Image reading device

Abstract

To realize stabilization of a conveyance posture of a medium 3, and improve quality of a read image.SOLUTION: An image reading apparatus 1 includes: a first reading part 51 having a reading surface 41 that reads a first surface 35 of a medium 3 conveyed in a conveyance direction F along a conveyance path 2; a second reading part 52 that is disposed downstream of the first reading part and reads a second surface 36; a first conveyance roller pair 4 that is disposed an upstream of the first reading unit 51 and conveys the medium; and a second conveyance roller pair 6 that is disposed between the first reading part 51 and the second reading part 52 and conveys the medium. A tangential direction 38 of a first nip position 37 where the first transport roller pair 4 nips the medium is directed to a position on the upstream side in a transport direction of the reading surface 41 of the first reading part 51, and a tangential direction 40 of a second nip position 39 where the second transport roller pair 6 nips the medium is directed to a position on the upstream side in the transport direction of the reading surface 41 of the second reading part 52.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an image reading device. [Background technology]

[0002] An example of this type of device is the image reading device described in Patent Document 1. Patent Document 1 describes the following. Two imaging units are arranged facing each other, and a pair of transport rollers that transport the medium to these imaging units has a reverse-warping structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-51338 Summary of the Invention [Problem to be solved by the invention]

[0004] In the image reading device described in Patent Document 1, the center of the first driven roller is positioned shifted toward the first imaging unit from the center of the first transport roller. Therefore, the leading edge of the paper is transported along the glass surface of the first imaging unit. However, because the paper is transported away from the glass surface of the second imaging unit, there is a problem in that the image quality on the opposite side of the paper is reduced. Furthermore, there is no description or suggestion of a configuration in which two imaging units are arranged offset from one another. [Means for solving the problem]

[0005] In order to solve the above problem, the image reading device of the present invention comprises a first reading unit having a reading surface that reads a first side of a medium transported in a transport direction on a transport path, a second reading unit arranged downstream of the first reading unit in the transport direction and having a reading surface that reads a second side of the medium that is the opposite side to the first side, a first transport roller pair arranged upstream of the first reading unit in the transport direction and transporting the medium toward the first reading unit, and a second transport roller pair arranged between the first reading unit and the second reading unit in the transport direction and transporting the medium toward the second reading unit, wherein the tangent direction of the first nip position where the first transport roller pair nip the medium is toward an upstream position in the transport direction of the reading surface of the first reading unit, and the tangent direction of the second nip position where the second transport roller pair nip the medium is toward an upstream position in the transport direction of the reading surface of the second reading unit. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic side cross-sectional view of an image reading device according to a first embodiment. [Figure 2] FIG. 2 is an enlarged side cross-sectional view of a main part of FIG. 1. [Figure 3] FIG. 2 is a schematic enlarged cross-sectional side view of a main part of FIG. 1. [Figure 4] FIG. 4 is a schematic enlarged cross-sectional side view of a main part of FIG. 3. [Figure 5] FIG. 10 is a schematic enlarged cross-sectional side view of a main part of an image reading device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present invention will now be briefly described. An image reading device according to a first aspect of the present invention comprises a first reading unit having a reading surface that reads a first side of a medium transported in a transport direction on a transport path; a second reading unit arranged downstream of the first reading unit in the transport direction and having a reading surface that reads a second side of the medium that is the opposite side to the first side; a first pair of transport rollers arranged upstream of the first reading unit in the transport direction and transporting the medium toward the first reading unit; and a second pair of transport rollers arranged between the first reading unit and the second reading unit in the transport direction and transporting the medium toward the second reading unit, wherein the tangent direction of the first nip position where the first pair of transport rollers nip the medium is toward an upstream position in the transport direction of the reading surface of the first reading unit, and the tangent direction of the second nip position where the second pair of transport rollers nip the medium is toward an upstream position in the transport direction of the reading surface of the second reading unit.

[0008] According to this aspect, the tangent direction of the first nip position where the first transport roller pair nips the medium is toward a position upstream of the reading surface in the transport direction, and the tangent direction of the second nip position where the second transport roller pair nips the medium is toward a position upstream of the reading surface in the transport direction. This allows the medium to be transported with a force acting in a direction that causes the first surface to contact the reading surface of the first reading unit, and also with a force acting in a direction that causes the second surface to contact the reading surface of the second reading unit. This stabilizes the transport orientation of the medium, improving the quality of the read image. Furthermore, it is possible to prevent transport problems, such as jamming of the medium.

[0009] An image reading device according to a second aspect of the present invention is an aspect dependent on the first aspect, and is characterized in that the first pair of transport rollers, when viewed from the side, has a first upstream roller arranged above the transport path and a second upstream roller arranged below opposite the first upstream roller, and the second pair of transport rollers, when viewed from the side, has a first downstream roller arranged above the transport path and a second downstream roller arranged below opposite the first downstream roller, and when viewed from the side, the first reading unit is arranged above the transport path and the second reading unit is arranged below, and the tangent direction of the first nip position is created by positioning the rotation axis of the second upstream roller shifted toward the first reading unit from the rotation axis of the first upstream roller, and the tangent direction of the second nip position is created by positioning the rotation axis of the first downstream roller shifted toward the second reading unit from the rotation axis of the second downstream roller.

[0010] According to this aspect, when the first reading unit is disposed above the transport path and the second reading unit is disposed below it in a side view, the tangent direction of the first nip position is created by displacing the rotation axis of the second upstream roller toward the first reading unit relative to the rotation axis of the first upstream roller.Furthermore, the tangent direction of the second nip position is created by displacing the rotation axis of the first downstream roller toward the second reading unit relative to the rotation axis of the second downstream roller.This simplifies the structure, stabilizes the transport posture of the medium, and improves the quality of the read image.

[0011] An image reading device according to a third aspect of the present invention is an aspect dependent on the first aspect, and is characterized in that the first pair of transport rollers, when viewed from the side, has a first upstream roller arranged above the transport path and a second upstream roller arranged below opposite the first upstream roller, and the second pair of transport rollers, when viewed from the side, has a first downstream roller arranged above the transport path and a second downstream roller arranged below opposite the first downstream roller, and when viewed from the side, the first reading unit is arranged below the transport path and the second reading unit is arranged above, the tangent direction of the first nip position is created by positioning the rotation axis of the first upstream roller shifted toward the first reading unit from the rotation axis of the second upstream roller, and the tangent direction of the second nip position is created by positioning the rotation axis of the second downstream roller shifted toward the second reading unit from the rotation axis of the first downstream roller.

[0012] According to this aspect, when the first reading unit is disposed below the transport path and the second reading unit is disposed above it in a side view, the tangent direction of the first nip position is created by displacing the rotation axis of the first upstream roller toward the first reading unit relative to the rotation axis of the second upstream roller.Furthermore, the tangent direction of the second nip position is created by displacing the rotation axis of the second downstream roller toward the second reading unit relative to the rotation axis of the first downstream roller.This simplifies the structure, stabilizes the transport posture of the medium, and improves the quality of the read image.

[0013] An image reading device according to a fourth aspect of the present invention is an aspect dependent on the second or third aspect, characterized in that an angle formed between a first virtual line connecting the rotation axis of the first upstream roller and the rotation axis of the second upstream roller and a second virtual line perpendicular to the reading surface is between 3 degrees and 12 degrees, and an angle formed between a third virtual line connecting the rotation axis of the first downstream roller and the rotation axis of the second downstream roller and a fourth virtual line perpendicular to the reading surface is between 3 degrees and 12 degrees.

[0014] According to this aspect, the angle formed by a first imaginary line connecting the rotation axis of the first upstream roller and the rotation axis of the second upstream roller and a second imaginary line perpendicular to the reading surface is 3 degrees or more and 12 degrees or less. Furthermore, the angle formed by a third imaginary line connecting the rotation axis of the first downstream roller and the rotation axis of the second downstream roller and a fourth imaginary line perpendicular to the reading surface is 3 degrees or more and 12 degrees or less. This makes it possible to transport thick media without reducing transportability.

[0015] An image reading device according to a fifth aspect of the present invention is an aspect dependent on the first aspect, and comprises a first contact member arranged opposite the reading surface of the first reading unit and in contact with the second surface of the medium, and a second contact member arranged opposite the reading surface of the second reading unit and in contact with the first surface of the medium, wherein the first pair of transport rollers transports the medium toward a position between the reading surface of the first reading unit and the first contact member, and the second pair of transport rollers transports the medium toward a position between the reading surface of the second reading unit and the second contact member. This aspect can also be subordinate to any one of the second to fourth aspects.

[0016] According to this aspect, the medium conveying device includes a first contact member disposed opposite the reading surface of the first reading unit and in contact with the second side of the medium, and a second contact member disposed opposite the reading surface of the second reading unit and in contact with the first side of the medium. The first transport roller pair transports the medium toward the gap between the reading surface and the first contact member, and the second transport roller pair transports the medium toward the gap between the reading surface and the second contact member. This brings the first contact member into contact with the second side of the medium, and the second contact member into contact with the first side of the medium, further stabilizing the transport posture of the medium and further improving the quality of the read image. Furthermore, if the medium has wrinkles, the wrinkles can be smoothed out by the first contact member and the second contact member.

[0017] An image reading device according to a sixth aspect of the present invention is an aspect dependent on the fifth aspect, and is characterized in that it has a first rotating member that faces the reading surface of the first reading unit, is arranged downstream of the first contact member in the conveying direction, has a background member and is rotatable around an axis, and a second rotating member that faces the reading surface of the second reading unit, is arranged downstream of the second contact member in the conveying direction, has a background member and is rotatable around an axis.

[0018] According to this aspect, a first rotating member having a background member and rotatable about an axis is disposed downstream of the first contact member in the transport direction, facing the reading surface of the first reading unit. Furthermore, a second rotating member having a background member and rotatable about an axis is disposed downstream of the second contact member in the transport direction, facing the reading surface of the second reading unit. This not only stabilizes the transport orientation of the medium, but also ensures image reading quality even for relatively thin, light-transmitting media, thanks to the presence of the background member.

[0019] [Embodiment] Hereinafter, an embodiment of an image reading apparatus according to the present invention will be specifically described with reference to FIGS. In the following explanation, the three mutually orthogonal axes are referred to as the X-axis, Y-axis, and Z-axis, as shown in each figure. The directions indicated by the arrows on the three axes (X, Y, Z) are the + directions of each axis, and the opposite directions are the - directions. The Z-axis direction corresponds to the vertical direction, i.e., the direction in which gravity acts, the +Z direction indicates a vertically upward direction, and the -Z direction indicates a vertically downward direction. The X-axis and Y-axis directions correspond to horizontal directions. The +Y direction indicates the front direction of the image reading device, and the -Y direction indicates the rear direction of the device. The +X direction indicates the right direction of the device, and the -X direction indicates the left direction of the device.

[0020] [Embodiment 1] <Explanation of the overall structure of the image reading device> First, the overall structure of the image reading device 1 of the first embodiment will be described with reference to FIGS. The image reading device 1 of this embodiment is a scanner capable of reading an image on a medium. Here, the image refers to something visually recorded on the medium, such as characters, figures, tables, pictures, photographs, etc. The medium is not limited to sheets, but also includes cards, booklets, etc. The image reading device 1 is not limited to a scanner, but may also be a copy machine, a facsimile machine, etc. 1, the image reading device 1 includes two reading units 5, a first reading unit 51 and a second reading unit 52, that read an image on a medium 3. The first reading unit 51 and the second reading unit 52 are arranged apart in a transport direction F. The medium 3 is transported in the transport direction F along a transport path 2, and the image reading device 1 includes a first transport roller pair 4 provided upstream of the first reading unit 51, a second transport roller pair 6 provided upstream of a second reading unit 52 located downstream of the first reading unit 51, and a third transport roller pair 8 provided downstream of the second reading unit 52. A roller pair consisting of a feed roller 10 and a separation roller 7 is arranged upstream of the first transport roller pair 4 in the transport direction F. The feed roller 10 is a drive roller that rotates using the power of a first drive source 15, and transports the medium 3 in the transport direction F. The separation roller 7 is a drive roller that rotates using the power of a drive source (not shown), and is a roller that separates multiple sheets of medium 3 into a single sheet.

[0021] Here, the separation roller 7 is rotated by the power of the drive source in a direction that sends the medium 3 upstream (+Y direction) in the transport direction F. The separation roller 7 is equipped with a torque limiter (not shown), and when a torque exceeding a set value is applied to this torque limiter, the separation roller 7 is driven to rotate in a direction that sends the medium 3 downstream (-Y direction) in the transport direction F. A pick roller 12 is disposed upstream of the separation roller 7. The pick roller 12 is a drive roller that rotates by the same power of the first drive source 15 as the feed roller 10, and sends the medium 3 in the conveying direction F. The first conveying roller pair 4, the second conveying roller pair 6, and the third conveying roller pair 8 that form the conveying section 17 that conveys the medium 3 in the conveying direction F also include drive rollers that rotate by the power of the first drive source 15.

[0022] 1, in this embodiment, a curved reversing path 18 is provided downstream of the straight path 68 from the feed roller 10 to the third conveying roller pair 8, i.e., downstream of the third conveying roller pair 8. On the curved reversing path 18, a fourth conveying roller pair 20, a fifth conveying roller pair 22, and a discharge roller pair 24, which form a conveying section 17, are arranged in this order along the conveying direction F. The discharge receiver 16 that receives the medium 3 discharged from the curved reversing path 18 is disposed above the straight path 68, thereby achieving a compact design.

[0023] 1, reference numeral 71 denotes a control unit. The control unit 71 controls the driving of the first driving source 15 and the driving of the second driving source 27 (described later) in accordance with the transport of the medium 3. The first driving source 15 and the second driving source 27 are constituted by motors. The control unit 71 includes a CPU, a flash ROM, and a RAM. The CPU performs various arithmetic processing in accordance with programs stored in the flash ROM and controls the overall operation of the image reading device 1. The flash ROM, which is an example of a storage means, is a non-volatile memory that can be read and written. The RAM, which is also an example of a storage means, temporarily stores various pieces of information.

[0024] 1, reference numeral 14 denotes a medium placement unit on which a medium 3 to be read is set. The medium 3 on the medium placement unit 14 is transported along the transport path 2 and finally discharged to a discharge receiving unit 16. The medium loading unit 14 is configured to move up and down. When the media 3 set on the medium loading unit 14 are to be sent in the transport direction F, first, power is transmitted from a drive source (not shown) to the medium loading unit 14, which moves it upward (in the +Z direction), and the topmost set medium 3 stops in contact with the pick roller 12. In this state, the pick roller 12 rotates to send the medium 3 in the transport direction F, and the leading edge of the medium 3 reaches the nip position of the roller pair consisting of the feed roller 10 and the separation roller 7.

[0025] In the case of a multiple-feed state in which multiple sheets of medium 3 are fed, the sheets are separated into one sheet by separation roller 7, and that sheet is transported in transport direction F by first transport roller pair 4, and the image on first side 35 of medium 3 is read by first reading unit 51. Furthermore, medium 3 that has been read by first reading unit 51 is transported by second transport roller pair 6, and the image on second side 36 of medium 3, which is opposite to first side 35, is read by second reading unit 52. The medium 3 that has been read by the second reading unit 52 is transported by the third transport roller pair 8 and discharged to the discharge receiving unit 16 by the discharge roller pair 24.

[0026] 1 and 2, in this embodiment, the first reading unit 51 and the second reading unit 52 that read an image on a medium 3 transported in the transport direction F include a first light-transmitting member 431 and a second light-transmitting member 432 that are light-transmitting members 43 arranged between the first reading unit 51 and the transport path 52 and the second reading unit 52. Reference numeral 41 denotes the reading surface of the reading unit 51. 2, reference numeral 42 denotes the reading position of the second reading unit 52, and reference numeral 44 denotes the inclined surface. The inclined surface 44 is provided at the upstream end of the light-transmitting member 43 on the reading surface 41 side, and when the leading edge of the transported medium 3 comes into contact with the inclined surface 44, it guides the medium 3 to move in a direction along the transport path 2. The reading unit 5 has, for example, a CIS (Contact Image Sensor) type sensor or a CCD (Charge Coupled Device) type sensor that extends along the X-axis.

[0027] <Rotating parts> As shown in FIGS. 1 and 2, a first rotating member 31 and a second rotating member 32 as the rotating member 30 are arranged on the opposite side of the first reading unit 51 and the second reading unit 52 of the first light-transmitting member 431 and the second light-transmitting member 432. The first rotating member 31 and the second rotating member 32 are arranged opposite the first reading unit 51 and the second reading unit 52, and are rotating members that can rotate around an axis 11. Reference numeral 21 indicates the direction of rotation. The first rotating member 31 and the second rotating member 32 are substantially cylindrical, and are formed to a length that can cover the reading range (X-axis direction) of the first reading unit 51 and the second reading unit 52. As shown in FIG. 2, in this embodiment, the first rotating member 31 and the second rotating member 32 each include a background member 9 and a second cleaning unit 63. The second cleaning unit 63 is attached to the rotating member 30 with its tip protruding from the outer circumferential surface 13 of the rotating member 30. The second cleaning unit 63 wipes, i.e., cleans, the reading surface 41 as the rotating member 30 rotates in the rotation direction 21, i.e., around the axis 11. The background member 9 includes two members, a first background member 91 and a second background member 92, arranged as shown in FIG. 2. The background member 9 further includes a first cleaning unit 65 that can clean the first background member 91 and the second background member 92. In this embodiment, the first background member 91 creates a white background. The second background member 92 creates a black background. However, the colors are not limited to these. Any combination of colors with different contrasts will do. The first cleaning unit 65 cleans the first background member 91 and the second background member 92. The first cleaning unit 65 is a brush whose base end is fixed to a frame 19, which is a structural member of the upper unit 56 (FIG. 1) described below. Note that FIG. 2 is an enlarged view of the second reading unit 52, and therefore the first rotating member 31 is not visible.

[0028] Furthermore, the first rotating member 31 and the second rotating member 32 rotate around the axis 11 by the power of a second driving source 27, which is a common driving source. The rotational operations of the first rotating member 31 and the second rotating member 32 are controlled by a control unit 71. The second driving source 27 transmits power to the first rotating member 31 and the second rotating member 32 via a power transmission mechanism (not shown), causing them to rotate. The first rotating member 31 and the second rotating member 32 may be configured to rotate by the power of individual motors, rather than by the common second drive source 27.

[0029] The first reading unit 51, the first light-transmitting member 431, and the second rotating member 32 are disposed above the conveying path 2. The second reading unit 52, the second light-transmitting member 432, and the first rotating member 31 are disposed below the conveying path 2. 1, in this embodiment, the image reading device 1 is made up of a lower unit 55 and an upper unit 56. The upper unit 56 is configured to be able to rotate up and down relative to the lower unit 55 and be opened and closed by an opening and closing mechanism (not shown). The lower unit 55 has a second reading unit 52, a second light-transmitting member 432, and a first rotating member 31. The upper unit 56 has a first reading unit 51, a first light-transmitting member 431, and a second rotating member 32. When the upper unit 56 is closed relative to the lower unit 55, as shown in FIG. 1, the second light-transmitting member 432 and the second rotating member 32 face each other, and the first light-transmitting member 431 and the first rotating member 31 face each other. Although not shown, when the upper unit 56 is opened relative to the lower unit 55, the second light-transmitting member 432 and the second rotating member 32 do not face each other, and the first light-transmitting member 431 and the first rotating member 31 do not face each other. In other words, the opposing surfaces of the lower unit 55 and the upper unit 56 are exposed, allowing access by the user.

[0030] 1 to 3, this embodiment includes a first contact member 61 and a second contact member 62 that face the first light-transmitting member 431 and the second light-transmitting member 432, are disposed upstream of the first rotating member 31 and the second rotating member 32, and serve as contact members that assist in transporting the medium 3. Here, the first contact member 61 and the second contact member 62 are configured as drive rollers called platen rollers 26 that rotate when power from the first drive source 15 is transmitted thereto.

[0031] Next, one of the main parts of the image reading device 1 of the first embodiment will be described below with reference to FIGS. 3, the image reading device 1 of this embodiment includes a first reading unit 51 having a reading surface 41 that reads a first side 35 of a medium 3 transported on a transport path 2 in a transport direction F. The image reading device 1 also includes a second reading unit 52 that is disposed downstream of the first reading unit 51 in the transport direction F and has a reading surface 41 that reads a second side 36 of the medium 3, which is the opposite side to the first side 35. The image reading device 1 also includes a first transport roller pair 4 that is disposed upstream of the first reading unit 51 in the transport direction F and transports the medium 3 toward the first reading unit 51. The image reading device 1 also includes a second transport roller pair 6 that is disposed between the first reading unit 51 and the second reading unit 52 in the transport direction and transports the medium 3 toward the second reading unit 52.

[0032] A tangent direction 38 of a first nip position 37 where the first transport roller pair 4 nip the medium 3 is configured to face an upstream position in the transport direction F of the reading surface 41 of the first reading unit 51. Furthermore, a tangent direction 40 of a second nip position 39 where the second transport roller pair 6 nip the medium 3 is configured to face an upstream position in the transport direction F of a reading surface 41 of the second reading unit 52.

[0033] As shown in FIGS. 1 and 3, in this embodiment, the first reading unit 51 is disposed above the conveying path 2 and the second reading unit 52 is disposed below it in a side view. Furthermore, in this embodiment, the first conveying roller pair 4 has, in a side view, a first upstream roller 45 arranged above the conveying path 2, and a second upstream roller 46 arranged below and opposite the first upstream roller 45. Furthermore, the second conveying roller pair 6 has, in a side view, a first downstream roller 47 arranged above the conveying path 2, and a second downstream roller 48 arranged below and opposite the first downstream roller 47.

[0034] As shown in Figure 3, the tangential direction 38 of the first nip position 37 is created by positioning the center position of the rotation shaft 57 of the second upstream roller 46 so that it is shifted toward the first reading unit 51 (-Y side) from the center position of the rotation shaft 58 of the first upstream roller 45. Furthermore, the tangential direction 40 of the second nip position 39 is created by positioning the center position of the rotation axis 59 of the first downstream roller 47 shifted toward the second reading unit 52 (-Y side) from the center position of the rotation axis 60 of the second downstream roller 48.

[0035] As shown in Figure 3, in this embodiment, if the angle formed by a first virtual line L1 connecting the center position of the rotation shaft 58 of the first upstream roller 45 and the center position of the rotation shaft 57 of the second upstream roller 46 and a second virtual line L2 perpendicular to the reading surface 41 of the first reading unit 51 is θ1, the angle θ1 is set in the range of 3 degrees or more and 12 degrees or less, taking into account the thickness, i.e., rigidity, of the medium 3. Furthermore, if the angle formed by a third virtual line L3 connecting the center position of the rotation axis 59 of the first downstream roller 47 and the center position of the rotation axis of the second downstream roller 48 and a fourth virtual line L4 perpendicular to the reading surface 41 of the second reading unit 52 is θ2, the angle θ2 is set in the range of 3 degrees or more and 12 degrees or less, taking into account the thickness, i.e., rigidity, of the medium 3.

[0036] 4 is an enlarged view of the first reading unit 51 and the first transport roller pair 4 to exaggerate the misalignment. As shown in FIG. 4, the angle between the tangential direction 38 and the plane 34 parallel to the reading surface 41, i.e., the angle of the tangential direction 38 at the nip position 37, is also θ1. Although not shown, the angle formed by the tangential direction 40 and the plane 34 parallel to the reading surface 41, that is, the angle of the tangential direction 40 at the nip position 39, is also θ2.

[0037] 1 to 4, this embodiment has a first contact member 61 that is disposed opposite the reading surface 41 of the first reading unit 51 and that contacts the second surface 36 of the medium 3. It also has a second contact member 62 that is disposed opposite the reading surface 41 of the second reading unit 52 and that contacts the first surface 35 of the medium 3. The first transport roller pair 4 is configured to transport the medium 3 toward a gap between the reading surface 41 of the first reading unit 51 and the first contact member 61. Furthermore, the second transport roller pair 6 is configured to transport the medium 3 toward a gap between the reading surface 41 of the second reading unit 52 and the second contact member 62. The first contact member 61 and the second contact member 62 can be replaced with a means other than the platen roller 26, such as a pressure plate, wind pressure, or electrostatic attraction.

[0038] 1 to 4, although this explanation is repeated, this embodiment includes a first rotating member 31 that faces the reading surface 41 of the first reading unit 51 and is arranged downstream of the first contact member 61 in the conveying direction F. The first rotating member 31 has a background member 9 and is configured to be rotatable around an axis 11. Furthermore, the second reading unit 52 includes a second rotating member 32 that faces the reading surface 41 of the second reading unit 52 and is disposed downstream of the second contact member 62 in the conveying direction F. The second rotating member 32 has a background member 9 and is configured to be rotatable around an axis 11. As described above, the background member 9 is made up of two members, the white first background member 91 and the black second background member 92, but is not limited to a set of white and black.

[0039] <Explanation of Effects of Embodiment 1> (1) In this embodiment, the tangent direction 38 of the first nip position 37 where the first transport roller pair 4 nip the medium 3 is directed toward an upstream position in the transport direction F of the reading surface 41 of the first reading unit 51, and the tangent direction 40 of the second nip position 39 where the second transport roller pair 6 nip the medium 3 is directed toward an upstream position in the transport direction F of the reading surface 41 of the second reading unit 52. As a result, the medium 3 is transported with a force acting in a direction that causes the first surface 35 to contact the reading surface 41 of the first reading unit 51, and further with a force acting in a direction that causes the second surface 36 to contact the reading surface 41 of the second reading unit 52. This stabilizes the transport orientation of the medium 3 and improves the quality of the read image. Furthermore, it is possible to prevent transport problems such as jamming of the medium 3.

[0040] (2) In addition, in this embodiment, as shown in FIGS. 1 and 3, when the first reading unit 51 is disposed above the conveyance path 2 and the second reading unit 52 is disposed below it in a side view, the tangent direction 38 of the first nip position 37 is created by displacing the rotation axis 57 of the second upstream roller 46 toward the first reading unit 51 relative to the rotation axis 58 of the first upstream roller 45. Furthermore, the tangent direction 40 of the second nip position 39 is created by displacing the rotation axis 59 of the first downstream roller 47 toward the second reading unit 52 relative to the rotation axis 60 of the second downstream roller 48. This simplifies the structure, stabilizes the conveyance posture of the medium 3, and improves the quality of the read image.

[0041] (3) In this embodiment, the angle θ1 between a first imaginary line L1 connecting the rotation axis 58 of the first upstream roller 45 and the rotation axis 57 of the second upstream roller 46 and a second imaginary line L2 perpendicular to the reading surface 41 is 3 degrees or greater and 12 degrees or less. Furthermore, the angle θ2 between a third imaginary line L3 connecting the rotation axis 59 of the first downstream roller 47 and the rotation axis 60 of the second downstream roller 48 and a fourth imaginary line L4 perpendicular to the reading surface 41 is 3 degrees or greater and 12 degrees or less. This allows the medium 3 to be transported without a decrease in transportability, even if it is thick.

[0042] (4) In addition, this embodiment includes a first contact member 61 disposed opposite the reading surface 41 of the first reading unit 51 and in contact with the second surface 36 of the medium 3, and a second contact member 62 disposed opposite the reading surface 41 of the second reading unit 52 and in contact with the first surface 35 of the medium 3. The first transport roller pair 4 transports the medium 3 toward the gap between the reading surface 41 and the first contact member 61, and the second transport roller pair 6 transports the medium 3 toward the gap between the reading surface 41 and the second contact member 62. This allows the first contact member 61 to contact the second surface 36 of the medium 3 and the second contact member 62 to contact the first surface 35 of the medium 3, further stabilizing the transport posture of the medium 3 and further improving the quality of the read image. Furthermore, if wrinkles occur in the medium 3, the first contact member 61 and the second contact member 62 can smooth out the wrinkles.

[0043] (5) In addition, in this embodiment, the first rotating member 31, which has the background member 9 and is rotatable around the axis 11, is disposed downstream of the first contact member 61 in the transport direction F, at a position facing the reading surface 41 of the first reading unit 51. Furthermore, the second rotating member 32, which has the background member 9 and is rotatable around the axis 11, is disposed downstream of the second contact member 62 in the transport direction F, at a position facing the reading surface 41 of the second reading unit 52. This not only stabilizes the transport orientation of the medium 3, but also ensures image reading quality even for relatively thin, light-transmitting media 3, thanks to the presence of the background member 9.

[0044] [Embodiment 2] Next, an image reading device 1 according to a second embodiment will be described with reference to Fig. 5. The same parts as those in the first embodiment will be given the same reference numerals, and a description of the configurations and corresponding effects will be omitted. 5, in this embodiment, in a side view, the first reading unit 51 is disposed below the conveying path 2, and the second reading unit 52 is disposed above it. That is, the first reading unit 51 and the second reading unit 52 are disposed upside down in the opposite direction to that in the first embodiment. Furthermore, in this embodiment, as with embodiment 1, the first conveying roller pair 4 has, in side view, a first upstream roller 45 arranged above the conveying path 2, and a second upstream roller 46 arranged below and opposite the first upstream roller. Furthermore, the second conveying roller pair 6 has, in a side view, a first downstream roller 47 arranged above the conveying path 2, and a second downstream roller 48 arranged below and opposite the first downstream roller 47.

[0045] As shown in Figure 5, the tangential direction 38 of the first nip position 37 is created by positioning the center position of the rotation shaft 58 of the first upstream roller 45 so that it is shifted toward the first reading unit 51 (-Y side) from the center position of the rotation shaft 57 of the second upstream roller 46. Furthermore, the tangential direction 40 of the second nip position 39 is created by positioning the center position of the rotation axis 60 of the second downstream roller 48 shifted toward the second reading unit 52 (-Y side) from the center position of the rotation axis 59 of the first downstream roller 47.

[0046] 5, in a side view, when the first reading unit 51 is disposed below the conveyance path 2 and the second reading unit 52 is disposed above it, the tangent direction 38 of the first nip position 37 is created by displacing the rotation axis 58 of the first upstream roller 45 closer to the first reading unit 51 than the rotation axis 57 of the second upstream roller 46. Furthermore, the tangent direction 40 of the second nip position 39 is created by displacing the rotation axis 60 of the second downstream roller 48 closer to the second reading unit 52 than the rotation axis 59 of the first downstream roller 47. This simplifies the structure, stabilizes the conveyance posture of the medium 3, and improves the quality of the read image.

[0047] Other Embodiments The image reading device 1 according to the present invention is based on the configuration of the embodiment described above, but it is of course possible to modify or omit some of the configuration within the scope of the gist of the present invention. In the above description, the first reading unit 51 and the second reading unit 52 are arranged apart from each other in the horizontal Y-axis direction, but this arrangement is not limited to this. For example, the first reading unit 51 and the second reading unit 52 may be arranged apart from each other in the vertical Z-axis direction, i.e., offset. [Explanation of symbols]

[0048] 1...image reading device, 2...conveying path, 3...medium, 4...first conveying roller pair, 5...reading unit, 6...second conveying roller pair, 7...separation roller, 8...Third conveying roller pair, 9...Background member, 10...Feed roller, 11...Shaft, 12... pick roller, 13... outer peripheral surface, 14... medium placement portion, 15... first driving source, 16... discharge receiving portion, 17... conveying portion, 18... curved inversion path, 19... frame, 20...Fourth conveying roller pair, 21...Rotation direction, 22...Fifth conveying roller pair, 24... Discharge roller pair, 26... Platen roller, 27... Second drive source, 30...rotating member, 31...first rotating member, 32...second rotating member, 34...surface parallel to the reading surface, 35...first surface, 36...second surface, 37...first nip position, 38...Tangential direction, 39...Second nip position, 40...Tangential direction, 41...Reading surface, 42...reading position, 43...light-transmitting member, 44...inclined surface, 45...first upstream roller, 46...second upstream roller, 47...first downstream roller, 48...second downstream roller, 51...first reading unit, 52...second reading unit, 55...lower unit, 56...upper unit, 57...rotating shaft, 58...rotating shaft, 59...rotating shaft, 60...rotating shaft, 61...first contact member, 62...second contact member, 63... second cleaning unit, 65... first cleaning unit, 68... straight path, 71... control unit, 91...first background member, 92...second background member, 431...first light-transmitting member, 432...second light-transmitting member, F...conveying direction, L1...first virtual line, L2...second virtual line, L3...third imaginary line, L4...fourth imaginary line, θ1...angle, θ2...angle

Claims

1. a first reading unit having a reading surface that reads a first surface of a medium transported in a transport direction on a transport path; a second reading unit disposed downstream of the first reading unit in the transport direction and having a reading surface that reads a second surface of the medium opposite to the first surface; a first transport roller pair disposed upstream of the first reading unit in the transport direction and configured to transport the medium toward the first reading unit; a second transport roller pair that is disposed between the first reading unit and the second reading unit in the transport direction and transports the medium toward the second reading unit; a tangent direction of a first nip position where the first transport roller pair nips the medium is directed toward an upstream position in the transport direction of a reading surface of the first reading unit; a tangent direction of a second nip position where the second transport roller pair nip the medium is directed toward an upstream position in the transport direction of the reading surface of the second reading unit; An image reading device characterized by:

2. 2. The image reading device according to claim 1, the first transport roller pair includes, in a side view, a first upstream roller disposed above the transport path and a second upstream roller disposed below and facing the first upstream roller; the second transport roller pair includes, in a side view, a first downstream roller disposed above the transport path and a second downstream roller disposed below and facing the first downstream roller; When viewed from the side, the first reading unit is disposed above the conveying path, and the second reading unit is disposed below the conveying path; a tangential direction of the first nip position is formed by disposing a rotation axis of the second upstream roller shifted toward the first reading unit with respect to a rotation axis of the first upstream roller, a tangential direction of the second nip position is formed by disposing the rotation axis of the first downstream roller to be shifted toward the second reading unit with respect to the rotation axis of the second downstream roller; An image reading device characterized by:

3. 2. The image reading device according to claim 1, the first transport roller pair includes, in a side view, a first upstream roller disposed above the transport path and a second upstream roller disposed below and facing the first upstream roller; the second transport roller pair includes, in a side view, a first downstream roller disposed above the transport path and a second downstream roller disposed below and facing the first downstream roller; When viewed from the side, the first reading unit is disposed below the conveying path, and the second reading unit is disposed above the conveying path; a tangential direction of the first nip position is formed by disposing a rotation axis of the first upstream roller to be shifted toward the first reading unit with respect to a rotation axis of the second upstream roller, a tangential direction of the second nip position is formed by disposing the rotation axis of the second downstream roller to be shifted toward the second reading unit side relative to the rotation axis of the first downstream roller; An image reading device characterized by:

4. 4. The image reading device according to claim 2 or 3, an angle formed by a first virtual line connecting the rotation axis of the first upstream roller and the rotation axis of the second upstream roller (a first nip position of the first conveyance roller pair) and a second virtual line perpendicular to a reading surface of the first reading unit is equal to or greater than 3 degrees and equal to or less than 12 degrees; an angle formed by a third virtual line connecting the rotation axis of the first downstream roller and the rotation axis of the second downstream roller (a second nip position of the second conveying roller pair) and a fourth virtual line perpendicular to the reading surface of the second reading unit is equal to or greater than 3 degrees and equal to or less than 12 degrees; An image reading device characterized by:

5. 2. The image reading device according to claim 1, a first contact member disposed opposite the reading surface of the first reading unit and in contact with the second surface of the medium; a second contact member that is disposed opposite the reading surface of the second reading unit and that contacts the first surface of the medium; the first transport roller pair transports the medium toward a gap between a reading surface of the first reading unit and the first contact member; the second transport roller pair transports the medium toward a gap between the reading surface of the second reading unit and the second contact member; An image reading device characterized by:

6. 6. The image reading device according to claim 5, a first rotating member that faces the reading surface of the first reading unit, is disposed downstream of the first contact member in the conveying direction, has a background member, and is rotatable about an axis; a second rotating member that faces the reading surface of the second reading unit, is disposed downstream of the second contact member in the conveying direction, has a background member, and is rotatable around an axis; An image reading device characterized by:

Images