Patent Publication Number: US-9415954-B2

Title: Image reader and sheet feeding device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of Japanese Patent Application No. 2014-069730 filed on Mar. 28, 2014, the contents of which are incorporated herein by reference in its entirety. 
     BACKGROUND 
     There exist a sheet feeding apparatuses that are structured as an image scanner and that include a lower housing, an upper housing, and a sheet tray. A feed roller and an image scanning unit are disposed in the lower housing and the upper housing. A sheet placed on the sheet tray is fed by the feed roller, and a surface of the sheet is scanned by the image scanning unit. Moreover, with the sheet feeding apparatus, a card is fed and a surface of the card is scanned. 
     SUMMARY 
     Aspects of the present disclosure improve a sheet guiding function in an image processing apparatus. According to some aspects, the image processing includes a sheet feeder with a chute, a first tray and a second tray. The first tray may include multiple open positions while the second tray may be opened and closed. According to further aspects, the configuration between the first tray, the second tray and the chute allow for various types of media to be fed and processed through the apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an image scanner according to an example embodiment in a state in which a first tray and a second tray are closed; 
         FIG. 2  is a perspective view of the image scanner according to the example embodiment in a state in which the first tray and the second tray are open; 
         FIG. 3  is a perspective view of the image scanner according to the example embodiment in a state in which the first tray is open and the second tray is closed; 
         FIG. 4  is a side sectional view of the image scanner according to the example embodiment in a state in which the first tray and the second tray are closed; 
         FIG. 5  is a side sectional view of the image scanner according to the example embodiment in a state in which the first tray and the second tray are open; 
         FIG. 6  is a side sectional view of the image scanner according to the example embodiment in a state in which the first tray is open and the second tray is closed; 
         FIG. 7  is a side sectional view of the image scanner according to the example embodiment; 
         FIG. 8  is an enlarged view of region A of  FIG. 7 ; 
         FIG. 9  is a side sectional view of the image scanner according to the example embodiment; 
         FIG. 10  is an enlarged view of region B of  FIG. 9 ; 
         FIG. 11  is a side sectional view of the image scanner according to the example embodiment; 
         FIG. 12  is an enlarged view of region C of  FIG. 11 ; and 
         FIG. 13  is a perspective view of an image scanner according to another example embodiment in a state in which a first tray is open. 
     
    
    
     DETAILED DESCRIPTION 
     In order to reduce the size of a sheet feeding apparatus, a sheet tray may be configured to rotate between an open position and a closed position. A sheet or a card can be placed on the sheet tray in the open position. The sheet tray contacts the upper housing from above in the closed position. In one example, the sheet tray is in the open position regardless of whether the sheet tray supports a sheet or a card, the card being smaller than a sheet. Thus, a large space is needed even when scanning a card, because it is necessary to locate the sheet tray, which is sized so as to be capable of supporting a sheet larger than a card, in the open position. 
     According to further aspects of the present disclosure may provide a sheet feeder for reducing a space needed for scanning a card, which may be smaller than a sheet. 
     Hereinafter, example embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the embodiments described below and can be implemented in various ways and/or with various modifications. 
     1. Structure of Image Scanner  1   
     In the following description, the directions shown by arrows in the drawings (up, down, left, right, front, and back) will be used in order to describe positional relationships between components of an image scanner  1 . 
     As illustrated in  FIGS. 1 to 3 , a sheet feeder such as the image scanner  1  includes a housing  10 , a feed tray  20 , and an output section  30 . As illustrated in  FIGS. 4 to 6 , a conveyance path P, along which a sheet S is fed from the feed tray  20  to the output section  30 , is formed in the housing  10 . The image scanner  1  includes a conveyance mechanism  40 , an image scanning unit  50 , and a power unit (not shown), which are disposed in the housing  10 . 
     1.1. Structure of Housing  10   
     As illustrated in  FIGS. 1 to 3 , the housing  10  has a box-like shape and includes an upper cover  11 , a back cover  12 , left and right side covers  13 L and  13 R, and an inner frame, where the inner frame is covered by these covers  13 L and  13 R. The inner frame is made by assembling together a chute  14 , a frame member (not shown), and the like. The chute  14  is mounted in the housing  10 . The chute  14  is disposed between the side cover  13 L and the side cover  13 R. The chute  14  is disposed on a front side of the back cover  12 . The conveyance path P is defined between upper cover  11  and the chute  14 . The chute  14  guides a fed sheet or card along the conveyance path P. 
     The upper cover  11  is rotatable between an open position, in which the upper cover  11  is located away from the chute  14 , and a closed position in which the upper cover  11  is located near (or closer to) the chute  14 . When a sheet jam occurs or when maintenance is performed, the upper cover  11  is swung so that a back end thereof is lifted, and the upper cover  11  is separated in an upward direction from the chute  14 . 
     A second tray stopper  13 LA is formed in a back part of the side cover  13 L. A second tray stopper  13 RA is formed in a back part of the side cover  13 R. 
     The chute  14  includes a conveyance guide  14 A and side wall portions  14 B and  14 C. The conveyance guide  14 A has a flat plate-like shape and is disposed between the side wall portions  14 B and  14 C. The conveyance guide  14 A extends in the left-right direction and diagonally downward from the back side of the housing  10  to the output section  30 . As illustrated in  FIG. 3 , an upper surface of the conveyance guide  14 A faces an upper guide surface  11 A of the upper cover  11  from below. The side wall portion  14 B is connected to the side cover  13 L. The side wall portion  14 C is connected to the side cover  13 R. The upper surface of the conveyance guide  14 A includes a lower guide surface  14 D. The lower guide surface  14 D and the upper guide surface  11 A define the conveyance path P therebetween, when the upper cover  11  is in the closed position. The lower guide surface  14 D is an example of a chute surface. When the image scanner  1  is placed horizontally, the lower guide surface  14 D forms an inclination angle in the range of, for example, 20 to 30 degrees with a horizontal plane. In one arrangement, the inclination angle is 25 degrees. 
     1.2. Structure of Feed Tray  20   
     The feed tray  20  includes a first tray  21  and a second tray  22 . 
     As illustrated in  FIGS. 1 to 6 , the first tray  21  is attached to the back end of the housing  10  so as to be rotatable around a first rotation axis  21 A, which extends in the left-right direction. The first tray  21  and the housing  10  have a first rotation shaft and bearing (not shown). The extending direction of the first rotation shaft defines the first rotation axis  21 A. Thus, the first tray  21  can rotate around the first rotation axis  21 A in a range from a first closed position, through a second open position, and to a first open position. When the first tray  21  is in the first closed position, which is illustrated in  FIGS. 1 and 4 , a first tray surface  21 D (described below) is located near the back end of the housing  10 . When the first tray  21  is in the first open position, which is illustrated in  FIGS. 3 and 6 , the first tray surface  21 D is located away from the back end of the upper cover and continuous with the back end of the chute  14 . When the first tray  21  is in the second open position, which is illustrated in  FIGS. 2 and 5 , the first tray surface  21 D is located away from the back end of the housing  10  and is disposed between and continuous with the chute  14  and the second tray  22  in an open position. The open position of the second tray  22  will be described below. 
     As illustrated in  FIGS. 11 and 12 , a torsion spring  21 B is fitted onto the first rotation shaft. One end of the torsion spring  21 B is in contact with a contact surface  10 A of the housing  10 , and the other end of the torsion spring  21 B is in contact with a contact surface  21 C of the first tray  21 . Due to a biasing force of the torsion spring  21 B, the first tray  21  is biased from the first open position toward the first closed position. Due to the biasing force of the torsion spring  21 B, when the first tray  21  is in the second open position, the first tray  21  is in contact with the second tray  22  in the open position. 
     As illustrated in  FIGS. 2 to 6 , a surface of the first tray  21  that faces upward when the first tray  21  is in the first open position or the second open position is the first tray surface  21 D for supporting a sheet S. When the first tray  21  is in the first open position, the first tray surface  21 D forms an inclined surface that is continuous with the lower guide surface  14 D of the chute  14 . Side guides  21 E and  21 F are attached to the first tray surface  21 D. The side guide  21 E and  21 F are example of a first side guide and second side guide. 
     The side guides  21 E and  21 F are disposed with a space therebetween in the left-right direction. Each of side guides  21 E and  21 F has a rack (not shown) extending in the left-right direction. A pinion gear is provided in the first tray  21 . The side guides  21 E and  21 F can be slid along the first tray surface  21 D in the left-right direction with each rack engaging the pinion gear. The side guides  21 E and  21 F are configured to be simultaneously slid in opposite directions. 
     As illustrated in  FIGS. 7 to 10 , the first tray  21  includes an engagement protrusion  21 G. The engagement protrusion  21 G includes an extension portion  21 H and an end portion  21 I. In one example, the extension portion  21 H and the end portion  21 I form a first engaging member. The extension portion extends from the first tray  21 . The end portion  21 I extends forward from a lower end of the extension portion  21 H. 
     As illustrated in  FIG. 8 , when the first tray  21  is rotated from the first closed position and is in the second open position, the end portion  21 I is in contact with a second engaging member such as an engagement protrusion  10 B of the housing  10 . 
     When the first tray  21  is rotated from the second open position to the first open position, the end portion  21 I is pressed by the engagement protrusion  10 B in the radial direction of the first rotation shaft. As illustrated in  FIG. 10 , when the end portion  21 I is pressed, the end portion  21 I enters an engagement recess  10 C. The engagement recess  10 C is formed in the vicinity of the engagement protrusion  10 B and is recessed toward the lower guide surface  14 D of the chute  14 . The end portion  21 I, upon entering the engagement recess  10 C, becomes engaged with the engagement recess  10 C. For example, the end portion  21 I protrudes toward the lower guide surface  14 D of the chute  14 . 
     When the first tray  21  is moved to the first open position, a lower end surface  21 J of the first tray  21  contacts a contact surface  10 D of the housing  10 . When the end portion  21 I is engaged with the engagement recess  10 C and the lower end surface  21 J is in contact with the contact surface  10 D, rotation of the first tray  21  beyond the first open position is restricted. As a result, when the end portion  21 I is located in the engagement recess  10 C, the position of the first tray  21  is fixed. 
     As illustrated in  FIGS. 1 to 6 , the second tray  22  is attached to an upper part of the back end of the housing  10  so as to be rotatable around a second rotation axis  22 A, which extends in the left-right direction. The second tray  22  and the housing  10  have a second rotation shaft and bearing (not shown). The extending direction of the second rotation shaft defines the first rotation axis  22 A. The second tray  22  is rotatable until the second tray  22  contacts the second tray stoppers  13 LA and  13 RA. When the second tray  22  is in contact with the second tray stoppers  13 LA and  13 RA, the second tray  22  is in an open position. Thus, the second tray  22  can rotate around the second rotation axis  22 A in a range from a closed position to the open position. As illustrated in  FIGS. 1 and 4 , when the second tray  22  is in the closed position, the second tray  22  is located near an upper surface of the housing  10 . As illustrated in  FIGS. 2 and 5 , when the second tray  22  is in the open position, the second tray  22  is located away from the upper surface of the housing  10  and continuous with the chute  14  and the back end of the first tray  21 . As illustrated in  FIG. 5 , when the second tray  22  is in the open position and the first tray  21 , which is biased from the first open position toward the first closed position, is in contact with the second tray  22 , the first tray  21  is in the second open position. In some examples, the biasing force, with which the first tray  21  is biased from the first open position toward the first closed position, is not large enough to move the second tray  22  from the open position toward the closed position. 
     The second tray  22  is attached to the housing  10  at a position above a position at which the first tray  21  is attached to the housing  10 . For example, the position of the second rotation axis  22 A, around which the second tray  22  rotates, may be above the position of the first rotation axis  21 A, around which the first tray  21  rotates. 
     A surface of the second tray  22  that faces upward when the second tray  22  is in the open position is a second tray surface  22 B for supporting a sheet S. When the second tray  22  is in the open position, the second tray surface  22 B is continuous with the first tray surface  21 D of the first tray  21  in the second open position. 
     When the image scanner  1  is placed on a horizontal surface and the second tray  22  is in the open position, a direction perpendicular to the second tray surface  22 B has a vertically upward component. 
     As illustrated in  FIG. 5 , the length L 1  of the first tray surface  21 D in a sheet conveyance direction is smaller than the length L 2  of the second tray surface  22 B in the conveyance direction. For example, the sheet conveyance direction may correspond to a direction in which a sheet S is fed by a feed roller  41 . As further illustrated in  FIG. 5 , the first tray surface, second tray surface and chute surface may be disposed along the sheet conveyance direction. 
     When the second tray  22  is in the closed position and the first tray  21  is in the first open position as illustrated in  FIG. 9 , the end portion  21 I of the first tray  21  is engaged with the engagement recess  10 C of the housing  10  and the lower end surface  21 J of the first tray  21  is in contact with the contact surface  10 D of the housing  10  as illustrated in  FIG. 10 . As a result, and as illustrated in  FIG. 9 , the first tray  21  in the first open position is engaged with the housing  10 , and the position of the first tray  21  is fixed. The first tray surface  21 D of the first tray  21  in the first open position forms a first angle θ 1  with the lower guide surface  14 D of the chute  14 . The first angle θ 1  is, for example, obtuse angle. When the first angle θ 1  is obtuse angle, the conveyance path P is defined by the first tray surface  21 D and the lower guide surface  14 D. On the other hand, when the first angle θ 1  is not obtuse angle, the conveyance path P is not defined by the first tray surface  21 D and the lower guide surface  14 D. The first angle θ 1  is, for example, in the range of 175 to 180 degrees. When the first angle θ 1  is in the range of 175 to 180 degrees, the first tray surface  21 D and the lower guide surface  14 D may define a straight conveyance path P. In one arrangement, the first angle θ 1  is 180 degrees. 
     When the second tray  22  is in the open position and the first tray  21  is in the second open position as illustrated in  FIG. 7 , the end portion  21 I of the first tray  21  is in contact with the engagement protrusion  10 B of the housing  10  as illustrated in  FIG. 8 . The first tray  21  contacts the second tray  22  in the open position due to a biasing force of the torsion spring  21 B. As illustrated in  FIG. 7 , the first tray surface  21 D of the first tray  21  in the second open position is located between and continuous with the lower guide surface  14 D of the chute  14  and the second tray surface  22 B of the second tray  22 . The first tray surface  21 D of the first tray  21  in the second open position forms a second angle θ 2 , which is smaller than the first angle θ 1 , with the lower guide surface  14 D of the chute  14 . The second angle θ 2  is, for example, obtuse angle. When the second angle θ 2  is obtuse angle and the second tray  22  is in the open position, the conveyance path P is defined by the second tray surface  22 B, the first tray surface  21 D, and the lower guide surface  14 D. On the other hand, when the second angle θ 2  is not obtuse angle, the conveyance path P is not defined by the second tray surface  22 B, the first tray surface  21 D, and the lower guide surface  14 D. The second angle θ 2  is, for example, in the range of 165 to 175 degrees. In one arrangement, the second angle θ 2  is 170 degrees. 
     1.3. Structure of Output Section  30   
     As illustrated in  FIGS. 1 and 2 , the output section  30  is an opening in a lower front part of the housing  10 , which is formed because the upper cover  11  and the back cover  12  are spaced apart (e.g., disposed with a space therebetween). The output section  30  outputs a sheet S that has been conveyed along the conveyance path P. 
     1.4. Structure of Conveyance Mechanism  40   
     As illustrated in  FIGS. 4 to 6 , the conveyance mechanism  40  includes the feed roller  41 , a separation unit  49 , a LF (line feed) roller  42 , and an ejecting roller  43 , which are arranged in this order from upstream to downstream along the conveyance path P. 
     A sheet feeding unit such as the feed roller  41  is mounted in the chute  14 . A roller surface  41 A of the feed roller  41  is exposed to the conveyance path P and protrudes from the lower guide surface  14 D of the conveyance guide  14 A. The roller surface  41 A of the feed roller  41  contacts a sheet S that is conveyed along the conveyance path P. 
     The feed roller  41 , which is driven by a driving unit (not shown), rotates about rotation axis  41 B (as shown  FIG. 7 ). The feed roller  41  rotates in contact with a sheet S that is placed on the first tray surface  21 D and the second tray surface  22 B, thereby feeding the sheet S downstream in the conveyance direction. 
     The separation unit  49  includes a separation pad  47 . The separation pad  47  is a plate-shaped member made of rubber, an elastomer, or the like. The separation unit  49  is attached to the upper cover  11 . In the state in which the separation unit  49  is attached to the upper cover  11 , the separation pad  47  faces the feed roller  41 . When the upper cover  11  is closed, the separation pad  47  is biased by a pressing portion  47 A and pressed against the feed roller  41 . Thus, the separation pad  47  nips sheets S, which are conveyed along the conveyance path P, with the feed roller  41  and further separates the sheets S one by one. 
     Transport units such as the LF roller  42  and the ejecting roller  43  may each be mounted in the chute  14  and located at the conveyance guide  14 A. As illustrated in  FIG. 5 , the sum of the length L 1  and the length L 3  is greater than or equal to the length L 4 . The length L 1  is a length of the first tray surface  21 D in the conveyance direction. The length L 3  is a length from an end of the first tray surface  21 D near the feed roller  41  to the feed roller  41  in the conveyance direction. The length L 4  is a length from the feed roller  41  to the LF roller  42  in the conveyance direction. The LF roller  42  and the ejecting roller  43  are driven by a driving unit (not shown) and rotate in a same conveyance direction as that of the feed roller  41 . 
     A driven roller  42 A is disposed above the LF roller  42  so as to face the LF roller  42 . The driven roller  42 A is mounted in the upper cover  11 . The driven roller  42 A is biased by a biasing member (not shown) and pressed against the LF roller  42 . Thus, the LF roller  42  rotates while nipping a sheet S, which is conveyed along the conveyance path P, with the driven roller  42 A and conveys the sheet S downstream in the conveyance direction. 
     A driven roller  43 A is disposed above the ejecting roller  43  so as to face the ejecting roller  43 . The driven roller  43 A is mounted in the upper cover  11 . The driven roller  43 A is biased by a biasing member (not shown) and pressed against the ejecting roller  43 . Thus, the ejecting roller  43  rotates while nipping a sheet S, which is conveyed along the conveyance path P, with the driven roller  43 A and ejects the sheet S to the output section  30 , which is disposed downstream in the conveyance direction. 
     1.5. Structure of Image Scanning Unit  50   
     As illustrated in  FIGS. 4 to 6 , a sheet processing unit such as the image scanning unit  50  may process sheets such as sheet S fed by the feed roller  41 . Image scanning unit  50  includes a first scanning unit  51  and a second scanning unit  52 . The first scanning unit  51  and the second scanning unit  52  are located downstream from the LF roller  42  in the conveyance direction and upstream from the ejecting roller  43  in the conveyance direction. The first scanning unit  51  is mounted in the upper cover  11 . The second scanning unit  52  is mounted in the chute  14 . For example, the first scanning unit  51  and the second scanning unit  52  face each other vertically with the conveyance path P defined therebetween. A contact image sensor (CIS), a charge coupled device (CCD), or the like may be used as the first scanning unit  51  and the second scanning unit  52 . 
     2. Operation of Image Scanner  1   
     Next, the operation of the image scanner  1  will be described. 
     (1) In the case where only the first tray  21  is used, the first tray  21  is rotated from the position shown in  FIG. 4 , in which the first tray  21  is in the first closed position and the second tray  22  is in the closed position, to the first open position. As illustrated in  FIG. 8 , when the first tray  21  is in the second open position, the end portion  21 I of the first tray  21  is in contact with the engagement protrusion  10 B of the housing  10 . When the first tray  21  is rotated from the second open position to the first open position, the end portion  21 I is pressed by the engagement protrusion  10 B of the housing  10  in the radial direction of the first rotation axis  21 A. The end portion  21 I, which has been pressed, enters the engagement recess  10 C. The end portion  21 I, upon entering the engagement recess  10 C, becomes engaged with the engagement recess  10 C. When the first tray  21  is moved to the first open position, the lower end surface  21 J of the first tray  21  contacts the contact surface  10 D of the housing  10 . When the end portion  21 I is engaged with the engagement recess  10 C and the lower end surface  21 J is in contact with the contact surface  10 D, rotation of the first tray  21  beyond the first open position is restricted. The first tray  21  in the first open position is engaged with the housing  10 . 
     When the first tray  21  is in the first open position, the first tray surface  21 D of the first tray  21  forms an angle of, for example, 180 degrees with the lower guide surface  14 D of the chute  14 . 
     When a high-rigidity sheet is placed on the first tray  21  and fed by the feed roller  41 , the sheet S is conveyed while maintaining a state in which the sheet S extends in the conveyance direction, so that variation in conveyance speed is suppressed and a decrease in the feed performance is suppressed. 
     Examples of a high-rigidity sheet include a business card, a cash card, a membership card, and a driver&#39;s license card. The length of a short side of such a card is, for example, 53.98 mm according to an international standard ID-1 of International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC). The length of a long side of such a card is, for example, 85.60 mm according to the international standard ID-1 of International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC). 
     (2) In the case where the first tray  21  and the second tray  22  are used, the second tray  22  is rotated from the position shown in  FIG. 4 , in which the first tray  21  is in the first closed position and the second tray  22  is in the closed position, to the open position. As illustrated in  FIG. 6 , when the second tray  22  is rotated from the closed position to the open position, the first tray  21 , which is in contact with the second tray  22 , rotates from the first closed position to the second open position in accordance with the rotation of the second tray  22 . When the first tray  21  rotates to the second open position, the end portion  21 I of the first tray  21  contacts the engagement protrusion  10 B of the housing  10 . Thus, the first tray  21  is moved to the second open position, and the second tray  22  is moved to the open position. As a result, the first tray surface  21 D of the first tray  21  is located between and continuous with the lower guide surface  14 D of the chute  14  and the second tray surface  22 B of the second tray  22 . The first tray surface  21 D forms the second angle  82  with the lower guide surface  14 D. 
     When low-rigidity sheets are stacked on the first tray  21  and the second tray  22  and fed by the feed roller  41 , a force is applied to the stack of the sheets S on the first tray  21  and the second tray  22  in the conveyance direction due to the weight of the sheets S. As a result, a load applied to sheets S in a lower part of the stack is decreased. Therefore, friction between sheets S that are in contact with each other is reduced, and a lower sheet of the sheets S can be easily separated from an upper sheet of the sheets S. Examples of a low-rigidity sheet include a sheet of paper, a transparency sheet, or the like. 
     (3) Image Scanning Operation 
     When a sheet S is loaded and an instruction to scan an image of the sheet S is input, a controller controls the feed roller  41  to convey the sheet S on the lower guide surface  14 D in the conveyance direction. The controller includes a CPU, a ROM, a RAM, which are mounted on a circuit board (not shown). At this time, if a plurality of overlapping sheets S are about to be fed, friction is generated between the separation pad  47  and the sheets S, so that the sheets S are separated one by one. 
     The LF roller  42  conveys the sheet S, which has been separated, to the image scanning unit  50 . In the image scanning unit  50 , the first scanning unit  51  and the second scanning unit  52  scan images on both sides of the sheet S. Signals output from the first scanning unit  51  and the second scanning unit  52  are sent to the controller and converted to image data. Then, the ejecting roller  43  ejects the sheet S, whose images have been scanned, to the output section  30 . 
     3. Advantages of Embodiment 
     (1) With the image scanner  1  according to aspects described herein, a card, which is relatively rigid and small, may be placed on the first tray surface  21 D, which is smaller than the second tray  22 , while the second tray  22  is in the closed position. As a result, the second tray  22 , which is longer than the first tray  21 , is not in the open position, so that the size of the space required by the image scanner  1  can be reduced/minimized. 
     (2) In many instances, an image scanner may include a feed tray having an inclination angle with respect to the horizontal direction. In this case, a force is applied to a stack of sheets in the conveyance direction due to the weight of the sheets, and a load applied to a lower part of the stack is decreased. As a result, friction between sheets that are in contact with each other is reduced and a lower sheet can be easily separated from an upper sheet. 
     A conveyance path may extend in the horizontal direction. In this case, a sheet jam due to a sheet that has been output by a sheet output unit is not likely to occur, and the sheet output unit can efficiently output sheets. 
     In the case where the feed tray has an inclination angle with respect to the horizontal direction and the conveyance path extends in the horizontal direction, an extension surface of the tray surface of the feed tray intersects an extension surface of a chute surface of a chute. 
     However, in the case where the extension surfaces of the chute surface and the tray surface intersect each other, and when a sheet having rigidity, such as a card, is conveyed, the sheet is not easily deformed so as to follow the chute surface and the tray surface. Therefore, when the sheet is nipped between the feed roller and a LF roller pair, the sheet applies a large repulsive force to the LF roller pair. The LF roller pair is disposed downstream from the feed roller. The LF roller pair may include a drive roller, which is driven by a motor or the like, and a driven roller, which is rotated by the drive roller and biased against the drive roller. Due to the repulsive force, the sheet, which has rigidity, might not be appropriately nipped. As a result, conveyance performance may deteriorate or decrease. For example variation in the conveyance speed may increase. 
     Moreover, in some instances, the precision of separation decreases and the conveyance performance may decrease due to an increase in the repulsive force applied to the feed roller. 
     In contrast, with the image scanner  1  according to aspects described herein, in the case where only the first tray  21  is used, and when the first tray  21  located in the first open position, the first tray surface  21 D of the first tray  21  forms an angle of nearly 180 degrees with the lower guide surface  14 D of the chute  14 . In this state, when a high-rigidity sheet is placed on the first tray  21  and fed by the feed roller  41 , the sheet S is conveyed while maintaining a position in which the sheet S extends in the conveyance direction, so that variation in conveyance speed and decrease in the conveyance performance are suppressed. 
     In the case where both of the first tray  21  and the second tray  22  are used, the second tray  22  is disposed in the open position and the first tray  21  is disposed in the second open position. In this state, the first tray surface  21 D of the first tray  21  is located between and continuous with the lower guide surface  14 D of the chute  14  and the second tray surface  22 B of the second tray  22 . The first tray surface  21 D forms a second angle θ 2  with the lower guide surface  14 D. In this state, when low-rigidity sheets S are stacked on the first tray  21  and the second tray  22 , a force is applied to the stack of sheets S in the conveyance direction due to the weight of the sheets S and a load applied to the sheets S in a lower part of the stack is decreased, so that friction between sheets S that are in contact with each other is decreased and a lower one of the sheets S can be easily separated from an upper one of the sheets S. Accordingly, it is possible for the image scanner  1  to convey both high-rigidity sheets and low-rigidity sheets. 
     (3) With the image scanner  1  according to the aspects described herein, the first tray  21  is biased from the first open position toward the first closed position due to a biasing force of the torsion spring  21 B, which is fitted onto the first rotation shaft. Thus, by only rotating the second tray  22  from the closed position to the open position, the first tray  21  can be rotated from the first closed position to the second open position. Accordingly, it is not necessary to rotate the first tray  21  and the second tray  22  independently, and convenience for a user can be improved. 
     (4) With the image scanner  1  according to the aspects described herein, when the first tray  21  is in the first open position, the end portion  21 I of the extension portion  21 H of the first tray  21  is engaged with the engagement recess  10 C of the housing  10 . Thus, the first tray  21 , which is biased from the first open position toward the first closed position, can be maintained in the first open position. 
     (5) With the image scanner  1  according to the aspects described herein, the first tray  21  is attached to the back end of the housing  10  so as to be rotatable around the first rotation axis  21 A, which extends in the left-right direction. The second tray  22  is attached to an upper part of the back end of the housing  10  so as to be rotatable around the second rotation axis  22 A, which extends in the left-right direction. Thus, the first tray  21  and the second tray  22  can be rotated with a simple structure. 
     (6) With the image scanner  1  according to the aspects described herein, the length L 1  of the first tray surface  21 D in the conveyance direction is smaller than the length L 2  of the second tray surface  22 B in the conveyance direction. Thus, the size of the image scanner  1  can be reduced. 
     (7) With the image scanner  1  according to aspects described herein, the side guides  21 E and  21 F can be slid along the first tray surface  21 D of the first tray  21  in the left-right direction. The side guides  21 E and  21 F are disposed on the first tray surface  21 D with a space therebetween in the left-right direction. Thus, it is possible to align sheets S in both of the following cases: a case where the first tray  21  is displaced to the first open position and the sheets S are placed only on the first tray  21 ; and a case where the first tray  21  is displaced to the second open position, the second tray  22  is displaced to the open position, and the sheets are placed on the first tray  21  and the second tray  22 . 
     (8) With the image scanner  1  according to the aspects described herein, the sum of the length L 1  and the length L 3  is greater than or equal to the length L 4 . The length L 1  is a length of the first tray surface  21 D in the conveyance direction. The length L 3  is a length from an end of the first tray surface  21 D near the feed roller  41  to the feed roller  41  in the conveyance direction. The length L 4  is a length from the feed roller  41  to the LF roller  42  in the conveyance direction. Thus, in a case where a high-rigidity sheet placed on the first tray surface  21 D is conveyed, the sheet can be easily conveyed by at least one of the feed roller  41  and the LF roller  42 . As a result, the probability that the sheet S is not conveyed by any of the feed roller  41  and the LF roller  42  is reduced, so that a high-rigidity sheet placed on the first tray surface  21 D can be more reliably conveyed. 
     (9) With the image scanner  1  according to the aspects described herein, when the second tray  22  is in the open position, a direction perpendicular to the second tray surface  22 B has a vertically upward component. Thus, sheets S that are stacked on the first tray  21  in the second open position and the second tray  22  in the open position can be more easily pressed against the first tray  21  and the second tray  22  due to the weight of the sheets S. As a result, the sheets S can be more stably supported on the first tray  21  and the second tray  22 , so the sheets S can be conveyed more reliably. 
     (10) With the image scanner  1  according to aspects described herein, the image scanning unit  50  is disposed downstream from the LF roller  42  in the conveyance direction. The image scanning unit  50  is an example of a sheet processing unit that processes a sheet S that is fed by the LF roller  42 . Thus, processing of a sheet fed by the LF roller  42 , such as scanning an image of the sheet, can be performed with higher precision. 
     4. Other Embodiments 
     The present disclosure is not limited to the embodiment described above and can be implemented in various ways as follows. 
     (1) Aspects described herein can be applied to an apparatus other than an image scanner, as long as the apparatus includes a sheet feeder function. For example, aspects described herein can be applied to an image forming apparatus, such as a laser printer or an inkjet printer. 
     (2) The first tray  21  may not rotate around the first rotation axis  21 A extending in the left-right direction and as in the embodiment described above. For example, the first tray  21  may be slid in the front-back direction while changing its inclination angle. In the sliding mechanism, when the second tray  21 , slid from the first closed position, is in the second open position, the inclination angle is the aforementioned first angle θ 2 . When the first tray  21 , slid from the second open position, is in the first open position, the inclination angle is the aforementioned first angle θ 1 . Likewise, for example, the second tray  22  may be slid in the front-back direction while changing its inclination angle. 
     (3) The first tray  21  may be deformable between the first open position and the second open position. 
     (4) The first tray  21  might not be biased by the torsion spring  21 B as in the embodiment described above. For example, the first tray  21  may be biased by a plate spring. 
     (5) The first tray  21  might not become engaged with the housing  10  as in the embodiment described above. 
     (6) The conveyance guide  14 A of the chute  14  might not have a flat plate-like shape as in the embodiment described above. 
     (7) The side guides  21 E and  21 F may not be attached to the first tray surface  21 D. For example, as illustrated in in  FIG. 13 , side guides  14 E and  14 F may be attached to the lower guide surface  14 D of the chute  14 . In  FIG. 13 , the second tray  22  and the second tray stoppers  13 LA and  13 RA are not illustrated. The side guides  14 E and  14 F are disposed with a space therebetween in the left-right direction. The side guides  14 E and  14 F can be slid along the lower guide surface  14 D in the left-right direction. The side guides  14 E and  14 F are configured to be simultaneously slid in opposite directions. Alternatively, a pair of side guides may be attached to each of the first tray surface  21 D and the lower guide surface  14 D.