Medium transport device

Abstract

To provide a medium transport device in which a holder for holding the roller is provided in a swingable manner to reduce the size of the device.SOLUTION: The medium transport device includes: a roller rotatably arranged around a rotating shaft; a drive shaft mechanically connected to the rotating shaft; a holder that holds the rotating shaft and the drive shaft and is rotatably arranged around a swinging shaft; a drive source; and a drive connection portion that can transmit driving force from the drive source to the drive shaft, the distance between the drive shaft and the swinging shaft being smaller than the distance between the rotating shaft and the swinging shaft.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a media transport device. [Background technology]

[0002] In general, a medium transport device such as a scanner that captures an image while transporting a medium is required to transport media of various thicknesses. In some medium transport devices, a holder that holds a roller is provided so as to be able to swing so that the roller moves according to the thickness of the medium being transported.

[0003] A paper feeder in which a brake roller is provided in a brake roller unit has been disclosed (see Patent Document 1). In this paper feeder, the brake roller unit rotates around a fulcrum, so the braking force transmission mechanism uses a universal joint. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-206571 A Summary of the Invention [Problem to be solved by the invention]

[0005] In media handling devices, it is desirable to reduce the size of the device.

[0006] An object of the present invention is to reduce the size of a medium transport device in which a holder for holding a roller is provided so as to be able to swing. [Means for solving the problem]

[0007] A media transport device according to one aspect of the present invention comprises a roller rotatably arranged around a rotating shaft, a drive shaft mechanically connected to the rotating shaft, a holder that holds the rotating shaft and the drive shaft and is rotatably arranged around a swinging shaft, a drive source, and a drive connection portion capable of transmitting driving force from the drive source to the drive shaft, wherein the distance between the drive shaft and the swinging shaft is smaller than the distance between the rotating shaft and the swinging shaft. Effect of the Invention

[0008] According to the present invention, in a medium transport device in which a holder for holding a roller is provided so as to be able to swing, it is possible to reduce the size of the device. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view illustrating a medium transport device according to an embodiment. [Diagram 2] 2 is a diagram for explaining a transport path inside a medium transport device according to an embodiment; FIG. [Diagram 3] 5A and 5B are schematic diagrams for explaining a drive mechanism for a separation roller and the like according to an embodiment. [Figure 4] 5A and 5B are schematic diagrams for explaining the positional relationship of a separation roller and the like according to an embodiment. [Diagram 5] 5A to 5C are schematic diagrams for explaining the operation of a separation roller and the like according to an embodiment. [Figure 6] 4 is a schematic diagram of the periphery of a separation roller and the like according to an embodiment, viewed from the upstream side; FIG. [Figure 7] 4 is a schematic diagram of the periphery of a separation roller and the like according to an embodiment, viewed from the upstream side; FIG. [Figure 8] 1 is a block diagram showing a schematic configuration of a medium conveying device according to an embodiment; [Figure 9] FIG. 1 is a diagram showing a schematic configuration of a storage device and a processing circuit according to an embodiment. [Figure 10] 10 is a flowchart illustrating an example of an operation of a medium reading process according to an embodiment. [Figure 11] 13 is a diagram showing a schematic configuration of a processing circuit in another medium conveying device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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.

[0011] FIG. 1 is a perspective view showing a medium conveying device configured as an image scanner according to one embodiment. The medium conveying device 100 conveys a medium, which is an original, and captures an image. The medium is paper, thin paper, thick paper, a card, a booklet, or the like. Booklets include passports having a thickness of, for example, 7 mm. 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 but may be a print target, or the like, and the medium conveying device 100 may be a printer, or the like.

[0012] The medium conveying device 100 includes a lower housing 101, an upper housing 102, a placement table 103, a discharge table 104, an operation device 105, a display device 106, and the like.

[0013] The upper housing 102 is disposed in a position that covers the top surface of the medium conveying device 100, and engages with the lower housing 101 by a hinge so that it can be opened and closed when the medium is jammed or when the inside of the medium conveying device 100 is cleaned.

[0014] The placement stage 103 is engaged with the lower housing 101 so that the medium to be transported can be placed thereon. The ejection stage 104 is engaged with the upper housing 102 so that the ejected medium can be held thereon. The ejection stage 104 may be engaged with the lower housing 101.

[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] 1, arrow A1 indicates the medium transport direction, arrow A2 indicates the width direction perpendicular to the medium transport direction, and arrow A3 indicates the height direction perpendicular to the medium transport direction and the width direction. In the following, upstream refers to the upstream side of the medium transport direction A1, and downstream refers to the downstream side of the medium transport direction A1.

[0017] FIG. 2 is a diagram for explaining a transport path inside the medium transport device according to one embodiment.

[0018] The transport path inside the medium transport device 100 includes a medium sensor 111, a feed roller 112, a separation roller 113, a first transport roller 114, a second transport roller 115, an imaging device 116, a third transport roller 117, and a fourth transport roller 118. The number of each roller is not limited to one, and each roller may be provided in multiple numbers. In this case, the rollers are arranged side by side at intervals in the width direction A2.

[0019] The medium conveying device 100 has a so-called straight path. The upper surface of the lower housing 101 forms a lower guide 107a of the medium conveying path, and the lower surface of the upper housing 102 forms an upper guide 107b of the medium conveying path. The lower guide 107a is an example of a guide portion that guides the medium.

[0020] The media sensor 111 is disposed upstream of the feed roller 112 and the separation 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 first media signal whose signal value changes depending on whether or not a medium is placed on the placement table 103. Note that the media sensor 111 is not limited to a contact detection sensor, and any other sensor capable of detecting the presence or absence of a medium, such as a light detection sensor, may be used as the media sensor 111.

[0021] 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 separation roller 113 is an example of a roller. The separation roller 113 is a so-called brake roller or retard roller, and is provided in the upper housing 102, and is disposed opposite the feed roller 112. The feed roller 112 and the separation roller 113 function as a separation unit that separates the media.

[0022] The first transport roller 114 and the second transport roller 115 are disposed downstream of the feed roller 112 and the separation roller 113 so as to face each other, and transport the medium fed by the feed roller 112 and the separation roller 113 to the imaging device 116.

[0023] The imaging device 116 is disposed downstream of the first conveyor roller 114 and the second conveyor roller 115 and upstream of the third conveyor roller 117 and the fourth conveyor roller 118. The imaging device 116 includes a first imaging device 116a and a second imaging device 116b. The first imaging device 116a and the second imaging device 116b are disposed near the medium conveyor path and facing each other across the conveyor path.

[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 captures an image of the surface of the medium being transported, generates an input image, and outputs it.

[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 A / D converts the electrical signal output from the imaging element. The second imaging device 116b captures the back side of the medium being transported to generate an input image and output it.

[0026] The medium conveying device 100 may be arranged with only one of the first imaging device 116a and the second imaging device 116b, and may 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.

[0027] The third conveyor roller 117 and the fourth conveyor roller 118 are disposed downstream of the imaging device 116 and facing each other, and discharge the medium conveyed by the first conveyor roller 114 and the second conveyor roller 115 onto the discharge table 104.

[0028] The medium placed on the mounting table 103 is transported between the lower guide 107a and the upper guide 107b in the medium transport direction A1 by the rotation of the feed roller 112 in the direction of the arrow A4 in Fig. 2. The separation roller 113 rotates in the direction of the arrow A5 in Fig. 2 or stops when transporting the medium. When multiple media are placed on the mounting table 103, the feed roller 112 and the separation roller 113 function to separate only the media placed on the mounting table 103 that is in contact with the feed roller 112. This limits the transport of media other than the separated media (preventing double 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 by the first conveyor roller 114 and the second conveyor roller 115 rotating in the directions of the arrows A6 and A7 in Fig. 2, respectively. The medium read by the imaging device 116 is discharged onto the discharge tray 104 by the third conveyor roller 117 and the fourth conveyor roller 118 rotating in the directions of the arrows A8 and A9 in Fig. 2, respectively.

[0030] 3 is a schematic diagram for explaining a drive mechanism for a feed roller and a separation roller according to an embodiment of the present invention, and is a perspective view of the drive mechanism for each roller as viewed from the upstream side.

[0031] 3, the medium conveying device 100 has a separation roller shaft 113a and a feed roller shaft 112a. Furthermore, the medium conveying device 100 has a holder 121, a first driving source 122, a first gear 123, an electromagnetic clutch 124, a second gear 125, a first shaft 126, a drive connecting portion 127, a second shaft 128, a third gear 129, a fourth gear 130, a fifth gear 131, a torque limiter 132, and a sixth gear 133.

[0032] The separation roller 113 is provided so as to be rotatable about a separation roller shaft 113a. The separation roller shaft 113a is an example of a rotation shaft.

[0033] The holder 121 is a unit that supports the separation roller 113 so that it can swing. The holder 121 includes a first plate member 121a, a second plate member 121b, and a third plate member 121c. The first plate member 121a is disposed above the separation roller 113. The second plate member 121b is disposed on the side of the separation roller 113 so that one end of the first plate member 121a in the width direction A2 is connected to the upper end of the second plate member 121b. The third plate member 121c is disposed on the side of the separation roller 113 opposite to the second plate member 121b so that the other end of the first plate member 121a in the width direction A2 is connected to the upper end of the third plate member 121c. A separation roller shaft 113a is attached to the second plate member 121b and the third plate member 121c, and the holder 121 holds the separation roller shaft 113a and the separation roller 113.

[0034] The holder 121 is provided so as to be able to swing about a swing axis 121d that passes through the second plate member 121b and the third plate member 121c provided on the downstream side in the medium transport direction A1. One end of a pressing member 121e, the other end of which is supported by the upper housing 102, is attached to the upper surface of the first plate member 121a. The pressing member 121e is a spring member such as a compression coil spring or a rubber member. The holder 121 and the separation roller 113 are biased downward in the height direction A3, i.e., toward the feed roller 112 side, by the pressing member 121e.

[0035] Furthermore, the holder 121 may be provided detachably with respect to the upper housing 102. In this case, the user can easily replace the holder 121 when a failure or the like occurs in the holder 121, and the medium conveying device 100 can improve the convenience for the user.

[0036] The first driving source 122 is an example of a driving source, such as a motor. The first driving source 122 generates a driving force for rotating or stopping the separation roller 113 in a direction A5 opposite to the medium feeding direction, according to a control signal from a processing circuit described later. Note that the first driving source 122 may further rotate the first conveying roller 114, the second conveying roller 115, the third conveying roller 117, and / or the fourth conveying roller 118 in the medium conveying directions A6, A7, A8, and / or A9 by the driving force.

[0037] A first gear 123 is attached to the rotating shaft of the first driving source 122. The first gear 123 is engaged with a larger gear portion provided on an electromagnetic clutch 124. A smaller gear portion provided on the electromagnetic clutch 124 is engaged with a second gear 125 provided so as to be fixed to one end of a first shaft 126.

[0038] The electromagnetic clutch 124 is a clutch that can electromagnetically change the torque limit value in accordance with a control signal from a processing circuit described later. The electromagnetic clutch 124 is, for example, a micro-powder clutch, a hysteresis clutch, or the like. The electromagnetic clutch 124 transmits a driving force from the first driving source 122 to the separation roller 113 via the driving connection part 127, while controlling the load applied to the separation roller 113 via the driving connection part 127.

[0039] The first shaft 126 is an example of a second drive shaft. The first shaft 126 is provided outside the holder 121. The first shaft 126 receives a drive force from the first drive source 122 via the first gear 123, the electromagnetic clutch 124, and the second gear 125. The first shaft 126 transmits the drive force to the drive coupling portion 127 while rotating due to the drive force from the first drive source 122.

[0040] The drive connecting portion 127 is a universal joint such as a universal joint. The drive connecting portion 127 may be another universal joint such as a spherical joint, a constant velocity joint (Rzeppa joint), a Cardan joint, etc. The drive connecting portion 127 includes a first receiving member 127a, a second receiving member 127b, and a joint shaft member 127c. The first receiving member 127a is fixed to an end of the first shaft 126 opposite to the end where the second gear 125 is provided, and is connected to the first shaft 126. The second receiving member 127b is fixed to one end of the second shaft 128, and is connected to the second shaft 128. The joint shaft member 127c connects the first receiving member 127a and the second receiving member 127b so as to be able to tilt. As a result, the drive connecting portion 127 connects the first shaft 126 and the second shaft 128 to be able to tilt freely, and transmits the rotational drive force from the first shaft 126 to the second shaft 128. In other words, the drive connecting portion 127 is provided so as to be able to transmit the drive force from the first drive source 122 to the second shaft 128.

[0041] The second shaft 128 is an example of a drive shaft. The second shaft 128 is attached to the second plate member 121b of the holder 121, and the holder 121 holds the second shaft 128. A third gear 129 is fixedly provided to the end of the second shaft 128 opposite to the end where the second receiving member 127b is provided. A fourth gear 130 is engaged with the third gear 129, and a fifth gear 131 is engaged with the fourth gear 130. The fifth gear 131 is fixedly provided to the end of the separation roller shaft 113a on the drive connecting portion 127 side. In this way, the second shaft 128 is mechanically connected to the separation roller shaft 113a via the third gear 129, the fourth gear 130, and the fifth gear 131.

[0042] The torque limiter 132 is provided on the separation roller shaft 113a and controls the load applied to the separation roller 113. The limit value of the torque limiter 132 is set to a value such that the rotational force via the torque limiter 132 is cut off when there is one medium, and the rotational force via the torque limiter 132 is transmitted when there are multiple media. By providing the torque limiter 132 on the rotation shaft of the separation roller 113, there is no gear train between the torque limiter 132 and the separation roller 113, so that the separation force applied to the separation roller 113 is suppressed from fluctuating due to manufacturing errors of each part, etc. Therefore, the medium conveying device 100 can separate the medium with high accuracy regardless of the manufacturing errors of each part. Note that the torque limiter 132 does not necessarily have to be provided on the separation roller shaft 113a, and may be provided at any position between the first drive source 122 and the separation roller 113.

[0043] Also, either one of the torque limiter 132 and the electromagnetic clutch 124 may be omitted. In the case where the electromagnetic clutch 124 is omitted, gears that engage with each of the first gear 123 and the second gear 125 are disposed in place of the electromagnetic clutch 124.

[0044] The first gear 123, the electromagnetic clutch 124, the second gear 125, the first shaft 126, the drive connecting portion 127, the second shaft 128, the third gear 129, the fourth gear 130, the fifth gear 131, the torque limiter 132, and the separation roller shaft 113a function as a drive force transmission mechanism that transmits the drive force from the first drive source 122 to the separation roller 113. Note that as the drive force transmission mechanism for the separation roller 113, a pulley, a belt, or the like may be used instead of or in addition to the above configuration.

[0045] The feed roller 112 is provided to be rotatable about a feed roller shaft 112a. A sixth gear 133 is fixedly provided to one end of the feed roller shaft 112a. The sixth gear 133 is connected to a second driving source (described later) via a gear, a pulley, and / or a belt. The sixth gear 133 functions as a driving force transmission mechanism that transmits driving force from the second driving source to the feed roller 112.

[0046] Fig. 4 is a schematic diagram for explaining the positional relationship between the separation roller, the holder, the drive connector, etc. according to one embodiment. Fig. 4 is a schematic diagram showing the periphery of the separation roller 113, the holder 121, the drive connector 127, etc., as viewed from the side in a state in which the medium is not being transported.

[0047] As shown in FIG. 4, the specific position of the second shaft 128 is disposed at a position closer to the specific position of the oscillation shaft 121d of the holder 121 than the specific position of the separation roller shaft 113a, which is the rotation shaft of the separation roller 113. The specific position is, for example, a central position. The specific position may be any other position, such as the highest position, the lowest position, the most upstream position, or the most downstream position. That is, the distance D1 between the second shaft 128 and the oscillation shaft 121d of the holder 121 is smaller than the distance D2 between the separation roller shaft 113a, which is the rotation shaft of the separation roller 113, and the oscillation shaft 121d of the holder 121. It is preferable that the distance D1 between the second shaft 128 and the oscillation shaft 121d is further smaller than the distance between the second shaft 128 and the separation roller shaft 113a.

[0048] Moreover, in the medium conveying direction A1, the specific position of the second shaft 128 is disposed between the specific position of the separation roller shaft 113a and the specific position of the oscillation shaft 121d. That is, the second shaft 128 is disposed between the separation roller shaft 113a and the oscillation shaft 121d. Moreover, in the medium conveying direction A1, it is preferable that the specific position of the oscillation shaft 121d is disposed closer to the specific position of the second shaft 128 than the specific position of the separation roller shaft 113a. That is, in the medium conveying direction A1, it is preferable that the distance between the second shaft 128 and the oscillation shaft 121d is smaller than the distance between the second shaft 128 and the separation roller shaft 113a.

[0049] Furthermore, in the height direction A3, the specific position of the second shaft 128 is disposed above the specific position of the swing shaft 121d of the holder 121. That is, the distance D3 between the second shaft 128 and the lower guide 107a is greater than the distance D4 between the swing shaft 121d of the holder 121 and the lower guide 107a. Note that the distance D4 between the swing shaft 121d of the holder 121 and the lower guide 107a is set to 7 mm or more. This allows the medium conveying device 100 to properly convey a booklet such as a passport having a thickness of 7 mm.

[0050] Further, the specific position of the oscillation shaft 121d of the holder 121 is disposed above an imaginary plane N obtained by extending the nip surface between the separation roller 113 and the feed roller 112 in the medium transport direction A1, i.e., on the separation roller 113 side. In other words, the oscillation shaft 121d of the holder 121 is disposed on the separation roller 113 side of an imaginary plane N obtained by extending the nip surface between the separation roller 113 and the feed roller 112 in the medium transport direction A1.

[0051] Further, a distance D2 between a specific position of separation roller shaft 113a, which is the rotation axis of separation roller 113, and a specific position of oscillation axis 121d of holder 121 is smaller than a diameter D5 of separation roller 113. In other words, the distance D2 between separation roller shaft 113a, which is the rotation axis of separation roller 113, and oscillation axis 121d of holder 121 is smaller than a diameter D5 of separation roller 113.

[0052] Fig. 5 is a schematic diagram for explaining the operation of the separation roller, the holder, the drive connector, etc. according to one embodiment. Fig. 5 is a schematic diagram showing the periphery of the separation roller 113, the holder 121, the drive connector 127, etc. as viewed from the side in a state in which a thick medium M is being transported.

[0053] 5, when a thick medium M is transported and enters between the separation roller 113 and the feed roller 112, the separation roller 113 rises according to the thickness of the medium M. As a result, the upstream portion of the holder 121 in the medium transport direction A1 pushes up the pressing member 121e and swings about the swing shaft 121d arranged on the downstream side in the medium transport direction A1.

[0054] 6 and 7 are schematic diagrams of the separation roller 113, holder 121, drive connector 127, and the like, viewed from the upstream side in the medium transport direction A1. Fig. 6 shows the separation roller, holder, drive connector, and the like in a state where no medium is being transported, according to one embodiment. Fig. 7 shows the separation roller, holder, drive connector, and the like in a state where a thick medium M is being transported, according to one embodiment.

[0055] 4 and 6, in a state where a medium is not being transported, the separation roller 113 abuts against the feed roller 112, and the holder 121 is disposed at the initial position. As shown in Fig. 6, in a state where the holder 121 is disposed at the initial position, the joint shaft member 127c of the drive connecting portion 127 is disposed so as to extend substantially horizontally, that is, substantially parallel to the width direction A2.

[0056] 5 and 7, when a thick medium M is being transported between the separation roller 113 and the feed roller 112, the separation roller 113 rises according to the thickness of the medium M. As a result, the upstream portion of the holder 121 pushes up the pressing member 121e, swings about the swing shaft 121d, and is positioned at a raised position above the initial position. As shown in FIG. 7, when the holder 121 is positioned at the raised position, the joint shaft member 127c of the drive connecting portion 127 is tilted and positioned so that the second receiving member 127b side (the holder 121 side) is positioned higher than the first receiving member 127a side (the opposite side of the holder 121).

[0057] The following describes the forces applied to the separation roller 113. As shown in Fig. 4, the separation roller 113 is applied with a first force F1, a second force F2, and a third force F3.

[0058] The first force F1 is a force due to the rotational moment of the holder 121. When the medium is fed by the feed roller 112, the rotational force of the feed roller 112 in the medium feeding direction A4 is transmitted to the separation roller 113 via the medium, and the separation roller 113 is imparted with a rotational force in the medium feeding direction. As a result, a rotational moment in the same direction as the rotational force imparted to the separation roller 113 is imparted to the entire holder 121, and the first force F1 toward the feed roller 112 side is imparted to the separation roller 113. In other words, the first force F1 is a dynamic force due to the rotational moment applied to the swing shaft 121d of the holder 121 according to the torque applied to the separation roller 113, and is imparted so as to cause the separation roller 113 to bite into the feed roller 112 side.

[0059] The first force F1 changes depending on the positional relationship between the nip position between the feed roller 112 and the separation roller 113 and the pivot shaft 121d of the separation 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 applied to the separation roller 113. R is the radius of the separation roller 113. H is a first distance between the nip position of the feed roller 112 and the separation roller 113 in a direction perpendicular to the nip surface of the feed roller 112 and the separation roller 113 and the center position of the oscillation shaft 121d (see FIG. 4). A is a second distance between the nip position of the feed roller 112 and the separation roller 113 in a direction parallel to the nip surface of the feed roller 112 and the separation roller 113 and the center position of the oscillation shaft 121d (see FIG. 4).

[0060] The second force F2 is a force that tends to lift the separation roller 113 upward, which is generated by the gear transmission torque of the third gear 129, the fourth gear 130, and the fifth gear 131. The third force F3 is a pressing force by the pressing member 121e that presses the separation roller 113 toward the feed roller 112. The third force F3 is a static force that is determined according to the spring constant of the pressing member 121e, etc. A force of a magnitude obtained by subtracting the magnitude of the second force F2 from the sum of the magnitude of the first force F1 and the magnitude of the third force F3 acts on the separation roller 113 in a direction in which the separation roller 113 presses the feed roller 112.

[0061] In order for the feed roller 112 and the separation roller 113 to properly separate the media, the feed roller 112 and the separation roller 113 need to pinch the media with a specified force. If the force with which the feed roller 112 and the separation roller 113 pinch the media is too large, there is a possibility that double feeding of media will occur. Therefore, the force pressing the separation roller 113 towards the feed roller 112 and the force separating the separation roller 113 from the feed roller 112 need to be properly balanced.

[0062] As described above, the force pressing the separation roller 113 toward the feed roller 112 includes the first force F1 due to the rotational moment of the holder 121 and the third force F3 due to the pressing force from the pressing member 121e. The third force F3 is a static force due to the pressing force of the pressing member 121e and does not fluctuate when the medium is fed. On the other hand, the first force F1 is a dynamic force that occurs with the feeding of the medium. The first force F1 fluctuates slightly due to slight vibrations caused by unevenness formed on the surfaces (rubber) of the feed roller 112 and the separation roller 113, or the engagement timing of the torque limiter 132 or the members inside the electromagnetic clutch 124, etc.

[0063] When the first force F1 is large relative to the third force F3, the degree of fluctuation of the force applied to the medium during feeding increases. When the force applied to the medium increases, the force with which the feed roller 112 and the separation roller 113 pinch the medium becomes too large, and there is a possibility that double feeding of the medium occurs. Also, when the force applied to the medium decreases, the medium that is not the object of feeding advances between the feed roller 112 and the separation roller 113, and there is a possibility that double feeding of the medium occurs. Therefore, in order to stabilize the force applied to the medium and suppress the occurrence of double feeding of the medium, it is desirable to make the first force F1 small relative to the third force F3. However, among the first force F1, the torque limit value T and the radius R of the separation roller 113 should be adjusted according to the characteristics of the medium to be fed. Therefore, it is preferable to make the first force F1 small by bringing the swing shaft 121d of the holder 121 close to the nip surface of the feed roller 112 and the separation roller 113 in the height direction A3 to reduce the first distance H. It is also preferable to reduce the first force F1 by moving the pivot shaft 121d of the holder 121 away from the nip position of the feed roller 112 and the separation roller 113 in the medium transport direction A1 to increase the second distance A. In particular, it is preferable to set the first distance H to be equal to or less than the second distance A.

[0064] If the swing shaft 121d is provided with a driving force transmission member, such as a gear or a pulley, for transmitting the driving force from the first driving source 122 to the separation roller 113, there is a possibility that the driving force transmission member will be exposed to the medium conveying path when the first distance H is reduced. Also, if the swing shaft 121d is provided with a driving force transmission member, there is a possibility that the driving force transmission member will come into contact with a roller or an imaging device 116 provided downstream of the separation roller 113 when the second distance A is increased. In the medium conveying device 100, the second shaft 128, which is a driving shaft for transmitting the driving force from the first driving source 122 to the separation roller 113, is disposed at a position different from the swing shaft 121d. As a result, the medium conveying device 100 can reduce the first force F1, suppress the occurrence of double feeding of media, and improve the separation performance of the media, while avoiding the driving force transmission member from being exposed to the medium conveying path or coming into contact with other parts.

[0065] Furthermore, by arranging second shaft 128 at a position different from oscillation axis 121d, the degree of freedom in designing medium conveying device 100 is increased, and designers can flexibly design medium conveying device 100. Furthermore, by arranging second shaft 128 at a position different from oscillation axis 121d, holder 121 can be easily attached and detached to upper housing 102, and a user can easily replace holder 121 in the event of a breakdown or the like of holder 121. Therefore, medium conveying device 100 can improve user convenience.

[0066] Furthermore, medium conveying device 100 uses a universal joint that connects first shaft 126 provided outside holder 121 and second shaft 128 provided in holder 121 in a manner that allows the shaft to tilt freely, as drive connecting section 127 that transmits the drive force from first drive source 122 to separation roller 113. By using a universal joint, medium conveying device 100 can continue to transmit the drive force from first drive source 122 to separation roller 113 without interruption, even if holder 121 that holds separation roller 113 wobbles as separation roller 113 rises.

[0067] In particular, as described above, the distance D1 between the second shaft 128 and the swing shaft 121d of the holder 121 is smaller than the distance D2 between the separation roller shaft 113a and the swing shaft 121d of the holder 121. By arranging the second shaft 128 at a position closer to the swing shaft 121d of the holder 121 than the separation roller shaft 113a, the movement amount of the drive connector 127 becomes smaller relative to the movement amount of the separation roller 113. Therefore, the medium conveying device 100 can reduce the angular fluctuation of the drive connector 127 when a medium having a thickness is conveyed, and can increase the transmission efficiency of the driving force by the drive connector 127. Furthermore, by reducing the angular fluctuation of the drive connector 127, the medium conveying device 100 can reduce the length of the drive connector 127 (the length in the width direction A2), and can reduce the device size in the width direction A2. Furthermore, the medium conveying device 100 can increase the maximum amount of movement of the separation roller 113 within the range in which the drive connecting portion 127 can move, and can increase the maximum thickness of the medium that the device can convey.

[0068] Furthermore, as described above, the distance D3 between the second shaft 128 and the lower guide 107a is greater than the distance D4 between the swing shaft 121d of the holder 121 and the lower guide 107a. By arranging the second shaft 128 above the swing shaft 121d of the holder 121, it is possible to prevent members for transmitting the driving force from the first driving source 122 to the separation roller 113, such as the third gear 129, from being exposed to the media transport path. Therefore, the media transport device 100 can ensure a sufficient height of the media transport path, and can increase the maximum thickness of media that the device can transport.

[0069] As described above, the pivot shaft 121d of the holder 121 is disposed on the separation roller 113 side of the imaginary plane N that is an extension of the nip surface between the separation roller 113 and the feed roller 112 in the medium conveying direction A1. By disposing the pivot shaft 121d of the holder 121 on the separation roller 113 side, the medium conveying device 100 can ensure a sufficient height of the medium conveying path without bending the medium conveying path significantly. Therefore, the medium conveying device 100 can increase the maximum thickness of the medium that the device can support while suppressing an increase in the device size.

[0070] As described above, the distance D2 between the separation roller shaft 113a and the oscillation axis 121d of the holder 121 is smaller than the diameter D5 of the separation roller 113. By disposing the oscillation axis 121d of the holder 121 close to the separation roller shaft 113a, the medium conveying device 100 can reduce the size of the holder 121, thereby reducing the size and weight of the device.

[0071] FIG. 8 is a block diagram showing a schematic configuration of a medium conveying device according to an embodiment.

[0072] In addition to the above-mentioned components, the medium conveying device 100 further includes a second driving source 134, an interface device 135, a storage device 140, a processing circuit 150, and the like.

[0073] The second drive source 134 includes one or more motors, and rotates the feed roller 112, the first transport roller 114, the second transport roller 115, the third transport roller 117, and / or the fourth transport roller 118 in response to a control signal from the processing circuit 150 to transport the medium. Note that one of the first transport roller 114 and the second transport roller 115 may be a driven roller that rotates following the other roller. Also, one of the third transport roller 117 and the fourth transport roller 118 may be a driven roller that rotates following the other roller.

[0074] The interface device 135 has an interface circuit conforming to a serial bus such as a Universal Serial Bus (USB). The interface device 135 is electrically connected to an information processing device (such as a personal computer, a portable information terminal, etc.) to transmit and receive a scanned image and various information. Instead of the interface device 135, a communication unit having an antenna for transmitting and receiving a wireless signal and a wireless communication interface device for transmitting and receiving a signal through a wireless communication line according to a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network).

[0075] The storage device 140 includes a memory device such as a RAM (Random Access Memory) or a ROM (Read Only Memory), 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 140 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 140 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or the like. The computer programs may be distributed from a server or the like and installed in the storage device 140.

[0076] The processing circuit 150 operates based on a program previously stored in the storage device 140. The processing circuit 150 is, for example, a CPU (Central Processing Unit). As the processing circuit 150, a DSP (digital signal processor), an LSI (large scale integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or the like may be used.

[0077] The processing circuit 150 is connected to the operation device 105, the display device 106, the medium sensor 111, the imaging device 116, the first driving source 122, the electromagnetic clutch 124, the second driving source 134, the interface device 135, the storage device 140, etc., and controls each of these components. The processing circuit 150 performs drive control of the first driving source 122 and the second driving source 134, image capture control of the imaging device 116, etc., obtains an input image, and transmits it to the information processing device via the interface device 135.

[0078] FIG. 9 is a diagram showing a schematic configuration of a storage device and a processing circuit according to an embodiment.

[0079] 9, the storage device 140 stores a control program 141, an image acquisition program 142, etc. Each of these programs is a functional module implemented by software that runs on a processor. The processing circuit 150 reads each program stored in the storage device 140 and operates according to the read programs, thereby functioning as a control unit 151 and an image acquisition unit 152.

[0080] FIG. 10 is a flowchart showing an example of the operation of the medium reading process.

[0081] An example of the operation of the medium reading process of the medium conveying device according to one embodiment will be described below with reference to the flowchart shown in Fig. 10. Note that the flow of the operation described below is executed mainly by the processing circuit 150 in cooperation with each element of the medium conveying device 100 based on a program stored in advance in the storage device 140.

[0082] First, the control unit 151 waits until a user inputs an instruction to read a medium using the operation device 105 or an information processing device, and an operation signal instructing to read a medium is received from the operation device 105 or the interface device 135 (step S101). The operation signal may include job information specified by the user. The job information is a setting related to the image reading process. The job information includes settings such as the type of medium (general paper / thin paper / card / business card / photo, etc.), color settings of the input image (color / grayscale / black and white, etc.), resolution (200 dpi / 300 dpi / 600 dpi, etc.), or reading side (double-sided / single-sided).

[0083] Next, control unit 151 acquires a medium signal from medium sensor 111, and determines whether or not a medium is placed on mounting table 103 based on the acquired medium signal (step S102). If no medium is placed on mounting table 103, control unit 151 ends the series of steps.

[0084] On the other hand, when a medium is placed on the placement table 103, the control unit 151 sets the limit value of the torque by the electromagnetic clutch 124 (step S103). The control unit 151 identifies the type of medium to be conveyed, for example, from job information included in the operation signal. The medium conveying device 100 stores in advance in the storage device 140 a table showing the relationship between the type of medium and the limit value of the torque by the electromagnetic clutch 124. The control unit 151 refers to the table stored in the storage device 140, identifies the limit value corresponding to the identified type of medium, and sets it in the electromagnetic clutch 124. For example, the limit value of the torque by the electromagnetic clutch 124 is set to a value smaller than the limit value of the torque by the torque limiter 132, and the limit value of the torque applied to the separation roller 113 is specified by the electromagnetic clutch 124. However, for a specific medium, the limit value is set to a value larger than the limit value of the torque by the torque limiter 132, and the limit value of the torque applied to the separation roller 113 is specified by the torque limiter 132. By using the electromagnetic clutch 124, the medium conveying device 100 can flexibly change the limit value of the torque applied to the separation roller 113 according to the type of medium being conveyed, and appropriately separate the medium.

[0085] Next, the control unit 151 drives the first driving source 122 and the second driving source 134 to rotate the rollers and feed and transport the medium (step S104).

[0086] Next, the control unit 151 causes the imaging device 116 to capture an image of the medium, acquires an input image from the imaging device 116, and outputs the acquired input image by transmitting it to the information processing device via the interface device 135 (step S105).

[0087] Next, control unit 151 determines whether or not a medium remains on mounting table 103 based on the medium signal received from medium sensor 111 (step S106). If a medium remains on mounting table 103, control unit 151 returns the process to step S105, and repeats the processes of steps S105 to S106.

[0088] On the other hand, if there are no media remaining on the mounting table 103, the control unit 151 controls the first driving source 122 and the second driving source 134 to stop the rollers (step S107), and ends the series of steps.

[0089] As described above in detail, the medium conveying device 100 has the separation roller shaft 113a of the separation roller 113, which is provided so as to be swingable about the swing axis 121d, and the holder 121 which holds the second shaft 128 which transmits a driving force to the separation roller shaft 113a. The medium conveying device 100 arranges the second shaft 128 in the holder 121 so that the distance between the second shaft 128 and the swing axis 121d is smaller than the distance between the separation roller shaft 113a and the swing axis 121d. This allows the medium conveying device 100 to reduce the moving distance of the second shaft 128 when the holder 121 swings, and to reduce the moving range of the mechanism which transmits the driving force to the separation roller 113. Therefore, in the medium conveying device 100 in which the holder 121 which holds the separation roller 113 is provided so as to be swingable, it is possible to reduce the size of the device.

[0090] Furthermore, the medium conveying device 100 can reduce the size of the device, thereby saving the installation area of ​​the device. This allows the user to set up the medium conveying device 100 in a small space on a desk, and the medium conveying device 100 can improve the convenience for the user.

[0091] FIG. 11 is a diagram showing a schematic configuration of a processing circuit of a medium conveying device according to another embodiment.

[0092] The processing circuit 250 is used in place of the processing circuit 150 of the medium conveying device 100, and executes medium reading processing and the like in place of the processing circuit 150. The processing circuit 250 has a control circuit 251, an image acquisition circuit 252, and the like. Note that each of these components may be composed of an independent integrated circuit, microprocessor, firmware, and the like.

[0093] The control circuit 251 is an example of a control unit, and has the same functions as the control unit 151. The control circuit 251 receives an operation signal from the operation device 105 or the interface device 135, and a medium signal from the medium sensor 111. Based on each piece of information received, the control circuit 251 sets a limit value for the torque by the electromagnetic clutch 124, and controls the first drive source 122 and the second drive source 134.

[0094] The image acquisition circuit 252 is an example of an image acquisition section, and has the same function as the image acquisition section 152. The image acquisition circuit 252 acquires an input image from the imaging device 116, and outputs it to the interface device 135.

[0095] As described above in detail, even when the processing circuit 250 is used, it is possible to reduce the size of the medium conveying device 100 in which the holder 121 that holds the separation roller 113 is arranged to be swingable.

[0096] Although preferred embodiments have been described above, the embodiments are not limited to these. For example, the drive connecting portion may be a shaft whose extending direction (inclination) does not change, instead of a universal joint. In this case, the first shaft 126 and the second shaft 128 are fixed to both ends of the shaft that is the drive connecting portion, and the shaft that is the drive connecting portion, the first shaft 126, and the second shaft 128 are fixed so as to extend on the same straight line. When the separation roller 113 rises, the second shaft 128, the drive connecting portion, and the first shaft 126 move in accordance with the rise of the separation roller 113 and the tilt of the holder 121, and the second gear 125 fixed to the first shaft 126 moves away from the electromagnetic clutch 124. In other words, when the holder 121 is positioned in the initial position, the drive connection portion transmits the drive force from the first drive source 122 to the first shaft 126, but when the holder 121 is positioned in the raised position, the drive connection portion does not transmit the drive force from the first drive source 122 to the first shaft 126.

[0097] Alternatively, if the drive connection part is a shaft whose extending direction (inclination) does not change, the first drive source 122, the first gear 123, and the electromagnetic clutch 124 may also be arranged to move in conjunction with the rise of the separation roller 113 and the tilt of the holder 121.

[0098] Further, in addition to or instead of the holder 121, a holder may be provided that holds the feed roller 112, the first conveyor roller 114, the second conveyor roller 115, the third conveyor roller 117, and / or the fourth conveyor roller 118. Each holder has the same structure and function as the holder 121, and the oscillation shaft of each holder, the rotation shaft of each roller held by each holder, and the drive shaft mechanically connected to the rotation shaft have the same positional relationship as the corresponding parts of the holder 121.

[0099] Also, a separation pad may be used instead of the separation roller 113. Also, the medium conveying device 100 may have a so-called U-turn path, and may feed and convey the media placed on the placement table in order from the top, and discharge the media onto the discharge table. [Explanation of symbols]

[0100] 100 medium conveying device, 107a lower guide, 113 separation roller, 113a separation roller shaft, 121 holder, 121d swing shaft, 122 first drive source, 124 electromagnetic clutch, 126 first shaft, 127 drive connection portion, 128 second shaft, 132 torque limiter

Claims

1. A roller that is rotatably mounted around a rotation axis, A drive shaft mechanically connected to the aforementioned rotating shaft, A holder that holds the aforementioned rotating shaft and the aforementioned drive shaft, and is also provided to be pivotable around the pivot axis, Power source and A universal joint capable of transmitting the driving force from the drive source to the drive shaft, The rotating shaft is provided with a torque limiter, The distance between the drive shaft and the pivot shaft is smaller than the distance between the rotation shaft and the pivot shaft. A media transport device characterized by the following features.

2. It also has an information section that provides information about the media, The media transport device according to claim 1, wherein the distance between the drive shaft and the guide portion is greater than the distance between the oscillating shaft and the guide portion.

3. The universal joint includes a tiltable joint shaft, The media transport device according to claim 1 or 2, wherein the joint shaft is arranged horizontally when viewed from the media transport direction when no media is being transported.

4. The media transport device according to claim 3, wherein the universal joint connects the drive shaft and a second drive shaft provided outside the holder and rotated by the drive source so as to be tiltable.

5. The media conveying device according to claim 1 or 2, wherein the oscillating shaft is positioned on the roller side of a virtual plane that extends the nip surface formed by the roller in the media conveying direction.

6. The media conveying device according to claim 1 or 2, further comprising an electromagnetic clutch that controls the load applied to the roller via the universal joint.

7. The media conveying device according to claim 1 or 2, wherein the distance between the rotating shaft and the oscillating shaft is smaller than the diameter of the roller.

Images