image scanner.
The medium feeding apparatus 100 conveys, images, and ejects a medium that is a document. Examples of the medium include paper, thick paper, a card, a booklet, and a passport. The medium feeding apparatus 100 may be a facsimile machine, a copier, or a multifunction peripheral (MFP).
In FIG. 1 , arrow A1 indicates the direction in which a medium is conveyed, arrow A2 indicates the width direction perpendicular to the medium conveying direction A1, and arrow A3 indicates the height direction perpendicular to a medium conveying path. In the following, upstream is upstream in the medium conveying direction A1, and downstream is downstream in the medium conveying direction A1. The width direction A2 is an example of a direction intersecting the medium conveying direction A1.
The medium feeding apparatus 100 includes a lower housing 101, an upper housing 102, a media tray 103, an ejection tray 104, and a display and operation device 105.
The upper housing 102 is located to cover the upper side of the medium feeding apparatus 100 and hinged to the lower housing 101 such that the upper housing 102 is opened and closed, for example, to remove a jammed medium or clean the inside of the medium feeding apparatus 100.
The media tray 103 is hinged to the lower housing 101 and is rotatable. When the medium feeding apparatus 100 is not used, the media tray 103 is located to cover the lower housing 101 and the upper housing 102 and functions as an exterior cover. When the medium feeding apparatus 100 is used, the media tray 103 is located at such a position that media to be fed and conveyed can be placed thereon. The ejection tray 104 is engaged with the lower housing 101, and the ejected media are stacked thereon. The ejection tray 104 may be engaged with the upper housing 102 with a hinge or the like.
The display and operation device 105 includes 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 a liquid crystal display and an organic electro-luminescence (EL) display. The display and operation device 105 further includes a touch-screen input device and an interface circuit that receives signals from the input device. The display and operation device 105 receives an input operation performed by a user and outputs an operation signal corresponding to the input operation performed by the user. The medium feeding apparatus 100 may include a display device and an operation device separately.
FIG. 2 is a diagram illustrating a conveying path inside the medium feeding apparatus 100.
The medium feeding apparatus 100 includes a first media sensor 111, a feed roller 112, a separation roller 113, a first conveyance roller 114, a second conveyance roller 115, a second media sensor 116, an imaging device 117 including an image sensor, a first ejection roller 118, and a second ejection roller 119 along the conveying path.
The number of each of the feed roller 112, the separation roller 113, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and/or the second ejection roller 119 is not limited to one but may be two or more. When the feed roller 112, the separation roller 113, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and/or the second ejection roller 119 are formed of multiple rollers, the multiple rollers are located at intervals in the width direction A2.
The upper face of the lower housing 101 forms a lower guide 101 a for the medium conveying path, and the lower face of the upper housing 102 forms an upper guide 102 a for the medium conveying path. As illustrated in FIG. 2 , the medium conveying path is a so-called straight path, and the vertical relative positions of the front side and the back side of a medium do not change between when the medium is fed from the media tray 103 and when the medium is ejected onto the ejection tray 104.
The first media sensor 111 is located upstream from the feed roller 112 and the separation roller 113. The first media sensor 111 includes a contact sensor and detects whether a medium is placed on the media tray 103. The first media sensor 111 generates and outputs a first media signal whose signal value changes depending on whether a medium is placed on the media tray 103. The first media sensor 111 is not limited to a contact sensor. The first media sensor 111 may be any other sensor, such as an optical detection sensor, which detects the presence of a medium.
The feed roller 112 is in the lower housing 101, separates the media on the media tray 103 one by one from the bottom, and sequentially feeds the media. The separation roller 113 is a so-called brake roller or retard roller, located in the upper housing 102, and faces the feed roller 112. The separation roller 113 separates a medium from the media on the media tray 103. The separation roller 113 is rotatable in the direction indicated by arrow A5 opposite to the rotation direction for conveying a medium (may be referred to as a medium feeding direction in the following description). Alternatively, the separation roller 113 is stopped. Instead of the separation roller 113, a separation pad may be used.
The first conveyance roller 114 and the second conveyance roller 115 are located downstream from the feed roller 112 and the separation roller 113 in the medium conveying direction A1 and face each other. The first conveyance roller 114 and the second conveyance roller 115 convey the medium fed by the feed roller 112 and the separation roller 113 to the imaging device 117.
The second media sensor 116 is located downstream from the first conveyance roller 114 and the second conveyance roller 115 and upstream from the imaging device 117, and detects the leading end and the trailing end of the medium conveyed to the detection position of the second media sensor 116. The second media sensor 116 includes a light emitter, a light receiver, and a light guide. The light emitter and the light receiver are located on one side of the medium conveying path, and the light guide faces the light emitter and the light receiver across the medium conveying path. The light guide is, for example, a U-shaped prism. The light emitter is, for example, a light-emitting diode (LED) and emits light toward the medium conveying path. The light receiver is, for example, a photodiode and receives light emitted from the light emitter and guided by the light guide. When a medium is present at the position facing the second media sensor 116, the light emitted from the light emitter is blocked by the medium, and the light receiver does not detect the light emitted from the light emitter. The light receiver generates and outputs a second media signal based on the intensity of the light received. The second media signal changes in signal value depending on whether a medium is present at the position of the second media sensor 116.
The light guide may be substituted by a reflector such as a mirror. The light emitter and the light receiver may be located to face each other across the medium conveying path. Further, the second media sensor 116 may detect the medium using, for example, a contact sensor that allows a predetermined amount of electrical current to flow when a medium is in contact or not in contact therewith.
The imaging device 117 images the medium conveyed by the first conveyance roller 114. The imaging device 117 includes a first imaging device 117 a and a second imaging device 117 b facing each other across the medium conveying path.
The first imaging device 117 a includes an imaging sensor that is a unity-magnification contact image sensor (CIS). The CIS includes complementary metal oxide semiconductor (CMOS) imaging elements aligned linearly in the main scanning direction. The first imaging device 117 a further includes a lens that forms an image on the imaging elements and an analog-to-digital (A/D) converter. The A/D converter amplifies the electrical signals output from the imaging elements and performs analog-to-digital (A/D) conversion. The first imaging device 117 a images the front side of the medium being conveyed, generates input images sequentially, and outputs the input images.
Similarly, the second imaging device 117 b includes an imaging sensor that is a unity-magnification CIS including CMOS imaging elements aligned linearly in the main scanning direction. The second imaging device 117 b further includes a lens that forms an image on the imaging elements and an A/D converter. The A/D converter amplifies the electrical signals output from the imaging elements and performs A/D conversion. The second imaging device 117 b images the back side of the medium being conveyed, generates an input image, and outputs the input image.
Alternatively, the medium feeding apparatus 100 may include only one of the first imaging device 117 a and the second imaging device 117 b to read only one side of the medium. The imaging sensor may be a line sensor that employs a unity-magnification CIS including charge-coupled device (CCD) imaging elements. Alternatively, the imaging sensor may be a reduction-optical line sensor including CMOS or CCD imaging elements.
The first ejection roller 118 and the second ejection roller 119 are located downstream from the imaging device 117 in the medium conveying direction A1 and face each other. The first ejection roller 118 and the second ejection roller 119 eject the medium that is conveyed by the first conveyance roller 114 and the second conveyance roller 115 and is processed (imaged) by the imaging device 117 to the ejection tray 104.
The media placed on the media tray 103 are conveyed between the lower guide 101 a and the upper guide 102 a in the medium conveying direction A1 as the feed roller 112 rotates in the direction indicated by arrow A4 in FIG. 2 , which is the medium feeding direction. The separation roller 113 rotates in the direction indicated by arrow A5 opposite to the medium feeding direction or is stopped when a medium is conveyed. When two or more media are placed on the media tray 103, only the medium in contact with the feed roller 112 is separated from the rest of the media on the media tray 103 due to the action of the feed roller 112 and the separation roller 113. This operation prevents the feeding of a medium other than the separated medium (prevention of multi-feed).
The medium is fed between the first conveyance roller 114 and the second conveyance roller 115 while being guided by the lower guide 101 a and the upper guide 102 a. The medium is fed between the first imaging device 117 a and the second imaging device 117 b as the first conveyance roller 114 and the second conveyance roller 115 rotate in the directions indicated by arrows A6 and A7 in FIG. 2 , respectively. The medium read by the imaging device 117 is ejected onto the ejection tray 104 as the first ejection roller 118 and the second ejection roller 119 rotate in the directions indicated by arrows A8 and A9 in FIG. 2 , respectively.
FIG. 3 is a schematic perspective view of a driving mechanism for the feed roller 112 as viewed from the upstream side and the left side.
As illustrated in FIG. 3 , the medium feeding apparatus 100 includes a first motor 130 and a driving force transmission assembly 131.
The first motor 130 is an example of a driving source and generates a driving force for rotating the feed roller 112 according to a control signal from a processing circuit described later. The first motor 130 is, for example, a direct current (DC) motor. The medium feeding apparatus 100 can reduce the component cost and the power consumption by using a DC motor as the first motor 130. The first motor 130 is not limited to a DC motor but may be another motor, such as a stepper motor. The first motor 130 generates a driving force for rotating the feed roller 112 in the medium feeding direction A4.
The driving force transmission assembly 131 includes first and second pulleys 132 a and 132 b, a belt 133, first, second, and third gears 134 a, 134 b, and 134 c, a shaft 135, and an applying part 136.
The first pulley 132 a is mounted on the rotation shaft of the first motor 130. The belt 133 is stretched around the first pulley 132 a and the second pulley 132 b. The second pulley 132 b includes a gear portion engaged with the first gear 134 a. The first gear 134 a is engaged with the second gear 134 b. The second gear 134 b is engaged with the third gear 134 c. The third gear 134 c is mounted on the shaft 135. Further, the feed roller 112 and the applying part 136 are located on the shaft 135. The shaft 135 functions as the rotation shaft of the feed roller 112.
The feed roller 112 includes a one-way clutch 112 a. The one-way clutch 112 a is located between the feed roller 112 and the shaft 135. When the feed roller 112 is rotated in the medium feeding direction A4 by the driving force from the first motor 130, the one-way clutch 112 a transmits the rotational force of the shaft 135 to the feed roller 112. By contrast, when the feed roller 112 is rotated in the medium feeding direction A4 by the medium being fed, the one-way clutch 112 a does not transmit the rotational force of the feed roller 112 to the shaft 135, allowing the feed roller 112 to idle relative to the shaft 135.
The applying part 136 applies a load against the rotation of the feed roller 112 to the driving force transmission assembly 131, particularly, the third gear 134 c and the shaft 135. The operation of the feed roller 112 will be described below.
When the first motor 130 generates a driving force to rotate in the direction indicated by arrow B1, the first and second pulleys 132 a and 132 b rotate in the directions indicated by arrows B1 and B2, respectively. Then, the first to third gears 134 a to 134 c rotate in the directions indicated by arrows B3 to B5, respectively. As a result, the feed roller 112 is rotated by the driving force from the first motor 130 in the medium feeding direction A4, together with the shaft 135 being the rotation shaft thereof. As described above, the driving force transmission assembly 131 including the first and second pulleys 132 a and 132 b, the belt 133, the first to third gears 134 a to 134 c, and the shaft 135 transmits the driving force for rotating the feed roller 112 from the first motor 130 to the feed roller 112.
FIGS. 4 and 5 are schematic diagrams for explaining the applying part 136. FIG. 4 is a perspective view of the shaft 135, the feed roller 112, and the applying part 136 as viewed from the downstream side. FIG. 5 is a cross-sectional view of the shaft 135, the feed roller 112, and the applying part 136.
As illustrated in FIGS. 4 and 5 , the applying part 136 includes a support 137, a contact part 138, and a pressing part 139.
The support 137 is a bearing of the shaft 135. The support 137 includes an engaging portion 137 a. When the engaging portion 137 a is engaged with a frame in the lower housing 101, the support 137 is fixed to the lower housing 101. Thus, the support 137 supports the shaft 135 to fix the position of the shaft 135 relative to the lower housing 101. The contact part 138 is a bearing of the shaft 135 and located between the support 137 and the third gear 134 c. The contact part 138 is made of, for example, rubber, resin, or metal and is located to contact the third gear 134 c. In particular, the contact part 138 is located to contact the side face of the third gear 134 c, that is, a face of the third gear 134 c intersecting the rotation axis. The contact part 138 applies a frictional force for restricting the rotation of the third gear 134 c to the third gear 134 c.
The frictional force applied to the third gear 134 c by the contact part 138 is set to be smaller than the driving force applied to the third gear 134 c by the first motor 130. Accordingly, when the second gear 134 b is rotated by the driving force from the first motor 130, the third gear 134 c is rotated by the rotation of the second gear 134 b. By contrast, the frictional force applied to the third gear 134 c by the contact part 138 is set to be greater than the frictional force generated in the one-way clutch 112 a of the feed roller 112. Accordingly, when the shaft 135 is about to be rotated by the frictional force generated in the one-way clutch 112 a, the third gear 134 c is prevented from rotating by the frictional force by the contact part 138.
The pressing part 139 is a spring such as a compression coil spring. The pressing part 139 may be another elastic member, such as another spring (e.g., a flat spring) or a rubber member. The pressing part 139 is located between the support 137 and the contact part 138 along the shaft 135. One end of the pressing part 139 is attached to the support 137 fixed to the lower housing 101, and the other end of the pressing part 139 is attached to the face of the contact part 138 on the side opposite to the third gear 134 c. The pressing part 139 presses the contact part 138 toward the third gear 134 c. Accordingly, the contact part 138 presses the third gear 134 c in the axial direction thereof and applies to the third gear 134 c the frictional force for restricting the rotation of the third gear 134 c.
As a result, the applying part 136 applies a load against the rotation of the feed roller 112 to the driving force transmission assembly 131 including the third gear 134 c and the shaft 135. The applying part 136 presses the third gear 134 c in the axial direction, thereby efficiently applying the frictional force to the third gear 134 c and appropriately restricting the rotation of the feed roller 112.
The support 137 may be omitted, and the pressing part 139 may be in direct contact with the frame in the lower housing 101. Further, the contact part 138 may be omitted, and the pressing part 139 may be in direct contact with the third gear 134 c. Instead of the pressing part 139, for example, a fixing part may be used to retain the contact part 138 at the position in contact with the third gear 134 c.
FIG. 6 is a schematic diagram for explaining a circuit configuration of the first motor 130.
As illustrated in FIG. 6 , the circuit inside the first motor 130 includes a first motor element 130 a and a first resistor 130 b. The first motor element 130 a is driven according to the voltage applied to the terminals at both ends of the first motor element 130 a or the incoming current. The first resistor 130 b is a variable resistor. The first resistor 130 b may be a fixed resistor. The circuit may be configured to short the first resistor 130 b. FIG. 7 is a block diagram illustrating a schematic configuration of the medium feeding apparatus 100.
The medium feeding apparatus 100 further includes a second motor 141, an interface device 142, a memory 150, and a processing circuit 160, in addition to the components described above.
The second motor 141 is an example of a second driving source. The second motor 141 generates a driving force for rotating the feed roller 112, the separation roller 113, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and the second ejection roller 119 according to a control signal from the processing circuit 160. The second motor 141 is, for example, a DC motor. The medium feeding apparatus 100 can reduce the component cost and the power consumption by using a DC motor as the second motor 141. The second motor 141 is not limited to a DC motor but may be another motor, such as a stepper motor.
The separation roller 113, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and/or the second ejection roller 119 may be driven by the driving force from the first motor 130. The feed roller 112 may be driven by the driving force from the second motor 141. The second conveyance roller 115 and the second ejection roller 119 may be driven rollers to be rotated by the first conveyance roller 114 and the first ejection roller 118, respectively. Further, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and/or the second ejection roller 119 may be rotated by a driving force generated by a motor different from the first motor 130 and the second motor 141.
The interface device 142 includes an interface circuit compatible with a serial bus such as a universal serial bus (USB) and is electrically connected to an information processing apparatus (e.g., a personal computer or a mobile information processing terminal) to transmit and receive input images and various kinds of information to and from the information processing apparatus. The interface device 142 may be substituted by a communication device that includes an antenna to transmit and receive wireless signals and a wireless communication interface device to transmit and receive 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 device may include a wired communication interface device to transmit and receive signals through a wired communication line according to a communication protocol, such as a wired LAN communication protocol.
The memory 150 includes 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 memory 150 stores, for example, computer programs, databases, and tables used for various processes performed by the medium feeding apparatus 100. The computer programs may be installed in the memory 150 from a computer-readable portable recording medium using, for example, a setup program. Examples of the portable recording medium include a compact disc read-only memory (CD-ROM) and a digital versatile disc read-only memory (DVD-ROM). The computer programs may be distributed from, for example, a server and installed in the memory 150.
The processing circuit 160 operates according to a program prestored in the memory 150. The processing circuit is, 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 circuit 160.
The processing circuit 160 is connected to the display and operation device 105, the first media sensor 111, the second media sensor 116, the imaging device 117, the first motor 130, the second motor 141, the interface device 142, the memory 150, etc., and controls these devices. The processing circuit 160 controls the driving of the first motor 130 and the second motor 141, the imaging by the imaging device 117, etc., according to the first and second media signals received from the first and second media sensors 111 and 116, respectively. The processing circuit 160 obtains an input image from the imaging device 117 and transmits the input image to the information processing apparatus via the interface device 142.
FIG. 8 is a block diagram illustrating a schematic configuration of the memory 150 and the processing circuit 160.
As illustrated in FIG. 8 , the memory 150 stores a control program 151 and an image obtaining program 152. These programs are functional modules implemented by software that operates on the processor. The processing circuit 160 reads the programs from the memory 150 and operates according to the read programs. Thus, the processing circuit 160 functions as a control unit 161 and an image obtaining unit 162.
FIG. 9 is a flowchart of a medium reading process performed by the medium feeding apparatus 100.
The medium reading process performed by the medium feeding apparatus 100 is described below with reference to the flowchart of FIG. 9 . The process described below is executed, for example, by the processing circuit 160 in cooperation with the components of the medium feeding apparatus 100 according to the programs prestored in the memory 150.
In step S101, the control unit 161 stands by until an operation signal instructing the reading of a medium is received from the display and operation device 105 or an information processing apparatus via the interface device 142. The operation signal is output when a user inputs an instruction to read the medium using the display and operation device 105 or the information processing apparatus.
In step S102, the control unit 161 obtains the first media signal from the first media sensor 111 and determines whether a medium is placed on the media tray 103 based on the obtained media signal. The control unit 161 ends the series of steps when no medium is placed on the media tray 103.
By contrast, when a medium is placed on the media tray 103 (No in step S102), the control unit 161 controls the first motor 130 to rotate the feed roller 112 in step S103. Further, the control unit 161 controls the second motor 141 to rotate the separation roller 113, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and/or the second ejection roller 119. Thus, the control unit 161 feeds and conveys the medium.
FIG. 10A is a schematic diagram illustrating the state of a medium immediately after the start of feeding.
As illustrated in FIG. 10A, when the feed roller 112 rotates in the medium feeding direction A4, a medium M1 that is the lowest among the media placed on the media tray 103 is fed. Further, the separation roller 113 rotates in the direction A5 opposite to the medium feeding direction, and the media on the media tray 103 other than the medium M1 are not fed but remain on the media tray 103.
In step S104, the control unit 161 waits until the leading end of the fed medium passes through the nip between the first conveyance roller 114 and the second conveyance roller 115. For example, the control unit 161 periodically obtains the second media signal from the second media sensor 116. The control unit 161 determines that the leading end of the medium passes the first conveyance roller 114 and the second conveyance roller 115 when the signal value of the second media signal changes from the value indicating the absence of a medium to the value indicating the presence of a medium.
In step S105, the control unit 161 controls the first motor 130 to stop the feed roller 112. The control unit 161 sets the voltage applied to the terminals at both ends of the first motor element 130 a or the current flowing into the first motor element 130 a so that the rotation speed of the feed roller 112 becomes zero. In other words, the control unit 161 controls the first motor 130 to stop the feed roller 112 by applying a predetermined voltage to the first motor 130 to allow a predetermined current to flow. The predetermined current is the amount of current corresponding to the hold current in a stepper motor. Thus, after stopping the feed roller 112, the control unit 161 can keep the driving force transmission assembly 131 for the feed roller 112 static.
In particular, the control unit 161 controls the first motor 130 to prevent the feed roller 112 from being rotated by the separation roller 113 when the feed roller 112 contacts the separation roller 113 rotating in the direction A5 opposite to the medium feeding direction. With this control, when the trailing end of the medium being fed passes through the nip between the feed roller 112 and the separation roller 113, the feed roller 112 and the separation roller 113 contact each other and stop.
The control unit 161 may control the first motor 130 to stop the feed roller 112 by shorting the terminals at both ends of the first motor element 130 a. Also in this case, the control unit 161 can keep the driving force transmission assembly 131 for the feed roller 112 static after stopping the feed roller 112.
As described above, the control unit 161 controls the first motor 130 to stop the feed roller 112. In particular, the control unit 161 controls the first motor 130 to stop the feed roller 112 after the leading end of the medium passes the first conveyance roller 114 and the second conveyance roller 115.
FIG. 10B is a schematic diagram illustrating the state of a medium immediately after the leading end thereof passes the first conveyance roller 114 and the second conveyance roller 115.
As illustrated in FIG. 10B, after the leading end of the medium M1 passes the first conveyance roller 114 and the second conveyance roller 115, the feed roller 112 is stopped, and then the medium M1 is conveyed by the first conveyance roller 114 and the second conveyance roller 115. The feed roller 112 is rotated in the medium conveying direction A4 by the medium M1 conveyed by the first conveyance roller 114 and the second conveyance roller 115. This can prevent the following inconvenience. If the feed roller 112 stops, the medium M1 pushed by the feed roller 112 is bent and jammed between the feed roller 112 and the first conveyance roller 114 facing the second conveyance roller 115.
In step S106, the image obtaining unit 162 controls the imaging device 117 to start imaging the medium.
In step S107, the control unit 161 waits until the trailing end of the medium passes through the nip between the feed roller 112 and the separation roller 113. The control unit 161 determines that the trailing end of the medium passes the nip between the feed roller 112 and the separation roller 113, for example, when a first predetermined time elapses after the feeding of the medium is started. The first predetermined time is set to the sum of the time from when the leading end of the largest medium supported by the medium feeding apparatus 100 passes the upstream end of the nip between the feed roller 112 and the separation roller 113 to when the trailing end of the medium reaches the downstream end of the nip and a margin. The medium feeding apparatus 100 may further include another media sensor, which is similar to the second media sensor 116, between the feed roller 112 and the first conveyance roller 114 in the medium conveying direction A1, particularly near the feed roller 112. In that case, the control unit 161 may determine that the trailing end of the medium passes the nip between the feed roller 112 and the separation roller 113 when the signal value of the second media signal output from the second media sensor changes from the value indicating the presence of a medium to the value indicating the absence of a medium.
In this manner, the control unit 161 controls the first motor 130 to stop the feed roller 112 at least while the trailing end of the medium passes through the nip between the feed roller 112 and the separation roller 113.
FIG. 10C is a schematic diagram illustrating the state of a medium immediately after the trailing end of the medium passes through the nip between the feed roller 112 and the separation roller 113.
The feeding of the medium subsequent to the medium M1 can be started after the trailing end of the medium M1 passes the nip between the feed roller 112 and the separation roller 113 as illustrated in FIG. 10C. Stopping the feed roller 112 while the trailing end of the medium is passing through the nip between the feed roller 112 and the separation roller 113 can prevent the media placed on the media tray 103 other than the medium M1 from being fed. Thus, the occurrence of the multi-feed of media is prevented.
In step S108, the control unit 161 determines whether a medium remains on the media tray 103 based on the first media signal received from the first media sensor 111.
When a medium remains on the media tray 103 (Yes in step S108), the control unit 161 controls the first motor 130 to again rotate the feed roller 112 to feed and convey the subsequent medium in step S109.
In step S110, the image obtaining unit 162 waits until the trailing end of the preceding medium passes the imaging position. The control unit 161 obtains the second media signal periodically from the second media sensor 116 and determines that the trailing end of the preceding medium passes the position of the second media sensor 116 when the signal value of the second media signal changes from the value indicating the presence of a medium to the value indicating the absence of a medium. The control unit 161 determines that the trailing end of the preceding medium passes the imaging position when a second predetermined time elapses from when the trailing end of the preceding medium passes the position of the second media sensor 116. The second predetermined time is set to the sum of the time for a medium to move from the position of the second media sensor 116 to the imaging position and a margin.
In step S111, the image obtaining unit 162 stops the imaging by the imaging device 117 and obtains an input image from the imaging device 117. The image obtaining unit 162 transmits (i.e., outputs) the input image to the information processing apparatus via the interface device 142. The control unit 161 then returns the process to step S104 and repeats the process from step S104 for the subsequent medium.
By contrast, when no medium remains on the media tray 103 (No in step S108), the image obtaining unit 162 waits until the trailing end of the conveyed medium passes the imaging position in step S112, similarly to the operation in step S110.
In step S113, the image obtaining unit 162 obtains and transmits (i.e., outputs) the input image to the information processing apparatus via the interface device 142, similarly to the operation in step S111.
In step S114, the control unit 161 waits until the trailing end of the medium passes the position of the first ejection roller 118 and the second ejection roller 119. The control unit 161 determines that the trailing end of the medium passes the first ejection roller 118 and the second ejection roller 119 when a third predetermined time elapses from when the trailing end of the medium passes the position of the second media sensor 116. The third predetermined time is set to the sum of the time for the medium to move from the position of the second media sensor 116 to the downstream end of the nip between the first ejection roller 118 and the second ejection roller 119 and a margin.
In step S115, the control unit 161 controls the second motor 141 to stop the separation roller 113, the first conveyance roller 114, the second conveyance roller 115, the first ejection roller 118, and/or the second ejection roller 119, and ends the series of steps.
The technical significance of stopping the feed roller 112 while applying the load against the rotation of the feed roller 112 to the driving force transmission assembly 131 by the applying part 136 will be described.
FIG. 11A is a schematic diagram illustrating the relationship between the second gear 134 b and the third gear 134 c.
In step S103 or step S109, when the control unit 161 controls the first motor 130 to rotate the feed roller 112, the second gear 134 b rotates in the direction B4 by the driving force from the first motor 130 as illustrated in FIG. 11A. As a result, a front side C1 of a tooth of the second gear 134 b in the rotation direction B4 contacts a rear side C2 of a tooth of the third gear 134 c in the rotation direction B5. Then, the third gear 134 c and the shaft 135 are rotated in the direction B5 by the second gear 134 b. As a result, the feed roller 112 rotates in the medium feeding direction A4 as illustrated in FIG. 10A.
After that, when the control unit 161 controls the first motor 130 to stop the feed roller 112 in step S105, the second gear 134 b stops. At this time, as illustrated in FIG. 10B, the feed roller 112 is rotated in the medium conveying direction A4 by the medium M1 conveyed by the first conveyance roller 114 and the second conveyance roller 115.
However, the one-way clutch 112 a prevents the rotational force of the feed roller 112 from being transmitted to the shaft 135. At this time, although a frictional force is generated in the one-way clutch 112 a, the frictional force applied to the third gear 134 c by the applying part 136 is set to be greater than the frictional force generated by the one-way clutch 112 a as described above. Accordingly, the shaft 135 and the third gear 134 c remain stopped, and the front side C1 of the tooth of the second gear 134 b in the rotation direction B4 remains in contact with the rear side C2 of the tooth of the third gear 134 c in the rotation direction B5.
When the trailing end of the medium passes through the nip between the feed roller 112 and the separation roller 113 in step S107, the feed roller 112 contacts the separation roller 113 as illustrated in FIG. 10C. Then, the feed roller 112 is about to rotate in the direction opposite to the medium feeding direction A4, following the separation roller 113 rotating in the direction A5 opposite to the medium feeding direction. However, the second gear 134 b is stopped by the driving force from the first motor 130. Further, since the front side C1 of the tooth of the second gear 134 b in the rotation direction B4 is in contact with the rear side C2 of the tooth of the third gear 134 c in the rotation direction B5, the shaft 135 and the third gear 134 c are prevented from rotating in the direction opposite to the direction B5. As a result, the feed roller 112 does not rotate in the direction opposite to the medium feeding direction A4.
As described above, when the control unit 161 drives the first motor 130 to stop the feed roller 112, the feed roller 112 is prevented from rotating in the direction opposite to the medium feeding direction A4 by the load applied by the applying part 136. In other words, when the control unit 161 drives the first motor 130 to stop the feed roller 112, the applying part 136 applies a load against the rotation of the feed roller 112 to the driving force transmission assembly 131 to prevent the feed roller 112 from rotating in the direction opposite to the medium feeding direction A4.
FIG. 11B is a schematic diagram illustrating the relationship between the second gear and the third gear in a comparative medium feeding apparatus.
In FIG. 11B, a gear G2 (the third gear) is mounted on the shaft of a feed roller R1 (see FIG. 12 ), and a gear G1 (the second gear) transmits the driving force from a motor to the gear G2. In this medium feeding apparatus, a load against the rotation of the feed roller R1 is not applied to the gear G2. Accordingly, when the feed roller R1 is stopped, the gear G2 rotates in the direction B5 by the frictional force generated in the one-way clutch 112 a. Accordingly, a front side D1 of a tooth of the gear G1 in the rotation direction B4 separates from a rear side d2 of a tooth of the gear G2 in the rotation direction B5, and a backlash (gap) is present between the gear G1 and the gear G2. When the feed roller R1 contacts the separation roller R2 after the trailing end of the medium passes through the nip therebetween, the separation roller R2 rotates in the direction A5 opposite to the medium feeding direction due to the elastic deformation of the roller surface (rubber). The feed roller R1 is forced to rotate in the direction opposite to the medium feeding direction A4 by the force from the separation roller R2 rotating in the direction A5 opposite to the medium feeding direction.
FIG. 12 is a schematic diagram illustrating a state immediately before a subsequent medium is fed in the comparative medium feeding apparatus.
When the feed roller R1 rotates in the direction indicated by arrow E1 opposite to the medium feeding direction following the separation roller R2 rotating in the direction indicated by arrow E2 opposite to the medium feeding direction, the leading end of a medium M2 in contact with the feed roller R1 among the media placed on the media tray is pushed back toward the media tray. However, the medium M2 is prevented from returning toward the media tray since other media are stacked on the medium M2. Accordingly, as illustrated in FIG. 12 , the leading end of the medium M2 in contact with the feed roller R1 is bent, and the medium is jammed or damaged.
In the medium feeding apparatus 100, the applying part 136 applies a load against the rotation of the feed roller 112 to the driving force transmission assembly 131 so that a backlash does not occur between the second gear 134 b and the third gear 134 c when the feed roller 112 follows the medium conveyed by the first conveyance roller 114 and the second conveyance roller 115 or when the feed roller 112 is about to follow the separation roller 113. The medium feeding apparatus 100 can prevent the leading end of the subsequent medium from bending, which results in the jamming of the medium or damage to the medium, by stopping the feed roller 112 while applying the load against the rotation of the feed roller 112 to the driving force transmission assembly 131 by the applying part 136.
As described above in detail, in the medium feeding apparatus 100, the control unit 161 controls the first motor 130 to stop the feed roller 112, and the applying part 136 applies a load against the rotation of the feed roller 112 to the driving force transmission assembly 131. Accordingly, the medium feeding apparatus 100 can perform the pseudo hold when stopping the feed roller 112 and can prevent the jamming of the medium or damage to the medium. Thus, the medium feeding apparatus 100 can properly feed a medium.
In addition, the medium feeding apparatus 100 applies a load against the rotation of the feed roller 112 to the driving force transmission assembly 131 by using the support 137, the contact part 138, and the pressing part 139, which are for general-purpose use, as the bearing of the shaft 135 being the rotation shaft of the feed roller 112. As a result, the medium feeding apparatus 100 can prevent the jamming of the medium or damage to the medium while minimizing increases in the apparatus cost.
FIG. 13 is a diagram illustrating a schematic configuration of a processing circuit 260 included in another medium feeding apparatus.
The processing circuit 260 is used in place of the processing circuit 160 and performs the medium reading process, etc., in place of the processing circuit 160. The processing circuit 260 includes a control circuit 261 and an image obtaining circuit 262. These circuits may be implemented by independent integrated circuits, microprocessors, firmware, or a combination thereof.
The control circuit 261 is an example of control circuitry and functions like the control unit 161. The control circuit 261 receives the operation signal from the display and operation device 105 or the interface device 142, the first media signal from the first media sensor 111, and the second media signal from the second media sensor 116. The control circuit 261 controls the first motor 130 and the second motor 141 based on the received signals.
The image obtaining circuit 262 functions like the image obtaining unit 162. The image obtaining circuit 262 receives the second media signal from the second media sensor 116, obtains an input image from the imaging device 117 based on the received second media signal, and outputs the input image to the interface device 142.
The medium feeding apparatus can properly feed a medium as described above, also when the processing circuit 260 is used.
Embodiments of the present disclosure are not limited to the above-described embodiments. For example, the applying part 136 may apply the load against the rotation of the feed roller 112 to the feed roller 112, not the driving force transmission assembly 131. In this case, the medium feeding apparatus further includes a contact part similar to the contact part 138 and/or a pressing part similar to the pressing part 139 between the feed roller 112 and a frame in the lower housing 101. The contact part contacts a side face of the feed roller 112 to apply a frictional force to the feed roller 112. The pressing part presses the contact part toward the feed roller 112.
Further, the medium conveying path may be a so-called U-turn path, and the medium feeding apparatus may feed and convey media placed on the media tray sequentially from the top and eject the media to the ejection tray. In this configuration, the separation roller is located below the feed roller to face the feed roller.
The medium feeding apparatus may include an image forming device instead of or in addition to the imaging device 117. The image forming device employs, for example, an inkjet printing method or a laser printing method, is located at the position corresponding to the position of the imaging device 117, and forms an image (prints predetermined information) on a medium conveyed.
The medium feeding apparatus according to one aspect of the present disclosure includes a feed roller to feed a medium, a driving source to generate a driving force for driving the feed roller, an applying part to apply a load against rotation of the feed roller, and control circuitry configured to control the driving source. When the driving source controls the driving source to stop the feed roller, the feed roller is prevented from rotating in the direction opposite to a medium feeding direction by the load applied by the applying part.
The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
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, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), 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 an FPGA or ASIC.

Claims

1. A medium feeding apparatus comprising:

a feed roller to feed a medium;

a driving source to generate a driving force for driving the feed roller;

a driving force transmission assembly to transmit the driving force to the feed roller;

an applying part to apply a load against rotation of the feed roller; and

control circuitry configured to control the driving source,

wherein the control circuitry controls the driving source to stop the feed roller and keeps the driving force transmission assembly static.

2. The medium feeding apparatus according to claim 1, further comprising a conveyance roller located downstream from the feed roller in a medium conveying direction,

wherein the control circuitry controls the driving source to stop the feed roller after a leading end of the medium passes the conveyance roller.

3. The medium feeding apparatus according to claim 1, further comprising a separation roller facing the feed roller and rotatable in a direction opposite to a medium feeding direction,

wherein the control circuitry controls the driving source to stop the feed roller at least while a trailing end of the medium passes through a nip between the feed roller and the separation roller.

4. The medium feeding apparatus according to claim 1, further comprising a gear to transmit the driving force to the feed roller,

wherein the applying part presses the gear in an axial direction of the gear to apply the load against rotation of the feed roller.

5. The medium feeding apparatus according to claim 1, wherein the driving source is a direct-current motor.

6. The medium feeding apparatus according to claim 5,

wherein the control circuitry shorts terminals at both ends of the direct-current motor or allows a predetermined current to flow through the direct-current motor to stop the feed roller.

7. A method for feeding a medium, the method comprising:

feeding a medium by a feed roller;

generating a driving force for driving the feed roller by a driving source;

transmitting the driving force to the feed roller by a driving force transmission assembly;

applying a load against rotation of the feed roller by an applying part;

controlling the driving source to stop the feed roller; and

keeping the driving force transmission assembly static.

8. A computer-readable, non-transitory medium storing a computer program, wherein the computer program causes a medium feeding apparatus including a feed roller to feed a medium, a driving source to generate a driving force for driving the feed roller, a driving force transmission assembly to transmit the driving force to the feed roller, and an applying part to apply a load against rotation of the feed roller, to execute a process,

the process comprising:

controlling the driving source to stop the feed roller; and

keeping the driving force transmission assembly static.