Medium conveying device

Abstract

To provide a medium conveying device that enables rollers for assisting the conveyance of a medium to be favorably mounted on a mounting base.SOLUTION: There is provided a medium conveying device capable of conveying a medium well. The medium conveying device includes: a motor that generates driving force; a first shaft that extends linearly in a direction perpendicular to a medium conveying direction and is arranged to rotate according to the driving force; a conveying roller that is fixed to the first shaft and conveys the medium; a second shaft; a driven roller that is rotatably arranged on the second shaft and rotates following the conveying roller; and a pressing portion that presses a central portion of the second shaft in a direction perpendicular to the medium conveying direction toward a downstream side in the medium conveying direction.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] TECHNICAL FIELD The present disclosure relates to a media transport device, and more particularly to a media transport device having a transport roller and a driven roller. [Background technology]

[0002] In general, a medium transport device such as a scanner captures an image of a medium transported by a transport roller to generate an image. In such a medium transport device, if wrinkles occur in the transported medium, noise may be included in the image of the medium.

[0003] An original transport device is disclosed that includes two or more original transport rollers that transport an original, and two or more driven rollers that face the original transport rollers (see Patent Document 1). In this original transport device, a bearing that rotatably supports the original transport roller shaft at the axial center of the original transport roller shaft that supports the original transport rollers is provided downstream in the original transport direction from a bearing that rotatably supports the original transport roller shaft at an end of the original transport roller shaft. The original transport roller shaft is formed of a single original transport roller shaft, and is rotatably supported by a third bearing in a state curved toward the downstream side in the original transport direction.

[0004] A medium transport device is disclosed that includes a drive roller that is rotationally driven to transport a medium, and a driven roller that rotates while nipping the medium between the drive roller (see Patent Document 2). This medium transport device includes pressing members that are disposed on one shaft end side and the other shaft end side of the rotation shaft of the driven roller and press the rotation shaft in the direction in which the driven roller comes into contact with the drive roller, and a spacer that is interposed between the rotation shaft and the pressing members. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4024486 [Patent Document 2] JP 2019-64762 A Summary of the Invention

[0006] A medium transport device is required to transport a medium in an excellent manner.

[0007] The purpose of the media transport device is to enable good transport of the media.

[0008] A media transport device according to one aspect of an embodiment includes a motor that generates a driving force, a first shaft that extends linearly in a direction perpendicular to the media transport direction and is arranged to rotate in accordance with the driving force, a transport roller fixed to the first shaft and transports the media, a second shaft, a driven roller that is rotatably arranged on the second shaft and rotates in response to the transport roller, and a pressing portion that presses the center portion of the second shaft in a direction perpendicular to the media transport direction toward the downstream side of the media transport direction.

[0009] Moreover, a media transport device according to one aspect of the embodiment includes a motor that generates a driving force, a first shaft that extends linearly in a direction perpendicular to the media transport direction and is arranged to rotate in accordance with the driving force, a transport roller that is fixed to the first shaft and transports the media, a second shaft that is inclined so that its central portion in the direction perpendicular to the media transport direction is located downstream in the media transport direction than the end portions, and a driven roller that is rotatably arranged on the second shaft and rotates in conjunction with the transport roller.

[0010] According to this embodiment, the medium transport device is able to transport the medium well.

[0011] The objects and advantages of the invention will be realized and obtained by means of the elements and combinations particularly pointed out in the claims. Both the foregoing general description and the following detailed description are exemplary and explanatory but are not restrictive of the invention as claimed. [Brief description of the drawings]

[0012] [Figure 1]1 is a perspective view showing a medium conveying device 100 according to an embodiment. [Diagram 2] 2 is a diagram for explaining a transport path inside the medium transport device 100. FIG. [Diagram 3] 1 is a schematic diagram for explaining a transport mechanism 130. FIG. [Figure 4] 10 is a schematic diagram for explaining a first driven roller 117 and the like. FIG. [Diagram 5] 10 is a schematic diagram for explaining a first driven roller 117 and the like. FIG. [Figure 6] 11 is a schematic diagram for explaining a first pressing member 133. FIG. [Figure 7] 13(A) and 13(B) are schematic diagrams for explaining a first pressing member 133. FIG. [Figure 8] 10 is a schematic diagram for explaining the operation of the transport mechanism 130. FIG. [Figure 9] 10 is a schematic diagram for explaining the operation of the transport mechanism 130. FIG. [Figure 10] 1 is a block diagram showing a schematic configuration of a medium conveying device 100. FIG. [Figure 11] FIG. 2 is a diagram showing a schematic configuration of a storage device 150 and a processing circuit 160. [Figure 12] 10 is a flowchart illustrating an example of the operation of a medium reading process. [Figure 13] 13(A) and 13(B) are schematic diagrams for explaining another first pressing member 233. FIG. [Figure 14] 10 is a flowchart showing an example of the operation of another medium reading process. [Figure 15] 13(A) and 13(B) are schematic diagrams for explaining another first pressing member 333. FIG. [Figure 16] 13(A) and 13(B) are schematic diagrams for explaining another first pressing member 333. FIG. [Figure 17] 13 is a schematic diagram for explaining another supporting member 437. FIG. [Figure 18] 13 is a schematic diagram for explaining another transport mechanism 530. FIG. [Figure 19]13 is a schematic diagram for explaining another transport mechanism 530. FIG. [Figure 20] 13 is a schematic diagram for explaining another transport mechanism 630. FIG. [Figure 21] 13 is a schematic diagram for explaining another transport mechanism 730. FIG. [Figure 22] 13 is a schematic diagram for explaining another transport mechanism 730. FIG. [Diagram 23] FIG. 13 is a diagram showing a schematic configuration of another processing circuit 860. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a medium conveying device, a control method, and a control program according to one aspect of the present disclosure will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiments, but extends to the inventions described in the claims and their equivalents.

[0014] 1 is a perspective view showing a medium conveying device 100 configured as an image scanner. The medium conveying device 100 conveys a medium, which is an original document, and captures an image of the medium. The medium is paper, thin paper, thick paper, a card, an envelope, or the like. The medium conveying device 100 may be a facsimile, a copier, a multifunction printer (MFP, Multifunction Peripheral), or the like. Note that the medium being conveyed may not be an original document, but may be a print target, or the like, and the medium conveying device 100 may be a printer, or the like.

[0015] The medium conveying device 100 includes a lower housing 101, an upper housing 102, a loading stand 103, an ejection stand 104, an operation device 105, and a display device 106. In Fig. 1, an arrow A1 indicates the medium conveying direction, an arrow A2 indicates the width direction perpendicular to the medium conveying direction, and an arrow A3 indicates the height direction perpendicular to the medium conveying surface. In the following, upstream refers to the upstream side of the medium conveying direction A1, and downstream refers to the downstream side of the medium conveying direction A1.

[0016] The upper housing 102 is positioned to cover the top surface of the medium conveying device 100, and is rotatably engaged with the lower housing 101 by a hinge H so that it can be opened and closed when a medium is jammed, when the inside of the medium conveying device 100 is cleaned, etc.

[0017] The placement stage 103 engages with the lower housing 101 and places thereon the media to be fed and transported. The ejection stage 104 engages with the upper housing 102 and places thereon the ejected media. Note that the ejection stage 104 may also engage with the lower housing 101.

[0018] The operation device 105 has an input device such as a button and an interface circuit for acquiring a signal from the input device, accepts an input operation by a user, and outputs an operation signal according to the input operation by the user. The display device 106 has a display including a liquid crystal, an organic EL (Electro-Luminescence), or the like, and an interface circuit for outputting image data to the display, and displays the image data on the display.

[0019] FIG. 2 is a diagram for explaining a transport path inside the medium transport device 100. As shown in FIG.

[0020] The transport path inside the media transport device 100 includes a first media sensor 111, a feed roller 112, a separation roller 113, an ultrasonic sensor 114, a second media sensor 115, a first transport roller 116, a first driven roller 117, an imaging device 118, a second transport roller 119, and a second driven roller 120, etc.

[0021] The number of each of the feed roller 112, separation roller 113, first conveyor roller 116, first driven roller 117, second conveyor roller 119, and / or second driven roller 120 is not limited to one, and may be more than one. In this case, the multiple feed rollers 112, separation rollers 113, first conveyor roller 116, first driven roller 117, second conveyor roller 119, and / or second driven roller 120 are arranged at intervals in the width direction A2.

[0022] The top surface of the lower housing 101 forms a lower guide 101a of the medium transport path, and the bottom surface of the upper housing 102 forms an upper guide 102a of the medium transport path. The lower guide 101a forms a medium transport surface.

[0023] The first medium sensor 111 is disposed upstream of the feed roller 112 and the separation roller 113. The first medium sensor 111 has a contact detection sensor and detects whether or not a medium is placed on the placement table 103. The first medium sensor 111 generates and outputs a first medium signal whose signal value changes depending on whether or not a medium is placed on the placement table 103. Note that the first medium sensor 111 is not limited to a contact detection sensor, and any other sensor capable of detecting the presence or absence of a medium, such as a light detection sensor, may be used as the first medium sensor 111.

[0024] The feed roller 112 is provided in the lower housing 101, and separates and feeds the media placed on the mounting table 103 from the bottom. The separation roller 113 is a so-called brake roller or retard roller, and is provided in the upper housing 102, disposed opposite the feed roller 112, and rotates in the opposite direction to the medium feeding direction. Note that the feed roller 112 may be provided in the upper housing 102 and the separation roller 113 in the lower housing 101, and the feed roller 112 may feed the media placed on the mounting table 103 from the top.

[0025] The ultrasonic sensor 114 is disposed downstream of the feed roller 112 and the separation roller 113 and upstream of the first conveyor roller 116 and the first driven roller 117. The ultrasonic sensor 114 includes an ultrasonic transmitter 114a and an ultrasonic receiver 114b. The ultrasonic transmitter 114a and the ultrasonic receiver 114b are disposed in the upper housing 102 and the lower housing 101, respectively, near the conveyance path of the medium, facing each other across the conveyance path. The ultrasonic transmitter 114a emits ultrasonic waves. On the other hand, the ultrasonic receiver 114b receives ultrasonic waves emitted by the ultrasonic transmitter 114a and passing through the medium, and generates and outputs an ultrasonic signal, which is an electrical signal corresponding to the received ultrasonic waves. Note that the ultrasonic transmitter 114a may be disposed in the lower housing 101, and the ultrasonic receiver 114b may be disposed in the upper housing 102.

[0026] The second medium sensor 115 is disposed downstream of the feed roller 112 and the separation roller 113 and upstream of the first transport roller 116 and the first driven roller 117, and detects a medium transported to that position. The second medium sensor 115 includes a light emitter and a light receiver provided on one side of the medium transport path, and a light guide tube provided at a position facing the light emitter and the light receiver across the medium transport path. The light emitter is an LED (Light Emitting Diode) or the like, and emits light toward the medium transport path. On the other hand, the light receiver receives the light emitted by the light emitter and guided by the light guide tube. When a medium is present at a position facing the second medium sensor 115, the light emitted from the light emitter is blocked by the medium, so the light receiver does not detect the light emitted from the light emitter. The light receiver generates and outputs a second medium signal whose signal value changes depending on whether a medium is present or not at the position of the second medium sensor 115 based on the intensity of the light received.

[0027] A reflective member such as a mirror may be used instead of the light guide tube. The light emitter and the light receiver may be provided facing each other across the medium transport path. The second medium sensor 115 may detect the presence of the medium using a contact detection sensor that passes a predetermined current when the medium is in contact or when the medium is not in contact.

[0028] The first conveying roller 116 and the first driven roller 117 are an example of a conveying roller and a driven roller, respectively, and are disposed facing each other downstream of the feed roller 112. The first conveying roller 116 is provided in the upper housing 102, and conveys the medium fed by the feed roller 112 and the separation roller 113 to the imaging device 118. The first driven roller 117 is provided in the lower housing 101 below the first conveying roller 116, and rotates following the first conveying roller 116.

[0029] The imaging device 118 is disposed downstream of the first conveying roller 116 and captures an image of the medium conveyed by the first conveying roller 116. The imaging device 118 includes a first imaging device 118a and a second imaging device 118b disposed opposite each other across the medium conveying path. The first imaging device 118a has a line sensor based on a CIS (Contact Image Sensor) of a life-size optical system type having imaging elements based on CMOS (Complementary Metal Oxide Semiconductor) linearly arranged in the main scanning direction. The first imaging device 118a also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The first imaging device 118a captures an image of the surface of the medium being conveyed, generates an input image, and outputs it, according to control from a processing circuit described later.

[0030] Similarly, the second imaging device 118b has a line sensor using a CIS of a life-size optical system type having CMOS imaging elements arranged in a line in the main scanning direction. The second imaging device 118b also has a lens that forms an image on the imaging element, and an A / D converter that amplifies and analog-to-digital (A / D) converts the electrical signal output from the imaging element. The second imaging device 118b captures the back side of the medium being conveyed under the control of a processing circuit described later, generates an input image, and outputs it.

[0031] The medium conveying device 100 may have only one of the first imaging device 118a and the second imaging device 118b arranged to read only one side of the medium. Also, instead of a CIS line sensor of an equal magnification optical system type having a CMOS imaging element, a CIS line sensor of an equal magnification optical system type having a CCD (Charge Coupled Device) imaging element may be used. Also, a reduction optical system type line sensor having a CMOS or CCD imaging element may be used.

[0032] The second conveying roller 119 and the second driven roller 120 are disposed facing each other downstream of the imaging device 118. The second conveying roller 119 is provided in the upper housing 102, and discharges the medium conveyed by the first conveying roller 116 and the first driven roller 117 and imaged by the imaging device 118 to the discharge tray 104. The second driven roller 120 is provided in the lower housing 101 below the second conveying roller 119, and rotates while being driven by the second conveying roller 119.

[0033] 2, i.e., the medium feeding direction, the medium placed on the placement table 103 is transported between the lower guide 101a and the upper guide 102a in the medium transport direction A1. When feeding the medium, the separation roller 113 rotates in the direction of the arrow A5, i.e., the opposite direction to the medium feeding direction. When multiple media are placed on the placement table 103, the feed roller 112 and the separation roller 113 function to separate only the media placed on the placement table 103 that is in contact with the feed roller 112. This limits the transport of media other than the separated media (preventing double feeding).

[0034] The medium is fed between first conveyor roller 116 and first driven roller 117 while being guided by lower guide 101a and upper guide 102a. The medium is fed between first imaging device 118a and second imaging device 118b as first conveyor roller 116 rotates in the direction of arrow A6. The medium read by imaging device 118 is discharged onto discharge tray 104 as second conveyor roller 119 rotates in the direction of arrow A7.

[0035] FIG. 3 is a perspective view for explaining the transport mechanism 130 of the medium transport device 100. As shown in FIG.

[0036] 3, the conveying mechanism 130 has a first shaft 131, a second shaft 132, a first pressing member 133, a third shaft 134, a fourth shaft 135, a second pressing member 136, etc., in addition to a first conveying roller 116, a first driven roller 117, a second conveying roller 119, and a second driven roller 120. In the example shown in Fig. 3, two each of the first conveying roller 116, the first driven roller 117, the second conveying roller 119, and the second driven roller 120 are arranged.

[0037] The first shaft 131 extends straight in a linear manner in a width direction A2 perpendicular to the medium transport direction, and is provided so as to rotate in accordance with a driving force generated by a motor described later. The first transport roller 116 is fixed to the first shaft 131 so as to rotate in accordance with the rotation of the first shaft 131.

[0038] The second shaft 132 is disposed to face the first shaft 131 and extend substantially parallel to the width direction A2 perpendicular to the medium transport direction. The first driven roller 117 is disposed on the second shaft 132 so as to be rotatable along a direction perpendicular to the extension direction of the second shaft 132.

[0039] The first pressing member 133 is an example of a pressing section, and is disposed between the two first driven rollers 117, i.e., at the center of the width direction A2 perpendicular to the medium conveying direction, so as to abut against the second shaft 132. In particular, it is preferable that the first pressing member 133 is disposed at the center of the arrangement positions of the first driven rollers 117 in the width direction A2. As a result, the two first driven rollers 117 are disposed line-symmetrically with the first pressing member 133 in between, and the pressing force with which each first driven roller 117 presses each first conveying roller 116 becomes uniform, so that the medium conveying device 100 can suppress the occurrence of skew of the medium. The first pressing member 133 is disposed so as to abut against the lower side of the second shaft 132 so as to press the second shaft 132 toward the first shaft 131, i.e., upward.

[0040] The third shaft 134 extends straight in a linear manner in the width direction A2 perpendicular to the medium transport direction, and is provided so as to rotate in accordance with a driving force generated by a motor described later. The second transport roller 119 is fixed to the third shaft 134 so as to rotate in accordance with the rotation of the third shaft 134.

[0041] The fourth shaft 135 faces the third shaft 134 and is provided so as to extend linearly in a width direction A2 perpendicular to the medium transport direction. The second driven roller 120 is provided on the fourth shaft 135 so as to be rotatable along a direction perpendicular to the extension direction of the fourth shaft 135.

[0042] The second pressing member 136 is an example of a second pressing portion, and is disposed between the two second driven rollers 120, i.e., at the center of the width direction A2 perpendicular to the medium conveying direction, so as to abut against the fourth shaft 135. In particular, it is preferable that the second pressing member 136 is disposed at the center of the arrangement positions of the second driven rollers 120 in the width direction A2. As a result, the two second driven rollers 120 are disposed line-symmetrically with respect to the second pressing member 136, and the pressing force with which each second driven roller 120 presses each second conveying roller 119 becomes uniform, so that the medium conveying device 100 can suppress the occurrence of skew of the medium. The second pressing member 136 is disposed so as to abut against the lower side of the fourth shaft 135 so as to press the fourth shaft 135 toward the third shaft 134, i.e., upward.

[0043] Figures 4 and 5 are schematic diagrams for explaining the first driven roller 117 and the second shaft 132. Figure 4 is a perspective view of the first driven roller 117 and the second shaft 132, and Figure 5 is a schematic diagram of the first driven roller 117 and the second shaft 132 as viewed from the side.

[0044] As shown in FIG. 4 and FIG. 5, the medium conveying device 100 further includes a support member 137. The support member 137 is formed of a resin member or a metal member, and is provided so as to support the second shaft 132 on the outer side of the two first driven rollers 117, that is, at the end of the second shaft 132 in the width direction A2 perpendicular to the medium conveying direction. The support member 137 is provided with a cutout portion (or an opening) into which the end of the second shaft 132 in the width direction A2 is inserted. The cutout portion (or the opening) is provided with a support surface 137a formed in a flat shape. Meanwhile, the end of the second shaft 132 in the width direction A2 is provided with a supported surface 132a with a D cut. The support surface 137a and the supported surface 132a are abutted against each other, so that the second shaft 132 is fixed by the support member 137 and is provided so as not to rotate. Meanwhile, the first driven roller 117 is provided so as to be rotatable relative to the second shaft 132.

[0045] Since the first driven roller 117 is rotatably arranged relative to the second shaft 132, the second driven roller 120 rotates smoothly in conjunction with the first conveying roller 116 even when the central portion of the second shaft 132 in the width direction A2 is pressed downstream, as described below.

[0046] 6, 7(A) and 7(B) are schematic diagrams for explaining the first pressing member 133. Fig. 6 is a perspective view of the first pressing member 133 in a state in which the second shaft 132 is placed thereon, Fig. 7(A) is a perspective view of the first pressing member 133 in a state in which the second shaft 132 is not placed thereon, and Fig. 7(B) is a schematic diagram of the first pressing member 133 as viewed from the side.

[0047] As shown in FIG. 6 and FIG. 7(A) and (B), the first pressing member 133 has a first contact surface 133a. The first contact surface 133a contacts the second shaft 132 and presses the second shaft 132. The first contact surface 133a is an example of an inclined surface, and is formed so as to be inclined with respect to a medium transport surface parallel to the medium transport direction A1 and the width direction A2, particularly so as to be inclined downward toward the downstream side. That is, the first pressing member 133 is provided so as to press the center part of the second shaft 132 in the width direction A2 perpendicular to the medium transport direction toward the downstream side of the medium transport direction A1 when pressing the second shaft 132 from below along the height direction A3 perpendicular to the medium transport surface.

[0048] Fig. 8 is a schematic diagram for explaining the operation of the transport mechanism 130. Fig. 8 is a schematic diagram of the transport mechanism 130 as viewed from the side.

[0049] As described above, the second shaft 132 is provided so as to face the first shaft 131, and the fourth shaft 135 is provided so as to face the third shaft 134. However, as shown in FIG. 8, the second shaft 132 is provided on the upstream side of the first shaft 131. As a result, the first driven roller 117 provided below the first conveyor roller 116 is provided on the upstream side of the first conveyor roller 116. Therefore, the nip surface between the first conveyor roller 116 and the first driven roller 117 is inclined so as to face downward toward the downstream side. On the other hand, the fourth shaft 135 is provided on the downstream side of the third shaft 134. As a result, the second driven roller 120 provided below the second conveyor roller 119 is provided on the downstream side of the second conveyor roller 119. Therefore, the nip surface between the second conveyor roller 119 and the second driven roller 120 is inclined so as to face upward toward the downstream side.

[0050] In Fig. 8, path R indicates a path along which the leading edge of a medium ideally passes when being transported. Since the nip surface between the first transport roller 116 and the first driven roller 117 is inclined so as to face downward toward the downstream side, the leading edge of the medium transported by the first transport roller 116 and the first driven roller 117 is transported so as to face downward. The leading edge of the medium comes into contact with the glass surface G of the first imaging device 118a and is transported along the glass surface G. Since the nip surface between the second transport roller 119 and the second driven roller 120 is inclined so as to face upward toward the downstream side, the leading edge of the medium that passes between the first imaging device 118a and the second imaging device 118b is pulled by the second transport roller 119 and the second driven roller 120.

[0051] As the leading edge of the medium is transported along the glass surface G, the distance from the medium to each image sensor of the image capture device 118 at the image capture position becomes constant. Therefore, even when a CIS of a life-size optical system type with a shallow depth of field is used, the occurrence of focus shift is suppressed, and the image capture device 118 can acquire a stable image. In particular, since the distance from the medium to each image sensor of the image capture device 118 in the width direction A2 (main scanning direction) becomes constant, the occurrence of unevenness in the horizontal direction in the input image is suppressed.

[0052] In addition, since the leading edge of the medium is transported along the glass surface G, the leading edge of the medium can clean the glass surface G, i.e., remove foreign matter from the glass surface G. Foreign matter may adhere not only to the glass surface G of the first imaging device 118a but also to the glass surface of the second imaging device 118b, but foreign matter that adheres to the glass surface of the second imaging device 118b will fall due to its own weight and is likely to adhere to the glass surface G of the first imaging device 118a. Since the leading edge of the medium is transported along the glass surface G of the first imaging device 118a disposed below, the medium transport device 100 can also remove foreign matter that has fallen from the glass surface of the second imaging device 118b.

[0053] 8, the first pressing member 133 has a first elastic member 133b. The first elastic member 133b is a spring member such as a torsion recoil spring, and is provided so that one end is supported by the lower housing 101 and the other end is in contact with the first pressing member 133. The first elastic member 133b may be another spring member such as a leaf spring, or a rubber member. The first elastic member 133b applies a pressing force from below to above along the height direction A3 to the first contact surface 133a.

[0054] On the other hand, the second pressing member 136 has a second abutment surface 136a. The second abutment surface 136a abuts against the fourth shaft 135 and presses the fourth shaft 135. The second abutment surface 136a is formed to be parallel to the medium transport surface. The second pressing member 136 also has a second elastic member 136b. The second elastic member 136b is a spring member such as a torsion recoil spring, and is provided so that one end is supported by the lower housing 101 and the other end abuts against the second pressing member 136. The second elastic member 136b may be another spring member such as a leaf spring, or a rubber member. The second elastic member 136b applies a pressing force from below to above along the height direction A3 to the second abutment surface 136a.

[0055] Fig. 9 is a schematic diagram for explaining the operation of the transport mechanism 130. Fig. 9 is a schematic diagram of the transport mechanism 130 as viewed from above.

[0056] As described above, the first abutment surface 133a of the first pressing member 133 is inclined downward toward the downstream side, and the first elastic member 133b presses the center of the width direction A2 of the second shaft 132 upward. As a result, the first pressing member 133 presses the center of the width direction A2 of the second shaft 132 perpendicular to the medium conveying direction toward the first shaft 131 side, and presses it toward the downstream side in the medium conveying direction A1. Therefore, as shown in FIG. 9, the second shaft 132 is curved so that the center of the width direction A2 is located downstream and the end of the width direction A2 is located upstream. As a result, each of the first driven rollers 117, which has the second shaft 132 as a rotation axis, rotates to convey the medium toward the outside of the width direction A2, and the medium is conveyed by being pulled toward the outside.

[0057] Therefore, the medium conveying device 100 can suppress the occurrence of wrinkles on the medium. If wrinkles occur on the conveyed medium, there is a possibility that the gradation may decrease and noise may occur in an image captured of the medium, particularly in a color image or a grayscale image. By suppressing the occurrence of wrinkles on the medium, the medium conveying device 100 can suppress the decrease in gradation and the occurrence of noise in the input image caused by wrinkles on the medium.

[0058] In particular, the first driven roller 117 provided below the first conveying roller 116 is disposed upstream of the first conveying roller 116, and the first abutting surface 133a of the first pressing member 133 presses the center of the second shaft 132 in the width direction A2 upward. Therefore, if the first pressing member 133 does not press the center of the second shaft 132 in the width direction A2 toward the downstream side, the second shaft 132 is curved so that the center of the width direction A2 is disposed upstream so as to release the pressing force by the first elastic member 133b. As a result, each of the first driven rollers 117, which has the second shaft 132 as a rotation axis, rotates so as to convey the medium toward the inside of the width direction A2, and the medium is conveyed so as to be pressed toward the inside. Therefore, wrinkles are likely to occur in the medium. In the medium conveying device 100, the first pressing member 133 presses the center portion of the second shaft 132 in the width direction A2 toward the downstream side, thereby making it possible to effectively suppress the occurrence of wrinkles in the medium.

[0059] On the other hand, the second driven roller 120 provided below the second conveying roller 119 is disposed downstream of the second conveying roller 119, and the second abutting surface 136a of the second pressing member 136 presses the center of the fourth shaft 135 in the width direction A2 upward. Therefore, the fourth shaft 135 is curved so that the center of the width direction A2 is disposed downstream so as to release the pressing force of the second elastic member 136b. As a result, each second driven roller 120 with the fourth shaft 135 as its rotation axis rotates so as to convey the medium toward the outside in the width direction A2, and the medium is conveyed as if pulled toward the outside. Therefore, the occurrence of wrinkles in the medium is suppressed.

[0060] As described above, the second abutment surface 136a of the second pressing member 136 is formed to be parallel to the medium transport surface. Therefore, the second pressing member 136 presses the center part of the fourth shaft 135 in the width direction A2 perpendicular to the medium transport direction upward (towards the third shaft 134) along the height direction A3 perpendicular to the medium transport surface. In this way, the second pressing member 136 prevents the fourth shaft 135 from bending too much, and prevents damage to the medium caused by excessive force being applied to the outside.

[0061] Meanwhile, in the medium conveying device 100, the first shaft 131 which is the rotation axis of the first conveying roller 116 and the third shaft 134 which is the rotation axis of the second conveying roller 119 are provided so as to extend straight in a linear manner. This allows the medium conveying device 100 to ensure the medium conveying force of the first conveying roller 116 and the second conveying roller 119, and to convey the medium appropriately.

[0062] In addition, like the first pressing member 133, the second pressing member 136 may press the central portion of the fourth shaft 135 in the width direction A2 toward the downstream side, and curve the fourth shaft 135 so that the central portion in the width direction A2 is positioned on the downstream side.

[0063] Furthermore, the first contact surface 133a of the first pressing member 133 may be formed to be parallel to the medium transport surface instead of being inclined with respect to the medium transport surface. In this case, the first elastic member 133b of the first pressing member 133 is provided to apply a force to the first pressing member 133 in a direction inclined with respect to the height direction A3 so that the first pressing member 133 presses the second shaft 132 downstream in the medium transport direction A1.

[0064] FIG. 10 is a block diagram showing a schematic configuration of the medium conveying device 100. As shown in FIG.

[0065] In addition to the components described above, the medium conveying device 100 further includes a motor 141, an interface device 142, a storage device 150, a processing circuit 160, and the like.

[0066] The motor 141 has one or more motors, and generates a driving force for rotating the rotation shaft of the feed roller 112, the rotation shaft of the separation roller 113, the first shaft 131, and the third shaft 134 in response to a control signal from the processing circuit 160. In this way, the motor 141 rotates the feed roller 112, the separation roller 113, the first conveyor roller 116, and the second conveyor roller 119 to convey the medium.

[0067] The interface device 142 has an interface circuit conforming to a serial bus such as USB, and is electrically connected to an information processing device (not shown, for example, a personal computer, a mobile information terminal, etc.) to transmit and receive input images and various information. Also, instead of the interface device 142, a communication unit having an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals through a wireless communication line in accordance with a predetermined communication protocol may be used. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network). The communication unit may have a wired communication interface device for transmitting and receiving signals through a wired communication line in accordance with a communication protocol such as a wired LAN.

[0068] The storage device 150 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. The storage device 150 also stores computer programs, databases, tables, and the like used for various processes of the medium conveying device 100. The computer programs may be installed in the storage device 150 from a computer-readable portable recording medium using a known setup program or the like. The portable recording medium is, for example, a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or the like.

[0069] The processing circuit 160 operates based on a program previously stored in the storage device 150. The processing circuit is, for example, a CPU (Central Processing Unit). The processing circuit 160 may be, for example, a DSP (digital signal processor), an LSI (large scale integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array).

[0070] The processing circuit 160 is connected to the operation device 105, the display device 106, the first medium sensor 111, the ultrasonic sensor 114, the second medium sensor 115, the imaging device 118, the motor 141, the interface device 142, the storage device 150, etc., and controls each of these components. The processing circuit 160 performs drive control of the motor 141, imaging control of the imaging device 118, etc., based on the first medium signal and the second medium signal received from the first medium sensor 111 and the second medium sensor 115. The processing circuit 160 acquires an input image from the imaging device 118, and transmits it to the information processing device via the interface device 142.

[0071] FIG. 11 is a diagram showing a schematic configuration of the storage device 150 and the processing circuit 160. As shown in FIG.

[0072] 11, the storage device 150 stores a control program 151, a detection program 152, a pressing control program 153, and the like. Each of these programs is a functional module implemented by software that runs on a processor. The processing circuit 160 reads each program stored in the storage device 150 and operates according to the read program. In this way, the processing circuit 160 functions as a control unit 161, a detection unit 162, and a pressing control unit 163.

[0073] FIG. 12 is a flowchart showing an example of the operation of the medium reading process of the medium conveying device 100.

[0074] An example of the operation of the medium reading process of the medium conveying device 100 will be described below with reference to the flowchart shown in Fig. 12. Note that the flow of the operation described below is executed mainly by the processing circuit 160 in cooperation with each element of the medium conveying device 100 based on a program stored in advance in the storage device 150.

[0075] First, the control unit 161 waits until a user inputs an instruction to read a medium using the operation device 105 or an information processing device, and an operation signal instructing the user to read a medium is received from the operation device 105 or the interface device 142 (step S101).

[0076] Next, control unit 161 acquires a first medium signal from first medium sensor 111, and determines whether or not a medium is placed on placement table 103 based on the acquired first medium signal (step S102). If no medium is placed on placement table 103, control unit 161 ends the series of steps.

[0077] On the other hand, if a medium is placed on the placement table 103, the control unit 161 drives the motor 141 to rotate the feed roller 112, the separation roller 113, the first conveyor roller 116, and the second conveyor roller 119 to convey the medium (step S103).

[0078] Next, control unit 161 waits until the leading edge of the medium passes the position of second medium sensor 115 (step S104). Control unit 161 periodically acquires a second medium signal from second medium sensor 115, and determines that the leading edge of the medium has passed the position of second medium sensor 115 when the signal value of the second medium signal changes from a value indicating that the medium is not present to a value indicating that the medium is present.

[0079] Next, the control unit 161 causes the imaging device 118 to capture an image of the medium, acquires an input image from the imaging device 118, and outputs the acquired input image by transmitting it to the information processing device via the interface device 142 (step S105).

[0080] Next, control unit 161 determines whether or not a medium remains on mounting table 103 based on the first medium signal received from first medium sensor 111 (step S106). If a medium remains on mounting table 103, control unit 161 returns the process to step S104, and repeats the processes of steps S104 to S106.

[0081] On the other hand, if there is no medium remaining on the mounting table 103, the control unit 161 controls the motor 141 to stop the feed roller 112, the separation roller 113, the first conveying roller 116, and the second conveying roller 119 (step S107), and ends the series of steps.

[0082] As described above in detail, the medium conveying device 100 straightens the first shaft 131 that is the rotation axis of the first conveying roller 116 while curving only the second shaft 132 that is the rotation axis of the first driven roller 117, thereby preventing the occurrence of wrinkles in the medium while ensuring the medium conveying force. Therefore, the medium conveying device 100 is able to convey the medium well.

[0083] In particular, the medium conveying device 100 can suppress the occurrence of wrinkles in the medium between the feed roller 112 and separation roller 113 (separation section) and the first conveying roller 116 and first driven roller 117 (conveying section).

[0084] Furthermore, the medium conveying device 100 rotates each of the first driven rollers 117 toward the outside in the width direction A2 by pressing the center of the second shaft 132 in the width direction A2 using only one first pressing member 133 with an inclined first contact surface 133a. This makes it possible for the medium conveying device 100 to suppress the occurrence of wrinkles in the medium while suppressing an increase in device costs.

[0085] In the medium conveying device 100, the first shaft 131, which is the rotation axis (drive axis) of the first conveying roller 116, is provided so as to extend straight in a linear manner without being curved. This makes it possible for the medium conveying device 100 to suppress metal fatigue of the first shaft 131 and wear between the first shaft 131 and the bearing of the first shaft 131, and suppress a reduction in the device lifespan.

[0086] In general, in order to maintain the stability of the medium conveying force, the shaft of the conveying roller needs to be increased in diameter (thickened shaft) to reduce the bending caused by the pressing force from the driven roller. If the shaft of the conveying roller is curved while the shaft diameter of the conveying roller is increased, the reaction force acting on the shaft of the conveying roller increases, and the stability of the medium conveying force is impaired. In particular, when the medium conveying device supports the conveyance of large media such as A3 paper, the shaft that is the rotation shaft of each conveying roller becomes longer, and the reaction force acting on the shaft increases. On the other hand, if the shaft diameter of the rotation shaft of the conveying roller is reduced (thinned shaft), the vibration of the conveying roller during medium conveyance increases, and the stability of the medium conveying force is impaired. On the other hand, in the medium conveying device 100, the first shaft 131 that is the rotation shaft of the first conveying roller 116 extends linearly, so that no reaction force acts on the first shaft 131, and the stability of the medium conveying force is not impaired even if the first shaft 131 is made thicker.

[0087] Figures 13(A) and (B) are schematic diagrams for explaining a first pressing member 233 in a medium conveying device according to another embodiment. Figures 13(A) and (B) are schematic diagrams of the first pressing member 233 as viewed from the side. Figure 13(A) shows the first pressing member 233 disposed at a first position, and Figure 13(B) shows the first pressing member 233 disposed at a second position different from the first position.

[0088] As shown in FIGS. 13A and 13B, the medium transport device according to this embodiment has a first pressing member 233 instead of the first pressing member 133, and further has a second motor 238 and an angle changing member 239.

[0089] The first pressing member 233 has a first contact surface 233a, a first elastic member 233b, a rotating shaft 233c, and an engaging portion 233d. The first contact surface 233a, like the first contact surface 133a, contacts the second shaft 132 and presses the second shaft 132. The first contact surface 233a is an example of an inclined surface, and is formed so as to be inclined with respect to the medium transport surface, particularly so as to be inclined downward toward the downstream side. The first elastic member 233b has a configuration similar to that of the first elastic member 133b, and applies a pressing force from the bottom to the top along the height direction A3 to the first contact surface 233a. The rotating shaft 233c is fixed to the lower housing 101, and supports the first pressing member 233 so as to be rotatable (swingable). That is, the first pressing member 233, particularly the first contact surface 233a, is provided so as to be rotatable (swingable) about the rotating shaft 233c. The engaging portion 233d is provided so as to engage with the angle changing member 239.

[0090] The second motor 238 generates a second driving force for sliding the angle changing member 239 .

[0091] The angle change member 239 is an example of an angle changer. The angle change member 239 is provided to slide in the direction of arrow A8 by the second driving force generated by the second motor 238 and change the inclination angle of the first contact surface 233a of the first pressing member 233 with respect to the medium conveying surface. The angle change member 239 has an engaged portion 239a. The engaged portion 239a supports the engaging portion 233d of the first pressing member 233 so as to clamp it.

[0092] When the device is started, the angle change member 239 is disposed at the initial position shown in FIG. 13(A), and the first pressing member 233 is disposed at the first position. On the other hand, when the second motor 238 rotates to generate the second driving force, the angle change member 239 moves to the moving position shown in FIG. 13(B), and the first pressing member 233 is disposed at the second position. The engaging portion 233d of the first pressing member 233 moves to the upper left while being sandwiched by the engaged portion 239a of the angle change member 239, and the first pressing member 233 rotates (swings) around the rotating shaft 233c. As a result, the inclination angle of the first contact surface 233a with respect to the medium transport surface changes, and the force with which the first pressing member 233 presses the center portion of the second shaft 132 in the width direction A2 toward the downstream side increases.

[0093] The angle change member 239 may be provided to be slid manually by an operator instead of by the second driving force from the second motor 238 to change the inclination angle of the first contact surface 233a of the first pressing member 233 with respect to the medium conveying surface. As described above, the first driven roller 117 is provided in the lower housing 101, and the first conveying roller 116 is provided in the upper housing 102 that is provided to the lower housing 101 so as to be openable and closable (rotatable) by the hinge H. The hinge H, which is a rotation support part of the upper housing 102, has a certain degree of wobble, and further, the arrangement position (rotation position) of the hinge H varies from device to device. Therefore, the contact state between the first conveying roller 116 and the first driven roller 117 varies from device to device. Therefore, the balance between the component of the force with which the first driven roller 117 presses the first conveyor roller 116 in the medium conveying direction A1 and the component of the force with which the first conveyor roller 116 presses the first conveyor roller 116 in the height direction A3 varies from device to device, and the outward force in the width direction A2 applied to the conveyed medium varies from device to device. In the medium conveying device, the angle change member 239 is provided so as to be able to change the inclination angle of the first contact surface 233a, so that the magnitude of the outward force in the width direction A2 applied to the conveyed medium can be adjusted individually for each device.

[0094] In addition, the angle change member 239 changes the direction of the force with which the first driven roller 117 presses the first conveying roller 116 while keeping constant the overall magnitude of the force, so that the medium conveying force can be kept constant during medium conveyance. Therefore, the medium conveying device can suppress the occurrence of elongation or shrinkage of the medium in the sub-scanning direction in the input image.

[0095] FIG. 14 is a flowchart showing an example of the operation of a medium reading process of the medium conveying device according to the present embodiment.

[0096] The flowchart shown in Fig. 14 is executed in place of the flowchart shown in Fig. 12. The processes of steps S201 to S204 and S207 to S209 in Fig. 14 are similar to the processes of steps S101 to S104 and S105 to S107 in Fig. 12, so their explanation will be omitted and only steps S205 to S206 will be explained below. Note that before the flowchart shown in Fig. 14 is executed, the angle change member 239 is placed at the initial position and the first pressing member 233 is placed at the first position.

[0097] After the leading edge of the medium passes the position of the second medium sensor 115 in step S204, the detection unit 162 detects the thickness of the medium being transported (step S205). The detection unit 162 detects the thickness of the medium based on the ultrasonic signal received from the ultrasonic sensor 114. The ultrasonic waves transmitted by the ultrasonic transmitter 114a and passing through the medium are attenuated by the medium, and the thicker the medium is, the greater the attenuation of the ultrasonic waves. The medium transport device 100 stores in advance in the storage device 150 a table that specifies the relationship between the magnitude of the ultrasonic waves received by the ultrasonic receiver 114b, i.e., the signal value of the ultrasonic signal, and the thickness of the medium. The detection unit 162 refers to the table stored in the storage device 150 and identifies the thickness of the medium corresponding to the signal value of the received ultrasonic signal.

[0098] The detection unit 162 may further determine whether or not a double feed of media has occurred based on the ultrasonic signal received from the ultrasonic sensor 114. When multiple media are transported in an overlapping state, ultrasonic waves that pass through the media are attenuated by the air layer between the overlapping media. Therefore, the detection unit 162 can determine whether or not a double feed of media has occurred based on whether or not the signal value of the ultrasonic signal is equal to or less than the double feed threshold. The double feed threshold is set to a value between the signal value of the ultrasonic signal when one sheet of paper is transported and the signal value of the ultrasonic signal when two sheets of paper are transported. When the detection unit 162 determines that a double feed of media has occurred, the control unit 161 stops the motor 141 to stop the transport and discharge of the media. Note that the control unit 161 may stop the medium reading process after discharging the medium currently being transported. The control unit 161 may also drive the motor 141 to control each roller so that the media remaining in the transport path are transported in reverse and returned to the placement table 103 before being re-fed (separated). This eliminates the need for the user to re-place and re-feed the medium on the placement table 103, and the control unit 161 can improve user convenience. Furthermore, the control unit 161 may notify the user by displaying information indicating that a duplicate medium feed has occurred on the display device 106 or by transmitting the information to the information processing device via the interface device 142.

[0099] The detection unit 162 may detect the thickness of the medium using a thickness sensor other than the ultrasonic sensor 114. The thickness sensor is disposed at the position where the ultrasonic sensor 114 is disposed. The thickness sensor may be disposed at any position on the medium transport path. The thickness sensor includes, for example, a pair of a light emitter and a light receiver provided on one side of the medium transport path, and a pair of a light emitter and a light receiver provided on the other side. The reflected light sensor detects the distance between each pair and each surface of the medium from the time from when one pair irradiates light on one surface of the medium to when it receives the reflected light, and the time from when the other pair irradiates light on the other surface of the medium to when it receives the reflected light. The reflected light sensor generates a thickness signal that indicates the subtraction value obtained by subtracting each detected distance from the distance between the two pairs as the thickness. The medium transport device 100 stores in advance in the storage device 150 a table that specifies the relationship between the signal value of the thickness signal and the thickness of the medium. The detection unit 162 refers to a table stored in the storage device 150 and identifies the thickness of the medium corresponding to the signal value of the received thickness signal. The thickness sensor is not limited to one that uses light, and any other sensor capable of detecting the thickness of the medium, such as a pressure sensor or a thickness sensor using a contact piece, may be used as the thickness sensor. Furthermore, the detection unit 162 may identify the thickness based on a setting specified by the user (designation of cardboard or thin paper, or designation of the type of medium, such as a postcard) instead of or in addition to the thickness detected by the sensor.

[0100] Next, the pressing control unit 163 controls the first pressing member 233 based on the thickness of the medium detected by the detection unit 162 (step S206). The pressing control unit 163 controls the second motor 238 based on the detected thickness of the medium, moves the angle change member 239, and changes the inclination angle of the first contact surface 233a of the first pressing member 233. For example, when the thickness of the medium is greater than the thickness threshold, the pressing control unit 163 does not move the angle change member 239 from the initial position, and places the first pressing member 233 at the first position. On the other hand, when the thickness of the medium is equal to or less than the thickness threshold, the pressing control unit 163 moves the angle change member 239 from the initial position to the moving position, and places the first pressing member 233 at the second position. The thickness threshold is set to a value between the thickness of thin paper that is prone to wrinkles and the thickness of PPC paper that is less likely to wrinkle.

[0101] Note that the pressing control unit 163 may change the position of the angle change member 239 in three or more stages so that the inclination angle of the first contact surface 233a increases as the thickness of the medium decreases (as the medium becomes thinner). This enables the pressing control unit 163 to more finely adjust the magnitude of the force directed outward in the width direction A2 for each medium, and more appropriately suppress the occurrence of wrinkles in the medium.

[0102] In this way, angle change member 239 changes the inclination angle of first contact surface 233a of first pressing member 233 based on the thickness of the medium detected by detection unit 162. This allows the medium transport device to properly transport PPC paper, which is less likely to wrinkle, in accordance with the initial settings of the device, while pulling thin paper, which is more likely to wrinkle, more strongly toward the outside in width direction A2, thereby preventing wrinkles from occurring in the thin paper.

[0103] In addition, the pressing control unit 163 may change the inclination angle of the first contact surface 233a when a user uses the operating device 105 or an information processing device to instruct the user to change the inclination angle of the first contact surface 233a, regardless of the thickness of the medium.

[0104] Furthermore, the control unit 161 may determine whether or not the medium included in the input image has wrinkles, and if it is determined that the medium included in the input image has wrinkles, correct the input image to remove the wrinkles.

[0105] In this case, the control unit 161 uses, for example, machine learning technology to determine whether or not the medium included in the input image has wrinkles. The medium conveying device 100 stores in advance in the storage device 150 a classifier that has been pre-trained to output the degree to which the medium included in the image has wrinkles when an image is input. This classifier is pre-trained, for example, by deep learning or the like, using a sample image that includes a wrinkled medium and / or a sample image that does not include a wrinkled medium. The classifier is trained so that the output value becomes higher as the possibility that the medium included in the input image has wrinkles increases. The control unit 161 inputs the input image to the classifier and obtains the output value output from the classifier. If the output value is equal to or greater than a threshold value, the control unit 161 determines that the medium included in the input image has wrinkles, and if the output value is less than the threshold value, the control unit 161 determines that the medium included in the input image does not have wrinkles.

[0106] When the control unit 161 determines that the medium included in the input image has wrinkles, it corrects the input image so as to remove the wrinkles by applying a filter such as a smoothing filter or a Gaussian filter to the input image.

[0107] In addition, if the control unit 161 determines that the medium included in the input image has wrinkles, it may notify the user by displaying information suggesting a change in the inclination angle of the first contact surface 233a on the display device 106 or by transmitting the information to the information processing device via the interface device 142.

[0108] As described above in detail, the medium transport device is able to transport the medium well even when the inclination angle of the first contact surface 233a of the first pressing member 233 is changed based on the thickness of the medium being transported.

[0109] 15(A), (B), 16(A), and (B) are schematic diagrams for explaining a first pressing member 333 in a medium conveying device according to still another embodiment. Fig. 15(A) and Fig. 16(A) are schematic diagrams of the first pressing member 333 as viewed from the side, and Fig. 15(B) and Fig. 16(B) are schematic diagrams of the first pressing member 333 as viewed from the upstream side. Fig. 15(A) and (B) show the first pressing member 333 disposed at a first position, and Fig. 16(A) and (B) show the first pressing member 333 disposed at a second position different from the first position.

[0110] As shown in Figures 15(A), (B), 16(A) and (B), the medium conveying device of this embodiment has a first pressing member 333 instead of the first pressing member 133, and further has a second motor 338 and a pressing force change member 339.

[0111] The first pressing member 333 has a first contact surface 333a, a first elastic member 333b, and a holding member 333c. The first contact surface 333a contacts the second shaft 132 and presses the second shaft 132, similar to the first contact surface 133a. The first contact surface 333a is an example of an inclined surface, and is formed so as to be inclined with respect to the medium transport surface, particularly so as to be inclined downward toward the downstream side. The first elastic member 333b has a configuration similar to that of the first elastic member 133b, and applies a pressing force from the bottom to the top along the height direction A3 to the first contact surface 333a. However, one end of the first elastic member 333b is supported by the holding member 333c, not the lower housing 101. The holding member 333c is provided so as to support one end of the first elastic member 333b.

[0112] The second motor 338 generates a third driving force for rotationally moving a cam member of a pressing force change member 339, which will be described later.

[0113] The pressing force change member 339 is an example of a pressing force change unit. The pressing force change member 339 is provided to change the pressing force of the first pressing member 333 pressing the first driven roller 117 toward the first conveying roller 116 by rotating the cam member in the direction of the arrow A9 by the third driving force generated by the second motor 338. The pressing force change member 339 has a cam member 339a and a rotating shaft 339b. The cam member 339a is, for example, a plate cam provided so as to be rotatable by the third driving force generated by the second motor 338. The cam member 339a is provided so as to abut against a surface of the holding member 333c opposite to the surface supporting the first elastic member 333b. The rotating shaft 339b is the rotating shaft of the cam member 339a and is attached to the second motor 338.

[0114] When the device is started, the cam member 339a of the pressing force change member 339 is disposed at the initial position shown in Figs. 15(A) and (B), and the first pressing member 333 is disposed at the first position. On the other hand, when the second motor 338 rotates to generate the third driving force, the cam member 339a rotates and moves to the moving position shown in Figs. 16(A) and (B), and the first pressing member 333 is disposed at the second position. With the rotation of the cam member 339a, the holding member 333c of the first pressing member 333 moves upward, and the force with which the first elastic member 333b presses the first pressing member 333 increases. As a result, the force with which the first pressing member 333 presses the second shaft 132 increases, and the force with which the first driven roller 117 presses the first conveying roller 116 increases.

[0115] Note that pressing force change member 339 may be provided to change the pressing force of first pressing member 333 by being rotated manually by an operator, instead of by the third driving force from second motor 338. As described above, the outward force in width direction A2 applied to the transported medium varies from device to device. In the medium transport device, pressing force change member 339 is provided to change the pressing force of first pressing member 333, so that the magnitude of the outward force in width direction A2 applied to the transported medium can be adjusted individually for each device.

[0116] In particular, since the pressing force change member 339 has a simpler structure than the angle change member 239, the medium conveying device is able to adjust the outward force in the width direction A2 applied to the medium being conveyed individually for each device while suppressing an increase in device costs.

[0117] The medium conveying device according to this embodiment executes a medium reading process similar to the medium reading process shown in Fig. 14. In this case, before the flowchart shown in Fig. 14 is executed, the cam member 339a of the pressing force change member 339 is placed in the initial position, and the first pressing member 333 is placed in the first position.

[0118] However, in step S205, the pressing control unit 163 controls the second motor 338 based on the detected thickness of the medium to rotate the cam member 339a and change the pressing force applied by the first pressing member 333 to press the first driven roller 117 toward the first conveyance roller 116. For example, when the thickness of the medium is greater than the thickness threshold, the pressing control unit 163 does not rotate the cam member 339a from the initial position and places the first pressing member 333 at the first position. On the other hand, when the thickness of the medium is equal to or less than the thickness threshold, the pressing control unit 163 rotates the cam member 339a from the initial position to the moving position and places the first pressing member 333 at the second position.

[0119] Note that the pressing control unit 163 may change the position of the cam member 339a in three or more stages so that the pressing force by the first pressing member 333 increases as the thickness of the medium decreases (as the medium becomes thinner). This enables the pressing control unit 163 to more finely adjust the magnitude of the force directed outward in the width direction A2 for each medium, and more appropriately suppress the occurrence of wrinkles in the medium.

[0120] In this way, the pressing force change member 339 changes the pressing force with which the first pressing member 333 presses the first driven roller 117 toward the first conveyor roller 116, based on the thickness of the medium detected by the detection unit 162. This allows the medium conveying device to properly convey PPC paper, which is less prone to wrinkles, in accordance with the initial settings of the device, while pulling thin paper, which is more prone to wrinkles, more strongly toward the outside in the width direction A2, thereby preventing wrinkles from occurring in the thin paper.

[0121] In addition, the pressure control unit 163 may change the pressure applied by the pressure force change member 339 when a user uses the operation device 105 or an information processing device to instruct a change in the pressure applied by the pressure force change member 339, regardless of the thickness of the medium.

[0122] In addition, the control unit 161 may determine whether or not the medium included in the input image has wrinkles, and if it determines that the medium included in the input image has wrinkles, it may correct the input image to remove the wrinkles or notify the user of a suggestion to change the pressing force.

[0123] As described above in detail, the medium transport device is able to transport the medium well even when the pressing force of the first pressing member 333 is changed based on the thickness of the medium being transported.

[0124] 17 is a schematic diagram for explaining a support member 437 of a medium conveying device according to still another embodiment. FIG 17 is a perspective view of the first driven roller 117 and the second shaft 132.

[0125] 17, the support member 437 is used instead of the support member 137, and is provided so as to support the second shaft 132 on the outer side of the two second driven rollers 120, i.e., at the end in the width direction A2 perpendicular to the medium conveying direction. The support member 437 has a circular hole, and the end in the width direction A2 of the second shaft 132 is inserted into the hole, so that the support member 437 rotatably supports the second shaft 132. In this way, the second shaft 132 is provided so as to be rotatable. On the other hand, the second driven roller 120 is fixed to the second shaft 132 so as to rotate with the rotation of the second shaft 132.

[0126] In addition, when the support member 437 is used instead of the support member 137, the first pressing member 233 and the angle changing member 239, or the first pressing member 333 and the pressing force changing member 339 may be used instead of the first pressing member 133.

[0127] As described above in detail, the medium conveying device is able to convey the medium well even when the second shaft 132 is provided rotatably.

[0128] 18 and 19 are schematic diagrams for explaining a transport mechanism 530 of a medium transport device according to still another embodiment. Fig. 18 is a schematic diagram of the transport mechanism 530 as viewed from above. Fig. 19 is a schematic diagram of the transport mechanism 530 as viewed from the side.

[0129] The medium conveying device according to this embodiment has each part that the medium conveying device 100 has. However, as shown in Figures 18 and 19, the medium conveying device has a conveying mechanism 530 instead of the conveying mechanism 130. The conveying mechanism 530 has a similar configuration to the conveying mechanism 130. However, the conveying mechanism 530 has a second shaft 532 and a first pressing member 533 instead of the second shaft 132 and the first pressing member 133.

[0130] The second shaft 532 has a similar configuration to the second shaft 132. However, the second shaft 532 is inclined so that the center of the width direction A2 perpendicular to the medium conveying direction is located downstream of the end in the medium conveying direction A1. In particular, the second shaft 532 is inclined so as to be curved. The first driven roller 117 is provided on the second shaft 532 so as to be rotatable along a direction perpendicular to the extension direction of the second shaft 532. The second shaft 532 is provided so as not to rotate, and the first driven roller 117 is provided so as to be rotatable relative to the second shaft 532. The second shaft 532 is disposed upstream of the first shaft 131, and the first driven roller 117 is disposed upstream of the first conveying roller 116.

[0131] The first pressing member 533 is disposed between the two first driven rollers 117, i.e., at the center in the width direction A2 perpendicular to the medium transport direction, so as to abut against the second shaft 532. The first pressing member 533 is provided so as to abut against the lower side of the second shaft 532 so as to press the second shaft 532 towards the first shaft 131, i.e., upward. The first pressing member 533 has a first abutment surface 533a and a first elastic member 533b.

[0132] The first contact surface 533a contacts the second shaft 532 and presses the second shaft 532. The first contact surface 533a is formed to be parallel to the medium transport surface. The first elastic member 533b has a configuration similar to that of the first elastic member 133b, and is provided such that one end is supported by the lower housing 101 and the other end contacts the first pressing member 533. The first elastic member 533b applies a pressing force from below to above along the height direction A3 to the first contact surface 533a.

[0133] In this case as well, each of the first driven rollers 117, which has the second shaft 532 as its rotation axis, rotates to transport the medium outward in the width direction A2, and the medium is transported as if pulled outward, thereby suppressing the occurrence of wrinkles in the medium. Meanwhile, the first shaft 131, which is the rotation axis of the first transport roller 116, is provided so as to extend straight in a linear manner. This allows the medium transport device to ensure the medium transport force of the first transport roller 116 and transport the medium appropriately.

[0134] Furthermore, since the second shaft 532 is curved in advance, the first contact surface 533a of the first pressing member 533 does not need to have an inclination. This makes it possible for the medium conveying device to use common parts for the first pressing member 533 and the second pressing member 136, thereby enabling a reduction in device costs.

[0135] When the second shaft 532 is used instead of the second shaft 132, the first pressing member 333 and the pressing force change member 339 may be used instead of the first pressing member 133. Also, the supporting member 437 may be used instead of the supporting member 137, the second shaft 532 may be rotatably provided, and the first driven roller 117 may be fixed to the second shaft 532 so as to rotate with the rotation of the second shaft 532.

[0136] As described above in detail, the medium conveying device is able to convey the medium well even when the second shaft 532 is inclined so as to be curved.

[0137] Fig. 20 is a schematic diagram for explaining a transport mechanism 630 of a medium transport device according to still another embodiment. Fig. 20 is a schematic diagram of the transport mechanism 630 as viewed from above.

[0138] The medium conveying device according to this embodiment has each part that the medium conveying device 100 has. However, as shown in FIG. 20, the medium conveying device has a conveying mechanism 630 instead of the conveying mechanism 130. The conveying mechanism 630 has a configuration similar to that of the conveying mechanism 530. However, the conveying mechanism 630 has a second shaft 632 instead of the second shaft 532. The second shaft 632 has a configuration similar to that of the second shaft 532. However, the second shaft 632 is inclined so as to be bent.

[0139] In this case as well, each of the first driven rollers 117, which has the second shaft 632 as its rotation axis, rotates to transport the medium outward in the width direction A2, and the medium is transported as if pulled outward, thereby suppressing the occurrence of wrinkles in the medium. Meanwhile, the first shaft 131, which is the rotation axis of the first transport roller 116, is provided so as to extend straight in a linear manner. This allows the medium transport device to ensure the medium transport force of the first transport roller 116 and transport the medium appropriately.

[0140] Furthermore, since the second shaft 632 is bent in advance, the first contact surface 533a of the first pressing member 533 does not need to have an inclination. This makes it possible for the medium conveying device to use common parts for the first pressing member 533 and the second pressing member 136, thereby enabling a reduction in device costs.

[0141] When the second shaft 632 is used instead of the second shaft 132, the first pressing member 333 and the pressing force change member 339 may be used instead of the first pressing member 133. Also, the supporting member 437 may be used instead of the supporting member 137, the second shaft 632 may be rotatably provided, and the first driven roller 117 may be fixed to the second shaft 632 so as to rotate with the rotation of the second shaft 632.

[0142] As described above in detail, the medium conveying device is able to convey the medium well even when the second shaft 532 is inclined so as to bend.

[0143] 21 and 22 are schematic diagrams for explaining a transport mechanism 730 of a medium transport device according to still another embodiment. Fig. 21 is a schematic diagram of the transport mechanism 730 seen from above, and Fig. 22 is a schematic diagram of the transport mechanism 730 seen from the side.

[0144] The medium conveying device according to this embodiment has each part that the medium conveying device 100 has. However, as shown in Figures 21 and 22, the medium conveying device has a conveying mechanism 730 instead of the conveying mechanism 130. The conveying mechanism 730 has a first conveying roller 716, a first driven roller 717, a second conveying roller 719, a second driven roller 720, a first shaft 731, a second shaft 732, a first pressing member 733, a third shaft 734, a fourth shaft 735, a second pressing member 736, and the like.

[0145] The first conveying roller 716, the first driven roller 717, the second conveying roller 719, the second driven roller 720, the first shaft 731, the second shaft 732, the first pressing member 733, the third shaft 734, the fourth shaft 735 and the second pressing member 736 have the same configuration as the first conveying roller 116, the first driven roller 117, the second conveying roller 119, the second driven roller 120, the first shaft 131, the second shaft 132, the first pressing member 133, the third shaft 134, the fourth shaft 135 and the second pressing member 136, respectively.

[0146] However, the first conveyor roller 716, the second conveyor roller 719, the first shaft 731, and the third shaft 734 are provided in the lower housing 101. Meanwhile, the first driven roller 717, the second driven roller 720, the second shaft 732, the first pressing member 733, the fourth shaft 735, and the second pressing member 736 are provided in the upper housing 102. The second shaft 732 and the first driven roller 717 are respectively disposed downstream of the first shaft 731 and the first conveyor roller 716. Meanwhile, the fourth shaft 735 and the second driven roller 720 are respectively disposed upstream of the third shaft 734 and the second conveyor roller 719.

[0147] The second shaft 732 is provided so as to extend linearly in the width direction A2. The first pressing member 733 is an example of a second pressing portion, and is provided so as to abut against the upper side of the second shaft 732 so as to press the second shaft 732 toward the first shaft 731, i.e., downward. The first pressing member 733 has a first abutment surface 733a and a first elastic member 733b. The first abutment surface 733a is formed so as to be parallel to the medium transport surface. The first elastic member 733b has a configuration similar to that of the first elastic member 133b, and is provided so as to have one end supported by the upper housing 102 and the other end abut against the rear surface side of the first pressing member 733. The first elastic member 733b applies a pressing force from above to below along the height direction A3 to the first abutment surface 733a.

[0148] The fourth shaft 735 is provided so as to extend substantially parallel to the width direction A2. The second pressing member 736 is an example of a pressing portion, and is provided so as to abut against the upper side of the fourth shaft 735 so as to press the fourth shaft 735 toward the third shaft 734, i.e., downward. The second pressing member 736 has a second abutment surface 736a and a second elastic member 736b. The second abutment surface 736a is an example of an inclined surface, and is formed so as to be inclined with respect to the medium transport surface, particularly so as to be inclined upward toward the downstream side. As a result, the second pressing member 736 is provided so as to press the center part of the second shaft 732 in the width direction A2 perpendicular to the medium transport direction to the downstream side of the medium transport direction A1 when pressing the second shaft 732 from above along the height direction A3. The second elastic member 736b has a configuration similar to that of the second elastic member 136b, and is provided so that one end is supported by the upper housing 102 and the other end is in contact with the second pressing member 736. The second elastic member 736b applies a pressing force from above to below to the second contact surface 736a along a height direction A3 perpendicular to the medium transport surface.

[0149] As a result, the fourth shaft 735 is curved so that the center portion in the width direction A2 is located downstream and the end portion in the width direction A2 is located upstream. Therefore, each second driven roller 720 having the fourth shaft 735 as its rotation axis rotates to transport the medium toward the outside in the width direction A2, and the medium is transported as if pulled toward the outside, thereby suppressing the occurrence of wrinkles in the medium.

[0150] In particular, the second driven roller 720 provided above the second conveying roller 719 is disposed upstream of the second conveying roller 719, and the second abutting surface 736a of the second pressing member 736 presses the center of the width direction A2 of the fourth shaft 735 downward. Therefore, if the second pressing member 736 does not press the center of the width direction A2 of the fourth shaft 735 toward the downstream side, the fourth shaft 735 curves so that the center of the width direction A2 is disposed upstream so as to release the pressing force of the second elastic member 736b. As a result, each second driven roller 720 with the fourth shaft 735 as the rotation axis rotates so as to convey the medium toward the inside of the width direction A2, and the medium is conveyed so as to be pressed toward the inside. Therefore, wrinkles are likely to occur in the medium. In the medium conveying device, the second pressing member 736 presses the center portion of the fourth shaft 735 in the width direction A2 toward the downstream side, thereby making it possible to effectively suppress the occurrence of wrinkles in the medium.

[0151] On the other hand, the first driven roller 717 provided above the first conveying roller 716 is disposed downstream of the first conveying roller 716, and the first abutting surface 733a of the first pressing member 733 presses the center of the second shaft 732 in the width direction A2 downward. Therefore, the second shaft 732 is curved so that the center of the width direction A2 is disposed downstream so as to release the pressing force of the first elastic member 733b. As a result, the second shaft 732 is curved so that the center of the width direction A2 is disposed downstream and the end of the width direction A2 is disposed upstream. Therefore, each of the first driven rollers 717, which has the second shaft 732 as a rotation axis, rotates to convey the medium toward the outside of the width direction A2, and the medium is conveyed as if pulled toward the outside, so that the occurrence of wrinkles in the medium is suppressed.

[0152] As described above, the first abutment surface 733a of the first pressing member 733 is formed to be parallel to the medium transport surface. Therefore, the first pressing member 733 presses the center portion of the second shaft 732 in the width direction A2 perpendicular to the medium transport direction downward along the height direction A3, that is, toward the first shaft 731. In this way, the first pressing member 133 prevents the second shaft 132 from bending too much so that the center portion in the width direction A2 is positioned downstream, and prevents the medium from being damaged due to excessive outward force being applied to the medium.

[0153] Meanwhile, the first shaft 731 which is the rotation axis of the first transport roller 716 and the third shaft 734 which is the rotation axis of the second transport roller 719 are provided so as to extend straight in a linear manner. This allows the medium transport device to ensure the medium transport force of the first transport roller 716 and the second transport roller 719, and to transport the medium appropriately.

[0154] In addition, even when the transport mechanism 730 is used instead of the transport mechanism 130, the angle change member 239 may be used, and the second pressing member 736 may be provided rotatably like the first pressing member 233. Alternatively, the pressing force change member 339 may be used, and the second pressing member 736 may be provided to be able to change the pressing force like the first pressing member 333. In addition, the support member 437 may be used instead of the support member 137, the fourth shaft 735 may be provided rotatably, and the second driven roller 720 may be fixed to the fourth shaft 735 so as to rotate with the rotation of the fourth shaft 735. In addition, the fourth shaft 735 may be inclined so as to be curved like the second shaft 532, and the second abutting surface 736a of the second pressing member 736 may be provided so as not to be inclined like the second abutting surface 136a of the second pressing member 136. Alternatively, the fourth shaft 735 may be inclined so as to bend in the same manner as the second shaft 632, and the second abutment surface 736a of the second pressing member 736 may be provided so as not to be inclined in the same manner as the second abutment surface 136a of the second pressing member 136.

[0155] As described above in detail, the medium conveying device is able to convey the medium well even when the second driven roller 720 is provided in the upper housing 102.

[0156] In particular, the medium conveying device 100 can suppress the occurrence of wrinkles in the medium around the second conveying roller 719 and the second driven roller 720.

[0157] 23 is a diagram showing a schematic configuration of a processing circuit 860 in a medium conveying device according to yet another embodiment. The processing circuit 860 is used in place of the processing circuit 160 of the medium conveying device 100, and executes medium reading processing and the like in place of the processing circuit 160. The processing circuit 860 has a control circuit 861, a detection circuit 862, a pressing control circuit 863, and the like. Each of these components may be formed of an independent integrated circuit, microprocessor, firmware, and the like.

[0158] The control circuit 861 is an example of a control unit, and has the same functions as the control unit 161. The control circuit 861 receives an operation signal from the operation device 105 or the interface device 142, a first medium signal from the first medium sensor 111, and a second medium signal from the second medium sensor 115, and controls the motor 141 based on each piece of received information. The control circuit 861 also obtains an input image from the imaging device 118, and outputs it to the interface device 142.

[0159] The detection circuit 862 is an example of a detection unit, and has the same function as the detection unit 162. The detection circuit 862 receives an ultrasonic signal from the ultrasonic sensor 114, detects the thickness of the medium based on the received ultrasonic signal, and outputs the detection result to the pressing control circuit 863.

[0160] The pressing control circuit 863 is an example of a pressing control unit, and has the same function as the pressing control unit 163. The pressing control circuit 863 receives the detection result of the thickness of the medium from the detection circuit 862, and controls the second motor 238 or 338 based on the thickness of the medium.

[0161] As described above in detail, the medium conveying device is able to convey the medium well even when the processing circuit 860 is used.

[0162] Although preferred embodiments have been described above, the embodiments are not limited to these. For example, the medium transport device may be a printer that transports a print object or the like as a medium. In this case, the medium transport device has a printing device instead of the imaging device 118. The printing device is disposed at a position where the imaging device 118 is disposed. The medium transport device can suppress the occurrence of wrinkles in the transported medium (print object), making it possible to perform good printing on the print object. [Explanation of symbols]

[0163] 100 medium conveying device, 116, 716 first conveying roller, 117, 717 first driven roller, 119, 719 second conveying roller, 120, 720 second driven roller, 131, 731 first shaft, 132, 532, 632, 732 second shaft, 133, 233, 333, 533, 733 first pressing member, 134, 734 third shaft, 135, 735 fourth shaft, 136, 736 second pressing member, 162 detection unit, 239 angle change member, 339 pressing force change member

Claims

1. A motor that generates a driving force; a first shaft, at least a central portion of which extends linearly in a direction perpendicular to the medium transport direction and which is provided to rotate in accordance with the driving force; a conveying roller fixed to the first shaft and configured to convey a medium; A second shaft; a driven roller that is rotatably provided on the second shaft and rotates in response to the conveying roller; a pressing portion that presses a central portion of the second shaft in a direction perpendicular to the medium transport direction toward a downstream side in the medium transport direction; A medium transport device comprising:

2. The second shaft is non-rotatably provided, The media transport device according to claim 1 , wherein the driven roller is rotatably mounted on the second shaft.

3. The second shaft is rotatably provided, The media transport device of claim 1 , wherein the driven roller is fixed to the second shaft so as to rotate with rotation of the second shaft.

4. the second shaft is disposed upstream of the first shaft in a medium transport direction, The medium transport device according to claim 1 , wherein the pressing portion presses a central portion of the second shaft in a direction perpendicular to the medium transport direction toward the downstream side in the medium transport direction and toward the first shaft.

5. a third shaft that extends linearly in a direction perpendicular to the medium transport direction and that is adapted to rotate in accordance with the driving force; a second conveying roller fixed to the third shaft and configured to convey a medium; a fourth shaft disposed downstream of the third shaft in a medium transport direction; a second driven roller rotatably provided on the fourth shaft and rotated by the second conveying roller; The media transport device of claim 4 , further comprising a second pressing portion that presses a central portion of the fourth shaft in a direction perpendicular to the media transport direction toward the third shaft along a direction perpendicular to the media transport surface.

6. The pressing portion has an inclined surface that comes into contact with the second shaft, The medium transport device according to claim 1 , further comprising an angle changer that changes an inclination angle of the inclined surface.

7. The method further includes the step of: The medium transport device according to claim 6 , wherein the angle changer changes the inclination angle of the inclined surface based on the detected thickness.

8. 6. The medium transport device according to claim 1, further comprising a pressing force changer that changes a pressing force with which the pressing portion presses the driven roller toward the transport roller.

9. The method further includes the step of: The medium transport device according to claim 8 , wherein the pressing force change unit changes the pressing force based on the detected thickness.

10. A motor that generates a driving force; a first shaft, at least a central portion of which extends linearly in a direction perpendicular to the medium transport direction and which is provided to rotate in accordance with the driving force; a conveying roller fixed to the first shaft and configured to convey a medium; a second shaft inclined so that a center portion in a direction perpendicular to the medium transport direction is located downstream of the end portion in the medium transport direction; a driven roller that is rotatably provided on the second shaft and rotates in response to the conveying roller; A medium transport device comprising:

Images