Image reading device

Abstract

To evade the possible deterioration of manuscript reading quality in a reading unit when a thick manuscript like a booklet is read by the reading unit.SOLUTION: A scanner 1 includes: a first feed roller pair 16 which feeds a manuscript G; a reading unit 30 which reads the manuscript G; a second feed roller pair 20 which feeds the manuscript G; a feed motor 50; and a pressing part 41. The feed motor 50 rotates both rollers of the first feed roller pair 16 and both rollers of the second feed roller pair 20. The pressing part 41 can change first pressing force generated at the first feed roller pair 16 and second pressing force generated at the second feed roller pair 20. The pressing part 41 changes the second pressing force such that second pressing force when the first feed roller pair 16 feeds the manuscript G whereas the second feed roller pair 20 does not feed the manuscript G is smaller than second pressing force when neither the first feed roller pair 16 nor the second feed roller pair 20 feeds the manuscript G.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image reading apparatus.

Background Art

[0002] In the image reading apparatus of Patent Document 1, a first feed roller, a second feed roller, a first pressure roller, and a second pressure roller are driven by one motor. Elastic force by a biasing spring is applied to each roller.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration such as that of Patent Document 1, when a thick document such as a booklet is read by a reading unit, the document is conveyed to a position facing the reading unit by a first roller pair located upstream in the conveyance direction with respect to the reading unit, and then the document is read. Here, when the downstream end portion of the read document enters the nip of the second roller pair, the downstream end portion of the document enters while greatly widening the interval between the two rollers in the second roller pair. For this reason, the load due to the intrusion of the document into the nip of the second roller pair is applied to the first roller pair, and thus the conveyance speed of the document by the first roller pair may decrease. In this case, there is a risk that the reading quality of the document in the reading unit may deteriorate.

Means for Solving the Problems

[0005] To solve the above problems, an image reading apparatus according to the present invention includes a first transport roller pair having a first roller and a second roller, the first transport roller pair that transports a document while pressing it, a reading unit that reads the document transported by the first transport roller pair, a second transport roller pair having a third roller and a fourth roller, the second transport roller pair that is located downstream of the reading unit in the transport direction of the document and transports the document while pressing it, a drive unit that applies power to the first roller, the second roller, the third roller, and the fourth roller, and a pressing unit that can change a first pressing force generated between the first roller and the second roller and a second pressing force generated between the third roller and the fourth roller. The pressing unit changes the second pressing force such that the second pressing force when the first transport roller pair is transporting the document and the second transport roller pair is not transporting the document is lower than the second pressing force when neither the first transport roller pair nor the second transport roller pair is transporting the document.

Brief Description of the Drawings

[0006]

Figure 1

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Mode for Carrying Out the Invention

[0007] Hereinafter, the present invention will be schematically described. The image reading apparatus according to the first aspect includes a first pair of conveying rollers having a first roller and a second roller, the first pair of conveying rollers that convey while pressing a document; a reading unit that reads the document conveyed by the first pair of conveying rollers; a second pair of conveying rollers having a third roller and a fourth roller, the second pair of conveying rollers being located downstream of the reading unit in the conveying direction of the document and conveying the document while pressing it; a driving unit that applies power to the first roller, the second roller, the third roller, and the fourth roller; and a pressing unit that can change a first pressing force generated between the first roller and the second roller and a second pressing force generated between the third roller and the fourth roller. The pressing unit is characterized in that the second pressing force when the first pair of conveying rollers are conveying the document and the second pair of conveying rollers are not conveying the document is lower than the second pressing force when neither the first pair of conveying rollers nor the second pair of conveying rollers are conveying the document.

[0008] According to this aspect, when a thick document such as a booklet is read by the reading unit, the document receives the first pressing force by passing through the nip between the first roller and the second roller, and is conveyed in the conveying direction by the first pair of conveying rollers. Then, when the document passes through a position facing the reading unit, it is read by the reading unit. The read document is conveyed toward the second pair of conveying rollers. The pressing unit changes the second pressing force so that the second pressing force when the first pair of conveying rollers are conveying the document and the second pair of conveying rollers are not conveying the document is lower than the second pressing force when neither the first pair of conveying rollers nor the second pair of conveying rollers are conveying the document. Here, when the downstream end of the read manuscript in the conveyance direction enters between the third roller and the fourth roller, the downstream end of the manuscript tries to enter while widening the gap between the third roller and the fourth roller. However, since the second pressing force is kept low, the load acting on the first pair of conveyance rollers becomes small. As a result, a decrease in the conveyance speed of the manuscript by the first pair of conveyance rollers is suppressed. In this way, since a decrease in the conveyance speed of the manuscript in the first pair of conveyance rollers is suppressed, a decrease in the reading quality of the manuscript in the reading unit can be suppressed.

[0009] The image reading apparatus according to the second aspect is, in the first aspect, characterized in that when the first pair of conveyance rollers conveys the manuscript and the second pair of conveyance rollers does not convey the manuscript, the pressing unit increases the first pressing force compared to when the first pair of conveyance rollers and the second pair of conveyance rollers convey the manuscript, and when the second pair of conveyance rollers conveys the manuscript and the first pair of conveyance rollers does not convey the manuscript, the pressing unit increases the second pressing force compared to when the first pair of conveyance rollers and the second pair of conveyance rollers convey the manuscript. According to this aspect, when only the first pair of conveyance rollers or only the second pair of conveyance rollers conveys the manuscript, the pressing force on the manuscript is increased. As a result, slipping of the first pair of conveyance rollers or the second pair of conveyance rollers with respect to the manuscript is suppressed, so that the conveyance state of the manuscript can be stabilized.

[0010] The image reading apparatus according to the third aspect is, in the first aspect or the second aspect, characterized in that when the first pair of conveyance rollers and the second pair of conveyance rollers both convey the manuscript, the pressing unit makes the first pressing force and the second pressing force equal. According to this aspect, the same effects as in the first aspect or the second aspect can be obtained.

[0011] In the image reading apparatus according to the fourth aspect, in any one of the first aspect to the third aspect, the pressing unit includes: a first pressing unit capable of changing the first pressing force by changing the force acting on the first rotation shaft of the first roller; a second pressing unit capable of changing the second pressing force by changing the force acting on the second rotation shaft of the third roller; and an interlocking unit that interlocks a first operation in which the first pressing unit changes the first pressing force and a second operation in which the second pressing unit changes the second pressing force. According to this aspect, by interlocking the first operation and the second operation, the first pressing force and the second pressing force are changed. As a result, compared with a configuration in which the mechanism for changing the first pressing force and the mechanism for changing the second pressing force are driven independently, the configuration for changing the first pressing force and the second pressing force can be made simpler. Note that "change" in the fourth aspect is a concept that includes not only "change" when reducing the second pressing force in the first aspect, but also "change" when increasing the second pressing force.

[0012] In the image reading apparatus according to the fifth aspect, in the fourth aspect, the interlocking unit is a shaft member provided rotatably, one of the first pressing unit and the second pressing unit is fixed to the shaft member, and a gap portion is provided between the other of the first pressing unit and the second pressing unit and the shaft member to shift a start point of the first operation and a start point of the second operation. In a configuration where the first pressing unit and the second pressing unit are integrated, when the first pressing unit is slightly displaced, the second pressing unit is also displaced almost simultaneously. Similarly, when the second pressing unit is slightly displaced, the first pressing unit is also displaced almost simultaneously. Thus, in a configuration where the first pressing unit and the second pressing unit are integrated, fluctuations in the pressing force are likely to occur in each of the first pressing unit and the second pressing unit. According to this aspect, although the first operation and the second operation are interlocked, the start timing of the first operation and the start timing of the second operation are shifted by the gap portion. Thereby, even if one of the first pressing portion and the second pressing portion is slightly displaced, it is possible to suppress the other from being displaced simultaneously, so that fluctuations in the first pressing force and the second pressing force can be suppressed.

[0013] The image reading apparatus according to the sixth aspect is, in the fourth aspect or the fifth aspect, characterized in that the first pressing portion presses the central portion in the axial direction of the first rotation shaft, and the second pressing portion presses the central portion in the axial direction of the second rotation shaft. According to this aspect, since the pressing portions of the first rotation shaft and the second rotation shaft are aligned at the central portion in the axial direction, it is possible to equalize the loads acting in the axial direction on each of the first rotation shaft and the second rotation shaft.

[0014] The image reading apparatus according to the seventh aspect is, in any one of the first aspect to the sixth aspect, provided upstream of the first pair of conveying rollers in the conveying direction, and feeds the document to the first pair of conveying rollers, and a correcting member provided between the feeding roller and the first pair of conveying rollers and contacting the document, wherein the correcting member contacts the central portion in the width direction intersecting the conveying direction of the document fed by the feeding roller. According to this aspect, by the correcting member contacting the central portion in the width direction of the document, it is possible to suppress the central portion of the document from rising in a direction away from the document conveying path. Thereby, it is possible to suppress conveyance failures such as wrinkles and jams of the document when feeding the document to the first pair of conveying rollers.

[0015] The image reading apparatus according to the eighth aspect is, in the seventh aspect, characterized in that the correcting member guides the document to the nip between the first roller and the second roller. According to this aspect, when the original document comes into contact with the correction member, it is guided to the nip between the first roller and the second roller as it is conveyed. As a result, compared to a configuration without the correction member, it becomes easier for the original document to enter the nip between the first roller and the second roller.

[0016] The image reading apparatus according to the ninth aspect is the image reading apparatus according to the seventh aspect or the eighth aspect, wherein the correction member is provided so as to be swingable toward the first rotation axis of the first roller. According to this aspect, when the thin original document is fed to the first pair of conveying rollers, by the thin original document coming into contact with the correction member, it is possible to suppress a part of the thin original document from lifting in a direction away from the conveyance path. Since the reaction force exerted by the thin original document on the correction member is small, the amount of swing of the correction member is small. Furthermore, when the thick original document is fed to the first pair of conveying rollers, the reaction force exerted by the thick original document on the correction member is large. For this reason, the correction member is swung toward the first rotation axis. In other words, the correction member is retracted from the conveyance path of the original document. As a result, an increase in the reaction force acting on the original document being conveyed from the correction member is suppressed, so that the conveyance load on the feeding roller when feeding the thick original document can be suppressed.

[0017] Hereinafter, the present invention will be specifically described. As shown in FIGS. 1 and 2, as an example of an image reading apparatus, a scanner 1 capable of reading at least one of the first surface GA and the opposite second surface GB of an original document G will be described. The scanner 1 is a so-called sheet feed type scanner that reads while moving the original document G with respect to a reading unit 30 described later. In this specification, the original document G includes not only sheets but also card-shaped or booklet-shaped original documents G.

[0018] Still, in each figure, the X - Y - Z coordinate system shown has the X - axis direction being the width direction of the apparatus and also the width direction of the document G. The Y - axis direction is the depth direction of the apparatus, and the Z - axis direction is the direction along the vertical direction. In the present embodiment, the +Y direction is defined as the direction from the back surface to the front surface of the apparatus, and the -Y direction is defined as the direction from the front surface to the back surface of the apparatus. Also, when viewed from the front surface of the apparatus, the left direction is the +X direction, and the right direction is the -X direction. Further, the upper side in the Z - axis direction is the +Z direction, and the lower side is the -Z direction.

[0019] Hereinafter, the direction in which the conveyance path R of the document G extends at a position facing the reading unit 30 described later is defined as the A - axis direction. Also, among the A - axis directions, the direction in which the document G is conveyed is defined as the +A direction. That is, the +A direction is an example of the conveyance direction. The A - axis direction is orthogonal to the X - axis direction. The A - axis direction is the direction toward the position in the +Y direction and the -Z direction. The direction orthogonal to both the A - axis direction and the X - axis direction is defined as the B - axis direction. Among the B - axis directions, the direction having a +Z - direction component is the +B direction, and the direction having a -Z - direction component is the -B direction.

[0020] Specifically, the scanner 1 includes an apparatus main body 2 and a stand 6 that rotatably supports the apparatus main body 2. The apparatus main body 2 is configured to include a first unit 3, a second unit 4, and a third unit 5. Also, in the apparatus main body 2, a conveyance path R (described later) through which the document G is conveyed is formed.

[0021] The first unit 3 includes an upper opening / closing unit 10, a separation roller 15, a second roller 18, a fourth roller 22, a control unit 34, an attitude switching motor 40, and a conveyance motor 50 (Fig. 5). The second unit 4 is located in the +Y direction with respect to the first unit 3. The third unit 5 is located in the +Y direction with respect to the second unit 4.

[0022] The second unit 4 and the third unit 5 are rotatably provided about a frame rotation axis (not shown). The frame rotation axis forms a rotation axis center parallel to the X-axis direction. The second unit 4 and the third unit 5 can rotate integrally about the frame rotation axis with respect to the first unit 3. By rotating the second unit 4 and the third unit 5 with respect to the first unit 3, a manuscript feeding path R1 and a reading conveyance path R2, which will be described later, are exposed.

[0023] The third unit 5 can be rotated about a frame rotation axis (not shown) with respect to the first unit 3 and the second unit 4. By rotating the third unit 5 with respect to the first unit 3 and the second unit 4, it is possible to expose a reverse conveyance path R3, which will be described later.

[0024] The apparatus main body 2 can rotate about a main body rotation axis 6A with respect to the stand 6. In the present embodiment, the apparatus main body 2 can be held in two postures by being rotated. The posture of the apparatus main body 2 shown in FIG. 1 is referred to as a normal reading posture. The posture of the apparatus main body 2 shown in FIG. 2 is referred to as a booklet reading posture. The switching of the posture of the apparatus main body 2 is performed by rotating a gear that meshes with a rack portion (not shown) of the stand 6 by a posture switching motor 40 (FIG. 3). The operation of the posture switching motor 40 is controlled by a control unit 34 (FIG. 3). Here, the surface on which the stand 6 is placed is defined as a placement surface D. As an example, the placement surface D is a plane along the X-Y plane.

[0025] As shown in FIG. 2, an angle formed between a reading conveyance path R2, which will be described later, and the placement surface D is defined as a posture angle θ [°]. The posture angle θ in the case of the booklet reading posture is smaller than the posture angle θ in the case of the normal reading posture. In the normal reading posture, the projection area of the apparatus main body 2 on the placement surface D is the smallest for the scanner 1. That is, in the normal reading posture, the footprint of the apparatus main body 2 is the smallest. Here, the footprint in this specification corresponds to the occupied area of the apparatus main body 2 in the X-Y plane when the apparatus main body 2 is viewed from above in the Z-axis direction.

[0026] On the front surface of the apparatus main body 2, an operation unit (not shown) including a power button is provided. On the side surface of the apparatus main body 2 in the +X direction, a connection part (not shown) is provided. The connection part includes a power plug for supplying power to the apparatus main body 2 and a connector for transmitting and receiving information.

[0027] Next, the configuration of the conveyance path R of the document G in the scanner 1 will be described. The first unit 3 has an upper opening / closing part 10 that functions as a lid for the conveyance path R. The upper opening / closing part 10 opens and closes the feeding port 19 by rotating about an axis (not shown). A document support part 11 is formed on the upper opening / closing part 10. The document G to be fed is supported in an inclined posture by the document support part 11. When a plurality of documents G are supported by the document support part 11, the uppermost document G is sent out downstream in the +A direction by the feeding roller 14. On the document support part 11, edge guides 12 for guiding both end portions of the document G in the X direction are provided. The edge guides 12 are arranged at intervals in the X direction and are provided slidably in the X-axis direction. In the scanner 1, the document G is fed, for example, by a center feeding method.

[0028] The feeding roller 14 is provided in the second unit 4. Specifically, the feeding roller 14 is provided upstream in the +A direction from the first conveyance roller pair 16 described later. The feeding roller 14 rotates by obtaining power from a conveyance motor 50 (FIG. 3) described later. Then, the feeding roller 14 feeds the document G to the first conveyance roller pair 16. At a position facing the feeding roller 14 in the first unit 3, a separation roller 15 is provided. The separation roller 15 is given rotational torque by a torque limiter (not shown) to suppress double feeding of the document G. The feeding roller 14 and the separation roller 15 are provided, for example, at the central position in the X-axis direction. Note that a separation pad may be provided instead of the separation roller 15. In this embodiment, a feed roller 14 is provided above the document placed on the document support unit 11 and is configured to feed from the topmost document. However, a feed roller 14 may be provided below the document placed on the document support unit 11 and be configured to feed from the lowermost document.

[0029] Downstream of the feed roller 14 and the separation roller 15, a first pair of conveyance rollers 16 for conveying the document G is provided. The first pair of conveyance rollers 16 includes a first roller 17 provided in the second unit 4 and a second roller 18 provided in the first unit 3. The first pair of conveyance rollers 16 conveys the document G while rotating while pressing it. The first roller 17 is provided so as to be able to advance and retreat in the B-axis direction with respect to the second roller 18, and is pressed toward the second roller 18 by a first pressing member 42 (FIG. 5) described later.

[0030] As shown in FIG. 5, the first roller 17 has a columnar shaft portion 17A as an example of a first rotation shaft and two roller portions 17B provided on the shaft portion 17A. The two roller portions 17B are respectively positioned in the +X direction and the -X direction with respect to the center of the shaft portion 17A in the X-axis direction. Both ends of the shaft portion 17A in the X-axis direction are rotatably supported by two bearing members 23.

[0031] The two bearing members 23 are provided so as to be movable in the B-axis direction on a frame (not shown) of the second unit 4 (FIG. 1). In other words, the two bearing members 23 have a function of guiding the shaft portion 17A in the B-axis direction. Note that the two bearing members 23 have a function of restricting movement of the shaft portion 17A in the X-axis direction and the Y-axis direction. The end portion of the shaft portion 17A in the +X direction is connected to a universal joint 59. Note that the bearing member 23 may be pressed in the -B direction by a pressing member (for example, a coil spring). FIG. 16 shows such a modification, and reference numeral 25 is a coil spring. Coil springs 25 are in contact with the two bearing members 23 respectively, and the coil spring 25 applies a pressing force in the -B direction to the bearing member 23.

[0032] As shown in FIG. 2, the second roller 18 has a columnar shaft portion 18A and two roller portions 18B provided on the shaft portion 18A. The two roller portions 18B are respectively located in the +X direction and the -X direction with respect to the center of the shaft portion 18A in the X-axis direction.

[0033] Both the first roller 17 and the second roller 18 obtain power from a conveyance motor 50 (FIG. 3) described later and rotate. When the second unit 4 is closed with respect to the first unit 3, the first roller 17 and the second roller 18 contact each other to form the first nip N1. When the second unit 4 is opened with respect to the first unit 3, the first roller 17 separates from the second roller 18.

[0034] Downstream of the first conveyance roller pair 16 in the +A direction, a reading unit 30 for reading an image of the document G is provided. The reading unit 30 has a first reading unit 32 and a second reading unit 33 facing each other in the B-axis direction. In the present embodiment, the first reading unit 32 and the second reading unit 33 are configured by a contact image sensor module (CISM) as an example. The reading unit 30 reads the document G conveyed by the first conveyance roller pair 16.

[0035] The first reading unit 32 is provided in the first unit 3. The first reading unit 32 reads the second surface GB of the document G supported by the document support portion 11. The first reading unit 32 has a contact glass 32A. The second reading unit 33 is provided in the second unit 4. The second reading unit 33 reads the first surface GA of the document G supported by the document support portion 11. The second reading unit 33 has a contact glass 33A. Note that the second reading unit 33 is provided so as to be movable in the B-axis direction. Downstream of the reading unit 30 in the +A direction, a second conveyance roller pair 20 is provided.

[0036] The second transport roller pair 20 has a third roller 21 provided in the second unit 4 and a fourth roller 22 provided in the first unit 3. The second transport roller pair 20 transports the document G while rotating while pressing it. The third roller 21 is provided so as to be able to move forward and backward in the B-axis direction with respect to the fourth roller 22, and is pressed toward the fourth roller 22 by a second pressing member 62 (FIG. 5) described later.

[0037] As shown in FIG. 5, the third roller 21 has a columnar shaft portion 21A as an example of the second rotation shaft, and two roller portions 21B provided on the shaft portion 21A. The two roller portions 21B are respectively located in the +X direction and the -X direction with respect to the center of the shaft portion 21A in the X-axis direction. Both ends of the shaft portion 21A in the X-axis direction are rotatably supported by two bearing members 27.

[0038] The two bearing members 27 are provided so as to be movable in the B-axis direction on a frame (not shown) of the second unit 4 (FIG. 1). In other words, the two bearing members 27 have a function of guiding the shaft portion 21A in the B-axis direction. The bearing member 27 has, as an example, the same configuration as that of the bearing member 23. Note that the two bearing members 27 have a function of restricting the movement of the shaft portion 21A in the X-axis direction and the Y-axis direction. The +X direction end of the shaft portion 21A is connected to a universal joint 59. Note that the bearing member 27 may be pressed in the -B direction by a pressing member (for example, a coil spring). FIG. 16 shows such a modification, and reference numeral 25 is a coil spring. Coil springs 25 are in contact with the two bearing members 27, respectively, and the coil spring 25 applies a pressing force in the -B direction to the bearing member 27.

[0039] As shown in FIG. 2, the fourth roller 22 has a columnar shaft portion 22A and two roller portions 22B provided on the shaft portion 22A. The two roller portions 22B are respectively located in the +X direction and the -X direction with respect to the center of the shaft portion 22A in the X-axis direction.

[0040] Both the third roller 21 and the fourth roller 22 are rotated by obtaining power from a conveyance motor 50 (FIG. 3) described later. When the second unit 4 is closed with respect to the first unit 3, the third roller 21 and the fourth roller 22 come into contact with each other to form the second nip N2. When the second unit 4 is opened with respect to the first unit 3, the third roller 21 is separated from the fourth roller 22.

[0041] In the apparatus main body 2, as an example, the conveyance path R is constituted by a document feeding path R1, a reading conveyance path R2, a reversing conveyance path R3 (FIG. 1), and a non-reversing conveyance path R4 (FIG. 2). Note that since the reversing conveyance path R3 and the non-reversing conveyance path R4 are switched, both do not constitute the conveyance path R at the same time.

[0042] The document feeding path R1 is a path from the nip position between the feeding roller 14 and the separation roller 15 to the first nip N1. The reading conveyance path R2 is a linear path extending from the first nip N1 to the second nip N2 via a position facing the reading unit 30. The reversing conveyance path R3 (FIG. 1) is a path located downstream of the reading conveyance path R2 when the apparatus main body 2 is in the normal reading posture. After reading, the document G is reversed upward in the reversing conveyance path R3 and discharged obliquely upward from the first discharge port 37. The reversing conveyance path R3 is provided with a third conveyance roller pair 24 and a fourth conveyance roller pair 28.

[0043] The non-reversing conveyance path R4 is a path located downstream of the reading conveyance path R2 when the apparatus main body 2 is in the booklet reading posture. After reading, the document G is discharged obliquely downward from the second discharge port 38 without being reversed in the non-reversing conveyance path R4. Note that the second conveyance roller pair 20 functions as a discharge roller pair that discharges the document from the non-reversing conveyance path R4.

[0044] The switching between the reversing conveyance path R3 (FIG. 1) and the non-reversing conveyance path R4 is performed by a flap 35. The flap 35 is rotated by a solenoid (not shown), enabling the conveyance of the document G in one of the reverse conveyance path R3 and the non-reverse conveyance path R4 and restricting the conveyance of the document G to the other. In the present embodiment, the flap 35 is configured to rotate in conjunction with the switching of the posture of the apparatus main body 2.

[0045] Referring to FIG. 3, the control system in the scanner 1 will be described. The control unit 34 performs various controls of the scanner 1, including feeding, conveyance, discharging control, and reading control of the document G. A signal from an operation unit (not shown) is input to the control unit 34. The control unit 34 controls the operations of a conveyance motor 50 and a posture switching motor 40, which will be described later. In the present embodiment, each motor is a DC motor. Signals from a placement detection unit, a double feed detection unit, a document detection unit, a posture detection sensor, etc. (not shown) are also input to the control unit 34.

[0046] Next, referring to FIG. 4, the configuration in which the driving force is transmitted from the conveyance motor 50 to each roller will be described. The conveyance motor 50 is an example of a driving unit that rotates the first conveyance roller pair 16 and the second conveyance roller pair 20. The conveyance motor 50 is provided at the -X direction end in the apparatus main body 2 (FIG. 1). A driving pulley 51 is provided on the rotation shaft of the conveyance motor 50. The driving force is transmitted from the driving pulley 51 to a driven pulley 53 via a belt 52. A gear (not shown) is integrally formed on the driven pulley 53, and this gear meshes with a gear 54. A gear (not shown) is provided at the -X direction end on the shaft portion 22A of the fourth roller 22, and by this gear meshing with the gear 54, the shaft portion 22A is driven.

[0047] A gear group 58 is provided at the +X direction end with respect to the shaft portion 22A. The gear group 58 receives power from the shaft portion 22A and rotates, transmitting the driving force to the shaft portions of the respective rollers. Although a detailed description of the gear group 58 is omitted, a universal joint 59 is provided in the driving force transmission path to the first roller 17 and the driving force transmission path to the third roller 21, which is different from the driving force transmission paths to the other rollers. The universal joint 59 is provided on both sides with respect to the transmission shaft 49. Thereby, the first roller 17 and the third roller 21 are driven by the conveying motor 50 while being displaced with respect to the opposing second roller 18 and fourth roller 22.

[0048] As shown in FIG. 14, the scanner 1 includes a pressing portion 41. The pressing portion 41 can change the first pressing force acting on the document G at the first nip N1 and the second pressing force acting on the document G at the second nip N2. In other words, the first pressing force is the pressing force generated between the first roller 17 and the second roller 18. In other words, the second pressing force is the pressing force generated between the third roller 21 and the fourth roller 22.

[0049] In the following, the first pressing force may be optionally assigned any one of the symbols F1A, F1B, F1C, and F1D, and the second pressing force may be optionally assigned any one of the symbols F2A, F2B, F2C, and F2D. Also, in the following, when it is said that the two pressing forces are equal, it means that the two pressing forces are within the range of measurement error, or when an error occurs in the two pressing forces due to variations in parts or assembly errors, etc.

[0050] The pressing portion 41 changes the second pressing force F2 such that the second pressing force F2B (FIG. 13) when the first conveying roller pair 16 conveys the document G and the second conveying roller pair 20 does not convey the document G is lower than the second pressing force F2A (FIG. 12) when neither the first conveying roller pair 16 nor the second conveying roller pair 20 conveys the document G. That is, the second pressing force F2B < the second pressing force F2A.

[0051] When the first pair of conveying rollers 16 conveys the document G and the second pair of conveying rollers 20 does not convey the document G, the pressing unit 41 increases the first pressing force F1B (FIG. 13) to be greater than the first pressing force F1C (FIG. 14) when both the first pair of conveying rollers 16 and the second pair of conveying rollers 20 convey the document G. That is, the first pressing force F1B > the first pressing force F1C. When the second pair of conveying rollers 20 conveys the document G and the first pair of conveying rollers 16 does not convey the document G, the pressing unit 41 increases the second pressing force F2D (FIG. 15) to be greater than the second pressing force F2C (FIG. 14) when both the first pair of conveying rollers 16 and the second pair of conveying rollers 20 convey the document G. That is, the second pressing force F2D > the second pressing force F2C.

[0052] When both the first pair of conveying rollers 16 and the second pair of conveying rollers 20 are conveying the document G (FIG. 14), the pressing unit 41 makes the first pressing force F1C equal to the second pressing force F2C.

[0053] As shown in FIG. 5, as an example, the pressing unit 41 includes a first pressing member 42, a second pressing member 62, a shaft member 72, a spring member 76, and a spring member 77. The first pressing member 42 is an example of a first pressing unit that can change the first pressing force (FIG. 14) by changing the force acting on the shaft portion 17A of the first roller 17. The first pressing member 42 presses the central portion of the shaft portion 17A in the axial direction. The second pressing member 62 is an example of a second pressing unit that can change the second pressing force (FIG. 14) by changing the force acting on the shaft portion 21A of the third roller 21. The second pressing member 62 presses the central portion of the shaft portion 18A in the axial direction.

[0054] The shaft member 72 is an example of an interlocking unit that interlocks the first operation in which the first pressing member 42 changes the first pressing force and the second operation in which the second pressing member 62 changes the second pressing force. The spring member 76 applies a pressing force to the first pressing member 42. The spring member 77 applies a pressing force to the second pressing member 62. Hereinafter, the first pressing member 42, the second pressing member 62, the shaft member 72, the spring member 76, and the spring member 77 will be specifically described.

[0055] As shown in FIG. 6, the first pressing member 42 is connected to a part in the -A direction with respect to the center of the shaft member 72 in the A direction. The first pressing member 42 is a lever member extending in a direction intersecting both the X direction and the B direction from the shaft member 72. The first pressing member 42 has a connected portion 43, an arm portion 44, a curved surface portion 45, and an insertion portion 46. The insertion portion 46 will be described later. The connected portion 43 has a semi-circular outer shape when viewed in the +A direction. The arm portion 44 extends from the connected portion 43 toward a position in the -X direction and the -B direction. The curved surface portion 45 is formed on the lower surface in the -B direction at the tip of the arm portion 44 opposite to the connected portion 43. In other words, the curved surface portion 45 has an arc-shaped lower surface 45A protruding in the -B direction from the arm portion 44. The lower surface 45A contacts a part of the outer peripheral surface of the shaft portion 17A (FIG. 5) in the -B direction.

[0056] The second pressing member 62 is connected to a part in the +A direction with respect to the center of the shaft member 72 in the A-axis direction. The second pressing member 62 is a lever member extending in a direction intersecting both the X-axis direction and the B-axis direction from the shaft member 72. The second pressing member 62 has a connected portion 63, an arm portion 64, a curved surface portion 65, and an insertion portion (not shown). Since the arm portion 64 and the curved surface portion 65 have the same configuration as the arm portion 44 and the curved surface portion 45 as an example, a specific description thereof will be omitted. Note that the curved surface portion 65 contacts a part of the outer peripheral surface of the shaft portion 21A (FIG. 5) in the -B direction. A hole portion (not shown) penetrating the connected portion 63 in the A-axis direction is formed in the connected portion 63. A part of the shaft member 72 in the +A direction is press-fitted into the hole portion. In other words, the second pressing member 62 is rotated at the same timing as the shaft member 72.

[0057] The spring member 76 presses the first pressing member 42 in the -B direction. The spring member 77 presses the second pressing member 62 in the -B direction. Incidentally, the spring member 76 and the spring member 77 are formed symmetrically with respect to the center in the A direction as an example. For this reason, the spring member 76 will be described and the description of the spring member 77 will be omitted.

[0058] The spring member 76 is configured as a torsion spring and has a winding portion 76A, a first extending portion 76B, and a second extending portion 76C. The shaft member 72 is inserted inside the winding portion 76A. The first extending portion 76B is hooked on a part of the arm portion 44. The second extending portion 76C is engaged with a part of the apparatus main body 2 (FIG. 1). Here, when the -X direction end portion of the first pressing member 42 is rotated so as to be lifted in the +B direction, a pressing force in the -B direction, which serves as a reaction force, acts on the first pressing member 42 by the spring member 76.

[0059] The shaft member 72 is a columnar member extending in the A-axis direction. The shaft member 72 is rotatably provided in the second unit 4 (FIG. 1). A part of the +A direction of the shaft member 72 is press-fitted into a hole portion (not shown) of the second pressing member 62. In other words, the second pressing member 62 is fixed to the shaft member 72. The -A direction end portion of the shaft member 72 is notched at two locations as an example. Thereby, a first contact surface 73A and a second contact surface 73C, which are planes orthogonal to the radial direction, are formed at the end portion, respectively. In other words, when the -A direction end portion of the shaft member 72 is viewed from the -A direction to the +A direction, a first contact surface 73A, a curved surface 73B, a second contact surface 73C, and a curved surface 73D are formed. The first contact surface 73A and the second contact surface 73C are arranged substantially in parallel. Incidentally, when the shaft member 72 is viewed in the +A direction, the intersection points of the first contact surface 73A, the curved surface 73B, the second contact surface 73C, and the curved surface 73D are defined as intersection point A, intersection point B, intersection point C, and intersection point D (FIG. 7), respectively. The -A direction end portion of the shaft member 72 is inserted into the insertion portion 46 along the A-axis direction.

[0060] When the first pressing member 42 moves away from the shaft portion 17A (FIG. 5) in the +B direction and the second pressing member 62 moves away from the shaft portion 21A (FIG. 5) in the +B direction, the rotation directions of the first pressing member 42 and the second pressing member 62 are set to the +R direction. Further, when the first pressing member 42 comes into contact with the shaft portion 17A and the second pressing member 62 comes into contact with the shaft portion 21A, the rotation directions of the first pressing member 42 and the second pressing member 62 are set to the -R direction.

[0061] As shown in FIG. 7, the insertion portion 46 is a hole portion that penetrates the connected portion 43 in the A-axis direction. The inner peripheral surface 47 of the insertion portion 46 has an inner surface 47A and an inner surface 47C that are convex toward the outside in the radial direction and a first curved surface 47B and a second curved surface 47D that are convex toward the inside in the radial direction when viewed in the +A direction. The first curved surface 47B and the second curved surface 47D face each other in the X-axis direction. Also, the curvature of the first curved surface 47B and the curvature of the second curved surface 47D are in approximately the same ratio.

[0062] A state where the first pressing member 42 does not rotate relative to the shaft member 72 is referred to as a neutral state. In the neutral state of the first pressing member 42, the top of the first curved surface 47B contacts the central portion in the B-axis direction of the first contact surface 73A, and the top of the second curved surface 47D contacts the central portion in the B-axis direction of the second contact surface 73C. Also, in the neutral state of the first pressing member 42, four gap portions 48A, 48B, 48C, and 48D are provided between the first pressing member 42 and the shaft member 72 when viewed in the +A direction. The four gap portions 48A, 48B, 48C, and 48D are arranged in this order along the -R direction.

[0063] When the first pressing member 42 is rotated in the +R direction, the opening areas of the gap portion 48A and the gap portion 48C become narrower, and the opening areas of the gap portion 48B and the gap portion 48D become wider. Then, after the peripheral portion of the intersection point A comes into contact with the first curved surface 47B and the peripheral portion of the intersection point C comes into contact with the second curved surface 47D, the shaft member 72 and the first pressing member 42 rotate integrally in the +R direction.

[0064] When the first pressing member 42 rotates in the -R direction, the opening areas of the gap portions 48A and 48C expand respectively, and the opening areas of the gap portions 48B and 48D become narrower respectively. After the peripheral portion of the intersection point B comes into contact with the first curved surface 47B and the peripheral portion of the intersection point D comes into contact with the second curved surface 47D, the shaft member 72 and the first pressing member 42 rotate integrally in the -R direction.

[0065] As described above, the time point at which the shaft member 72 and the first pressing member 42 start to rotate integrally in the +R direction is shifted later with respect to the time point when the first pressing member 42 starts to rotate in the +R direction. Also, the time point at which the shaft member 72 and the first pressing member 42 start to rotate integrally in the -R direction is shifted later with respect to the time point when the first pressing member 42 starts to rotate in the -R direction. Incidentally, the second pressing member 62 (Fig. 5) always rotates integrally with the shaft member 72. In other words, the gap portions 48A, 48B, 48C, and 48D function as a so-called "play portion" that shifts the start time point of the first operation of the first pressing member 42 and the start time point of the second operation of the second pressing member 62.

[0066] As shown in Fig. 8, a correcting member 82 is provided between the feeding roller 14 and the first conveying roller pair 16 in the apparatus main body 2. The correcting member 82 is arranged to contact the central portion in the X-axis direction that intersects the +A direction of the document G fed by the feeding roller 14. The correcting member 82 is provided on the second unit 4 so as to be swingable toward the shaft portion 17A of the first roller 17. The correcting member 82 has a function of correcting the bulge of the central portion of the document G in the X-axis direction in the B-axis direction and a function of guiding the document G to the first nip N1.

[0067] As shown in Fig. 9, the correcting member 82 is configured as one member having, as an example, a bottom portion 83, arm portions 84A and 84B, shaft portions 85A and 85B, bent portions 86A and 86B, and inclined portions 87. The correcting member 82 is described in a state where the bottom portion 83 is positioned along the A-axis direction.

[0068] The bottom 83 is formed in a plate shape having a predetermined thickness in the B-axis direction and extends in the X-axis direction. The arm portion 84A is provided at the -X direction end of the bottom 83 and extends from the bottom 83 toward the positions in the -A direction and +B direction. The arm portion 84B is provided at the +X direction end of the bottom 83 and extends from the bottom 83 toward the positions in the -A direction and +B direction. The shaft portion 85A is a columnar portion extending in the +X direction from the arm portion 84A. The shaft portion 85B is a columnar portion extending in the -X direction from the arm portion 84A. The shaft portion 85A and the shaft portion 85B are rotatably supported by the second unit 4 (Fig. 8).

[0069] The bent portion 86A is provided at a position in the +A direction with respect to the arm portion 84A at the -X direction end of the bottom 83. The bent portion 86A is bent in an L shape toward the +A direction when viewed from the X direction. The bent portion 86B is provided at a position in the +A direction with respect to the arm portion 84B at the +X direction end of the bottom 83. The bent portion 86B is bent in an L shape toward the +A direction when viewed from the X direction.

[0070] The inclined portion 87 is a plate-shaped portion extending from the bottom 83 toward the positions in the -A direction and +B direction between the arm portions 84A and 84B. The inclined portion 87 is inclined with respect to the B-axis direction. The inclined portion 87 is arranged so as to be able to contact the central portion in the X-axis direction of the downstream end portion of the conveyed document G. The tip side of the inclined portion 87 is narrower in width in the X-axis direction than the base end side. A recessed portion 88 that depresses toward the base end side of the inclined portion 87 is formed at the tip portion of the inclined portion 87. Two through holes 89 that penetrate the inclined portion 87 in the thickness direction are formed at the central portion of the inclined portion 87 in the X-axis direction. Incidentally, the inclined portion 87 is pressed by a spring (not shown) toward the document G.

[0071] Next, the operation of the scanner 1 of the embodiment will be described. Regarding each configuration of the scanner 1, when referring to each configuration and each reference numeral shown in FIGS. 1 to 9, the description of individual figure numbers may be omitted.

[0072] As shown in FIG. 8, the inclined portion 87 is located upstream in the +A direction with respect to the first nip N1. A part of the bent portion 86A is in contact with the shaft portion 17A. Here, the case where a relatively thin manuscript G is fed by the feed roller 14 toward the first conveying roller pair 16 will be described.

[0073] The downstream end portion of the manuscript G in the +A direction is fed from the feed roller 14 toward the first roller 17 located in the +B direction with respect to the first nip N1. At this time, due to the fact that the feed roller 14 is located at the center in the X-axis direction, when the central portion of the manuscript G in the X-axis direction bulges in the +B direction, this bulging portion comes into contact with the inclined portion 87. As a result, the correction member 82 receives a rotational force in a direction in which the bent portion 86A moves away from the shaft portion 17A.

[0074] As shown in FIG. 10, the central portion of the manuscript G in the X-axis direction receives a reaction force from the inclined portion 87 by coming into contact with the inclined portion 87. This reaction force includes the pressing force of a spring (not shown). For this reason, the central portion of the manuscript G in the X-axis direction is suppressed from bulging in the +B direction. The manuscript G with the bulge suppressed moves in the +A direction while in contact with the inclined portion 87. That is, the manuscript G is guided to the first nip N1 by the correction member 82. Then, the manuscript G is conveyed downstream in the +A direction by the first conveying roller pair 16. Note that in FIG. 10, only the inclined portion 87 of the correction member 82 is schematically shown, and the display of other portions is omitted. The conveyance of the manuscript G after the first nip N1 will not be described.

[0075] Next, as shown in FIG. 11, the case where a thick manuscript G such as a booklet is fed and conveyed will be described. The downstream end portion of the manuscript G in the +A direction is corrected for the bulge and guided by the correction member 82 and enters the first nip N1. The manuscript G is conveyed to a reading position facing the reading unit 30 as the first conveying roller pair 16 rotates. Then, after the manuscript G is read by the reading unit 30, it enters the second nip N2. Here, with reference to FIGS. 12 to 15, the state of the pressing portion 41 (FIG. 5) will be described. Note that in FIGS. 12 to 15, each member is schematically shown. As shown in FIG. 12, before the document G enters the first nip N1, the first curved surface 47B and the first contact surface 73A are not in contact in the gap portion 48A. Further, in the gap portion 48D, the second curved surface 47D and the second contact surface 73C are not in contact. At this time, the first pressing member 42 presses the shaft portion 17A in the -B direction. The second pressing member 62 presses the shaft portion 21A in the -B direction. Before the document G enters the first nip N1, a first pressing force F1A is generated between the first roller 17 and the second roller 18. A second pressing force F2A is generated between the third roller 21 and the fourth roller 22. In this embodiment, the second pressing force F2A and the first pressing force F1A are equal. Here, the time point when the document G enters only the first nip N1 is defined as the first time point t1. Note that the illustration of the first time point t1 is omitted.

[0076] As shown in FIG. 13, when the document G enters only the first nip N1, the document G pushes up the first roller 17 in the +B direction. As a result, the first pressing force F1B becomes larger than the first pressing force F1A (FIG. 12). At this time, the shaft portion 17A rotates the first pressing member 42 in the +R direction (FIG. 7). Then, as the space in the gap portion 48A becomes smaller, the first contact surface 73A and the first curved surface 47B come into contact. As a result, the rotational force of the first pressing member 42 is transmitted to the second pressing member 62 via the shaft member 72, and the second pressing member 62 is rotated in the +R direction. For this reason, the second pressing member 62 retracts from the shaft portion 21A in the +B direction. This time point is defined as the second time point t2. Note that the illustration of the second time point t2 is omitted. At the second time point t2, the second pressing force F2B becomes smaller than the second pressing force F2A (FIG. 12). Note that the second pressing force F2B is smaller than the first pressing force F1A.

[0077] As shown in Fig. 14, when a part of the document G has entered the first nip N1 and the downstream end of the document G in the +A direction has entered the second nip N2, the document G pushes up the third roller 21 in the +B direction. At this time, the shaft portion 21A contacts the second pressing member 62 and further rotates the second pressing member 62 in the +R direction (Fig. 7). This point in time is defined as the third time point t3. Note that the illustration of the third time point t3 is omitted. At the third time point t3, the first contact surface 73A separates from the first curved surface 47B. As a result, the second pressing force F2C becomes greater than the second pressing force F2B (Fig. 13), and the first pressing force F1C becomes smaller than the first pressing force F1B (Fig. 13). Note that the second pressing force F2C is equal to the first pressing force F1C.

[0078] As shown in Fig. 15, when the document G has passed through the first nip N1 and has entered only the second nip N2, the first roller 17 moves downward in the -B direction, causing the first pressing member 42 to rotate in the -R direction (Fig. 7). Then, the space of the gap portion 48D becomes smaller, and the second contact surface 73C contacts the second curved surface 47D. This point in time is defined as the fourth time point t4. Note that the illustration of the fourth time point t4 is omitted. At the fourth time point t4, the second pressing force F2D becomes greater than the second pressing force F2C (Fig. 14), and the first pressing force F1D becomes smaller than the first pressing force F1C (Fig. 14). When the document G has passed through the second nip N2, the first pressing member 42 and the second pressing member 62 return to the same state as at time point t1. That is, the first pressing force becomes F1A, and the second pressing force becomes F2A.

[0079] As described above, according to the scanner 1, when a thick document G such as a booklet is read by the reading unit 30, the document G receives the first pressing force F1B by passing through the first nip N1 and is conveyed in the +A direction by the first conveyance roller pair 16. Then, when the document G passes through the position facing the reading unit 30, it is read by the reading unit 30. The read document G is conveyed toward the second conveyance roller pair 20. When the first pair of conveying rollers 16 conveys the original document G and the second pair of conveying rollers 20 does not convey the original document G, the pressing unit 41 changes the second pressing force so that the second pressing force F2B is lower than the second pressing force F2A when neither the first pair of conveying rollers 16 nor the second pair of conveying rollers 20 conveys the original document G. Here, when the downstream end of the read original document G in the +A direction enters between the third roller 21 and the fourth roller 22, the downstream end of the original document G tries to enter while widening the gap between the third roller 21 and the fourth roller 22. However, since the second pressing force F2B is suppressed to be lower than the second pressing force F2A, the conveying load acting on the first pair of conveying rollers 16 becomes smaller. As a result, a decrease in the conveying speed of the original document G by the first pair of conveying rollers 16 is suppressed. Thus, since a decrease in the conveying speed of the original document G in the first pair of conveying rollers 16 is suppressed, a decrease in the reading quality of the original document G in the reading unit 30 can be suppressed.

[0080] In particular, in a configuration where both the third roller 21 and the fourth roller 22 are driven by the conveying motor 50, when the downstream end of the original document G abuts on the circumferential surface of the third roller 21, the downstream end of the original document G is likely to receive a large resistance from the third roller 21. Furthermore, when the third roller 21 rotates at a speed lower than the planned speed, such a problem is likely to become prominent. However, as described above, since the second pressing force F2B is suppressed to be lower than the second pressing force F2A, the conveying load acting on the first pair of conveying rollers 16 when the downstream end of the original document G enters the second pair of conveying rollers 20 can be suppressed.

[0081] According to the scanner 1, when only the first pair of conveying rollers 16 or only the second pair of conveying rollers 20 conveys the original document G, the pressing force on the original document G is increased. As a result, slipping of the first pair of conveying rollers 16 or the second pair of conveying rollers 20 with respect to the original document G is suppressed, so that the conveying state of the original document G can be stabilized.

[0082] According to the scanner 1, by the interlocking of the first operation of the first pressing member 42 and the second operation of the second pressing member 62, the first pressing force and the second pressing force are changed. Thereby, compared with a configuration in which the mechanism for changing the first pressing force and the mechanism for changing the second pressing force are driven independently, the configuration for changing the first pressing force and the second pressing force can be made simpler.

[0083] As a comparative example, in the configuration where the first pressing member 42 and the second pressing member 62 are integrated, when the first pressing member 42 is slightly displaced, the second pressing member 62 will also be displaced almost simultaneously. Similarly, when the second pressing member 62 is slightly displaced, the first pressing member 42 will also be displaced almost simultaneously. Thus, in the configuration where the first pressing member 42 and the second pressing member 62 are integrated, fluctuations in the pressing force are likely to occur in each of the first pressing member 42 and the second pressing member 62. On the other hand, according to the scanner 1 of the present embodiment, although the first operation and the second operation are interlocked, due to the gap portions 48A, 48B, 48C, 48D, the start timing of the first operation and the start timing of the second operation are shifted. Thereby, even if one of the first pressing member 42 and the second pressing member 62 is slightly displaced, the other is suppressed from being displaced simultaneously, so that fluctuations in the first pressing force and the second pressing force can be suppressed.

[0084] According to the scanner 1, since the pressing portions of the shaft portion 17A and the shaft portion 21A are aligned at the central portion in the X-axis direction, the loads acting in the X-axis direction can be made uniform in each of the shaft portion 17A and the shaft portion 21A. According to the scanner 1, by the correcting member 82 contacting the central portion of the document G in the X-axis direction, it is possible to suppress the central portion of the document G from rising in a direction away from the conveyance path R of the document G. Thereby, conveyance failures such as wrinkles and jams of the document G when feeding the document G to the first conveyance roller pair 16 can be suppressed. According to the scanner 1, when the document G contacts the correcting member 82, it is guided to the first nip N1 as it is conveyed. Thereby, compared with a configuration without the correcting member 82, the document G is more likely to enter the first nip N1.

[0085] According to the scanner 1, when a thin original document G is fed to the first pair of conveyance rollers 16, since a part of the thin original document G is lifted in a direction away from the conveyance path R by contacting the correction member 82, it is possible to suppress such lifting. Note that since the reaction force exerted by the thin original document G on the correction member 82 is small, the amount of swing of the correction member 82 is small. Furthermore, when a thick original document G is fed to the first pair of conveyance rollers 16, the reaction force exerted by the thick original document G on the correction member 82 is large. For this reason, the correction member 82 is swung toward the shaft portion 17A. In other words, the correction member 82 is retracted from the conveyance path R of the original document G. Thereby, since an increase in the reaction force acting on the original document G being conveyed from the correction member 82 is suppressed, it is possible to suppress the conveyance load on the conveyance roller 14 when feeding the thick original document G.

[0086] The scanner 1 according to the embodiment of the present invention is basically configured as described above, but it is of course possible to make partial configuration changes, omissions, combinations, etc. within a range not departing from the gist of the present invention. In the scanner 1, the attitude of the apparatus main body 2 with respect to the stand 6 is switched by the power of the attitude switching motor 40, but instead of this, or in addition to this, it may be configured to switch the attitude of the apparatus main body 2 by a manual operation of the user.

[0087] In the scanner 1, the first pressing force F1B when the first pair of conveyance rollers 16 conveys the original document G and the second pair of conveyance rollers 20 does not convey the original document G does not necessarily have to be made larger than the first pressing force F1C when the first pair of conveyance rollers 16 and the second pair of conveyance rollers 20 convey the original document G. For example, the first pressing force F1B and the first pressing force F1C may be made equal. The second pressing force F2D when the second pair of conveyance rollers 20 conveys the original document G and the first pair of conveyance rollers 16 does not convey the original document G does not necessarily have to be made larger than the second pressing force F2C when the first pair of conveyance rollers 16 and the second pair of conveyance rollers 20 convey the original document G. For example, the second pressing force F2D and the second pressing force F2C may be made equal.

[0088] When the first pair of conveying rollers 16 and the second pair of conveying rollers 20 are both conveying the document G, the pressing unit 41 does not necessarily have to make the first pressing force F1C equal to the second pressing force F2C. For example, when the first pair of conveying rollers 16 and the second pair of conveying rollers 20 are both conveying the document G, the first pressing force F1C may be greater than the second pressing force F2C, or the first pressing force F1C may be smaller than the second pressing force F2C. Also, when the first pair of conveying rollers 16 and the second pair of conveying rollers 20 are not both conveying the document G, the first pressing force F1A may be greater than the second pressing force F2A, or the first pressing force F1A may be smaller than the second pressing force F2A. The pressing unit 41 does not necessarily have to include the shaft member 72. In other words, the pressing unit 41 does not necessarily have to interlock the first operation in which the first pressing member 42 changes the first pressing force F1 and the second operation in which the second pressing member 62 changes the second pressing force F2.

[0089] The sizes of the gap portions 48A, 48B, 48C, and 48D can be appropriately changed. For example, the sizes of the gaps of the gap portions 48B and 48D may be made larger than those of the gap portions 48A and 48C. That is, when the pressing unit 41 is in a state where the document G has passed through the first nip N1 and entered the second nip N2, a predetermined first pressing force may be generated on the first pair of conveying rollers 16. Also, when conveying a booklet, when the downstream end portion side of the booklet has passed through the first nip N1 and entered the second nip N2, the upstream end portion side of the booklet may be pressed with a predetermined first pressing force. When conveying a booklet such as a passport, the thickness may be different between the +A direction side and the -A direction side with respect to the center portion of the booklet. When the thickness of the +A direction side of the booklet is thicker than the thickness of the -A direction side of the booklet, in a state where the +A direction side of the booklet has passed through the first nip N1 and entered the second nip N2 and the -A direction side of the booklet has entered the first nip N1, the first pressing force by the first pair of conveying rollers 16 may become smaller. As a result, the first pair of conveying rollers 16 may not be able to appropriately nip the -A direction side of the booklet, and there is a possibility that the conveying speed of the booklet may change while the reading unit 30 is reading the booklet. However, in a state where the +A direction side (the thicker side) of the booklet passes through the first nip N1 and enters the second nip N2, and the -A direction side (the thinner side) of the booklet enters the first nip N1, the -A direction side of the booklet is pressed by the first conveying roller pair 16 with a predetermined first pressing force, so that a change in the conveying speed of the booklet can be suppressed.

[0090] The gap portions 48A, 48B, 48C, and 48D may be provided in the second pressing member 62, and the first pressing member 42 may be fixed to the shaft member 72. The first pressing member 42 may have a branched structure and press one part and the other part with respect to the center in the axial direction of the shaft portion 17A, respectively. The second pressing member 62 may have a branched structure and press one part and the other part with respect to the center in the axial direction of the shaft portion 21A, respectively.

[0091] In the scanner 1, the correction member 82 may not be provided. The correction member 82 may only correct the swelling of the document G. That is, the correction member 82 may not guide the document G to the first nip N1. The correction member 82 is not limited to a swinging one, and may be, for example, a member that slides in the B-axis direction.

Explanation of Reference Numerals

[0092] 1... Scanner, 2... Apparatus main body, 3... First unit, 4... Second unit, 5... Third unit, 6... Stand, 6A... Main body rotation axis, 10... Upper opening / closing part, 11... Document support part, 12... Edge guide, 14... Feeding roller, 15... Separation roller, 16... First conveying roller pair, 17... First roller, 17A... Shaft part, 17B... Roller part, 18... Second roller, 18A... Shaft part, 18B... Roller part, 19... Feeding port, 20... Second conveying roller pair, 21... Third roller, 21A... Shaft part, 21B... Roller part, 22... Fourth roller, 22A... Shaft part, 22B... Roller part, 23... Bearing member, 24…Third conveying roller pair, 27…Bearing member, 28…Fourth conveying roller pair, 30…Reading unit, 32…First reading unit, 32A…Contact glass, 33…Second reading unit, 33A…Contact glass, 34…Control unit, 35…Flap, 37…First discharge port, 38…Second discharge port, 40…Posture switching motor, 41…Pressing part, 42…First pressing member, 43…Connected part, 44…Arm part, 45…Curved surface part, 45A…Lower surface, 46…Insertion part, 47…Inner peripheral surface, 47A…Inner surface, 47B…First curved surface, 47C…Inner surface, 47D…Second curved surface, 48A…Gap part, 48B…Gap part, 48C…Gap part, 48D…Gap part, 49…Transmission shaft, 50…Conveying motor, 51…Drive pulley, 52…Belt, 53…Driven pulley, 54…Gear, 58…Gear group, 59…Universal joint, 62…Second pressing member, 63…Connected part, 64…Arm part, 65…Curved surface part, 72…Shaft member, 73A…First contact surface, 73B…Curved surface, 73C…Second contact surface, 73D…Curved surface, 76…Spring member, 76A…Wound part, 76B…First extending part, 76C…Second extending part, 77…Spring member, 82…Correction member, 83…Bottom part, 84A…Arm part, 84B…Arm part, 85A…Shaft part, 85B…Shaft part, 86A…Bending part, 86B…Bending part, 87…Inclined part, 88…Depressed part, 89…Through hole, D…Placement surface, F1…First pressing force, F2…Second pressing force, F2A…Second pressing force, F2B…Second pressing force, G…Original document, GA…First side, GB…Second side, N1…First nip, N2…Second nip, R…Conveying path, R1…Original document feeding path, R2…Reading and conveying path, R3…Reverse conveying path, R4…Non-reverse conveying path

Claims

1. A first pair of conveying rollers having a first roller and a second roller, the first pair of conveying rollers for conveying while pressing a document, A reading unit for reading the document conveyed by the first pair of conveying rollers, A second pair of conveying rollers having a third roller and a fourth roller, the second pair of conveying rollers being located downstream of the reading unit in the conveying direction of the document and conveying the document while pressing the document, A driving unit for applying power to the first roller, the second roller, the third roller, and the fourth roller, A pressing unit capable of changing a first pressing force generated between the first roller and the second roller and a second pressing force generated between the third roller and the fourth roller, Comprising, When the first pair of conveying rollers is conveying the document and the second pair of conveying rollers is not conveying the document, the pressing unit changes the second pressing force so that the second pressing force is lower than the second pressing force when neither the first pair of conveying rollers nor the second pair of conveying rollers is conveying the document, When the first pair of conveying rollers and the second pair of conveying rollers are both conveying the document, the pressing unit makes the first pressing force and the second pressing force equal, An image reading apparatus characterized by the above.

2. A first pair of conveying rollers having a first roller and a second roller, the first pair of conveying rollers for conveying while pressing a document, A reading unit for reading the document conveyed by the first pair of conveying rollers, A second pair of conveying rollers having a third roller and a fourth roller, the second pair of conveying rollers being located downstream of the reading unit in the conveying direction of the document and conveying the document while pressing the document, A driving unit for applying power to the first roller, the second roller, the third roller, and the fourth roller, A pressing unit capable of changing a first pressing force generated between the first roller and the second roller and a second pressing force generated between the third roller and the fourth roller, Comprising, When the first pair of conveying rollers is conveying the document and the second pair of conveying rollers is not conveying the document, the pressing unit changes the second pressing force so that the second pressing force is lower than the second pressing force when neither the first pair of conveying rollers nor the second pair of conveying rollers is conveying the document, The pressing unit is, A first pressing part capable of changing the first pressing force by changing the force acting on the first rotation axis of the first roller; A second pressing part capable of changing the second pressing force by changing the force acting on the second rotation axis of the third roller; An interlocking part that interlocks a first operation in which the first pressing part changes the first pressing force and a second operation in which the second pressing part changes the second pressing force; Comprising; An image reading apparatus characterized by the above.

3. In the image reading apparatus according to claim 2, The interlocking part is a shaft member provided rotatably, One of the first pressing part and the second pressing part is fixed to the shaft member, A gap part that shifts the start time of the first operation and the start time of the second operation is provided between the other of the first pressing part and the second pressing part and the shaft member. An image reading apparatus characterized by the above.

4. In the image reading apparatus according to claim 2 or claim 3, A plurality of the first rollers are provided on the first rotation axis, and a plurality of the third rollers are provided on the second rotation axis. The first pressing part presses between the first rollers on the first rotation axis. The second pressing part presses between the third rollers on the second rotation axis. An image reading apparatus characterized by the above.

5. A first pair of conveying rollers having a first roller and a second roller, the first pair of conveying rollers that convey while pressing a document; A reading part that reads the document conveyed by the first pair of conveying rollers; A second pair of conveying rollers having a third roller and a fourth roller, the second pair of conveying rollers that are located downstream of the reading part in the conveying direction of the document and convey while pressing the document; A driving part that applies power to the first roller, the second roller, the third roller, and the fourth roller; A pressing part capable of changing a first pressing force generated between the first roller and the second roller and a second pressing force generated between the third roller and the fourth roller; Comprising; When the first pair of conveying rollers convey the document and the second pair of conveying rollers do not convey the document, the pressing part changes the second pressing force so that the second pressing force is lower than the second pressing force when neither the first pair of conveying rollers nor the second pair of conveying rollers convey the document. A plurality of the first pair of conveying rollers are provided in a width direction intersecting the conveying direction. A feeding roller provided upstream of the first pair of conveying rollers in the conveying direction for feeding the document to the first pair of conveying rollers; A correcting member provided between the feeding roller and the first pair of conveying rollers and contacting the document; The correcting member contacts between the first pair of conveying rollers of the document fed by the feeding roller; An image reading apparatus characterized by the above.

6. In the image reading apparatus according to claim 5, The correcting member guides the document to the nip between the first roller and the second roller; An image reading apparatus characterized by the above.

7. In the image reading apparatus according to claim 5 or claim 6, The correcting member is provided so as to be swingable toward the first rotation axis of the first roller; An image reading apparatus characterized by the above.

8. In the image reading apparatus according to any one of claims 1 to 7, The pressing portion When the first pair of conveying rollers convey the document and the second pair of conveying rollers do not convey the document, increases the first pressing force compared to the case where the first pair of conveying rollers and the second pair of conveying rollers convey the document; When the second pair of conveying rollers convey the document and the first pair of conveying rollers do not convey the document, increases the second pressing force compared to the case where the first pair of conveying rollers and the second pair of conveying rollers convey the document; An image reading apparatus characterized by the above.

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