Abstract:
A sheet feeder configured to hold a separation pad may include a pivotable housing having a connection element for attaching the separation pad. In one example, the connection element may correspond to a protrusion, with the separation pad including one or more corresponding recesses or holes. A fixing member configured to secure the separation pad may be slidably connected in the housing to be slidable, while connected to the housing, between a first position and a second position.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2013-071948 filed on Mar. 29, 2013, the disclosure of which is herein incorporated by reference in its entirety. 
     FIELD 
     The present disclosure relates to a sheet feeding apparatus that feeds a sheet, and an image reading apparatus that reads an image on the sheet fed by the sheet feeding apparatus. 
     BACKGROUND 
     In a sheet feeding apparatus that feeds a sheet, the sheet is fed through the gap between a roller and a separation pad. The roller rotates and feeds the sheet. The separation pad is disposed in a position facing the roller to provide a feed resistance to the sheet. Even when a plurality of sheets are held in a stack, the sheets can be separated and fed one at a time by feeding the sheets through the gap between the roller and the separation pad. In some examples, a combined separation pad may include a separation pad attached to a holder made of hard resin or the like. The combined separation pad is detachably attached to a housing of the sheet feeding apparatus. 
     BRIEF SUMMARY 
     However, when a separation pad is attached to a housing of a sheet feeding apparatus, a component such as a holder may be required, as discussed in the above example of a combined separation pad. The increase in the number of components may increase production costs of the apparatus and a size of the apparatus. 
     Aspects described herein relate to a sheet feeding apparatus in which a separation pad can be detachably attached directly to a housing, and an image reading apparatus (e.g., without requiring a holder). 
     One or more other aspects relate to a sheet feeder comprising a pivotable housing having a connection element configured to receive attachment of a separation pad. In one example, the housing is pivotable between an abutting position and a separation position about an axis extending in a first direction. The separation pad may, in some examples, include another connection element configured to attach to the connection element of the pivotable housing. According to some arrangements, the separation pad contacts the first roller when the separation pad is attached to the pivotable housing and the pivotable housing is in the abutting position and is separated from the first roller when the separation pad is attached to the pivotable housing and the pivotable housing is in the separation position. A fixing member may be configured to contact the separation pad and to be slidable, while connected to the pivotable housing, between a first position and a second position. For example, the fixing member may slide along a first surface of the separation pad. The sheet feeder may be used in various systems include an image reading apparatus and the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an example image reading apparatus with trays in an open position. 
         FIG. 2  is a perspective view showing the example image reading apparatus of  FIG. 1  with the trays in a closed position. 
         FIG. 3  is a sectional view taken along line A-A of  FIG. 1 . 
         FIG. 4  is a sectional view showing an example configuration of the vicinity of the separation roller of the image reading apparatus. 
         FIG. 5A  is a perspective view showing the configuration of an example separation pad assembly according to an illustrative embodiment. 
         FIG. 5B  is a plan view showing the configuration of the separation pad assembly according to an illustrative embodiment. 
         FIG. 5C  is a perspective view showing the configuration of an example separation pad assembly according another illustrative embodiment. 
         FIG. 5D  is a plan view showing the configuration of the separation pad assembly according to the other illustrative embodiment. 
         FIG. 6A  is a perspective view showing the configuration of an example fixing member including a slider and a leaf spring attached to the slider according to illustrative aspects described herein. 
         FIG. 6B  is a perspective view showing an example configuration of the slider. 
         FIG. 6C  is a perspective view showing an example configuration of the leaf spring. 
         FIG. 7  is a perspective view showing the image reading apparatus with a pivotable housing open. 
         FIG. 8  is a sectional view taken along line B-B of  FIG. 7 . 
         FIG. 9A  is a sectional view showing a state in which the fixing member is located in a fixing position. 
         FIG. 9B  is a sectional view showing a state in which the fixing member is located in a detachable position. 
         FIG. 10A  is a perspective view showing a state in which the fixing member is located in the fixing position. 
         FIG. 10B  is a perspective view showing a state in which the fixing member is located in the detachable position. 
         FIG. 10C  is a perspective view showing a state in which the fixing member is located in the detachable position and the separation pad is removed. 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present disclosure will be described by an example. In this embodiment, an image reading apparatus  1  is configured to read an image on a document and to generate data according to the read image. The image reading apparatus  1  is capable of storing generated data in a detachable storage medium such as a memory and/or sending generated data to an external storage device such as a HDD (hard disk drive) of a personal computer through wire or wireless communication. In the following description, in order to make the relative positional relationship between parts of the image reading apparatus  1  easy to understand, the directions “up”, “down”, “left”, “right”, “front”, and “rear” shown in the figures will be used. To facilitate understanding of the orientation and relationship of the various elements disclosed herein, the front, rear, left, right, top, and bottom of the image reading apparatus  1  may be determined with reference to axes of the three-dimensional Cartesian coordinate system included in each of the relevant drawings. 
     As shown in  FIG. 1 , the image reading apparatus  1  has a first tray  3 , a second tray  5 , a third tray  7 , and a pair of extension trays  9 . The first tray  3 , the second tray  5 , the third tray  7 , and the pair of extension trays  9  hold sheets such as documents. The first tray  3 , the second tray  5 , the third tray  7 , and the pair of extension trays  9  are configured to open and close around a housing  10  that forms the main body of the image reading apparatus  1 . 
     The first tray  3  is provided in the rear part, e.g., the upstream part in the sheet feed direction, of the housing  10 . The first tray  3  is configured to rotate about an axis extending in the left-right direction with a hinge  3 A (see  FIG. 7 ). The second tray  5  is connected to one end of the first tray  3  opposite to the housing  10  and rotatable about an axis extending in the left-right direction with a hinge  5 A. The third tray  7  is connected to one end of the second tray  5  opposite to the first tray  3  and rotatable about an axis extending in the left-right direction with a hinge  7 A. 
     When the first tray  3 , the second tray  5 , and the third tray  7  are opened away from the housing  10 , surfaces of the first tray  3 , the second tray  5 , and the third tray  7  form a surface (e.g., a continuous surface) for holding sheets such as documents as shown in  FIG. 1 . The pair of extension trays  9  is provided on one end of the third tray  7  opposite to the second tray  5 . The extension trays  9  are rotatable about a pivot provided in the center of third tray  7  in the left-right direction. By spreading the extension trays  9 , the third tray  7  can be extended. The extension trays  9  are retracted into the third tray  7  through openings  7 B formed in the one end of the third tray  7  opposite to the second tray  5 . 
     When the extension trays  9  are refracted into the third tray  7 , and the first tray  3 , the second tray  5 , and the third tray  7  are closed toward the housing  10 , the first tray  3 , the second tray  5 , and the third tray  7  are disposed so as to conform to the outer surface of the housing  10  as shown in  FIG. 2 . 
     As shown in  FIG. 1  and  FIG. 3 , the housing  10  has a first housing  12 , a second housing  11 , and a pair of side plates  13 . The second housing  11  is disposed above the first housing  12  in the orientation shown in  FIGS. 1 and 3 . The pair of side plates  13  is provided on the left and right sides of the second housing  11  and the first housing  12 . As shown in  FIG. 3 , a chute  12 A is formed on the upper surface of the first housing  12 . The chute  12 A forms a sheet feed surface together with the opened first tray  3 . A separation roller  15 , an example of a first roller, is exposed at the rear end of the chute  12 A from below. A contact surface  21 A of a separation pad  21 , an example of a first surface, is in contact with the upper surface of the separation roller  15  (see  FIG. 4 ). When sheets (not shown), such as documents, are held on the opened first tray  3 , the second tray  5 , and the third tray  7 , and when the separation roller  15  is driven, the sheets are fed forward through the gap between the separation roller  15  and the separation pad  21  one at a time in an order starting with the sheet in contact with the separation roller  15 . The separation pad  21  forms a separation pad assembly  20  together with a film  22 . The position in the left-right direction of the fed sheet is defined by a pair of guides  3 B provided on the first tray  3 . The pair of guides  3 B is symmetrically interlocked with respect to the center in the left-right direction by a rack-and-pinion interlocking mechanism  3 C. 
     As shown in  FIG. 3 , a pair of upper and lower feed rollers  16  is provided in front of the separation roller  15  in the housing  10  (e.g., downstream of the separation roller  15  in the sheet feeding direction). A pair of upper and lower paper ejection rollers  17  is provided at the front ends of the second housing  11  and the first housing  12 . The sheet fed forward by the separation roller  15  is then fed through the feed rollers  16  to the paper ejection rollers  17 . The paper ejection rollers  17  eject the fed sheet to the outside of the housing  10 . A pair of contact image sensor (CIS) units  18  and  19 , an example of a reader, configured to read images on the sheet from both above and below are provided over and under a sheet feed path leading from the feed rollers  16  to the paper ejection rollers  17 . The upper CIS unit  18  is provided in the second housing  11 , and the lower CIS unit  19  is provided in the first housing  12 . 
     As shown in  FIG. 1 , a display unit  11 B configured to display information is provided in a center of an upper surface  11 A of the second housing  11 . The display unit  11 B includes a touch panel configured to act as an input device. The upper surface  11 A and the display unit  11 B do not face directly vertically upward but are slightly inclined forward. Therefore, the visibility and operability from the front of the image reading apparatus  1  can be improved. When the first tray  3 , the second tray  5 , and the third tray  7  are closed as shown in  FIG. 2 , an opening  5 B formed in a center of the second tray  5  is located over the display unit  11 B. Therefore, even when the first tray  3 , the second tray  5 , and the third tray  7  are closed, the display unit  11 B is exposed through the opening  5 B to allow for viewing and operation. 
     As shown in  FIG. 4 , the second housing  11  has a supporting portion  30  in a part thereof behind a bearing portion  11 F that bears the upper feed roller  16 . The supporting portion  30  supports the separation pad assembly  20  and a pair of sheet holddown members  27  (see  FIGS. 10A to 10C ) disposed on the left and right sides of the separation pad assembly  20 . The configuration of the supporting portion  30  will be described in further detail below. 
     As shown in  FIG. 4 , the separation pad  21  is supported by the supporting portion  30  on the upstream side in the sheet feed direction, e.g., the upper side of the separation pad  21 . At the distal end of the separation pad  21  (e.g., in the sheet feed direction), the contact surface  21 A is in contact with the separation roller  15 . The aforementioned distal end of the separation pad  21  is located on the downstream side in the sheet feed direction, e.g., the lower side. A planar supporting surface  31  is formed on the lower surface of a rear part of the supporting portion  30 . A bulge portion  32 , an example of a second engaged portion, which bulges both upward and downward from the second housing  11 , is formed at the rear end of the supporting surface  31 . Two protrusions  31 A and  31 B are formed on the supporting surface  31  (see  FIGS. 10A to 10C ). Holes  20 A and  20 B formed in the separation pad assembly  20  are configured to engage with the protrusions  31 A and  31 B, respectively, and the separation pad assembly  20  is thereby attached to the supporting surface  31  (see  FIGS. 5A to 5D ). The holes  20 A and  20 B extend through the separation pad  21 . 
     As shown in  FIG. 5A , the separation pad  21  is formed of an elastic material in a sheet-like shape that is rectangular in plan view. For example, a silicone rubber containing cork may be used as an elastic material. The contact surface  21 A of the separation pad  21  provides a feed resistance to the sheet in a position facing the separation roller  15 . A film  22  made of resin, e.g., PET (polyethylene terephthalate) or the like is attached to a back surface  21 B, an example of a second surface, opposite to the contact surface  21 A. The film  22  is attached to the back surface  21 B at the distal end portion  22 A on the downstream side in the sheet feed direction and at the proximal end portion  22 B on the upstream side. The film  22  is disposed in a bent state, and therefore the middle portion  22 C between the distal end portion  22 A and the proximal end portion  22 B is out of contact with (e.g., does not contact) the back surface  21 B. The proximal end portion  22 B of the film  22  is attached to the back surface  21 B of the separation pad  21  with a proximal end portion  23 B of an elastomer sheet  23  therebetween. The elastomer sheet  23  is formed, for example, of acrylic elastomer. The elastomer sheet  23  extends, in the center in the left-right direction of the back surface  21 B, along the back surface  21 B. A distal end portion  23 A of the elastomer sheet  23  is disposed between the middle portion  22 C and the back surface  21 B. An opening  22 D is formed in a part of the middle portion  22 C of the film  22  facing the distal end portion  23 A of the elastomer sheet  23 . 
     The holes  20 A and  20 B are formed in a part of the back surface  21 B of the separation pad  21  to which the proximal end portion  22 B of the film  22  is attached. The holes  20 A and  20 B are formed on both sides of the proximal end portion  23 B of the elastomer sheet  23  as shown in  FIG. 5B . The hole  20 B is greater in diameter than the hole  20 A, and accordingly, the protrusion  31 B engaging with the hole  20 B is greater in diameter than the protrusion  31 A engaging with the hole  20 A (see  FIG. 10C ). Therefore, the hole  20 A is prevented from being accidentally engaged with the protrusion  31 B, and the separation pad assembly  20  is thereby prevented from being attached to the supporting surface  31  in the incorrect orientation (e.g., with the wrong side up). 
     Returning to  FIG. 4 , a biasing member  33 , a spring  34 , and a spring receiving portion  35  are provided in a part of the supporting portion  30  facing the separation roller  15 . One end of the spring  34  is attached to the biasing member  33 . The other end of the spring  34  is borne by the spring receiving portion  35 . The biasing member  33  is formed in an elongate shape extending throughout the width in the left-right direction of the separation pad assembly  20  (see  FIG. 10C ). The biasing member  33  receives basing force from the spring  34  and presses the separation pad assembly  20  toward the rotation axis of the separation roller  15 . 
     The pair of sheet holddown members  27  is disposed on both the left and right sides of the separation pad  21  (e.g., one of members  27  on each side of separation pad  21 ). The pair of sheet holddown members  27  is in contact with the separation roller  15  and thereby biases the sheet against the separation roller  15 . The pair of sheet holddown members  27  is connected to each other by a wire  28  for grounding. For example, the static electricity generated by friction is removed through the wire  28 . The wire  28  is fixed to the supporting portion  30  with a screw  29  from above. A screwing portion  37  of the supporting portion  30 , into which the screw  29  is screwed, bulges downward from the supporting portion  30 , and is in contact with the film  22  when the separation pad assembly  20  is attached. 
     A protruding portion  38  is provided above the bulge portion  32 . The protruding portion  38  is connected to the rear end face of the second housing  11 , and is in contact with the upper surface  11 A of the second housing  11  from below. A gap is formed between the protruding portion  38  and the bulge portion  32 . A leaf spring  50  (e.g., an upper tongue portion  50 B described in further detail below, see  FIG. 6C ) supporting a slider  40  can be inserted into the gap. 
     As shown in  FIG. 6A , in one example, a fixing member  60  has a slider  40  made of resin, and a leaf spring  50  made of metal and attached to the slider  40 . As shown in  FIG. 6B , the slider  40  has a main body portion  41 , a rear portion  42 , and a pair of side plates  43 . The main body portion  41  is disposed on the contact surface  21 A side of the separation pad  21 . A plurality of ribs  41 A are formed on the upper surface of the main body portion  41  along the sheet feed direction. The rear portion  42  is disposed behind the bulge portion  32 . The pair of side plates  43  supports the main body portion  41  and the rear portion  42  from both the left and right sides. The pair of side plates  43  supports the main body portion  41  and the rear portion  42  such that they separate from each other. 
     As shown in  FIG. 6C , the leaf spring  50  made of metal has a lower tongue portion  50 A, an upper tongue portion  50 B, and a connecting portion  50 C. The lower tongue portion  50 A is passed through a space surrounded by the main body portion  41 , the rear portion  42 , and the pair of side plates  43 , and is placed on the upper surface of the main body portion  41 . The upper tongue portion  50 B is placed on the side of the supporting portion  30  opposite to the supporting surface  31 . The lower tongue portion  50 A and the upper tongue portion  50 B are connected to each other at their rear ends by the connecting portion  50 C. The connecting portion  50 C is in contact with the rear end face of the rear portion  42 . In the illustrated example, the leaf spring  50  is formed generally in a substantially C-shape (e.g., when viewed from the side). The lower tongue portion  50 A is in contact with the upper surfaces of the plurality of ribs  41 A. The distal end of the lower tongue portion  50 A is bent downward (e.g., toward the main body portion  41 ). The proximal end of the bent part is a contact portion  51  that is in contact with the separation pad  21  in front of the ribs  41 A. 
     An engaging portion  52  is formed at the distal end (e.g., relative to connecting portion  50 C) of the upper tongue portion  50 B. The engaging portion  52  is bent in a V-shape toward the lower tongue portion  50 A. As shown in  FIG. 4 , a recess  39 , an example of a first engaged portion, is formed in the side of the supporting portion  30  opposite to the supporting surface  31 . The recess  39  engages with the engaging portion  52  when the leaf spring  50  is inserted in a forward direction (e.g., toward a front portion of the apparatus). A restricting portion  53  is formed in the upper tongue portion  50 B. The restricting portion  53  is cut and raised in an upward direction, e.g., away from the lower tongue portion  50 A. The restricting portion  53  comes into contact with the protruding portion  38  when the leaf spring  50  is extracted in a rearward direction from the supporting portion  30 . 
     As shown in  FIGS. 6A to 6C , when the leaf spring  50  is attached to the slider  40  and the connecting portion  50 C comes into contact with the rear end face of the rear portion  42 , a hook  44  formed on the main body portion  41  engages with a square hole  54  formed in the leaf spring  50 . The leaf spring  50  is thereby fixed to the slider  40 . 
     As shown in  FIG. 7  and  FIG. 8 , the second housing  11  is rotatably connected to the first housing  12 . The second housing  11  rotates about a rotating axis J. The rotating axis J is located on the downstream side in the sheet feed direction of the separation pad  21 , and extends in the left-right direction which is an example of a first direction. Therefore, the second housing  11  can be displaced between an abutting position where the separation pad  21  is in contact with the separation roller  15  (see  FIG. 1  to  FIG. 4 ) and a separation position where the separation pad  21  is separated from the separation roller  15  (see  FIG. 7  and  FIG. 8 ). 
     When the second housing  11  is in the separation position, the separation pad assembly  20  and the fixing member  60  are exposed above the image reading apparatus  1  as shown in  FIG. 8 , and therefore the separation pad assembly  20  can be easily replaced as follows. In the separation position, the contact surface  21 A of the separation pad  21  is visible from above, and therefore the attrition condition of the contact surface  21 A can be easily checked. 
     As shown in  FIG. 9A , when the fixing member  60  is pushed to a fixing position, an example of a first position, where the rear portion  42  of the slider  40  is in contact with the bulge portion  32 , the engaging portion  52  engages with the recess  39 . The fixing member  60  is held stably in the fixing position. For example, the fixing member  60  covers a part of the contact surface  21 A of the separation pad  21 . At this time, the contact portion  51  is in contact with the contact surface  21 A of the separation pad  21  on the downstream side in the sheet feed direction of the protrusions  31 A and  31 B. The contact portion  51  receives the restoring force of the leaf spring  50  and is biased against the contact surface  21 A. Therefore, when the fixing member  60  is located in the fixing position, the protrusions  31 A and  31 B cannot be disengaged from the holes  20 A and  20 B, and the separation pad assembly  20  is well fixed to the supporting surface  31 .  FIGS. 9A and 9B  are enlarged sectional views showing the movement of the vicinity of the separation pad assembly  20  in  FIG. 8 , and the position of the second housing  11  corresponds to that shown in  FIG. 7  and  FIG. 8 . 
     When the fixing member  60  is moved upward, e.g., to the upstream side in the sheet feed direction, from the fixing position shown in  FIG. 9A , the contact portion  51  moves along the contact surface  21 A of the separation pad  21  while being in contact with the contact surface  21 A, and comes out of contact with the separation pad  21  as shown in  FIG. 9B . When the fixing member  60  is located in this detachable position, which is an example of a second position, the protrusions  31 A and  31 B can be disengaged from the holes  20 A and  20 B, and the separation pad assembly  20  can be detached from the supporting surface  31 . When the fixing member  60  is located in the detachable position, the engaging portion  52  (an example of a second engaging portion) engages with the bulge portion  32 , and the fixing member  60  is thereby held by the supporting portion  30 . In addition, the restricting portion  53  comes into contact with the protruding portion  38 , and the fixing member  60  is thereby restricted from moving upward, e.g., upstream in the sheet feed direction. Therefore, when the separation pad is replaced, the fixing member  60  can be held in the detachable position so as not to come off (e.g., detach from) the supporting portion  30 . 
     The protruding portion  38  has, in its center, a hollow space extending in the left-right direction. The protruding portion  38  does not include a portion facing the leaf spring  50  on the downstream side in the sheet feed direction. The protruding portion  38  has a substantially U-shaped cross-section in side view. In the detachable position, the restricting portion  53  is in contact with a wall portion  38 A of the protruding portion  38 . The wall portion  38 A, which is a longer wall of the protruding portion  38  than, e.g., an exterior wall of protruding portion  38 , is located upstream in the sheet feed direction. When the fixing member  60  is moved from the detachable position to the fixing position, the contact portion  51  also moves along the contact surface  21 A of the separation pad  21  while being in contact with the contact surface  21 A. 
     In this embodiment, the replacement of the separation pad assembly  20  is made possible by moving the fixing member  60  from the fixing position shown in  FIG. 10A  to the detachable position shown in  FIG. 10B . In the fixing position, the separation pad assembly  20  is fixed to the supporting surface  31  (see  FIG. 10C ). In the detachable position, the holes  20 A and  20 B of the separation pad assembly  20  can be disengaged from the protrusions  31 A and  31 B, and the fixing member  60  is not in contact with the separation pad assembly  20 . From a state where the fixing member  60  is located in the detachable position, the separation pad assembly  20  can be detached as shown in  FIG. 10C . When holes  20 A and  20 B of a new separation pad assembly  20  are engaged with the protrusions  31 A and  31 B as shown in  FIG. 10B  and the fixing member  60  is located in the fixing position as shown in  FIG. 10A , the replacement of the separation pad assembly  20  is completed. 
     As described above, in this embodiment, the separation pad assembly  20  can be attached and detached directly to and from the second housing  11  with no need to combine the separation pad assembly  20  to a holder prior to attachment. Therefore, for example, when the contact surface  21 A of the separation pad  21  is worn|[AM1], replacing the separation pad assembly  20  makes it possible to better feed sheets one at a time and to read images thereon with the CIS units  18  and  19 . The separation pad assembly  20  is not combined with a holder or the like, and therefore the number of components can be reduced, the production cost can be reduced, and the apparatus can be well downsized. 
     The fixing position is on the downstream side in the sheet feed direction of the detachable position. Therefore, if the fixing member  60  comes into contact with the fed sheet at the time of image reading, the fixing member  60  is prevented from being dragged by the sheet and from thereby moving from the fixing position to the detachable position. In addition, the engaging portion  52  engages with the recess  39  in the fixing position, and therefore the fixing member  60  is better held in the fixing position. Therefore, in the fixing position, the separation pad assembly  20  can be fixed to the supporting surface  31  more stably. 
     In the fixing position, the contact portion  51  is in contact with the separation pad  21  on the downstream side, in the sheet feed direction, of the protrusions  31 A and  31 B, and is biased against the separation pad  21  by the leaf spring  50 , and therefore the protrusions  31 A and  31 B can be better prevented from being disengaged from the holes. Therefore, the separation pad assembly  20  can be better fixed to the supporting surface  31 . 
     The present disclosure is not limited to the embodiment, and may be embodied in various forms without departing from the scope of the present disclosure. For example, as shown in  FIGS. 5C and 5D , the elastomer sheet  23  may be omitted, and the film  22  may also be omitted. The holes  20 A and  20 B, may be recesses that are not formed through the separation pad  21 . The restricting portion  53  and so forth may be omitted, and the fixing member  60  may be easily detachable from the second housing  11 . Although the contact portion  51  is in contact with the contact surface  21 A that comes into contact with the sheet, the contact portion  51  may be in contact with the back surface  21 B. The sheet feeding apparatus of the present disclosure can be used in various apparatuses such as an image forming apparatus.