Medium conveying device and image reading device

Abstract

To solve the problem in which in a prior art, there is need of improvement in terms of reducing the size of a device by considering the configuration and arrangement of an ultrasonic sensor.SOLUTION: A medium conveying device comprises: a first roller pair; a second roller pair arranged downstream of the first roller pair; and an ultrasonic detection unit arranged between the first roller pair and the second roller pair. The ultrasonic detection unit has a transmission sensor chip, a reception sensor chip, a transmission substrate on which the transmission sensor chip is provided, and a reception substrate on which the reception sensor chip is provided. A first axis is inclined with respect to a surface of a medium that passes through between the transmission sensor chip and the reception sensor chip. At least a part of the transmission sensor chip and at least a part of the reception sensor chip are within a range of the second roller pair in a normal direction with respect to a surface of the medium at a nip position of the second roller pair.SELECTED DRAWING: Figure 24

Description

[Technical field]

[0001] The present invention relates to a medium transport device that transports a medium, and an image reading device including the medium transport device. [Background technology]

[0002] Conventionally, a technique for detecting double-feeding of media using an ultrasonic sensor has been used, as shown in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-25242 A Summary of the Invention [Problem to be solved by the invention]

[0004] The use of ultrasonic sensors tends to lead to an increase in the size of the device. In the prior art, there was room for improvement in terms of miniaturizing the device by improving the configuration and arrangement of the ultrasonic sensor. [Means for solving the problem]

[0005] In order to solve the above problem, a medium transport device of the present invention is a medium transport device including a first roller pair that transports a medium in a transport direction, a second roller pair arranged downstream of the first roller pair in the transport direction, and an ultrasonic detection unit arranged between the first roller pair and the second roller pair in the transport direction, the ultrasonic detection unit including a transmitting sensor chip that emits ultrasonic waves along a first axis toward a first surface of the medium being transported, a receiving sensor chip that is arranged on the first axis at a position where the medium is sandwiched between the transmitting sensor chip and the receiving sensor chip and receives ultrasonic waves, and a transmitting board on which the transmitting sensor chip is provided, the transmitting sensor chip being disposed on a board surface, the first axis is inclined with respect to the surface of the medium passing between the transmitting sensor chip and the receiving sensor chip, the thickness of the transmitting sensor chip is thinner than the thickness of the transmitting substrate, the thickness of the receiving sensor chip is thinner than the thickness of the receiving substrate, and at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the second roller pair in a direction normal to the surface of the medium at the nip position of the second roller pair.

[0006] The image reading device of the present invention is characterized by including the medium transport device and a reading unit that is located downstream of the second roller pair in the transport direction and that reads an image on the medium. [Brief description of the drawings]

[0007] [Figure 1] FIG. [Diagram 2] A diagram of the scanner's document transport path viewed from the width direction. [Diagram 3] FIG. 4 is a block diagram showing a control system of the scanner. [Figure 4] FIG. 13 is a perspective view showing a state in which the second unit is opened relative to the first unit. [Diagram 5] Floor plan of the first unit. [Figure 6] FIG. 4 is a perspective view showing a state in which a cover provided on the first unit is attached. [Figure 7] FIG. 4 is a perspective view of the first unit with a cover removed. [Figure 8] FIG. 4 is a perspective view of the first unit as viewed from the rear side. [Figure 9] FIG. 4 is a perspective view showing a fixed state of the transmission board holder. [Figure 10] Floor plan of the second unit. [Figure 11] FIG. 4 is a perspective view showing a fixed state of the receiving board holder. [Figure 12] 4 is a perspective view showing the positional relationship between a first roller pair, a second roller pair, a third roller pair, and an ultrasonic detection unit. FIG. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. [Figure 16] FIG. [Figure 17] FIG. [Figure 18] FIG. [Figure 19] FIG. [Figure 20] FIG. [Figure 21] FIG. 3 is a cross-sectional view showing the structure of a transmitting sensor chip. [Figure 22] FIG. 2 is a cross-sectional view showing the configuration of an ultrasonic detection unit. [Figure 23] FIG. 4 is a diagram showing the positional relationship between an ultrasonic detection unit and a first roller pair. [Figure 24] 6A and 6B are diagrams showing the positional relationship between an ultrasonic detection unit and a second roller pair or a third roller pair. [Diagram 25] FIG. 4 is a diagram showing the configuration of a second roller pair. [Figure 26] FIG. 2 is a cross-sectional perspective view showing the structure of a first reading unit. [Figure 27] FIG. 4 is a diagram showing the positional relationship between the sensor substrate of the first reading unit, the transmitting sensor chip, and the transmitting substrate. [Figure 28] FIG. 4 is a diagram showing the positional relationship between the second reading unit, the receiving sensor chip, and the receiving substrate. [Figure 29] A diagram showing the occupied areas of a first roller pair, a second roller pair, a transport motor, a transmitting sensor chip, a transmitting board, a receiving sensor chip, and a receiving board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will now be briefly described. A medium transport device according to a first aspect is a medium transport device including a first roller pair that transports a medium in a transport direction, a second roller pair arranged downstream of the first roller pair in the transport direction, and an ultrasonic detection unit arranged between the first roller pair and the second roller pair in the transport direction, the ultrasonic detection unit including a transmitting sensor chip that emits ultrasonic waves along a first axis toward a first surface of the medium being transported, a receiving sensor chip that is arranged on the first axis at a position where the medium is sandwiched between the transmitting sensor chip and the receiving sensor chip and receives ultrasonic waves, and a transmitting substrate on which the transmitting sensor chip is provided, the transmitting sensor chip being disposed on a substrate surface. the first axis is inclined with respect to the surface of the medium passing between the transmitting sensor chip and the receiving sensor chip, the thickness of the transmitting sensor chip is thinner than the thickness of the transmitting substrate, the thickness of the receiving sensor chip is thinner than the thickness of the receiving substrate, and at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the second roller pair in a direction normal to the surface of the medium at the nip position of the second roller pair.

[0009] According to the present aspect, at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the second roller pair in the normal direction to the surface of the medium at the nip position of the second roller pair, thereby reducing the device dimensions in the normal direction to the surface of the medium at the nip position of the second roller pair.

[0010] A second aspect is an aspect dependent on the first aspect, characterized in that at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the first roller pair in a direction normal to the surface of the medium at the nip position of the first roller pair.

[0011] According to the present aspect, at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the first roller pair in the normal direction to the surface of the medium at the nip position of the first roller pair, thereby reducing the device dimensions in the normal direction to the surface of the medium at the nip position of the first roller pair.

[0012] A third aspect is an aspect dependent on the first aspect, and is characterized in that a third roller pair is provided downstream of the second roller pair in the transport direction, and at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the third roller pair in a normal direction to the surface of the medium at the nip position of the third roller pair.

[0013] According to the present aspect, at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the third roller pair in the normal direction to the surface of the medium at the nip position of the third roller pair, thereby reducing the device dimensions in the normal direction to the surface of the medium at the nip position of the third roller pair. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to the above-mentioned second aspect.

[0014] A fourth aspect is a dependent aspect of the first aspect, characterized in that the axis distance between the two rollers constituting the second roller pair is shorter than the distance between the transmitting sensor chip and the receiving sensor chip on the first axis.

[0015] According to this aspect, the axial distance between the two rollers constituting the second roller pair is shorter than the distance between the transmitting sensor chip and the receiving sensor chip on the first axis, so that the area occupied by the second roller pair in the direction along the axial distance can be reduced, thereby enabling the device dimensions to be reduced. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to the above-mentioned second or third aspect.

[0016] A fifth aspect is an aspect dependent on the first aspect, and is characterized in that a third roller pair is provided downstream of the second roller pair in the conveying direction, and the axis-to-axis distance between the two rollers constituting the third roller pair is shorter than the distance between the transmitting sensor chip and the receiving sensor chip on the first axis.

[0017] According to the present aspect, the axial distance between the two rollers constituting the third roller pair is shorter than the distance between the transmitting sensor chip and the receiving sensor chip on the first axis, so that the area occupied by the third roller pair in the direction along the axial distance can be reduced, thereby enabling the device dimensions to be suppressed. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to any of the above-mentioned second to fourth aspects.

[0018] The sixth aspect is a dependent aspect of the first aspect, and is characterized in that the distance between the axes of the two rollers constituting the first roller pair is shorter than the distance between the transmitting sensor chip and the receiving sensor chip on the first axis.

[0019] According to this aspect, the axial distance between the two rollers that make up the first roller pair is shorter than the distance between the transmitting sensor chip and the receiving sensor chip on the first axis, so that the area occupied by the first roller pair in the direction along the axial distance can be reduced, thereby enabling the device dimensions to be reduced. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to any of the above-mentioned second to fifth aspects.

[0020] A seventh aspect is an aspect dependent on the first aspect, characterized in that the transmitting substrate and the receiving substrate are inclined with respect to a normal direction to the surface of the medium passing between the transmitting sensor chip and the receiving sensor chip, the transmitting surface of the transmitting sensor chip is along the surface of the transmitting substrate, the receiving surface of the receiving sensor chip is along the surface of the receiving substrate, and at least a portion of the transmitting substrate and at least a portion of the receiving substrate are within the range of the second roller pair in the normal direction to the surface of the medium at the nip position of the second roller pair.

[0021] According to the present aspect, at least a portion of the transmitting substrate and at least a portion of the receiving substrate are within the range of the second roller pair in the normal direction to the surface of the medium at the nip position of the second roller pair, thereby enabling the device dimensions in the normal direction to the surface of the medium at the nip position of the second roller pair to be reduced. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to any of the above-mentioned second to sixth aspects.

[0022] An eighth aspect is an aspect dependent on the first aspect, and is characterized in that a third roller pair is provided downstream of the second roller pair in the conveying direction, and the path length between the first roller pair and the second roller pair is shorter than the path length between the second roller pair and the third roller pair.

[0023] According to this aspect, since the path length between the first roller pair and the second roller pair is shorter than the path length between the second roller pair and the third roller pair, the path length between the first roller pair and the second roller pair can be reduced, and thus the device dimensions can be reduced. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to any of the above-mentioned second to seventh aspects.

[0024] The ninth aspect is an aspect dependent on the first aspect, and is characterized in that it comprises a transmitting substrate holder that holds the transmitting substrate, a receiving substrate holder that holds the receiving substrate, a member that forms a media transport path between the first roller pair and the second roller pair, a transmitting side path forming member that fixes the transmitting substrate holder, and a receiving side path forming member that forms a media transport path between the first roller pair and the second roller pair, and fixes the receiving substrate holder.

[0025] According to the present aspect, since the transmitting board and the receiving board are each fixed to components forming a medium transport path, the distance between the medium and the transmitting sensor chip, and the distance between the medium and the receiving sensor chip, are stabilized, and thus the detection value of the ultrasonic wave is stabilized. Incidentally, this aspect is not limited to the above-mentioned first aspect, and may be subordinate to any of the above-mentioned second to eighth aspects.

[0026] A tenth aspect is an aspect dependent on the ninth aspect, characterized in that the transmitting substrate holder is provided with a first protective member arranged on the first axis and positioned between the transmitting sensor chip and a medium, and the receiving substrate holder is provided with a second protective member arranged on the first axis and positioned between the receiving sensor chip and a medium.

[0027] According to this aspect, since the transmitting substrate and the first protective member are provided on the transmitting substrate holder, the variation in the distance between the transmitting sensor chip and the first protective member can be suppressed, and as a result, multiple reflections of ultrasonic waves between the transmitting substrate and the first protective member can be appropriately suppressed. In addition, since the receiving board and the second protective member are provided in the receiving board holder, the variation in the distance between the receiving sensor chip and the second protective member can be suppressed, and as a result, multiple reflections of ultrasonic waves between the receiving sensor chip and the second protective member can be appropriately suppressed.

[0028] The image reading device of the 11th aspect is characterized in that it comprises the medium conveying device of any of the 1st to 10th aspects, and a reading unit located downstream of the second roller pair in the conveying direction and reading an image on the medium. According to this aspect, in the image reading device, the operational effects of any one of the first to tenth aspects described above can be obtained.

[0029] The twelfth aspect is a aspect dependent on the eleventh aspect, characterized in that the transmitting board and the receiving board have long sides and short sides and are arranged so that the short sides run along the transport direction, the reading unit has a glass plate that contacts the medium and guides the medium downstream, and the length of the short side of the transmitting board and the length of the short side of the receiving board are both shorter than the length of the glass plate in the transport direction.

[0030] According to this aspect, the transmitting board and the receiving board have long sides and short sides, and are arranged so that the short sides are aligned along the transport direction, so that the first roller pair and the second roller pair can be brought closer together in the transport direction, which contributes to miniaturizing the device. Since the length of the short side of the transmitting substrate and the length of the short side of the receiving substrate are both shorter than the length of the glass plate in the transport direction, the length of the short side in the transport direction can be reduced. As a result, the first roller pair and the second roller pair can be brought even closer to each other in the transport direction, which contributes to further miniaturization of the device.

[0031] A thirteenth aspect is an aspect dependent on the eleventh aspect, and is characterized in that the reading unit has a first reading unit that reads the first surface of the medium and a second reading unit that reads a second surface opposite to the first surface, the first reading unit has a reading sensor, and the transmitting sensor chip is located on the second reading unit side of the reading sensor in a normal direction to the surface of the medium facing the first reading unit.

[0032] According to this aspect, the transmitting sensor chip is positioned on the second reading unit side of the reading sensor in the normal direction relative to the surface of the medium facing the second reading unit, so that the amount by which the transmitting sensor chip protrudes from the first reading unit in the normal direction can be reduced, and the device dimensions in the normal direction can be reduced. Incidentally, this aspect is not limited to the eleventh aspect, and may be subordinate to the twelfth aspect.

[0033] A 14th aspect is an aspect dependent on the 11th aspect, and is characterized in that the reading unit has a first reading unit that reads the first surface of the medium and a second reading unit that reads the second surface of the medium, and at least a portion of the receiving sensor chip is within the range of the second reading unit in a normal direction to the surface of the medium facing the second reading unit.

[0034] According to this aspect, at least a portion of the receiving sensor chip is within the range of the second reading unit in the normal direction relative to the surface of the medium facing the second reading unit, and therefore the device dimensions in the normal direction can be reduced. Incidentally, this aspect is not limited to the eleventh aspect, but may be subordinate to the twelfth or thirteenth aspect.

[0035] The present invention will be specifically described below. In the following, as an example of an image reading device, a scanner 1 capable of reading at least one of a first side S1 and an opposite second side S2 of a document P, which is an example of a medium, is taken as an example. The scanner 1 is a so-called sheet-fed type scanner that reads the document P while moving it relative to a first reading unit 32 and a second reading unit 33, which will be described later. In this specification, the document P includes not only sheet-shaped documents, but also card-shaped documents and booklet-shaped documents. The scanner 1 can be regarded as a medium conveying device 100 from the viewpoint of conveying the document P, which is an example of a medium. In this case, the scanner 1 includes the medium conveying device 100, and a first reading unit 32 and a second reading unit 33, which will be described later.

[0036] In the XYZ coordinate system shown in each drawing, the X-axis direction is the width direction of the device and the width direction of the document, the Y-axis direction is the depth direction of the device, and the Z-axis direction is the vertical direction. In this embodiment, the +Y direction is the direction from the rear to the front of the device, and the -Y direction is the direction from the front to the rear of the device. Also, the left direction as viewed from the front of the device is the +X direction, and the right direction is the -X direction. In the following description, the direction in which the document P is transported may be referred to as "downstream," and the opposite direction may be referred to as "upstream."

[0037] <Scanner Overview> 1, the scanner 1 includes a device body 2 and a body support part 6 that supports the device body 2. The body support part 6 is placed on a placement surface GS of the device. The placement surface GS is, for example, a surface parallel to a horizontal plane. The device main body 2 is configured to include a first unit 3, a second unit 4, and a third unit 5.

[0038] The second unit 4 and the third unit 5 are provided rotatably relative to the first unit 3 around a rotation axis (not shown) parallel to the X-axis direction. The second unit 4 and the third unit 5 can rotate together with the first unit 3 around the rotation axis. Reference numeral 8a in FIG. 1 indicates an unlocking portion, and a user can unlock the second unit 4 and the third unit 5 from the first unit 3 by sliding the unlocking portion 8a in the -X direction. Then, by rotating the second unit 4 and the third unit 5 relative to the first unit 3, a part of the document transport path can be exposed (see FIG. 4). In particular, by opening the second unit 4 relative to the first unit 3, an upstream feed path R0, a downstream feed path R1, and a reading transport path R2, which will be described later, can be exposed.

[0039] Furthermore, the third unit 5 can rotate about a rotation axis (not shown) parallel to the X-axis direction relative to the first unit 3 and the second unit 4. By rotating the third unit 5 relative to the second unit 4, a U-turn discharge path R3 (see FIG. 2) downstream from a reading conveyance path R2 (described later) can be exposed. That is, the U-turn discharge path R3 is formed between the third unit 5 and the second unit 4.

[0040] Furthermore, the third unit 5 is held relative to the second unit 4 by a snap-fit ​​structure (not shown), and when the user applies an external force to the third unit 5, the third unit 5 is released from its position relative to the second unit 4, allowing the third unit 5 to be opened.

[0041] The device body 2 can rotate around a body rotation axis 6c (see FIG. 2) relative to the body support part 6, and in this embodiment, the device body 2 can hold two postures by rotating. The posture of the device body 2 shown in FIG. 2 is one of the two postures, and is a normal reading posture. Note that the device body 2 can take a booklet reading posture (not shown) by rotating from this normal reading posture so that the reading transport path R2 approaches horizontal.

[0042] 1, an operation unit 7 made up of a plurality of operation buttons is provided on the front surface of the device. In this embodiment, the plurality of operation buttons are made up of operation buttons 7a, 7b, and 7c, and user operations are accepted through these buttons.

[0043] <Scanner document transport path> Next, the document transport path in the scanner 1 will be described with reference to Fig. 2. In Fig. 2, the thick dashed line indicates the transport path along which the document P is transported. Reference symbol R0 denotes a conveying path upstream of the first roller pair 13, and is hereinafter referred to as an upstream feeding path R0. Reference symbol R1 denotes a conveying path between the first roller pair 13 and the second roller pair 16, which will hereinafter be referred to as a downstream feeding path R1. Reference symbol R2 denotes a transport path between the second roller pair 16 and the third roller pair 20, and is hereinafter referred to as a reading transport path R2. Note that the reading transport path R2 is a transport path facing a first reading unit 32 and a second reading unit 33, which will be described later. The first unit 3 constitutes the upstream feeding path R0, the downstream feeding path R1, and the lower side of the reading transport path R2, and the second unit 4 constitutes the upstream feeding path R0, the downstream feeding path R1, and the upper side of the reading transport path R2. Further, the reference symbol R3 denotes a conveying path that reverses upward from the third roller pair 20, and is hereinafter referred to as a U-turn discharge path R3. The U-turn discharge path R3 is formed between the second unit 4 and the third unit 5.

[0044] The normal reading position of the device body 2 (FIG. 2) is a position in which the reading transport path R2 is connected to the U-turn discharge path R3 by the flap 35. In the booklet reading position (not shown) of the device body 2, the flap 35 is in the position indicated by the two-dot chain line, the reading transport path R2 is not connected to the U-turn discharge path R3, and the document P is discharged from the reading transport path R2 in an obliquely downward direction including a +Y direction component and a -Z direction component. The normal reading position is suitable for reading a sheet-like document P, that is, a document P that has low rigidity and is easily bent. The booklet reading position is suitable for reading a document P that has high rigidity and is not easily bent, such as a plastic card or booklet.

[0045] The document transport path will be further explained below. The document P to be fed is supported in an inclined position by the document support section 11 and the document support 9. When multiple documents P are supported on the document support section 11, the topmost document P is sent downstream by the feed roller 14. The document support section 11 is formed in the upper opening / closing section 10. The upper opening / closing section 10 is rotatable around a rotation axis (not shown), and opens and closes the feed port by rotating. The document support 9 can be in a state where it is stored in the upper opening / closing part 10, or in a state where it is deployed from the upper opening / closing part 10. Fig. 1 shows a state where the upper opening / closing part 10 is closed, and Fig. 2 shows a state where the upper opening / closing part 10 is opened and the document support 9 is further deployed. The upper opening / closing part 10 and the document support 9 constitute a first unit 3. The scanner 1 employs a so-called center feed system, so that the center position of the document P in the X-axis direction, ie, in the width direction, is consistent regardless of the size of the document P.

[0046] The feed roller 14 and the separation roller 15 form a first roller pair 13 . The feed roller 14 is provided in the second unit 4. The feed roller 14 rotates by receiving power from a transport motor 47 (see FIG. 3). A separation roller 15 is provided in the first unit 3 at a position facing the feed roller 14. A rotation torque is imparted to the separation roller 15 by a torque limiter 15b (see FIG. 6) to prevent double feeding of the document P. In addition, in this embodiment, the feed roller 14 is provided above the original P placed on the original support section 11, and the topmost original P is fed first, but the feed roller 14 may be provided below the original P placed on the original support section 11, and the bottommost original P is fed first.

[0047] An ultrasonic detection unit 50 is provided on the downstream feeding path R1 downstream of the first roller pair 13. The ultrasonic detection unit 50 includes a transmission unit 50A and a reception unit 50B disposed opposite each other across the downstream feeding path R1. The control unit 80 (see FIG. 3) can detect double feeding of the document P based on a signal transmitted from the reception unit 50B. In addition, the positions, sizes, and shapes of the transmitting unit 50A and the receiving unit 50B are shown conceptually in FIG. 2, and the details thereof will be explained again later with reference to FIG. 4 and subsequent figures. In this embodiment, the transmitting unit 50A is arranged below the downstream feed path R1 and the receiving unit 50B is arranged above the downstream feed path R1, but this is not limited to this, and the receiving unit 50B may be arranged below the downstream feed path R1 and the transmitting unit 50A may be arranged above the downstream feed path R1.

[0048] A second roller pair 16 is provided downstream of the feed roller 14 and the separation roller 15. The second roller pair 16 is composed of a second lower roller 17 provided in the first unit 3, and a second upper roller 18 provided in the second unit 4. The second upper roller 18 is provided so as to be able to advance and retreat relative to the second lower roller 17, and is pressed against the second lower roller 17 by a pressing member (not shown), for example a coil spring. This causes the second upper roller 18 to advance and retreat relative to the second lower roller 17 depending on the thickness of the document P being transported. Both the second lower roller 17 and the second upper roller 18 are rotated by receiving power from a conveying motor 47 (see FIG. 3). When the second unit 4 is closed relative to the first unit 3, the second lower roller 17 and the second upper roller 18 come into contact with each other. When the second unit 4 is opened relative to the first unit 3, the second upper roller 18 moves away from the second lower roller 17.

[0049] A first reading section 32 and a second reading section 33 are disposed facing each other downstream of the second roller pair 16. The first reading section 32 is provided in the first unit 3, and the second reading section 33 is provided in the second unit 4. The first reading unit 32 reads the bottom surface, i.e., the first surface S1, of the document P supported by the document support unit 11, and the second reading unit 33 reads the top surface, i.e., the second surface S2, of the document P supported by the document support unit 11. The second reading unit 33 is provided so as to be movable toward and away from the first reading unit 32, and is pressed toward the first reading unit 32 by a pressing spring 34, which is an example of a pressing member. This causes the second reading unit 33 to move toward and away from the first reading unit 32 depending on the thickness of the document P being transported. In this embodiment, the first reading unit 32 and the second reading unit 33 are configured as contact image sensor modules (CISMs).

[0050] A third roller pair 20 is provided downstream of the first reading unit 32 and the second reading unit 33. The third roller pair 20 is composed of a third lower roller 21 provided in the first unit 3, and a third upper roller 22 provided in the second unit 4. The third upper roller 22 is provided so as to be able to advance and retreat relative to the third lower roller 21, and is pressed against the third lower roller 21 by a pressing member (not shown), for example a coil spring. Both the third lower roller 21 and the third upper roller 22 receive power from a transport motor 47 (see FIG. 3) and rotate. When the second unit 4 is closed relative to the first unit 3, the third lower roller 21 and the third upper roller 22 come into contact with each other. When the second unit 4 is opened relative to the first unit 3, the third upper roller 22 moves away from the third lower roller 21.

[0051] A flap 35 is provided downstream of the third roller pair 20. The flap 35 switches the document transport path as described above by rotating. In this embodiment, the flap 35 is configured to rotate in conjunction with the change in posture of the device body 2. In this embodiment, the flap 35 is configured to rotate in conjunction with the change in posture of the device body 2 by a linking mechanism (not shown), for example a cam mechanism, which mechanically rotates in conjunction with the posture of the device body 2. However, the flap 35 may be configured to rotate by a solenoid (not shown). In this case, the control unit 80 (see FIG. 3), which performs various controls, drives the solenoid to rotate the flap 35 based on detection information from a posture detection sensor (not shown).

[0052] A fourth roller pair 24 and a fifth roller pair 28 are provided on the U-turn discharge path R3. The fourth roller pair 24 is composed of a fourth driving roller 25 provided in the third unit 5 and a fourth driven roller 26 provided in the second unit 4. The fourth driven roller 26 is provided so as to be movable toward and away from the fourth driving roller 25, and is pressed toward the fourth driving roller 25 by a pressing member (not shown), for example a coil spring. This causes the fourth driven roller 26 to move toward and away from the fourth driving roller 25 depending on the thickness of the document P being transported. The fourth driving roller 25 is driven by a transport motor 47 (see FIG. 3). The fourth driven roller 26 is a roller that is driven to rotate.

[0053] The fifth roller pair 28 is composed of a fifth driving roller 29 provided in the third unit 5 and a fifth driven roller 30 provided in the second unit 4. The fifth driven roller 30 is provided so as to be movable toward and away from the fifth driving roller 29, and is pressed toward the fifth driving roller 29 by a pressing member (not shown), for example a coil spring. This causes the fifth driven roller 30 to move toward and away from the fifth driving roller 29 depending on the thickness of the document P being transported. The fifth driving roller 29 is driven by a transport motor 47 (see FIG. 3). The fifth driven roller 30 is a roller that is driven to rotate.

[0054] When the third unit 5 is closed relative to the second unit 4, the fourth driving roller 25 and the fourth driven roller 26 come into contact, and the fifth driving roller 29 and the fifth driven roller 30 also come into contact. When the third unit 5 is opened relative to the second unit 4, the fourth driving roller 25 and the fourth driven roller 26 move apart, and the fifth driving roller 29 and the fifth driven roller 30 also move apart. The document P discharged from the U-turn discharge path R3 is discharged obliquely upward including a -Y direction component by the fifth roller pair 28, and is supported by the upper surface 4a of the second unit 4 in an inclined posture.

[0055] 2 indicates the normal direction to the first surface S1 and the opposite second surface S2 of the document P at the document nip position of the first roller pair 13. In addition, since the first surface S1 and the opposite second surface S2 of the document P are parallel in most cases, in the following, when there is no need to distinguish between the two, they will be collectively referred to as the document surface S. Also, arrow Da2 indicates a normal direction to document surface S of document P that passes between transmission unit 50A and reception unit 50B of ultrasonic detection section 50. An arrow Da3 indicates a normal direction to the document surface S at the document nip position of the second roller pair 16. Moreover, the arrow Da4 indicates a normal direction to the document surface S of the document P passing between the first reading unit 32 and the second reading unit 33. An arrow Da5 indicates a normal direction to the document surface S at the document nip position of the third roller pair 20. In this embodiment, the differences between the normal directions Da1, Da2, Da3, Da4, and Da5 are slight, and as an example, the difference between the maximum angle and the minimum angle is within 5°. Therefore, hereinafter, when there is no need to distinguish between the normal directions, they will be referred to as normal direction Da. 2, the direction indicated by the arrow Fp is a direction perpendicular to the normal direction Da and indicates the direction in which the document P is transported. Hereinafter, this direction will be referred to as the transport direction Fp. In addition, in Figure 4 and subsequent figures, the X-Fp-Da coordinate system will be used in some cases.

[0056] <Scanner control system> Next, the control system of the scanner 1 will be described with reference to FIG. The control unit 80 includes a calculation unit 81 including a CPU (Central Processing Unit) and the like, and a storage unit 85 including a non-volatile memory or a volatile memory. The first reading unit 32, the second reading unit 33, the transport motor 47, and the ultrasonic detection unit 50 are connected to the control unit 80, and the control unit 80 controls these. The transport motor 47 is the drive source for the feed roller 14, the second lower roller 17, the second upper roller 18, the third lower roller 21, the third upper roller 22, the fourth drive roller 25, and the fifth drive roller 29.

[0057] The control unit 80 is connected to an interface unit 86, and receives various data and signals input from an external device 87 such as a personal computer, and outputs data read by the scanner 1 to the external device 87.

[0058] In the storage unit 85, various data and various programs for controlling the scanner 1 are recorded. The calculation unit 81 reads and executes various programs stored in the storage unit 85, thereby functioning as a transport control unit 82, a reading control unit 83, a multiple feed determination unit 84, and the like.

[0059] The transport control unit 82 controls the transport motor 47 to rotate the above-mentioned rollers, thereby feeding, transporting, and discharging the document P. The reading control unit 83 controls the first reading unit 32 and the second reading unit 33 while the document P is being transported, and causes them to read the image of the document P.

[0060] The multifeed determining section 84 is a state detecting section that detects the state of the document P, and in this embodiment, determines whether or not the document P has been multifeeded based on a reception signal input from a receiving circuit 59 (described later). Specifically, when the voltage value of the above-mentioned reception signal is smaller than a predetermined threshold value, it is determined that the document P is being fed in multiples. When the multiple feed determination unit 84 determines that multiple feed has occurred, the transport control unit 82 stops transporting the document P.

[0061] <Basic configuration of ultrasonic detection unit> Next, the basic configuration of the ultrasonic detection unit 50 will be described. 22, the ultrasonic detection unit 50 is configured to include a pair of ultrasonic elements. One of the pair of ultrasonic elements is a transmitting sensor chip 53, which transmits ultrasonic waves. The other of the pair of ultrasonic elements is a receiving sensor chip 56, which receives ultrasonic waves. The transmitting sensor chip 53 and the receiving sensor chip 56 are arranged opposite to each other on a sensor central axis Lx, which is an example of a first axis, with the document P transported along the downstream feeding path R1 sandwiched therebetween.

[0062] In this ultrasonic detection unit 50, ultrasonic waves are emitted from the transmitting sensor chip 53 toward the first surface S1 of the document P being fed. The ultrasonic waves emitted from the transmitting sensor chip 53 are input to the document P, and the ultrasonic waves that have passed through the document P are received by the receiving sensor chip 56. When the ultrasonic waves are received by the receiving sensor chip 56, a reception signal corresponding to the sound pressure of the received ultrasonic waves is output, and multi-feeding of the document P is determined based on the signal strength of this reception signal.

[0063] The sensor central axis Lx is an axis passing through the center of the transmitting sensor chip 53 and the center of the receiving sensor chip 56, and corresponds to the transmission and reception direction of ultrasonic waves. The sensor central axis Lx is perpendicular to the transmitting surface 53a, which is the upper surface of the transmitting sensor chip 53, and the receiving surface 56a, which is the upper surface of the receiving sensor chip 56. The sensor central axis Lx is inclined with respect to the document surface S of the document P at an angle β. Here, when the sensor central axis Lx coincides with the normal direction of the document surface S, that is, when the angle β is 90°, there is a risk that the ultrasonic waves transmitted from the transmitting sensor chip 53 will be multiple-reflected between the document P and the transmitting sensor chip 53. Also, there is a risk that the ultrasonic waves that have passed through the document P will be multiple-reflected between the receiving sensor chip 56 and the document P. In this case, in addition to the ultrasonic waves that pass through the document P from the transmitting sensor chip 53 and are received by the receiving sensor chip 56, the receiving sensor chip 56 will receive ultrasonic waves that have been multiple-reflected between the document P and the transmitting sensor chip 53 and ultrasonic waves that have been multiple-reflected between the receiving sensor chip 56 and the document P, and therefore accurate double feed detection will not be possible.

[0064] In contrast, by tilting the sensor central axis Lx with respect to the normal to the document surface S of the document P, reception of unnecessary ultrasonic components such as multiply reflected ultrasonic waves can be reduced, enabling highly accurate detection of double feed. Incidentally, the angle β can be set to a value between 60° and 80°, and is set to 70° in this embodiment.

[0065] In addition, when the area of ​​the transmission surface 53a of the transmitting sensor chip 53 is small, the beam diameter of the ultrasonic wave is small. In this case, when the distance between the transmitting sensor chip 53 and the receiving sensor chip 56, i.e., the distance along the sensor central axis Lx, is short, the sound pressure of the ultrasonic wave is greatly reduced when the transmitting sensor chip 53 is displaced from the sensor central axis Lx due to an installation error. Similarly, when the area of ​​the receiving surface 56a of the receiving sensor chip 56 is small, the sound pressure is also greatly reduced when the transmitting sensor chip 53 is displaced from the sensor central axis Lx. Therefore, it is preferable to secure a certain distance between the transmitting sensor chip 53 and the receiving sensor chip 56, but if the distance between the transmitting sensor chip 53 and the receiving sensor chip 56 is too long, this also leads to a decrease in sound pressure. In this embodiment, in consideration of the above-mentioned viewpoint, the distance along the sensor central axis Lx between the transmitting sensor chip 53 and the receiving sensor chip 56, ie, the sensor-to-sensor distance, is set in the range of 15.0 mm to 30.0 mm, for example, to 24.9 mm.

[0066] <Sensor chip configuration> The configuration of the ultrasonic detection unit 50 will be further described. As shown in FIG. 3, the transmitting board 52 is provided with a transmitting circuit 58 that controls the transmitting sensor chip 53, and the receiving board 55 is provided with a receiving circuit 59 that controls the receiving sensor chip .

[0067] Now, with reference to FIG. 21, the configuration of the transmitting sensor chip 53 will be described. The transmitting sensor chip 53 includes a base substrate 213 , an element substrate 210 , and a piezoelectric element 220 . The element substrate 210 includes a substrate main body 211 and a diaphragm 212 provided on one surface of the substrate main body 211. In the following description, the substrate thickness direction of the element substrate 210 is defined as the G direction. The G direction is a direction in which ultrasonic waves are transmitted, and is parallel to the sensor central axis Lx. The substrate main body 211 is a substrate provided on the diaphragm 212, and is made of a semiconductor substrate such as Si. The substrate main body 211 is provided with an opening 211A penetrating the substrate main body 211 along the G direction. The diaphragm 212 is supported by a base substrate 213. The diaphragm 212 and the base substrate 213 are fixed by adhesion. A space for disposing a piezoelectric element 220 is provided between the base substrate 213 and the diaphragm 212. The diaphragm 212 may be fixed to the base substrate 213 in a laminated state.

[0068] The diaphragm 212 is made of SiO2 or a laminate of SiO2 and ZrO2, and is provided on the -G side of the substrate main body 211. The diaphragm 212 closes the -G side of the opening 211A. The portion of the diaphragm 212 that overlaps with the opening 211A when viewed from the G direction forms the vibrating part 212A.

[0069] The piezoelectric element 220 is provided on the vibration plate 212 at a position overlapping with each vibration portion 212A when viewed from the G direction. The piezoelectric element 220 is configured by laminating a first electrode 221, a piezoelectric film 222, and a second electrode 223 in this order on the vibration plate 212.

[0070] Here, one ultrasonic transducer Tr is configured by one vibration part 212A and a piezoelectric element 220 provided on the vibration part 212A. Although not shown in the drawings, in this embodiment, such ultrasonic transducers Tr are arranged in a two-dimensional array structure to configure the transmitting sensor chip 53. The transmitting circuit 58 (see FIG. 3) is electrically connected to each ultrasonic transducer Tr of the transmitting sensor chip 53, and generates a drive signal for driving each ultrasonic transducer Tr.

[0071] In the transmitting sensor chip 53, a pulse wave voltage of a predetermined frequency is applied between the first electrode 221 and the second electrode 223 of each ultrasonic transducer Tr, whereby the piezoelectric film 222 expands and contracts. This causes the vibration part 212A to vibrate at a frequency according to the opening width of the opening 211A, etc., and ultrasonic waves are transmitted from the vibration part 212A toward the +G side along the sensor central axis Lx. In other words, the surface of the element substrate 210 on the +G side becomes the ultrasonic transmission surface 53a of the transmitting sensor chip 53.

[0072] The base substrate 213 of the transmitting sensor chip 53 is attached to the transmitting substrate 52 via a resist using a non-conductive adhesive. At least one of a chip tilt prevention pad (not shown) for preventing the transmitting sensor chip 53 from tilting relative to the transmitting substrate 52, a positioning mark (not shown) for the transmitting sensor chip 53 relative to the transmitting substrate 52, and an adhesive leakage prevention part (not shown) for preventing the non-conductive adhesive from overflowing is provided on the transmitting substrate 52. Furthermore, the transmitting sensor chip 53 is attached to the transmitting substrate 52 with silver paste at a position different from that of the chip tilt prevention pad (as shown in the attached figure), and the chip tilt prevention pad (not shown) is not used for conduction.

[0073] Although the configuration of the receiving sensor chip 56 is not shown, the receiving sensor chip 56 has the same configuration as the transmitting sensor chip 53 described above. In this case, the surface on the +G side of the element substrate 210 becomes the ultrasonic wave receiving surface 56a of the receiving sensor chip 56. When the ultrasonic wave reaches the ultrasonic transducer Tr, the diaphragm 212 vibrates according to the sound pressure of the ultrasonic wave. The vibration of the diaphragm 212 deforms the piezoelectric film 222, and a potential difference occurs between the first electrode 221 and the second electrode 223. As a result, a reception signal according to the sound pressure of the received ultrasonic wave is output from the first electrode 221 of the ultrasonic transducer Tr. In other words, the ultrasonic wave is detected. A general circuit for processing the received signal input by receiving ultrasonic waves can be used as the receiving circuit 59 (FIG. 3) for processing the received signal. For example, the receiving circuit 59 can be composed of a band pass filter, an amplifier, a sample and hold circuit, a comparator, etc. (not shown).

[0074] <Configuration of the transmitting sensor unit and the receiving sensor unit> Next, the configurations of the transmitting unit 50A and the receiving unit 50B will be described. 4 shows a state in which the second unit 4 is opened relative to the first unit 3. When the second unit 4 is opened relative to the first unit 3, the inside of the first unit 3 and the inside of the second unit 4 are exposed. A transmission-side path forming member 36 is provided inside the first unit 3, and when the second unit 4 is opened relative to the first unit 3, the transmission-side path forming member 36 is exposed. Furthermore, a receiving path forming member 39 is provided inside the second unit 4, and when the second unit 4 is opened relative to the first unit 3, the receiving path forming member 39 is exposed. The transmitting path forming member 36 and the receiving path forming member 39 form a part of the upstream feeding path R0, a downstream feeding path R1, and a reading transport path R2.

[0075] As shown in Fig. 5, a cover 37 is provided on the transmission-side path forming member 36. Cover 37 is detachably provided on the transmission-side path forming member 36 so that it can be in an attached state as shown in Fig. 5 and Fig. 6 and in a removed state as shown in Fig. 7. Cover 37 is attached to the transmission-side path forming member 36 by a snap-fit ​​structure (not shown). A circular opening 37a is formed in the cover 37, and the sensor central axis Lx of the ultrasonic detection unit 50 passes near the center of the opening 37a. A part of a first protective member 70, which will be described later, is exposed inside the opening 37a.

[0076] A transmitting unit 50A is provided inside the cover 37, and when the cover 37 is removed, the transmitting unit 50A is exposed as shown in Fig. 7. Note that even when the cover 37 is attached as shown in Fig. 6, a part of the transmitting unit 50A is exposed, but when the cover 37 is opened, an even larger part of the transmitting unit 50A is exposed. When the cover 37 is attached as shown in Fig. 6, a part of a first wall portion 60b of a transmitting board holder 60, which will be described later, is exposed.

[0077] Furthermore, a roller holding member 38 that holds the separation roller 15 is provided inside the cover 37. When the cover 37 is removed, the roller holding member 38 can be removed, and thus the separation roller 15 can be replaced together with the roller holding member 38. In FIG. 6, reference numeral 15a denotes a rotation shaft of the separation roller 15, and reference numeral 15b denotes a torque limiter that imparts a separation torque to the separation roller 15.

[0078] In addition, in Figure 5, symbol Ba1 is the distance between the center of the rotation axis of the separation roller 15 and the center of the rotation axis of the second lower roller 17, i.e., the inter-axis distance, and symbol Ba2 is the distance between the center of the rotation axis of the second lower roller 17 and the center of the rotation axis of the third lower roller 21, i.e., the inter-axis distance. In this embodiment, the center distance Ba1 is shorter than the center distance Ba2. In other words, the path length of the downstream feeding path R1 is shorter than the path length of the reading transport path R2. In this embodiment, the center distance Ba1 is 29.1 mm, and the center distance Ba2 is 34.0 mm.

[0079] 8, a transport motor 47 and a main board 48 are provided on the -Da direction side of the transmission-side path forming member 36. The transport motor 47 is provided at the end of the transmission-side path forming member 36 in the -X direction on the rear side thereof. The main board 48 constitutes the above-mentioned control unit 80. Between the main board 48 and the transmission side path forming member 36, a transmission unit 50A is provided as shown in FIG. The configuration of the transmitting unit 50A will be described in detail later, but the transmitting unit 50A has a transmitting board holder 60 as its base, and this transmitting board holder 60 is fixed to the transmitting side path forming member 36 by screws 61, 61.

[0080] 10, a circular opening 39a is formed in the receiving path forming member 39, and the sensor central axis Lx of the ultrasonic detection unit 50 passes near the center of the opening 39a. A part of a second protective member 73, which will be described later, is exposed inside the opening 39a. In addition, in Figure 10, symbol Bb1 is the distance between the center of the rotation axis of the feed roller 14 and the center of the rotation axis of the second upper roller 18, i.e., the inter-axis distance, and symbol Bb2 is the distance between the center of the rotation axis of the second upper roller 18 and the center of the rotation axis of the third upper roller 22, i.e., the inter-axis distance. In this embodiment, the center distance Bb1 is shorter than the center distance Bb2. In other words, the path length of the downstream feeding path R1 is shorter than the path length of the reading transport path R2. In this embodiment, the center distance Bb1 is 30.0 mm, and the center distance Bb2 is 34.0 mm.

[0081] As shown in FIG. 11, a receiving unit 50B is provided on the +Da side of the receiving side path forming member 39. Although the configuration of the receiving unit 50B will be described in detail later, the receiving unit 50B has a receiving board holder 62 as its base, and a fixed portion 62j, which is a part constituting this receiving board holder 62, is fixed to the receiving side path forming member 39 by a receiving side holder fixing screw 63. Note that reference numeral 39b denotes a positioning portion provided on the receiving side path forming member 39, and the positioned portion 62k is positioned relative to the receiving side path forming member 39 by fitting a hole portion 62e provided on the positioned portion 62k of the receiving board holder 62 into the positioning portion 39b. As a result of the above, the receiving board holder 62 is positioned and fixed to the receiving side path forming member 39 .

[0082] Next, the configurations of the transmitting unit 50A and the receiving unit 50B will be further described with reference to FIG. 12 and subsequent figures. 12, the ultrasonic detection unit 50 is disposed in the space between the first roller pair 13 and the second roller pair 16. Along the conveying direction Fp, the separation roller 15 constituting the first roller pair 13, the transmission unit 50A, the second lower roller 17 constituting the second roller pair 16, and the third lower roller 21 constituting the third roller pair 20 are disposed in this order. Also, along the conveying direction Fp, the feed roller 14 constituting the first roller pair 13, the reception unit 50B, the second upper roller 18 constituting the second roller pair 16, and the third upper roller 22 constituting the third roller pair 20 are disposed in this order.

[0083] As shown in FIGS. 13 and 14, the transmission unit 50A is configured by providing a transmission board 52 and a first protective member 70 on a transmission board holder 60. Similarly, the receiving unit 50B is configured by providing a receiving board 55 and a second protective member 73 on a receiving board holder 62.

[0084] 17 and 18, the transmission board holder 60 has screw holes 60e in the screw fixing parts 60j, 60k, and the screws 61 described with reference to Fig. 9 are passed through the screw holes 60e. Between the screw fixing parts 60j and 60k, the fixing part 60a is formed so as to be located in the +Da direction from the screw fixing parts 60j, 60j. The fixing part 60a is a part for fixing the first protective member 70, and a first opening 60f is formed in the center (see Figs. 17, 18, and 22). The first opening 60f is formed so that the sensor central axis Lx of the ultrasonic detection unit 50 passes near the center of the first opening 60f.

[0085] Protective member positioning portions 60c, 60c are formed on the surface of the fixed portion 60a. The first protective member 70 is held by a first holding member 71 as shown in Fig. 19, and recesses 71a, 71a are formed in the first holding member 71. The recesses 71a, 71a fit into the protective member positioning portions 60c, 60c, whereby the first holding member 71, i.e., the first protective member 70, is positioned relative to the fixed portion 60a.

[0086] A cylindrical protrusion 60m is formed on the rear side of the fixing portion 60a as shown in Fig. 18, and a screw hole 60g is formed in the protrusion 60m. Also, a board positioning portion 60d is formed on the rear side of the fixing portion 60a as shown in Fig. 14. An opening 52a and a recess 52b are formed in the transmitting board 52 as shown in Fig. 15. The opening 52a fits over a protrusion 60m of the transmitting board holder 60, and the recess 52b fits over a board positioning portion 60d of the transmitting board holder 60, thereby positioning the transmitting board 52 with respect to the transmitting board holder 60. Then, as shown in Fig. 14, the transmitting board fixing screw 54 fits into the screw hole 60g (Fig. 18), thereby fixing the transmitting board 52 to the transmitting board holder 60.

[0087] The transmitting board holder 60 holds the transmitting board 52 so that the transmitting surface 53a of the transmitting sensor chip 53 is inclined at an angle α1 with respect to the document surface S as shown in Fig. 22. As a result, the transmitting surface 53a of the transmitting sensor chip 53 and the receiving surface 56a of the receiving sensor chip 56 are parallel to each other, and the sensor central axis Lx is inclined at an angle β with respect to the document surface S.

[0088] Furthermore, a first wall portion 60b is formed upstream of the fixed portion 60a in the transport direction Fp, as shown in Figures 13, 14, 17, and 18, and a second wall portion 60h is formed downstream of the fixed portion 60a in the transport direction Fp. The first wall portion 60b is located in a position that is visible from the outside when the cover 37 is closed as shown in FIG. 6, and serves to protect the transmission board 52 from foreign objects, liquids, and the like. Although not shown in the drawing, when the first wall portion 60b is viewed from the upstream in the transport direction Fp, it is located so as to overlap with a part of the transmitting substrate 52 and the entire transmitting sensor chip 53. In other words, when the first wall portion 60b is viewed from the upstream in the transport direction Fp, a part of the transmitting substrate 52 and the entire transmitting sensor chip 53 are located so as to be hidden by the first wall portion 60b.

[0089] Next, the receiving board holder 62 has the fixed part 62j and the positioned part 62k described with reference to Fig. 11, and the fixing part 62a is formed between the fixed part 62j and the positioned part 62k so as to be located in the -Da direction from the fixed part 62j and the positioned part 62k. The fixing part 62a is a part for fixing the second protective member 73, and a second opening 62f is formed in the center (see Fig. 22), and the second opening 62f is formed so that the sensor central axis Lx of the ultrasonic detection unit 50 passes near the center of the second opening 62f.

[0090] 14, protective member positioning portions 62c, 62c are formed on the surface of the fixed portion 62a. The second protective member 73 is held by a second holding member 74, and recesses 74a, 74a are formed in the second holding member 74. The recesses 74a, 74a fit into the protective member positioning portions 62c, 62c, whereby the second holding member 74, i.e., the second protective member 73, is positioned with respect to the fixed portion 62a.

[0091] A protruding board positioning portion 62d is formed on the back side of the fixing portion 62a as shown in FIG. 13. A recess 55b is formed in the receiving board 55. The recess 55b fits into the board positioning portion 62d. Although not shown, the receiving board holder 62 has a protrusion and a screw hole similar to the protrusion 60m and the screw hole 60g of the transmitting board holder 60, respectively. The receiving board 55 has an opening similar to the opening 52a of the transmitting board 52 (see FIG. 15). The receiving board 55 is positioned relative to the receiving board holder 62 by fitting this opening into the protrusion of the receiving board holder 62 and fitting the recess 55b of the receiving board 55 into the board positioning portion 62d of the receiving board holder 62. The receiving board 55 is fixed to the receiving board holder 62 by fitting the receiving board fixing screw 57 into the screw hole as shown in FIG. 13.

[0092] The receiving board holder 62 holds the receiving board 55 so that the receiving surface 56a of the receiving sensor chip 56 is inclined at an angle α1 with respect to the document surface S as shown in Fig. 22. As a result, the receiving surface 56a of the receiving sensor chip 56 and the transmitting surface 53a of the transmitting sensor chip 53 are parallel to each other, and the sensor central axis Lx is inclined at an angle β with respect to the document surface S.

[0093] As described above, in this embodiment, the transmitting board 52 is fixed to the transmitting side path forming member 36, which is a member that forms the document transport path, via the transmitting board holder 60, and the receiving board 55 is fixed to the receiving side path forming member 39, which is a member that forms the document transport path, via the receiving board holder 62. This stabilizes the distance between the document P and the transmitting sensor chip 53, and the distance between the document P and the receiving sensor chip 56, and therefore stabilizes the detection value of the ultrasonic waves.

[0094] Next, the configuration of the transmission board 52 will be described. 13 to 15, the transmitting board 52 is a rectangular board having short sides E1 and long sides E2, and the recess 52b is formed in one of the short sides E1 as described above. The transmitting board 52 is provided so that the short side E1 is aligned with the transport direction Fp. The transmitting sensor chip 53 is placed and fixed on the substrate surface 52d of the transmitting substrate 52, and no other members such as a base are interposed between the transmitting sensor chip 53 and the substrate surface 52d, except for an adhesive.

[0095] A connector 52c is provided on the opposite side of the transmission board 52 relative to the board surface 52d, and a transmission side cable 76 (see FIGS. 13 and 14) is connected to this connector 52c. Further, a first enclosing member 65 is provided on the board surface 52d of the transmitting board 52. In this embodiment, the first enclosing member 65 is made of a metal plate material and is fixed to the transmitting board 52 by an adhesive. An opening 65a is formed in the first enclosing member 65, and the opening 65a is formed so that the sensor central axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the opening 65a. The first enclosing member 65 is provided along the substrate surface 52d as shown in FIG.

[0096] The transmitting board fixing screw 54 includes a head portion having a driver fitting hole, a threaded portion having a male thread, and a tip portion at the end of the male thread. The threaded portion is attached to a mounting portion on the same side as the transmitting sensor chip 53 with respect to the board surface 52d of the transmitting board 52, specifically, to the threaded hole 60g (see Figs. 18 and 22). Note that the threaded portion may also be attached to a mounting portion on the opposite side of the board surface 52d of the transmitting board 52 to the transmitting sensor chip 53, i.e., to the threaded hole. When the transmitting board 52 is fixed to the transmitting board holder 60, the position of the tip 54a of the transmitting board fixing screw 54 is located in the -Da direction from the position 65b of the first enclosing member 65 which is furthest in the +Da direction in the normal direction Da. In addition, the direction along the sensor center axis Lx from the transmitting unit 50A to the receiving unit 50B is defined as the +Lx direction, and the opposite direction is defined as the -Lx direction; when the transmitting board 52 is fixed to the transmitting board holder 60, the position of the tip 54a of the transmitting board fixing screw 54 is located in the +Lx direction relative to the first enclosing member 65. In addition, the distance from the board surface 52d of the transmission board 52 to the first enclosing member 65 is shorter than the length of the threaded portion of the transmission board fixing screw .

[0097] 16, reference symbol t0 denotes the total thickness of the transmitting substrate 52 and the transmitting sensor chip 53, reference symbol t1 denotes the thickness of the transmitting substrate 52, and reference symbol t2 denotes the thickness of the transmitting sensor chip 53. The thickness t2 of the transmitting sensor chip 53 is thinner than the thickness of the transmitting substrate 52. For example, the thickness of the transmitting substrate 52 may be 0.8 to 1.2 mm, and particularly 1.0 mm, and for example, the thickness of the transmitting sensor chip 53 may be 0.5 to 0.7 mm, and particularly 0.578 mm. As an example, the distance from the board surface 52d of the transmitting board 52 to the first enclosing member 65 can be set to 1.2 to 1.6 mm, and in particular, 1.4 mm.

[0098] As is clear from FIGS. 13 and 14, the receiving board 55 has a similar configuration to the transmitting board 52, and its shape and dimensions are also similar to those of the transmitting board 52. That is, the receiving board 55 is a rectangular board having a short side E1 and a long side E2, and is provided so that the short side E1 is aligned with the conveyance direction Fp. The receiving board 55 is provided with a connector 55c, to which a receiving side cable 77 is connected. Further, a second enclosing member 67 is provided on the substrate surface 55d of the receiving substrate 55 (see FIG. 22). The second enclosing member 67 is made of a metal plate and is fixed to the receiving substrate 55 by an adhesive. The second enclosing member 67 has an opening similar to the opening 65a of the first enclosing member 65, and the opening is formed so that the sensor central axis Lx of the ultrasonic detection unit 50 passes near the center of the opening. The second enclosing member 67 is provided along the substrate surface 55d. The thicknesses of the receiving substrate 55 and the receiving sensor chip 56 are similar to those of the transmitting substrate 52 and the transmitting sensor chip 53 described above, respectively.

[0099] The receiving board fixing screw 57 includes a head portion having a screwdriver fitting hole, a threaded portion having a male thread, and a tip portion at the end of the male thread. The threaded portion is attached to a mounting portion on the same side as the receiving sensor chip 56 with respect to the board surface 55d of the receiving board 55, specifically, the threaded hole 62g (see FIG. 22). Note that the threaded portion may also be attached to a mounting portion on the opposite side of the board surface 55d of the receiving board 55 to the receiving sensor chip 56, i.e., the threaded hole. When the receiving board 55 is fixed to the receiving board holder 62, the position of the tip 57a of the receiving board fixing screw 57 is located in the +Da direction from the position 67b of the second enclosing member 67 which is furthest in the -Da direction in the normal direction Da. Furthermore, when the receiving board 55 is fixed to the receiving board holder 62, the position of the tip 57a of the receiving board fixing screw 57 is located in the -Lx direction from the second enclosing member 67 in the axial direction of the sensor central axis Lx. Moreover, the distance from the board surface 55d of the receiving board 55 to the second enclosing member 67 is shorter than the length of the threaded portion of the receiving board fixing screw 57. For example, the distance from the board surface 55d of the receiving board 55 to the second enclosing member 67 may be set to 1.2 to 1.6 mm, and in particular, 1.4 mm.

[0100] As described above, the transmitting substrate 52 is provided with a first enclosing member which is a plate-shaped member that surrounds the transmitting sensor chip 53 and is arranged along the transmitting substrate 52, and the receiving substrate 55 is provided with a second enclosing member which is a plate-shaped member that surrounds the receiving sensor chip 56 and is arranged along the receiving substrate 55, so that the transmitting sensor chip 53 or the receiving sensor chip 56 can be protected from external forces.

[0101] <Configuration of the first protective member and the second protective member> Next, the first protective member 70 and the second protective member 73 will be described in detail. In this embodiment, the first protective member 70 and the second protective member 73 are made of the same material, and the second holding member 74 that holds the second protective member 73 is also made of the same material as the first holding member 71 that holds the first protective member 70. Therefore, in the following, we will explain the first protective member 70 and the first holding member 71, and omit the explanation of the second protective member 73 and the second holding member 74.

[0102] In this embodiment, the first protective member 70 is a filter formed in a mesh shape. Fig. 20 shows an enlarged view of a portion of the first protective member 70. In Fig. 20, the first protective member 70 is a filter configured in a mesh shape by intersecting wires 70a. Note that Fig. 20 shows an example in which the wires 70a intersect at 90°, but is not limited thereto, and the wires 70a may intersect at an angle other than 90°. The wire 70a may be made of metals such as copper, iron, brass, and SUS, alloys, and synthetic resins such as nylon and polyester. In the present embodiment, polyester is used as an example.

[0103] It is preferable that the wire diameter of the wire 70a is less than the wavelength of the ultrasonic wave, so that the problem of the ultrasonic wave being diffused by the wire 70a of the first protection member 70 is suppressed. In the first protective member 70, an opening 70b is formed between a pair of adjacent wires 70a. The opening 70b corresponds to a hole portion that allows ultrasonic waves to pass through. In order to prevent foreign matter such as paper powder from adhering to or accumulating on the transmitting surface 53a of the transmitting sensor chip 53 and the receiving surface 56a of the receiving sensor chip 56, it is preferable that the width of the opening 70b, i.e., the opening width Wa, is 1 mm or less. However, in this embodiment, the opening width Wa is set to 30 μm or less, for example 22 μm, so that the cleaning agent does not pass through the opening 70b when the device is cleaned with the cleaning agent. In addition, in Figures 12-14 and 19, the first protective member 70 and the second protective member 73 are shown in a mesh-like shape to clearly show that they are mesh-like members, but the crossing angle of the wires 70a and the opening width Wa are shown for convenience only.

[0104] As described above, since the first protective member 70 and the second protective member 73 are mesh-like members, ultrasonic waves can pass through the first protective member 70 and the second protective member 73 smoothly.

[0105] Since the opening width Wa of the mesh member is 30 μm or less, when the device is cleaned with a cleaning agent, it is possible to prevent the cleaning agent from adhering to the transmitting sensor chip 53 through the first protective member 70, or the cleaning agent from adhering to the receiving sensor chip 56 through the second protective member 73. As a result, the strength of the ultrasonic waves received by the receiving sensor chip 56 is reduced, and the malfunction of causing erroneous detection can be prevented.

[0106] 19, the above-described first protective member 70 is held by a first holding member 71 having an opening 71b that exposes the first protective member 70. The first protective member 70 is held by the first holding member 71 by being sandwiched between two first holding members 71. Double-sided tape (not shown) is used between the first protective member 70 and the first holding member 71, thereby integrating the first protective member 70 and the first holding member 71. The relationship between the second protective member 73 and the second holding member 74 is similar to the relationship between the first protective member 70 and the first holding member 71 described above.

[0107] Next, the first protective member 70 is held by the transmitting board holder 60 so as to be inclined at an angle α2 with respect to the document surface S, as shown in Fig. 22. Similarly, the second protective member 73 is held by the receiving board holder 62 so as to be inclined at an angle α2 with respect to the document surface S. As a result, the angle formed between the first protective member 70 and the second protective member 73 becomes 0°, that is, the first protective member 70 and the second protective member 73 are parallel to each other. In this embodiment, the angle α2 is set to an angle different from the angle α1, and specifically, the angle α2 is set to be smaller than the angle α1.

[0108] That is, if the angle α2 and the angle α1 are set to be the same angle, that is, if the transmitting surface 53a and the first protective member 70 are parallel to each other, multiple reflections of ultrasonic waves will occur between the transmitting surface 53a and the first protective member 70, and it may become difficult to accurately detect double feeding. The same applies to the case where the receiving surface 56a and the second protective member 73 are parallel to each other. However, since the angle α2 is set to a different angle from the angle α1 as described above, the multiple reflections can be suppressed and double feed detection can be performed appropriately. In this embodiment, as an example, the angle α1 is set to 20°, and the angle α2 is set to 15°.

[0109] Incidentally, the distance between the transmitting surface 53a and the first protective member 70 is also a factor in causing multiple reflections of ultrasonic waves. That is, if the distance between the transmitting surface 53a and the first protective member 70 is short, multiple reflections of ultrasonic waves will occur, and based on this viewpoint, in this embodiment, the distance between the transmitting surface 53a and the first protective member 70, i.e., the distance along the sensor central axis Lx, is set to 4.0 mm to 6.0 mm, and as an example, is set to 4.89 mm.

[0110] The first protective member 70 described above is held by the transmitting board holder 60 together with the transmitting board 52, and therefore it is possible to suppress variation in the distance between the transmitting sensor chip 53 and the first protective member 70. As a result, it is possible to appropriately suppress multiple reflections of ultrasonic waves between the transmitting sensor chip 53 and the first protective member 70. Similarly, since the second protective member 73 is held by the receiving board holder 62 together with the receiving board 55, it is possible to suppress variation in the distance between the receiving sensor chip 56 and the second protective member 73. As a result, multiple reflections of ultrasonic waves between the receiving sensor chip 56 and the second protective member 73 can be appropriately suppressed.

[0111] The transmission board holder 60 also has a first opening 60f that passes ultrasonic waves on the sensor central axis Lx, and the first protective member 70 is provided on the surface of the transmission board holder 60 so as to cover the first opening 60f. Similarly, the receiving substrate holder 62 has a second opening 62f that allows ultrasonic waves to pass on the sensor central axis Lx, and the second protective member 73 is provided on the surface of the receiving substrate holder 62 so as to cover the second opening 62f. This provides the following effects. If foreign matter remains attached to the first protective member 70 or the second protective member 73, the strength of the ultrasonic waves received by the receiving sensor chip 56 will decrease, which may lead to erroneous detection. In this case, therefore, it is necessary to replace the first protective member 70 or the second protective member 73 or to perform maintenance such as cleaning. In this embodiment, the first protective member 70 is provided on the surface of the transmission board holder 60 so as to cover the first opening 60f, making replacement and maintenance of the first protective member 70 easy. Similarly, since the second protective member 73 is provided on the surface of the receiving substrate holder 62 so as to cover the second opening 62f, replacement and maintenance of the second protective member 73 can be easily performed.

[0112] As described with reference to FIG. 22, the transmitting sensor chip 53 and the receiving sensor chip 56 are inclined at an angle α1 as a first angle with respect to the surface of the document P passing between the transmitting sensor chip 53 and the receiving sensor chip 56. Further, the first protective member 70 and the second protective member 73 are inclined at an angle α2 as a second angle with respect to the surface of the document P passing between the transmitting sensor chip 53 and the receiving sensor chip 56. The angle α1 and the angle α2 are different, and the angle α2 is gentler than the angle α1. This provides the following effects.

[0113] If the first protective member 70 and the second protective member 73 are parallel to the surface of the original P passing between the transmitting sensor chip 53 and the receiving sensor chip 56, paper dust and other foreign matter will easily adhere to the first protective member 70 and the second protective member 73. However, since the first protective member 70 and the second protective member 73 are inclined at an angle α2 with respect to the surface of the original P passing between the transmitting sensor chip 53 and the receiving sensor chip 56, adhesion of foreign matter such as paper dust to the first protective member 70 and the second protective member 73 can be suppressed.

[0114] Furthermore, since the transmitting sensor chip 53 and the receiving sensor chip 56 are inclined at an angle α1 with respect to the surface of the original P passing between the transmitting sensor chip 53 and the receiving sensor chip 56, multiple reflections of ultrasonic waves between the transmitting sensor chip 53 and the original P, or between the receiving sensor chip 56 and the original P, can be suppressed. In addition, since the angles α1 and α2 are different, multiple reflections of ultrasonic waves between the transmitting sensor chip 53 and the first protective member 70 can be suppressed, and multiple reflections of ultrasonic waves between the receiving sensor chip 56 and the second protective member 73 can be suppressed.

[0115] 5 to 7, the scanner 1 includes a transmission-side path forming member 36 which is a member that forms the reading transport path R2, which is a document transport path between the first roller pair 13 and the second roller pair 16, and which fixes the transmission board holder 60. A removable cover 37 is provided on the transmission-side path forming member 36, and when the cover 37 is attached, the transmission board holder 60 is covered by the cover 37, and when the cover 37 is removed, the separation roller 15 becomes replaceable and the transmission board holder 60 is exposed. In particular, the first protection member 70 is exposed. This allows easy access to the transmission board holder 60. As a result, for example, replacement and maintenance of the first protective member 70 becomes easy.

[0116] Furthermore, the transmitting board holder 60 has a fixing portion 60a that fixes the first protective member 70, the transmitting board 52 is fixed to the rear side of the fixing portion 60a, and the fixing portion 60a has a first wall portion 60b that is a wall portion facing the side of the fixed transmitting board 52 and covers at least a part of the transmitting board 52. As a result, when a foreign object tries to get around to the transmitting board 52 from the side of the fixing portion 60a, the first wall portion 60b can prevent this.

[0117] <Relationship between the configuration of the ultrasonic detection unit and other configurations of the scanner> Next, the relative positional relationship between the configuration of the ultrasonic detection unit 50 and other components of the scanner 1 will be described. First, the positional relationship between the ultrasonic detection unit 50 and the first roller pair 13 will be described with reference to Fig. 23. Fig. 23 shows the positional relationship between the ultrasonic detection unit 50 and the first roller pair 13 as viewed from upstream in the conveying direction Fp. In Fig. 23, the feed roller 14 and separation roller 15 that constitute the first roller pair 13 are indicated by two-dot chain lines. As shown in the figure, at least a part of the transmitting sensor chip 53 and at least a part of the receiving sensor chip 56 are inside a range Ua1 of the first roller pair 13 in the normal direction Da to the document surface S at the nip position of the first roller pair 13. This makes it possible to reduce the device dimensions in the normal direction Da.

[0118] In this embodiment, the entire transmitting sensor chip 53 and the entire receiving sensor chip 56 are inside the range Ua1 in the normal direction Da, but a part of the transmitting sensor chip 53 and a part of the receiving sensor chip 56 may be inside the range Ua1 in the normal direction Da. Alternatively, a part of the transmitting sensor chip 53 and the entire receiving sensor chip 56 may be inside the range Ua1 in the normal direction Da. Alternatively, the entire transmitting sensor chip 53 and a part of the receiving sensor chip 56 may be inside the range Ua1 in the normal direction Da.

[0119] In addition, reference symbol 14a denotes the rotation shaft of the feed roller 14, and reference symbol 15a denotes the rotation shaft of the separation roller 15. In this embodiment, the distance between the axial center of the rotation shaft 14a and the axial center of the rotation shaft 15a, i.e., the axial distance dk1, is 16.6 mm, which is shorter than the distance between the transmitting sensor chip 53 and the receiving sensor chip 56, i.e., the sensor distance of 24.9 mm. This makes it possible to reduce the area occupied by the first roller pair 13 in the direction along the axial distance dk1, and thus to suppress the device dimensions. In this embodiment, the shaft diameter of the rotating shaft 14a is 6.0 mm, and the shaft diameter of the rotating shaft 15a is 3.0 to 6.0 mm, for example 3.9 mm or 5.18 mm, both of which are larger than the thickness of the transmitting sensor chip 53 or the receiving sensor chip 56, 0.578 mm.

[0120] Next, the positional relationship between the ultrasonic detection unit 50, the second roller pair 16, and the third roller pair 20 will be described with reference to Fig. 24. Fig. 24 shows the positional relationship between the ultrasonic detection unit 50, the second roller pair 16, and the third roller pair 20 as viewed from upstream in the conveying direction Fp. 24, the second lower roller 17 and the second upper roller 18 constituting the second roller pair 16 are indicated by two-dot chain lines. Note that the contour of the third lower roller 21 constituting the third roller pair 20 overlaps with the second lower roller 17, and the contour of the third upper roller 22 constituting the third roller pair 20 overlaps with the second upper roller 18. As will be described in more detail later, the second upper roller 18 and the third upper roller 22 are both arranged to move forward and backward relative to the opposing rollers, and Figure 24 shows the state in which the second upper roller 18 and the third upper roller 22 are both in contact with the opposing rollers.

[0121] As shown in the figure, at least a part of the transmitting sensor chip 53 and at least a part of the receiving sensor chip 56 are inside the range Ua2 of the second roller pair 16 or the third roller pair 20 in the normal direction Da to the document surface S at the nip position of the second roller pair 16 or the third roller pair 20. This makes it possible to reduce the device dimensions in the normal direction Da to the document surface S at the nip position of the second roller pair 16 or the third roller pair 20.

[0122] In this embodiment, the entire transmitting sensor chip 53 and the entire receiving sensor chip 56 are inside the range Ua2 in the normal direction Da, but a part of the transmitting sensor chip 53 and a part of the receiving sensor chip 56 may be inside the range Ua2 in the normal direction Da. Alternatively, a part of the transmitting sensor chip 53 and the entire receiving sensor chip 56 may be inside the range Ua2 in the normal direction Da. Alternatively, the entire transmitting sensor chip 53 and a part of the receiving sensor chip 56 may be inside the range Ua2 in the normal direction Da. The relationship between the dimensions of the rotation shafts of the second lower roller 17, the second upper roller 18, the third lower roller 21, and the third upper roller 22 and the dimensions of the transmitting sensor chip 53 and the receiving sensor chip 56 will be explained later.

[0123] In this embodiment, a portion of the transmitting board 52 and the entire receiving board 55 are inside the range Ua1 in the normal direction Da. However, the entire transmitting board 52 and the entire receiving board 55 may be inside the range Ua1 in the normal direction Da. Alternatively, a portion of the transmitting board 52 and a portion of the receiving board 55 may be inside the range Ua1 in the normal direction Da. Alternatively, the entire transmitting board 52 and a portion of the receiving board 55 may be inside the range Ua1 in the normal direction Da.

[0124] Furthermore, the distance between the center of the rotation axis of the second lower roller 17 and the center of the rotation axis of the second upper roller 18, or the distance between the center of the rotation axis of the third lower roller 21 and the center of the rotation axis of the third upper roller 22, i.e., the inter-axis distance dk2, is 15.4 mm, which is shorter than the distance between the transmitting sensor chip 53 and the receiving sensor chip 56, i.e., the inter-sensor distance of 24.9 mm. This makes it possible to reduce the area occupied by the second roller pair 16 or the third roller pair 20 in the direction along the center distance dk2, thereby making it possible to suppress the dimensions of the device.

[0125] Next, the transmitting board 52 and the receiving board 55 are inclined with respect to the normal direction Da to the document surface S that passes between the transmitting sensor chip 53 and the receiving sensor chip 56, and the transmitting surface 53a of the transmitting sensor chip 53 is along the surface of the transmitting board 52, and the receiving surface 56a of the receiving sensor chip 56 is along the surface of the receiving board 55. At least a part of the transmitting substrate 52 and at least a part of the receiving substrate 55 are within the range of the second roller pair 16 or the third roller pair 20 in the normal direction Da to the document surface S at the nip position of the second roller pair 16 or the third roller pair 20. This makes it possible to reduce the device dimensions in the normal direction Da.

[0126] In this embodiment, the entire transmitting board 52 and a part of the receiving board 55 are inside the range Ua2 in the normal direction Da, but a part of the transmitting board 52 and a part of the receiving board 55 may be inside the range Ua2 in the normal direction Da. Alternatively, a part of the transmitting board 52 and the entire receiving board 55 may be inside the range Ua2 in the normal direction Da. Alternatively, the entire transmitting board 52 and the entire receiving board 55 may be inside the range Ua2 in the normal direction Da.

[0127] In this embodiment, the entire transmitting sensor chip 53 and the entire receiving sensor chip 56 are inside the range Ua2 in the normal direction Da. However, a part of the transmitting sensor chip 53 and a part of the receiving sensor chip 56 may be inside the range Ua2 in the normal direction Da. Alternatively, a part of the transmitting sensor chip 53 and the entire receiving sensor chip 56 may be inside the range Ua2 in the normal direction Da. Alternatively, the entire transmitting sensor chip 53 and a part of the receiving sensor chip 56 may be inside the range Ua2 in the normal direction Da.

[0128] Next, the configuration of the second roller pair 16 will be further described with reference to FIG. In this embodiment, two sets of second roller pairs 16 are provided along the X-axis direction, i.e., the document width direction, and the two sets of second roller pairs 16 are provided at positions symmetrical to each other in the document width direction about the center position CL of the document P. The reference symbol 17a denotes a rotation shaft of the second lower roller 17. Symbol 18a1 is a rotating shaft located between the two second upper rollers 18, and symbol 18a2 is a rotating shaft located on both sides of the two second upper rollers 18, and the shaft diameter of rotating shaft 18a1 is smaller than the shaft diameter of rotating shaft 18a2. Rotation shaft 18a2 located in the +X direction is connected to first universal joint 31A. Second universal joint 31B is further provided in the +X direction relative to first universal joint 31A, and first universal joint 31A and second universal joint 31B are connected by rotation shaft 18a3.

[0129] The second upper roller 18 moves forward and backward relative to the second lower roller 17 and power is transmitted to the second upper roller 18, so that the second upper roller 18 can be driven while moving forward and backward relative to the second lower roller 17 by the first universal joint 31A and the second universal joint 31B. 25 shows a state in which the second upper roller 18 is in contact with the second lower roller 17, and the upper view in Fig. 25 shows a state in which the second upper roller 18 is farthest from the second lower roller 17. The symbol M1 indicates the range in which the second upper roller 18 moves.

[0130] As shown in the figure, in this embodiment, the entire receiving sensor chip 56 and the entire receiving substrate 55 are inside the range M1 in the normal direction Da, so that the device dimensions in the normal direction Da can be reduced. In this embodiment, the entire receiving sensor chip 56 and the entire receiving substrate 55 are inside the range M1 in the normal direction Da, but a part of the receiving sensor chip 56 and a part of the receiving substrate 55 may be inside the range M1 in the normal direction Da. Alternatively, the entire receiving sensor chip 56 and a part of the receiving substrate 55 may be inside the range M1 in the normal direction Da. The relationship between the third roller pair 20, the receiving sensor chip 56, and the receiving substrate 55 is the same as the relationship between the second roller pair 16, the receiving sensor chip 56, and the receiving substrate 55 described above.

[0131] In this embodiment, the diameter of the rotating shaft 17a is 6.0 mm. The diameter of the rotating shaft 18a1 is 4.0 mm, the diameter of the rotating shaft 18a2 is 5.0 mm, and the diameter of the rotating shaft 18a3 is 4.5 mm, all of which are larger than the thickness of the transmitting sensor chip 53 or the receiving sensor chip 56.

[0132] As described above, the path length between the first roller pair 13 and the second roller pair 16, i.e., the path length of the downstream feeding path R1, is shorter than the path length between the second roller pair 16 and the third roller pair 20, i.e., the path length of the reading transport path R2. This makes it possible to reduce the path length between the first roller pair 13 and the second roller pair 16, and therefore the dimensions of the device.

[0133] 13 to 15, the transmitting board 52 and the receiving board 55 have a long side E2 and a short side E1, and are arranged so that the short side E1 is aligned with the conveying direction Fp. This allows the first roller pair 13 and the second roller pair 16 to be closer to each other in the conveying direction Fp, which contributes to the miniaturization of the device.

[0134] Further, the length of the short side E1 of the transmitting board 52 and the receiving board 55 is shorter than the length of the glass plate 32e in the conveying direction Fp. Here, the configurations of the first reading unit 32 and the second reading unit 33 will be described with reference to Fig. 26. Note that the configurations of the first reading unit 32 and the second reading unit 33 are basically the same, and the configuration of the first reading unit 32 will be described below.

[0135] The first reading unit 32 includes a lower housing 32f and an upper housing 32g, and a sensor substrate 32a is provided on the lower housing 32f. A linear image sensor 32b, which is an example of a reading sensor, is provided on the sensor substrate 32a, and the image sensor 32b receives reflected light arriving from the document P via a lens 32c. Reference numeral 32d denotes a light source that illuminates the document P. A glass plate 32e is provided in the upper housing 32g. The glass plate 32e transmits light reflected by the original P to the lens 32c, and also has a function of coming into contact with the original P and guiding the original P downstream.

[0136] As described above, the length of the short side E1 of the transmitting board 52 and the receiving board 55 is shorter than the length of the glass plate 32e in the transport direction Fp. In this embodiment, the length of the short side E1 of the transmitting board 52 and the receiving board 55 is 8.6 mm, the length of the long side E2 is 26.8 mm, and the length of the glass plate 32e in the transport direction Fp is 12.6 mm. As a result, it is possible to reduce the length of the short side E1 of the transmitting board 52 and the receiving board 55 in the transport direction Fp. As a result, the first roller pair 13 and the second roller pair 16 can be brought even closer to each other in the transport direction Fp, which contributes to further miniaturization of the device.

[0137] In this embodiment, the thickness of the glass plate 32e is 1.1 mm, which is greater than the thickness of the transmitting sensor chip 53 or the receiving sensor chip 56, which is 0.578 mm.

[0138] Next, Fig. 27 shows the positional relationship between the transmitting substrate 52 and the transmitting sensor chip 53, and the sensor substrate 32a and image sensor 32b when the transmitting substrate 52 and the transmitting sensor chip 53 are viewed from upstream in the transport direction Fp. In Fig. 27, the sensor substrate 32a and the image sensor 32b are indicated by two-dot chain lines. As shown in the figure, the transmitting sensor chip 53 is located on the +Da side of the image sensor 32b in the normal direction Da, that is, on the second reading unit 33 side. This makes it possible to suppress the amount by which the transmitting sensor chip 53 protrudes from the first reading unit 32 to the -Da side, that is, downward, in the normal direction Da, and thus makes it possible to suppress the device dimensions in the normal direction Da.

[0139] Next, Fig. 28 shows the positional relationship between the transmitting board 52 and the transmitting sensor chip 53 when viewed from upstream in the transport direction Fp, and the second reading unit 33. In Fig. 28, the outer shape of the second reading unit 33 and the image sensor 32B provided in the second reading unit 33 are indicated by two-dot chain lines. The second reading unit 33 advances and retreats relative to the first reading unit 32, with the lower diagram in Fig. 28 showing the state where it is furthest away from the first reading unit 32, and the upper diagram in Fig. 28 showing the state where it is furthest advanced relative to the first reading unit 32. The range indicated by the symbol M2 indicates the region where the second reading unit 33 is displaced. As shown in the figure, at least a part of the receiving sensor chip 56 is inside the range M2 in the normal direction Da. This makes it possible to suppress the device dimensions in the normal direction Da. Similarly, at least a portion of the receiving substrate 55 is inside the range M2 in the normal direction Da. This makes it possible to reduce the device dimensions in the normal direction Da.

[0140] In this embodiment, the entire receiving sensor chip 56 and the entire receiving substrate 55 are inside the range M2 in the normal direction Da, but a part of the receiving sensor chip 56 and a part of the receiving substrate 55 may be inside the range M2 in the normal direction Da. Alternatively, the entire receiving sensor chip 56 and a part of the receiving substrate 55 may be inside the range M2 in the normal direction Da.

[0141] Next, FIG. 29 shows the areas occupied by the first roller pair 13, the second roller pair 16, the transport motor 47, the transmitting sensor chip 53, the transmitting board 52, the receiving sensor chip 56, and the receiving board 55 when viewed from the X-axis direction. As shown in the figure, at least a part of the transmitting substrate 52 and at least a part of the transmitting sensor chip 53 are located within the area occupied by the transport motor 47. This makes it possible to prevent the device from becoming large. In this embodiment, a portion of the transmitting board 52 and the entire transmitting sensor chip 53 are located within the occupied area of ​​the transport motor 47, but the entire transmitting board 52 and the entire transmitting sensor chip 53 may be located within the occupied area of ​​the transport motor 47, or alternatively, the entire transmitting board 52 and the entire transmitting sensor chip 53 may be located within the occupied area of ​​the transport motor 47.

[0142] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these modifications are also included in the scope of the present invention. For example, in the above embodiment, the medium conveying device 100 is applied to a scanner 1, which is an example of an image reading device, but this is not limited to this, and the medium conveying device 100 may also be applied to a recording device that records on a medium, or a post-processing device that performs post-processing on a medium, such as stapling or punching. [Explanation of symbols]

[0143] 1...scanner, 2...device body, 3...first unit, 4...second unit, 4a...top surface, 5...third unit, 6...main body support section, 6a...standing wall section, 6b...elastic deformation section, 6c...main body rotation shaft, 6e...first contact section, 6f...second contact section, 7...operation section, 7a, 7b, 7c...operation buttons, 7d...display section, 8a...lock release section, 9...original support, 10...upper opening / closing section, 11...original support section, 13...first roller pair, 14...feed roller, 15...separation roller, 15a...rotation shaft, 15b...torque limiter, 16...second roller pair, 17...second lower roller, 18...second upper roller, 20...third roller pair, 21...third lower roller, 21a...rotating shaft, 22...third upper roller, 22a...rotating shaft, 24...fourth roller pair, 25...fourth driving roller, 26...fourth driven roller, 28...fifth roller pair, 29...fifth driving roller, 30...fifth driven roller, 31A...first universal joint, 31B...second universal joint, 32...first reading unit, 32a...sensor board, 32b...image sensor, 32c...lens, 32d...light source, 32e...glass plate, 32f...lower housing, 32g...upper housing, 33...second reading unit, 34...pressure spring, 35...flap, 3 6...transmission side path forming member, 37...cover, 37a...opening, 38...roller holding member, 39...reception side path forming member, 39a...opening, 39b...positioning portion, 47...conveyor motor, 48...main board, 50...ultrasonic detection portion, 50A...transmission unit, 50B...reception unit, 52...transmission board, 52a...opening, 52b...recess, 52c...connector, 52d...board surface, 53...transmission sensor chip, 53a...transmission surface, 54...transmission board fixing screw, 55...reception board, 55c...connector, 56...reception sensor chip, 56a...reception surface, 57...reception board fixing screw, 58...transmission circuit path, 59...receiving circuit, 60...transmitting circuit board holder, 60a...fixing portion, 60b...first wall portion, 60c...protective member positioning portion, 60d...board positioning portion, 60e...screw hole, 60f...first opening, 60g...screw hole, 60h...second wall portion, 60j...screw fixing portion, 60k...screw fixing portion, 60m...projection portion, 61...transmitting side holder fixing screw, 62...receiving circuit board holder, 62a...fixing portion, 62c...protective member positioning portion, 62d...board positioning portion, 62e...hole portion, 62f...second opening, 62j...fixed portion, 62k...positioned portion, 63...receiving side holder fixing screw, 65...first enclosure member,65a...opening, 67...second enclosing member, 70...first protective member, 70a...wire, 70b...opening, 71...first holding member, 71a...recess, 71b...opening, 73...second protective member, 74...second holding member, 76...transmitting cable, 77...receiving cable, 80...control unit, 81...calculating unit, 82...transport control unit, 83...reading control unit, 84...multiple feed determination unit, 85...storage unit, 86...interface unit, 87...external Parts equipment, 100...medium conveying device, 210...element substrate, 211...substrate main body, 211A...opening, 211B...partition wall, 212...vibration plate, 212A...vibration section, 213...base substrate, 220...piezoelectric element, 221...first electrode, 222...piezoelectric film, 223...second electrode, Tr...ultrasonic transducer, R0...upstream feed path, R1...downstream feed path, R2...reading conveying path, R3...U-turn discharge path,

Claims

1. A first roller pair that transports the medium in a transport direction; a second roller pair disposed downstream of the first roller pair in the conveying direction; an ultrasonic detection unit disposed between the first roller pair and the second roller pair in the transport direction; A medium conveying device comprising: The ultrasonic detection unit includes: a transmitting sensor tip that emits ultrasonic waves along a first axis toward a first surface of the transported medium; a receiving sensor chip that is disposed on the first axis at a position where the medium is sandwiched between the transmitting sensor chip and the receiving sensor chip, and receives ultrasonic waves; a transmitting substrate on which the transmitting sensor chip is provided, the transmitting substrate having a substrate surface on which the transmitting sensor chip is placed; a receiving substrate on which the receiving sensor chip is provided, the receiving substrate having a substrate surface on which the receiving sensor chip is mounted; having the first axis is inclined with respect to a plane of the medium passing between the transmitting sensor chip and the receiving sensor chip; The thickness of the transmitting sensor chip is smaller than the thickness of the transmitting substrate, The thickness of the receiving sensor chip is smaller than the thickness of the receiving substrate, at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are within the range of the second roller pair in a normal direction to a surface of the medium at a nip position of the second roller pair; A medium transport device comprising:

2. 2. The medium transport device according to claim 1, At least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are Within the range of the first roller pair in a normal direction to the surface of the medium at the nip position of the first roller pair. A medium transport device comprising:

3. 2. The medium transport device according to claim 1, a third roller pair is provided downstream of the second roller pair in the conveying direction; At least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are Within the range of the third roller pair in a normal direction to the surface of the medium at the nip position of the third roller pair. A medium transport device comprising:

4. 2. The medium transport device according to claim 1, a distance between the axes of the two rollers constituting the second roller pair is shorter than a distance between the transmitting sensor chip and the receiving sensor chip on the first axis; A medium transport device comprising:

5. 2. The medium transport device according to claim 1, a third roller pair is provided downstream of the second roller pair in the conveying direction; a distance between the axes of the two rollers constituting the third roller pair is shorter than a distance between the transmitting sensor chip and the receiving sensor chip on the first axis; A medium transport device comprising:

6. 2. The medium transport device according to claim 1, a distance between the axes of the two rollers constituting the first roller pair is shorter than a distance between the transmitting sensor chip and the receiving sensor chip on the first axis; A medium transport device comprising:

7. 2. The medium transport device according to claim 1, the transmitting substrate and the receiving substrate are inclined with respect to a normal direction to a surface of the medium passing between the transmitting sensor chip and the receiving sensor chip, a transmitting surface of the transmitting sensor chip aligned with a surface of the transmitting substrate; a receiving surface of the receiving sensor chip aligned with a surface of the receiving substrate; At least a portion of the transmitting substrate and at least a portion of the receiving substrate are within the range of the second roller pair in a normal direction to a surface of the medium at a nip position of the second roller pair. A medium transport device comprising:

8. 2. The medium transport device according to claim 1, a third roller pair is provided downstream of the second roller pair in the conveying direction; a path length between the first roller pair and the second roller pair is shorter than a path length between the second roller pair and the third roller pair; A medium transport device comprising:

9. 2. The medium transport device according to claim 1, a transmitting board holder for holding the transmitting board; a receiving substrate holder for holding the receiving substrate; a transmission-side path forming member that forms a medium transport path between the first roller pair and the second roller pair and that fixes the transmission board holder; a receiving-side path forming member that forms a medium transport path between the first roller pair and the second roller pair and that fixes the receiving substrate holder; Equipped with A medium transport device comprising:

10. 10. The medium transport device according to claim 9, the transmitting substrate holder includes a first protective member provided on the first axis and positioned between the transmitting sensor chip and a medium; the receiving substrate holder includes a second protective member disposed on the first axis and positioned between the receiving sensor chip and a medium; A medium transport device comprising:

11. The medium transport device according to any one of claims 1 to 10; a reading unit located downstream of the second roller pair in the transport direction and configured to read an image on the medium; An image reading device comprising:

12. 12. The image reading apparatus according to claim 11, the transmitting board and the receiving board each have a long side and a short side, and are arranged such that the short side is aligned with the transport direction; the reading unit has a glass plate that contacts the medium and guides the medium downstream; a length of the short side of the transmitting substrate and a length of the short side of the receiving substrate are both shorter than a length of the glass plate in the conveying direction; 1. An image reading apparatus comprising:

13. 12. The image reading apparatus according to claim 11, The reading unit includes a first reading unit that reads the first surface of the medium, and a second reading unit that reads a second surface opposite to the first surface, The first reading unit has a reading sensor, the transmitting sensor chip is located closer to the second reading unit than the reading sensor in a normal direction to a surface of the medium facing the first reading unit; 1. An image reading apparatus comprising:

14. 12. The image reading apparatus according to claim 11, The reading unit includes a first reading unit that reads the first surface of the medium and a second reading unit that reads a second surface of the medium, At least a portion of the receiving sensor chip is within the range of the second reading unit in a normal direction to a surface of the medium facing the second reading unit.

1. An image reading apparatus comprising:

Images