Media transport device

Abstract

To provide a medium carrier capable of separating and feeding mediums more suitably.SOLUTION: A medium carrier includes a unit that includes a first gear to rotate according to a drive force generated by a motor, a second gear provided on a rotation axis of a separation roller, and a third gear provided between the first gear and the second gear, and is supported swingably about an axis of the first gear as rotary axis. By a force generated through restricting the torque for the separation roller to rotate in a direction reverse to a rotating direction of the feed roller by a torque limiter, the separation roller is pressed toward the feed roller. The first gear rotates in a direction to generate a force making the separation roller spaced from the feed roller due to a rotation of the motor. The third gear is a two-step gear, in which a gear on the second gear side has a number of teeth greater than a number of teeth of a gear on the first gear side.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a medium transport device, and more particularly to a medium transport device that separates and feeds media, a control method, and a control program. [Background technology]

[0002] In recent years, there has been a demand for medium conveying devices that separate and feed media to be able to convey not only paper but also media having a thickness such as a passport.

[0003] A feeding device has been disclosed in which the reverse roller rotates in the conveying direction and the return direction relative to the sheet medium by changing the frictional force according to the number of sheets of sheet medium entering the nip portion between the feed roller and the reverse roller (see Patent Document 1). This feeding device has a configuration in which the nip pressure in the nip portion between the feed roller and the reverse roller changes, and the feeding drive time when the nip pressure is at its lowest is set to be longer than the time for the sheet medium to pass through the nip portion at a fixed point.

[0004] A sheet conveying device has been disclosed in which a retard roller is rotatably supported on a rotary support shaft, and one end of the rotary support shaft is provided with a locking claw and a lever for swinging the locking claw (see Patent Document 2). In this sheet conveying device, a retard roller holder supported on the device body is provided with a locked portion to which the locking claw is locked, and the retard roller can be attached to and detached from the device body by operating the lever. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-249250 A [Patent Document 2] JP 2012-166926 A Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable for media handling devices to better separate and feed media.

[0007] An object of the present invention is to provide a medium transport device that can more appropriately separate and feed media. [Means for solving the problem]

[0008] A media conveying device according to one aspect of the present invention has a feed roller that feeds a medium, a separation roller arranged opposite the feed roller and separating the medium, a torque limiter provided on the rotational axis of the separation roller, a motor that generates a driving force to rotate the separation roller in a direction opposite to the media feeding direction, and a unit that includes a first gear that rotates in response to the driving force generated by the motor, a second gear provided on the rotational axis of the separation roller, and a third gear provided between the first gear and the second gear, and is supported so as to be swingable around the axis of the first gear as a rotational axis, wherein the separation roller is pressed towards the feed roller by a force generated by the torque limiter limiting the torque that causes the separation roller to rotate in the direction opposite to the rotational direction of the feed roller, and the first gear rotates in a direction that generates a force that separates the separation roller from the feed roller due to the rotation of the motor, and the third gear is a two-stage gear, and the number of teeth of the gear on the second gear side is greater than the number of teeth of the gear on the first gear side. Effect of the Invention

[0009] According to the present invention, the medium transport device can more appropriately separate and feed the media. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a medium conveying device 100 according to an embodiment. [Diagram 2] 2 is a diagram for explaining a transport path inside the medium transport device 100. FIG. [Diagram 3] 5A and 5B are schematic diagrams for explaining a driving mechanism for each roller. [Figure 4]5A and 5B are schematic diagrams for explaining a driving mechanism for each roller. [Diagram 5] 1 is a schematic diagram for explaining a support member 109. FIG. [Figure 6] 10A and 10B are schematic diagrams for explaining the operation of the brake roller 113 and the like. [Figure 7] 10A and 10B are schematic diagrams for explaining the state of a brake roller 113 and the like. [Figure 8] 13 is a schematic diagram for explaining the state of an upper guide 107b and the like. FIG. [Figure 9] 1 is a block diagram showing a schematic configuration of a medium conveying device 100. FIG. [Figure 10] FIG. 1 is a diagram showing a schematic configuration of a storage device 160 and a CPU 170. [Figure 11] 10 is a flowchart illustrating an example of the operation of a medium reading process. [Figure 12] FIG. 11 is a schematic diagram for explaining another gear group. [Figure 13] FIG. 13 is a diagram showing a schematic configuration of still another processing circuit 270. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a medium conveying device according to one aspect of the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiment, but extends to the inventions described in the claims and their equivalents.

[0012] 1 is a perspective view showing a medium conveying device 100 configured as an image scanner. The medium conveying device 100 conveys a medium, which is an original document, and captures an image of the medium. The medium is paper, thin paper, thick paper, a card, a booklet, a passport, or the like. The medium conveying device 100 may be a facsimile, a copier, a multifunction printer (MFP, Multifunction Peripheral), or the like. Note that the medium being conveyed may not be an original document, but may be a print target, or the like, and the medium conveying device 100 may be a printer, or the like.

[0013] The medium conveying device 100 includes a lower housing 101, an upper housing 102, a loading platform 103, an ejection platform 104, an operation device 105, and a display device 106. In Fig. 1, an arrow A1 indicates the medium conveying direction. In the following, upstream refers to the upstream side of the medium conveying direction A1, and downstream refers to the downstream side of the medium conveying direction A1. An arrow A2 indicates the width direction perpendicular to the medium conveying direction A1. An arrow A3 indicates the height direction A3 perpendicular to the medium conveying surface.

[0014] Upper housing 102 is disposed in a position covering the top surface of medium transport device 100, and engages with lower housing 101 by a hinge so as to be openable and closable when, for example, a medium is jammed or the inside of medium transport device 100 is cleaned. Placement table 103 engages with lower housing 101 so as to be able to place media to be transported thereon. Discharge table 104 engages with lower housing 101 so as to be able to hold discharged media.

[0015] The operation device 105 has an input device such as a button and an interface circuit for acquiring a signal from the input device, accepts an input operation by a user, and outputs an operation signal according to the input operation by the user. The display device 106 has a display including a liquid crystal, an organic EL (Electro-Luminescence), or the like, and an interface circuit for outputting image data to the display, and displays the image data on the display.

[0016] FIG. 2 is a diagram for explaining a transport path inside the medium transport device 100. As shown in FIG.

[0017] The transport path inside the medium transport device 100 includes a first guide 108, a support member 109, a second guide 110, a medium sensor 111, a feed roller 112, a brake roller 113, a first transport roller 114, a second transport roller 115, a first imaging device 116a, a second imaging device 116b, a first discharge roller 117, and a second discharge roller 118. The number of each roller is not limited to one, and each roller may be provided in multiple numbers.

[0018] The top surface of the lower housing 101 forms a lower guide 107a of the medium transport path, and the bottom surface of the upper housing 102 forms an upper guide 107b of the medium transport path. The lower guide 107a and the upper guide 107b are an example of a transport guide that transports the medium. The upper guide 107b includes a first guide 108 and a second guide 110. In addition, a support member 109 is disposed on the opposite side of the upper guide 107b to the feed roller 112, that is, above the upper guide 107b in the height direction A3.

[0019] The first guide 108 is provided at a position overlapping the feed roller 112 and the brake roller 113 in the medium transport direction A1. The downstream end of the first guide 108 is supported by the upper housing 102 so as to be swingable upward (in the direction of arrow A4 in FIG. 2) according to the thickness of the medium being transported. The first guide 108 abuts against the leading edge of the medium entering the nip position between the feed roller 112 and the brake roller 113 to prevent the leading edge of the medium from lifting up, and also regulates the upper surface of the medium, which has thickness and rigidity.

[0020] The support member 109 is a member that supports the brake roller 113, and the lower surface of the support member 109 forms a part of the upper guide 107b. The upstream end of the support member 109 is supported by the upper housing 102 so as to be swingable upward (in the direction of the arrow A5 in FIG. 2).

[0021] The second guide 110 is provided between the feed roller 112 and the brake roller 113 and the first transport roller 114 and the second transport roller 115 in the medium transport direction A1. The downstream end of the second guide 110 is supported by the upper housing 102 so as to be swingable upward (in the direction of arrow A6 in FIG. 2) according to the thickness of the medium being transported. The second guide 110 abuts against the leading edge of the medium entering the nip position between the first transport roller 114 and the second transport roller 115 to prevent the leading edge of the medium from lifting up, and also regulates the top surface of the medium, which has thickness and rigidity.

[0022] The media sensor 111 is disposed upstream of the feed roller 112 and the brake roller 113. The media sensor 111 has a contact detection sensor, and detects whether or not a medium is placed on the placement table 103. The media sensor 111 generates and outputs a media signal whose signal value changes depending on whether a medium is placed on the placement table 103 or not.

[0023] The feed roller 112 is provided in the lower housing 101, and feeds the media placed on the placement table 103 from the bottom up. The brake roller 113 is an example of a separation roller, and is provided in the upper housing 102, facing the feed roller 112, and separates the media.

[0024] The first imaging device 116a has a line sensor using a CIS (Contact Image Sensor) of a life-size optical system type having imaging elements using CMOS (Complementary Metal Oxide Semiconductor) linearly arranged in the main scanning direction. The first imaging device 116a also has a lens that forms an image on the imaging elements, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging elements. The first imaging device 116a generates and outputs an input image by capturing an image of the surface of the transported medium under the control of a processing circuit described later.

[0025] Similarly, the second imaging device 116b has a line sensor using a CIS of a life-size optical system type having CMOS imaging elements arranged in a line in the main scanning direction. The second imaging device 116b also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The second imaging device 116b generates and outputs an input image by imaging the back side of the transported medium according to control from a processing circuit described later.

[0026] The medium conveying device 100 may have only one of the first imaging device 116a and the second imaging device 116b arranged to read only one side of the medium. Also, instead of a CIS line sensor of an equal-magnification optical system type having a CMOS imaging element, a CIS line sensor of an equal-magnification optical system type having a CCD (Charge Coupled Device) imaging element may be used. Also, a reduction optical system type line sensor having a CMOS or CCD imaging element may be used. Hereinafter, the first imaging device 116a and the second imaging device 116b may be collectively referred to as the imaging device 116.

[0027] The second conveying roller 115, the second imaging device 116b, and the second discharge roller 118 are supported by the upper housing 102 so as to be movable upward according to the thickness of the medium being conveyed.

[0028] The medium placed on the placement table 103 is conveyed between the lower guide 107a and the upper guide 107b in the medium conveying direction A1 by the rotation of the feed roller 112 in the direction of the arrow A11 in FIG. 2, i.e., in the medium feeding direction. The medium conveying device 100 has two operation modes: a separation mode in which the medium is separated and fed when multiple media are placed on the placement table 103, and a non-separation mode in which a medium such as a passport is fed without being separated. When operating in the separation mode, the brake roller 113 rotates in the direction of the arrow A12, i.e., in the opposite direction to the medium feeding direction, during medium conveyance. When multiple media are placed on the placement table 103, only the medium in contact with the feed roller 112 is separated from the media placed on the placement table 103 by the action of the feed roller 112 and the brake roller 113. This limits the conveyance of media other than the separated media (prevention of double feeding). On the other hand, when operating in the non-separation mode, the brake roller 113 rotates in the opposite direction to the arrow A12, that is, in the medium feeding direction, during medium feeding.

[0029] The medium is fed between the first conveyor roller 114 and the second conveyor roller 115 while being guided by the lower guide 107a and the upper guide 107b. The medium is fed between the first imaging device 116a and the second imaging device 116b as the first conveyor roller 114 and the second conveyor roller 115 rotate in the directions of the arrows A13 and A14, respectively. The medium read by the imaging device 116 is discharged onto the discharge tray 104 as the first discharge roller 117 and the second discharge roller 118 rotate in the directions of the arrows A15 and A16, respectively.

[0030] 3 and 4 are schematic diagrams for explaining the drive mechanisms of the feed roller 112, the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and the second discharge roller 118. Fig. 3 is a perspective view of the drive mechanisms of the rollers as seen from the upstream side, and Fig. 4 is a perspective view of the drive mechanisms of the rollers as seen from above and downstream.

[0031] 3 and 4, the drive mechanism for the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and the second discharge roller 118 includes a first motor 151, first to fourth pulleys 141a-d, first to second belts 142a-b, first to thirteenth transmission gears 143a-m, first to seventh shafts 144a-g, and a torque limiter 145. On the other hand, the drive mechanism for the feed roller 112 includes a second motor 152, fifth to sixth pulleys 141e-f, a third belt 142c, fourteenth to sixteenth transmission gears 143n-p, and an eighth shaft 144h.

[0032] The first motor 151 is an example of a motor, and generates a driving force for rotating the brake roller 113, the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and the second discharge roller 118 in response to a control signal from a processing circuit described later. The first motor 151 generates a first driving force for rotating the brake roller 113 in the direction A12 opposite to the medium feeding direction and for rotating the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and the second discharge roller 118 in the medium conveying directions A13 to A16. Note that some or all of the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and the second discharge roller 118 may be rotated by a driving force generated by the second motor 152 or another motor.

[0033] A first pulley 141a is attached to the rotating shaft of the first motor 151, and a first belt 142a is stretched between the first pulley 141a and the pulley portion with the larger outer diameter of the second pulley 141b. A second belt 142b is stretched between the pulley portion with the smaller outer diameter of the second pulley 141b, the pulley portion of the third pulley 141c, and the pulley portion of the fourth pulley 141d.

[0034] The third pulley 141c is attached to the first shaft 144a, and the first discharge roller 117 is further attached to the first shaft 144a. The gear portion of the third pulley 141c is engaged with the first transmission gear 143a. The first transmission gear 143a is attached to the second shaft 144b via a universal joint, and the second discharge roller 118 is further attached to the second shaft 144b. The fourth pulley 141d is attached to the third shaft 144c, and the first conveyor roller 114 is further attached to the third shaft 144c. The gear portion of the fourth pulley 141d is engaged with the second transmission gear 143b. The second transmission gear 143b is attached to the fourth shaft 144d via a universal joint, and the second conveyor roller 115 is further attached to the fourth shaft 144d.

[0035] The second transmission gear 143b is engaged with the third transmission gear 143c. The third transmission gear 143c is engaged with the fourth transmission gear 143d. The fourth transmission gear 143d is engaged with the fifth transmission gear 143e. The fifth transmission gear 143e is engaged with the sixth transmission gear 143f. The sixth transmission gear 143f is engaged with the seventh transmission gear 143g. The seventh transmission gear 143g is attached to the fifth shaft 144e, and the eighth transmission gear 143h is further attached to the fifth shaft 144e. The eighth transmission gear 143h is engaged with the ninth transmission gear 143i, and the ninth transmission gear 143i is engaged with the tenth transmission gear 143j. The tenth transmission gear 143j is attached to the sixth shaft 144f, and the eleventh transmission gear 143k is further attached to the sixth shaft 144f. The eleventh transmission gear 143k is engaged with the twelfth transmission gear 143l, and the twelfth transmission gear 143l is engaged with the thirteenth transmission gear 143m. The thirteenth transmission gear 143m is attached to a seventh shaft 144g, and a brake roller 113 is further attached to the seventh shaft 144g.

[0036] A torque limiter 145 is provided on the seventh shaft 144g, which is the rotation axis of the brake roller 113, between the twelfth transmission gear 143l and the brake roller 113. That is, the torque limiter 145 is disposed on a driving force transmission path from the first motor 151 to the brake roller 113, and controls the load on the brake roller 113. Since there is no gear train between the torque limiter 145 and the brake roller 113, fluctuations in the separation force applied to the brake roller 113 due to manufacturing errors of each part and the like are suppressed. Therefore, the medium conveying device 100 can separate the medium with high accuracy regardless of manufacturing errors of each part.

[0037] The limit value of the torque limiter 145 is set to a value such that when there is one medium, the rotational force via the torque limiter 145 is cut off, and when there are multiple media, the rotational force via the torque limiter 145 is transmitted. As a result, when only one medium is transported, the brake roller 113 does not rotate according to the first driving force, but follows the feed roller 112. On the other hand, when multiple media are transported, the brake roller 113 rotates in the direction opposite to the medium feeding direction A12, and separates the medium in contact with the feed roller 112 from the other media, thereby preventing double feeding. At this time, the outer circumferential surface of the brake roller 113 may apply a force in the direction opposite to the medium feeding direction A12 to the medium while stopped and not rotating in the direction opposite to the medium feeding direction A12.

[0038] The first to fourth pulleys 141a-d, the first and second belts 142a-b, the first to thirteenth transmission gears 143a-m, and / or the fifth to seventh shafts 144e-g are an example of a transmission member for transmitting the driving force generated by the first motor 151 to the torque limiter 145. Note that the transmission member may be composed of only gears or only pulleys and belts.

[0039] The second motor 152 generates a driving force for rotating the feed roller 112 in response to a control signal from a processing circuit, which will be described later. The second motor 152 generates a second driving force for rotating the feed roller 112 in the medium feed direction A11.

[0040] A fifth pulley 141e is attached to the rotating shaft of the second motor 152, and a third belt 142c is stretched between the fifth pulley 141e and the pulley portion of the sixth pulley 141f. A gear portion of the sixth pulley 141f is engaged with a fourteenth transmission gear 143n, which is engaged with a fifteenth transmission gear 143o, which is engaged with a sixteenth transmission gear 143p. The sixteenth transmission gear 143p is attached to an eighth shaft 144h, and the feed roller 112 is further attached to the eighth shaft 144h.

[0041] Moreover, one end of a spring 109a, the other end of which is supported by the upper housing 102, is attached to the upper surface of the support member 109. The support member 109 and the brake roller 113 are biased downward in the height direction A3, i.e., toward the feed roller 112 side, by the spring 109a. The spring 109a is an example of a pressing member that presses the brake roller 113 toward the feed roller 112 side. Rubber or the like may be used as the pressing member instead of the spring 109a. Hereinafter, the brake roller 113, the support member 109, the eleventh to thirteenth transmission gears 143k-m, the seventh shaft 144g, and the torque limiter 145 may be collectively referred to as a brake roller unit. The brake roller unit is an example of a unit.

[0042] The operation of each roller and its drive mechanism will now be described.

[0043] When the first motor 151 generates the first driving force, the first pulley 141a rotates in the direction of the arrow B1, and the second to fourth pulleys 141b-d rotate in the direction of the arrow B1 accordingly. The first to seventh transmission gears 143a-g rotate in the directions of the arrows B2-B8, the eighth to tenth transmission gears 143h-j rotate in the directions of the arrows B8-B10, and the eleventh to thirteenth transmission gears 143k-m rotate in the directions of the arrows B10-B12. As a result, the brake roller 113 rotates in the opposite direction A12 to the medium feeding direction by the first driving force from the first motor 151 together with the seventh shaft 144g which is the rotation axis.

[0044] The eleventh transmission gear 143k is an example of a first gear, and rotates in response to a first driving force generated by the first motor 151. The thirteenth transmission gear 143m is an example of a second gear, and is provided on the seventh shaft 144g, which is the rotation shaft of the brake roller 113. The twelfth transmission gear 143l is an example of a third gear, and is provided between the eleventh transmission gear 143k and the thirteenth transmission gear 143m.

[0045] Furthermore, as the third pulley 141c rotates in the direction of arrow B1, the first discharge roller 117 rotates in the medium transport direction A15. As the first transmission gear 143a rotates in the direction of arrow B2, the second discharge roller 118 rotates in the medium transport direction A16. As the fourth pulley 141d rotates in the direction of arrow B1, the first transport roller 114 rotates in the medium transport direction A13. As the second transmission gear 143b rotates in the direction of arrow B3, the second transport roller 115 rotates in the medium transport direction A14.

[0046] On the other hand, when the second motor 152 generates the second driving force, the fifth pulley 141e rotates in the direction of the arrow B13, and accordingly the sixth pulley 141f rotates in the direction of the arrow B13. In addition, the fourteenth to sixteenth transmission gears 143n-p rotate in the directions of the arrows B14-B16, respectively, causing the feed roller 112 to rotate in the medium feed direction A11.

[0047] Fig. 5 is a schematic diagram for explaining the support member 109. Fig. 5 is a perspective view of the drive mechanism of the support member 109 and the brake roller 113, seen from the upstream side. In Fig. 5, the support member 109 is indicated by a dotted line.

[0048] The support member 109 is formed of resin, metal, or the like. The support member 109 has an upper surface 109b, a first side surface 109c, and a second side surface 109d. The support member 109 supports the eleventh to thirteenth transmission gears 143k-m, the torque limiter 145, and the brake roller 113. The above-mentioned spring 109a is attached to the upper surface 109b. The sixth shaft 144f to which the eleventh transmission gear 143k is attached and the shaft to which the twelfth transmission gear 143l is attached are attached to the first side surface 109c. In addition, both ends of the seventh shaft 144g to which the thirteenth transmission gear 143m, the torque limiter 145, and the brake roller 113 are attached are attached to the first side surface 109c and the second side surface 109d. A protrusion 109e is provided on the second side surface 109d coaxially with the sixth shaft 144f, and the support member 109 is attached to the upper housing 102 to be rotatable (swingable) about the protrusion 109e and the sixth shaft 144f as a rotation (swing) axis.

[0049] In this manner, the support member 109 is supported by the upper housing 102 to be swingable (rotatable) about the sixth shaft 144f, which is the axis of the eleventh transmission gear 143k, as a rotation axis, and supports the brake roller 113 to be swingable.

[0050] FIG. 6 is a schematic diagram for explaining the operations of the eleventh to thirteenth transmission gears 143k-m, the support member 109 and the brake roller 113. As shown in FIG.

[0051] As described above, when the first motor 151 generates the first driving force, the eleventh to thirteenth transmission gears 143k-m rotate in the directions of the arrows B10-B12, respectively, and the brake roller 113 rotates in the direction A12 opposite to the medium feeding direction. The eleventh to thirteenth transmission gears 143k-m and the brake roller 113 are supported by the support member 109 that is provided so as to be rotatable (swingable) around the sixth shaft 144f to which the eleventh transmission gear 143k is attached. Therefore, when the eleventh transmission gear 143k rotates in the direction of the arrow B10, a force in the direction of the arrow A5 is applied to the twelfth transmission gear 143l. As a result, a force that rotates around the sixth shaft 144f in the direction of the arrow A5 is applied to the first side surface 109c to which the twelfth transmission gear 143l is attached. As a result, a force is applied to the support member 109 to rotate it around the sixth shaft 144f in the direction of the arrow A5, and a force is applied to the brake roller 113 in a direction away from the feed roller 112 (the direction of the arrow A5).

[0052] That is, the brake roller unit is supported swingably on the sixth shaft 144f so that a predetermined force acts on the brake roller 113 in a direction separating the brake roller 113 from the feed roller 112 when the first driving force is transmitted from the eleventh to thirteenth transmission gears 143k-m. The eleventh transmission gear 143k rotates in a direction (the direction of the arrow B10) that generates a force that separates the brake roller 113 from the feed roller 112 by the rotation of the first motor 151. In addition, the support member 109 and the brake roller 113 are pressed toward the feed roller 112 by the spring 109a. This allows the brake roller 113 to feed the medium without separating from the feed roller 112.

[0053] The force acting on the brake roller 113 will now be described.

[0054] As shown in FIG. 6, the 12th transmission gear 143l is a two-stage gear, and the number of teeth of the gear on the 13th transmission gear 143m side is greater than the number of teeth of the gear on the 11th transmission gear 143k side. That is, the 12th transmission gear 143l operates as a reduction gear that reduces the rotation from the 11th transmission gear 143k and transmits it to the 13th transmission gear 143m. The 12th transmission gear 143l reduces the first driving force of the first motor 151 from the 11th transmission gear 143k to the 13th transmission gear 143m and transmits it. Each gear of the 12th transmission gear 143l is formed of an integral member. Note that each gear of the 12th transmission gear 143l may be formed integrally with separate members.

[0055] First to third forces F1 to F3 act on the brake roller 113. The first force F1 is a force that causes the brake roller 113 to bite into the feed roller 112, which is generated by a load (separation torque) applied to the brake roller 113 in the medium transport direction A1 when the brake roller 113 tries to rotate in the direction A12 opposite to the medium feed direction. That is, the first force F1 is generated by limiting the torque that causes the brake roller 113 to rotate in the direction A12 opposite to the rotation direction of the feed roller 112 by the torque limiter 145. The first force F1 is a force that presses the brake roller 113 toward the feed roller 112 by the torque limiter 145, and the brake roller 113 is pressed toward the feed roller 112 by the first force F1.

[0056] The second force F2 is generated by the gear transmission torque of the gear group including the eleventh to thirteenth transmission gears 143k-m, and is a force that tends to lift up the brake roller 113. That is, the second force F2 is a force that separates the brake roller 113 from the feed roller 112 by the eleventh transmission gear 143k.

[0057] The third force F3 is a pressing force by which the spring 109a presses the brake roller 113 toward the feed roller 112. The third force F3 is a static force determined according to the spring constant of the spring 109a, etc. That is, the third force F3 is a force by which the spring 109a presses the brake roller 113 toward the feed roller 112.

[0058] A force equal to the sum of the first force F1 and the third force F3 minus the second force F2 acts on the brake roller 113 in the direction in which the brake roller 113 presses the feed roller 112. In order for the two sheets of paper to be separated, the separation force acting on the two sheets of paper (the back load caused by the brake roller 113) must be greater than the friction force between the two sheets of paper. The magnitude of the separation force acting on the two sheets of paper is calculated by dividing the limit value of the torque limiter 145 by the radius of the brake roller 113. On the other hand, the magnitude of the friction force between the two sheets of paper is calculated by multiplying the friction coefficient between the two sheets of paper by the force acting in the direction in which the brake roller 113 presses the feed roller 112 described above. In other words, the greater the force acting in the direction in which the brake roller 113 presses the feed roller 112, the smaller the friction coefficient of the separable sheets of paper, making it easier for multiple feeding of media to occur.

[0059] For example, the second force F2 can be increased by making the eleventh transmission gear 143k, which is the pivot shaft of the brake roller 113, sufficiently large (increasing the number of teeth). However, when trying to make the eleventh transmission gear 143k large, it is necessary to move the rotation fulcrum of the eleventh transmission gear 143k far away from the medium transport path so that the eleventh transmission gear 143k does not protrude into the medium transport path. When the distance between the rotation fulcrum of the eleventh transmission gear 143k and the medium transport path increases, the first force F1 increases, and as a result, it becomes difficult to reduce the force acting in the direction in which the brake roller 113 presses the feed roller 112.

[0060] The second force F2 can also be increased by making the thirteenth transmission gear 143m attached to the seventh shaft 144g that supports the brake roller 113 sufficiently small (reducing the number of teeth). However, making the thirteenth transmission gear 143m small reduces the tooth surface strength of the thirteenth transmission gear 143m, making the thirteenth transmission gear 143m more susceptible to wear, and as a result, the device life (or component life) of the medium conveying device 100 is shortened.

[0061] The medium conveying device 100 uses a reduction gear as the twelfth transmission gear 143l, which is an idler gear provided between the eleventh transmission gear 143k and the thirteenth transmission gear 143m. This allows the medium conveying device 100 to increase the second force F2 without making the eleventh transmission gear 143k sufficiently large or the thirteenth transmission gear 143m sufficiently small. As a result, the medium conveying device 100 can reduce the force acting in the direction in which the brake roller 113 presses the feed roller 112, and can suppress the occurrence of double feeding of media.

[0062] As described above, the third force F3 is a static force determined according to the spring constant of the spring 109a and the like. On the other hand, the first force F1 and the second force F2 are dynamic forces that occur with the feeding and separation of the medium. Therefore, the first force F1 and the second force F2 fluctuate slightly due to slight vibrations caused by unevenness formed on the surfaces (rubber) of the feeding roller 112 and the brake roller 113, or the engagement timing of the members inside the torque limiter 145, and the like. The smaller the magnitude of the first force F1 and the second force F2, the more stable the applied pressure on the brake roller 113 is maintained, and the medium is separated stably. However, since the magnitudes of the first force F1 and the second force F2 are determined by the structure of the unit, it is difficult to reduce the magnitudes of the first force F1 and the second force F2 themselves.

[0063] However, if the difference between the magnitude of the first force F1 and the magnitude of the second force F2 is small, the first force F1 and the second force F2 cancel each other out, the pressure applied to the brake roller 113 is kept stable, and the medium is stably separated. Usually, the magnitude of the first force F1 generated by the separation torque is sufficiently larger than the magnitude of the second force F2 generated by the gear transmission torque. As described above, the medium conveying device 100 can make the second force F2 sufficiently large, approximately the same as the first force F1, by providing a reduction gear between the eleventh transmission gear 143k and the thirteenth transmission gear 143m.

[0064] The first force F1 changes depending on the positional relationship between the nip position between the feed roller 112 and the brake roller 113 and the swing fulcrum of the brake roller 113. The first force F1 is calculated by the following formula (1). F1 = {(T / R) × H} / A (1) Here, T is the limit value of the torque limiter 145. R is the radius of the brake roller 113. H is the distance between the nip position of the feed roller 112 and the brake roller 113 in a direction perpendicular to the nip surface of the feed roller 112 and the brake roller 113 and the rotation center of the eleventh transmission gear 143k (see FIG. 6). A is the distance between the nip position of the feed roller 112 and the brake roller 113 in a direction parallel to the nip surface of the feed roller 112 and the brake roller 113 and the rotation center of the eleventh transmission gear 143k (see FIG. 6).

[0065] On the other hand, the second force F2 changes according to the gear train disposed between the swing fulcrum of the brake roller 113 and the rotation fulcrum of the brake roller 113. The second force F2 is calculated by the following formula (2). F2 = {T × (Z1 / Z2) × G} / A (2) Here, Z1 is the number of teeth of the eleventh transmission gear 143k, Z2 is the number of teeth of the thirteenth transmission gear 143m, and G is the gear ratio of the number of teeth of the gear on the thirteenth transmission gear 143m side to the number of teeth of the gear on the eleventh transmission gear 143k side in the twelfth transmission gear 143l.

[0066] The twelfth transmission gear 143l is provided so that the difference between the first force F1 and the second force F2 is equal to or less than a predetermined value. Also, the twelfth transmission gear 143l is provided so that the first force F1 is equal to or greater than the second force F2 so that the brake roller 113 does not lift up relative to the feed roller 112. That is, the gear ratio G of the twelfth transmission gear 143l is set so as to satisfy the following formula (3). 0≦[{(T / R)×H} / A]-[{T×(Z1 / Z2)×G} / A]≦D (3) Here, D is a predetermined value, and is set to, for example, 100 [gf] (0.98 [N]).

[0067] For example, when the limit value T of the torque limiter 145 is 500 [gfcm], the radius R of the brake roller 113 is 13.5 [mm], the distance H is 25.6 [mm], and the distance A is 31.1 [mm], the first force F1 is 304.8 [gf]. Furthermore, when the number of teeth Z1 of the eleventh transmission gear 143k is 28, and the number of teeth Z2 of the thirteenth transmission gear 143m is 24, the second force F2 is 187.6×G [gf]. In this case, the gear ratio G of the twelfth transmission gear 143l is set to 1.09 or more and 1.62 or less so as to satisfy the formula (3). It is preferable that the gear ratio G of the twelfth transmission gear 143l is set to 1.05 or more and 1.80 or less, with a margin considering the component tolerance of the medium conveying device 100 and the like.

[0068] FIG. 7 is a schematic diagram for explaining the state of the brake roller 113 and the support member 109 when a medium having a thickness and rigidity such as a passport is transported.

[0069] In the example shown in Fig. 7, the passport M is being fed. As described above, the support member 109 is supported by the upper housing 102 so as to be able to swing. As shown in Fig. 7, since the passport M has thickness and rigidity, the brake roller 113 is pushed up by the passport M, and accordingly, the seventh shaft 144g which is the rotation axis of the brake roller 113 is pushed up. Since the seventh shaft 144g is attached to the upstream end of the support member 109 and the downstream end of the support member 109 is supported by the upper housing 102 so as to be able to swing with the sixth shaft 144f and the protrusion 109e as the swing axis, the support member 109 swings in the direction of the arrow A5.

[0070] FIG. 8 is a schematic diagram for explaining the states of the upper guide 107b, the second conveyor roller 115, the second imaging device 116b, and the second discharge roller 118 when a medium having thickness and rigidity such as a passport is conveyed.

[0071] In the example shown in Fig. 8, a passport M is being fed. As described above, the first guide 108 and the second guide 110 are supported by the upper housing 102 so as to be able to swing. As shown in Fig. 8, since the passport M has thickness and rigidity, the first guide 108 and the second guide 110 are pushed up by the passport M and swing in the directions of the arrows A4 and A6, respectively. Also, as described above, the second conveying roller 115, the second imaging device 116b, and the second discharge roller 118 are supported by the upper housing 102 so as to be able to move upward in the height direction A3, and therefore are pushed up by the passport M and move upward.

[0072] In this manner, the lower guide 107a and the upper guide 107b are provided so as to be able to transport a passport. A brake roller unit including the brake roller 113, the support member 109, the eleventh to thirteenth transmission gears 143k-m, and the torque limiter 145 is disposed on the opposite side of the feed roller 112 with the lower guide 107a and the upper guide 107b in between. In order to ensure the transport of a thick passport, the sixth shaft 144f, which is the pivot shaft of the brake roller 113, is disposed at a position sufficiently distant from the lower guide 107a. For example, the distance between the center of the sixth shaft 144f and the lower guide 107a in the height direction A3 is set to 18 mm or more.

[0073] As described above, the first force F1 increases as the distance between the rotation fulcrum of the eleventh transmission gear 143k and the medium transport path increases. The medium transport device 100 increases the second force F2 by using a reduction gear as the twelfth transmission gear 143l, which is an idler gear provided between the eleventh transmission gear 143k and the thirteenth transmission gear 143m. This allows the medium transport device 100 to transport a medium having a thickness such as a passport well, while separating a plurality of media such as paper that are transported together. In other words, the medium transport device 100 can achieve both the transportability of a thick medium and the separability of media that are transported together.

[0074] FIG. 9 is a block diagram showing a schematic configuration of the medium conveying device 100. As shown in FIG.

[0075] In addition to the components described above, the medium conveying device 100 further includes an interface device 153, a storage device 160, a processing circuit 170, and the like.

[0076] The interface device 153 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (not shown, for example, a personal computer, a mobile information terminal, etc.) to transmit and receive input images and various information. Also, instead of the interface device 153, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals through a wireless communication line in accordance with a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network).

[0077] The storage device 160 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. The storage device 160 also stores computer programs, databases, tables, and the like used for various processes of the medium conveying device 100. The computer programs may be installed in the storage device 160 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or the like.

[0078] The processing circuit 170 operates based on a program previously stored in the storage device 160. The processing circuit is, for example, a CPU (Central Processing Unit). The processing circuit 170 may be, for example, a DSP (digital signal processor), an LSI (large scale integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array).

[0079] The processing circuit 170 is connected to the operation device 105, the display device 106, the medium sensor 111, the imaging device 116, the first motor 151, the second motor 152, the interface device 153, the storage device 160, etc., and controls each of these components. The processing circuit 170 performs drive control of the first motor 151 and the second motor 152, image capture control of the imaging device 116, etc., controls the transportation of the medium, generates an input image, and transmits it to the information processing device via the interface device 153.

[0080] FIG. 10 is a diagram showing a schematic configuration of the storage device 160 and the processing circuit 170. As shown in FIG.

[0081] 10, the storage device 160 stores a control program 161, an image acquisition program 162, and the like. Each of these programs is a functional module implemented by software that runs on a processor. The processing circuitry 170 reads each program stored in the storage device 160 and operates according to the read program. In this way, the processing circuitry 170 functions as a control unit 171 and an image acquisition unit 172.

[0082] FIG. 11 is a flowchart showing an example of the operation of the medium reading process of the medium conveying device 100.

[0083] An example of the operation of the medium reading process of the medium conveying device 100 will be described below with reference to the flowchart shown in Fig. 11. The flow of the operation described below is executed mainly by the processing circuit 170 in cooperation with each element of the medium conveying device 100 based on a program previously stored in the storage device 160. The flow of the operation shown in Fig. 11 is executed periodically.

[0084] First, the control unit 171 waits until a user inputs an instruction to read a medium using the operation device 105 and an operation signal instructing to read a medium is received from the operation device 105 (step S101).

[0085] Next, control unit 171 acquires a medium signal from medium sensor 111, and determines whether or not a medium is placed on placement table 103 based on the acquired medium signal (step S102).

[0086] If no medium is placed on the placement table 103, the control unit 171 returns the process to step S101 and waits until a new operation signal is received from the operation device 105.

[0087] On the other hand, when a medium is placed on the placement table 103, the control unit 171 drives the first motor 151 and the second motor 152 (step S103). The control unit 171 causes the first motor 151 to generate a first driving force. As a result, the control unit 171 rotates the brake roller 113 in the direction A12 opposite to the medium feeding direction, and rotates the first conveyor roller 114, the second conveyor roller 115, the first discharge roller 117, and the second discharge roller 118 in the medium conveying directions A13 to A16. The control unit 171 also causes the second motor 152 to generate a second driving force, and rotates the feed roller 112 in the medium feeding direction A11. As a result, the control unit 171 executes feeding and conveying of the medium.

[0088] Next, the image acquisition unit 172 causes the imaging device 116 to start capturing an image of the medium, and acquires an input image from the imaging device 116 (step S104).

[0089] Next, the image acquisition unit 172 transmits the input image to the information processing device via the interface device 153 (step S105).

[0090] Next, control unit 171 determines whether or not a medium remains on mounting table 103 based on a medium signal obtained from medium sensor 111 (step S106). If a medium remains on mounting table 103, control unit 171 returns the process to step S104, and repeats the processes of steps S104 to S106.

[0091] On the other hand, if there are no media remaining on the mounting table 103, the control unit 171 stops the first motor 151 and the second motor 152 (step S107), and ends the series of steps.

[0092] As described above in detail, the medium conveying device 100 provides the twelfth transmission gear 143l, which is a reduction gear, between the eleventh transmission gear 143k and the thirteenth transmission gear 143m. This allows the medium conveying device 100 to set the separating force generated by the rotation of the eleventh transmission gear 143k to an appropriate value relative to the pressing force generated by the torque limiter 145. This allows the medium conveying device 100 to apply an appropriate force to the medium when separating and feeding the medium, making it possible to more appropriately separate and feed the medium.

[0093] FIG. 12 is a schematic diagram for explaining a gear group of a medium conveying device according to another embodiment.

[0094] In this embodiment, a support member 209 is used instead of the support member 109, and sixth to seventh shafts 244f-g are used instead of the sixth to seventh shafts 144f-144g. Also, eleventh to thirteenth transmission gears 243k-m are used instead of the eleventh to thirteenth transmission gears 143k-m. Also, a seventeenth transmission gear 243q is provided between the eleventh transmission gear 243k and the twelfth transmission gear 243l, and an eighteenth transmission gear 243r is provided between the twelfth transmission gear 243l and the thirteenth transmission gear 243m. The support member 209, the sixth to seventh shafts 244f-g, and the eleventh to thirteenth transmission gears 243k-m have the same configurations as the support member 109, the sixth to seventh shafts 144f-g, and the eleventh to thirteenth transmission gears 143k-m, respectively.

[0095] The seventeenth transmission gear 243q is attached to the support member 209 so as to engage with the eleventh transmission gear 243k and the twelfth transmission gear 243l. The eighteenth transmission gear 243r is attached to the support member 209 so as to engage with the twelfth transmission gear 243l and the thirteenth transmission gear 243m.

[0096] The number of gears disposed between the sixth shaft 244f which is the rotation shaft of the eleventh transmission gear 243k and the seventh shaft 244g which is the rotation shaft of the brake roller 113 is not limited to 3 or 5, and may be any odd number equal to or greater than 3. As a result, the brake roller 113 rotates in the same direction A12 as the rotation direction B10 of the eleventh transmission gear 243k, while a force is applied to the brake roller 113 in the same direction A5 as the rotation direction B10 of the eleventh transmission gear 243k.

[0097] Furthermore, the twelfth transmission gear 243l, which is a reduction gear, may be disposed at any position, such as a position where it engages with the eleventh transmission gear 243k or a position where it engages with the thirteenth transmission gear 243m. This allows the medium conveying device to increase the second force F2 without making the eleventh transmission gear 243k sufficiently large or the thirteenth transmission gear 243m sufficiently small.

[0098] As described above in detail, the medium conveying device is able to separate and feed the medium more appropriately even when the number of gears arranged between the rotation shaft of the 11th transmission gear 243k and the rotation shaft of the brake roller 113 is an odd number equal to or greater than five.

[0099] 13 is a diagram showing a schematic configuration of a processing circuit 270 in a medium conveying device according to yet another embodiment. The processing circuit 270 is used in place of the processing circuit 170 of the medium conveying device 100, and executes the medium reading process and the setting process in place of the CPU 170. The processing circuit 270 has a control circuit 271, an image acquisition circuit 272, and the like. Each of these components may be formed of an independent integrated circuit, microprocessor, firmware, and the like.

[0100] The control circuit 271 is an example of a control unit, and has the same functions as the control unit 171. The control circuit 271 receives an operation signal from the operation device 105 and a medium signal from the medium sensor 111. The control circuit 271 drives the first motor 151 and the second motor 152 in response to each of the received signals.

[0101] The image acquisition circuit 272 is an example of an image acquisition unit, and has the same function as the image acquisition unit 172. The image acquisition circuit 272 receives an input image from the imaging device 116, stores it in the storage device 160, and transmits it to the information processing device via the interface device 153.

[0102] As described above in detail, the medium conveying device is now able to more appropriately separate and feed the media even when the processing circuit 270 is used. [Explanation of symbols]

[0103] 100 medium conveying device, 107a lower guide, 107b upper guide, 109a spring, 112 feed roller, 113 brake roller, 143k eleventh transmission gear, 143l twelfth transmission gear, 143m thirteenth transmission gear, 145 torque limiter, 151 first motor

Claims

1. A feed roller for feeding the medium; a separation roller disposed opposite the feed roller and configured to separate a medium; a torque limiter provided on a rotation shaft of the separation roller; a motor that generates a driving force for rotating the separation roller in a direction opposite to the medium feeding direction; a unit including a first gear that rotates in response to a driving force generated by the motor, a second gear provided on a rotation shaft of the separation roller, and a third gear provided between the first gear and the second gear, the unit being supported so as to be swingable about the shaft of the first gear as a rotation shaft; the torque limiter limits the torque that rotates the separation roller in a direction opposite to the rotation direction of the feed roller, and a force is generated by the torque limiter, whereby the separation roller is pressed toward the feed roller; the first gear rotates in a direction in which a force is generated to separate the separation roller from the feed roller by the rotation of the motor, The third gear is a two-stage gear, and the number of teeth of the gear on the second gear side is greater than the number of teeth of the gear on the first gear side. the third gear is provided so that a difference between a force with which the torque limiter presses the separation roller toward the feed roller and a force with which the first gear separates the separation roller from the feed roller is 100 gf or less. A medium transport device comprising:

2. The medium transport device according to claim 1 , wherein the number of gears disposed between the rotation shaft of the first gear and the rotation shaft of the separation roller is an odd number.

3. The medium transport device according to claim 1 , further comprising a pressing member that presses the separation roller against the feed roller.

4. The passport-transporting device further includes a transport guide capable of transporting the passport.

4. The medium transport device according to claim 1, wherein the unit is disposed on an opposite side of the transport guide from the feed roller.

Images