Media transport 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] The present disclosure relates to a media conveyance device, and particularly to a media conveyance device having a conveyance roller and a driven roller.

Background Art

[0002] Generally, a media conveyance device such as a scanner generates an image by imaging a media conveyed by a conveyance roller. In such a media conveyance device, if wrinkles occur in the conveyed media, noise may be included in the image obtained by imaging the media.

[0003] A document conveyance device including two or more document conveyance rollers for conveying a document and two or more driven rollers facing the document conveyance rollers has been disclosed (see Patent Document 1). In this document conveyance device, a bearing that rotatably supports the document conveyance roller shaft at the axial center of the document conveyance roller shaft supporting the document conveyance roller is provided on the downstream side in the document conveyance direction from a bearing that rotatably supports the document conveyance roller shaft at the end of the document conveyance roller shaft. The document conveyance roller shaft is composed of a single document conveyance roller shaft and is rotatably supported by a third bearing in a curved state toward the downstream side in the document conveyance direction.

[0004] A media conveyance device including a rotationally driven drive roller for conveying a media and a driven roller that nips the media between the drive roller and rotates passively has been disclosed (see Patent Document 2). This media conveyance device includes a pressing member that is disposed on one axial end side and the other axial end side of the rotation shaft of the driven roller and presses the rotation shaft in the direction in which the driven roller contacts the drive roller, and a spacer interposed between the rotation shaft and the pressing member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] Media transport devices are required to transport media efficiently.

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

[0008] A media transport device according to one aspect of the embodiment includes a motor that generates driving force and , A first shaft is provided to rotate according to the power source, a conveyor roller is fixed to the first shaft and conveys a medium, a second shaft is provided on the second shaft and rotates in accordance with the conveyor roller. two Driven roller and, The device has a contact portion that abuts against the second shaft, and an elastic member that presses against the contact portion in such a way that a force is applied to the center between the two driven rollers of the second shaft, toward the downstream side in the media transport direction. Only one contact portion and one elastic member are provided for each of the second shafts. .

[0009] medium In a body conveying device, it is preferable that the driven roller is rotatably mounted relative to the second shaft. In a media transport device, it is preferable that the second shaft is rotatably mounted, and the driven roller is fixed to the second shaft so as to rotate in conjunction with the rotation of the second shaft. In a media transport device, it is preferable that two transport rollers are fixed to the first shaft.

[0010] According to this embodiment, the media transport device is capable of transporting the media efficiently.

[0011] The object and effect of the present invention will be recognized and obtained, in particular, by using the components and combinations indicated in the claims. Both the general description above and the detailed description below are illustrative and descriptive, and do not limit the present invention as described in the claims. [Brief explanation of the drawing]

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

Embodiments for Carrying out the Invention

[0013] Hereinafter, a medium conveyance 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, note that the technical scope of the present invention is not limited to those embodiments, and extends to the invention described in the claims and its equivalents.

[0014] FIG. 1 is a perspective view showing a medium conveyance device 100 configured as an image scanner. The medium conveyance device 100 conveys and images a medium that is a document. The medium is paper, thin paper, thick paper, a card, an envelope, or the like. The medium conveyance device 100 may be a facsimile machine, a copying machine, a printer multifunction peripheral (MFP), or the like. Note that the conveyed medium may not be a document but a printing object or the like, and the medium conveyance device 100 may be a printer or the like.

[0015] The medium conveyance device 100 includes a lower housing 101, an upper housing 102, a placement table 103, a discharge table 104, an operation device 105, a display device 106, and the like. In FIG. 1, arrow A1 indicates the medium conveyance direction, arrow A2 indicates the width direction orthogonal to the medium conveyance direction, and arrow A3 indicates the height direction orthogonal to the medium conveyance surface. Hereinafter, upstream refers to the upstream in the medium conveyance direction A1, and downstream refers to the downstream in the medium conveyance direction A1.

[0016] The upper housing 102 is disposed at a position covering the upper surface of the medium conveyance device 100 and is rotatably engaged with the lower housing 101 by a hinge H so as to be openable and closable during conveyance of the medium, that is, during cleaning inside the medium conveyance device 100.

[0017] The mounting platform 103 engages with the lower housing 101 and places the medium to be fed and transported on it. The discharge platform 104 engages with the upper housing 102 and places the discharged medium on it. The discharge platform 104 may also engage with the lower housing 101.

[0018] The operating device 105 has input devices such as buttons and an interface circuit that acquires signals from the input devices, accepts input operations from the user, and outputs an operation signal corresponding to the user's input operation. The display device 106 has a display including liquid crystal, organic EL (Electro-Luminescence), etc. and an interface circuit that outputs image data to the display, and displays the image data on the display.

[0019] Figure 2 is a diagram illustrating the transport path inside the media transport device 100.

[0020] The transport path inside the media transport device 100 includes a first media sensor 111, a feeding 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, among others.

[0021] Note that 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, but may be multiple. In that case, the multiple feed rollers 112, separation roller 113, first conveyor roller 116, first driven roller 117, second conveyor roller 119 and / or second driven roller 120 are arranged side by side with spacing in the width direction A2.

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

[0023] The first medium sensor 111 is positioned upstream of the feeding 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 mounting 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 mounting 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 feeding roller 112 is provided on the lower housing 101 and separates and feeds the medium placed on the mounting table 103 from the bottom up. The separation roller 113 is a so-called brake roller or retard roller and is provided on the upper housing 102, positioned opposite the feeding roller 112, and rotates in the opposite direction to the medium feeding direction. Alternatively, the feeding roller 112 may be provided on the upper housing 102 and the separation roller 113 on the lower housing 101, and the feeding roller 112 may feed the medium placed on the mounting table 103 from the top up.

[0025] The ultrasonic sensor 114 is positioned downstream of the feeding roller 112 and the separation roller 113, and upstream of the first transport 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 positioned in the upper housing 102 and the lower housing 101, respectively, facing each other across the transport path in the vicinity of the transport path for the medium. 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. Alternatively, the ultrasonic transmitter 114a may be positioned in the lower housing 101, and the ultrasonic receiver 114b may be positioned in the upper housing 102.

[0026] The second medium sensor 115 is positioned downstream of the feeding roller 112 and the separation roller 113, and upstream of the first transport roller 116 and the first driven roller 117, and detects the 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 opposite the light emitter and 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. The light receiver, on the other hand, receives the light emitted by the light emitter and guided by the light guide tube. When medium is present at a position opposite 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 medium is present or absent at the position of the second medium sensor 115, based on the intensity of the received light.

[0027] In addition, a reflective material such as a mirror may be used instead of the light guide tube. Furthermore, the light emitter and light receiver may be provided opposite each other across the medium transport path. The second medium sensor 115 may also detect the presence of the medium by using a contact detection sensor or the like that which supplies a predetermined current when the medium is in contact or when the medium is not in contact.

[0028] The first transport roller 116 and the first driven roller 117 are examples of a transport roller and a driven roller, respectively, and are arranged facing each other downstream of the feeding roller 112. The first transport roller 116 is provided on the upper housing 102 and transports the medium fed by the feeding roller 112 and the separation roller 113 to the imaging device 118. The first driven roller 117 is provided on the lower housing 101 below the first transport roller 116 and rotates in conjunction with the first transport roller 116.

[0029] The imaging device 118 is positioned downstream of the first transport roller 116 and images the medium transported by the first transport roller 116. The imaging device 118 includes a first imaging device 118a and a second imaging device 118b, which are positioned opposite each other across the medium transport path. The first imaging device 118a has a line sensor using a 1:1 optical system type CIS (Contact Image Sensor) with image sensors made of CMOS (Complementary Metal Oxide Semiconductor) arranged linearly in the main scanning direction. The first imaging device 118a also has a lens that forms an image on the image sensor and an A / D converter that amplifies the electrical signal output from the image sensor and performs analog-to-digital (A / D) conversion. The first imaging device 118a generates and outputs an input image by imaging the surface of the transported medium according to control from a processing circuit described later.

[0030] Similarly, the second imaging device 118b has a line sensor with a CIS of the 1:1 optical system type, which has CMOS image sensors arranged linearly in the main scanning direction. The second imaging device 118b also has a lens that forms an image on the image sensor and an A / D converter that amplifies the electrical signal output from the image sensor and performs analog-to-digital (A / D) conversion. The second imaging device 118b generates and outputs an input image by imaging the back surface of the transported medium according to the control from the processing circuit described later.

[0031] Furthermore, the media transport device 100 may have only one of the first imaging device 118a and the second imaging device 118b, and may read only one side of the media. Also, instead of a CIS line sensor of the 1:1 optical system type equipped with a CMOS image sensor, a CIS line sensor of the 1:1 optical system type equipped with a CCD (Charge Coupled Device) image sensor may be used. Alternatively, a reduction optical system type line sensor equipped with a CMOS or CCD image sensor may be used.

[0032] The second transport roller 119 and the second driven roller 120 are arranged downstream of the imaging device 118, facing each other. The second transport roller 119 is provided in the upper housing 102 and is transported by the first transport roller 116 and the first driven roller 117, and discharges the medium imaged by the imaging device 118 to the discharge table 104. The second driven roller 120 is provided in the lower housing 101, below the second transport roller 119, and rotates in conjunction with the second transport roller 119.

[0033] The medium placed on the mounting table 103 is transported between the lower guide 101a and the upper guide 102a toward the medium transport direction A1 as the feed roller 112 rotates in the direction of arrow A4 in Figure 2, i.e., the medium transport direction. The separation roller 113 rotates in the direction of arrow A5, i.e., the opposite direction to the medium transport direction, when medium is being transported. Due to the action of the feed roller 112 and the separation roller 113, when multiple media are placed on the mounting table 103, only the media that are in contact with the feed roller 112 are separated. This restricts the transport of media other than the separated media (preventing double feeding).

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

[0035] Figure 3 is a perspective view illustrating the transport mechanism 130 of the media transport device 100.

[0036] As shown in Figure 3, the conveying mechanism 130 includes a first conveying roller 116, a first driven roller 117, a second conveying roller 119, and a second driven roller 120, as well as a first shaft 131, a second shaft 132, a first pressing member 133, a third shaft 134, a fourth shaft 135, and a second pressing member 136, etc. In the example shown in Figure 3, there are two of each of the first conveying roller 116, the first driven roller 117, the second conveying roller 119, and the second driven roller 120.

[0037] The first shaft 131 extends straight in a linear fashion in the width direction A2 perpendicular to the media transport direction and is configured to rotate according to the driving force generated by a motor, which will be described later. The first transport roller 116 is fixed to the first shaft 131 so as to rotate in conjunction with the rotation of the first shaft 131.

[0038] The second shaft 132 is positioned opposite the first shaft 131 and extends substantially parallel to the width direction A2, which is perpendicular to the media transport direction. The first driven roller 117 is rotatably mounted on the second shaft 132 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 part and is positioned between the two first driven rollers 117, that is, in the center of the width direction A2 perpendicular to the media conveying direction, so as to be in contact with the second shaft 132. In particular, it is preferable that the first pressing member 133 is positioned at the center of the position of each first driven roller 117 in the width direction A2. As a result, the two first driven rollers 117 are positioned symmetrically with respect to the first pressing member 133, and the pressing force applied by each first driven roller 117 to each first conveying roller 116 becomes uniform, so that the media conveying device 100 can suppress the occurrence of media skew. The first pressing member 133 is provided so as to be in contact with the lower side of the second shaft 132 so as to press the second shaft 132 toward the first shaft 131, that is, upward.

[0040] The third shaft 134 extends straight in a linear fashion in the width direction A2 perpendicular to the media transport direction and is configured to rotate according to the driving force generated by a motor, which will be described later. The second transport roller 119 is fixed to the third shaft 134 so as to rotate in conjunction with the rotation of the third shaft 134.

[0041] The fourth shaft 135 is positioned opposite the third shaft 134 and extends straight in a linear fashion in the width direction A2, which is perpendicular to the media transport direction. The second driven roller 120 is rotatably mounted on the fourth shaft 135 in 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 section and is positioned between the two second driven rollers 120, that is, in the center of the width direction A2 perpendicular to the media conveying direction, so as to contact the fourth shaft 135. In particular, it is preferable that the second pressing member 136 is positioned at the center of the position of each second driven roller 120 in the width direction A2. As a result, the two second driven rollers 120 are positioned symmetrically with respect to the second pressing member 136, and the pressing force applied by each second driven roller 120 to each second conveying roller 119 becomes uniform, so that the media conveying device 100 can suppress the occurrence of media skew. The second pressing member 136 is provided so as to contact the lower side of the fourth shaft 135 so as to press the fourth shaft 135 toward the third shaft 134, that is, upward.

[0043] Figures 4 and 5 are schematic diagrams illustrating 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 side view of the first driven roller 117 and the second shaft 132.

[0044] As shown in Figures 4 and 5, the media transport device 100 further includes a support member 137. The support member 137 is made of a resin or metal material and is provided to support the second shaft 132 outside the two first driven rollers 117, that is, at the end in the width direction A2 perpendicular to the media transport direction. The support member 137 has a notch (or opening) into which the end of the second shaft 132 in the width direction A2 is inserted. The notch (or opening) is provided with a flat support surface 137a. On the other hand, the end of the second shaft 132 in the width direction A2 is provided with a supported surface 132a that has been D-cut. By the contact between the support surface 137a and the supported surface 132a, the second shaft 132 is fixed by the support member 137 and is provided so as not to rotate. On the other hand, the first driven rollers 117 are provided so as to be rotatable relative to the second shaft 132.

[0045] Since the first driven roller 117 is rotatably mounted 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 part of the second shaft 132 in the width direction A2 is pressed downstream, as will be described later.

[0046] Figures 6 and 7(A) and 7(B) are schematic diagrams illustrating the first pressing member 133. Figure 6 is a perspective view of the first pressing member 133 with the second shaft 132 placed on it, Figure 7(A) is a perspective view of the first pressing member 133 without the second shaft 132 placed on it, and Figure 7(B) is a schematic diagram of the first pressing member 133 viewed from the side.

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

[0048] Figure 8 is a schematic diagram illustrating the operation of the conveying mechanism 130. Figure 8 is a schematic diagram of the conveying mechanism 130 viewed from the side.

[0049] As described above, the second shaft 132 is positioned opposite the first shaft 131, and the fourth shaft 135 is positioned opposite the third shaft 134. However, as shown in Figure 8, the second shaft 132 is positioned upstream of the first shaft 131. As a result, the first driven roller 117, which is located below the first conveyor roller 116, is positioned upstream of the first conveyor roller 116. Therefore, the nip surfaces of the first conveyor roller 116 and the first driven roller 117 are inclined downwards towards the downstream side. On the other hand, the fourth shaft 135 is positioned downstream of the third shaft 134. As a result, the second driven roller 120, which is located below the second conveyor roller 119, is positioned downstream of the second conveyor roller 119. Therefore, the nip surfaces of the second conveyor roller 119 and the second driven roller 120 are inclined upwards towards the downstream side.

[0050] In Figure 8, path R represents the path through which the leading edge of the transported medium ideally passes. Because the nip surfaces of the first transport roller 116 and the first driven roller 117 are inclined downward towards the downstream side, the leading edge of the medium transported by the first transport roller 116 and the first driven roller 117 is transported downward. The leading edge of the medium contacts the glass surface G of the first imaging device 118a and is transported along the glass surface G. Because the nip surfaces of the second transport roller 119 and the second driven roller 120 are inclined upward towards the downstream side, the leading edge of the medium that has passed 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 imaging device 118 remains constant at the imaging position. Therefore, even when a CIS of the 1:1 optical system type with a shallow depth of field is used, the occurrence of focus shifts is suppressed, and the imaging device 118 can acquire stable images. In particular, since the distance from the medium to each image sensor of the imaging device 118 remains constant in the width direction A2 (main scanning direction), the occurrence of horizontal unevenness in the input image is suppressed.

[0052] Furthermore, 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. However, foreign matter adhering to the glass surface of the second imaging device 118b is likely to fall due to its own weight and adhere to the glass surface G of the first imaging device 118a. As the leading edge of the medium is transported along the glass surface G of the first imaging device 118a, which is positioned 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] Furthermore, as shown in Figure 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, with one end supported by the lower housing 101 and the other end 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, etc. The first elastic member 133b applies a pressing force to the first contact surface 133a from below to above along the height direction A3.

[0054] On the other hand, the second pressing member 136 has a second contact surface 136a. The second contact surface 136a contacts and presses the fourth shaft 135. The second contact 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, with one end supported by the lower housing 101 and the other end in contact with the second pressing member 136. The second elastic member 136b may be another spring member such as a leaf spring, or a rubber member, etc. The second elastic member 136b applies a pressing force to the second contact surface 136a from below to above along the height direction A3.

[0055] Figure 9 is a schematic diagram illustrating the operation of the conveying mechanism 130. Figure 9 is a schematic diagram of the conveying mechanism 130 viewed from above.

[0056] As described above, the first contact surface 133a of the first pressing member 133 is inclined downward towards the downstream side, and the first elastic member 133b presses upward on the central part of the second shaft 132 in the width direction A2. As a result, the first pressing member 133 presses the central part of the second shaft 132 in the width direction A2, which is perpendicular to the media transport direction, toward the first shaft 131, and also presses toward the downstream side in the media transport direction A1. Therefore, as shown in Figure 9, the second shaft 132 is curved such that the central part in the width direction A2 is positioned downstream and the ends in the width direction A2 are positioned upstream. As a result, each first driven roller 117 with the second shaft 132 as its axis of rotation rotates to transport the media toward the outside in the width direction A2, and the media is transported as if being pulled toward the outside.

[0057] Therefore, the media transport device 100 can suppress the occurrence of wrinkles in the media. When wrinkles occur in the transported media, there is a possibility that the gradation quality will decrease and noise will occur in the image captured from that media, especially in color or grayscale images. By suppressing the occurrence of wrinkles in the media, the media transport device 100 can suppress the decrease in gradation quality and the occurrence of noise in the input image caused by wrinkles in the media.

[0058] In particular, the first driven roller 117, located below the first conveyor roller 116, is positioned upstream of the first conveyor roller 116, and the first contact surface 133a of the first pressing member 133 presses upward against the center of the second shaft 132 in the width direction A2. Therefore, if the first pressing member 133 does not press downstream against the center of the second shaft 132 in the width direction A2, the second shaft 132 will curve so that the center of the width direction A2 is positioned upstream, thereby releasing the pressing force from the first elastic member 133b. As a result, each first driven roller 117, with the second shaft 132 as its axis of rotation, rotates to convey the medium toward the inside of the width direction A2, and the medium is conveyed while being pressed toward the inside. Therefore, wrinkles are likely to occur in the medium. In the media transport device 100, the first pressing member 133 presses the central part of the second shaft 132 in the width direction A2 toward the downstream side, thereby effectively suppressing the occurrence of wrinkles in the media.

[0059] On the other hand, the second driven roller 120, which is located below the second conveyor roller 119, is positioned downstream of the second conveyor roller 119, and the second contact surface 136a of the second pressing member 136 presses upward against the center of the fourth shaft 135 in the width direction A2. Therefore, the fourth shaft 135 is curved so that the center of the width direction A2 is positioned downstream, in order to release the pressing force from the second elastic member 136b. As a result, each second driven roller 120, with the fourth shaft 135 as its axis of rotation, rotates to convey the medium outward in the width direction A2, and the medium is conveyed as if being pulled outward. Therefore, the occurrence of wrinkles in the medium is suppressed.

[0060] As described above, the second contact surface 136a of the second pressing member 136 is formed to be parallel to the media transport surface. Therefore, the second pressing member 136 presses the central part of the fourth shaft 135 in the width direction A2 perpendicular to the media transport direction upward (towards the third shaft 134) along the height direction A3 perpendicular to the media transport surface. As a result, the second pressing member 136 can prevent the fourth shaft 135 from bending too much and prevent excessive outward force from being applied to the media, which could cause damage to the media.

[0061] On the other hand, in the media 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 to extend straight in a linear manner. As a result, the media conveying device 100 can ensure the conveying force of the media by the first conveying roller 116 and the second conveying roller 119, and can convey the media appropriately.

[0062] Furthermore, the second pressing member 136 may, similar to the first pressing member 133, press the central part of the fourth shaft 135 in the width direction A2 toward the downstream side, causing the fourth shaft 135 to curve so that the central part of the width direction A2 is positioned toward the downstream side.

[0063] Furthermore, the first contact surface 133a of the first pressing member 133 may be formed parallel to the medium transport surface, rather than being inclined with respect to the medium transport surface. In that case, the first elastic member 133b of the first pressing member 133 is provided to apply 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] Figure 10 is a block diagram showing the schematic configuration of the media transport device 100.

[0065] In addition to the configuration described above, the media transport device 100 further includes a motor 141, an interface device 142, a storage device 150, and a processing circuit 160.

[0066] The motor 141 has one or more motors and generates driving force to rotate the rotation axis of the feeding roller 112, the rotation axis of the separation roller 113, the first shaft 131, and the third shaft 134 according to control signals from the processing circuit 160. As a result, the motor 141 rotates the feeding roller 112, the separation roller 113, the first transport roller 116, and the second transport roller 119 to transport the medium.

[0067] The interface device 142 has an interface circuit similar to a serial bus such as USB, and electrically connects to an information processing device (not shown) (e.g., a personal computer, a portable information terminal, etc.) to transmit and receive input images and various types of information. Alternatively, instead of the interface device 142, a communication unit may be used that has an antenna for transmitting and receiving wireless signals and a wireless communication interface device for transmitting and receiving signals via a wireless communication line according to a predetermined communication protocol. The predetermined communication protocol is, for example, a wireless LAN (Local Area Network). The communication unit may also have a wired communication interface device for transmitting and receiving signals via a wired communication line according to a communication protocol such as a wired LAN.

[0068] The storage device 150 includes memory devices such as RAM (Random Access Memory) and ROM (Read Only Memory), fixed disk devices such as hard disks, or portable storage devices such as flexible disks and optical disks. The storage device 150 also stores computer programs, databases, tables, etc., used for various processes of the media transport device 100. The computer programs may be installed into the storage device 150 from a computer-readable portable recording medium using a known setup program. Examples of portable recording media include CD-ROMs (compact disc read-only memory) and DVD-ROMs (digital versatile disc read-only memory).

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

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

[0071] Figure 11 shows a schematic configuration of the storage device 150 and the processing circuit 160.

[0072] As shown in Figure 11, the storage device 150 stores the control program 151, the detection program 152, and the press control program 153, among others. Each of these programs is a functional module implemented by software running on the processor. The processing circuit 160 reads each program stored in the storage device 150 and operates according to each program it has read. As a result, the processing circuit 160 functions as the control unit 161, the detection unit 162, and the press control unit 163.

[0073] Figure 12 is a flowchart showing an example of the operation of the media reading process of the media transport device 100.

[0074] The following describes an example of the operation of the media reading process of the media transport device 100, referring to the flowchart shown in Figure 12. The operation flow described below is mainly executed by the processing circuit 160 in cooperation with each element of the media transport device 100, based on a program pre-stored in the storage device 150.

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

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

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

[0078] Next, the control unit 161 waits until the leading edge of the medium passes the position of the second medium sensor 115 (step S104). The control unit 161 periodically acquires a second medium signal from the second medium sensor 115, and determines that the leading edge of the medium has passed the position of the second medium sensor 115 when the signal value of the second medium signal changes from a value indicating the absence of medium to a value indicating the presence of medium.

[0079] Next, the control unit 161 causes the imaging device 118 to image the medium, acquires the 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, the control unit 161 determines whether or not there is any medium remaining on the mounting table 103 based on the first medium signal received from the first medium sensor 111 (step S106). If there is any medium remaining on the mounting table 103, the control unit 161 returns to step S104 and repeats the process from 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 feeding roller 112, the separation roller 113, the first transport roller 116, and the second transport roller 119 (step S107), and ends the series of steps.

[0082] As described in detail above, the media conveying device 100 ensures media conveying force while suppressing the occurrence of wrinkles in the media by straightening the first shaft 131, which is the rotation axis of the first conveying roller 116, while curving only the second shaft 132, which is the rotation axis of the first driven roller 117. Therefore, the media conveying device 100 is able to convey the media smoothly.

[0083] In particular, the media transport device 100 is capable of suppressing the occurrence of wrinkles in the media between the feeding roller 112 and the separating roller 113 (separation section) and the first transport roller 116 and the first driven roller 117 (transport section).

[0084] Furthermore, the media transport device 100 rotates each first driven roller 117 toward the outside in the width direction A2 by pressing the central part of the second shaft 132 in the width direction A2 using only one first pressing member 133 with an inclined first contact surface 133a. As a result, the media transport device 100 is able to suppress the occurrence of wrinkles in the media while suppressing an increase in the device cost.

[0085] Furthermore, in the media conveying device 100, the first shaft 131, which is the rotation axis (drive shaft) of the first conveying roller 116, is provided to extend straight in a linear manner without curving. As a result, the media conveying device 100 can suppress metal fatigue of the first shaft 131 and wear between the first shaft 131 and its bearing, thereby suppressing a reduction in the device's lifespan.

[0086] Generally, to maintain the stability of the media transport force, the shaft diameter of the conveyor roller needs to be increased (the shaft diameter increased) to reduce deflection caused by the pressing force from the driven roller. If the shaft diameter of the conveyor roller's shaft is increased while the shaft is curved, the reaction force acting on the shaft increases, impairing the stability of the media transport force. In particular, when a media transport device supports the transport of large media such as A3 paper, the shafts that are the rotating axes of each conveyor roller become longer, and the reaction force acting on the shafts increases. On the other hand, if the shaft diameter of the conveyor roller's shaft is decreased (the shaft diameter increased), the vibration of the conveyor roller during media transport increases, impairing the stability of the media transport force. However, in the media transport device 100, since the first shaft 131, which is the rotating axis of the first conveyor roller 116, extends in a straight line, no reaction force is acted on the first shaft 131, and the stability of the media transport force is not impaired even if the first shaft 131 is made thicker.

[0087] Figures 13(A) and (B) are schematic diagrams illustrating the first pressing member 233 in a media transport device according to another embodiment. Figures 13(A) and (B) are schematic diagrams of the first pressing member 233 viewed from the side. Figure 13(A) shows the first pressing member 233 positioned at a first position, and Figure 13(B) shows the first pressing member 233 positioned at a second position different from the first position.

[0088] As shown in Figures 13(A) and (B), the media transport device according to this embodiment has a first pressing member 233 instead of the first pressing member 133, and further includes 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 and presses the second shaft 132. The first contact surface 233a is an example of an inclined surface and is formed to be inclined with respect to the medium transport surface, in particular to be inclined downwards towards the downstream side. The first elastic member 233b has the same configuration as the first elastic member 133b and applies a pressing force to the first contact surface 233a from below to above along the height direction A3. The rotating shaft 233c is fixed to the lower housing 101 and supports the first pressing member 233 so that it can rotate (oscillate). That is, the first pressing member 233, in particular the first contact surface 233a, is provided so that it can rotate (oscillate) around the rotating shaft 233c. The engaging portion 233d is provided to engage with the angle changing member 239.

[0090] The second motor 238 generates a second driving force to slide the angle-changing member 239.

[0091] The angle-changing member 239 is an example of an angle-changing section. The angle-changing member 239 slides in the direction of arrow A8 by the second driving force generated by the second motor 238, and is provided to change the inclination angle of the first contact surface 233a of the first pressing member 233 with respect to the medium transport surface. The angle-changing member 239 has an engaged portion 239a. The engaged portion 239a supports the engaging portion 233d of the first pressing member 233 by clamping it.

[0092] When the device is started, the angle changing member 239 is positioned in the initial position shown in Figure 13(A), and the first pressing member 233 is positioned in the first position. On the other hand, when the second motor 238 rotates and generates a second driving force, the angle changing member 239 moves to the movement position shown in Figure 13(B), and the first pressing member 233 is positioned in the second position. The engaging portion 233d of the first pressing member 233 is held by the engaged portion 239a of the angle changing member 239 and moves upward and to the left, causing the first pressing member 233 to rotate (oscillate) around the rotation axis 233c. As a result, the inclination angle of the first contact surface 233a with respect to the media transport surface changes, and the force with which the first pressing member 233 presses the central part of the width direction A2 of the second shaft 132 downstream increases.

[0093] Furthermore, the angle-changing member 239 may be provided to slide manually by an operator, rather than by a 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 media transport surface. As described above, the first driven roller 117 is provided on the lower housing 101, and the first transport roller 116 is provided on the upper housing 102, which is provided to the lower housing 101 so as to be openable and closable (rotatable) by a hinge H. The hinge H, which is the rotation support part of the upper housing 102, has a certain degree of play, and furthermore, the position of the hinge H (rotation position) varies from device to device. Therefore, the contact state between the first transport roller 116 and the first driven roller 117 varies from device to device. Therefore, the balance between the force component of the first driven roller 117 pushing the first conveyor roller 116 in the media conveying direction A1 and the force component of the force pushing 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 media also varies from device to device. In the media conveying device, an angle changing member 239 is provided so that the inclination angle of the first contact surface 233a can be changed, thereby allowing the magnitude of the outward force in the width direction A2 applied to the conveyed media to be adjusted individually for each device.

[0094] Furthermore, the angle-changing member 239 changes the direction of the force while keeping the overall magnitude of the force that the first driven roller 117 exerts on the first transport roller 116 constant, thus maintaining a constant medium transport force during medium transport. Therefore, the medium transport device can suppress the occurrence of stretching or shrinking of the medium in the sub-scanning direction within the input image.

[0095] Figure 14 is a flowchart showing an example of the operation of the media reading process of the media transport device according to this embodiment.

[0096] The flowchart shown in Figure 14 is executed instead of the flowchart shown in Figure 12. The processes in steps S201-S204 and S207-S209 in Figure 14 are the same as the processes in steps S101-S104 and S105-S107 in Figure 12, so their explanation is omitted, and only steps S205-S206 will be explained below. Note that before the flowchart shown in Figure 14 is executed, the angle changing member 239 is placed in its initial position and the first pressing member 233 is placed in its first position.

[0097] In step S204, after the leading edge of the medium passes the position of the second medium sensor 115, 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 emitted by the ultrasonic transmitter 114a and transmitted through the medium are attenuated by the medium, and the thicker the medium, the greater the attenuation of the ultrasonic waves. The medium transport device 100 stores in the storage device 150 a table that defines 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] Furthermore, 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 overlapping, the ultrasonic waves that penetrate 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 by checking whether or not the signal value of the ultrasonic signal is below 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. If the detection unit 162 determines that a double feed of media has occurred, the control unit 161 stops the motor 141 and stops the transport and discharge of the media. The control unit 161 may also discharge the media currently being transported before stopping the media reading process. Alternatively, the control unit 161 may drive the motor 141 and control each roller to reverse-fly the media remaining on the transport path back to the mounting table 103 before re-feeding (separating). This eliminates the need for users to re-place the medium on the loading tray 103 and re-feed it, allowing the control unit 161 to improve user convenience. The control unit 161 may also notify the user by displaying information indicating that a double feed of the medium has occurred on the display device 106 or by transmitting it to the information processing device via the interface device 142.

[0099] Furthermore, the detection unit 162 may also detect the thickness of the medium using a thickness sensor other than the ultrasonic sensor 114. The thickness sensor is positioned at the same location as the ultrasonic sensor 114. The thickness sensor may be positioned at any location on the medium transport path. The thickness sensor includes, for example, a pair of light emitters and light receivers provided on one side of the medium transport path, and a pair of light emitters and light receivers provided on the other side. The reflected light sensor detects the distance between each pair and each surface of the medium from the time it takes for one pair to irradiate one surface of the medium with light and receive the reflected light, and the time it takes for the other pair to irradiate the other surface of the medium with light and receive the reflected light. The reflected light sensor generates a thickness signal that shows the thickness as a subtracted value obtained by subtracting the detected distances from the distance between the two pairs. The medium transport device 100 stores in the storage device 150 a table that defines 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. Note that the thickness sensor is not limited to one that uses light; 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. In addition, the detection unit 162 may identify the thickness based on settings specified by the user (specification of cardboard or thin paper, or specification of the type of medium such as a postcard) in addition to or instead of the thickness detected by the sensor.

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

[0101] Furthermore, the pressure control unit 163 may change the position of the angle changing 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 (the thinner the medium is). This makes it possible for the pressure control unit 163 to more precisely adjust the magnitude of the force directed outward in the width direction A2 for each medium, thereby more effectively suppressing the occurrence of wrinkles in the medium.

[0102] In this way, the angle-changing member 239 changes the inclination angle of the first contact surface 233a of the first pressing member 233 based on the thickness of the medium detected by the detection unit 162. As a result, the medium transport device can appropriately transport PPC paper and the like, which are less prone to wrinkling, according to the device's initial settings, while pulling thinner paper, which is prone to wrinkling, more strongly toward the outside of the A2 width direction, thereby suppressing the occurrence of wrinkles in the thinner paper.

[0103] Furthermore, the pressure control unit 163 may change the inclination angle of the first contact surface 233a if the user instructs to change the inclination angle of the first contact surface 233a using the operating device 105 or the information processing device, 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 determines that the medium included in the input image has wrinkles, it may 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 contained in the input image has wrinkles. The medium transport device 100 stores a pre-trained classifier in the storage device 150 that outputs the degree to which the medium contained in the image has wrinkles when an image is input. This classifier is pre-trained using, for example, deep learning, with sample images that contain wrinkled medium and / or sample images that do not contain wrinkled medium. The classifier is trained so that the output value is higher the higher the probability that the medium contained in the input image has wrinkles. 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 above a threshold, the control unit 161 determines that the medium contained in the input image has wrinkles, and if the output value is below the threshold, it determines that the medium contained in the input image does not have wrinkles.

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

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

[0108] As detailed above, the media transport device can effectively transport the media 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 media being transported.

[0109] Figures 15(A), (B), 16(A), and (B) are schematic diagrams illustrating the first pressing member 333 in a media transport device according to yet another embodiment. Figures 15(A) and 16(A) are schematic diagrams of the first pressing member 333 viewed from the side, and Figures 15(B) and 16(B) are schematic diagrams of the first pressing member 333 viewed from the upstream side. Figures 15(A) and (B) show the first pressing member 333 positioned at a first position, and Figures 16(A) and (B) show the first pressing member 333 positioned at a second position different from the first position.

[0110] As shown in Figures 15(A), (B) and 16(A), (B), the media transport device according to this embodiment has a first pressing member 333 instead of the first pressing member 133, and further includes a second motor 338 and a pressing force changing 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, like the first contact surface 133a, contacts and presses the second shaft 132. The first contact surface 333a is an example of an inclined surface and is formed to be inclined with respect to the medium conveying surface, in particular to be inclined downwards towards the downstream side. The first elastic member 333b has the same configuration as the first elastic member 133b and applies a pressing force to the first contact surface 333a from below to above along the height direction A3. However, one end of the first elastic member 333b is supported by the holding member 333c, not by the lower housing 101. The holding member 333c is provided to support one end of the first elastic member 333b.

[0112] The second motor 338 generates a third driving force to rotate the cam member of the pressing force changing member 339, which will be described later.

[0113] The pressing force changing member 339 is an example of a pressing force changing section. The pressing force changing member 339 is provided to change the pressing force applied by the first pressing member 333 to the first driven roller 117 toward the first conveyor roller 116 by rotating a cam member in the direction of arrow A9 using a third driving force generated by the second motor 338. The pressing force changing member 339 has a cam member 339a and a rotating shaft 339b. The cam member 339a is, for example, a plate cam that is rotatably mounted by a third driving force generated by the second motor 338. The cam member 339a is provided to abut against the surface of the holding member 333c opposite to the surface that supports 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 changing member 339 is positioned in the initial position shown in Figures 15(A) and (B), and the first pressing member 333 is positioned in the first position. On the other hand, when the second motor 338 rotates and generates a third driving force, the cam member 339a rotates to the moving position shown in Figures 16(A) and (B), and the first pressing member 333 is positioned in the second position. As the cam member 339a rotates, 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 conveyor roller 116 increases.

[0115] Furthermore, the pressing force changing member 339 may be rotated and moved manually by an operator, rather than by the third driving force from the second motor 338, to change the pressing force applied by the first pressing member 333. As described above, the force applied to the conveyed medium in the width direction A2 outward varies from device to device. In a medium conveying device, by providing a pressing force changing member 339 that can change the pressing force applied by the first pressing member 333, the magnitude of the force applied to the conveyed medium in the width direction A2 outward can be adjusted individually for each device.

[0116] In particular, since the pressing force changing member 339 has a simpler structure compared to the angle changing member 239, the media conveying device can adjust the force applied to the conveyed media in the width direction A2 outward, individually for each device, while suppressing an increase in device costs.

[0117] The media transport device according to this embodiment performs a media reading process similar to the media reading process shown in Figure 14. In this case, before the flowchart shown in Figure 14 is executed, the cam member 339a of the pressing force changing member 339 is positioned at the initial position, and the first pressing member 333 is positioned at the first position.

[0118] However, in step S205, the pressure 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 transport roller 116. For example, if the thickness of the medium is greater than the thickness threshold, the pressure control unit 163 does not rotate the cam member 339a from its initial position and places the first pressing member 333 in the first position. On the other hand, if the thickness of the medium is less than or equal to the thickness threshold, the pressure control unit 163 rotates the cam member 339a from its initial position to the moving position and places the first pressing member 333 in the second position.

[0119] Furthermore, the pressing control unit 163 may change the position of the cam member 339a in three or more stages so that the pressing force applied by the first pressing member 333 increases as the thickness of the medium decreases (the thinner the medium is). This allows the pressing control unit 163 to more precisely adjust the magnitude of the force directed outward in the width direction A2 for each medium, thereby more effectively suppressing the occurrence of wrinkles in the medium.

[0120] In this way, the pressing force changing member 339 changes the pressing force applied by the first pressing member 333 to the first driven roller 117 towards the first transport roller 116, based on the thickness of the medium detected by the detection unit 162. As a result, the medium transport device can appropriately transport PPC paper and the like, which are less prone to wrinkling, according to the device's initial settings, while pulling thin paper, which is prone to wrinkling, more strongly toward the outside of the A2 width direction, thereby suppressing the occurrence of wrinkles in thin paper.

[0121] Furthermore, the pressure control unit 163 may change the pressure applied by the pressure changing member 339 if the user instructs the user to change the pressure applied by the pressure changing member 339 using the operating device 105 or the information processing device, regardless of the thickness of the medium.

[0122] Furthermore, the control unit 161 may determine whether 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 detailed above, the media transport device can effectively transport the media even when the pressing force applied by the first pressing member 333 is changed based on the thickness of the media being transported.

[0124] Figure 17 is a schematic diagram illustrating a support member 437 of a media transport device according to yet another embodiment. Figure 17 is a perspective view of the first driven roller 117 and the second shaft 132.

[0125] As shown in Figure 17, the support member 437 is used in place of the support member 137 and is provided to support the second shaft 132 on the outside of the two second driven rollers 120, that is, at the end in the width direction A2 perpendicular to the media conveying direction. The support member 437 has a circular hole formed in it, and the end of the second shaft 132 in the width direction A2 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 to be rotatable. On the other hand, the second driven roller 120 is fixed to the second shaft 132 so as to rotate in conjunction with the rotation of the second shaft 132.

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

[0127] As detailed above, the media transport device is capable of effectively transporting the media even when the second shaft 132 is rotatably mounted.

[0128] Figures 18 and 19 are schematic diagrams illustrating a transport mechanism 530 of a media transport device according to yet another embodiment. Figure 18 is a schematic diagram of the transport mechanism 530 viewed from above. Figure 19 is a schematic diagram of the transport mechanism 530 viewed from the side.

[0129] The media transport device according to this embodiment has the parts of the media transport device 100. However, as shown in Figures 18 and 19, the media transport device has a transport mechanism 530 instead of the transport mechanism 130. The transport mechanism 530 has the same configuration as the transport mechanism 130. However, the transport 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 the same configuration as the second shaft 132. However, the second shaft 532 is inclined such that the central part in the width direction A2 perpendicular to the media conveying direction is located downstream of the end in the media conveying direction A1. In particular, the second shaft 532 is inclined to curve. The first driven roller 117 is rotatably mounted on the second shaft 532 along a direction perpendicular to the extension direction of the second shaft 532. The second shaft 532 is mounted non-rotatably, while the first driven roller 117 is mounted rotatably relative to the second shaft 532. The second shaft 532 is located upstream of the first shaft 131, and the first driven roller 117 is located upstream of the first conveying roller 116.

[0131] The first pressing member 533 is positioned between the two first driven rollers 117, that is, in the center of the width direction A2 perpendicular to the media transport direction, so as to contact the second shaft 532. The first pressing member 533 is provided so as to contact the lower side of the second shaft 532 so as to press the second shaft 532 toward the first shaft 131, that is, upward. The first pressing member 533 has a first contact surface 533a and a first elastic member 533b.

[0132] The first contact surface 533a contacts and presses against 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 the same configuration as the first elastic member 133b, with one end supported by the lower housing 101 and the other end in contact with the first pressing member 533. The first elastic member 533b applies a pressing force to the first contact surface 533a from below to above along the height direction A3.

[0133] In this case as well, each first driven roller 117, with the second shaft 532 as its axis of rotation, rotates to transport the medium outward in the width direction A2, and the medium is transported as if being pulled outward, thus suppressing the occurrence of wrinkles in the medium. On the other hand, the first shaft 131, which is the axis of rotation of the first transport roller 116, is provided to extend straight in a linear manner. As a result, the medium transport device can ensure the transport force of the medium by the first transport roller 116 and transport the medium appropriately.

[0134] Furthermore, because the second shaft 532 is pre-curved, the first contact surface 533a of the first pressing member 533 does not need to be inclined. As a result, the media transport device can use common parts for the first pressing member 533 and the second pressing member 136, thereby reducing the cost of the device.

[0135] Furthermore, if a second shaft 532 is used instead of the second shaft 132, the first pressing member 333 and the pressing force changing member 339 may be used instead of the first pressing member 133. Also, a support member 437 may be used instead of the support member 137, the second shaft 532 may be rotatably mounted, and the first driven roller 117 may be fixed to the second shaft 532 so as to rotate in conjunction with the rotation of the second shaft 532.

[0136] As detailed above, the media transport device is now capable of transporting media effectively even when the second shaft 532 is inclined in a curved manner.

[0137] Figure 20 is a schematic diagram illustrating a transport mechanism 630 of a media transport device according to yet another embodiment. Figure 20 is a schematic diagram of the transport mechanism 630 viewed from above.

[0138] The media transport device according to this embodiment has the parts of the media transport device 100. However, as shown in Figure 20, the media transport device has a transport mechanism 630 instead of the transport mechanism 130. The transport mechanism 630 has the same configuration as the transport mechanism 530. However, the transport mechanism 630 has a second shaft 632 instead of the second shaft 532. The second shaft 632 has the same configuration as the second shaft 532. However, the second shaft 632 is inclined to bend.

[0139] In this case as well, each first driven roller 117, with the second shaft 632 as its axis of rotation, rotates to transport the medium outward in the width direction A2, and the medium is transported as if being pulled outward, thus suppressing the occurrence of wrinkles in the medium. On the other hand, the first shaft 131, which is the axis of rotation of the first transport roller 116, is provided to extend straight in a linear manner. As a result, the medium transport device can ensure the transport force of the medium by the first transport roller 116 and transport the medium appropriately.

[0140] Furthermore, because the second shaft 632 is pre-bent, the first contact surface 533a of the first pressing member 533 does not need to be inclined. As a result, the media transport device can use common parts for the first pressing member 533 and the second pressing member 136, thereby reducing the device cost.

[0141] Furthermore, if a second shaft 632 is used instead of the second shaft 132, the first pressing member 333 and the pressing force changing member 339 may be used instead of the first pressing member 133. Also, a support member 437 may be used instead of the support member 137, the second shaft 632 may be rotatably mounted, and the first driven roller 117 may be fixed to the second shaft 632 so as to rotate in conjunction with the rotation of the second shaft 632.

[0142] As detailed above, the media transport device is now capable of transporting the media effectively even when the second shaft 532 is inclined to bend.

[0143] Figures 21 and 22 are schematic diagrams illustrating a conveying mechanism 730 of a media conveying device according to yet another embodiment. Figure 21 is a schematic diagram of the conveying mechanism 730 viewed from above, and Figure 22 is a schematic diagram of the conveying mechanism 730 viewed from the side.

[0144] The media transport device according to this embodiment has the parts of the media transport device 100. However, as shown in Figures 21 and 22, the media transport device has a transport mechanism 730 instead of the transport mechanism 130. The transport mechanism 730 includes a first transport roller 716, a first driven roller 717, a second transport 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, and a second pressing member 736, etc.

[0145] The first conveyor roller 716, the first driven roller 717, the second conveyor 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 each have the same configuration as the first conveyor roller 116, the first driven roller 117, the second conveyor 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 transport roller 716, the second transport roller 719, the first shaft 731, and the third shaft 734 are provided in the lower housing 101. On the other hand, 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 positioned downstream of the first shaft 731 and the first transport roller 716, respectively. On the other hand, the fourth shaft 735 and the second driven roller 720 are positioned upstream of the third shaft 734 and the second transport roller 719, respectively.

[0147] The second shaft 732 is provided to extend straight in a linear manner in the width direction A2. The first pressing member 733 is an example of the second pressing part and is provided 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 contact surface 733a and a first elastic member 733b. The first contact surface 733a is formed to be parallel to the medium transport surface. The first elastic member 733b has the same configuration as the first elastic member 133b, with one end supported by the upper housing 102 and the other end abutting against the back side of the first pressing member 733. The first elastic member 733b applies a pressing force to the first contact surface 733a from above to below along the height direction A3.

[0148] The fourth shaft 735 is provided to extend substantially parallel to the width direction A2. The second pressing member 736 is an example of a pressing part and is provided 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 contact surface 736a and a second elastic member 736b. The second contact surface 736a is an example of an inclined surface and is formed to be inclined with respect to the media transport surface, in particular so as to be inclined upward towards the downstream side. As a result, when the second shaft 732 is pressed from above along the height direction A3, the second pressing member 736 is provided to press the central part of the second shaft 732 in the width direction A2 perpendicular to the media transport direction toward the downstream side of the media transport direction A1. The second elastic member 736b has the same configuration as the second elastic member 136b, with one end supported by the upper housing 102 and the other end in contact with the second pressing member 736. The second elastic member 736b applies a pressing force to the second contact surface 736a from top to bottom along the height direction A3 perpendicular to the media transport surface.

[0149] As a result, the fourth shaft 735 is curved such that the central part in the width direction A2 is positioned downstream and the ends in the width direction A2 are positioned upstream. Therefore, each second driven roller 720, with the fourth shaft 735 as its axis of rotation, rotates to transport the medium outward in the width direction A2, and the medium is transported as if being pulled outward, thus suppressing the occurrence of wrinkles in the medium.

[0150] In particular, the second driven roller 720, which is located above the second conveyor roller 719, is positioned upstream of the second conveyor roller 719, and the second contact surface 736a of the second pressing member 736 presses downwards on the central part of the fourth shaft 735 in the width direction A2. Therefore, if the second pressing member 736 does not press downstream on the central part of the fourth shaft 735 in the width direction A2, the fourth shaft 735 will curve so that the central part of the width direction A2 is positioned upstream, in order to release the pressing force from the second elastic member 736b. As a result, each second driven roller 720, with the fourth shaft 735 as its axis of rotation, rotates to convey the medium toward the inside of the width direction A2, and the medium is conveyed while being pressed toward the inside. Therefore, wrinkles are likely to occur in the medium. In the media transport device, the second pressing member 736 presses the central part of the fourth shaft 735 in the width direction A2 toward the downstream side, thereby effectively suppressing the occurrence of wrinkles in the media.

[0151] On the other hand, the first driven roller 717, which is provided above the first conveyor roller 716, is positioned downstream of the first conveyor roller 716, and the first contact surface 733a of the first pressing member 733 presses downwards on the central part of the second shaft 732 in the width direction A2. Therefore, the second shaft 732 is curved so that the central part of the width direction A2 is positioned downstream, in order to release the pressing force from the first elastic member 733b. As a result, the second shaft 732 is curved so that the central part of the width direction A2 is positioned downstream and the ends of the width direction A2 are positioned upstream. Therefore, each first driven roller 717 with the second shaft 732 as its axis of rotation rotates to convey the medium outwards in the width direction A2, and the medium is conveyed as if being pulled outwards, thus suppressing the occurrence of wrinkles in the medium.

[0152] As described above, the first contact 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 central part of the second shaft 732 in the width direction A2, which is perpendicular to the medium transport direction, downward along the height direction A3, that is, towards the first shaft 731. As a result, the first pressing member 133 can prevent the second shaft 132 from curving too much so that the central part in the width direction A2 is positioned downstream, and can prevent excessive outward force from being applied to the medium, which could cause damage to the medium.

[0153] On the other hand, the first shaft 731, which is the rotation axis of the first conveyor roller 716, and the third shaft 734, which is the rotation axis of the second conveyor roller 719, are provided to extend straight in a linear manner. This makes it possible for the media conveying device to ensure the conveying force of the media by the first conveyor roller 716 and the second conveyor roller 719 and to convey the media appropriately.

[0154] Furthermore, even when the conveying mechanism 730 is used instead of the conveying mechanism 130, the angle changing member 239 may be used, and the second pressing member 736 may be rotatably provided in the same manner as the first pressing member 233. Alternatively, the pressing force changing member 339 may be used, and the second pressing member 736 may be provided so that the pressing force can be changed in the same manner as the first pressing member 333. In addition, a support member 437 may be used instead of the support member 137, and the fourth shaft 735 may be rotatably provided, and the second driven roller 720 may be fixed to the fourth shaft 735 so as to rotate in conjunction with the rotation of the fourth shaft 735. Furthermore, the fourth shaft 735 may be inclined to curve in the same manner as the second shaft 532, and the second contact surface 736a of the second pressing member 736 may be provided so as not to be inclined, similar to the second contact surface 136a of the second pressing member 136. Alternatively, the fourth shaft 735 may be inclined to bend in the same way as the second shaft 632, and the second contact surface 736a of the second pressing member 736 may be provided so as not to be inclined, similar to the second contact surface 136a of the second pressing member 136.

[0155] As detailed above, the media transport device is capable of transporting the media effectively even when the second driven roller 720 is provided on the upper housing 102.

[0156] In particular, the media transport device 100 is able to suppress the occurrence of wrinkles in the media around the second transport roller 719 and the second driven roller 720.

[0157] Figure 23 shows a schematic configuration of a processing circuit 860 in a media transport device according to yet another embodiment. The processing circuit 860 is used in place of the processing circuit 160 of the media transport device 100 and performs media reading processing, etc., instead of the processing circuit 160. The processing circuit 860 includes a control circuit 861, a detection circuit 862, and a pressing control circuit 863, etc. Each of these parts may be composed of an independent integrated circuit, microprocessor, firmware, etc.

[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 operation signals from the operating device 105 or 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 the received information. The control circuit 861 also acquires 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 pressure control circuit 863.

[0160] The pressure control circuit 863 is an example of a pressure control unit and has the same functions as the pressure control unit 163. The pressure 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 detailed above, the media transport device is now capable of transporting the media effectively even when using the processing circuit 860.

[0162] While preferred embodiments have been described above, the embodiments are not limited to these. For example, the media transport device may be a printer that transports the object to be printed as a medium. In that case, the media transport device has a printing device instead of an imaging device 118. The printing device is positioned where the imaging device 118 is located. The media transport device can suppress the occurrence of wrinkles in the transported medium (object to be printed), making it possible to print on the object to be printed well. [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 changing member, 339 Pressing force changing member

Claims

1. A motor that generates driving force, A first shaft is provided to rotate in accordance with the aforementioned driving force, A conveying roller fixed to the first shaft for transporting the medium, The second shaft and Two driven rollers are provided on the second shaft and rotate in conjunction with the conveying roller, A contact portion that contacts the second shaft, The second shaft has an elastic member that presses against the contact portion such that a force is applied to the central part between the two driven rollers in the medium transport direction, The contact portion and the elastic member are each provided one at a time for the second shaft. A media transport device characterized by the following features.

2. The medium conveying device according to claim 1, wherein the driven roller is rotatably mounted relative to the second shaft.

3. The second shaft is rotatably mounted, The medium conveying device according to claim 1, wherein the driven roller is fixed to the second shaft so as to rotate in conjunction with the rotation of the second shaft.

4. The media conveying device according to any one of claims 1 to 3, wherein two of the conveying rollers are fixed to the first shaft.

Images