Medium conveying device and image reading device

Abstract

The invention relates to a medium conveying apparatus and an image reading apparatus. In the prior art, there is a room for improvement in the viewpoint of researching the structure and configuration of an ultrasonic sensor to realize miniaturization of a device. 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. The reception substrate is provided with an amplifier that amplifies a reception signal of the ultrasonic wave received by the sensor chip, and a shield member that covers at least a portion of the amplifier. A height of the reception sensor chip with respect to the reception substrate is lower than a height of the shield member with respect to the reception substrate.

Description

Technical Field

[0001] The present invention relates to a medium conveying device for conveying a medium and an image reading device including the medium conveying device. Background Art

[0002] Conventionally, as disclosed in Patent Document 1, a technique for detecting overlapping feeding of media using an ultrasonic sensor has been used.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-25242

[0004] The use of ultrasonic sensors tends to increase the size of the device.

[0005] In the prior art, there is still room for improvement in terms of studying the structure and arrangement of ultrasonic sensors to achieve miniaturization of the devices. Summary of the Invention

[0006] The medium conveying device of the present invention for solving the above-mentioned problems is characterized by comprising: a first roller pair for conveying a medium in a conveying direction; a second roller pair arranged downstream of the first roller pair in the conveying direction; and an ultrasonic detection unit arranged between the first roller pair and the second roller pair in the conveying direction, the ultrasonic detection unit comprising: a transmitting sensor chip for emitting ultrasonic waves along a first axis toward a first surface of the conveyed medium; a receiving sensor chip arranged at a position on the first axis with the transmitting sensor chip sandwiching the medium, for receiving the ultrasonic waves; a transmitting substrate on which the transmitting sensor chip is provided and on which the transmitting sensor chip is mounted; a receiving substrate on which the receiving sensor chip is provided and on which the receiving sensor chip is mounted; an amplifier provided on the receiving substrate for amplifying a reception signal of the ultrasonic waves received by the receiving sensor chip; and a shielding member provided on the receiving substrate and covering at least a portion of the amplifier, the height of the receiving sensor chip relative to the receiving substrate being lower than the height of the shielding member relative to the receiving substrate.

[0007] Furthermore, the image reading device of the present invention is characterized in that it includes: the medium transport device; and a reading unit located downstream of the second roller pair in the transport direction and configured to read an image on the medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a perspective view of the scanner from the front.

[0009] Figure 2 This is a diagram showing the document transport path of the scanner as viewed from the width direction.

[0010] Figure 3 This is a block diagram showing a control system of a scanner.

[0011] Figure 4 This is a perspective view of a state where the second unit is opened relative to the first unit.

[0012] Figure 5 This is a top view of the first unit.

[0013] Figure 6 This is a perspective view of a state where the cover provided on the first unit is attached.

[0014] Figure 7 This is a perspective view of a state where a cover provided on the first unit is removed.

[0015] Figure 8 This is a perspective view of the first unit as viewed from the back side.

[0016] Figure 9 It is a perspective view showing the fixed state of the sending substrate holder.

[0017] Figure 10 This is a top view of the second unit.

[0018] Figure 11 It is a perspective view showing the fixed state of the receiving substrate holder.

[0019] Figure 12 It is a perspective view showing the positional relationship among the first roller pair, the second roller pair, the third roller pair, and the ultrasonic detection unit.

[0020] Figure 13 This is a perspective view of the ultrasonic detection unit.

[0021] Figure 14 This is a perspective view of the ultrasonic detection unit.

[0022] Figure 15 This is a perspective view of the transmission substrate.

[0023] Figure 16 It is a side view of the transmitting substrate.

[0024] Figure 17 This is a perspective view of the transmission substrate holder.

[0025] Figure 18 This is a perspective view of the transmission substrate holder.

[0026] Figure 19 It is a three-dimensional diagram of the protective component.

[0027] Figure 20 It is an enlarged top view of the protective component.

[0028] Figure 21It is a cross-sectional view showing the structure of a transmitting sensor chip.

[0029] Figure 22 It is a cross-sectional view showing the structure of the ultrasonic detection unit.

[0030] Figure 23 It is a diagram showing the positional relationship between the ultrasonic detection unit and the first roller pair.

[0031] Figure 24 It is a diagram showing the positional relationship between the ultrasonic detection unit and the second roller pair or the third roller pair.

[0032] Figure 25 It is a figure which shows the structure of a 2nd roller pair.

[0033] Figure 26 It is a cross-sectional perspective view showing the structure of the first reading unit.

[0034] Figure 27 This figure shows the positional relationship between the sensor substrate of the first reading unit, the transmitting sensor chip, and the transmitting substrate.

[0035] Figure 28 This is a diagram showing the positional relationship among the second reading unit, the receiving sensor chip, and the receiving substrate.

[0036] Figure 29 This figure shows the occupied areas of the first roller pair, the second roller pair, the conveying motor, the transmitting sensor chip, the transmitting substrate, the receiving sensor chip, and the receiving substrate.

[0037] Figure 30 is a side view of the receiving substrate.

[0038] Figure 31 is a side view of the receiving substrate.

[0039] Figure 32 is a side view of the receiving substrate.

[0040] [Explanation of Reference Numerals]

[0041] 1: Scanner; 2: Device body; 3: First unit; 4: Second unit; 4a: Upper surface; 5: Third unit; 6: Main body support portion; 6a: Vertical wall portion; 6b: Elastic deformation portion; 6c: Main body rotation axis; 6e: First abutment portion; 6f: Second abutment portion; 7: Operation portion; 7a, 7b, 7c: Operation buttons; 7d: Display portion; 8a: Lock release portion; 9: Document support member; 10: Upper opening and closing portion; 11: Document support portion; 13: First roller pair; 14: Feed roller; 15: Separation roller; 15a: Rotation axis; 15b: Torque limiter; 16: Second roller pair; 17: Second lower roller; 18: Second upper roller; 20: Third roller pair; 21: Third lower roller; 21a: Rotation axis; 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 section; 32a: Sensor substrate; 32b: Image sensor; 32c: Lens; 32d: Light source; 32e: Glass plate; 32f: Lower frame; 32g: Upper frame; 33: Second reading section; 34: Pressing spring; 35: Hinge plate; 36: Sending-side path forming member; 37: Cover; 37a: Opening; 38: Roller holding member; 39: Receiving-side path forming member; 39a: Opening; 39b: Positioning section; 47: Conveying motor; 48: Main substrate; 50: Ultrasonic detection unit; 51: Voltage application unit; 50A: Transmitting unit; 50B: Receiving unit; 52: Transmitting substrate; 52a: Opening; 52b: Recess; 52c: Connector; 52d: Substrate surface; 53: Transmitting sensor chip; 53a: Transmitting surface; 54: Transmitting substrate fixing screw; 55: Receiving substrate; 55c: Connector; 55d: First substrate surface; 55e: Second substrate surface; 56: Receiving sensor chip; 56a: Receiving surface; 57: Receiving substrate fixing screw; 58: Transmitting circuit; 59: Receiving circuit; 60: Transmitting substrate bracket; 60a: Fixing portion; 60b: First wall portion; 60c: Protective member positioning portion; 60d: Substrate positioning portion; 60e: Screw hole ; 60f: first opening; 60g: threaded hole; 60h: second wall portion; 60j: screw fixing portion; 60k: screw fixing portion; 60m: protrusion; 61: sending-side bracket fixing screw; 62: receiving substrate bracket; 62a: fixing portion; 62c: protective member positioning portion; 62d: substrate positioning portion; 62e: hole portion; 62f: second opening; 62j: fixed portion; 62k: positioned portion; 63: receiving-side bracket fixing screw; 65: first surrounding member; 65a: opening; 67: second surrounding member; 70: first protective member; 70a: wire rod; 70b: opening; 71: first holding member; 71a: recess; 71b: opening; 73: second protective member; 74: second holding member;76: Transmitter cable; 77: Receiving cable; 80: Control unit; 81: Calculation unit; 82: Conveyance control unit; 83: Reading control unit; 84: Overlapping feed detection unit; 85: Storage unit; 86: Interface unit; 87: External device; 91: Shield member; 100: Medium conveying device; 210: Element substrate; 211: Substrate main body; 211A: Opening; 211B: Partition wall; 212: Vibration plate; 212A: Vibration unit; 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 and conveying path; R3: U-turn discharge path. DETAILED DESCRIPTION

[0042] Hereinafter, the present invention will be briefly described.

[0043] A medium conveying device according to a first embodiment is characterized by comprising: a first roller pair for conveying a medium in a conveying direction; a second roller pair arranged downstream of the first roller pair in the conveying direction; and an ultrasonic detection unit arranged between the first roller pair and the second roller pair in the conveying direction, the ultrasonic detection unit comprising: a transmitting sensor chip for emitting ultrasonic waves along a first axis toward a first surface of the conveyed medium; a receiving sensor chip arranged at a position on the first axis with the transmitting sensor chip sandwiching the medium, for receiving the ultrasonic waves; a transmitting substrate on which the transmitting sensor chip is provided and on which the transmitting sensor chip is mounted; a receiving substrate on which the receiving sensor chip is provided and on which the receiving sensor chip is mounted; an amplifier provided on the receiving substrate for amplifying a reception signal of the ultrasonic waves received by the receiving sensor chip; and a shielding member provided on the receiving substrate and covering at least a portion of the amplifier, the height of the receiving sensor chip relative to the receiving substrate being lower than the height of the shielding member relative to the receiving substrate.

[0044] According to this aspect, since the height of the receiving sensor chip relative to the receiving substrate is lower than the height of the shield member relative to the receiving substrate, the device size can be reduced in a configuration in which the receiving substrate includes the ultrasonic receiving unit and the shield member.

[0045] The second method is a method subordinate to the first method, and is characterized in that the first axis is inclined relative 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 located within the range of the second roller pair in the normal direction of the surface of the medium at the clamping position relative to the second roller pair.

[0046] According to this method, since at least a portion of the transmitting sensor chip and at least a portion of the receiving sensor chip are located within the range of the second roller pair in the normal direction of the surface of the medium at the clamping position relative to the second roller pair, the device size in the normal direction of the surface of the medium at the clamping position relative to the second roller pair can be suppressed.

[0047] A third aspect is an aspect dependent on the first aspect, and is characterized in that, in the receiving substrate, the amplifier and the shield member are provided on a surface opposite to a surface on which the receiving sensor chip is provided.

[0048] According to this embodiment, since the amplifier and the shielding member are provided on the surface of the receiving substrate opposite to the surface on which the receiving sensor chip is provided, both the one surface and the other surface of the receiving substrate can be effectively utilized, making it easier to reduce the size of the receiving substrate. This can thereby reduce the size of the device.

[0049] In addition, this aspect is not limited to the first aspect described above, and may also be subordinate to the second aspect described above.

[0050] A fourth aspect is a aspect dependent on the first aspect, characterized in that a connector is provided on the receiving substrate on a surface opposite to a surface facing the receiving sensor chip, and the amplifier and the shielding member are arranged on the surface of the receiving substrate on which the connector is provided.

[0051] According to this aspect, since the amplifier and the shield member are arranged in the space generated by the arrangement of the connector, the size of the device can be suppressed.

[0052] In addition, this aspect is not limited to the first aspect described above, and may also be subordinate to the second aspect described above.

[0053] A fifth aspect is an aspect dependent on the first aspect, characterized in that, in the receiving substrate, the amplifier is arranged on a surface where the receiving sensor chip is provided, and the shield member covers not only the amplifier but also the receiving sensor chip.

[0054] According to this aspect, since the shield member covers not only the amplifier but also the receiving sensor chip, by using the same shield member to cover the amplifier and the receiving sensor chip, it is possible to suppress the size of the device and the cost increase.

[0055] In addition, this aspect is not limited to the first aspect described above, and may also be subordinate to the second aspect described above.

[0056] The sixth method is a method subordinate to the first method, and is characterized in that at least a portion of the receiving substrate and at least a portion of the shielding member are located within the range of the first roller pair in the normal direction of the surface of the medium at the clamping position relative to the first roller pair, or are located within the range of the second roller pair in the normal direction of the surface of the medium at the clamping position relative to the second roller pair.

[0057] According to this method, since at least a portion of the receiving substrate and at least a portion of the shielding member are located within the range of the first roller pair in the normal direction of the surface of the medium at the clamping position relative to the first roller pair, or are located within the range of the second roller pair in the normal direction of the surface of the medium at the clamping position relative to the second roller pair, the size of the device in the normal direction of the surface of the medium at the clamping position relative to the first roller pair or the second roller pair can be suppressed.

[0058] In addition, this aspect is not limited to the first aspect, and may be any one of the second to fifth aspects.

[0059] The seventh method is a method subordinate to the first method, and is characterized in that the first axis is inclined relative to the surface of the medium passing between the transmitting sensor chip and the receiving sensor chip, and when calibrating the ultrasonic detection unit, ultrasonic waves are received by the receiving sensor chip in a state where a bias voltage is applied to the receiving sensor chip, and the received signal is amplified by the amplifier.

[0060] According to this aspect, when a piezoelectric element is used in the receiving sensor chip, the polarization direction of the piezoelectric element is less likely to deviate, an efficient amplitude can be obtained, and an appropriate reception signal can be output.

[0061] In addition, this aspect is not limited to the first aspect, and may be subordinate to any one of the second to sixth aspects.

[0062] The eighth method is a method subordinate to the seventh method, and is characterized in that the first axis is inclined relative to the surface of the medium passing between the transmitting sensor chip and the receiving sensor chip, and when the overlapping conveyance of the medium is detected by the ultrasonic detection unit, the ultrasonic wave is received by the receiving sensor chip in a state where a bias voltage is applied to the receiving sensor chip, and the received signal is amplified by the amplifier.

[0063] According to this aspect, when a piezoelectric element is used in the receiving sensor chip, the polarization direction of the piezoelectric element is less likely to deviate, an efficient amplitude can be obtained, and an appropriate reception signal can be output.

[0064] An image reading device according to a ninth aspect comprises: the medium conveying device according to any one of the first to eighth aspects; and a reading unit located downstream of the second roller pair in the conveying direction and configured to read an image on the medium.

[0065] According to this aspect, in the image reading device, the effects of any one of the first to eighth aspects can be obtained.

[0066] Hereinafter, the present invention will be described in detail.

[0067] Hereinafter, as an example of an image reading device, a scanner 1 is used that can read at least one of a first surface S1 and an opposite second surface S2 of an original document P, which is an example of a medium. The scanner 1 is a so-called sheet-fed scanner that reads the original document P while moving it relative to a first reading unit 32 and a second reading unit 33, which will be described later.

[0068] In this specification, the document P includes not only sheet-shaped documents but also card-shaped documents and booklet-shaped documents.

[0069] Furthermore, from the perspective of conveying a document P as an example of a medium, the scanner 1 can be understood as a medium conveying device 100. In this case, the scanner 1 includes the medium conveying device 100, and a first reading unit 32 and a second reading unit 33 described below.

[0070] In the XYZ coordinate system shown in each figure, the X-axis direction is the width direction of the device and also 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.

[0071] In this embodiment, the +Y direction is set as the direction from the back of the device to the front, and the -Y direction is set as the direction from the front of the device to the back. In addition, when viewed from the front of the device, the left direction is set as the +X direction, and the right direction is set as the -X direction.

[0072] In the following description, the direction in which the document P is conveyed may be referred to as “downstream”, and the opposite direction may be referred to as “upstream”.

[0073] <Scanner Overview>

[0074] exist Figure 1 In FIG, the scanner 1 includes an apparatus body 2 and a body support portion 6 that supports the apparatus body 2. The body support portion 6 is placed on a placement surface GS of the apparatus. As an example, the placement surface GS is a surface parallel to a horizontal plane.

[0075] The device main body 2 is configured to include a first unit 3 , a second unit 4 , and a third unit 5 .

[0076] The second unit 4 and the third unit 5 are rotatable relative to the first unit 3 about a rotation axis (not shown) parallel to the X-axis direction. The second unit 4 and the third unit 5 are integrally rotatable relative to the first unit 3 about the rotation axis. Figure 1 Reference numeral 8a in the figure denotes a lock release portion. The user can release the lock of the second unit 4 and the third unit 5 relative to the first unit 3 by sliding the lock release portion 8a in the -X direction. In addition, by rotating the second unit 4 and the third unit 5 relative to the first unit 3, a part of the document conveying path can be exposed (see FIG. Figure 4 In particular, by opening the second unit 4 relative to the first unit 3 , the upstream feed path R0 , the downstream feed path R1 , and the reading transport path R2 described later can be exposed.

[0077] In addition, the third unit 5 can rotate relative to the first unit 3 and the second unit 4 about a rotation axis parallel to the X-axis direction (not shown). By rotating the third unit 5 relative to the second unit 4, the downstream U-turn discharge path R3 (see Figure 2 ) is exposed from the reading conveying path R2 described later. That is, the U-turn discharge path R3 is formed between the third unit 5 and the second unit 4.

[0078] The third unit 5 is held on the second unit 4 by a snap-fit ​​structure (not shown). The user can release the third unit 5 from the second unit 4 by applying an external force to the third unit 5 , thereby opening the third unit 5 .

[0079] The device body 2 can rotate relative to the body support portion 6 about the body rotation axis 6c (see Figure 2 ) is the center of rotation. In this embodiment, the device body 2 can maintain two postures by rotating. Figure 2The apparatus body 2 is in one of two positions, the normal reading position. The apparatus body 2 can be rotated from the normal reading position so that the reading and conveying path R2 becomes nearly horizontal, thereby obtaining a booklet reading position (not shown).

[0080] exist Figure 1 In the embodiment, an operation unit 7 composed of a plurality of operation buttons is provided on the front of the device. In this embodiment, the plurality of operation buttons are composed of operation buttons 7a, 7b, and 7c, and user operations are accepted through these buttons.

[0081] <Scanner's document feeding path>

[0082] Next, refer to Figure 2 The document transport path in the scanner 1 will be described. Figure 2 In FIG. 1 , a thick dotted line indicates a conveyance path along which the document P is conveyed.

[0083] Reference symbol R0 denotes a conveying path upstream of the first roller pair 13 , and will hereinafter be referred to as an upstream feed path R0 .

[0084] Reference symbol R1 is a conveying path between the first roller pair 13 and the second roller pair 16 , hereinafter referred to as a downstream feed path R1 .

[0085] Reference numeral R2 denotes a conveyance path between the second roller pair 16 and the third roller pair 20, hereinafter referred to as a reading conveyance path R2. The reading conveyance path R2 is a conveyance path facing a first reading unit 32 and a second reading unit 33 described later.

[0086] The first unit 3 constitutes the lower side of the upstream feeding path R0 , the downstream feeding path R1 , and the reading conveying path R2 , and the second unit 4 constitutes the upper side of the upstream feeding path R0 , the downstream feeding path R1 , and the reading conveying path R2 .

[0087] In addition, reference numeral R3 denotes a conveying path that is turned 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 .

[0088] The normal reading posture of the device body 2 ( Figure 2 ) is the position in which the reading conveyance path R2 is connected to the U-turn discharge path R3 via the hinge plate 35. Furthermore, in the booklet reading position (not shown) of the apparatus body 2, the hinge plate 35 assumes the position indicated by the two-dot chain line, and the reading conveyance path R2 is disconnected from the U-turn discharge path R3, so that the document P is discharged from the reading conveyance path R2 in an obliquely downward direction including a +Y component and a -Z component.

[0089] The normal reading posture is suitable for reading sheet-like documents P, that is, documents P that are relatively rigid and easily bendable. The booklet reading posture is suitable for reading documents P that are relatively rigid and difficult to bend, such as plastic cards and booklets.

[0090] The document transport path will be further described below. The fed document P is supported in an inclined position by the document support 11 and the document support member 9. When multiple documents P are supported by the document support 11, the topmost document P is fed downstream by the feed roller 14. The document support 11 is formed within the upper opening and closing section 10. The upper opening and closing section 10 is rotatable about a rotation axis (not shown), opening and closing the feed port.

[0091] The document support 9 can be placed in a state housed in the upper opening and closing portion 10 and can be deployed from the upper opening and closing portion 10 . Figure 1 Indicates the state in which the upper opening and closing portion 10 is closed. Figure 2 The upper opening and closing section 10 is opened and the document support 9 is further extended. The upper opening and closing section 10 and the document support 9 constitute the first unit 3.

[0092] Furthermore, the scanner 1 adopts a so-called center feed method, and the center position of the document P in the X-axis direction, that is, the width direction, remains constant regardless of the size of the document P.

[0093] The feed roller 14 and the separation roller 15 constitute a first roller pair 13 .

[0094] The feed roller 14 is provided in the second unit 4. The feed roller 14 is driven by a conveying motor 47 (see Figure 3 ) obtains power and rotates. In the first unit 3, a separation roller 15 is provided at a position opposite to the feed roller 14. The separation roller 15 is secured by a torque limiter 15b (see Figure 6 ) imparts a rotational torque to suppress overlapping conveyance of the original P.

[0095] In addition, in this embodiment, the feed roller 14 is arranged on the upper side relative to the original P placed on the original support portion 11, and feeding starts from the top original P, but it can also be arranged on the lower side relative to the original P placed on the original support portion 11, and feeding starts from the bottom original P.

[0096] The ultrasonic detection unit 50 is provided in the downstream feed path R1 downstream of the first roller pair 13. The ultrasonic detection unit 50 includes a transmitting unit 50A and a receiving unit 50B which are arranged to face each other across the downstream feed path R1. Figure 3 ) can detect overlapping feeding of the originals P based on the signal sent from the receiving unit 50B.

[0097] In addition, Figure 2The position, size, and shape of the transmitting unit 50A and the receiving unit 50B are conceptually shown in FIG. Figure 4 The following drawings will be used for further explanation.

[0098] In addition, in this embodiment, the sending unit 50A is arranged on the lower side of the downstream feed path R1, and the receiving unit 50B is arranged on the upper side of the downstream feed path R1, but it is not limited to this. The receiving unit 50B may also be arranged on the lower side of the downstream feed path R1 and the sending unit 50A may be arranged on the upper side of the downstream feed path R1.

[0099] A second roller pair 16 is provided downstream of the feed roller 14 and the separation roller 15. The second roller pair 16 is comprised 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 configured to be able to advance and retract relative to the second lower roller 17 and is pressed toward the second lower roller 17 by a pressing member (not shown), such as a coil spring. Consequently, the second upper roller 18 advances and retracts relative to the second lower roller 17 in accordance with the thickness of the document P being conveyed.

[0100] The second lower roller 17 and the second upper roller 18 are both driven by the conveying motor 47 (refer to Figure 3 ) gains momentum and rotates.

[0101] When the second unit 4 is closed relative to the first unit 3, the second lower roller 17 is in contact with the second upper roller 18. When the second unit 4 is opened relative to the first unit 3, the second upper roller 18 is separated from the second lower roller 17.

[0102] 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.

[0103] The first reading unit 32 reads the first surface S1, the lower surface of the document P supported by the document support 11, while the second reading unit 33 reads the second surface S2, the upper surface of the document P supported by the document support 11. The second reading unit 33 is configured to be able to advance and retreat relative to the first reading unit 32 and is pressed toward the first reading unit 32 by a pressing spring 34, an example of a pressing member. Thus, the second reading unit 33 advances and retreats relative to the first reading unit 32 according to the thickness of the document P being fed.

[0104] In this embodiment, the first reading unit 32 and the second reading unit 33 are formed of a contact image sensor module (CISM).

[0105] A third roller pair 20 is provided downstream of the first reading section 32 and the second reading section 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 retract relative to the third lower roller 21 and is pressed toward the third lower roller 21 by a pressing member (not shown), such as a coil spring.

[0106] The third lower roller 21 and the third upper roller 22 are both driven by a conveying motor 47 (refer to Figure 3 ) gains momentum and rotates.

[0107] When the second unit 4 is closed relative to the first unit 3, the third lower roller 21 is in contact with the third upper roller 22. When the second unit 4 is opened relative to the first unit 3, the third upper roller 22 is separated from the third lower roller 21.

[0108] A hinge plate 35 is provided downstream of the third roller pair 20. The hinge plate 35 switches the document conveyance path as described above by rotating.

[0109] In addition, in this embodiment, the hinge plate 35 is configured to rotate in conjunction with the switching of the posture of the device body 2. As a structure for rotating the hinge plate 35 in conjunction with the switching of the posture of the device body 2, in this embodiment, a structure is used in which the hinge plate 35 is mechanically rotated in conjunction with the posture of the device body 2 by a linkage mechanism (not shown), such as a cam mechanism. However, the hinge plate 35 may also be rotated by a solenoid (not shown). In this case, the control unit 80 (see Figure 3 ) Based on the detection information of the posture detection sensor (not shown), the solenoid is driven to rotate the hinge plate 35.

[0110] A fourth roller pair 24 and a fifth roller pair 28 are provided in the U-turn discharge path R3 .

[0111] 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 able to advance and retreat relative to the fourth driving roller 25 and is pressed toward the fourth driving roller 25 by a pressing member (not shown), such as a coil spring. Thus, the fourth driven roller 26 advances and retreats relative to the fourth driving roller 25 according to the thickness of the document P being conveyed. The fourth driving roller 25 is driven by a conveying motor 47 (see Figure 3 The fourth driven roller 26 is a roller that rotates drivenly.

[0112] 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 able to advance and retreat relative to the fifth driving roller 29 and is pressed toward the fifth driving roller 29 by a pressing member (not shown), such as a coil spring. Thus, the fifth driven roller 30 advances and retreats relative to the fifth driving roller 29 according to the thickness of the document P being conveyed. The fifth driving roller 29 is driven by a conveying motor 47 (see Figure 3 The fifth driven roller 30 is a roller that rotates drivenly.

[0113] When the third unit 5 is closed relative to the second unit 4, the fourth drive roller 25 contacts the fourth driven roller 26, and the fifth drive roller 29 also contacts the fifth driven roller 30. When the third unit 5 is opened relative to the second unit 4, the fourth drive roller 25 separates from the fourth driven roller 26, and the fifth drive roller 29 also separates from the fifth driven roller 30.

[0114] 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 in an inclined posture by the upper surface 4 a of the second unit 4 .

[0115] also, Figure 2 The direction indicated by the arrow Da1 represents the normal direction relative to the first surface S1 and the second surface S2 opposite thereto of the document P at the document clamping position of the first roller pair 13. Since the first surface S1 and the second surface S2 opposite thereto of the document P are generally parallel, they are collectively referred to as the document surface S below unless otherwise distinguished.

[0116] In addition, an arrow Da2 indicates the direction of a normal line with respect to the document surface S of the document P passing between the transmission unit 50A and the reception unit 50B of the ultrasonic detection section 50 .

[0117] In addition, an arrow Da3 indicates the normal direction with respect to the document surface S at the document nipping position in the second roller pair 16 .

[0118] In addition, an arrow Da4 indicates the direction of a normal line with respect to the document surface S of the document P passing between the first reading section 32 and the second reading section 33 .

[0119] In addition, an arrow Da5 indicates the normal direction with respect to the document surface S at the document nipping position in the third roller pair 20 .

[0120] In this embodiment, since the differences among the normal directions Da1, Da2, Da3, Da4, and Da5 are small, as an example, the difference between the maximum angle and the minimum angle is within 5°, the normal direction Da will be referred to as the normal direction without distinguishing between them.

[0121] in addition, Figure 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 conveyed. Hereinafter, this direction is referred to as the conveyance direction Fp.

[0122] In addition, Figure 4 In the future, the X-Fp-Da coordinate system will be used depending on the situation.

[0123] <Scanner Control System>

[0124] Next, refer to Figure 3 The control system of the scanner 1 will be described.

[0125] 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 nonvolatile memory and a volatile memory.

[0126] The first reading unit 32, the second reading unit 33, the conveying motor 47, and the ultrasonic detection unit 50 are connected to the control unit 80, and the control unit 80 controls them. The conveying motor 47 is the driving 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.

[0127] The control unit 80 is connected to the interface unit 86 , receives various data and signals input from an external device 87 such as a personal computer, and outputs read data obtained by the scanner 1 to the external device 87 .

[0128] Various data and various programs for controlling the scanner 1 are recorded in the storage unit 85 .

[0129] The calculation unit 81 reads and executes various programs stored in the storage unit 85 to function as a conveyance control unit 82 , a reading control unit 83 , an overlapped feed detection unit 84 , and the like.

[0130] The conveyance control unit 82 controls the conveyance motor 47 to rotate the plurality of rollers, thereby feeding, conveying, and discharging the document P.

[0131] The reading control unit 83 controls the first reading unit 32 and the second reading unit 33 to read an image of the document P while the document P is being conveyed.

[0132] The double-feeding detector 84 is a state detection unit that detects the state of the document P. In the present embodiment, the double-feeding detector 84 detects double-feeding of the document P based on a reception signal input from a reception circuit 59 (described later).

[0133] Specifically, when the voltage value of the received signal is smaller than a predetermined threshold, it is determined that the document P is being multi-fed.

[0134] <Basic Structure of Ultrasonic Detection Unit>

[0135] Next, the basic structure of the ultrasonic detection unit 50 will be described.

[0136] exist Figure 22 In FIG, the ultrasonic detection unit 50 includes a pair of ultrasonic elements. One of the pair of ultrasonic elements is a transmitting sensor chip 53 that transmits ultrasonic waves. The other of the pair of ultrasonic elements is a receiving sensor chip 56 that receives ultrasonic waves.

[0137] The transmitting sensor chip 53 and the receiving sensor chip 56 are opposed to each other on a sensor center axis Lx, which is an example of a first axis, and are arranged with the document P conveyed in the downstream feed path R1 interposed therebetween.

[0138] In the ultrasonic detection unit 50, ultrasonic waves are emitted from the transmitting sensor chip 53 toward the first side S1 of the fed document P. The ultrasonic waves emitted by the transmitting sensor chip 53 are input to the document P, and the ultrasonic waves transmitted through the document P are received by the receiving sensor chip 56. When the receiving sensor chip 56 receives the ultrasonic waves, it outputs a reception signal corresponding to the sound pressure of the received ultrasonic waves. Based on the signal strength of this reception signal, it determines whether the documents P are being fed in a double-feed manner.

[0139] 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 serves as the direction of ultrasonic transmission and reception. 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.

[0140] Furthermore, the sensor center axis Lx is inclined with respect to the document surface S of the document P at an angle β.

[0141] Here, when the sensor center axis Lx is aligned with the normal to the document surface S, that is, when the angle β = 90°, there is a risk that the ultrasonic waves transmitted from the transmitting sensor chip 53 will be reflected multiple times between the document P and the transmitting sensor chip 53. Furthermore, there is a risk that the ultrasonic waves that have passed through the document P will be reflected multiple times between the receiving sensor chip 56 and the document P. In this case, in addition to the ultrasonic waves transmitted from the transmitting sensor chip 53 through the document P and received by the receiving sensor chip 56, the ultrasonic waves that have been reflected multiple times between the document P and the transmitting sensor chip 53 and between the receiving sensor chip 56 and the document P will also be received by the receiving sensor chip 56, making accurate overlapped feed detection impossible.

[0142] In contrast, by tilting the sensor central axis Lx relative 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 double-feeding detection.

[0143] Furthermore, the angle β can be set to 60° to 80°, and is set to 70° in this embodiment.

[0144] Furthermore, when the area of ​​the transmitting surface 53a of the transmitting sensor chip 53 is small, the ultrasonic beam diameter becomes smaller. In this case, if the distance between the transmitting sensor chip 53 and the receiving sensor chip 56, that is, the distance along the sensor central axis Lx, is short, the sound pressure drop of the ultrasonic wave increases when the transmitting sensor chip 53 deviates from the sensor central axis Lx due to mounting errors. Similarly, when the area of ​​the receiving surface 56a of the receiving sensor chip 56 is small, the sound pressure drop increases when the chip deviates from the sensor central axis Lx. Therefore, it is preferable to maintain a certain distance between the transmitting sensor chip 53 and the receiving sensor chip 56. However, if the distance between the transmitting sensor chip 53 and the receiving sensor chip 56 is too long, this will also lead to a decrease in sound pressure.

[0145] In this embodiment, considering the above viewpoint, the distance between the transmitting sensor chip 53 and the receiving sensor chip 56 along the sensor center axis Lx, that is, the inter-sensor distance, is set to a range of 15.0 mm to 30.0 mm, and is set to 24.9 mm as an example.

[0146] <Sensor Chip Structure>

[0147] The structure of the ultrasonic detection unit 50 will be further described.

[0148] like Figure 3As shown, a transmitting circuit 58 for controlling the transmitting sensor chip 53 is provided on the transmitting substrate 52 , and a receiving circuit 59 for controlling the receiving sensor chip 56 is provided on the receiving substrate 55 .

[0149] Here, refer to Figure 21 The structure of the transmitting sensor chip 53 will be described.

[0150] The transmitting sensor chip 53 is configured to include a base substrate 213 , an element substrate 210 , and a piezoelectric element 220 .

[0151] The element substrate 210 includes a substrate body 211 and a vibration plate 212 provided on one side of the substrate body 211. In the following description, the substrate thickness direction of the element substrate 210 is referred to as the G direction. The G direction is the direction in which ultrasonic waves are transmitted and is parallel to the sensor central axis Lx.

[0152] The substrate body 211 is a substrate provided on the vibration plate 212 and is formed of a semiconductor substrate such as Si. The substrate body 211 has an opening 211A extending through the substrate body 211 in the G direction.

[0153] The vibration plate 212 is supported by the base substrate 213. The vibration plate 212 and the base substrate 213 are bonded and fixed. A space for arranging the piezoelectric element 220 is provided between the base substrate 213 and the vibration plate 212.

[0154] In addition, the vibration plate 212 may be fixed to the base substrate 213 in a stacked state.

[0155] The vibration plate 212 is formed of a laminate of SiO2, SiO2, and GrO2, and is provided on the -G side of the substrate body 211. This vibration plate 212 closes the -G side of the opening 211A. The portion of the vibration plate 212 that overlaps the opening 211A when viewed from the G direction constitutes the vibration portion 212A.

[0156] The piezoelectric element 220 is provided on the vibration plate 212 at a position overlapping each vibration portion 212A when viewed from the direction G. The piezoelectric element 220 is formed by sequentially stacking a first electrode 221 , a piezoelectric film 222 , and a second electrode 223 on the vibration plate 212 .

[0157] Here, one ultrasonic transducer Tr is formed by one vibration part 212A and the piezoelectric element 220 provided on the vibration part 212A. Although not shown in the figure, in this embodiment, the transmitting sensor chip 53 is formed by arranging such ultrasonic transducers Tr in a two-dimensional array structure. The transmitting circuit 58 (see Figure 3 ) is electrically connected to each ultrasonic transducer Tr of the transmitting sensor chip 53 to generate a driving signal for driving each ultrasonic transducer Tr.

[0158] The transmitting sensor chip 53 applies a pulse voltage of a predetermined frequency between the first electrode 221 and the second electrode 223 of each ultrasonic transducer Tr, causing the piezoelectric film 222 to expand and contract. This causes the vibrating portion 212A to vibrate at a frequency corresponding to, for example, the opening width of the opening 211A, and ultrasonic waves are transmitted from the vibrating portion 212A toward the +G side along the sensor central axis Lx. Specifically, the +G side surface of the element substrate 210 serves as the ultrasonic transmission surface 53a of the transmitting sensor chip 53.

[0159] The base substrate 213 of the transmitting sensor chip 53 is bonded to the transmitting substrate 52 with a non-conductive adhesive via a resist. The transmitting substrate 52 is also provided with at least one of a chip tilt prevention pad (not shown) to prevent 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 suppression portion (not shown) to prevent overflow of the non-conductive adhesive. Furthermore, the transmitting sensor chip 53 is bonded to the transmitting substrate 52 with silver paste at a location separate from the chip tilt prevention pad (not shown), which is not used for electrical conduction.

[0160] The structure of the receiving sensor chip 56 is omitted from illustration, but it has the same structure as the transmitting sensor chip 53 described above. In this case, the +G side surface of the element substrate 210 serves as the ultrasonic wave receiving surface 56a of the receiving sensor chip 56. When ultrasonic waves reach the ultrasonic transducer Tr, the vibration plate 212 vibrates according to the sound pressure of the ultrasonic waves. The piezoelectric film 222 is deformed by the vibration of the vibration plate 212, generating a potential difference between the first electrode 221 and the second electrode 223. As a result, a reception signal corresponding to the sound pressure of the received ultrasonic waves is output from the first electrode 221 of the ultrasonic transducer Tr. Thus, the ultrasonic waves are detected.

[0161] The receiving circuit 59 ( Figure 3 ), a conventional circuit for processing the received signal input by receiving ultrasonic waves can be used. For example, receiving circuit 59 can be composed of a bandpass filter, an amplifier, a sample-and-hold circuit, a comparator, etc. (not shown). Therefore, considering the function of the amplifier, receiving circuit 59 can also be called an amplifier.

[0162] The ultrasonic detection unit 50 according to this embodiment includes a voltage application unit 51 for applying a bias voltage to the receiving sensor chip 56. The voltage application unit 51 may be mounted on a dedicated substrate, on the receiving substrate 55, or may be part of the control unit 80.

[0163] During calibration, the ultrasonic detection unit 50 receives ultrasonic waves via the receiving sensor chip 56 while a bias voltage is applied to the receiving sensor chip 56, and the received signal is amplified by the receiving circuit 59. Calibration involves transmitting ultrasonic waves from the transmitting sensor chip 53 in the absence of a document P, and adjusting the output of the transmitted ultrasonic waves based on the sound pressure of the ultrasonic waves received by the receiving sensor chip 56.

[0164] When the receiving sensor chip 56 uses the piezoelectric element 220 , applying a bias voltage to the receiving sensor chip 56 reduces the polarization direction of the piezoelectric element 220 from deviating, and an efficient amplitude can be obtained, thereby outputting an appropriate reception signal.

[0165] Similarly, when detecting overlapped feeding of documents P, the ultrasonic detection unit 50 receives ultrasonic waves via the receiving sensor chip 56 while a bias voltage is applied to the receiving sensor chip 56, and amplifies the received signal via the receiving circuit 59. Consequently, even when detecting overlapped feeding of documents P, the polarization direction of the piezoelectric element 220 is less likely to deviate, an efficient amplitude can be obtained, and an appropriate received signal can be output.

[0166] <Structure of Transmitting Sensor Unit and Receiving Sensor Unit>

[0167] Next, the configurations of the transmission unit 50A and the reception unit 50B will be described.

[0168] Figure 4 This shows a state where 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 inner side of the first unit 3 and the inner side of the second unit 4 are exposed.

[0169] A transmission-side path forming member 36 is provided inside the first unit 3 , and the transmission-side path forming member 36 is exposed when the second unit 4 is opened relative to the first unit 3 .

[0170] Furthermore, a receiving-side path forming member 39 is provided inside the second unit 4 , and the receiving-side path forming member 39 is exposed when the second unit 4 is opened relative to the first unit 3 .

[0171] The sending-side path forming member 36 and the receiving-side path forming member 39 form a part of the upstream feeding path R0 , the downstream feeding path R1 , and the reading conveying path R2 .

[0172] like Figure 5 As shown, a cover 37 is provided on the transmission side path forming member 36. The cover 37 is provided to obtain Figure 5 、 Figure 6 Assembled as shown and Figure 7The cover 37 is provided in a detachable state with respect to the transmission-side path forming member 36. The cover 37 is provided so as to be attachable to the transmission-side path forming member 36 by a snap-fit ​​structure (not shown).

[0173] A circular opening 37a is formed in the cover 37, and the sensor central axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the opening 37a. A portion of a first protective member 70 described later is exposed inside the opening 37a.

[0174] A transmitting unit 50A is provided on the inner side of the cover 37. When the cover 37 is removed, Figure 7 As shown, the transmitting unit 50A is exposed. Figure 6 As shown in FIG, in the state where the cover 37 is mounted, a portion of the transmission unit 50A is also exposed, but when the cover 37 is opened, the transmission unit 50A is exposed more. Figure 6 In the illustrated assembled state of the cover 37 , a portion of a first wall portion 60 b of a transmission substrate holder 60 , which will be described later, is exposed.

[0175] 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 the separation roller 15 can be replaced together with the roller holding member 38 .

[0176] In addition, Figure 6 In the figure, reference numeral 15 a denotes a rotation axis of the separation roller 15 , and reference numeral 15 b denotes a torque limiter for applying a separation torque to the separation roller 15 .

[0177] In addition, Figure 5 , reference numeral 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-axial distance, and reference numeral 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-axial distance.

[0178] In this embodiment, the inter-axial distance Ba1 is shorter than the inter-axial distance Ba2. In other words, the path length of the downstream feed path R1 is shorter than the path length of the reading transport path R2.

[0179] In addition, in the present embodiment, the inter-axial distance Ba1 is 29.1 mm, and the inter-axial distance Ba2 is 34.0 mm.

[0180] Then, if Figure 8 As shown, a conveying motor 47 and a main substrate 48 are provided on the -Da side of the transmission side path forming member 36. The conveying motor 47 is provided on the back side of the transmission side path forming member 36 at the end in the -X direction.

[0181] The main substrate 48 constitutes the control unit 80. Figure 9 As shown, a transmission unit 50A is provided between the main substrate 48 and the transmission-side path forming member 36 .

[0182] The structure of the transmission unit 50A will be described in detail later. The transmission unit 50A is based on a transmission substrate holder 60 , and the transmission substrate holder 60 is fixed to the transmission-side path forming member 36 by screws 61 , 61 .

[0183] Then, if Figure 10 As shown, a circular opening 39a is formed in the receiving-side path forming member 39, and the sensor center axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the opening 39a. A portion of the second protective member 73 described later is exposed inside the opening 39a.

[0184] In addition, Figure 10 , reference numeral Bb1 is the distance between the rotation axis center of the feed roller 14 and the rotation axis center of the second upper roller 18, i.e., the inter-axis distance, and reference numeral Bb2 is the distance between the rotation axis center of the second upper roller 18 and the rotation axis center of the third upper roller 22, i.e., the inter-axis distance.

[0185] In this embodiment, the inter-axis distance Bb1 is shorter than the inter-axis distance Bb2. In other words, the path length of the downstream feed path R1 is shorter than the path length of the reading transport path R2.

[0186] In addition, in the present embodiment, the inter-axial distance Bb1 is 30.0 mm, and the inter-axial distance Bb2 is 34.0 mm.

[0187] like Figure 11 As shown, a receiving unit 50B is provided on the +Da direction side of the receiving-side path forming member 39 .

[0188] The structure of the receiving unit 50B will be described in detail later. The receiving unit 50B is based on a receiving substrate holder 62. The fixed portion 62j, which constitutes the receiving substrate holder 62, is fixed to the receiving-side path-forming member 39 via a receiving-side holder fixing screw 63. Reference numeral 39b denotes a positioning portion provided on the receiving-side path-forming member 39. By fitting a hole 62e in a positioned portion 62k provided on the receiving substrate holder 62 with the positioning portion 39b, the positioned portion 62k is positioned relative to the receiving-side path-forming member 39.

[0189] Thereby, the receiving substrate holder 62 is positioned and fixed relative to the receiving-side path forming member 39 .

[0190] Next, refer to Figure 12 The configurations of the transmission unit 50A and the reception unit 50B will be further described in the following drawings.

[0191] like Figure 12 As shown, the ultrasonic detection unit 50 is disposed in the space between the first roller pair 13 and the second roller pair 16. Arranged in this order along the conveyance direction Fp are the separation roller 15 constituting the first roller pair 13, the transmitter 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. Furthermore, arranged in this order along the conveyance direction Fp are the feed roller 14 constituting the first roller pair 13, the receiver 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.

[0192] like Figure 13 、 Figure 14 As shown, the transmission unit 50A is configured such that a transmission substrate 52 and a first protective member 70 are provided on a transmission substrate holder 60 .

[0193] Similarly, the receiving unit 50B is configured such that the receiving substrate 55 and the second protective member 73 are placed on the receiving substrate holder 62 .

[0194] like Figure 17 、 Figure 18 As shown, the transmitting substrate holder 60 has screw holes 60e at the screw fixing portions 60j and 60k, respectively. Figure 9 The screw 61 described above is passed through the threaded hole 60e. Between the screw fixing portion 60j and the screw fixing portion 60k, the fixing portion 60a is formed so as to be located closer to the +Da direction than the screw fixing portions 60j and 60j. The fixing portion 60a is a portion for fixing the first protective member 70, and a first opening 60f is formed in the center (see FIG. Figure 17 、 Figure 18 、 Figure 22 ), the first opening 60f is formed so that the sensor center axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the first opening 60f.

[0195] Protective member positioning portions 60c, 60c are formed on the surface of the fixing portion 60a. Figure 19 As shown, the first protective member 70 is held by the first holding member 71. The first holding member 71 has recesses 71a, 71a formed therein. The recesses 71a, 71a engage with the protective member positioning portions 60c, 60c, thereby positioning the first holding member 71, ie, the first protective member 70, relative to the fixing portion 60a.

[0196] like Figure 18 As shown, a cylindrical protrusion 60m is formed on the back side of the fixing portion 60a, and a threaded hole 60g is formed in the protrusion 60m. Figure 14 As shown, a substrate positioning portion 60d is formed on the back side of the fixing portion 60a.

[0197] like Figure 15As shown, an opening 52a and a recess 52b are formed in the transmitting substrate 52. The opening 52a is engaged with the protrusion 60m of the transmitting substrate holder 60, and the recess 52b is engaged with the substrate positioning portion 60d of the transmitting substrate holder 60, thereby positioning the transmitting substrate 52 relative to the transmitting substrate holder 60. Figure 14 As shown, by aligning the sending substrate fixing screw 54 with the threaded hole 60g ( Figure 18 ) are engaged, and the sending substrate 52 is fixed relative to the sending substrate bracket 60.

[0198] The transmitting substrate holder 60 is configured to position the transmitting surface 53a of the transmitting sensor chip 53 relative to the document surface S. Figure 22 As shown, the transmitting substrate 52 is held so as to be tilted at an angle α1. Thus, the transmitting surface 53a of the transmitting sensor chip 53 and the receiving surface 56a of the receiving sensor chip 56 are parallel, and the sensor central axis Lx is tilted at an angle β relative to the document surface S.

[0199] In addition, if Figure 13 、 Figure 14 、 Figure 17 、 Figure 18 As shown, a first wall portion 60b is formed upstream of the fixed portion 60a in the conveying direction Fp, and a second wall portion 60h is formed downstream of the fixed portion 60a in the conveying direction Fp.

[0200] like Figure 6 As shown, the first wall portion 60 b is located at a position visible from the outside when the cover 37 is closed, and serves to protect the transmission substrate 52 from foreign matter, liquid, and the like.

[0201] Although not shown in the figure, when the first wall portion 60b is viewed from upstream in the conveyance direction Fp, the first wall portion 60b is located at a position overlapping with a portion of the transmission substrate 52 and the entire transmission sensor chip 53. In other words, when the first wall portion 60b is viewed from upstream in the conveyance direction Fp, a portion of the transmission substrate 52 and the entire transmission sensor chip 53 are located at a position hidden by the first wall portion 60b.

[0202] Next, the receiving substrate holder 62 has a reference Figure 11 The fixed portion 62j and the positioned portion 62k are described. The fixing portion 62a is formed between the fixed portion 62j and the positioned portion 62k so as to be located in the -Da direction from the fixed portion 62j and the positioned portion 62k. The fixing portion 62a is a portion for fixing the second protective member 73. A second opening 62f is formed in the center (see FIG. Figure 22 ), the second opening 62f is formed so that the sensor center axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the second opening 62f.

[0203] like Figure 14 As shown, protective member positioning portions 62c, 62c are formed on the surface of the fixing portion 62a. The second protective member 73 is held by a second holding member 74, which has recessed portions 74a, 74a formed therein. By fitting these recessed portions 74a, 74a with the protective member positioning portions 62c, 62c, the second holding member 74, i.e., the second protective member 73, is positioned relative to the fixing portion 62a.

[0204] like Figure 13 As shown, a protruding substrate positioning portion 62d is formed on the back side of the fixing portion 62a. A recess 55b is formed on the receiving substrate 55. The recess 55b is engaged with the substrate positioning portion 62d. In addition, although not shown in the figure, the receiving substrate holder 62 is formed with a protrusion and a threaded hole similar to the protrusion 60m and the threaded hole 60g of the transmitting substrate holder 60. In addition, the receiving substrate 55 is formed with an opening 52a (see Figure 15 ) the same opening. Moreover, the opening is engaged with the protrusion of the receiving substrate holder 62, and the recess 55b of the receiving substrate 55 is engaged with the substrate positioning portion 62d of the receiving substrate holder 62, so that the receiving substrate 55 is positioned relative to the receiving substrate holder 62. Moreover, as Figure 13 As shown, the receiving substrate 55 is fixed to the receiving substrate holder 62 by fitting the receiving substrate fixing screws 57 into the threaded holes.

[0205] The receiving substrate holder 62 is arranged so that the receiving surface 56a of the receiving sensor chip 56 is opposite to the original surface S. Figure 22 As shown, the receiving substrate 55 is held tilted at an angle α1. Thus, the receiving surface 56a of the receiving sensor chip 56 is parallel to the transmitting surface 53a of the transmitting sensor chip 53, and the sensor center axis Lx is tilted at an angle β relative to the document surface S.

[0206] As described above, in this embodiment, the transmitting substrate 52 is fixed to the transmitting-side path-forming member 36, which forms the document conveyance path, via the transmitting substrate holder 60. Furthermore, the receiving substrate 55 is fixed to the receiving-side path-forming member 39, which forms the document conveyance path, via the receiving substrate holder 62. This stabilizes the distances between the document P and the transmitting sensor chip 53, and between the document P and the receiving sensor chip 56, and consequently, stabilizes the ultrasonic detection values.

[0207] Next, the structure of the transmission substrate 52 will be described.

[0208] like Figures 13 to 15As shown, the transmission substrate 52 is a rectangular substrate having short sides E1 and long sides E2. As described above, a recess 52b is formed on one short side E1. The transmission substrate 52 is arranged so that the short side E1 is along the conveying direction Fp.

[0209] The transmitting sensor chip 53 is fixed in a state of being placed on the substrate surface 52 d of the transmitting substrate 52 , and no member such as a pedestal exists between the transmitting sensor chip 53 and the substrate surface 52 d except for an adhesive.

[0210] A connector 52c is provided on the side of the transmission substrate 52 opposite to the substrate surface 52d, and a transmission side cable 76 (see Figure 13 、 Figure 14 ) is connected to the connector 52c.

[0211] Furthermore, a first enclosing member 65 is provided on the substrate surface 52d of the transmission substrate 52. In the present embodiment, the first enclosing member 65 is formed of a metal plate and is fixed to the transmission substrate 52 with an adhesive.

[0212] The first enclosing member 65 is formed with an opening 65a, and the opening 65a is formed so that the sensor center axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the opening 65a. Figure 16 As shown, the first enclosing member 65 is provided along the substrate surface 52d.

[0213] The transmitting substrate fixing screw 54 includes a head portion having a screwdriver fitting hole, a threaded portion having an external thread, and a tip portion at the tip of the external thread. The threaded portion is mounted on the same side of the transmitting sensor chip 53 as the substrate surface 52d of the transmitting substrate 52, specifically, in the threaded hole 60g (see Figure 18 、 Figure 22 ). In addition, the threaded portion may be mounted on a mounted portion, that is, a threaded hole, on the opposite side of the substrate surface 52 d of the transmitting substrate 52 from the transmitting sensor chip 53 .

[0214] When the transmission substrate 52 is fixed to the transmission substrate holder 60 , the tip 54 a of the transmission substrate fixing screw 54 is located closer to −Da in the normal direction Da than the most +Da-direction position 65 b of the first enclosure member 65 .

[0215] In addition, the direction along the sensor center axis Lx and from the transmitting unit 50A toward the receiving unit 50B is set as the +Lx direction, and the opposite direction is set as the -Lx direction. When the transmitting substrate 52 is fixed relative to the transmitting substrate bracket 60, the position of the top end 54a of the transmitting substrate fixing screw 54 is located closer to the +Lx direction than the first enclosing member 65.

[0216] Furthermore, the distance from the substrate surface 52 d of the transmission substrate 52 to the first enclosure member 65 is shorter than the length of the threaded portion of the transmission substrate fixing screw 54 .

[0217] exist Figure 16 t0 is the thickness including the transmission substrate 52 and the transmission sensor chip 53, t1 is the thickness of the transmission substrate 52, and t2 is the thickness of the transmission sensor chip 53. The thickness t2 of the transmission sensor chip 53 is thinner than the thickness of the transmission substrate 52.

[0218] As an example, the thickness of the transmission substrate 52 can be set to 0.8 mm to 1.2 mm, and can be particularly set to 1.0 mm. In addition, as an example, the thickness of the transmission sensor chip 53 can be set to 0.5 mm to 0.7 mm, and can be particularly set to 0.578 mm.

[0219] As an example, the distance from the substrate surface 52 d of the transmission substrate 52 to the first enclosing member 65 can be set to 1.2 mm to 1.6 mm, and particularly can be set to 1.4 mm.

[0220] Next, the structure of the receiving substrate 55 will be described.

[0221] In this embodiment, if Figure 13 、 Figure 14 As shown, the shape and size of the receiving substrate 55 are the same as those of the transmitting substrate 52.

[0222] That is, the receiving substrate 55 is a rectangular substrate having a short side E1 and a long side E2 , and is provided so that the short side E1 is along the conveyance direction Fp.

[0223] The receiving substrate 55 is provided with a connector 55 c , and the receiving-side cable 77 is connected to the connector 55 c .

[0224] Below, refer to Figure 30 The structure of the receiving substrate 55 is further described. Figure 30 to Figure 32 In the figure, for the convenience of illustration, the receiving substrate 55 is depicted horizontally.

[0225] The receiving sensor chip 56 is fixed in a state of being placed on the first substrate surface 55 d of the receiving substrate 55 , and no member such as a pedestal exists between the receiving sensor chip 56 and the first substrate surface 55 d except for an adhesive.

[0226] The first substrate surface 55d is a surface facing the transmitting sensor chip 53, and reference numeral 55e is a surface opposite to the first substrate surface 55d. The connector 55c is provided on the second substrate surface 55e.

[0227] The first substrate surface 55d is provided with a second enclosing member 67. In the present embodiment, the second enclosing member 67 is formed of a metal plate and is fixed to the receiving substrate 55 by an adhesive.

[0228] The second surrounding member 67 is formed with Figure 15 The transmission-side opening 65a is similar to the opening shown (not shown). The opening is formed so that the sensor center axis Lx of the ultrasonic detection unit 50 passes through the vicinity of the center of the opening. The second enclosing member 67 is provided along the first substrate surface 55d.

[0229] Next, a receiver circuit 59 is provided on the second substrate surface 55e. Receiver circuit 59 is in the form of a semiconductor chip, such as an ASIC (Application Specific Integrated Circuit). Receiver circuit 59 is mounted on and fixed to the second substrate surface 55e, with no other components, such as a pedestal, between the receiver circuit 59 and the second substrate surface 55e except for adhesive.

[0230] The receiving circuit 59 is covered by a shield member 91. In this embodiment, in order to obtain an electromagnetic shielding effect, the shield member 91 is formed of a metal plate material similar to the second enclosure member 67. The shield member 91 is fixed to the second substrate surface 55e by an adhesive.

[0231] exist Figure 30 In the figure, reference numeral t10 is the thickness of the receiving substrate 55, which is different from the thickness t1 of the transmitting substrate 52 (refer to Figure 16 Reference numeral t11 denotes the height of the receiving circuit 59 relative to the second substrate surface 55e. Reference numeral 12 denotes the height of the shielding member 91 relative to the second substrate surface 55e.

[0232] In addition, reference numeral t13 denotes the height of the receiving sensor chip 56 relative to the first substrate surface 55d, and reference numeral t14 denotes the height of the second enclosing member 67 relative to the first substrate surface 55d.

[0233] As an example, the thickness t10 can be set to 0.8 mm to 1.2 mm, and particularly can be set to 1.0 mm.

[0234] Furthermore, as an example, the height t11 ​​can be set to 0.9 mm to 1.3 mm, and can particularly be set to 1.1 mm.

[0235] Furthermore, as an example, the height t12 can be set to 1.8 mm to 2.2 mm, and can particularly be set to 2.0 mm.

[0236] Furthermore, as an example, the height t13 can be set to 0.5 mm to 0.7 mm, and can particularly be set to 0.578 mm.

[0237] Furthermore, as an example, the height t14 can be set to 1.2 mm to 1.6 mm, and can particularly be set to 1.4 mm.

[0238] exist Figure 22 In the figure, the receiving substrate fixing screw 57 includes a head portion having a screwdriver fitting hole, a threaded portion having external threads, and a tip portion at the tip of the external threads. The threaded portion is attached to the mounting portion on the same side as the receiving sensor chip 56 relative to the first substrate surface 55d of the receiving substrate 55, specifically, to the threaded hole 62g. Alternatively, the threaded portion can be attached to the mounting portion, i.e., the threaded hole, on the opposite side of the receiving sensor chip 56 relative to the first substrate surface 55d of the receiving substrate 55.

[0239] When the receiving substrate 55 is fixed to the receiving substrate holder 62 , the tip 57 a of the receiving substrate fixing screw 57 is located closer to the +Da direction than the position 67 b of the second enclosure member 67 closest to the −Da direction in the normal direction Da.

[0240] When the receiving substrate 55 is fixed to the receiving substrate holder 62 , the tip 57 a of the receiving substrate fixing screw 57 is positioned closer to the −Lx direction than the second enclosure member 67 in the axial direction of the sensor center axis Lx.

[0241] In addition, the distance from the first substrate surface 55 d of the receiving substrate 55 to the second enclosure member 67 is shorter than the length of the threaded portion of the receiving substrate fixing screw 57 .

[0242] As described above, the transmitting substrate 52 is provided with a first enclosing member 65, which surrounds the transmitting sensor chip 53 and is a plate-shaped member disposed along the transmitting substrate 52. Furthermore, the receiving substrate 55 is provided with a second enclosing member 67, which surrounds the receiving sensor chip 56 and is a plate-shaped member disposed along the receiving substrate 55. This protects the transmitting sensor chip 53 or the receiving sensor chip 56 from external forces. Furthermore, in this embodiment, the first enclosing member 65 and the second enclosing member 67 are formed of a metal material, thereby protecting the transmitting sensor chip 53 or the receiving sensor chip 56 from electromagnetic waves.

[0243] As described above, the receiving substrate 55 includes the receiving circuit 59 for amplifying the ultrasonic wave reception signal received by the receiving sensor chip 56 , and the shield member 91 provided on the receiving substrate 55 to cover at least a portion of the receiving circuit 59 .

[0244] Furthermore, the height t13 of the receiving sensor chip 56 relative to the receiving substrate 55 is lower than the height t12 of the shield member 91 relative to the receiving substrate 55. Thus, in a configuration in which the receiving substrate 55 includes the receiving sensor chip 56 and the shield member 91, the device size can be reduced.

[0245] In addition, in the present embodiment, the shield member 91 covers the entire receiving circuit 59 , but may cover a portion of the receiving circuit 59 .

[0246] In addition, in the present embodiment, a height t13 of the receiving sensor chip 56 relative to the receiving substrate 55 is lower than a height t11 ​​of the receiving circuit 59 relative to the receiving substrate 55 .

[0247] In addition, in the present embodiment, a height t14 of the second enclosing member 67 relative to the receiving substrate 55 is lower than a height t12 of the shield member 91 relative to the receiving substrate 55 .

[0248] In addition, in the present embodiment, a height t12 of the shield member 91 relative to the receiving substrate 55 is lower than a height t15 of the connector 55 c relative to the receiving substrate 55 .

[0249] Furthermore, in this embodiment, in the receiver substrate 55, the receiver circuit 59 and the shield member 91 are provided on the second substrate surface 55e opposite the first substrate surface 55d on which the receiver sensor chip 56 is provided. This allows for effective utilization of both the one and the other surfaces of the receiver substrate 55, facilitating miniaturization of the receiver substrate 55. This also allows for reduction in device size.

[0250] In this embodiment, the connector 55c is provided on the second substrate surface 55e of the receiver substrate 55. The receiver circuit 59 and the shield member 91 are arranged on the second substrate surface 55e of the receiver substrate 55 where the connector 55c is provided.

[0251] Thus, since the receiving circuit 59 and the shield member 91 are arranged in the space generated by the arrangement of the connector 55 c , the size of the device can be suppressed.

[0252] In addition, as other embodiments, Figure 31 As shown, the receiving circuit 59 may be arranged on the first substrate surface 55d on which the receiving sensor chip 56 is provided in the receiving substrate 55. In this case, the shielding member 91 may cover not only the receiving circuit 59 but also the receiving sensor chip 56. Thus, by using the same shielding member 91 to cover both the receiving circuit 59 and the receiving sensor chip 56, it is possible to reduce the size of the device while also suppressing cost increases.

[0253] In addition, when the receiving circuit 59 and the receiving sensor chip 56 are provided on the first substrate surface 55d, it is also possible to Figure 32 As shown, the receiving circuit 59 and the receiving sensor chip 56 are covered by different shielding members.

[0254] In addition, Figure 30 、 Figure 31 、 Figure 32 In any embodiment of the present invention, the receiving sensor chip 56 and the receiving circuit 59 are provided on one receiving substrate 55. However, the receiving sensor chip 56 and the receiving circuit 59 can also be provided on different substrates to form a receiving circuit 55 by arranging them. Figure 30 、 Figure 31 、 Figure 32 Same configuration structure.

[0255] <Structures of the First and Second Protective Members>

[0256] Next, the first protection member 70 and the second protection member 73 will be described in detail.

[0257] In addition, in this embodiment, the first protective member 70 and the second protective member 73 are made of the same material, and the second retaining member 74 that holds the second protective member 73 is also made of the same material as the first retaining member 71 that holds the first protective member 70. Therefore, the first protective member 70 and the first retaining member 71 are described below, and the description of the second protective member 73 and the second retaining member 74 is omitted.

[0258] In the present embodiment, the first protective member 70 is a filter configured in a mesh shape. Figure 20 This is an enlarged view showing a portion of the first protective member 70 .

[0259] exist Figure 20 In the embodiment, the first protective member 70 is a filter formed into a mesh shape by cross-arranging wires 70a. Figure 20 , an example is shown in which the wires 70a cross at 90°, but the present invention is not limited thereto, and the wires 70a may cross at an angle other than 90°.

[0260] As the material of the wire 70a, metal materials such as copper, iron, brass, and SUS, alloy materials, synthetic resins such as nylon and polyester fibers, etc. can be used. In this embodiment, polyester fibers are used as an example.

[0261] Furthermore, the wire diameter of the wire 70 a is preferably smaller than the wavelength of the ultrasonic wave. This can suppress the problem of diffuse reflection of the ultrasonic wave by the wire 70 a of the first protective member 70 .

[0262] In the first protective member 70, an opening 70b is formed between a pair of adjacent wires 70a. The opening 70b acts as a hole through which ultrasonic waves pass. To prevent foreign matter such as paper dust from adhering to and accumulating on the transmitting surface 53a of the transmitting sensor chip 53 and the receiving surface 56a of the receiving sensor chip 56, the width of the opening 70b, or opening width Wa, is preferably 1 mm or less.

[0263] However, in the present embodiment, the opening width Wa is set to 30 μm or less, and is set to 22 μm as an example, so that when the device is cleaned with a cleaning agent, the cleaning agent does not pass through the opening 70 b.

[0264] In addition, Figures 12 to 14 、 Figure 19 In the figure, the first protective member 70 or the second protective member 73 is shown as a mesh-shaped member for easy understanding, but the crossing angle and opening width Wa of the wires 70a are merely examples shown for ease of understanding.

[0265] As described above, since the first protective member 70 and the second protective member 73 are mesh-shaped members, ultrasonic waves can pass through the first protective member 70 and the second protective member 73 well.

[0266] Since the opening width Wa of the mesh-like member is 30 μm or less, when the device is cleaned with a cleaning agent, the cleaning agent can be prevented from passing through the first protective member 70 and adhering to the transmitting sensor chip 53, or from passing through the second protective member 73 and adhering to the receiving sensor chip 56. As a result, it is possible to prevent the intensity of the ultrasonic waves received by the receiving sensor chip 56 from being reduced, thereby preventing the problem of erroneous detection.

[0267] like Figure 19 As shown, the first protective member 70 is held by a first retaining member 71 having an opening 71b that exposes the first protective member 70. The first protective member 70 is held by the first retaining member 71 by being sandwiched between the two first retaining members 71. Double-sided tape (not shown) is used between the first protective member 70 and the first retaining member 71, thereby integrating the first protective member 70 with the first retaining member 71.

[0268] In addition, the relationship between the second protective member 73 and the second holding member 74 is the same as the relationship between the first protective member 70 and the first holding member 71 described above.

[0269] Next, the first protective member 70 is held by the sending substrate holder 60 so as to be opposite to the document surface S. Figure 22Similarly, the second protective member 73 is held by the receiving substrate holder 62 and tilted at an angle α2 relative to the document surface S. As a result, the angle between the first protective member 70 and the second protective member 73 is 0°, that is, the first protective member 70 and the second protective member 73 are parallel.

[0270] In the present embodiment, the angle α2 is set to be different from the angle α1. Specifically, the angle α2 is set to be smaller than the angle α1.

[0271] Specifically, when angle α2 and angle α1 are set to the same angle, that is, when the transmitting surface 53a is parallel to the first protective member 70, there is a risk that multiple reflections of ultrasonic waves will occur between the transmitting surface 53a and the first protective member 70, making accurate overlapped feed detection impossible. The same applies when the receiving surface 56a and the second protective member 73 are parallel.

[0272] However, as described above, since the angle α2 is set to be different from the angle α1, the aforementioned multiple reflections can be suppressed and overlapped feeding detection can be appropriately performed.

[0273] In addition, in this embodiment, as an example, the angle α1 is set to 20 degrees and the angle α2 is set to 15 degrees.

[0274] Furthermore, the distance between the transmitting surface 53a and the first protective member 70 is also a major factor contributing to multiple reflections of ultrasonic waves. Specifically, a shorter distance between the transmitting surface 53a and the first protective member 70 leads to multiple reflections of ultrasonic waves. Based on this consideration, 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 is set to 4.89 mm as an example.

[0275] The first protective member 70 described above is held by the transmitting substrate holder 60 along with the transmitting substrate 52. This prevents variations in the distance between the transmitting sensor chip 53 and the first protective member 70. Consequently, multiple reflections of ultrasonic waves between the transmitting sensor chip 53 and the first protective member 70 can be appropriately suppressed.

[0276] Similarly, the second protective member 73 is held together with the receiving substrate 55 by the receiving substrate holder 62, thereby suppressing variations 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.

[0277] Furthermore, the transmission substrate holder 60 has a first opening 60 f for passing ultrasonic waves on the sensor central axis Lx, and the first protection member 70 is provided on the surface of the transmission substrate holder 60 so as to cover the first opening 60 f.

[0278] Similarly, the receiving substrate holder 62 has a second opening 62 f for passing ultrasonic waves 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 62 f.

[0279] This provides the following effects.

[0280] If foreign matter is attached to the first protective member 70 or the second protective member 73, there is a risk of reduced intensity of ultrasonic waves received by the receiving sensor chip 56, leading to false detection. Therefore, in this case, the first protective member 70 or the second protective member 73 needs to be replaced or cleaned for maintenance.

[0281] In the present embodiment, the first protective member 70 is provided on the surface of the transmission substrate holder 60 so as to cover the first opening 60 f , and therefore replacement and maintenance of the first protective member 70 are facilitated.

[0282] Similarly, the second protective member 73 is provided on the surface of the receiving substrate holder 62 so as to cover the second opening 62 f , and therefore, replacement and maintenance of the second protective member 73 are facilitated.

[0283] In addition, as reference Figure 22 As described above, the transmitting sensor chip 53 and the receiving sensor chip 56 are inclined at the angle α1 , which is the first angle, with respect to the surface of the document P passing between the transmitting sensor chip 53 and the receiving sensor chip 56 .

[0284] Furthermore, 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 .

[0285] Furthermore, the angle α1 is different from the angle α2, and the angle α2 is gentler than the angle α1.

[0286] Thereby, the following effects can be obtained.

[0287] When the first protective member 70 and the second protective member 73 are parallel to the surface of the original document P passing between the sending sensor chip 53 and the receiving sensor chip 56, paper dust and the like are easily attached 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 relative to the surface of the original document P passing between the sending sensor chip 53 and the receiving sensor chip 56, the attachment of foreign matter such as paper dust and the like toward the first protective member 70 and the second protective member 73 can be suppressed.

[0288] In addition, the transmitting sensor chip 53 and the receiving sensor chip 56 are inclined at an angle α1 relative to the surface of the original document P passing between the transmitting sensor chip 53 and the receiving sensor chip 56, thereby suppressing multiple reflections of ultrasonic waves between the transmitting sensor chip 53 and the original document P, or between the receiving sensor chip 56 and the original document P.

[0289] Furthermore, since the angle α1 and the angle α2 are different, multiple reflections of ultrasonic waves between the transmitting sensor chip 53 and the first protective member 70 and between the receiving sensor chip 56 and the second protective member 73 can be suppressed.

[0290] In addition, as reference Figures 5 to 7 As described above, the scanner 1 forms the document conveyance path, or reading conveyance path R2, between the first roller pair 13 and the second roller pair 16. It includes a transmission-side path-forming member 36 that secures the transmission substrate holder 60. A detachable cover 37 is provided on the transmission-side path-forming member 36. When the cover 37 is attached, the transmission substrate holder 60 is covered by the cover 37. When the cover 37 is removed, the separation roller 15 can be replaced, and the transmission substrate holder 60 is exposed. In particular, the first protective member 70 is exposed.

[0291] This makes it possible to easily access the sending substrate holder 60. As a result, for example, replacement and maintenance of the first protective member 70 become easier.

[0292] The transmission substrate holder 60 also includes a fixing portion 60a to which the first protective member 70 is fixed. The transmission substrate 52 is fixed to the back side of the fixing portion 60a. The fixing portion 60a includes a first wall portion 60b, which is opposed to the side of the fixed transmission substrate 52 and covers at least a portion of the transmission substrate 52. Thus, if foreign matter attempts to pass around the side of the fixing portion 60a to the transmission substrate 52, the first wall portion 60b can prevent this.

[0293] <Relationship between the Ultrasonic Detection Unit Structure and Other Scanner Structures>

[0294] Next, the relative positional relationship between the configuration of the ultrasonic detection unit 50 and other configurations of the scanner 1 will be described.

[0295] First, refer to Figure 23 The positional relationship between the ultrasonic detection unit 50 and the first roller pair 13 will be described. Figure 23 : shows the positional relationship between the ultrasonic detection unit 50 and the first roller pair 13 as viewed from the upstream in the conveying direction Fp. Figure 23 In FIG. 1 , the feed roller 14 and the separation roller 15 constituting the first roller pair 13 are indicated by two-dot chain lines.

[0296] As shown in the figure, at least a portion of the transmitting sensor chip 53 and at least a portion of the receiving sensor chip 56 are located inside the range Ua1 of the first roller pair 13 in the normal direction Da relative to the document surface S at the nip position of the first roller pair 13. This can reduce the size of the device in the normal direction Da.

[0297] Furthermore, in this embodiment, the entire transmitting sensor chip 53 and the entire receiving sensor chip 56 are located within the range Ua1 in the normal direction Da. However, a portion of the transmitting sensor chip 53 and a portion of the receiving sensor chip 56 may be located within the range Ua1 in the normal direction Da. Alternatively, a portion of the transmitting sensor chip 53 and the entire receiving sensor chip 56 may be located within the range Ua1 in the normal direction Da. Alternatively, the entire transmitting sensor chip 53 and a portion of the receiving sensor chip 56 may be located within the range Ua1 in the normal direction Da.

[0298] Furthermore, in this embodiment, at least a portion of the receiving substrate 55 and at least a portion of the shielding member 91 are located inside the range Ua1 of the first roller pair 13 in the normal direction Da relative to the document surface S at the nip position of the first roller pair 13. This allows the device size in the normal direction Da to be reduced.

[0299] In addition, in this embodiment, the entire receiving substrate 55 and the entire shielding member 91 are located inside the range Ua1 in the normal direction Da, but a part of the receiving substrate 55 or a part of the shielding member 91 may be located inside the range Ua1 in the normal direction Da.

[0300] Reference numeral 14a denotes the rotation axis of the feed roller 14, and reference numeral 15a denotes the rotation axis of the separation roller 15. In this embodiment, the distance between the axial centers of the rotational shafts 14a and 15a, i.e., the inter-axial distance dk1, is 16.6 mm. This is smaller than the inter-sensor distance of 24.9 mm, i.e., the distance between the transmitting sensor chip 53 and the receiving sensor chip 56. This reduces the area occupied by the first roller pair 13 along the inter-axial distance dk1, thereby reducing the size of the device.

[0301] In addition, in this embodiment, the shaft diameter of the rotating shaft 14 a is 6.0 mm, and the shaft diameter of the rotating shaft 15 a is 3.0 mm 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.

[0302] Next, refer to Figure 24 The positional relationship between the ultrasonic detection unit 50 , the second roller pair 16 , and the third roller pair 20 will be described. Figure 24 The positional relationship among the ultrasonic detection unit 50 , the second roller pair 16 , and the third roller pair 20 as viewed from upstream in the conveyance direction Fp is shown.

[0303] exist Figure 24 , the second lower roller 17 and the second upper roller 18 constituting the second roller pair 16 are indicated by a two-dot chain line. In addition, the outline of the third lower roller 21 constituting the third roller pair 20 overlaps with the second lower roller 17, and the outline of the third upper roller 22 constituting the third roller pair 20 overlaps with the second upper roller 18.

[0304] In addition, as will be described in detail later, the second upper roller 18 and the third upper roller 22 are both arranged to advance and retreat relative to the opposing rollers. Figure 24 This shows a state where both the second upper roller 18 and the third upper roller 22 are in contact with the opposing rollers.

[0305] As shown in the figure, at least a portion of the transmitting sensor chip 53 and at least a portion of the receiving sensor chip 56 are located inside the range Ua2 of the second roller pair 16 or the third roller pair 20 in the normal direction Da relative to the document surface S at the nip position of the second roller pair 16 or the third roller pair 20. This can reduce the size of the device in the normal direction Da relative to the document surface S at the nip position of the second roller pair 16 or the third roller pair 20.

[0306] Furthermore, in this embodiment, the entire transmitting sensor chip 53 and the entire receiving sensor chip 56 are located within the range Ua2 in the normal direction Da. However, a portion of the transmitting sensor chip 53 and a portion of the receiving sensor chip 56 may also be located within the range Ua2 in the normal direction Da. Alternatively, a portion of the transmitting sensor chip 53 and the entire receiving sensor chip 56 may also be located within the range Ua2 in the normal direction Da. Alternatively, the entire transmitting sensor chip 53 and a portion of the receiving sensor chip 56 may also be located within the range Ua2 in the normal direction Da.

[0307] The relationship between the dimensions of the rotation axes 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 described again later.

[0308] Furthermore, in this embodiment, a portion of the transmitting substrate 52 and the entire receiving substrate 55 are located inside the range Ua1 in the normal direction Da. However, the entire transmitting substrate 52 and the entire receiving substrate 55 may also be located inside the range Ua1 in the normal direction Da. Alternatively, a portion of the transmitting substrate 52 and a portion of the receiving substrate 55 may also be located inside the range Ua1 in the normal direction Da. Alternatively, the entire transmitting substrate 52 and a portion of the receiving substrate 55 may also be located inside the range Ua1 in the normal direction Da.

[0309] In addition, 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, that is, the inter-axis distance dk2 is 15.4 mm, which is smaller than the distance between the sending sensor chip 53 and the receiving sensor chip 56, that is, the inter-sensor distance of 24.9 mm.

[0310] 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 inter-axial distance dk2 , thereby reducing the size of the device.

[0311] Next, the sending substrate 52 and the receiving substrate 55 are tilted relative to the normal direction Da of the original document surface S passing between the sending sensor chip 53 and the receiving sensor chip 56, and the sending surface 53a of the sending sensor chip 53 is along the surface of the sending substrate 52, and the receiving surface 56a of the receiving sensor chip 56 is along the surface of the receiving substrate 55.

[0312] Furthermore, at least a portion of the transmitting substrate 52 and at least a portion of the receiving substrate 55 are located within the range of the second roller pair 16 or the third roller pair 20 in the normal direction Da relative to the document surface S at the nipping position of the second roller pair 16 or the third roller pair 20. This can reduce the size of the device in the normal direction Da.

[0313] Furthermore, in this embodiment, the entire transmitting substrate 52 and a portion of the receiving substrate 55 are located inside the range Ua2 in the normal direction Da. However, a portion of the transmitting substrate 52 and a portion of the receiving substrate 55 may also be located inside the range Ua2 in the normal direction Da. Alternatively, a portion of the transmitting substrate 52 and the entire receiving substrate 55 may also be located inside the range Ua2 in the normal direction Da. Alternatively, the entire transmitting substrate 52 and the entire receiving substrate 55 may also be located inside the range Ua2 in the normal direction Da.

[0314] In this embodiment, the entire transmitting sensor chip 53 and the entire receiving sensor chip 56 are located within the range Ua2 in the normal direction Da. However, a portion of the transmitting sensor chip 53 and a portion of the receiving sensor chip 56 may also be located within the range Ua2 in the normal direction Da. Alternatively, a portion of the transmitting sensor chip 53 and the entire receiving sensor chip 56 may also be located within the range Ua2 in the normal direction Da. Alternatively, the entire transmitting sensor chip 53 and a portion of the receiving sensor chip 56 may also be located within the range Ua2 in the normal direction Da.

[0315] In the present embodiment, a portion of the receiving substrate 55 and a portion of the shield member 91 are located inside the range Ua2 in the normal direction Da. This can reduce the size of the device in the normal direction Da.

[0316] In addition, in this embodiment, part of the receiving substrate 55 and part of the shielding member 91 are located inside the range Ua1 in the normal direction Da, but the entire receiving substrate 55 or the entire shielding member 91 may also be located inside the range Ua1 in the normal direction Da.

[0317] Next, refer to Figure 25 The structure of the second roller pair 16 will be further described.

[0318] In this embodiment, two second roller pairs 16 are provided in the X-axis direction, that is, in the document width direction. The two second roller pairs 16 are provided at symmetrical positions across the center position CL of the document P in the document width direction.

[0319] Reference numeral 17 a denotes a rotation axis of the second lower roller 17 .

[0320] Reference numeral 18a1 denotes a rotation shaft located between the two second upper rollers 18 , and reference numeral 18a2 denotes rotation shafts located on both sides of the two second upper rollers 18 . The shaft diameter of the rotation shaft 18a1 is smaller than that of the rotation shaft 18a2 .

[0321] The rotation shaft 18a2 located in the +X direction is connected to the first universal joint 31A. A second universal joint 31B is provided in the +X direction relative to the first universal joint 31A, and the first universal joint 31A and the second universal joint 31B are connected by the rotation shaft 18a3.

[0322] Since the second upper roller 18 is moved forward and backward relative to the second lower roller 17 while receiving power, the first universal joint 31A and the second universal joint 31B can be used to drive the second upper roller 18 while moving forward and backward relative to the second lower roller 17 .

[0323] exist Figure 25 The lower figure shows the state in which the second upper roller 18 and the second lower roller 17 are in contact. Figure 25 In the figure, the upper figure shows a state where the second upper roller 18 is farthest from the second lower roller 17. Reference symbol M1 represents the range in which the second upper roller 18 moves.

[0324] As shown in the figure, in this embodiment, the entire receiving sensor chip 56 and the entire receiving substrate 55 are located inside the range M1 in the normal direction Da, so the device size in the normal direction Da can be suppressed.

[0325] Furthermore, in this embodiment, the entire receiving sensor chip 56 and the entire receiving substrate 55 are located inside the range M1 in the normal direction Da. However, a portion of the receiving sensor chip 56 and a portion of the receiving substrate 55 may be located inside the range M1 in the normal direction Da. Alternatively, the entire receiving sensor chip 56 and a portion of the receiving substrate 55 may be located inside the range M1 in the normal direction Da.

[0326] Furthermore, 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 .

[0327] In this embodiment, the shaft diameter of the rotating shaft 17a is 6.0 mm. The shaft diameters of the rotating shaft 18a1, 18a2, and 18a3 are 4.0 mm, 5.0 mm, and 4.5 mm, respectively, which are all larger than the thickness of the transmitting sensor chip 53 or the receiving sensor chip 56.

[0328] Furthermore, as described above, the path length between the first roller pair 13 and the second roller pair 16, that is, the path length of the downstream feed path R1, is shorter than the path length between the second roller pair 16 and the third roller pair 20, that is, the path length of the reading transport path R2. This reduces the path length between the first roller pair 13 and the second roller pair 16, and thus reduces the size of the device.

[0329] In addition, in this embodiment, the transmitting substrate 52 and the receiving substrate 55 are as shown in FIG. Figures 13 to 15 As described above, the long side E2 and the short side E1 are provided, and the short side E1 is arranged along the conveying direction Fp. This allows the first roller pair 13 and the second roller pair 16 to be brought close to each other in the conveying direction Fp, thereby promoting miniaturization of the device.

[0330] Furthermore, the lengths of the short sides E1 of the transmitting substrate 52 and the receiving substrate 55 are shorter than the length of the glass plate 32 e in the conveyance direction Fp.

[0331] Here, refer to Figure 26 The structures of the first reading unit 32 and the second reading unit 33 will be described. The structures of the first reading unit 32 and the second reading unit 33 are basically the same, and the structure of the first reading unit 32 will be described below.

[0332] The first reading unit 32 includes a lower housing 32f and an upper housing 32g. The lower housing 32f includes a sensor substrate 32a. A linear image sensor 32b, an example of a reading sensor, is provided on the sensor substrate 32a. The image sensor 32b receives reflected light from the document P via a lens 32c. Reference numeral 32d denotes a light source that illuminates the document P.

[0333] The upper housing 32g is provided with a glass plate 32e. The glass plate 32e not only transmits light reflected by the document P toward the lens 32c, but also has a function of contacting the document P and guiding the document P downstream.

[0334] As described above, the short sides E1 of the transmitting substrate 52 and the receiving substrate 55 are shorter than the length of the glass plate 32e in the conveyance direction Fp. Furthermore, in this embodiment, the short sides E1 of the transmitting substrate 52 and the receiving substrate 55 are 8.6 mm long, the long sides E2 are 26.8 mm long, and the length of the glass plate 32e in the conveyance direction Fp is 12.6 mm.

[0335] This can reduce the length of the short sides E1 of the transmitter substrate 52 and the receiver substrate 55 in the transport direction Fp. As a result, the first roller pair 13 and the second roller pair 16 can be brought closer together in the transport direction Fp, further promoting miniaturization of the device.

[0336] In addition, in the present embodiment, the thickness of the glass plate 32 e is 1.1 mm, which is larger than the thickness of the transmitting sensor chip 53 or the receiving sensor chip 56 , which is 0.578 mm.

[0337] then, Figure 27 The positional relationship between the transmitting substrate 52 and the transmitting sensor chip 53 and the sensor substrate 32a and the image sensor 32b is shown when the transmitting substrate 52 and the transmitting sensor chip 53 are viewed from the upstream of the conveying direction Fp. Figure 27 In FIG, the sensor substrate 32 a and the image sensor 32 b are indicated by two-dot chain lines.

[0338] As shown in the figure, the transmitting sensor chip 53 is located further to the +Da side, i.e., to the second reading unit 33 side, than the image sensor 32b in the normal direction Da. This reduces the amount by which the transmitting sensor chip 53 protrudes from the first reading unit 32 in the normal direction Da to the -Da side, i.e., the lower side, and thus reduces the size of the device in the normal direction Da.

[0339] then, Figure 28 The positional relationship between the transmitting substrate 52 and the transmitting sensor chip 53 and the second reading unit 33 when the transmitting substrate 52 and the transmitting sensor chip 53 are viewed from the upstream of the conveying direction Fp is shown. Figure 28 In FIG. 1 , the outer shape of the second reading section 33 and the image sensor 32B included in the second reading section 33 are indicated by two-dot chain lines.

[0340] The second reading unit 33 moves forward and backward relative to the first reading unit 32. Figure 28 The figure below shows the state farthest from the first reading unit 32. Figure 28 The upper diagram shows a state where the first reading section 32 is most advanced. The range indicated by reference numeral M2 shows an area where the second reading section 33 is displaced.

[0341] As shown in the figure, at least a portion of the receiving sensor chip 56 is located inside the range M2 in the normal direction Da. This can suppress the device size in the normal direction Da.

[0342] Similarly, at least a portion of the receiving substrate 55 is located inside the range M2 in the normal direction Da. This can suppress the device size in the normal direction Da.

[0343] Furthermore, in this embodiment, the entire receiving sensor chip 56 and the entire receiving substrate 55 are located inside the range M2 in the normal direction Da. However, a portion of the receiving sensor chip 56 and a portion of the receiving substrate 55 may be located inside the range M2 in the normal direction Da. Alternatively, the entire receiving sensor chip 56 and a portion of the receiving substrate 55 may be located inside the range M2 in the normal direction Da.

[0344] then, Figure 29 The occupied areas of the first roller pair 13 , the second roller pair 16 , the conveying motor 47 , the transmitting sensor chip 53 , the transmitting substrate 52 , the receiving sensor chip 56 , and the receiving substrate 55 are shown when viewed from the X-axis direction.

[0345] As shown in the figure, at least a portion of the transmission substrate 52 and at least a portion of the transmission sensor chip 53 are located within the area occupied by the conveying motor 47. This can suppress an increase in the size of the device.

[0346] In addition, in this embodiment, a portion of the transmitting substrate 52 and the entire transmitting sensor chip 53 are located within the occupied area of ​​the conveying motor 47, but the entire transmitting substrate 52 and the entire transmitting sensor chip 53 may be located within the occupied area of ​​the conveying motor 47, or a portion of the transmitting substrate 52 and a portion of the transmitting sensor chip 53 may be located within the occupied area of ​​the conveying motor 47.

[0347] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and such modifications are naturally included in the scope of the present invention.

[0348] For example, in the above embodiment, the medium conveying device 100 is applied to the scanner 1 as an example of an image reading device, but is not limited to this and can also be applied to a recording device that records media, or a post-processing device that performs post-processing such as binding and punching on media.

Claims

1. A medium conveying device, characterized in that: have: A first roller pair transports the medium in a transport direction; a second roller pair disposed downstream of the first roller pair in the conveying direction; and an ultrasonic detection unit arranged between the first roller pair and the second roller pair in the conveying direction; The ultrasonic detection unit includes: A transmitting sensor chip is directed toward the first side of the transported medium and emits ultrasonic waves along a first axis; a receiving sensor chip, arranged at a position on the first axis with the medium sandwiched therebetween together with the transmitting sensor chip, for receiving ultrasonic waves; a transmitting substrate, provided with the transmitting sensor chip, and having the transmitting sensor chip mounted on a substrate surface; a receiving substrate, provided with the receiving sensor chip, and the receiving sensor chip is placed on a first substrate surface; an amplifier, disposed on the receiving substrate, for amplifying the ultrasonic receiving signal received by the receiving sensor chip; as well as a shielding member, provided on the receiving substrate, covering at least a portion of the amplifier; The height of the receiving sensor chip relative to the receiving substrate is lower than the height of the shield member relative to the receiving substrate.

2. The medium conveying device according to claim 1, characterized in that: The first axis is inclined relative 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 thinner than the thickness of the transmitting substrate. The thickness of the receiving sensor chip is thinner 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 located within the range of the second roller pair in a normal direction relative to the surface of the medium at the nip position of the second roller pair.

3. The medium conveying device according to claim 1, characterized in that: In the receiving substrate, the amplifier and the shielding member are provided on a substrate surface opposite to the first substrate surface on which the receiving sensor chip is mounted.

4. The medium conveying device according to claim 1, characterized in that: The receiving substrate is provided with a connector on a substrate surface opposite to the first substrate surface facing the transmitting sensor chip. The amplifier and the shield member are arranged on a surface of the receiving substrate where the connector is provided.

5. The medium conveying device according to claim 1, characterized in that: On the receiving substrate, the amplifier is arranged on the first substrate surface on which the receiving sensor chip is mounted. The shield member covers not only the amplifier but also the receiving sensor chip.

6. The medium conveying device according to claim 1, characterized in that: At least a portion of the receiving substrate and at least a portion of the shielding member are located within the range of the first roller pair in a normal direction relative to the surface of the medium at the clamping position of the first roller pair. Alternatively, the medium is located within the range of the second roller pair in the normal direction of the surface of the medium at the clamping position relative to the second roller pair.

7. The medium conveying device according to claim 1, characterized in that: The receiving sensor chip includes a piezoelectric element. The first axis is inclined relative to a plane of the medium passing between the transmitting sensor chip and the receiving sensor chip. When calibrating the ultrasonic detection unit, ultrasonic waves are received by the receiving sensor chip while a bias voltage is applied to the receiving sensor chip including the piezoelectric element, and the received signal is amplified by the amplifier.

8. The medium conveying device according to claim 7, characterized in that: The first axis is inclined relative to a plane of the medium passing between the transmitting sensor chip and the receiving sensor chip. When the ultrasonic detection unit detects overlapping feed of media, the ultrasonic wave is received by the receiving sensor chip with a bias voltage applied to the receiving sensor chip, and the amplifier amplifies the received signal.

9. An image reading device, characterized in that: have: The medium conveying device according to any one of claims 1 to 8; and The reading unit is located downstream of the second roller pair in the conveying direction and reads an image on the medium.

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